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toolmaker76
02-01-2010, 10:30 PM
I guess the old fogey in me is showing, but this CNC thing is getting to me.

I am not going to argue the merits of CNC- they are fantastic machines and can do work in minutes that I can remember taking days to do. However, speaking from the standpoint of one who started this trade before CNC was widely available (and if it was, it was called NC with punched paper tape) there is an attitude about it these days that it is superior to all other types of machining.

Yes, it can do things precise, and repeatable, but what if that is not necessary? What if your tolerance was such that you didn't require that kind of precision? I am thinking set ups with mill stops, that you could drill holes or make quick bores or tap holes. You can run a pile of parts with all the same hole size/ location, then change position, drill, tap, etc. and run them all back through. To me, your accuracy is there, and you save the time of programming. In addition, your CNC cycle time would probably be greater because it (assuming a machining center) has to stop for tool changes and so forth. Not talking willy nilly careless set ups here, just some old time common sense stuff.

Have had a couple of situations recently where the attitude is that it can't be done right without CNC! My point is precise is precise, no matter how it is achieved, but that is getting hard to sell!

Yep, I can run CNC mills and lathes (and even EDM machines). It just amazes me that people (customers) are getting to believe that it is the only way that work can be done right! Just had to bark a bit!

Carld
02-01-2010, 10:54 PM
I know exactly what your saying toolmaker. I started on manual machines and never did get training for CNC. Several shops I worked in had them and I did all the manual machine work. I never have been interested in learning CNC or buying one.

I have to admit that there are things they can do easier than a manual machine but they are not the end all to machining. There is plenty of things the manual machines outshine CNC at. Making a one off complicated part is one thing for sure.

There are still thousands of screw machines pumping out parts as well. Turret lathes still do a good job. Anyone that thinks CNC is the only way to go has a closed mind and may have no exposure to manual machines so they have no concept of what a manual machine and a good machinist can do.

JTToner
02-01-2010, 10:56 PM
Have had a couple of situations recently where the attitude is that it can't be done right without CNC! My point is precise is precise, no matter how it is achieved, but that is getting hard to sell!

That, unfortunately, is so dern true. We won WW2 with manual machines. Today, I doub't it possible to get a gov't contract w/o CNC machines. Yes, they are great, and yes, they will do complex shapes, and yes, I even plan to but a VMC and ta urning center, but still, I have to agree with you. Seems CNC has become a religion. Seems most of the Chicom crap we get here is like +/- 1/8". The last two factories I worked in rarely required tighter than +/- .005". This was usually for interchangeability of replacement parts and/or automated assembly of mass produced consumer goods (door locks). I was just ran an automatic punch press.

Of course, our tool and die men worked to very tight tolerances, and that was strictly on manual machines. I left 25 years ago and already there was a lack of qualified American T&D men as nearly all of our guys were from the UK or Europe.

old blue
02-01-2010, 11:01 PM
At my day job we have 4 cnc mills and 2 cnc lathes, we just got the 2nd
lathe. Not sure what the new lathe will do but with the old Cincinnati
most of the bearing tolerance stuff is still done on the manual lathes.

wierdscience
02-01-2010, 11:03 PM
I've seen that,I've also seen where people automatically assume CNC is cheaper for they're particular part.

Lately I have seen a trend toward people who don't know how to make the part,don't know what to make it out of and don't know what tolerance they need.They also don't believe the machinist/engineer when they give them an answer????? They don't know,so they ask and then argue WTF?:confused:

I was asked for a quote on a bunch of plate burnouts(I don't do them I farm them out normally)I got a quote from the plasma cutter,added my commission in on it and faxed them a quote mentioning the plasma cutter had a 3 day leadtime.
I got a question back from them asking why I wasn't personally doing them(I have a fan base apparently)I told them the gospel truth,CNC plasma was cheaper and faster in this case and it would cost them more if I did them the old way.
The next question I got was "well,can we deal with them direct?":rolleyes:

My answer-"Yes,certainly,but since I am offering you the parts I would have charged $750 for ,in less time,in better quality for $560 I figure they're phone number and my contact is worth $200 at least":D

Lesson for the week,some customers are better off as Mushrooms,kept in the dark and fed s---.:cool:

Carld
02-01-2010, 11:37 PM
WS, I have been reluctant to tell a customer I was farming them out for just the reason you mentioned.

The one time I did tell my customer I told him to call them, gave him the number and name and he said he didn't want to fool with it, he had more important things to do and for me to be the middle man. I was kind of surprised because I really didn't want to be the middle man. I didn't make much on it because I did all the disign, drawings, part gathering and farming out the CNC work.

On the other hand, he is a very good customer and I do all his machine work at the main shop so I couldn't refuse to help him on it. They have several branches around the East.

bborr01
02-02-2010, 12:09 AM
I have two good friends that run pretty successful shops.

They both have cnc's and manual machines. The manual machines are rarely used. Although one of them uses his manual lathe because he has no cnc lathe.

Bottom line is that they use the cnc's so much that they can program for single piece jobs faster than they can do the job manually.

The tools are setup in tool changers so there is little measuring of the part, edge finding etc.

I still think that sometimes the manual machines would be a better choice for some of the jobs they do. They just don't use them.

I am just breaking into cnc's for my home shop. There are some things such as profiling that the cnc's easily do that are almost impossible to do on a manual machine.

I am told that the buggie makers said the same thing about those new things called automobiles. Don't see a lot of buggies out there except in Amish country.

Come to think of it, the Amish seem to do pretty good without cars.

Brian

wierdscience
02-02-2010, 12:24 AM
WS, I have been reluctant to tell a customer I was farming them out for just the reason you mentioned.

The one time I did tell my customer I told him to call them, gave him the number and name and he said he didn't want to fool with it, he had more important things to do and for me to be the middle man. I was kind of surprised because I really didn't want to be the middle man. I didn't make much on it because I did all the disign, drawings, part gathering and farming out the CNC work.

On the other hand, he is a very good customer and I do all his machine work at the main shop so I couldn't refuse to help him on it. They have several branches around the East.

The smart customers I have figure the shops I am doing business with don't do walkin work and they are right.I find it's easier if I tell them what I'm farming out ahead of time rather than having a glitch with delivery and them finding out the hard way.

The example I gave seems to be a growing trend in new customers.They have not a clue about anything,but they think they do.The ones that don't come back I'm better off without and the ones that are humble enough to admit they don't know and come back are keepers.

Evan
02-02-2010, 12:49 AM
The only commercial shop that I am familiar with is the one in town where I buy my supplies. I know the owners and the staff including tha machinists and fabricators. There are about a dozen main machines, mills and lathes of various sizes range from medium to big (40" swing). They are all manual and there isn't likely to be a CNC machine in there any time soon. It won't do they job that they need to do which is most one off repair parts that are needed now and not a month from now when it finally arrives from the manufacturer for the faller/buncher XYZ 3000.

I built my self a CNC mill for a several of reasons. I needed a milling machine. My hands are weak.

But the big reason is that I can and do use it to make things that cannot be made without CNC or would be very difficult to make any other way. I do a lot of fancy engraving and I make oddball parts like a ten inch sector gear with 20 teeth per inch. I use it to sharpen end mill flutes and to cut aspherical mirrors from solid aluminum. I have used it to generate metallic surface holograms, engrave photographs and even to play music. :D

It also does a good job of agitating the etch tank when making circuit boards.

dp
02-02-2010, 12:58 AM
I do a lot of fancy engraving and I make oddball parts like a ten inch sector gear with 20 teeth per inch. I use it to sharpen end mill flutes and to cut aspherical mirrors from solid aluminum. I have used it to generate metallic surface holograms, engrave photographs and even to play music. :D.

And jewelry!

beanbag
02-02-2010, 01:16 AM
Ever since I started using the CNC, I think that they are the greatest thing ever, and only use the manual mill for the most menial and imprecise tasks.

dp
02-02-2010, 02:00 AM
Ever since I started using the CNC, I think that they are the greatest thing ever, and only use the manual mill for the most menial and imprecise tasks.

How has that affected job turn-around time? I've wondered if CNC can keep up with non-trivial but low yield jobs - say less than 10 parts in a one-off batch, vs manual.

macona
02-02-2010, 02:28 AM
With a machine that has decent conversational programming its way faster than a mill. For example the base plate on my vacuum system. Put it in the VMC, had it mill out a hole 5.5" in diameter through 1.25" thick aluminum then drill 8 holes concentric to the hole on a 5" radius and then tap those holes. Took about 1/2 hr. There is no way I could have done this on a manual mill in one setting. Even drawing the part in cam real quick would have only added 20 to 30 minutes to the job. Still faster than doing it manually.

Even for one off parts I have found the CNC mill to be faster. You can operate it like a standard mill with power feeds if you use the handwheel. Lathes are a different story. I prefer to use a manual machine for most ops. Maybe its just because I really havnt used my CNC lathe much.

beanbag
02-02-2010, 02:56 AM
How has that affected job turn-around time? I've wondered if CNC can keep up with non-trivial but low yield jobs - say less than 10 parts in a one-off batch, vs manual.

Unless it's a one-off of a menial and imprecise task, the CNC is generally faster. There are a bunch of other benefits too, like:

If you get the first part right, you WILL NOT screw up on any of the rest. This is very helpful if you've been working continuously for 6 hrs and are starting to get pretty tired.

Your tools last longer because you can do things like climb cut, don't dwell while you are alternating between the x and y axis, have more efficient and expeditious toolpaths, etc

You can be busy doing other things like planning for the next part while the machine is busy churning on the current batch

Even for doing something rote like drilling a series of holes in 1/2" steel, I prefer to do on the CNC because you can just turn on the flood coolant and let it go. It will use a continuous feed rate and won't work harden the material.

The only tool I haven't used on the CNC is the slitting saw, because I can't turn it off fast enough if something goes wrong.

John Stevenson
02-02-2010, 04:20 AM
You have to differentiate here between home shop and work, then split that up into one off's and production, so basically you have four different groups all requiring a different method of doing a job.

Then throw into the equation that two people, doing the same job, with the same machinery won't do it the same way.

