09 Sep

Polargraph prints

Some more recent prints from the Polargraph. This is still running with the original PCB. I haven’t yet updated the software to account for the pin out changes on v2.1.


I’ve seen the Bruce Lee picture plotted on other Polargraphs and it comes out really well, so wanted to see how it compares when plotted on my Polargraph. This was plotted with grid size @ 18 and sample area @ 20 with a Stabilo Point 88 Fineliner 0.4mm with pen tip size set to 0.35mm in software.


Sir Terry Pratchett plotted from a colour photo with grid size @ 12, sample area @ 18 and the same pen and pen tip size as above.

The new gondola design seems to be working really well now.


New Gondola design plotting Albert Einstein.


All three points of force are acting (more or less) around the centre of the pen. Two of the arms require support when printed and were rough when they came of the printer and even after cleaning up they would get stuck from time to time which cause glitches in the plot. The parts were assembled and spun on a drill and manually manipulated for a while and with the addition of some silicone grease they seem to work well now.

The removable pen holder thread dimensions are still wrong. I need to get my 3d printer running again so I can test any changes I make. In the mean time I turned the pen holder down on a lathe and it is currently a press fit, which seems to work really well. I’m tempted to get rid of the thread and redesign both parts to be press fit. That would make them quicker and easier to print.

This design also uses a lot less plastic than my previous version and also allows visibility of the pen tip so you can see exactly what is being plotted. Previously I had to wait a while for the gondola to move on to see if the pen was plotting correctly.

One additional part I need to design is the pen depth setting tool. The idea of the removable pen holder was that I could load it into a jig, drop in a pen which would then correctly set the depth of the pen in the pen holder. Tighten the screw and fit to gondola! That would allow me to do quick pen changes which would be handy if I ever get round to trying plots with multiple colours.


Last Updated on 9 September 2015 by Mark