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Wednesday, October 24, 2012

Low Cost CNC Part VII - It LIVES!!!

So for the last, nearly two years, I've been working on building a low-cost, homemade, 3-axis CNC milling machine.  Today for the first time, I can say that I've done just that, having finally actually cut something.  As far as I know, it's the first milling machine build largely from 3D printed parts.

You can see the entire process, from the beginning, in the previous six posts:  Parts I, II, III, IV, V and VI.


The mill is shown below, along with the 3-axis CNC controller that I've posted about before. 


The spindle is a low-cost Dremel tool, currently attached with a Shapelock bracket.  It will no doubt get replaced with something less awful in the future (I am referring to both the Dremel and bracket, of course).


I have a Rotozip spiral-saw bit in the Dremel tool, to stand in for a proper milling bit.  It's a bit flexible, but more than up to tearing through MDF.


The whole setup is shown above and gives a good sense of scale.  My 3-Axis controller board is in the bottom right, controlled by my laptop.  The CNC itself has around a 6x6x4" working volume, although this is arbitrarily expandable in the X-direction.  The controller board runs GRBL, for which I have written a simple GUI for adjusting settings and jogging the machine. I plan to release the code for this when it stabilizes a bit, since GRBL needs a decent GUI.  I intend to add some basic features, like simple pocket/contour milling.  But for the time being, it's simply a software pendant.


So with everything set up, it was time to start cutting.  I attached my 3D printed iPhone mount to the XY table, started the Dremel, pressed record and began jogging the machine.  The result is pure awesomeness, for me anyway.



I had either the cutting depth or the feedrate too high for the spindle speed, since the bit began 'climbing', rounding the edges of the square when the feedrate was high.


But guess what? I don't care! 'Cause the CNC that I started nearly two years ago, which has been my preferred hobby while simultaneously being intensely frustrating has finally, finally, cut something. Praise Jebus!

Obviously there's refinement to be had.  For one thing, the ~10 mm long square sides should actually be one inch.  And I should make sure that the axes are actually square (I'd be shocked if they are).  Also I want to package the electronics in the base extrusion, provide a proper power-supply, perhaps some heat-sinks on the stepper drivers and maybe attach a real spindle.  And then there's ballscrews/belts.

But that's for later.  For the time being, my CNC actually cut something.

To my knowledge, this is also the first milling machine built substantially with 3D printed parts.  I hope in the not-to-distant future to get the feedrates up to the point of being able to 3D print with the mill itself. I also intend to build a tapping attachment to tap the holes used in the aluminum plates, which is -really- time-consuming and error-prone. This would make the machine as much of a RepRap as most 3D printers are, but considerably more solid.  But that's for later.

6 comments:

Loial Otter said...

It's always awesome to see a project like this take life. It helps reinforce that following plans isn't the only way to build stuff. Keep up the awesome work!

How's deflection so far? Bring it into the hackspace some time; I'd love to see it in person.

Thanks,
Loial

James Gregson said...

Thanks Loial!

With no proper way of mounting workpieces, a weak plastic spindle mount and the long flexible spiral-saw bit, its hard to tell what is actually doing the flexing. However I do see the bits 'climbing' with respect to the spindle direction, so there's definitely some deflection. When I get some proper table clamping and use a decent end-mill I hope to get a better idea of where the problems are.

I will bring it by the space, probably to leave there if room can be found. My carpeted, small apartment is not well suited to milling. Otherwise I'll have to disassemble it, which would be sad.

James

Unknown said...

Hello friend, you are providing the software that runs the grbl? I have grbl my arduino gcode but universal sender does not work properly ... please help me ...

Unknown said...

Hello friend, you are providing the software that runs the grbl? I have grbl my arduino gcode but universal sender does not work properly ... please help me ...

Irfan Ali said...

Thanks for taking the time to discuss this, I feel strongly about it and love learning more on this topic. עיבוד שבבי

Mark said...

It will no doubt get replaced with something less awful in the future (I am referring to both the Dremel and bracket, of course).cnc milling machine