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Author Topic: Recomendation for parallel or USB controller + motor brands (CNC plasma cutter)  (Read 3263 times)

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Hi everyone. I work for a small company and we would like to get set up with a CNC plasma cutter, but they cost a lot and we decided to build our own.
BUT I have a lot of questions considering I have never thought of building a CNC machine before:

1.  Which is the better option for the breakout board connection? USB or parallel port? We have computers with both for the software.

2. Any recommendations on breakout/controller and motor brands? Which ones work good for you? Cheap is good (price-wise). only need x, y, and z axis.

3. And I'm not sure of what size stepper motors we need, but we need to be able to move a big homemade steel gantry over a 4' x 8' sheet of steel. Can you use small motors and gear them down, like for example a 3 to 1 reduction? Is there a chart or system to figure out how much torque needed? Would like to just use small inexpensive motors and gear them down to give them enough torque to not slip or miss a pulse. The machine doesnt have to move fast from what I see.

4. Does Mach 3/4 have the ability to turn on a plasma cutter torch with, for example,  a relay output on a controller board? I have the ability to make a relay driver from transistors from logic level.
Button option in the software? In the past I've seen people use a router as a cutter and they just turn it on manually before starting the cut. But that probably wouldnt work too good for a plasma cutter.

Thanks for any info, it's really appreciated!

Offline BR549

  •  6,965 6,965
Thousands of people are running a plasma table with Mach3 software. It has all the features you need to do it with. AS far as Motion to motor ratio you want to be at 1" of motion per Revolution of the motor. Steeper motors have a very limited TORQUE range and yo have to sty inside the envelope for things to work well.

Gantry ? The way is go is as LIGHT as possible. There are ZERO cutting forces involved so Ganty overkilll is a bad thing. SLOW ??not so slow light guage cutting can run into 300+IPM feedrates.  At that speed you need to maintain a very LIGHT ganrty so that you can run with HIGH aceeleration rates to keep from rounding corners  excessively .AND not loose steps   Acelleration is KING in plamsa cutting for most forms (artsy stuff).

I would suggest you talk to someone like TOM over at CandCNC he can get you straight on what you need.  IF you have never built a CNC
 "PLASMA "table you need some GOOD advice on motion hardware. Tom will steer you straight IF you are one to actually listen.

(;-) TP

(;-) TP