Rotocaster / Rotomolder made from common parts

thingiverse

THIS IS STILL A WORK IN PROGRESS!\nMain frame components are solid and function perfectly, bearing and bolt mounts too. The feet need to be modified to include more bracing and pulleys/motor are still being fine-tuned(NEMA17 works great but it's the most complicated).\nInstructions are still being worked on and model files may be reorganized or changed.\nThat being said, The machine works well and has produced numerous urethane, silicon and chocolate casts of different types. I'll include some photos later.\nPhotos now include all the needed details, so you should be able to build one from that and help me find any missed mistakes!\nIf you have any problems, I'll try and respond to comments and fix minor issues.\nPLEASE MODIFY THIS DESIGN\nThis was made partly as I wanted something that was easy to make, was flexible in size, didn't use gears and was cheap. My build costs are about AU$35 not including motor.\nI'd love for someone to redo this, a lot more care could be taken to reduce the amount of filament required, especially on the corners. The current design was made to be simple and solid.\nThe aluminium size is common in Australia and I suspect other metric places in the world, however a version may be needed using whatever the nearest imperial size is.\nAn improved version could also reduce the number of bearings to 6 by replacing the single large aluminium with two smaller ones, one either side of a single bearing. Like a 'H'.\nHardware BOM\n3m of 10x20x3mm aluminium. (Larger one was made from 10x20mm bar stock. Heavy!)\nCut list small(150x250): 2x 150mm, 2x 200mm, 6x 250mm, Clean up the ends.Put aside the two pieces of the base and two for the sides.\nIn all other pieces find the center and mark. Put a bearing in one of the 3d printed side(From 'Leftovers' plate), slid onto aluminum until the bearing hole is centered with the mark and drill 8mm holes using bearing as a guide. You could also use 8mm bit just to mark the center, pilot with 3mm bit then drill through with 8mm.\nDeburr each hole. On the holes that will be against bearings, use the countersink bit to shape the hole to allow clearance for the bearing center to turn. This requires quite a deep countersink. See photos.Vertical leg pieces are the same, except the bearing end is aligned with the end rather than center of the aluminium tube. See photos.\nAssemble. The 75mm bolt goes through the handle side. Tape works well to hold the frame together. Once it's aligned, use the 3mm bit to drill into the aluminium through the locking/securing holes. Using screws of the right size, secure together. Long bolts should also work.\n*Use washers as spacers to ensure there is no slop when assembling. 2 washers at the top and 2 at the bottom between the bearings and nut holder were used.\nIf you get to this step I should have more photos/instructions showing the rest.\nMORE NOTES:\nAny place that a pulley attaches to a bolt, screw on a nylock first and drop the pulley over that. It'll stop it from moving when in use. A normal nut then retains it.\nYou may need extra long screws to attach the side/center pulley to the leg piece. I just drilled right through and put a 4mm bolt in place.\nTop belt guides have 2 washers each between the corner and bearing center if you have the guides with pulley insert side inwards. If they are loose, clean out the retaining lip with a knife and a few wraps of tape stop them from twisting and dropping the belt.\nOnce pulleys/guides are in place, THEN add counterweight nuts to the other corners. Make sure the machine can spin freely and has little bias.\nWrap a GT2 belt around them and measure for final size. If you do it with teeth up on the guide wheels, turning the belt over later to ride on the teeth gives a little extra tension if needed, but even slightly loose belts work well.