That gives you the correct answer :D :D

I'm a big believer in CNC as many know but my main machine often stands idle for a couple of weeks at a time or just ticks over making division plates for Gert to sell.

Guy up the road, one man band, lives on his Hurco and would be lost without it.

.

Mark Hockett
02-02-2010, 04:22 AM
there is an attitude about it these days that it is superior to all other types of machining.

They are superior or they wouldn't be the machine of choice for the majority of machine shops world wide. I have a shop full of CNC and manual machines. There is rarely anything I do that can't be done faster and more accurate on a CNC machine. Who says you need a program for every little move you make. I use the MPG wheel for facing and edge cuts all the time. One of my machines has a tool changer but who says I can't just hand load a tool if needed, I just push a button and its in, which is much faster than unscrewing a draw-bar.

Many old timers that haven't seen or used modern conversational CNC machines have no concept of how fast and easy they are to program. My CNC lathe is way faster than using a manual lathe. You just answer a few questions and hit the start button. It will create complex parts with radii or chamfered edges and roughing and finishing cycles with just a handful of questions answered. I can have a finished part before a manual lathe would make the first step and be within a few tenths. I have a CNC mill that is the same way, answer questions and hit start.

Setting up tools is no different on CNC than a manual machine. On a manual mill don't you still have to put the tools in a holder? no different on a CNC. On a manual mill don't you locate your position and zero you micrometer dial or DRO? it's no different on a CNC. My VMC has features for set up that allow you to find the center of a circle by touching the edge finder to 3 points (no co-ax or DTI needed), find the center of a part by touching two points and it finds a corner by touching two edges. It will do the math and with the push of a button will input the info into the work offset. It also automatically compensates for the radius of the edge finder. I will be making chips before the average guy is done zeroing his dials on a manual mill.

One thing I really like about my CNC lathe is I can do things that to do on a manual lathe require extra expensive tooling. I can cut tapers without a taper attachment, I can cut radii without a radius attachment, I can thread to within .001" of a shoulder on an outside or inside thread at 1500 RPM and I can use the lathe as a CNC shaper to cut key ways or automatically index the spindle and cut splines with a form tool. My lathe also has a feature to remove taper called taper compensation. Guys complain here all the time that they get a taper when cutting between centers or with the part sticking too far out of the chuck. On my lathe you just measure each end of the part, divide the difference by the length and enter that number into the taper comp offset and the lathe will cut straight. How many hours do some guys spend shimming and dialing in their tail stocks? I doesn't matter if my tail stock is off.




What if your tolerance was such that you didn't require that kind of precision? I am thinking set ups with mill stops, that you could drill holes or make quick bores or tap holes. You can run a pile of parts with all the same hole size/ location, then change position, drill, tap, etc. and run them all back through. To me, your accuracy is there, and you save the time of programming. In addition, your CNC cycle time would probably be greater because it (assuming a machining center) has to stop for tool changes and so forth. Not talking willy nilly careless set ups here, just some old time common sense stuff.

I think what you are talking about here is a drill press not a mill. But there is no reason you can't run your CNC this way too. I do lots of second operations on my CNC knee mill where there is no tool change and the spindle never turns off between parts.

Here is a simple part I make on my CNC knee mill, how long would this take on a manual mill,
http://www.youtube.com/watch?v=NpbN1UDwtQM

That mill cost me less than the average Bridgeport, I payed $1250 and it was in perfect working order. Two of my friends just bought identical mills for not much more than I payed,

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300386415389&ssPageName=STRK:MEWAX:IT

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300386415336&ssPageName=STRK:MEWAX:IT




Have had a couple of situations recently where the attitude is that it can't be done right without CNC! My point is precise is precise, no matter how it is achieved, but that is getting hard to sell!
There is a post on the Chaski board that is a great example of the advantage of CNC. Gary needed a very tiny handle made for an elevation screw on a model cannon. There were many opinions offered on how to make them. Resin molds, radius attachments, free hand turning, hydraulic tracer and form tools. I had 12 of them done accurate to his drawing in less than an hour with programming and machining, each part took 1 minute 37 seconds. He sent me a drawing and I programmed the part on my lap top with my CAM system while eating dinner at the dinner table, it was that easy. Here is the part,
http://i24.photobucket.com/albums/c10/mahockett/t_elevating_screw_and_box_873.jpg

Here is a link to the post,
http://www.chaski.org/homemachinist/viewtopic.php?t=83364&postdays=0&postorder=asc&start=0

and here is a video of the lathe cutting one. It would have been faster but the smallest diameter 1144 stock I had was 5/8 and this was with my old slow tool turret, I now have a high speed turret with 2 second tool changes on that lathe.
http://www.youtube.com/watch?v=5ZcEmkvdp-g

.RC.
02-02-2010, 04:44 AM
All very good and well, but what does a decent CNC machine with good conversational programming cost??

Certainly a lot more then a manual machine... Well that is the situation in this country.. I saw a Haas TL1 second hand sell for $30 000..That was probably the sort of money you will spend on a good industrial CNC machine..

DR
02-02-2010, 05:09 AM
.................................................. .....................

I have to admit that there are things they can do easier than a manual machine but they are not the end all to machining. There is plenty of things the manual machines outshine CNC at. Making a one off complicated part is one thing for sure.

.................................................. .......................



Several posters have expressed the same thing. That a one -off of a complicated part is easier on a manual machine.

Actually, that's totally backward, a complicated one-off is far, far easier on a CNC.

DR
02-02-2010, 05:17 AM
All very good and well, but what does a decent CNC machine with good conversational programming cost??

Certainly a lot more then a manual machine... Well that is the situation in this country.. I saw a Haas TL1 second hand sell for $30 000..That was probably the sort of money you will spend on a good industrial CNC machine..

The good news is "modern" style CNC's have been around long enough that good used "industrial" grade machines are available for well under $10K.

A TL1 for $30K? It would depend what options it had. It's entirely possible that wasn't a bad price although it does seem high. Those Haas machines tend to bring top dollar on the used market.

.RC.
02-02-2010, 05:33 AM
The good news is "modern" style CNC's have been around long enough that good used "industrial" grade machines are available for well under $10K.


Maybe in the US.. Not here...

Don't get me wrong, I love CNC and it's capabilities, but it is expensive... A bit like how in the pre-CNC era industrial manual machines were expensive items and hobbyists simply could not afford them and could only afford little machines like South Bends and Myfords...

I have a near new Chinese round column geared head Mill Drill here that one day I hope to convert to CNC..

EVguru
02-02-2010, 05:40 AM
I work at a scientific research site making custom electronics, instruments, data loggers, etc.

The traditional method of producing one off instruments was on stripboard and I remember all the problems we used to get with signal paths, fault finding and the very maddening hairline cracks. Sometimes we would need to produce quite a number of circuits and we gradually build up the facilities to etch our own printed circuit boards. That of course led to a CNC drilling machine.

Over the last few years, I've made a new control card for the drill with PIC code in C and a PC application in VB6. In conbination with the Protel Altium PCB CAD/CAM software it's now easier and faster to make a one off circuit as a PCB, rather than on stripboard and all the doccumentation is integral to the creation process.

toolmaker76
02-02-2010, 06:32 AM
I have a few on here who may not understand my original post, so I will try another way around it.

You don't have to sell me on CNC- I use CNC mills and lathes on a daily basis. What I get tired of dealing with is the attitude that it is not right if it is not done on CNC, or that it can't be run as part of a production setup without doing it on CNC. There are some things that are not appropriate to set up with a CNC, yet some customers have the belief that it is a matter of fudging if the job wasn't programmed and run on a CNC machine.

You can program a hole to be drilled 1" from an edge. You can make a set up on a drill press or a mill to make the hole 1" from an edge. At the end of the day, aren't they 1'' from the edge either way? If your CNC machines are busy with paying work, and you have other jobs that can be done on CNC, but you are not really losing money to run them in manual, doesn't it make sense to get that work closer to the cash register (the goal when the job is finished)?
That may be presenting the observation a different way so that it is understood.

Have a job in the shop now that will be run on CNC because that is what the customer wants. Because it is an odd size and not flat, it will require a very complicated set up to do this, and this is just to take off a small high spot. It can be done simply with a hand grinder, parallels, and some high spot blue, and finished up with a file and some stoning so that the edge will be flat, and superior to anything you will get on the machine, and will be finished (trust me, have done lots of this) before you can get the set up made (lots of indicating, finding parallels, and shimming) in any machine, CNC or not. Old timers did this kind of stuff on a regular basis, and the Japanese still do. Yet the customer wants it done on CNC, so thats how it will be done, fortunately the customer is willing to pay for this.

I can site several more examples, but hopefully it makes the point.

oldtiffie
02-02-2010, 06:41 AM
Give the customer two quotes:

1.
CNC-ed: $$$$

and

2.
any other way that suits you.

Let the customer decide - and have him accept the quote - in writing.

Perhaps the customer has had other quotes for CNC and is just trying you out or perhaps using your quote and work as a bargaining chip else-where.

Evan
02-02-2010, 07:03 AM
I just got my CNC vinyl cutter up and running. It's an old HP unit but holy cow is it fast. It's all servos, not steppers and can cut at 32 inches per second. That is almost 2000 inches per minute.



Yet the customer wants it done on CNC, so thats how it will be done, fortunately the customer is willing to pay for this.


You know why? It's because CNC is how you make things from Billet.

jackary
02-02-2010, 07:29 AM
Hi toolmaker76
I think what you are trying to get across is the belief that only CNC can produce the desired result and this was not possible before CNC. I think the greatest difference between manual and CNC production is the skill factor. CNC is essentially a de-skilling process removing the requirement for a skilled operator requiring extensive training and a minimum of an aptitude and intuition to control a manual machine to produce the desired result. In short an artisan. There are also cost savings to be made by having less skilled operators and computers that have inbuilt programs etc. Slightly OT but similar is CAD design and drafting compared to manual drafting. Good manual design and drafting required skill which was obvious as soon as you looked at a drawing.
The skill and precision in a CAD drawing is provided to a large extent by the computer system. Because even a bad draftsman can achieve a neat presentation in a CAD drawing/design it very often hides the lack of discipline/skill/experience that is there, at least to the inexperienced eye (ie. Management). The management are still trying to get a thousand monkeys with typewriters to write Shakespeare on the cheap because today there is little requirement or understanding of the basic skills.
Alan

vincemulhollon
02-02-2010, 08:00 AM
If you get the first part right, you WILL NOT screw up on any of the rest. This is very helpful if you've been working continuously for 6 hrs and are starting to get pretty tired.

