Nắp GL45 cho nút đậy bằng cao su

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.