Unsolved mesh bed compensation not applying correct corrections
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@necrorat said in mesh bed compensation not applying correct corrections:
should the m208 also have these figures in?
No, M208 should define your reachable area. It's normal for the lead screws to be outside the print area. Your probe points should be as close as possible to the lead screws.
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i dont think there should be a G29 S1 in the bed.g
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M557 X23:270 Y9:265 P2 ; define mesh grid
P2 will not result in a usable mesh.
try S15
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for the p parameter it was originally at 8 and behaved exactly the same. i am using two now to speed up iterations and to see if there is an improvement, so far the exactly the same behaviour despite the amount of probed points. as for the bed.g ill remove the G29 and see if that helps
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@Phaedrux that was my understanding and have set them as such. the probe point is about 10mm in from the edge of the bed so as close as reasonably possible
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one further question when taking the measurements for the where the leadscrews are positioned should i be taking the measurements from the nozzle or from the probe? (nozzle is 0,0)
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I'm not sure I understand what you mean. The lead screws are fixed in relation to the bed, so their position is absolute. 0,0 is a point on the bed, the nozzle/probe/printhead is relative to that. The lead screw position would be relative to the 0,0 position in absolute coordinates.
Does that make sense?
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@Phaedrux so when i home my machine the print head moves to 0,0 which lines up with the printer nozzle being in the bottom left corner. what i wanted to check is that the bed compensation calculations where been done relative to the nozzle not the probe as the probe is offset approximately 23mm from the nozzle. so the above values would of been off but after digging and as you said the calcs are done from the nozzle for all intensive purposes and that is how i have it configured at the moment.
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so an update to the issue. spent all of this evening re checking that the machine is as square as reasonably possible and have levelled the bed to as close as i can get it to perfectly flat
but now when i go to load up the height map it gives me the error:
G29 S1
Error: G29: Failed to load height map from file heightmap.csv: failed to read line from fileat this point i dont really need mesh compensation as get ting very nice first layers without the mesh but for completions sake i want to get everything working as intended and iron out the few areas that are slightly more squashed than others on the first layer. should i try reducing the number of probed points to try and get it to accept the height map? or just any steers in the right direction would be highly appreciated.
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Can you upload that Height map. CSV?
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@Phaedrux heightmap.csv there you go mate, appreciate the help so far!
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I don't see anything in particular wrong with that file. Try deleting it from the SD card and re-running G29
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so deleted the file and reduced the number of probe points and it seems to of accepted the file now,but it still seems to be not applying the mesh correctly. there are inconstant very small gaps between the extruded lines in a couple of patches on the bed so that leads me to believe that something i have borked up in my config. ive checked my extrusion multiplier and calibrated my e steps so at this stage it must be something in my config or associated files.
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@necrorat said in mesh bed compensation not applying correct corrections:
inconstant very small gaps between the extruded lines in a couple of patches on the bed
that is either a problem with under extrusion or backlash in your printer. not a problem with mesh bed leveling.
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@Veti 90% of the bed layer is perfect there are two patches where the gaps are observed so if it was under extrusion or backlash would it not be consistently like that all over the bed with mesh levelling working as it should?
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post a picture
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@necrorat said in mesh bed compensation not applying correct corrections:
The image seems to show a bowed gantry. What areas are not touching the bed?
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not the best pictures but best i can do at the moment.the main area is the region 3 threes what appears to be a island where the print head is too far from the bed
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Where are those locations in relation to the heightmap?
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I see you're using the BLTouch. You can attempt to get a bit more accuracy and repeatability out of it by modifying your M558 a bit.
M558 P9 H5 F60 T6000 A10 R0.75 S0.003 B1Slower probe speed, with repeated attempts if 2 consecutive probes don't match to within a tighter tolerance. Probing will take longer because of the slower dive height and it will do at least 2 probes per point. But you will be far less likely to get outliers.
