Replacement pen body for a Pilot Parallel pen

I just completed my replacement pen body for the PIlot Parallel. I thought you all might be interested. Any thoughts/questions?

http://mattharvest.com

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A bunch of notes on what I learned:

  1. Printing threads: matching the existing thread on the nib was the hardest part: ultimately I recreated the “original” in Fusion 360, then created a ‘nut’ profile by subtracting that from the pen body. I then scaled the pen body horizontally by 1%. This allowed enough gap to thread the pen without an issue. I did basically the same thing after putting the threads on the outside of the pen.

  2. Resolution: this was printed at 0.1. Since I was wet-sanding/polishing it afterwards, there was no gain from the higher resolutions. Those threads are amazing, and they’re doable at the lowest resolution on the Form+. You can’t even try to print such threads - seven loops in 0.5cm - on most other printers.

  3. Angle. I ultimately printed both the top and bottom almost entirely vertical, just offset by 5-10 degrees. This was the best way to avoid having tons of supports (or internal supports) while allowing the structure to form.

  4. Patching. When I printed the bottom, there was a small defect at the base of the threads. To fix it, I dabbed a tiny bit of raw resin on it, and put it back in my UV tank (an acrylic jar wrapped in UV LEDs, basically). This cured that raw resin just perfectly as if there had been no defect.

  5. UV Curing: as noted above, I have a UV tank I used to finish the pieces. I printed them normally, then put them into the IPA bath. However, I didn’t let them soak: I used an old soft toothbrush head and my gloved fingers to gently rub the surface and remove any residue. I kept them in the IPA for as little time as possible. They were then cured for 3 minutes in the UV tank to harden them.

  6. Finishing: they were wet sanded at two grits, before being polished with the 1-2-3 Novus solutions.

Wow, that’s really cool! We’ve seen quite a few examples of wet sanding clear resin to make it more transparent, but this is a really cool application to get that injection-molded look. Nicely done!