2 axis linear machine control ?

[vostryc]

I need some software direction, for building a drilling machine in my woodshop, using stepper motors.
I would like the drill machine to work as follows:

* I secure a piece of wood to an single-axis, 8' long linear table/slide.
* Push start button ...table moves to the first pre-determined hole position.
( using an encoder counter )
* Drill spindle will be lowered to bore a hole, a pre-determined depth.
* Drill spindle retracts to it's home position.
* Linear table/slide moves to the next hole position ...repeat ... to the end
of the wooden piece... then returns back to it's home position.
* Insert new piece of wood ...

I know this can be done using a PLC, or a $10,000 controller.

But, could I use one of the simple 2 1/2D CNC program's for this application ?
Trying to program this using Ladder Logic is an effort ... I would rather fill-in
a few forms on the computer monitor ... getting lazy in my old age ...

Anyone have expirence with this type of project?

Tks,
Chuck

[Graham S]

You just need a couple of stepper motor drivers, a laptop or any PC running dos and a copy of turboCNC (free to try).

http://www.dakeng.com/turbo.html (download it and read the readme to see how simple it all is)

Say your lumps of wood are quite heavy you might want to use a decent sized stepper motor so a www.geckodrive.com would suit well, you also need a powersupply and a parallel port cable. You then just write a very simple program in gcode to do what you suggest. You don't need an encoder as the motors will move the axis by a given amount with each step. The spindle can likewise be moved down to the required depth and back up again.

You would probably add homeswitches to find the zero of both axis, this could be done at the start of each cycle or just at the start of the day.

If you have not seen g-code before

G00 X100.0 F100

Would move the x-axis which might be your wood moving axis by 100" at a speed of 100"/min.

There is a similar command for a drill cycle and you just retract the spindle by the same amount it plunged. Then another G00 command to move to the next hole, then another drill cycle etc. Finally move back to the start, you can add a user interupt command so the user can load the next plank and then press go.

So now I have saved you nearly $10,000 can I have the change

Graham

[vostryc]

Tks Graham,

I am printing the extensive manual now !

The G code looks straight forward enought ...

Thanks for your quick assistance
cv