Starting my foam cutter....

[nikolatesla20]

Here's my control board and the two steppers I plan on using. I'm trying to build a foam cutter for use with Lost foam metal casting. But I'm not going to be casting very large parts so the machine will be designed with a "coping saw" type of arrangement for the hotwire. I want to try casting some gears out of AL so hence the need for CNC to cut them out for me. Not really something you can cut out of foam by hand! Lost foam casting works awesomely simple for the DIY !

Here's some pics. Controller board is two UCN5804B chips driver the steppers in unipolar two phase mode (two phase gives more torque). I have no idea how much torque the motors are, I'd have to test it. They are 400 steps/ rev and 16.5 ohms. Hence I have a 22 ohm 2 watt resistor in series with them since I'm pushing 12V (the motors are only rated for 400 milliamps so I need resistors).

That's a big chunk of AL for a heatsink on the IC's. They are mounted in sockets for ease of replacement if they decide to blow out.

Pretty ugly wiring eh? lol.

-niko

[CNCadmin]

Keep the pics coming!

[lepton]

I'm interested in your controller design.
where did you find the information on that design?

thanks

[nikolatesla20]

Hi lepton,

At the place I work we build scientific instruments with stepper controllers and such in them. I hence knew that you could use a UCN5804B chip - since it's an all-in-one stepper motor driver. It just takes pulses in and then moves the stepper the right way. I used schematics of our own equipment to figure out how to wire the motors the right way, since they didn't have the traditional color coding of most motors (most of the colors were usual, but some different).

The UCN5804B has a pulse pin, an enable pin, and a direction pin. So you can just pick a parallel port pin to connect to each of these and then configure the software to know which pin is for what.

-niko

[TinkerDJ]

You might not want to base any new board ideas on the ucn5804b chips as they are obsolete and may be hard to find. Some of the ideas in the open source forums are probly a better idea. But you already have working boards so no problems. I blew up my 5804 board by not having the chips properly heat sinked. But it worked very well. I'm casting with the lost foam idea aswell, i have the bow saw kind of idea for my hot wire foam cutter. I was thinking of making a cnc cutter but i was going to use 3 steppers so that i can cut out airplane wings and fusalages. Keep us posted on your build.

[hotroad]

hi. can you sand to my he borad digram??
I am trying to build one.