GL45 cap for rubber stoppers

Smaller diameter hole compared to original red Duran caps prevents damage to the edge of the stopper.

I've redesigned the cap with medium pressure (2-4 bar) and autoclavability in mind. I've increased the thickness of the upper flat part of the cap to prevent bulging given the excess pressure in the bottle, especially with carbonate-rich media, can be as high as 4 bar.

Printing recommendations: 

100% infill, especially across the flat part, 2.5-4 mm thick walls.

0.6 mm nozzle and 0.2 mm layer height are sufficiently precise for printing the thread.

For printing, rotate the cap flat side down.

Important notice:

For autoclavability, use filaments that remain strong up to at least 121 centigrade.

Don't use PLA, PETG, HIPS or ABS. I had a good experience with glass-filled polypropylene (Nova PP-GF) enduring at least 10 cycles of autoclaving at 1.5 bar (127 centigrade) with no visible damage or bulging. Maybe, some high-temperature Nylon- or POM-based composites will also work.