Computer Case Part

One of the 4 clips that hold the front cover on an old Lian-Li computer case broke, and I decided to print a new one to see if I could make my first useful repair part. Since the part has a shape that could be extruded, it is a candidate for learning how to use inkscape as part of my 3D toolset.

I put the broken part in a flatbed scanner, and scanned the pieces in at 600 DPI:

Then I went to work with gimp cutting and pasting and measuring and rotating and wot-not. Eventually after a lot of fooling around (I remember no details - I tried lots of stuff :-), I eventually came up with this png file that is just the part silhouette:

I followed the instructions in How to Trace an Image Using Inkscape to turn the PNG file into a Path in inkscape, then deleted the PNG file from the document and saved just the Path in an SVG file.

I then installed the inkscape extension from thing 25036 and opened the SVG file in inkscape and ran the extension to save it as a SCAD file.

That gave me an openscad file with some utterly bizzare scaling and dimensions, but the key part of the file was the polygon definition. I extracted just that, extruded it 9.49 mm high (which I measured from the old part), generated the STL file, and loaded it in netfabb to find the ridiculous dimensions inkscape left me with.

The dimensions netfabb showed were 494.33 mm and 321.04 mm, but going back to the PNG file (which is at 600DPI and has the true dimensions as seen by the scanner), the corresponding dimensions I really wanted were 20.96 mm and 13.63 mm, which means I wanted to add a scale([13.63/321.04,20.96/494.33,1]) instruction in the openscad file to get the part to come out the same size as the original I scanned in.

Printing 4 copies of the resulting STL file and comparing them to the original, I get:

All that's left now is to try installing one of them in the case and see if it holds that corner of the cover on properly (or is maybe a bit too thick to work without some filing down first).

It seems to have worked perfectly. Above you see the case, the way an existing clip fits, the hole for the broken clip, and the new clip inserted in the hole, at which point the case cover went back on perfectly, and is now held on at all 4 corners, not just 3 of them.

Go back to my main Solidoodle page.

Page last modified Tue Sep 2 09:00:52 2014