New Railcore II Bed Leveling Issue
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that is not a flat surface. so you need mesh bed levelling to print on it.
have you got the bltouch with the plastic pin?
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Yes. It's a mic6 bed from 713maker. Its pretty flat. this is I think an issue with rails or the way the kinematics/mechanics are playing with the reprap algorithms.
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Just a thought as I had a similar problem, Do you have G29 S1 in your slicer start gcode?
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My guess is that one or more of the points you are using for the G30 commands in bed.g are being affected by the magnets. Are the magnets in particular places? If so, can you adjust those point to avoid them? Although we suggest one probe pont close to each leadscrew, the exact positioning of the probe points doesn't matter because the levelling algorithm takes account of where the points are.
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One way to test if the magnets are the problem is to change the probe type to P0 for manual probing where you are presented with a jogging window to manually lower the nozzle until it touches the bed. For the 3 points needed for the mechanical auto leveling it wouldn't be too tedious to test. That at least takes the probe out of the equation.
Do you have a straight edge or a square that you could use to eye ball that dip to see if it's actually flat or not? 0.3mm isn't big enough to see just looking at the plate, but it's enough that there should be a visible gap.
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So I took the flex sheet off and tested with a small piece of steel to find the magnets(they are covered on the underside by the heater). I moved the 3 bed.g points a little(projectr3d ships with a plastic probe bltouch are these still affected by bed magnets?). I’ll run more meshes but if magnets are really a problem then that’s fraught with error. Testing a print now.
I decided the flattest thing I had was my large macbook pro so turned out the lights and tried it. I do get a small gap between front and middle of bed and a slightly larger one between middle and back of the bed. Perhaps that’s part of the issue but rail adjustment must have something to do with the way the map falls off linearly toward the back. -
Nothing changed. Prints still don't adhere past middle of the bed. New g29 after 3 g28’s yielded.
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Do you have the mesh compensation active for the print? Is it trying to adjust for that dip or not?
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Tried with and without. After just the g32’s no way. After a 16 point g29 it improves a bit but doesnt correct enough for the dip. When I used mesh with the 256 point I did last night, i got a 225mm circle to look great except for one small section at the far end of the drop off.
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Here is the 4 point g29 they had set up for rail adjustment. It doesn't look bad. Obviously you miss the dip. But does this indicate rails ate reasonable?
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@dc42 Looking at your post above, you said that it doesnt really matter which 3 point are probed fir g32. I realize you said that because if the bed is flat, any 3 points will determine a plane. I then thought why not use that to disprove flatness. I have tried using sets of different points (avoiding the magnets) and can get very different g29 results after the g32’s. Is that not proof that the bed is not flat?
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G31 X2 Y42
can you double check that those values are correct?
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@Veti those are the values I have been using. Basically I am using the config.g, bed.g and firmware I received from Projectr3d.
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Finally got a quality machinist’s large square. The bed has those dips in it. Software rules!
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@4lathe said in New Railcore II Bed Leveling Issue:
@dc42 Looking at your post above, you said that it doesnt really matter which 3 point are probed fir g32. I realize you said that because if the bed is flat, any 3 points will determine a plane. I then thought why not use that to disprove flatness. I have tried using sets of different points (avoiding the magnets) and can get very different g29 results after the g32’s. Is that not proof that the bed is not flat?
Yes, or that the trigger height of the sensor varies with where on where on the bed you probe.
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It turns out they had some bad beds. Sending a new one.
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@4lathe Did the new bed fix the problem?
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@draven much flatter but still a small dip on part of it.
