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Thread: Reasons to convert a mill to CNC

  1. #1
    Join Date
    Mar 2001
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    Nottingham, England
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    Default Reasons to convert a mill to CNC

    Reasons to convert a mill to CNC


    Model Engineering today is just as popular as it was years ago but other factors have changed.
    Many of the older Model Engineers came from engineering backgrounds or similar. Many had come through the ranks of time served apprenticeships or learnt skills in the forces.
    For the people not so fortunate there were a whole area of training establishments like colleges and night schools that threw open their doors and welcomed these people. There were also far more clubs that there are today. Around me there is only one club but years ago there were seven offering help and advice to budding Model Engineers.

    The main crux of the matter is though, there was more time available. We didn't have all the current trappings we have today that need maintaining or require attention. Most people worked local and traffic was non existent so leisure time was greater taken overall.

    It was not out the ordinary for the average Model Engineer to disappear into his shed or workshop most nights a week to carry on his hobby. Today given the pace of life it's a rare person who can get two nights to themselves what with modern pressures.

    Whereas our intrepid hero would disappear for 4 or 5 consecutive nights to machine a tricky widget, usually right first time as he had the time and peace to do this, it's next to impossible today. Todays Model engineer is lucky to get two nights a week after late night shopping, going out for a meal and dare I mention Ikea? OK we won't mention Ikea.......

    So that two nights now becomes a mad dash to get our scale model widget sorted. Because our modern ME now has no formal training or apprenticeship, limited club membership and attendance will use up one of these 'special' nights and the last college doing training in the arts of metal bashing and regurgitating is now teaching Chinese students the art of grabbing all the jobs.
    The result is that after two nights our widget is now undersize because of the rush.

    Now we have to wait a whole week to start all over again. Next week we take a little more care and start again, two nights later we are half done and we wait again for our next time in the workshop.
    This time we get a move on because two weeks is long enough to do what LBSC / Martin Evens / Duplex / E T Westbury [delete as required] would have done in a night.
    R
    esult we scrap that bugger as well.

    Enter the house all sad and upset kick the cat and Gert say's something only women can say, something like "I don't know what you get up to in that shed of yours" Fortunately for the cat it's out of range.
    Why can't her indoors be attuned to the situation like the cat is?

    So you are in the shower at night [this goes to show how times have changed, LBSC / Martin Evens / Duplex / E T Westbury {delete as required} would have had a bath, after removing the coal first] and you think to yourself "I wish I could get it right first time"

    This is where technology comes to your aid, you can, it's called CNC, short for Computer Numerical Control where a computer actually runs a machine by following a code entered into it.
    Basically you have a number of building blocks from various suppliers that when assembled make a complete CNC machine.

    For starters we have a computer, that is loaded with a program to run the machine. This program is called the Controller.

    From the PC via a printer cable the signals go to another building block called a Breakout Board. This is an electronic relay board that assists in the connection process but more importantly it acts as a buffer between higher machine voltages and the PC.

    Moving on from the breakout board the signals then go to a driver box or board. You need one driver per motor.

    Feeding into the driver as well as the input signals from the Breakout Board you have a power supply that drives the motors through the drivers.

    Then from the drivers you have the motors, you need one motor per axis so in the case of a mill you have three, X, Y, and Z

    Once these components are all assembled and connected to your host machine you are ready to go. Depending on the controller software used, determines the next step.

    Some can only work with pre written code, some can read in CAD drawing in a DXF format, some can work in conversational mode which is where you select a picture of the type of job you are doing and fill the blanks in and the controller writes the code.

    Now this is where we take over from LBSC / Martin Evens / Duplex / E T Westbury [delete as required]

    We spend one night sat in the warm house doing our drawing and sorting the code out. [NOTE : This is an Extra night to one's hobby as if we are INSIDE we can't be accused of being OUTSIDE, so now we have three nights to play]

    We do our job, sort what tools we want to use and watch the simulation on the screen, most times we even get a run time. When we are happy then we have a program that will run on the machine so the next free night we run this and get a perfect part off first time, well the first time after the learning curve has leveled off :-)

    So now after a bit of experience we can churn out in two nights what it took the masters a week to do. I bet LBSC / Martin Evens / Duplex / E T Westbury [delete as required] are churning in their graves.

    Brownie point note:-
    These CNC machines are brilliant at doing engraving and a few gee-gaws and shiney magpie baits for her indoors will work wonders for the free time.
    Note do not under any circumstances engrave RIP or In Memorial plaques for Mother in Law whilst still alive, for some reason this doesn't go down a bundle.

    John Stevenson

    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  2. #2
    Join Date
    Feb 2006
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    Harwich,Essex,UK
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    Red face

    OK got the message,
    My first reason to CNC a mill was to do sign engraving whilst having the ability to do other things. So far I have spent a small fortune and still do not have a functioning CNC mill. The problem is in the very steep learning curve into just what is needed to accomplish the conversion without spending mega bucks - although in hind sight it would probably have been cheaper to have bought a ready finished mill or at least have started with a larger mill (Sieg X1 at present)
    I must say that the enlarged knowledge base on this site is a god send but due to my limited tool resources (but growing fast) has somewhat limited my progress in that every thing I want to do nearly always requires an extra bit of kit to be acquired (I really enjoy buying tools but SWHMBO does not appreciate this)
    Peter

  3. #3
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    Western New York U.$.A
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    Default

    I'd give my eyeteeth if I could get into that but think it's a bit out of my league. I could think of a million uses for CNC. My patience is thin where making multiple passes across the same cut are needed to accomplish the desire result.

