[DrewSmith007]

I'm in a class where we have to build a project, and I want to build a small rotary engraver that can do 10 digit phone numbers on the back of a rabies tag for my dad's vet clinic.

I don't want it to have a pc attached to it, I would like to do a microcontroller. I have a little experience with basic stamps, but thats about it.

I think I can handle the hardware part of the engraver, but I'm not sure how to do the software. It seems like it would be easy to use gcode for the digits, but I'm not sure how to connect all that to stepper controllers.

Does anyone know of a good place to learn about stepper controllers?

What are everyone's thoughts on this?

[DrewSmith007]

Changed my mind, that would have been a little over my head. I'd like to use a PC.

I probly only need 2 inches in x and y, and only 1 in z.

I'm thinking x & y table, z with the gantry.

[High Seas]

Take a shuffle over to MAJOSOFT's site (you can google that). He's done quite a bit in that DIY size and has some online software that will generate Gcode from text (save a bit of $$ there too.) A trial version of MACH2 should get you started . A system that size could mount right on top of the pc case and keep the footprint real small - not as small as a system you originally thought - but easier integration. Moving small bits- means smaller stepper motors and less expensive controllers. You could try and do it all with floppy drive motors - a fellow in New Hampshire has some good info on his site - I'll look and repost as I have time...
Good Luck, Jim

[NEATman]

Another suggestion to keep the cost down and make the build easier is to get an old tower computer, with enough room inside to mount the stepper drives. If the motors are small enough, you can probbably tap right off the 12 volts on the computer's power supply. You may even be able to mount the stage right to the computer case - just keep the chips out of the computer!

Also, a dremel tool should be adequate for this application, and they are easy to mount to a Z axis. Plus, I have found that small center drills fit directly into the collets of the dremel, and work well for engraving. I have a small 4" x 4" x 2" travel engraver with a dremel tool, and it does fairly well at engraving aluminum.

If you use Mach3, try the trial version. It has a wizard right in it that does one line of text. I have used Mach3 and center drills in my bridgeport to engrave several names of my co-workers in black anodized aluminum. I think that the results are quite good. The text on the nameplates in the pics is 1" high, and about .008" deep with a #2 HSS center drill.

Good luck with your project-
NEATman

[DrewSmith007]

Thanks for the hints guys, i'll definatly check them out. I happen to have a few computer's around, collecting dust. My problem is I plan to give it to my dad once I get the grade, and I don't think he'd use it unless it was something like:

Step 1: Type in phone number
Step 2: Click Engrave

It couldn't be that hard to write a program that can just do numbers in a (XXX) XXX-XXXX format, could it? Maybe store the Gcode for each number, 0-9, and have an ofset for each digit, using block letters?

In either case, I can build the hardware part and get the grade, and can always convert it when I get the software figured out.

As far as power considerations go, I pulled the steppers mostly out of printers, so they should be able to run with a small power supply, say 12 volts? Some steppers came from a photocopier, but they're pretty small.

Thanks for all the help.

[High Seas]

If you still have the printers lying around - you can consider using the rails and the printhead section for your axis linear ways. Also the gearing etc. I would have mentioned it earlier - but there is a bit of time involved in getting them all sorted and torn down. Didn't know how soon the project was due! The wizard in MACH3 sounds like the shortcut software wise.
I bet your dad could figure out the steps once you showed him! There are quite a few clever "senior" members on the 'Zone
Jim

[DrewSmith007]

I've saved all the rails and gears from the stuff I've torn down. I figured out a way to make a little money cutting out silver letters, so I decided to use the rails I have to make a 20 x 15 x 5 or so Mill. That small, I think i'll still go with a fixed gantry, except z-axis. If I want to machine aluminum, what kind of steppers do you all recommend? Also, what's a good spindle?

I had my lab for my manufacturing processes class, and the equipment is amazing. They've got a haas CNC mill, a CNC lathe, 5 manual mills, 2 big and 4 small manual lathes, 3 plastic injection molding machines, a laser scanner with a .005 tolerance, Aluminum and brass foundry, anodizing equipment, a 5' x 10' CNC router/plasma table, and a whole lot of other stuff I'm sure I'm leaving out.

