HICTOP i3 clone Y-axis bronze bushing holder by mcdanlj

Last crawled date: 3 years ago

The SCS8UU bearing blocks that came with my acrylic HICTOP i3 clone were not particularly precise and have bearings that chatter, leaving artifacts in the print. I bought two kinds of bronze bearings for smoother movement; graphite inserts and oil-impregnated self-lubricating bronze. However, I found that when I mounted them in printed SCS8UU-style pillow blocks, they were insufficiently aligned and over-constrained and the print bed did not move smoothly. This design resolves that by printing one piece for the left side of the bed where two SCS8UU blocks are normally mounted, and by constraining a much shorter section of the individual bushings.
There are several variants in the openscad source. The default variant uses screw-on brackets; the alternative variant uses clips to hold the bushings. For either variant, you can print two long blocks, one for each side (recommended) or one long and one short block, following the pattern of the bearings provided (more yaw forces from uneven friction).
The long bearing holders should be attached by only four (or perhaps fewer) screws. If youo print two long holders and use one on each side, fasten one with the outer screws and one with the inner screws to match the holes in the "frog."
I used an M4 spiral tap to cut the threads; it clears plastic out better than a straight flute tap. You can use melt-in inserts instead, but sufficient alignment may be very hard to maintain, and the base is thick enough for working plastic threads in my experience so far.
Although I have configured the source to work with the Customizer, the Customizer fails to display, probably because it takes too long to render. Your milage may vary, but you'll probably want to modify it in OpenSCAD locally.
I keep the source files at github