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Evan
05-27-2004, 02:51 PM
I have a friend that is a Jewler. He owns a New Hermes 810 CNC engraver. This is a first generation machine from the 80's and the computer control is proprietary and primitive and failing. I am considering retrofitting it for him with modern computer control using something like Geckos and appropriate software. Has anyone here ever worked on or with a similar machine? Any ideas?

jfsmith
05-27-2004, 02:56 PM
Evan,
I worked with one of these machines, htey do what they do well. The one I worked on seemed to like 286 processors and wouldn't work witrh a 386 or a 486. Plus it was very DOS based somewhat crude software. Now I wish I had bought one of them when they came out of service for my shop.

Have fun,

Jerry

ibewgypsie
05-27-2004, 03:14 PM
Something interesting,

ALL windows fonts are engravable. All of them with a free program.

Geckos are fine if you don't run them at MAX power and expect them to live. I guess that goes for everything else in the world including all machinery.

They keep telling me Mariss is coming out with a frequency generator that runs outside the computer and allows much greater speeds. Pretty cool if it works.

What do you need to make it happen? I have lots of junk laying around.

You did say? steppers or servos? I really like the Rutex servo drives, Pride will not allow me to purchase a gecko servo drive.

LOts of software on the market, some really good 3d jewerly type software. The bobcad I have will wrap text onto a 3d plane.
I am seeing new motorcycle parts related to the new 3d modeling advances that have came about.
I am still working on toward my 3d scanner. If I had big money laying around I'd purchase one.

David

DR
05-27-2004, 03:20 PM
I've seen a few of the smallish engraving machines. They really zip around.

From what I've seen of the hobby conversion type stuff you'd be hard pressed to match the speed of the proprietary controllers. But, if you're only going to fool around with this on a hobbby or limited production basis speed may not be such an issue.

Evan
05-27-2004, 03:59 PM
This wouldn't be a hobby project. Budget for the conversion would be a couple of thousand. It has steppers, not very large, small H bridge drivers will work fine. What I would probably do is gut the electronics housing and put in a micro ATX motherboard and power supplies to run the computer and stepper controllers. Any of the high end engraving software would be his responsibility to buy although I would set it up for him. He has two of these machines and one is not being used because of electronics issues so I wouldn't be under a lot of pressure and could take my time. I also would make some money on the project (or free engraving for a long time).

Does anyone have any specifics on the motors on this machine and can anyone recommend good windows based engraving software?

DR
05-27-2004, 06:11 PM
Okay, commercial use.....then you do need the speed. I wonder what the fastest speed the current crop of home-brew CNC's can move at.

On the Yahoo group I see conversions where they're talking in the 20 to 40ipm range. At that speed you'd be ready to slit your wrists waiting for a job to finish.

I'd say the commercial engraving machines I know of are rapiding in the 200+ipm range. Whether any of the stepper systems can run at that speed I don't know. The problem is the CPU/software can't generate the pulses fast enough. Maybe using coarser pitch screws is the way to accomplish the speed with a little loss in precision. For engraving precision wouldn't seem to be a major factor anyway.

ibewgypsie
05-27-2004, 06:20 PM
Dr..

With a modern computer speed is no problem.

My nema 42 motored mill will run faster with the Larken drives and 2.4 intel machine then it did with the boss setup. the hobby is catching up with the old technology. After installing Mach2 I was hitting G00 speeds of 260 ipm reliably.
If I want to go faster I need to go to servo drive with encoder feedback. My machine is just a stepper type. The more modern welder robots I teched on would hit speeds of 2,000 ipm with servo drive. Much less inertia to overcome thou.
With a smaller motor and the gecko microstepping I see no reason why a smaller machine with less inertia should not hit 2 or 3 times that speed easily.

Look up Desk Engrave.. it is a free program. I highly recomend the new Mach2 for simplicity and ease of use.

David

John Stevenson
05-27-2004, 06:21 PM
DR,

At present using Mach2, with a good choice of motor and ballscrew 250 in/min is easily achieved.

Mach2 is currently running at 45,000 pulses per second.
Later this year when the Gecko G2002 comes out on general release, beta's are already running , that will go up to one million pulses per second.
This is because the timing will be handled by the 2002 and not windows.

That will be in excess of any but the most expensive commercial controllers out there.

Not bad for a sub $500 setup ??

