Test fitting the placement and tolerances on a twis-locking cap for the electronics frame. Two end caps will sandwich the electronics and PCB, with four threaded rods used to keep the assembly in compression. I am trying to keep the initial length of the water tight cylinder to approximately 12 inches (thats the length of 3″ ABS pipe that I have currently) so trying to see if I can fit all the electronics and MCU on the perfboard with the end caps. One of the end caps will have tabs and lock the ensure assembly in place inside the cylinder with the use of a collar that will be glued to the inner wall of the pipe.
I was impressed with the strength of the PLA part but not the print quality. I had modeled the part in Solidworks and printed it with the Printrbot Simple. Due to an extrusion error, the top of the cap ripped off but it still allowed me to test the tolerances and dimensions for inserting the perfboard and checking that all parts have room.
Initial problems: the collar needs to be thinner to allow for the outer diameter of the cap to be lager. Not only do I need to have four holes for the threaded rod to pass through, but I also would like to have electrical connectors build into the caps to allow for easy hook-up of antennas and sensors on the exterior of the cylinder. Tolerances also need to be changed to allow for larger difference in part size when printing. The perfboard fit perfectly into the slot, so that was a good thing. After three prints (none successfully completed) I will redesign and also increase the size of the recessed handle.