Thursday 20 November 2014

Building A Piccolo Micro 3 Axis Robot Part 1

The Piccolo is an open source laser cut tiny 3 axis CNC machine designed by DIATOM Studio. It uses and an Arduino based microcontroller and 3 servo motors to move a 3 axis. The basic design is for a pen plotter but I have seen many examples of other applications like a vinyl cutter or even a miniature lathe.

There isn't a kit available yet, but the designs and software is all open source and available to download from github as well as all libraries to get it up and running the software is supported on Windows, Linux and Mac. There is a PCB available from Piccolo but not necessarily required as the design can be run from and Arduino with a few components on a breadboard.

First of all I  had to laser cut the design there was plenty of electric blue Perspex offcuts lying around  I had to collect some other parts together to build it, There is a full Bill Of Materials in the Github repo with link to recommended Digikey parts. 

The instructions on Piccolo website are very clear and take you through the construction process in an easy follow step by step guide.

Most of the parts are invertible but the rack and pinions are have a specific orientation the above photo is where you can see my mistake.  It also shows which direction to set the servo into and where to fit it. If don't set the servo up in this way the axis will not be able to move through its full range.

When I assembled this axis I couldn't move it and that is the point I realised my rack was on back to front, OPPPS :). Something I do like in this design is some of the layers are held with a friction fit around the screw, this account for different levels of width tolerance in the used materials.

A nice addition to this design is the suggested spacers cut from 160gsm paper. I clamped the paper hindsight it should have laser cut the paper as well, one of the spacers is a little fiddly to hand cut. The parts above is one of the retainers for the Z axis that holds the actuator against the servo and pinion assembly.

One of the more fiddly moments in the assembly was trying to get the encompassed nuts into their slots found the best way was to push it in with you screw driver through the thread pushing downwards.
There was an 'H' shaped piece the is held buy a friction fit it found it needed sanding to fit properly. This once again this is down to different tolerances in the material used.

In the end the who thing came together in under an hour and looks amazing. The instructions are very comprehensive and  easy to follow. As a full kit it would make a great introduction into CNC design and programming. 

At this stage the only thing  I who change is I haven't been able to assemble the PCB yet  mainly because it uses a Sparkfun Pro Micro which doesn't have a standard Arduino pin out and I didn't have one to hand, would deffinatly include a shield type solder joints so it could sit in an Arduino UNO Leonardo ect. 

This is how far I have got with it so far love it. Later on I'll see if I can get it moving. 


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