cnc machine

hi guys i want to build a simple cnc machine and i would to controll it by my arduino uno ,stepper motor and the l293 so i need i help for build it and i have no ideas about the softawar and how i can transmit it to the arduino

Start by using the search feature on this site to see what has been discussed before about CNC.

I suggest you start by getting the 'Motor Knob' example working as linked from here: http://www.arduino.cc/en/Reference/Stepper.

Then edit the code to get the stepper motor to do what you want for CNC.

One acronym of use: GRBL

This project of mine might help http://www.thebox.myzen.co.uk/Hardware/CNC_Conversion.html

Mike & Mike - those are certainly impressive Arduino projects but you still need to use a PC to control it. So I wonder; why not just run LinuxCNC or Mach3 on the PC and use a parallel port to drive the stepper drivers? What is the advantage of using the Arduino?

Russell.

Linux is crap and I don't have a PC I have a Mac.

The Arduino with GRBL accepts Gcode and controls the motors. So no problems with timing, as the Arduino handles that.

And that was the original question...

If you can find a laptop with a parallel port, the timing will be screwed up.

Many hobby level CNC machines use GRBL with an Arduino and a suitable board with something like the Pololu A4988 chopper stepper drivers.

This one takes replaceable Pololu or compatible A4988 chopper drivers, up to four so you can double up steppers on one axis in the style used for the Shapeoko 2: http://blog.protoneer.co.nz/arduino-cnc-shield/ |500x374

Or there is the GRBLShield, but if you blow any chips, you have to replace the whole board unless you are good at SMD replacement. This is NOT the same as a motor shield: http://www.adafruit.com/products/1750?gclid=CjwKEAjwh6SsBRCYrKHF7J3NjicSJACUxAh7EB6gXHI7S9_0O7EHrRdaWIW47NDyQCTpqwBmVKqNNhoC2qrw_wcB |500x332

Grumpy_Mike: Linux is crap and I don't have a PC I have a Mac.

I'm not going to go into the Linux vs Windows vs OS X argument here. We all have our prejudices.

Russell.

LinuxCNC is an obvious approach, tis true.

polymorph: If you can find a laptop with a parallel port, the timing will be screwed up.

Agreed. I picked up a used PC for next to nothing to drive my cnc mill conversion and installed a version of Linux with a realtime kernel to get good timing.

I imagine an Arduino solution is good for a 3D printer so that it can be left running offline but I want a good human interface so that I have full control while cutting expensive metal.

Russell.

russellz: I'm not going to go into the Linux vs Windows vs OS X argument here. We all have our prejudices.

These are not so much prejudices but more of experience. The Mac is the best of a bad bunch.

The parallel port's days are certainly numbered and USB-based controllers (like an Arduino / RAMPS) will certainly take over, but you can worry about that later. The parallel port is much easier to work with for a first time CNC builder. There won't be any advantage to using anything else until you start learning the ins and outs of these machines and their mechanics and start understanding what it means to optimize their performance. That'll probably be your 2nd or 3rd generation machine though.

Grumpy_Mike: These are not so much prejudices but more of experience. The Mac is the best of a bad bunch.

He had it right. Your experience's helped develop your prejudices and my experience's have led to mine.

It doesn't help to confuse opinion's with fact's

Where is my Amiga?

http://www.polyphoto.com

Chagrin:
The parallel port’s days are certainly numbered and USB-based controllers (like an Arduino / RAMPS) will certainly take over, but you can worry about that later.

That’s true, although parallel port cards should be available for a long time. But, yes, I can see the advantage of using an Arduino to communicate with the PC (that’s Personal Computer Mike not specific hardware) via USB serial port. One problem though is that the USB protocol isn’t realtime.

The parallel port is much easier to work with for a first time CNC builder. There won’t be any advantage to using anything else until you start learning the ins and outs of these machines and their mechanics and start understanding what it means to optimize their performance. That’ll probably be your 2nd or 3rd generation machine though.

Hopefully the problems of using USB with LinuxCNC will be resolved. Mach 4 is designed for USB use but there are no suitable plugins yet and besides that program costs.

Incidentally, the speed limitation on my cnc machine is the cutting speed for steel not limited by the computer although perhaps that would change if I wanted to do laser engraving or some such.

Russell.

One problem though is that the USB protocol isn't realtime.

That is why I chose to have the computer send Gcode to the Arduino and then the Arduino turns that into motor pulses.

although perhaps that would change if I wanted to do laser engraving or some such.

Not likely as laser cutters / engravers involve moving something ( laser or mirror ) and communications over USB is way faster than anything that has to physically move.

Not a surprise, but I agree with Grumpy_Mike. I have a hard time imagining a Laser cutter moving faster than USB 2 could transfer data, even with latency and delay. If you've cut your curves up into -that- many line segments, better rethink your settings.

Sorry, I must have been unclear. I meant that my cnc mill, using the parallel port, has adequate speed on the steppers for cutting steel but that if I wanted to do laser engraving it might not cope with the speed although the USB and Arduino would.

My mill build here is three years old now and If I was starting again I might do it differently.

Russell.

I misunderstood, I thought you were saying the reverse.

Nice conversion.