Of course no one on this board admits to making scrap, but out in the real world I've heard the worst possible scenario when making a part is screwing up step #231, meaning you have to start all over again manually at step #1 and then manually do 230 steps to catch up to the mistake at which point you'll be even more tired and more likely to make the same mistake again. Oh well it builds character. With CNC you put in a breakpoint or truncate the g-code after step #230, re-run the program, and then manually figure out what is wrong with step #231, then finish it off.

Sarbatche
02-02-2010, 08:03 AM
Hm. The machining rate in the Navy has a special job code (NEC) for CNC operators, which is obtained after specific schooling. Generally, however, CNC schooling isn't offered to junior Sailors unless they've already gotten a firm grasp of manual techniques. As in, having already gone through our 'pipeline' school that teaches advanced precision grinding, heat treatment, etc...

What I'm getting at is this: Navy machinists and our clients put a preference on conventional machining and only use CNC for the real fancy shapes or those orders of umpteen special bolts.

johann ohnesorg
02-02-2010, 08:07 AM
Toolmaker76,
I get where you are coming form. I´ve seen very simple parts run on machines that cost a lot per hour. Could have been done with a drill press, a few drills and a reamer plus a jig on the cheap. CNC in this case was not to the benefit of the customer but it kept the machine with the huge cost overhead busy.
On a manual machine, it could have been done by a low skilled operator on an hourly base. Or by someone from the company who´s idle right then.
Same thing with pneumatic or hydraulic machines or second operation lathes. If set up the right way, they crank out parts without stop. Again, operated by a low skilled operator=cheap. But pretty unflexible. This can be overcome by dedicated setups. With cheap tooling, vises and chinese or cheap second hand machinery at hand jigs can be set up for a dedicated operation and be left in storage until you need it again.
A friend of mine uses two horizontal mills with table feeds and endstops for second operation machining of plastic and aluminum parts for his buisiness. One machine runs, the other is unloaded/loaded set to operation. Since both machines have approximately the same cycle time for work and load/unload, those machines are very productive and have earned their (scrap) price many times. All the smartness of the machine is hidden in the jig. And in my friends head. He has a certain "make do" attitude and could not afford the automatised solution they offered him back then. When he bought the two machines the machine dealer asked him what he wants with those horizontals, no one wants them anymore because they are no good at all. The price per machine was approximately equivalent to one afternoon of heavy cutting on a CNC machine. I´ve spent a few evenings on those two beasts to help out when it was tight, they keep you really busy. But what the heck, he payed in beer, BBQs and favors back then.

My guess is that a lot of operations merely assemble their parts and don´t have a dedicated workshop anymore. Therefore, they have no understanding of the manufacturing process. And since CNC can do anything they imagine, they tend to see this as the only or easiest way to get things done.

I´ve seen huge milled surfaces on parts that had no function at all, the guy just drafted them this way without thinking or so they look nice. I´ve seen CNCed parts in huge batches that screamed and begged for a casting and only a few milled and spotted surfaces. Just by counting the parts and guessing costs (I order and quote a lot of parts and usually hit the end price in a 5-10% margin just by guessing) I figured that half the costs could have been saved if they would not mill it out of a block of aluminum in the beginning. :rolleyes: Simple math can easily sort out the breakeven for such solutions.
As it seems, for some operations cost awareness or simplification and lower different parts count is not a number one topic.
But what do I know, one of our customers made parts out of steel, gave them away to have them plated and always whined about the costs and the time involved. When I asked him why he won´t make them out of stainless in the beginning to get around the electroplating he looked at me like I was crazy. I told him we can do the part for 3 euros more per part if we used stainless instead of cheap cold rolled and he told me what he usually pays for a small part run at the electroplating facility. It was a cost and timesaver.

Cheers,
Johann

Evan
02-02-2010, 09:03 AM
Think about this for a minute.

CNC milling machines didn't replace the the manual milling machine. They replaced the shaper. The shaper is a semiautomatic machine. One good shaper operator can run half a dozen machines at once depending on the job. Some shapers near the end of the "shaper era" were nearly as capable as a CNC machine except it was all done mechanically. The CNC metalworking machine is a natural conceptual progression from the automatic metal shaper. It just happens that a 3 axis system is best suited for CNC control so the vertical mill is a natural platform for that purpose.

John Stevenson
02-02-2010, 09:12 AM
Think about this for a minute.

CNC milling machines didn't replace the the manual milling machine. They replaced the shaper. The shaper is a semiautomatic machine.

No they replaced the tracer mill, a shaper cannot do blind pockets and that is why CNC mills look like manuals with motors and not look like shapers.

Just as the CNC lathe replace the tracer lathe.

.

masondixonmetalworks
02-02-2010, 10:05 AM
I feel that CNC and manual machining have equal and seperate merits, but are both needed, and should be utilized. They are just seperate tools, in the same box so to speak.

I'm learning machining, backward, so to speak. All my machining expierence comes in the form of CNC. I love what I do for work, and the field is ever expanding, so there is always something to learn, which keeps things from getting stagnant.

However, for years I wanted to know how to manualy do the things that the machines were doing. I have an interest in old school methods and trades, and felt that I was cheating, having by-passed the predecessory methods. It took a while, but I finally managed to get my own equipment, so I could put to use, what I had taught myselt and learned, and a chance to discover more.

There is something to be said for, not just manual machining, but for actual trade work and skills. They should be preserved, used, handed down, taught and shown. If we let them die, we let a piece of our heritage and ourselves die.

I know this does'nt really address the original point, but just know, not all of us young-uns disregard what you old-schoolers have to say or do. Contrary to that, I wish I had a mentor to learn from, but I learn and do what I can, so I may carry the torch in some regard.

DR
02-02-2010, 10:23 AM
.................................................. .......................

this is just to take off a small high spot. It can be done simply with a hand grinder, parallels, and some high spot blue, and finished up with a file and some stoning so that the edge will be flat, and superior to anything you will get on the machine, and will be finished (trust me, have done lots of this) before you can get the set up made (lots of indicating, finding parallels, and shimming) in any machine, CNC or not. Old timers did this kind of stuff on a regular basis, and the Japanese still do. Yet the customer wants it done on CNC, so thats how it will be done, fortunately the customer is willing to pay for this.

I can site several more examples, but hopefully it makes the point.




I can't comment specifically on your part without knowing more about the situation.

I do know my customers want parts CNC'd for several reasons.

Many of the customer parts are appearance + plus function where appearance is almost as important. Just a simple reducing a bar diameter up to a shoulder on the lathe, the CNC can produce an even cut pattern right up to the shoulder part after part to close tolerance. Filing an appearance part is not an option. Same with CNC milling, the appearance is far better than with manual milling.

Even when the customer says only one prototype part, we both know it's likely they may need another with a bit of change. I always save the program and tweak it until we know the design is firm.

And, probably the most important reason is CNC is so much less expensive for the vast majority of parts.

BTW, it's interesting to look back 20+ years when I bought my first CNC. At that time you had to do a big sales pitch to convince customers CNC wasn't the expensive way.

Carld
02-02-2010, 10:48 AM
I tend to think they are a replacement for the automatic screw machines a little more than the tracer mill. Both are replaced by the CNC so I guess it's moot.

toolmaker76, I too understood what you meant and I agree with your opinion. I think CNC has it's place but so does manual machines. For one thing, home shops and part time paying shops can't afford CNC and the necessary tooling. As I said I worked around them all the time but did not get trained for them and really didn't want to but if I were running a full time shop I would get the training and buy one or more.

The fact is as a part time shop I can't afford to have a $10,000 machine sitting around doing nothing. Whether you use CNC or manual machines has to be a cost factor, not how great they are. It doesn't matter how fast I can do a part if the machine and tooling is beyond a realistic cost. Even if I were running a full time shop I probably wouldn't use the CNC for everything and the shops I worked in didn't use them for everything either.

I know that a lot of people have a strong feeling that CNC is the only way to go but that is not really true and the main factor is the cost of the machine and tooling required for your situation.

This happens everytime you have a CNC versus manual. Each party lines up on opposite sides and derides the other with no thought of practicality of use. The real issue is which one is practical for the job at hand.

BobWarfield
02-02-2010, 11:12 AM
I'll post another thread, "Using a CNC like a mill with DRO and Power Feeds."

It's incredibly easy to learn just a couple commands to do it. At that point, hard for me to see why there is any advantage to a manual machine, because you literally can run the CNC like a manual.

Where there are manual machines, it seems to me the reasons are simple:

- An extra Bridgeport is about like a drill press relative to the cost of an extra Haas or Fadal CNC. It's cheap, it doesn't matter if it isn't used much, you may have already had it kicking around, and you might use it while the CNC's are busy.

- Where lathes are concerned, there are a lot of very simple parts like bushings and such you can just bang out real quick on a lathe. One offs like that are much more marginal advantage to the CNC. Mill once offs, if you have a CNC, I don't see the Bridgie advantage.

Cheers,

BW

DR
02-02-2010, 11:15 AM
.................................................. ........

The fact is as a part time shop I can't afford to have a $10,000 machine sitting around doing nothing. Whether you use CNC or manual machines has to be a cost factor, not how great they are. It doesn't matter how fast I can do a part if the machine and tooling is beyond a realistic cost. Even if I were running a full time shop I probably wouldn't use the CNC for everything and the shops I worked in didn't use them for everything either.

.................................................. .....................



You know, we may soon be turning the corner on cost of manual versus CNC.

Priced any high quality manual lathes lately?

10EE? They were over $50K 15 years ago.

Hardinge HLVH? I think they only make on special order, if at all. $40K+?

A brand new Haas TL1 at around $30K fully equipped. You'll spill more money on the way to the bank with that than either of the above will make in a day.

