A350 dual carriage Y axis mod

Some custom Y-axis mod I did to reinforce the bed at the most forward/back of the heat bed, please note this does not make the build surface bigger, this is only to add a second set of sliding carriages to the Y-axis. This was done to remove the “bounce” I noticed when the Y axis changed direction, on top of that it will make the furthest edges of the build plate stronger and reduce the stress on the center mounted carriage when using the CNC router to full dimensions.

The carriages are about 230mm apart (can’t remember the exact dimension currently), and are missing the lead screw nuts (as the lead screw was never changed to be longer, also reduces stress on the stepper motor and was redundant to power both carriages). The extensions are 256mm long and use a new 5mm guide rail made of hardened drill rod material. I had also made a new bed to go under the heated buildplate out of 6mm aluminum with a Plexiglas isolator to keep the heat bed from shorting out on the aluminum.

Please note all these mods have voided my warranty, which I have no issues with, but I really like the more stable build platform.

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Thanks for the share.

I had some problems with print stability myself and also tracked it down to Y axis instability. It led me to rotating my prints 90 degrees so that large movements would be lined up in X. This certainly helped. But it points out that driving that huge bed by the center is not so great, even with two rails. I would be particularly concerned with CNC operations at the limits of the Y travel of the A350 as shipped.

I had another idea that might be more practical for SnapMaker to pursue: a passive roller stabilizer in the center between the two rails. I don’t think it would be necessary for it to project out beyond the base as your mod does. Just a smooth accurate surface in the center of similar length as the active rails, combined with some rollers on the bottom of the platform would do the trick I think. If there were three rollers (front, middle, back), then two would always be in contact to provide Y stability. I suppose this could be to the outside of either Y rail instead of the center with nearly the same benefit.

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I think something like your idea would indeed be really good. I would even go to the length of havind four or five rollers to ensure a steady support.