Y-axis assembly issues / frame skew
I'm having assembly issues from the very beginning while trying to assemble the Y-axis frame (literally the first assembly step). I cannot get the frame together in an un-skewed state once all pieces are together and all fasteners are torqued. Once fully assembled, the far corner of one of the longer 80/20 pieces is right about 2mm off the flat surface. The instruction manual suggests that anything under 2mm here is fine, so I'm close to that, but it just doesn't look right and I have a hard time believing that this won't cause issues with calibration and builds if I ever get that point.
I've tried a multitude of things to remedy this to no prevail. My flat surfaces are flat (large welding table, granite kitchen counter). I've used a torque wrench on everything, stepping up torque on each fastener incrementally. I've tried different torque patterns. I've disassembled, swapped/flipped components and reassembled. I've assembled each component in the most-free state possible, and I've tried the clamp everything in place approach. I've tried a few different order-of-assembly methods than what is in the manual.
Has anyone else had issues here? If so, what did you do? I emailed Prusa a few days ago, have yet to hear back anything...
Thanks
RE: Y-axis assembly issues / frame skew
Don't put the frame on your surface. Just two of the side pieces.. Tighten those two then do the other side.
My frame extends below the side pieces. That was a big so what. Only the side pieces have to be parallel.
You may die of old age before Prusa EMail gets back to you. Only Chat works well.
RE: Y-axis assembly issues / frame skew
@robert-rmm200
I understand what you are saying, however I'm already using the 80/20 extrusion pieces (side pieces) as my basis for saying things are skewed. The end plates and the center plate stick down below the 80/20 pieces, but I've actually got two identical levels clamped down to my welding table to provide two flat and coplanar surfaces for only the 80/20 extrusions to sit on (at the ends, near the front/back plates), and they are indeed skewed / not parallel.
RE: Y-axis assembly issues / frame skew
You have the equipment to make the ends square (assuming the holes are correct), but I think I would just contact Support.
If you modify the laterals, that probably screws your warranty.
Click EShop above, log in, then click the Chat button. Have pictures available that demonstrate your skew.
RE: Y-axis assembly issues / frame skew
Getting the same problems. Open the box, grab the manual and immediately get the 'you've just wasted a lot of money on junk' feeling on step 1 after not being able to get the frame to sit flat. On top of that, the chinesium bolt heads have all worn out from the constant adjustments. So now have to order some decent bolts and figure out how the hell to get this thing to sit flat.
Is there an actual way to get this thing to sit flat? nothing I've seen in the manual or on youtube seems to work. As soon as you tighten it up, it twists.
RE: Y-axis assembly issues / frame skew
@not-needed
Well - despite the parts not being precision cut extrusions, they are generally pretty close. I tried doing the car frame trick to adjust the level but later figured out the more important aspect is for the two end plates to be square and level. Good thing, too: those extrusions are really hard to tweak. I found that by swapping ends of the frame extrusions, and using what little wiggle room there is in the screw holes, I finally got the warp down to acceptable. It still wasn't perfect, but I was at a point of 'good enough.' It calibrated just fine, parallel and true and well within the limits shown on the cal results. Though, in the end, I had to go in and tweak bed level correction to compensate for the less than perfect frame.
As for the screw quality and heads stripping? I used up a spare or two finding out the torque spec given for them was, well, imaginary? At least the heads strip rather than breaking a screw off in the extrusions.
On a positive note, once everything is together and working there are several ways to adjust for a slightly off frame. For example, many install the Nylock mod for bed leveling. It can cure a multitude of frame and bed imperfections. Plus, it's easy to do.