    But even if I could pull off the mechanical aspects of CNC I would have a very hard time kicking out the kind of money needed for adequate software. It is well worth the cost in industrial setting but I'm working in the barn for fun! CNC is likely one of the only things I will not have been able to do before I cash out

  4. #4
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    Nov 2001
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    Toledo, Ohio
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    Default

    It's called progress. The future generations will have a very different set of skills and tools available than the preceeding ones.

    The technology has progressed at such a rate that CNC is now economically available to the HSM, and the programming methods have become simplified enough to make them easily learned. Add to that the ability to translate a CAD drawing directly to a finished part and it becomes even more appealing.

    Many of us old dinosaurs will continue with the tools and skillsets we have, but more and more will begin the shift to the new methods.
    Jim H.

  5. #5
    Join Date
    May 2001
    Location
    Colorado
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    Default

    You must have a crystal ball!! Right on the money. That is exactly why I just purchased a benchtop CNC mill. Time in the house to do the drawings and then when that "shop night" does happen, I can get more than just a partial part done.

    Jim

  6. #6
    Join Date
    Aug 2005
    Location
    Grayling, MI
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    Default

    Quote Originally Posted by Your Old Dog
    I'd give my eyeteeth if I could get into that but think it's a bit out of my league. I could think of a million uses for CNC. My patience is thin where making multiple passes across the same cut are needed to accomplish the desire result.

    But even if I could pull off the mechanical aspects of CNC I would have a very hard time kicking out the kind of money needed for adequate software. It is well worth the cost in industrial setting but I'm working in the barn for fun! CNC is likely one of the only things I will not have been able to do before I cash out
    YOD,

    Actually, software can be the cheapest part of the whole setup. I'm in the process of designing and building a CNC machine to assist me in making bamboo fly rods. It will be cutting the tapered bamboo strips. So far, the computer and software are the cheapest parts of the whole thing. I picked up an older P4 machine, with about 512 MB of memory, loaded Ubuntu Linux on it, and EMC2 CNC software (both open source and available on the web). So far, I have about $50 invested in the computer/controller software. Check out http://www.linuxcnc.org/ for the EMC2 software. There's also links on the page to get you to the supported version of Ubuntu that EMC2 is compiled to work under.

    Mark

  7. #7
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    Jul 2004
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    Tarkio,Mo.
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    Default

    It took one night just too wright that post. LOL
    Gary Davison

  8. #8
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    Mar 2001
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    Nottingham, England
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    Quote Originally Posted by gld
    It took one night just too wright that post. LOL
    But if I hadn't used a computer / word processor it would have took 3


    .
    [Edit] the post was written a while ago as an article with humorous references but it's very close to home.


    .
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  9. #9
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    In the fog of San Francisco
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    As is normally the case, there are tradeoffs. I spent several days tweaking the drawing for a stamp I made for a local guy (the letters all had to be slightly moved apart to allow the EM to get between them - standard fonts/kerning don't seem designed for CNC use) and several more days fiddling with the CAM side of stuff (but both the CAD and CAM were definitely learning experieces so spending extra time was expected).

    So that part was certainly a lot more time consuming than dashing off a quick sketch and getting to the machining.

    On the other hand, after the no doubt very unoptimized code had the mill chewing away for 4 hours, I had a useable part and ZERO broken 1/16" end mills. I can't imagine running an end mill that small manually without breaking one every 4-5 minutes while I was fresh, and probably every 4-5 seconds after I got tired.

    I think a lot of it depends on what your project is. Some projects can probably be whipped out on a manual machine in less than the total time needed to do CNC. But if your project is very complicated, has lots of contouring/radii, needs very accurately spaced features, or has a looooong run time CNC can have some big benefits.

    I see CNC as something that allows me to have something other than straight lines on a part (without reaching for the dreadnought file). A CNC mill will cut any curve (or combination of curves) you want as easily as it will a straight line. That was not my experience with a manual mill.

    cheers,
    Michael

  10. #10
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    Jun 2006
    Location
    Austin, Texas
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    Default

    Quote Originally Posted by wendtmk
    Actually, software can be the cheapest part of the whole setup.

    I picked up an older P4 machine, with about 512 MB of memory, loaded Ubuntu Linux on it, and EMC2 CNC software (both open source and available on the web).
    That's the controller software -- is there such a thing as affordable CAM software?

    I've got the CAD side covered, and Mach3/EMC2 covers the controller, but the CAM software seems pretty expensive.
    With my casual shopping, SheetCAM seems the cheapest at 85? Any other options in the frugal/cheap end of the
    price range?

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