I made these Pen Cups to replace the stock omes on my HP DraftMaster RX plotter because the original ones didn't work well with the replacement Gel Pens I made for the plotter ( https://www.thingiverse.com/thing:6101844 ). The old cups occasionally would allow the pens to leak as their tips would rest on the bottom of the cups. These new cups are deeper so they rest on the 3D printed portion of the pen, providing a seal and allow the tips to be suspended.

I printed the new cups using TPU.