[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]

~~~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]

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]

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

[DarkWolf]

Graham,

Many thanks for the input as always. I'm not counting them out as an option and you do make a good point about it..

Think I have the basic idea on motors and rails, plus there is tons of info in the forums on the rest of the rig and how to do it..

I'm still at a loss on the controller though.. At this point I am leaning to a 3 axis instead of 2 axis and an actuator.. But where to find a good inexpensive controller is leaving me a bit lost..

I'd be willing to work off of plans as well on the controller, as long as the parts are cheap and easy enough to come by (IE: order them from one or two places)..

[Graham S]

Doing a google search would be a good start for drive schematics.

I built mine from these plans:

http://hans-w.com/cnc.htm

They are very similar to the Camtronics 3 axis bipolar chopper drive.

Also see:

http://www.cs.uiowa.edu/~jones/step/

[DarkWolf]

Do all controllers work with all the software, are they standardized as to the controls?

I think I've seen some that say they're limited to their own software.. Guessing I should stay away from that..

Wouldn't mind having a 3-axis with pause, 3 homes, and 6 inputs to keep the axis's from going too far..

[c_nut]

There is a piece of 'freeware' that I found that converts text input to gcode. If I remember right it has some ,need to, connected to it. I have it downloaded somewhere,home work or in between. Will search it out and get the url.
I would suggest Turbocnc. Runs in DOS--say old computer--no$ here. A $10 registration if I remember right. Three axis and more, feeds step direction or step controls directly thru parallel port. Do a google on turbocnc and see. I have two 12 volt steppers running on my desk and the motors are driven by four tip102 transistors fed step coil signals from the parallel port. A simple constant current source produces a good torque without expense.
I use a piece of software called Dualstep to test the motors and the power supply. I will try to get the info togther and post it for you. Will take a few days as I am loaded with that stuff that makes my wife happy. Over time.

Gotta go!
From the swamps off mile post 223 Interstate 10.

[Graham S]

The registration of TurboCNC is now $60 however the downloadable version is fully working without registering. I am sure that given the circumstances the author would not mind it if you didn't register, especially if you ask.

I use TurboCNC myself, it works very well and is fully configurable to work with any parallel port based controller. You can have home and limit switches.

[DarkWolf]

Thanks c_nut and Graham for the input as always. Sounds like a very good program indeed.

I use TurboCNC myself, it works very well and is fully configurable to work with any parallel port based controller. You can have home and limit switches.

So it works with most controllers? Very good.. I was looking at the one you posted ( http://hans-w.com/cnc.htm ) and it looks like a great setup. Especially with the ability to be expanded into a 4th axis.

Question though about it. I see only one limit input.. Can it be wired so that XYZ all have high-low limit switches (6 total) onto that one input?

Where do you think the best place would be to order the parts? I'm not sure where to get the chips.. Checked on partsexpress.com but I didn't find any.. It's been a LONG time since I was into electronics.. The most I recall is the 555 timer..

[Graham S]

Yes just about any parallel port based controller.

Hans cnc:

There is a home switch for each input, these can be configured to act as limit switches too I think. Then for the other limit of each axis you put the switches in parallel and wire to the single limit input or indeed you could wire all switches in parallel into that single input. I suspect however that given the repetative nature of the task home switches would be handy.

Components:

Whatever you decide to build (and the one I listed is probably not the most simple/cheap option) digikey is probably the place to get the components, they have a huge range.

Graham

[jeffs555]

Another good place for electronic components is www.mouser.com Their selection is nearly as good as Digikey, and in some cases they have things Digikey doesn't. I buy from both, but for orders under $25 Digikey adds a $5 handling fee and Mouser doesn't.