The lab is private industry funded at a public university, so my fee's don't go towards purchasing equipment I actually get to use, but I can't say I mind too much.

And, the instructor is looking for some part time student help setting up all the new equipment, I think i'll double major to stay here longer...

[DrewSmith007]

Well that was a pretty long gap between posts, but I've been working on this pretty much ever since, although mostly in my head.

I've made quite a bit of progress on the software and stepper control side of things, but almost none on the mechanical parts.

I'm graduating in May, and right now I'm in my senior design class. I've decided to make this project my proposal, and if it's accepted, it's going to be made.

I've got the code figured out where it accepts letter inputs for the clients name (in text messaging style), then accepts digits for their phone number, then accepts letters again for the pets name. It then cuts each letter and number using subroutines for each letter. I got around the problems I was having by making each character start at the bottom left and finish at the bottom right. It is slightly slower than if it could move directly from one letter to another, but the code is MUCH simpler. Anyway it works now, and here's a video.

[ame="http://www.youtube.com/watch?v=3q7OaHH9rQo"]YouTube - Engraver Control Movie[/ame]

It uses a cubloc cb405 plc, a 4x4 keypad, LCD module, two steppers with drives, and a modified pc power supply to run the motors.

Anyway, I just thought I'd let everyone know how this is progressing. It should come along well as soon as we start the actual build.

Any questions or comments are welcome.

Drew

[LaserImage]

That's pretty awesome Drew! The only suggestion I would have is to have the program ask to redo the tag just in case something didn't engrave right. It would be annoying to have to re-enter all of the info.

How much do you have into the parts? I'm curious because I would really like to play with something in that scale myself.

Gary

[DrewSmith007]

I don't have any money in it right now, it's all on loan from a professor. It would be a few hundred dollars though, if I had to guess.

If you're wanting to get started with microcontrollers, try the radioshack kit "what's a microcontroller?" It's got alot of coding examples and exercises, plus it teaches you quite a bit about simple electronic circuits for less than $100. Check out parallax.com for the kit (they sell it too) as well as stepper motor equipment and other cool add on modules.

A book on BASIC programming would be useful too, as both cubloc and parallax chips use modified versions of BASIC. If you understand if-then statements, for-next loops and do-loops, you probably know enough to get started with your own programs.

Let us know how it goes, and if you have any questions about it I'll be glad to help.

Drew

[DrewSmith007]

Well my project proposal was accepted, so we're going to go ahead and start work on developing this engraver. I've recently learned I have access to a touchscreen LCD so I'll probably go that route instead of a qwerty keyboard or the sms text message method. I don't know what I'm going to do when I get out of school, I won't have access to all this cool stuff...

There's three other guys on my team, and they all seem talented and eager to learn. We should have a nice product by the end of the semester, hopefully sooner. I'll try to keep posting progress, but I'll also be really busy...

[Roger Hamlett]

As a lateral thought, why not forget electronics completely.
Unless this is part of what you actually 'want' to do, much simpler to build a pantograph engraver.
Not as good if you want to do fifty off the same 'tag', but for a single tag, faster than any simple CNC system, and a lot more flexible...
Purely mechanical.

Best Wishes

[DrewSmith007]

We've got the mechanical system designed. We went with a plasma cut plate steel frame with tabs that interlock to assemble before welding. We're going to machine several fine adjustement blocks for the guide rails and motor mounts. I'll post some screenshots and pics as soon as I can, I don't have a way to open the solidworks files at home.

Question:

I pulled some nema 17 motors from a photocopier and plan on using them for this project. here are their specs.

x & y 2 identical motors

shinano kenshi stp-42d208
1.8 deg/step 2.6v 1.2a

z

shinano kensi stp-42d204
1.8 deg/step 3.15v 0.7a

what do you guys recommend for drive chips? I sent an email to hobbycnc, but nothing yet. Also, can I run these at a higher voltage, say 18 or 24 volts? 12 would probably be enough, but I tested their holding torque at 5v and it wasn't very much.