Need Help!- Choosing the right part

[prabb]

Hello

I have planned to convert my Wolfcraft coordinate board ( http://tinyurl.com/cgo7qn and http://tinyurl.com/b3wqlf ) to a steppermotor controlled cnc-board. The main purpose is to engrave coppercoated circuit boards, so no massive forces are needed (copper is 35 µm thick). The coordinate board is very light to move with the cranks. Of course, an extra efficiency is not a disadvantage, if the budget won't rise too much.

The problem is, that I don't actually know anything about stepper controllers. I could buy a ready industrial solutions, but they can cost near 1000 euros. That is a little too much.

Can somebody help me to choose the controller and maybe a suitable stepper motors? I have experience and devices to build even tiny smd-circuit boards, so DIY-kits are no problem. I have looked that ebay has a wide range of parts, but buying without knowing can revenge itself.

Thank you in advance!

[CarveOne]

You would need to remove the X and Y axis hand cranks and figure out a way to mount the stepper motors so that the stepper motor shafts are connected to the crank handle shafts through a flexible coupling. You don't seem to need anything as large as a NEMA 23 frame stepper motor. Many people use stepper motors from old printers for things like this. You will need to have a third stepper motor (Z axis) to raise and lower the router between cuts.

HobbyCNC sells a low cost three axis stepper motor driver DIY kit for $64usd. http://www.hobbycnc.com/products/hobbycnc-ez-driver-board-kit/

You will need to know the specifications of the motors and determine if this kit will drive them. If your stepper motors have a shaft on both ends you may be able to install the cranks on the stepper motors and not lose manual control of the x-y table when the power is turned off.

CarveOne

[prabb]

Yes, I do have some stepper motors from demolished printers. But most of them are very small (from basic inkjet printers). I don't actually know how the force is relying on the size of the motor.

However these two Sanyo Denki motor are the biggest I've found in my collection: (the bigger motor weigh ~350 grams and the smaller 200)
http://tinyurl.com/at6a32
http://tinyurl.com/ck79rh
http://tinyurl.com/ddhbgm
http://tinyurl.com/b7faqn

I could possible find bigger motors from demolished copying machines in nearby recycling place. But which features are most important, the number of wires, degrees, resistance etc.

The mounting of the motors is not a problem, as I'm planning to mill suitable toothed wheel for belt drive. I'm lucky that my boss gave me admission to use companys cnc-machiningcentres on freetime.

[CarveOne]

If you mount this onto a stiff aluminum plate then you can mount the motors on the plate since you want to belt drive the shafts. It makes things easier and it is all movable as a unit.

Old dot matrix printers and line probably had more powerful motors in them. I don't know if they can be driven with modern driver boards though.

CarveOne

[CarveOne]

Just or comparison, my NEMA23 425 oz/in 3Nm motors weigh 1360.8 grams (48 ounces). This motor is much larger than you need to run the X/Y table you have.

I don't see a Nm rating on those labels so we can't determine their torque by comparison to my motor. See if you can find the specifications online and get an idea how much torque they have. If they are a little weak you can make up for it with gear reduction.

CarveOne