Improved y-axis carriage attachment for prusa i3

thingiverse

Too much slack due to high tolerance in smooth rods and linear bearings led my Prusa i3 to noise at any speed and to the build up of ressonance in the y-axis belt even at moderate 40mm/s printing or moving speeds. This ressonance eventually led to the belt slipping off from its pulley. The actual rods provided by Replikeo in my kit was far from smooth and buying low tolerance rods and bearings was too expensive. I even bought some cheap high tolerance bearings in the hope that the original were simply defective but got the same results. I finally decided that to preload the high tolerance bearings was the best solution, given that I had extra bearings now. I have designed these fittings in order to achieve this goal. It works by using three lm08uu running on each smooth rod, the central one being vertically offset by .5mm from the others. The part worked really wel and now my printer speed is being limited by extrusion capacity only at above 65mm/s (if you can go faster, please, give me hints on what could I do to improve printing speeds), and I have yet to find the moving speed upper bound. It is true that I had once reduced my acceleration settings when trying to solve the "y-axis missed steps at moderate speeds" issue. I intend to revert those settings in the firmware and perform more testing. Print Settings Rafts: Doesn't Matter Supports: Doesn't Matter Resolution: 0.25 Infill: above 26% should work Notes: The parts were designed to be printed with the flat part touching the buildplate. Rotate it in your slicer in order to make sure you are printing them in this position. Instructions You will need: 6 m3 nuts and screws 6 lm08uu bearings (you already have three of those in the original setting) Print the parts, fit the nuts (use the screws in order to help pushing them into place), fit the bearings and then fit both parts to the bed carriage. Finally, assemble the y-axis on the smooth rods. The only gotcha is in the latter part where the part labeled "left.stl" (but it is actually side- independent) has no room to long screws and you should try buying shorter than those I'ce got. Sorry, you will have to measure yourself but I guess around 12mm should be good enough. I tagged this as a work in progress because I intend to design grooves in the model in order to solve this issue.