18 April 2013

Todays result: A new A.B.S. x-motor end

Wednesday is my self-funded project day, ie I choose not to work Wednesdays so I have time to do my own things. I was disappointed to realise the day of printing I had hoped couldn't happen instead I needed to fix my printer again. During my last print the stepper motors got very hot, hot enough to soften and warp the PLA brackets they were attached to.

Printed a new ABS x motor end and fixed Mendel 90

Looks crap coming off of my old printer. Printed at 0.3m layer height, waves in the walls, very top deformed but repaired with soldering iron. Respect to Nophead for a good printer and model design. Notably easier to repair than other printer

Printed partial neck model missing walls

Eventually I did get one print in before bed time. I printed it to see the result of specific internal structures, but they didn’t even print. Otherwise looks good at 0.2mm layer height & 20mm/s print speed, much better than 0.3mm layer height 50mm/s print speed.

Simple mesh differencing algorithm unusable

The algorithm tries to cut one mesh from another. It works for the tests I have written and can a cube from a Pyramid successfully. However fails on even simple real meshes. It results in backwards triangles, hollow shapes, sharp corners, but there is evidence that it was trying to do the right thing. It assumes that shape is convex and hole cut can be simply filled over – rather than taking shape of cutting mesh. In my case this is acceptable even desirable as all the meshes intersect equally, along corners of the structure. Think of walls of a box where each wall is a rectangular prism, the walls intersect as each rectangle is the full length, width, and or height of the box.
I have looked for some existing functionality that I may be able to use, but haven’t anything that I can use quickly from c#. There are a couple potential libraries in c/c++ but I figured in my simple-ish case it would be quicker to hack together something that will get me across the line than to deal with all the silly problems caused crossing language boundaries and wrapping existing code. I may be wrong on this point.

Motor out of place because of warped PLA

Pink Panther woman neck with (incomplete) structural fill