Evan
02-02-2010, 11:22 AM
No they replaced the tracer mill, a shaper cannot do blind pockets and that is why CNC mills look like manuals with motors and not look like shapers.


You are looking at it from the wrong end John. It doesn't matter what the shaper can't do. What matters is that a CNC mill can do everything that a shaper CAN do which is why they don't make shapers any more. The most important part of what the shaper can do is run automatically.

People think they were too slow. Not true at all, especially if one person is running several at once. My 16" shaper will peel off metal at a rate equal to any similar weight and power milling machine and faster than most.

bborr01
02-02-2010, 11:45 AM
Evan,

Darn it, you beat me to it with the BILLET thing.

A lot of it has to do with marketing.

CNC + BILLET = SALE

Brian

Carld
02-02-2010, 11:54 AM
DR, I have visited and talked with many paying shops and home machinists and it's rare to see them with a Hardinge or 10EE or any of the other high priced lathes such as those. Most have common brand USA, European or Asian lathes or mills.

When a home shop or small full time shop or part time shop like me looks at the price of the Hardinge, 10EE, CNC or any other high price lathe or mill they ask themselves, do I really need that. The answer is usually NO.

I have a Taiwan lathe and mill made in the middle 1980's and I can turn out very accurate work on either of them even if it takes longer than a CNC. Why should a person pay for something they don't need. To keep harping on the issue that everyone NEEDS a Hardinge, 10EE or CNC to make money is ridiculous and without common sense.

I am not picking on you, I am picking on those that think that is the only way to go. It's NOT the only way to go unless your in full time business and can keep the machines running at least an 8 hour shift and many times you have to keep them running at least 16 hours to pay for them. The shop I worked at with a lot of CNC machines said they had to keep the machine working a full 8 hours to make the payment and make a profit. I doubt things have changed from the middle 1990's to now, you still have to pay for the machine and have work for it or you will go under.

There is a common sense approach to everything and common sense says if in business you have to consider the costs of operation. If a small shop or home shop the rule still applies so cost and return is of great importance to a thinking person.

As I said, everyone lines up on opposite sides and derides the other side. I am not deriding either side but trying to point out that cost of operation HAS to be part of the reason to go manual or CNC or any of the expensive high quality or even both. It's not a simple thing and each machine has it's good and bad points.

kf2qd
02-02-2010, 11:54 AM
Toolmaker76,

I´ve seen huge milled surfaces on parts that had no function at all, the guy just drafted them this way without thinking or so they look nice. I´ve seen CNCed parts in huge batches that screamed and begged for a casting and only a few milled and spotted surfaces. Just by counting the parts and guessing costs (I order and quote a lot of parts and usually hit the end price in a 5-10% margin just by guessing) I figured that half the costs could have been saved if they would not mill it out of a block of aluminum in the beginning. :rolleyes: Simple math can easily sort out the breakeven for such solutions.
Johann

I have worked with some of those castings, the reason that some parts are no longer castings is because it can be difficult to get a good oiltight casting, and the billet piece is both oiltight and stronger. The old way was to use a casting and live with the weaknesses of the casting, now they can get it from billet and eliminate other workarounds to compensate for the weaknesses. From a machining standpoit - I would much rather use billet as tool life is better, and often a bunch of time can be wasted trying to get the casting lined up right because of the variability of castings.

johann ohnesorg
02-02-2010, 12:04 PM
As soon as more features on a part are geometrically closely related, CNC wins hands down. But in the real world a huge amount of parts are used that have only one or two related features that can be manufactured in one single setup or with tolerances that can be guaranteed by a jig.
This is where the manual machine can be faster or more cost effective. If I can do primitive parts inhouse, I do them inhouse. That way, I only pay my overhead and I "steal" the manufacturing time from idle time the workers have anyhow. Otherwise, I have to pay other peoples machines and overhead.

Cheers, Johann

johann ohnesorg
02-02-2010, 12:42 PM
nch of time can be wasted trying to get the casting lined up right because of the variability of castings.

I had castings made with part weight of 40 kilos, would have been around 110 kilos from stock. I would have thrown away 70-80 kilos of raw stock already for nothing, tediously carved out of our part.
Our casting operation is able to hold millimeter tolerances on this parts and their surfaces are great, they do far better than they guarantee.
Sure, the form did cost money up front but their process is first class and so are their results. Even for prototype work with huge parts, I would ask them for a lost foam casting and then throw their part on the machine.

I also had problems with a bad foundry before, they achieved all you mention: sloppy fit, bad surfaces, inclusions and small bubbles in the casting because of neglected melt. And for sure they were not able to hold an agreement on a deadline, not even if their life had depended on it. But since I found all this in one place, I guess this is more a problem of philosophy and craftmansship then a problem of the casting process.

Evan
02-02-2010, 01:09 PM
Casting is perfectly controllable. Aluminum alloy die casting is net shape for most applications with the only machining required for precision placements of bearings and other components. Just look at the chassis of a hard drive.

beanbag
02-02-2010, 01:28 PM
What I get tired of dealing with is the attitude that it is not right if it is not done on CNC, or that it can't be run as part of a production setup without doing it on CNC. There are some things that are not appropriate to set up with a CNC, yet some customers have the belief that it is a matter of fudging if the job wasn't programmed and run on a CNC machine.

I think the main reason for this is that the customer simply doesn't trust you to get the part right. I don't necessarily mean in a bad way, more like "skeptical". If he wants you to drill a bunch of holes at seemingly random locations, and needs 5 of these parts, and isn't able to measure the hole placements himself for all 5 parts, then how will he know that you didn't mess up one of the parts, and place the hole at x,y=1.080, 1.008 instead of 1.008, 1.080? Insisting that the work be done on CNC ensures that at least all the parts will be identical.

More generally, CNC work usually has at least a lower bar on just how bad you can mangle up the part. Back when I was looking to get end mills sharpened, I always asked if they were going to do it manually, or on one of those spiffy 5 or 7 axis machines. I've heard of manual end mill sharpeners doing a poor job, but I have never heard of a cnc sharpening shop messing up. At that time, I had very little knowledge of end mill sharpening, so I didn't have any shops that I "trusted".

In short, this CNC vs manual thing is not an issue among machinists who have used both, it is between shops and skeptical customers.

camdigger
02-02-2010, 01:36 PM
It's a buzz word thing among many potential clients. The Teutels on OCC have them, so they must be the thing we need. Production shops have been leaning toward numeric control for decades, so if we want you to "Produce" something, it must need to be CNC'd, right?

It's all about perception and education. Not all customers are as savvy as they'd like to think.

As for my opinion, I think it is a matter of horses for courses. CNC, robotics, and manual machines and processes all have their place in machine shops and fab shops. And regardless what else I've heard, manual machines will always have a place in the repair shops.

BobWarfield
02-02-2010, 02:16 PM
That customer perspective is no different than the customer that picks the clean shop with the row of shiny new looking macines over the old shop. We've all seen the shiny shops that can't do good work and the grungy shops that accomplish magic.

It's really not an indicator of much, but the customer has to make a decision based on something, so they do.

OTOH, unless I need something really special and know from talking to other customers the grungy shop has a unique advantage, I'd probably figure the shop with the CNC is more "serious" about being in business so they invested to get one and learn how to run it.

It doesn't take much. No end of guys with CNC's in their residential garages manufacturing something or other.

Cheers,

BW

Mark Hockett
02-02-2010, 03:48 PM
Cost of CNC machines has come up in this thread a few times. I paid $1250 for my Milltronics knee mill and my two friends paid less than $2000 for theirs within the last two weeks. Compare that to the $4400 I paid for my used manual mill and the CNC wins out. I have made more than I paid for my CNC in two days, I cant say that about the manual mill. The lowest price I have seen to date on a used Haas TL-1 is $9000. That might be high for a hobby guy but if you plan to do pay work on the side its cheap. If you compare the price on new lathes the Haas is a better choice. A new TL-1 with a tail stock is $24,800, a new 16 X 40 Southbend is $19,600 and to do some of the stuff that you can do on the Haas you will need to add a $1150 taper attachment and a $1000+ radius attachment. If you look at some of the better manual lathes like the Clausing the cost will be more.

Toolguy
02-02-2010, 03:59 PM
CNC is great, but if not used correctly, it's just a faster way to make scrap.

toolmaker76
02-02-2010, 04:29 PM
I think most of you understand my point. I wasn't making a point, CNC vs. manual, just the attitude these days that manual can't be as good.

Had a situation my first day in the last shop I worked, all the CNC mills were tied up, and my job was to make a replacement toggle link for one of the area factories. There were two bored holes and two big outside radii. No problem, found a boring head and a rotary table and made the part. Given, CNC would have been much faster had it been available, but it wasn't. I looked up several times to a crowd of people watching who had never seen a rotary table in use! A relatively simple example, I realize, but the customer got his part in a timely manner!

I have 30+ years experience, never have had to chip flint to make arrowheads, but feel like I came on the scene shortly after that! Most HSMers won't have the expensive CNC stuff, although like was mentioned it is getting cheaper, have seen some deals myself lately. The point is that a skilled machinist can do quite a bit without it, and the bottom line is if its right its right, no matter how it was done!

motorworks
02-02-2010, 04:55 PM
A little late in the post and have not read them all but here goes:

I run a one man shop. 3 manual lathes and two manual mills
One cnc mill (bp-mach3) and one Cnc lathe 11'' mach-3
I love making things manually-by hand, but the truth is that's not were it is today in a real shop.
I have a ship in today. They are usually here only long enough to unload.
They usually emai a list of parts, but most times they tell me just as she lands.
Not big lots, but 4 of these,6 of those, 10 of this, etc. adds up.
Without cnc and Cad-Cam I could never make a lot of thses parts before she sails again. i.e. I would be out money......

Turning handles my be 'romantic' but in the real world romance costs money
and money is what you will make on a cnc machine. :)

John Stevenson
02-02-2010, 05:29 PM
The difference between billet and castings doesn't need to be so wide with CNC.

Old way was manually make a pattern, have castings done and only machine the surfaces needed on manual machines. Big saving in metal costs, less machining time versus the cost of the pattern.

New way is to CNC out of a solid billet, big saving in labour versus higher material costs.

