What kind electornics in CNC Mill

I have built prusa before and now i would like to do CNC mill.

But what electronics i need? Is there some lowcost sangunololu style boards for cnc stuff?
Can i choose what ever steppermotors that have enought torque. And what about stepper drivers?
Which software i recomended?

This is low cost project so its also possible that i do electronics board by myself.

Edit: Also this should be able to mill aluminium.

Edited 1 time(s). Last edit at 01/30/2013 10:30AM by eniq1on.

... why not use the electronics and drivers of your prusa?

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Viktor
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VDX Wrote:
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> ... why not use the electronics and drivers of
> your prusa?

Nema 17 are too small maybe so ill need bigger motors -> i need new stepper drivers ->
Would this setup work Arduino uno + GRBL + some bigger motors and some random drivers for motors?

... the common used polous are good for up to 2 Amps if applying coolers ... I'm sometimes driving my CNC-mill with a Gen3 or Arduino Mega - it's equipped with 3Volts/2Amps-NEMA-23 motors and the drivers are 6Amps@70Volts types ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Any work on your CNC mill?

I started a CNC router, seen here: [www.youtube.com]
For electronics I'm using an arduino, but I'm experimenting with firmwares still.
I've tried GRBL on an UNO and Repetier, Marlin, Teacup on a mega (like a ramps 1.4, but the sheild is not needed because I used larger drivers and I don't need the mosfets). So far, I've had the most success with Repetier.

interesting, would you be able to elaborate what you found so favorable abt the repetier?

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Here is rundown of my experience, so far, with each firmware:

GRBL: works really well except for bumps in acceleration algorithm which I'm afraid may cause lost steps (this was supposed to be fixed in the latest beta, but it seems to have a simalar but different problem). Supports very fast step rate, up to 30,000 Hz. GRBL would be optimal as it's made for a CNC but it seems the 3d printer firmwares have gone through much more development and have a lot more useful options that GRBL doesn't have yet. e.g. endstop searching with offset (for use with metal plate for Z homing).

Teacup: also works well but my top speed is very limited because it's step rate tops out at just over 12,000 Hz (the newest teacup was supposed to tripple this but I experienced no increase). Thats plenty for the typical 3d printer with 1/16 micro stepping drivers. But for machining aluminum I want very smooth movement so I have drivers that are capable of 1/125 stepping. 1/125 is not necassary so I'm using 1/50 micro stepping. Here's some quick math so you see the speeds I'm looking at.
125 steps per mm with a 12,000 Hz stepping limits me to 96 mm/s. For a lot of cutting that's alright, but if I'm doing a big carving that'll take all day. I'd like to get 400 mm/s, at least for travel moves.

Marlin: I didn't do must testing with because I immeadietly had some very bumpy accelerations. I think it has something to do with the pulse widths that marlin sends. I've read they're very short, like 1 micro second which is the minimum my drivers will accept. I suppose Marlin would also have a similar stepping limit as Teacup but I haven't tested top speeds with it.

Repetier: Support up to 16,000 Hz stepping rate out of the box. However, it has a double and quadruple step function that allows it opperate at an effective 40,000 Hz. There are a couple issues that I have yet to worked out, though. For some reason the lowest acceration I can set in it is 350 mm/s2. Anything lower and there is no deceleration. It accelerates fine but once the distance has been reached it abruptly stops. The other issue is that G0 and G1 are combined. This would be alright if I could set a default speed, but it doesn't seem to be an option and I'm not sure how to modify the firmware to increase this speed. Without this my travel moves are very slow.

Thanks for the detailed experience report, Mior.

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endstop searching with offset (for use with metal plate for Z homing).

Interesting you mention this typical non-feature as example. Non-feature, because a G28 without offset, followed by a G92 gives you exactly what you need. That's why Teacup doesn't have and likely never gets this.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

I am using repetier for both firmware and host, azteeg x3. i would like to try Aspire, but I could really benifit from some guidance regarding required post processor.

Maybe it is a bit too late but in my experience most (if not all) postprocessors of Aspire will create lines of code without G0/1 at the beggining. They are valid g-code but at least Marlin won't like it (I guess the same holds for Repetier but I have not tested).

One simple solution is to add a couple of sed rules to add G1 to any line starting with Y,X or Z.