I found that the base for the conduit and motor mounts is too thin. (snapped one, others flex a bit.) I think it should be revised to be about the thickness of the motor mount plate. It is actually quite a bit of weight hanging from them.
I didn’t have any issues with mine. The first place I’d look is your slicer settings. Add layers and/or infill and see if this helps. Also, snug is good for fasteners. Over-tightening the screws/bolts can also cause printed parts to fail.
I looked at it a bit further. Seems to have printed about right, but the base is still only about 1/3 the thickness of the motor mount, and there are no bolt down tabs on the opposite side, so that makes even more leverage against that thin surface. Mine snapped when it was right-side up when I dropped the corner of the table a bit hard.
I can tell from where it snapped that it flexed and created a shear-line alongside the bolts.
You mean I’m not supposed to hear that crunching sound as I snug the bolts? (joking!) I know about properly snugging the bolts up.
I would still recommend a thicker mount plate and now, after further analysis, additionally add a screw tab on the opposite side of the base to prevent torque fatigue.
Attached a photo
I rotated the print so the base is on the bottom. That gives me about 15 layers rotating directions. With the bottom on the side I had no infill. Just a spiral per layer. That is probably why it split!
So, note to others, rotate the mounts so the bolting side is down when you print!
It should be printed rail side down or the rail sleeve with not hold well. I would love to do a revisit of the Zen soon but this is the first I have heard of this issue. I have added it to the Zen revision notes and will take a look when I can.