Second part arrives

The transparent visor part arrived yesterday from Shapeways.


It’s not very transparent, but apparently with sanding and polishing it becomes clear. It’s also very fragile – a piece broke off when I tried to attach it to the first part and it had to be glued back on.

Now that I’ve got my hands on the part I can see a few things that need improving.

  1. The visor needs to be thicker. It’s currently 1.2mm thick, and will be difficult to sand and polish without breaking. At least 1.5mm next time.
  2. It needs a shorter focal length. The visor sits too far forward on the brim of the cap and doesn’t really provide fully field-of-view coverage. Shortening the focal length will move it back and increase its curvature, hopefully solving both problems.
  3. The attachment mechanism needs rethinking. The tolerances are too tight – this can be fixed with sanding, but that’s not suitable for mass production. It can fail when the visor material is too fragile. It’s too complex for injection moulding. And it partly obscures the phone’s screen.

Still, I’ll proceed with what I’ve got. Get the visor sanded and polished, then hopefully mirror coated, and see if it works.


First part arrives

The first part has come back from Shapeways. I actually ordered this a week after the visor component, but there has been a backlog on the machine that prints transparent materials, so it won’t be in until early next week.


Not bad. Near as I can tell it’s exactly to specifications and it feels pretty tough.

Two related observations …

  1. Shapeways, when you send me a part that fits in a 12 x 8 x 3cm baggie, please don’t pack it in a 20 x 15 x 12cm box and charge me $20 shipping. Use a smaller, cheaper, box.
  2. I got home to find a UPS card in my letterbox. Oh no, I thought, another game of courier tag. But no, they’d left it at a nearby 7-Eleven for pickup. Brilliant, UPS you guys rock! Fedex, please do something similar.

Final design

Once you get the hang of FreeCAD’s features you can make some nice-looking designs.


The STL file for the dark green attachment mechanism has been sent to Shapeways, and should be returning in physical form in a few weeks. Then we’ll see if the pieces fit together.