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Fusion 360 Assembly: A360

 

I am still uploading my drawings and parts. Fusion 360 is giving my some headaches sharing the project files. I will upload STLs once I have them exported.

 

The single 20x20 offset to the rear allows you to slide the t-nuts down the frame for the Z motor bracket and the lead screw supports. This makes assembly a lot easier than trying to hit a t-nut behind a printed part on a vertical structure, since you can pre-assemble the parts with t-nuts on them.

 

The banding was due to some earlier designs of this printer used a hanging z lead screw. Once I flipped it and secured the top with thrust bearing as tight as possible, the banding went away.

In my case I am using the spiral cut aluminum motor mount. They were expanding and contracting like a spring causing z layers a different thicknesses.

Yes I did use a different printer, but now the issue is solved.
Nearly all of the parts for this printer we're printed by itself. In the interim, I used temporary aluminum extrusions for parts like the y end caps and open builds part store motor brackets or wood blocks.
This was I was able to get a working printer with 0 printed parts, and gradually print improvements. The secured leadscrew and better belts have been the biggest quality improvements so far.

 

It is fairly heavy, due to the mass of the dual extruders and motors. I am running my z motors wired in series to compensate.

This eliminated a step skipping issue I had when the z motors we're wired in parallel. The banding issue was partially caused by unsecured leadscrew and partial by missed steps.

Currently I print with no problems at 120mm/s with PLA as long as I lay down the first layer at 30-40mm/s.
Some early versions had horizontal banding that was caused by a belt that was too stiff. I was experimenting with "zero" stretch belts, and they conducted too much vibration, especially at high speed. The slightly stretchy belts have a damping effect.

 

Very careful measurements with a square. It actually wasn't too hard, just requires a little patience and a few test prints. You can measure diagonals on test prints to figure out if you are out of alignment.