But what about using both methods, get the CNC to churn a pattern out using cheap materials and low tolerances.

http://www.stevenson-engineers.co.uk/files/pattern1.jpg

One pattern still on the machine and a previous made one to the side. Made from glued up layers of scrap MDF cut with a wood router cutter with a draft angle. If a bit of forethought is put into the pattern it is often possible to use one pattern for right and lefthanded parts.

The pattern then goes to the foundry and as many as needed are cast off it.

http://www.stevenson-engineers.co.uk/files/pattern3.jpg

Casting fully machined as regards mounting points and bearing surafces.

Pattern making time plus machining time is far less than machining two billets from solid, material costs are at least half and any subsequent parts will return an even greater saving.

I don't know about you but this part looks better to me that one out of billet covered with tooling marks all over.

.

Mcruff
02-02-2010, 05:34 PM
No they replaced the tracer mill, a shaper cannot do blind pockets and that is why CNC mills look like manuals with motors and not look like shapers.

Just as the CNC lathe replace the tracer lathe.

.
Agreed!
In fact our large CNC at work was born as a Droop & Reins tracer mill, converted to NC in the mid 70's and then converted to CNC in the early 80's and refitted around 1996 to a more modern controller.

John Stevenson
02-02-2010, 05:56 PM
You are looking at it from the wrong end John. It doesn't matter what the shaper can't do. What matters is that a CNC mill can do everything that a shaper CAN do which is why they don't make shapers any more. The most important part of what the shaper can do is run automatically.



The manual mill killed the shaper by doing what the shaper could and more, the automatic part of the shaper was duplicated by power feeds, in some case in all three axis [ not at the same time ] which the shaper can't do.

Then tracer units were fitted, often with 2 and three heads, again something the shaper didn't do.

This them progressed to the aerly CNC like the Moog with hydraulic controls then morphed into the 2 axis CNC like the Protrack then into full 3 axis, then into VMC's

They never replaced the shaper because it was already dead at this point.

.

Kibby
02-02-2010, 06:25 PM
My feelings on CNC are this: CNC is nice, and I would love to learn it, but I feel that the learning curve and the expense of machinery and software would be two very big obstacles in the way of home workshop happiness. This IS a home-workshop forum, yes? :p

I would love to believe that for every reason CNC is a religion, I believe manual machining to be a religion unto its own. When you dream of something in your head - you see it in your mind's eye - you translate it through your hands into your work. I think that unless I was mass-producing something, a CNC would only keep the human element out of my work.

lazlo
02-02-2010, 06:35 PM
With a machine that has decent conversational programming its way faster than a mill.

I've been to several of the machine shops in Austin, and they're all running almost entirely CNC. They usually have a Bridgeport and an old lathe somewhere, but the vast majority of their work is CNC.
MickeyD is making a living as a machinist in Austin, and he doesn't even own a manual mill :)

Personally, I have little interest in CNC -- I do manual machining as a hobby because it's a craft and skill, and vastly different than what I do for a living (design microprocessors).

John Stevenson
02-02-2010, 06:39 PM
Kibby,
For some people making CNC's has now become their hobby, for others CNC is just a means to an end because they are more interested in the finished part be it for a vintage bike / car or RC toy.

At the end of the day it's just a tool.

.

lazlo
02-02-2010, 06:44 PM
At the end of the day it's just a tool.

But what Kibby is saying is very apropos to the OP: CNC is just a tool, but doesn't require any art, and much less skill, to operate.

Or put another way, as is often noted on PracticalMachinist, many CNC operators couldn't run a lathe if their life depended on it. Manual machining is an old-school hobby. Very, very few young people are taking-up manual machine work as a hobby or profession.

Within a half generation, virtually no one will know how to operate a manual machine.

camdigger
02-02-2010, 06:46 PM
The difference between billet and castings doesn't need to be so wide with CNC.

Old way was manually make a pattern, have castings done and only machine the surfaces needed on manual machines. Big saving in metal costs, less machining time versus the cost of the pattern.

New way is to CNC out of a solid billet, big saving in labour versus higher material costs.

But what about using both methods, get the CNC to churn a pattern out using cheap materials and low tolerances.

http://www.stevenson-engineers.co.uk/files/pattern1.jpg

One pattern still on the machine and a previous made one to the side. Made from glued up layers of scrap MDF cut with a wood router cutter with a draft angle. If a bit of forethought is put into the pattern it is often possible to use one pattern for right and lefthanded parts.

The pattern then goes to the foundry and as many as needed are cast off it.

http://www.stevenson-engineers.co.uk/files/pattern3.jpg

Casting fully machined as regards mounting points and bearing surafces.

Pattern making time plus machining time is far less than machining two billets from solid, material costs are at least half and any subsequent parts will return an even greater saving.

I don't know about you but this part looks better to me that one out of billet covered with tooling marks all over.

.

If your local foundry is set up for lost foam, that may be an option for short runs too. Machine up a foam pattern and send to foundry where it is submerged in sand and cast. Burying a pattern in sand should be less $ than the cope/drag method.

BobWarfield
02-02-2010, 06:52 PM
Or put another way, as is often noted on PracticalMachinist (predominantly professional machinists) many CNC operators couldn't run a lathe if their life depended on it. Manual machining is an old-school hobby. Very, very few young people are taking-up manual machine work as a hobby or profession.


Really?

Hmmm. Really?????

So then anyone running a CNC is just an operator, and it really all is in the wrist after all, since it's all only a matter of just pushing that green button or turning the handwheel that separates the artist craftsman from the dumb button pusher.

There are no skills, no knowledge, and no art whatsoever to anything CNC.

That really is a religion it is so far from being factual.

Cheers,

BW

lazlo
02-02-2010, 06:56 PM
There are no skills, no knowledge, and no art whatsoever to anything CNC.

There's skill and knowledge required, but no art in operating the machine.

Manual machining is art and requires a lot more skill. Anyone disagree?

beanbag
02-02-2010, 07:22 PM
There's skill and knowledge required, but no art in operating the machine.

Manual machining is art and requires a lot more skill. Anyone disagree?

I disagree. Just because something is harder to do, takes longer, results in poorer quality work, and has more limited capabilities does not mean it is art.

One could say that for you, manual milling is quaint and theraputic in an old skool kind of way, and I mean that in a totally condescending manner :)

Carld
02-02-2010, 07:32 PM
beanbag says,

Quote:
Originally Posted by lazlo
There's skill and knowledge required, but no art in operating the machine.

Manual machining is art and requires a lot more skill. Anyone disagree?

I disagree. Just because something is harder to do, takes longer, results in poorer quality work, and has more limited capabilities does not mean it is art.

------------------------------------------------------------------------
beanbag, what makes you think manual machines turn out poor quality work?

I think your absolutely wrong there. Maybe you can't do quality work on a manual machine but everything I do is quality work on my manual machines even if it does take longer and time is not an issue for me or my customers.

The reason I am doing the work for one customer is they had several shops, both manual and CNC do the work I am doing now and none of them produced the quality I do. For that reason he gave me all his work. He gives me the part and I do the modifications to it. He don't want someone to scrap parts that costs from $100 to $1000 and I don't.

beanbag
02-02-2010, 07:37 PM
beanbag, what makes you think manual machines turn out poor quality work?


Well, unless you can tell me a case where something can be done better manually than CNC, then I would assert the relation

manual <= CNC quality

Any CNC shop can botch the quality, no question

If YOU had a CNC, the quality of your work would only improve

John Stevenson
02-02-2010, 07:45 PM
CNC- the new religion?


If you want a new religion how about knurling a co-ax ?

.

Carld
02-02-2010, 07:48 PM
That's not what you said originally, you said and implied that manual machines CAN'T do quality work and that is absolutely WRONG.

Manual machines and CNC can do work equal in quality. With a CNC the quality is with the programer and his tooling selection. With a manual machine the quality is with the machinist, his tooling and his skill.

Two different process can get to the same quality but the manual machinist has to work for his quality every part and the CNC man gets the same thing everytime just standing there watching the machine. I enjoy the challenge of manual machining and don't see any challenge in CNC for me or anyone else.

I knew this thread would end up being contentious and derogatory and why is it that CNC operators think they are better than anyone else.

If I had a CNC the quality would not improve, but the job would be done with no challenge on my part.

beanbag
02-02-2010, 07:51 PM
That's not what you said originally, you said and implied that manual machines CAN'T do quality work and that is absolutely WRONG.


No, I said that they did worse quality work than cnc, whereas I should have said equal or worse. Worse than perfect can still be pretty good ;)

Carld
02-02-2010, 07:59 PM
And I say manual machines don't do poorer quality work than a CNC. The quality of the work from either one depends on the operator and his skills, the machine is indifferent and don't know good from bad.

I said before, if I were running a full time shop I probably would buy a CNC lathe and mill but ONLY because of the time element, NOT the quality of work being better than manual machines.

Evan
02-02-2010, 08:03 PM
John, milling machines and shapers coexisted side by side for many years. There are shapers with tracers and they are still made too. The main market is south and south east Asia where cnc is not a practical or reliable alternative to the shaper. It's no coincidence that the first numerical control mill was developed just after WWII and on public sale in the 50's. Within 10 years all sales of shapers in the west had ended as CNC took over the jobs that only a shaper could do easily until then.




Metal shapers and planers were the work horses of the machine shop for many years. While they have been replaced by the modern CNC machines in most shops, they can do seemingly impossible jobs with inexpensive tool bits.
http://shopdawg.com/SDRP-2003-Shaper.htm

Evan
02-02-2010, 08:12 PM
And I say manual machines don't do poorer quality work than a CNC.

CNC beats manual hands down when it comes to repeatability. It is easy to obtain repeatability to .0001" with an ordinary CNC mill or lathe. If you want a run of parts to be all the same for maximum interchangeability automatic machining is how you do that whether it be mechanical, electromechanical or computer driven.

lazlo
02-02-2010, 08:35 PM
Manual machining is art and requires a lot more skill. Anyone disagree?I disagree. Just because something is harder to do, takes longer, results in poorer quality work, and has more limited capabilities does not mean it is art.

