Questions - Micro CNC router?

[DarkWolf]

Hi Folks,

Very new to all of this and have been browsing for quite some time. I have a few questions that I'm hoping you all can shed some light on.

First, let me explain the reason why I've found myself here and why I'm asking for advice. At current I do ALOT of work with a local Basset Hound rescue here in Kentucky. -- I can hear you asking what that has to do with anything CNC. Well, if any of you have ever gone out to buy dog tags, you'll see they cost at least $5 each or so. Now, I can get the blank tags way, way cheaper. But I'd need a good, clean, easy way to engrave both sides of the tag with various info.. Since we're a rescue, money is very very tight. In fact, anything I do on this will be out of my pocket, which is almost as tight..

So.. Here it goes. What I'm thinking of doing is a very small two axis bed with a powered engraving tip that lowers via actuator to a set depth. The area that would need engraved would be at the most 2"x2" and the material would be standard thin die cut aluminum dog tags.

Is it possible?

I have several floppy drives from computers laying around that are either dead (access wise) or I just don't need. Since the unit would be so small I don't feel there would be a problem at all powering the two axis bed with the stepper motors inside. From what I recall, they're 6 wire steppers BTW, but I have to check before I even think of moving forward.

Software wise, I do not think I'd need anything in the CAD/CAM market area. I'm very tempted just to code my own and toss together a dead of Linux box to power and run it. But if there may be something out there that's either dirt cheap or open source, that'd be great and save me time when I do manage to get this up and running, if it's even feasible.

Come to think of it, I don't know much about CNC work or building my own machine, so I'll no doubt be full of questions.. I do understand sending commands to a controller via computer though.. My current "fun" project is building a set of animatronic eyes that I'll have interfaced with my main work comp.. Having spare servos on hand and a few Mini SSC's is useful.. Gotta do something with them..

So what say you.. Is it doable.. Will it be dirt cheap and be able to scribe legible letters on a tag... Think it'll be cheap? Am I wasting my time???

Thanks for any input..

Scott--

[CNCadmin]

I would like to donate a power supply to you're venture, I have one that would be perfect for a stepper driver set-up.

(A dog lover)

[DarkWolf]

Thanks very much for the offer.. For right now though ideas and feedback would be great, just to make sure that I'm going to be able to move forward with this..

If I can get a full game plan on the table and figure out how everything will work and indeed get started I'd be honored to accept.. For right now, lets just plan..

[JFettig]

have you ever seen those manual engraver things? in jr high I used one, basicly it has letters and a little thing to follow the letters, you manually move it, and when you follow the letters on the template(wich you pick out individual letters) it engraves them into a peice.

I woudl suggest you looking into something like that, mainly because youll have to program each tag and it would probably easier to just set it up like that?


Jon

[Chagrin]

I'd look somewhere other than at the steppers in a floppy drive - assumedly quite weak and my experience with them leads me to believe they have a fairly huge degree turn per step. Most surplus sites on the internet should have more practical NEMA 17 steppers that would be much easier to work with for very low moolah.

[DarkWolf]

I'd thought of that, but I think it would be easier to do it this way. Each tag wouldn't differ too much, so working on a "template" basis in program would be easy. Plus this way a rough logo for the rescue could be placed onto one side. Plus it'd look better than a punch set...

[DarkWolf]

Originally Posted by Chagrin ~~~Most surplus sites on the internet should have more practical NEMA 17 steppers that would be much easier to work with for very low moolah.

NEMA 17 then? Sounds like something to look into.. Thank you for the tip..

[JFettig]

take a look at allelectronics.com they have a variety of small steppers.

Jon

[DarkWolf]

Originally Posted by JFettig take a look at allelectronics.com

Wow... Those are cheap prices there. Looks to be about $12 for 2 fairly good motors, though not much details.. What about controllers though?

Hey, cool... Peltier devices.. Always wanted to play with them..

[Graham S]

The quickest and cheapest way to build it will probably be to get a few little THK rails off ebay. Short ones that are often too small for bigger applications are always on very cheaply. Then use threaded rod for the leadscrews and delrin for the lead nuts. Use normal bearings as thrust bearings. Use flexible PVC hose to link motor to leadscrew. Buy a super cheap rotary tool for the spindle. Motors off ebay too. The driver may cost a little more. You can use a PC power supply (available free for almost anywhere) as you don't need huge speed over small areas. Gor for 1mm pitch threaded rod and you have super high resolution.

Here is an example of some tiny slides, you don't have to use these as there are many ways to do it but on such a small scale they would work really well and are VERY good bearings:

http://cgi.ebay.co.uk/ws/eBayISAPI.d...845460919&rd=1

Graham

[DarkWolf]

Originally Posted by Graham S The quickest and cheapest way to build it will probably be to get a few little THK rails off ebay.

I saw those today while looking around ebay for parts.. Not sure if the price is right though.. May be better off with a small shaft and some nylon to make bushings out of. At $25 per set, that'd put me at $50 for just the rails, where the nylon and rod may be $5 or so?

Precision isn't a big issue on this one, but I might keep those in mind for later on. No doubt after I get a taste of this I'm going to want to do more..

[Graham S]

It was just an example. As the rails ARE the machine essentially then $50 would not seem so bad (only need 10 tags for it to pay for itself) and these things are rated for 10's of 1000's of Km of use so they will last longer than the machine I would bet.

I was thinking ease rather than precision you could knock up the machine in an afternoon at it would work like a charm.

If you are good at machining then use your nylon (or Delrin) and get building.

Graham