Skewed frame or warped bed?
Just saw my first mesh and see a significant issue. I'm not sure if I should troubleshoot frame issues or bed warp.
What do you think?
VCore 3.1 500mm. OpenFront mod. Stock bed.
32 Replies
both front corners have to be lowered (will bringthe back (blue) up. ... might smooth out the ridge down the middle a bit as well
rival-blackOP•2y ago
Can you go into a bit of detail? Are you implying this is just a bad z tilt?
no. Your Y rails are not level with the bed. see the video in the thread at https://discord.com/channels/582187371529764864/1066067062759358524/1066067062759358524
rival-blackOP•2y ago
Got it. Thanks for the troubleshooting path forward. Since my frame measures square (from what I can tell), am I moving the Y-rail extrusions sub mm or a few mm at a time, you think?
+/- .3 to 3mm ymmv. A trick.. some people have used a spare 90 degree bracket, inserted s screw and nut and used it as a 'jack' or at a minimum, a reference 'stop' for moving the beam, up/down
I guess 'technically' the one end adjustment would be 1/2 the distance of the differential between the two end points of your mesh difference corner to corner for that side
rival-blackOP•2y ago
Amazing. Such a huge help. I'll provide updates asap. The jack idea is great.
rival-blackOP•2y ago
Getting there, I think
it you get that front left corner down more (lifting the left rear) and now the two front corners are level, the next trick is simply putting a couple layers of blue painters tape on you magnetic sheet under the build plate across thos low back corners
rival-blackOP•2y ago
Ugh, it seems like the dipped corner keeps switching
back left to back right and vise versa
Get your two front corners level. remember.... lowering the right front will raise the left rear (see-sawing on the rear and front left pivots) and visa-versa
rival-blackOP•2y ago
Won't the two front corners always be mostly level? In the video you suggested (which has been great), he says that the two front ones will "always be level". Timestamp: https://youtu.be/h7ZTq2dDTkM?t=1138
3D Printers & a Whiteboard
YouTube
RatRig V-Core 3: How to Get a Square Frame
This video is for those who struggle getting bed meshed with their RatRig V-Core 3.
Please feel free to jump to the chapter you are interested in.
0:00 Intro
1:05 about the v-core 3 frame and bed leveling
8:26 what to take care of in the building phase
9:17 the right square
10:09 build tips
16:50 adjusting the frame according to your bed mesh
...
rival-blackOP•2y ago
That's the only thing throwing me off
So, the issue now is I have moved the front corners up 2 mm and I still see basically the same warp in the mesh
It's certainly out of square now.
Yeah, 4mm higher now in the front than in the back
So I'm clearly doing something wrong
I moved the y extrusions back into square and I'm probing again to start over.
But I don't know how to proceed.
rival-blackOP•2y ago
At least my untuned mesh isn't AS bad as it was, though this is cold so I dunno
well you can see in your graph, the three 'high' spots are the three pivot mounts (arms) Drop those two front corners a tad more and see if the rears come up.
rival-blackOP•2y ago
I got so excited for my new Beacon Probe, but after my first mesh I remembered that I had this issue.
rival-blackOP•2y ago
I'm almost fully convinced this is bed sag due to the stock 500mm x 6mm bed.
Its almost certainly not. What variance? The bowing from corner to corner is almost always bowing of the rails. Your X rail is bowing down in the middle, your Y rails are bowing up. There is a way to correct that somewhat but I cant see what variance you had in that mesh. Meshes also almost always look worse than they actually are. On a 500 you're going to have quite a bit more variance than on a 300 for example.
It's a royal pain.... but you can try rotating your X gantry rail 90 degrees to minimize the bow in the Z axis. A Y axis bow is a lot less troublesome. Possibly noticeable, but a lot less of an issue.
rival-blackOP•2y ago
Variance is .6mm, sorry for the delay in response.
Do you mean 180 degrees?
I tihnk thats what he meant, turn em upside down basically to counter the bowing.
Its interesting, share the results if youre going to do that 😉
If I were you I'd bring the front 2 corners down, or the rear up.
rival-blackOP•2y ago
I'll try this again soon, but when I tried this in the past it didn't quite work. I moved the front 4mm down out of square and the mesh only looked marginally better. Like, going from .5mm deviation to .4mm.
Right now it definitely measures as pretty darn close to square.
4mm made no difference? :S
how can you even move them that much?
rival-blackOP•2y ago
Surprised me too. I was moving incrementally over like, half a day. When I measured squareness it was out of wack.
There is less than .1mm deviation from front right corner to front left, so I don't think I have X sag.
measure the corners from back to front
rival-blackOP•2y ago
What do you mean, specifically?
I meant X is not a problem, its Y front to back. I don't know what else to suggest. You could try moving the back extrusion up if bringing the front down doesn't work but I am more puzzled by the fact that 4mm didn't make any difference. I find that really strange but then again, Im no expert, just trying to help with what I know.
and I just realize I have been giving you the wrong advise (apologies!). I didn't pay attention to the X and Y scales, but in the latest screenshot you had turned your bed around. I should have seen that, my bad. Your front is way too low so you need to move that up instead of down.
rival-blackOP•2y ago
My fault for turning it around halfhazardly
rival-blackOP•2y ago
rival-blackOP•2y ago
This is after raising both fronts of my Y beams up 3mm.
Basically looks identical to how it started.
Same story as last time. Raising the front just does not address the issue. It's very frustrating that this is so far the only advice I've gotten. 😦
@nebulator (hope you dont mind me "@ing" you)
rival-blackOP•2y ago
This is a mesh taken after re-squaring the front. The variance got worse by .1mm, but the fronts moved over 3mm.
rival-blackOP•2y ago
So if I need to move 3mm for ever .1mm of correction, my front will be a dozen mm higher than my back.
This is why I don't think moving the front up will help me.
I dont know what to tell you, sorry.