You say you disagree, but then re-state my premise :) : manual machining is much harder and takes a lot more skill to replicate the results of a computer-controlled machine.


One could say that for you, manual milling is quaint and theraputic in an old skool kind of way, and I mean that in a totally condescending manner

Some high-end knife makers, like Angel Sword in Austin, have VMC's. They use them to make mid-range knives and swords. But their key market segment is hand-made swords and knives, forged from raw materials. They make a hand-forged, pattern-welded S7 Super Katana that sells for $8,000.

Is that quaint and Old School? Perhaps. Art? Absolutely.

http://www.angelsword.com/photos/knives_daggers/dw132-1328a.jpg

DR
02-02-2010, 08:38 PM
If your local foundry is set up for lost foam, that may be an option for short runs too. Machine up a foam pattern and send to foundry where it is submerged in sand and cast. Burying a pattern in sand should be less $ than the cope/drag method.

I recently had some aluminum parts investment cast using the lost wax method.

We supplied the foundry a CAD file (this was a hollow part with passage ways). They used their CNC rapid prototyping machine to make the wax model.

beanbag
02-02-2010, 08:46 PM
And I say manual machines don't do poorer quality work than a CNC. The quality of the work from either one depends on the operator and his skills, the machine is indifferent and don't know good from bad.

I said before, if I were running a full time shop I probably would buy a CNC lathe and mill but ONLY because of the time element, NOT the quality of work being better than manual machines.

What if somebody asked you to make an ellipse for a scientific demonstration, at the quality of work was defined as how closely you could match the exact shape?

bborr01
02-02-2010, 08:48 PM
I recall about 15 or 20 years ago having this same debate at work. In our tool room we had 2 VMC's and about 15 Bridgeports or clones.

One day the general foreman told me if it was up to him he would sell those damn cnc's and buy a half dozen more Bridgeports, then we could get some work done.

I knew right there it was time for him to retire.

When I retired 4 years ago we had 4 cnc's and maybe 10 B'ports.

The cnc's produced several times the work that the manual machines did.

They also did it with a lot less labor and with a lot better quality.

The operators did a lot of the programming while they were running the last job.

The cnc's are not going away.

Brian

DR
02-02-2010, 08:54 PM
CNC beats manual hands down when it comes to repeatability. It is easy to obtain repeatability to .0001" with an ordinary CNC mill or lathe. If you want a run of parts to be all the same for maximum interchangeability automatic machining is how you do that whether it be mechanical, electromechanical or computer driven.

.0001"? Or .001"? With tool wear we figure about .0002"+/- is the best we can do for a long run. And, that requires close watching. Anything much closer is almost too hard to accurately measure anyhow.

.001"+/- is child's play on the CNC lathe.

beanbag
02-02-2010, 08:58 PM
You say you disagree, but then re-state my premise :) : manual machining is much harder and takes a lot more skill to replicate the results of a computer-controlled machine.


You threw in an extra clause there, namely "replicate the results of a computer-controlled machine". I can also either walk 100m or do a handstand and move 100m and the latter takes more skill and is harder, but so what? IOW, I don't assign any bonus points for doing something the hard way. CNC lets you do MORE things, and it takes new skills to do those new things

Also, art involves curly frilly things, and CNC's can do that while manual machines can't. :)

As for your example of the knife being art, my friend and I had one of those "what is art and why do people pay for it" discussions a while back, and I was of the opinion that you are paying for the smugness factor of somebody having thrown a lot of hours at it.

BTW, why aren't you driving an E30 instead?

BobWarfield
02-02-2010, 09:13 PM
beanbag says,

Quote:
Originally Posted by lazlo
There's skill and knowledge required, but no art in operating the machine.

Manual machining is art and requires a lot more skill. Anyone disagree?

I disagree. Just because something is harder to do, takes longer, results in poorer quality work, and has more limited capabilities does not mean it is art.



I too will disagree.

Almost everything you want to call "art", "skill", or any other exalted term on manual applies to CNC EXCEPT turning the silly handwheels, and many manual machines have power feeds, so where is all that art?

The CNC guy still has to know setups and fixturing, which are a huge part of the game. He still has to know feeds, speeds, and a whole host of tooling knowledge. He still has to know the art of measurement. He may not need to do layout because he has CAD, but so what, many manual machinists use it too. Has that eliminated their "art"?

Are there those here who will argue they can spin a handwheel by hand to produce a better result than a power feed? Can you position your table more closely than the CNC? Do you prefer not to use a DRO because your eye is sharper?

Surely not, but that is the sort of thing you have to argue to go down this romantic notion of art.

There are certain aspects of the analog mechanical world that may not be required, but really, is spinning the rotab to generate an arc what you want to call "art"?

Not me.

And those arcana are offset by important skills and knowledge that are very unique to CNC. All the tricks of getting 3D profiling to come out well are not just a matter of pushing that little green button. There is a tremendous amont of skill and knowledge needed.

The CAM program doesn't do the half of it for those that are thinking they do. Most are shocked at how much the machinist/programmer has to tell that CAM program to get it to do something smart instead of something stupid.

Just as much art there, if indeed there is any art. Turning the handwheels has little to do with making knives by hand either. Half that game is also a function of wanting to be able to protect your "art" by saying, "Oh, that was made by hand and not by a CNC." Therefore it is scarce. Therefore it is valuable. On and on. We see it with firearms and cars that have matching numbers and all the rest. That's just testosterone talking.

Whether or not you could even tell the difference in any goood way is an altogether different question. Lots of silly marketing goes with "art" just like everything else where people are competitive.

At best, this is craft or skill, and not art anyway. Art is about unusual creativity that communicates a message, and you can exercise that equally as well on both manual or CNC machines.

If you think CNC cannot involve art, or comes about easily by souless idiots pushing the green button with no effort, you don't know CNC:

http://www.youtube.com/watch?v=RnIvhlKT7SY

Cheers,

BW

Doozer
02-02-2010, 09:21 PM
I used to work for this boss that had lots of CNCs. He was trying to bore a 1" hole in Rc 58-60 4150 steel. Tolerance +.0002/-.0000. He was circular interpolating with a 3/4" carbide end mill. Obvioisly he was having trouble holding roundness. After lots of yelling and farting around, I told him to slap an old fashoned boring head in the machine. That would eliminate any reversal error from screw backlash. He barked something about how great his CNCs were and that a boring head was a stupid idea. Why he insisted on pre-hardening everything, I will never know. Working there was like working for OCC and madd dadd. I don't work there any more.

--Doozer

spope14
02-02-2010, 09:30 PM
I have run everything from screw machines to turret lathes, horizintal mills to Bridgeports, Natco multi spindle drills, you name it but for a shaper. Been doing CNC since I had to punch in code on black paper tape on a Brown and Sharpe 40 tool machine center and a Hurco "answering machine tape" mill programmed through a TRS (Trash 80) 80 computer using ascii and goofball basic type commands.

Grew up with CNC, also grew up with Manual and tool making skills. I still teach manual, gets a "feel" for the cut and makes you think about the cut, and you observe the cutter up close and personal while it cuts. many of our CNC shops send me students to learn this. This said, they also send me the students to learn manual skills because I DO relate these skills directly to CNC and how they apply in programming, speeds/feeds, set-up, and how chips should look and quality achieved.

Heck, a couple of years back, I even started teaching grinding drills and lathe bits again - kind of have to so the CNC operator knows what is really going on, and what tool selection really means. Also, with some of the current tooling coming out - like crappy ground drills - it helps identify the problem on first sight, not after ten drills/inserts/end mills gone in the pack of ten.

My home shop has both.

This said, manufacturing is going the way of CNC. Oh yes, I am well aware of the afghans who fight with home made arms made in little home forges and filed out, but I mean real mass production manufacturing and Research and Development manufacturing of some real tricky stuff that even the toolmaker could not truly imagine as making "off" by the 100 lot.

WWII had some real intricate items, no doubt, but looking at some of the simpler parts of a harrier or YF22, and the function of these compared to the older aircraft - well WWII did not have the harrier, though the initial thoughts were there, so what was done was really neat, and the Harrier is evolved from what was, and a war was won with what was appropriate and stepping rapidly through technology at the time. Someday the harrier will be dinosaur. We have just seen the new age starting with the "Dreamliner", though still current technology in many ways for passenger craft, there are huge strides made in this aircraft, much like the 747 opened a new era as well.

Small shops will still specialize with manual, and nothing beats a jig bore or jig grinder for its purpose with an artful hand running it. But, manufacturing will survive, and if it comes back (I think it can), it will through automation and CNC. It is NOT a love affair, it is the way things are turning. You will not ever see another major turning type shop opening by ordering 100 Cone-o-matic screw machines again when 10 Swiss machines will do and are more "changable" in product line instantly. Wish I could say better, Cones was 10 miles up the road and my wife's family all but grew up in that shop.

Here is another thought, what happens when CNC becomes obselete, Nanotech and things like 3-D printers coming hard and fast, it is just a matter of time before metal parts of all alloys and materials are "sprayed out" like a 3-D printer does with plastic now.

bborr01
02-02-2010, 09:40 PM
For the record.
I have spent easily in excess of 10,000 hours running manual mills and I would be the first to admit that I cannot turn out the quality of work that a cnc can. No matter how much time I would have to spend on the job.

Manual mills and lathes will still be around long after I leave this planet, and there is a time and a place for manual machines.

CNC's rock.

Brian

lazlo
02-02-2010, 10:21 PM
I have run everything from screw machines to turret lathes, horizintal mills to Bridgeports, Natco multi spindle drills, you name it but for a shaper. Been doing CNC since I had to punch in code on black paper tape on a Brown and Sharpe 40 tool machine center and a Hurco "answering machine tape" mill programmed through a TRS (Trash 80) 80 computer using ascii and goofball basic type commands.

I even started teaching grinding drills and lathe bits again - kind of have to so the CNC operator knows what is really going on, and what tool selection really means.

I think that sums it up right there -- a CNC operator is not a machinist.

