[bcmoore]

Greetings,

I'm trying to make a 3D wire bending machine, similar to the DIWire prototype which is explained in more detail in this instrucables page:
DIWire Bender

Basically it uses 3 stepper motors, one to feed the wire, one to rotate a solenoid rod which does the actual bending, and one to rotate the plane of rotation (for 3D geometries). So, 3 stepper motors hooked up to drivers which in turn are hooked up to a psu and an arduino.

a few questions for now:
-Would it be possible to power the drivers with a benchtop style PSU? I'm thinking it could come in handy to have a PSU with different voltage and current options for future use. Is there any serious technical reason NOT to use a benchtop/desktop PSU other than maybe things like size constraints etc.?

-Because I'm a student and my budget is somewhat limited I've been looking for cheaper stepper motor options. Found some considerably cheaper Chinese options, but I was wondering if anyone has had any particularly bad experiences with chinese made motors?

-One thing I want to add to this set up is a an extra motor/mechanism for cutting off the wire once the shape is bent. Wondering if anyone has developed an automated bolt cutting system or something along those lines? I figured a really straight forward approach would be to integrate a rigged bolt cutter in the set up and use a geared stepper motor...but that just seems like a very inelegant move...

I'm quite a noob at this, so any input would be greatly appreciated.

Thanks a lot guys.

Cheers,

ben

[Al_The_Man]

It would not necessarily be my first choice and a lot depends on the design of the PSU, you don't need a regulated supply for steppers or servo's, it is very simple to but a 3 component linear supply together, Transformer/bridge rectifier/capacitor.
Al.

[bcmoore]

Thank you for your input.
I don't know if I would be able to put a PSU together...my knowledge regarding PSU's is quite limited.
I'm inclined to get a benchtop powersupply with various different current and voltage options because then I could use it for other things...so I think I'll go ahead with that.

[wizard]

Thank you for your input.
I don't know if I would be able to put a PSU together...my knowledge regarding PSU's is quite limited.
I'm inclined to get a benchtop powersupply with various different current and voltage options because then I could use it for other things...so I think I'll go ahead with that.

Really you don't want to do that! There are all sorts of bench supplies out there with their own regulating behaviors, over voltage protecting and the like. In a servo or stepper system such a supply would be more trouble than it is worth. That being said a bench power supply is handy.

Al was right on target you don't need much for a servo or stepper power supply. A transformer, rectifier and some capacitors will do the trick. Frankly if you can't handle this you really shouldn't be looking to build a CNC machine of any sort. If you can't come to grips with a simple DC supply I really don't see you having success with the rest of the machine components.

You may have other good reasons to avoid doing a DIY supply, if that is the case you have other options:
1. Buy a purpose made DC supply. These are usually far cheaper than a bench/lab supply anyways.
2. Buy stepper drives that run from line voltage. However if you can't manage a DC supply I really can't see you being safe wiring up a bunch of AC components.
3. Retask an old PC power supply. These are workable for 12 VDC systems. Lots of online info on how to retask these supplies.
4. Buy an assembled drive system that takes care of the AC & DC issues for you and gives you three axis of drives.
5. Get a good book on electronics and learn before you get burned. Ideally you go into these sorts of things with enough knowledge to keep you out of trouble, the hospital or morgue. You may notice that I'm concerned about your safety, that is because of your statements about the DC supply. Sometimes the sailing is far smoother if you know before hand what the weather is. What does that mean, a little prep (education) can smooth things out for you and up your confidence.