This is a rack for various cylindrical container that are up to 38mm in diameter. It would work well for 50ml centrifuge tubes, but was originally designed for 38mm storage tubes for expensive nozzles in a machine shop. The storage tubes were previously scattered on the counter-top of the lab with ~$200 nozzles (each) in them. Occasionally the storage tubes would be knocked on the floor and the nozzles inside of them often broke. This rack allows for one safe vertical stored location for all of the nozzles, but also allows for consistent organization of the different types of nozzles used in this lab. This component can be compared to the purchasable part found at the link below; this part costs approximately 1.6% of its purchasable counterpart ($2.08 vs $135.00). 

Link to comparable part for sale online: https://scicominc.com/product/test-tube-racks-heavy-weight-solid-aluminu...

Printer Setup Details (use as a starting point, if desired):

• extrude temperature = 220C
• layer height = 0.15mm
• edge shell thickness = 3mm
• top/bottom shell thickness = 1.5mm
• inner layers print speed = 175mm/s
• outler layer print speed = 100mm/s
• travel speed = 175mm/s
• infill = 100%
• bed type = non-heated
• print material = PLA

Print Details:

• approximate print time with settings above = 4.5 hours
• amount of filament used (per part) = 104g
• cost of print (per part) = $2.08 (assuming PLA is $20/kg)