It takes 20 years in the trade to become a master tool & die maker. How long does it take to train a CNC operator?

wierdscience
02-02-2010, 10:43 PM
Of course no one on this board admits to making scrap, but out in the real world I've heard the worst possible scenario when making a part is screwing up step #231, meaning you have to start all over again manually at step #1 and then manually do 230 steps to catch up to the mistake at which point you'll be even more tired and more likely to make the same mistake again. Oh well it builds character. With CNC you put in a breakpoint or truncate the g-code after step #230, re-run the program, and then manually figure out what is wrong with step #231, then finish it off.

I've seen the other side of that coin.Your assuming a machinist running the CNC.50% or better of the CNC shops I've seen working were owned by people who wern't machinists themselves and didn't see the need for a machinist as an operator.The Button monkey running the batch didn't catch the hair growing on all the parts caused by the chipped insert in a toolholder.As a result 150 pieces of scrap,all identical.That's just one example.

Many times management sees a double cost savings that doesn't exist.Saving scrap AND saving labor costs is what they see since "operators" are cheaper by the hour than machinists.It's fallacy,but it's also common.

toolmaker76
02-02-2010, 11:32 PM
Weirdscience, bingo! That is one of the things I have seen a lot lately. I started this thread not as manual vs. CNC, but the attitude that CNC is superior.

Case in point, actually happened recently, CNC lathes were tied up on some long running jobs, there was a job that needed to be done and well within the scope of a set up on a manual lathe. There was no programming time, or set up time for that matter with a 3 jaw chuck, just a couple of test cuts to get my dimension and feeds/ speeds, etc. but I was questioned by the owner for using a manual machine even though 1- the time was comparable and 2- the dimensions were all WELL within tolerance. This was done at a time when the CNC's were busy with other jobs, so the job was done as a bonus to the other work.

If you can drill a 1" hole to an XY dimension from the edge of a part, and the dimensions are exactly what the print shows, then it is right whether it is drilled on a mill, drill press, or machining center. If your print specifies a 3" diameter, and the finished part measures 3", then isn't it right whether you do it on a manual or CNC lathe? I realize all the merits of CNC and have programmed and use them myself (though not in my own shop). But there are people who think CNC is the ONLY way to go- usually those who have no machining background.

beanbag
02-03-2010, 12:04 AM
It takes 20 years in the trade to become a master tool & die maker.

How many of those 20 years are spent learning skills that have been superseded by modern technology?

lazlo
02-03-2010, 12:19 AM
How many of those 20 years are spent learning skills that have been superseded by modern technology?

So you're saying that machining skills have been superseded by modern technology? So you don't need as much skill, because of CNC? :)

John, this is much better than knurling and coax's :D

oldtiffie
02-03-2010, 12:26 AM
I think that sums it up right there -- a CNC operator is not a machinist.

It takes 20 years in the trade to become a master tool & die maker. How long does it take to train a CNC operator?

Lazlo.

A CNC operator IS a machinist - he operates a machine. Not all machinists are "masters" either as some are not much better than trained monkeys. Its quite possible to train just about anyone in short time for "operating" a machine on a repetition environment - press and turret lathe work are but two of many examples - always has been. There ARE some very good machinists and lot are bloody near useless and a lot in between. Some machinists have no formal training and have to just pick it as best they can -and some bad habits that are hard to get out of - as they go along. Some operate a limited range of machines on a limited range of jobs for years on end. Some are the equivalent of those who assemble pre-fabricated house frames.

There are a lot who have a wide range of skills. Some don't need years of training either.

A CNC operator who can code his machine is very competent. Most tools and machines soon make it pretty evident when they are "not happy" and many with any sort of mechanical aptitude will soon sort it out - or learn to.

If a CNC machine operator can use a CAD/CAM package and do the design as well - as many can - then we have a more vertical, integrated and efficient structure than the traditional way of doing things. And all those needed skills "pay more".

So far I am with Bob Warfield and co. 110%.

There are always going to be some non-CNC machines in some shops while there are shops that need them. But they will always be in the minority.

I have my Sieg X3 mill all ready to be CNC-ed as soon as I can see my way clear to have it done on a "turn-key" basis - new computer and all - with "manual" control if and as required - on all 4 axis. Its all paid for. The Sieg SX3 is here as the X3's manual replacement.
http://www.cnckits.com.au/product_mx3.php
http://www.cnckits.com.au/photos_mill.php
http://www.cnckits.com.au/videos_promica.php
http://www.cnckits.com.au/product_tv6.php

As soon as its all bedded in/down, the HF-45 mill is headed for the scrap-yard and the tip. The 8" "Vertex" rotary table and anything that is not suited to the SiegX's is going with it.

I am seriously considering getting a new "turn-key" CNC lathe as well and the old lathe and any stuff that won't suit the new lathe will be off to the scrappers as well.
http://www.cnckits.com.au/product_l280.php

I think that these kits and machines have all the best features of the traditional "all manual" and the new "all-CNC" machines. So its not an "all or bugger all" situation either.

I think that I've accumulated enough "on the job" nous to be able to make a fair fist of the judgment needed and the change.

I am 73 and I am buggered if I want to - or need to - spend countless hours over machines. I done my lot in that regard. Hot and cold shops, machines and tools are something I could do with a lot less of at my age and stage in life.

I like an intellectual shop/machine/tool-based challenge and CNC and CAD is it. I can do the computer work in the house and install, test and run it on the CNC-ed machines when I want to.

CNC is like CAD in that the work can be saved, up-dated, re-worked, saved and sent as any other computer file can be.

With me with CAD and CNC, its not a matter of finding reasons why I should make the change (I certainly can) but rather finding reasons why I should not (I certainly cannot).

I still have my grinders, welding and fabricating stuff, so I am not stuck for CNC vs non-CNC variety.

There is a lot of unwarranted "romance" about the "old masters" in their "old shops" doing wonderful stuff on their "old machines".

Of course it applied to some - but certainly not all - of them. It was all too often just a hard slog under $hit conditions under $hit bosses under $hit conditions on not much more than subsistence wages. Did I mention "lock-outs" and poor housing and poor health - and broken ill men? It certainly was not all like that but enough of it was.

I was very lucky in those respects as were most of the Tradesmen and Apprentices that I worked with - but in many cases their fathers and their fathers before them got it very "tough". And that is why they were so heavily unionised - they had to be - and so did I. I joined the Union as soon as I was 18 (minimum age) and have been a member ever since (it was suspended - not canceled - while I was in the Navy) and I still am (retired member) - 58 years ago and 58 years continuous membership - and very proud and glad of it.


It takes 20 years in the trade to become a master tool & die maker. How long does it take to train a CNC operator?
If that is true, there are some embarrassing questions to be asked about who-ever took that long to learn a job as well as who-ever employed him to take that long.

I've seen 18/19/20/21 year-old Apprentices who were very competent T&D makers and setters, Fitters, Tool-makers, Instrument-makers and machinists. They would have been excellent CNC and CAD operators too.

Its a truism that the only thing to fear is fear itself.

Same applies to just swinging over to or jumping into CNC.

The people - all ages - of yesterday could do it - as can the people of today and of tomorrow.

bborr01
02-03-2010, 12:53 AM
Oldtiffie,
Retired union member here too.
35 years membership and counting.
Never a regret.
Brian

bobw53
02-03-2010, 01:11 AM
To me, manual and CNC are the same damn thing, its just who's turning the handles, is it some carbon emitting coal burning power plant:rolleyes: or a bacon and green chile pizza(that one produces a lot of methane).

I leaned (not including college and high school) on some really crappy CNC machines and manuals. The CNC's sucked, so a lot of the work was done on manuals. Its all the same principals. The tricks that work on a CNC work on a manual, and the tricks that work on a CNC can be applied to the manuals.

A piece of metal doesn't know if its on a manual or a CNC, if its in a home shop or a pro shop, if its a one off or one piece in a million part run. Its all the same, just cuttin' metal.

As for the CNC snobbery of customers, I've never had one that gave a crap. Good parts, on time, Thats it. When I sub something out, I don't care if you make it on a 1902 shaper or a 1 million dollar 47 axis machine or a with a file and a hammer. Do I get good parts on time?

Mark Hockett
02-03-2010, 02:16 AM
The CAM program doesn't do the half of it for those that are thinking they do. Most are shocked at how much the machinist/programmer has to tell that CAM program to get it to do something smart instead of something stupid.


Bob,
I kind of hate to bring this up as it will make it seem too easy but my latest version of Mastercam X4 will program the part by its self. It is called Feature Based Machining (FBM). Mastercam will take a solid model, pick the tools from my tool library generate the tool paths to make the part with just a few clicks of the mouse. I can generate complex programs in minutes and usually have a prototype out the door in a couple of hours. Before the same part might have taken a couple of hours just to program. FBM utilizes High Speed Dynamic Milling cycles with tricordial cuts when necessary.

Here is a press release about it,

Mastercam’s Feature Based Machining


Tolland, CT – With its release of Mastercam X3, CNC Software, Inc., introduced Feature Based Machining (FBM). FBM eliminates the manual processes involved in identifying features for programming milling and drilling operations on solid parts. By analyzing the part for specific feature types (shapes, size, location of holes, etc), FBM can automatically create the individual toolpaths needed to machine the selected features and intelligently design an effective machining strategy.

Mastercam X3 includes two types of FBM toolpaths – FBM Mill and FBM Drill. Both toolpath types use information derived from the part’s features in combination with a stock definition to accomplish the following tasks:

- Detect all features for the selected FBM toolpath type, based on selection criteria the user defines. The user can then review all of the identified machining features, and selectively modify or remove features from the list before generating toolpaths.

- Select the appropriate tools, either from a preferred tools list or from specified libraries.

- Create and assign boundaries needed to drive or constrain tools.

- Automatically generate all of the toolpaths necessary to machine the features.



FBM Mill

FBM Mill analyzes a solid part, detects all machining features in a specified plane, and automatically generates all of the 2D milling toolpaths necessary to completely machine the selected features. FBM Mill machines closed, open, nested, and through pockets. For complex nested pockets, Mastercam defines a separate zone for each depth, and also creates the boundaries required to machine it. FBM Mill employs the following types of 2D toolpaths:
- Facing toolpaths when stock in the Z-axis is above the top of the part

- Roughing and restmill toolpaths for each zone

- Separate finish toolpaths for walls and floors in each zone

- Outside contours when the stock extends beyond the part in the X and Y axes



FBM Drill

FBM Drill performs the following basic functions:

- Detect holes in a solid based on specified criteria

- Review the detected features list and edit or delete features

- Preview toolpath operations and make additional changes before they are generated

- Automatically generate a complete series of drill operations for the selected features

wierdscience
02-03-2010, 02:25 AM
Weirdscience, bingo! That is one of the things I have seen a lot lately. I started this thread not as manual vs. CNC, but the attitude that CNC is superior.

