Help for a newbie

[jfroage]

Hello the group. I want to control up to 6 stepper motors with a computer. I am going to build a CNC machine to run a wood router. I can handle the mechanics but just don't know where to start with pic chips, interfaces, micro controllers, stepper motors, and so forth. I am okay with the math and the electronics also if it doesn't get to deep. I just don't know where to start looking for the information I need to get started. I don't want to purchase a lot of stuff that I don't need. Some of you pros point me in the right direction. Thanks.

 

[(*steve*)]

The method I would use is to have a microcontroller controlling the stepper motors, and the computer sending instructions to the microcontroller.

I have a colleague who has a similar arrangement, albeit his setup is a simple X-Y table and the instructions come from a series of buttons, but the principle is the same.

The advantage of this is that the computer can send high level commands like "move X stepper 1000 steps" and the microcontroller can do this for you. In my colleague's case, this involves stepping at an increasing rate until a certain speed is reached, then slowing down prior to reaching the destination position.

Splitting the hardware implementation details from the software helps make the system more reliable and the software simpler.

For routing, you probably need several types of "move", a slew -- which gets from one place to the other as fast as possible -- and a "cut" which moves steadily, possibly at a settable speed.

At the hardware level (the uC), you need to decide if you need to lock the stepper in place at the end of each move, or de-power the stepper completely.