We live in interesting times.

John S.

Evan
05-27-2004, 06:24 PM
The 810 is a very small machine. It is a 2D engraver and the working area is around 8" x 10" max. It currently isn't fast at all so it wouldn't be hard to improve on it. Years ago I built a flat bed plotter with steppers that I ran at around 2500 steps per second using a 1 MHZ 6502 CPU programmed in assembler. That worked out to about 15 inches per second. I'm sure the 810 is no faster.

ibewgypsie
05-27-2004, 08:57 PM
One thing to note, with my mill: the table weighs in excess of 200lbs, the rotary indexer that was bolted to the table weighs about 200lbs..

Not to change the topic, but has anyone saw a conversion utility that swaps linear to rotary axis positioning files? I can move one axis at a time by file but not interpolated.

I'd sure like to play with Mach2 on the Robots locally. I'd sure like to build a simple robot for the other plan I have here too..

David

John Stevenson
05-28-2004, 04:44 AM
David,
Bobcad can do this.
You draw your part in the flat as though it was unrolled from a cylinder and then you tell bobcad to roll one axis round a cylinder with a given diameter.
Something like a snail cam is machned as a Z plunge, and X and A rotary movements.

Dolphin does it a bloody sight easier but that's another story !!

Here's a shot of a 6 speed racing bike gearchange cam done that way on Dolphin.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/rotary%20cam1.jpg

John S.

ibewgypsie
05-28-2004, 08:03 AM
John..

Maybe I meant to say global coordinates instead of polar.

Spherical coordinates just like space. ALL different directions.

I can and may play some with the bobcad when I get a lil more time here. I had more time when I was working at tva I think..

Possibly the teach program I wrote using the usb joystick is what I really want. It'll locate each point and shoot to it.. problem is that no interpolation exists. if anything is in the way it is so dumb it'll crash..

It was kinda funny going over to a sanyo robot that had crashed.. the old man was prying on it.. he'd pull it, it'd go right back to the same spot and crash again.. he was trying to force it to where he wanted it to go.. I hit the estop. put it in manual, went around the welding jig and reset home. (it runs home wide open to home like a spoiled horse)

There have been hundreds of cases where a welding robot has speared someone. them things move fast and don't care if you are in the way.

David

Evan
05-28-2004, 11:00 AM
David,

Thanks for the tip on desk engrave. It wouldn't be suitable for the Hermes but it looks like something I can use. I'm also thinking about CNCing the Unimat. I need more time/money/servants/grounds-keeper....

Mike W
05-28-2004, 02:13 PM
A grounds-keeper would be nice. http://bbs.homeshopmachinist.net//biggrin.gif

ibewgypsie
05-28-2004, 02:52 PM
I know exactly what you mean. I have spent more time with the lawnmower than my bridgeport.

I got plenty of small sized steppers (250 oz) here.. somewhere... (2 hours to find maybe) I got some synchronous motors that can be retapped too and I know where they are.. them are pretty big thou, about 6-8 inches in diameter.

I have been working on a gantry machine now for about six months. I have had the gearbox reduced servo motors that long.

Building the 5 foot x 6 foot press I might just set the two together. Take some playing to get the structure running that true thou.

The unimat cnc sounds pretty neat. Give you a chance to do real accurrate machining over and over. What I have found is the downfall on my cnc is tool set up.. It has to be exact. I need to build a set up tool and kwik switch holder. (possibly the linear readout I have)

I made two mistakes this week, first involved cutting my finger pretty bad, second was the setup on the table under the morse 1 1/4 drill I had just used Monday. The Retract value was wrong and now I need another bit.

Check Check double check is what I do at work.. I seldom ever make a mistake I don't catch. Perhaps I need to bring that ideal home with me.
The turbocnc site says it all, making scrap rapidly is what cnc is all about.

David

John Stevenson
05-28-2004, 06:52 PM
David,
Go to http://www.cncedit.com and download the demo.
This is a very cheap simulation progarm that follows the toolpath you have written.
The demo isn't crippled but it's cheap enough to buy.
Load your code into this program, hit F11 and you wil get a simulation window come up.
You may have to set preferances under settings.
Then when you hit S it will single step theu the code. If you get a no no swopping back to the code window will show you what line the no no occured.

When I used to use Blobcad this little program saved my rear end a few times with it's spurious Z moves.

John S.