Case in point, actually happened recently, CNC lathes were tied up on some long running jobs, there was a job that needed to be done and well within the scope of a set up on a manual lathe. There was no programming time, or set up time for that matter with a 3 jaw chuck, just a couple of test cuts to get my dimension and feeds/ speeds, etc. but I was questioned by the owner for using a manual machine even though 1- the time was comparable and 2- the dimensions were all WELL within tolerance. This was done at a time when the CNC's were busy with other jobs, so the job was done as a bonus to the other work.

If you can drill a 1" hole to an XY dimension from the edge of a part, and the dimensions are exactly what the print shows, then it is right whether it is drilled on a mill, drill press, or machining center. If your print specifies a 3" diameter, and the finished part measures 3", then isn't it right whether you do it on a manual or CNC lathe? I realize all the merits of CNC and have programmed and use them myself (though not in my own shop). But there are people who think CNC is the ONLY way to go- usually those who have no machining background.

I maintain that there are some jobs that should not even be considered for CNC.
Local plant here that made agriculture parts,disc spacers,mower parts etc.Everything in the plant was manual,punch presses,turret lathes everywhere.The cast disc spacers were being machined on a couple old Gisholt turret lathes,two plunge cuts on the turret with a form tool on each part tolerances were +/-1/32".Production rate was 50 pieces per hour with a trained operator.Another turret lathe part was a bearing spindle,three shoulders and one thread +/-.0015",two box tools and one geometric on the turret and two OD tools and one cutoff on the slide.Maybe 20 piece per hour,still nothing special.

They did it manual that way for 20 years and made a good profit,then the company was sold off to another firm.New manager was an idiot,first thing he did was trash the spacer operation and replaced it with a Fadal VMC.Next the spindle machines went,replaced that with a Mazak lathe.

The Fadal was doing trash work and buried in ductile iron swarf which did no good for the machine,that crap gets everywhere.The Mazak was waaaay biggger and more $$$$ that they needed or could afford even though they were able to turnout good work on it.

Those changes along with others made a profitable company into a good auction in 16 months.If they stuck with the 20 year old depreciated turret lathes they would most likely still be in business.

I don't have a single CNC machine at work,yet I routinely compete against CNC shops on small parts.On a simple part a Hardinge 2nd op turret lathe can compete with a CNC assuming a good setup,the cycle times just aren't that great a difference between the two.That little machine was paid for a long time ago,if it doesn't run every waking minute I'm not losing money.I have another larger turret about to go back online since the CNC only shops are folding againt.

Mark Hockett
02-03-2010, 02:57 AM
.On a simple part a Hardinge 2nd op turret lathe can compete with a CNC assuming a good setup,the cycle times just aren't that great a difference between the two.That little machine was paid for a long time ago,if it doesn't run every waking minute I'm not losing money.

I would have to argue with that statement. With my CNC lathe I can run other machines while it is working, that would be hard to do on a turret lathe which in my mind is a big difference between the two. The CNC turning center I am getting will run unattended with a bar feeder and parts catcher. That means I can take a nap while its running if I want too. I do lots of plastic and aluminum parts so tool wear is not an issue. I would imagine at the end of the day after running a turret lathe a person would be fairly tired. My Haas TL paid for itself in less than two years and with the two new customers I just picked up the new lathe should pay for itself in a year.

Rustybolt
02-03-2010, 07:18 AM
I think that sums it up right there -- a CNC operator is not a machinist.

It takes 20 years in the trade to become a master tool & die maker. How long does it take to train a CNC operator?


Quite right, but somebody in the shop needs to know the how and why. You can read up on speeds and feeds all you want , but the real lesson is the tool in the work. There is a world of difference between 4140A and 4140HT.

Michael Moore
02-04-2010, 02:03 AM
I don't make any claim to being any kind of machinist other than a "home scrap machinist." But my CNC mill lets me make parts that I'd never have a hope of making on the manual mill it replaced.

Actually, my CNC mill lets me make parts I wouldn't even have attempted to make on the manual mill. I'd have just said "there's not a chance in hell of making that so I won't even try."

I'm very surprised at the people who try to conflate a CNC operator with a machinist. That seems like two different skill sets to me. Even I, as a "not a machinist" probably exceed the skill set of a CNC operator.

I have to 2D/3D CAD the part (after designing it mentally). I have to then figure out how to run the CAD through the CAM software (which involves picking tools and feeds/speeds/step-overs/DOCs etc). Then I have to actually set it up on the mill and run it.

That seems a bit more complicated than just pressing the green button.

I would like to have been able to keep my B'port clone manual mill just for those times when I want to drill a hole or two without waiting for the CNC mill to boot up. But a decent drill press with an XY table would probably suffice for those types of operations. I really loathe getting out the electric or pneumatic hand drill and wrestling with a piece of metal on the garage floor only to make a somewhat circular hole in somewhat the right location. :)

Some people have superb manual dexterity and fine motor skills. The rest of us don't.

When it comes to a user interface I'm somewhat more adept with a computer than I am with handwheels. Why should I make substandard parts with a manual machine when I can make higher quality parts with features that I'd never attempt on a manual machine with my computer and a CNC machine?

Frankly, I'd be glad to jump ship from CNC to 3D printer if it would give the same quality/accuracy/material qualities. But then I make stuff because I like to see the end product, not because I want to demonstrate my (non-existant) mastery of fine hand/eye coordination.

CNC lets me mill for a couple of hours or more with a 1/16" EM without breaking one. The manual mill wasn't that helpful.

cheers,
Michael

Kibby
02-04-2010, 03:49 AM
Within a half generation, virtually no one will know how to operate a manual machine.

Sad. Does anyone even know how to design and draw blueprints the old-school way? Probably never even taught anymore. When I was in highschool, I took mechanical drawing every year for four years. When that long-overdue big solar flare hits, every computer on the planet will be cooked. All I will need to do is fire up a generator, or some wind-generated power, or hydro-power, or solar-power, and I'm busy making swarf.

A guy standing on the ridge with an M4 and a full clip is only king until the ammo runs out. At that point, the last man standing will be the guy with a bow or spear.

Evan
02-04-2010, 04:56 AM
Manual machines aren't going away any time soon. They do jobs that CNC can't do easily or in some cases at all.

I was standing around watching the guys in the local job shop one day when the wheeled in a pulley that needed to be trued and regrooved. It was a little over 33 inches in diameter and about 6 inches wide on the face so they put it on the big lathe. The object was to remove as little material as possible to maintain the same ratio as much as possible. First job was to skim the circumference until it was trued up with no high or low spots.

Right there CNC can't handle it since it requires human visual inspection on each pass to see how much more to remove. The next part of the job was to deepen the belt grooves back to spec since the tops had been cut down.

All of this relied entirely on the ability of the machinist to observe and measure the part as work progressed with those observations and measurements determining the next operation. Along the way adjustments were required in the middle of a cut to deal with the pulley ringing like a bell.

This is ordinary and common work in any industrial setting where large machines need maintenance. The demand for this sort of machining and the equipment to do it isn't going to disappear and neither are the people required to do it.

lazlo
02-04-2010, 10:36 AM
Sad. Does anyone even know how to design and draw blueprints the old-school way?

I was the last class of young engineers taught manual (pencil and paper) drafting at Virginia Tech, in 1984. I believe the same is true at most other engineering universities.

BobWarfield
02-04-2010, 11:14 AM
The thread is definitely on a par with coax and knurling, LOL!

Michael: Absolutely right that it is a mistake to conflate a CNC "operator" with a CNC "machinist". Much closer are the one man band CNC shops. Those guys are very much machinists and can take just as long to learn all the tricks as Lazlo's master machinists.

Bobw53: We agree--the only difference is who is turning the handle. There is also a difference in the kinds of skills that may be needed (other than handle turning), but there is also a large overlap.

Mark: Feature recognition is an interesting area of function. Can the CAM look at a drawing and sprout a finished program that's great? I will wait to hear your experience with it. My own research into the area and experience with CAM is not optimistic. FeatureCAM is called that because they pioneered the area. Yet, you can see from threads on their board that very few people use it for much because it is wrong too often. Hole recongition seems to be about it.

And Lazlo, so worried about the loss of knowledge. A half generation from now, yada, yada. Well quit building those microprocessors that rob our children of the ability to need to know long division. Quit using calculators. Quit using computers altogether. In fact, why not go fully "Amish"? Leave the manual machines aside and spend your time filing and scraping away. Such technology built the Antikythera Mechanism and much else, so it is not to be discarded as impossible.

OTOH, it's been silly to argue the Luddite perspective since those days of throwing wooden shoes into the machinery and it continues to be silly.

Since this is a hobby board, you may very much enjoy the notion of manual machinery and be applauded for doing so. Jay Leno gets a real kick out of driving steam powered and other "obsolete" automobiles. Jay is a good guy so you're in good company.

At the level of a hobby, it's all about doing what makes you happy. At the level of a business, it's all about doing what pays the bills. Still plenty of manual machine opportunity there too, but it is dwindling and becoming more and more specialized. Take care not to be the one to turn the lights out.

Cheers,

BW

small.planes
02-04-2010, 03:46 PM
Does anyone even know how to design and draw blueprints the old-school way?

I was taught drafting by my father when I was about 6 or so. I still do a lot of ideas with pencil or Rotring Isograph pens. When I was at secondary school in the early 90s we still had to design the projects we made on paper with 1st and 3rd angle projections and 'traditional' drafting skills. I doubt its taught anymore though, computers have become so ubiquitous that even my 4 year old daughter uses them with aplomb
Nowadays I use solidedge at work, and its so much faster to design a cock up :rolleyes:

Dave