G33 distortion correction

mars0120

I am having trouble with distortion correction. I have my Z axis height and bed level so that I can print fairly well without any correction, but larger prints start to show the distortion and I have bed adhesion problems.

When I run G33 I get a distortion map copied below..

When I attempt to print the nozzle attempts to print several mm above the print bed. When I try to verify the distortion correction manually with the paper shim the nozzle is either 1mm above the bed or it crashes into the print bed. It is not even consistent between homing for the same distortion map. It seems like when the print head gets to 0.5mm above the print head it just goes crazy.

I must have something wrong. Can you help me set this up?

I am sure the Z probe height is -5.7. I am sure the z max distance is 463.8

00:47:26.421 : Z correction disabled

00:47:30.757 : Z-probe:-1.15 X:-50.00 Y:100.00

00:47:33.043 : Z-probe:-1.01 X:0.00 Y:100.00

00:47:35.375 : Z-probe:-0.94 X:50.00 Y:100.00

00:47:38.531 : Z-probe:-1.12 X:-100.00 Y:50.00

00:47:40.829 : Z-probe:-1.02 X:-50.00 Y:50.00

00:47:43.135 : Z-probe:-1.01 X:0.00 Y:50.00

00:47:45.453 : Z-probe:-0.92 X:50.00 Y:50.00

00:47:47.841 : Z-probe:-0.79 X:100.00 Y:50.00

00:47:51.405 : Z-probe:-0.99 X:-100.00 Y:0.00

00:47:53.744 : Z-probe:-0.97 X:-50.00 Y:0.00

00:47:56.077 : Z-probe:-0.95 X:0.00 Y:0.00

00:47:58.424 : Z-probe:-0.91 X:50.00 Y:0.00

00:48:00.778 : Z-probe:-0.89 X:100.00 Y:0.00

00:48:04.351 : Z-probe:-0.89 X:-100.00 Y:-50.00

00:48:06.699 : Z-probe:-0.95 X:-50.00 Y:-50.00

00:48:09.035 : Z-probe:-0.97 X:0.00 Y:-50.00

00:48:11.390 : Z-probe:-0.92 X:50.00 Y:-50.00

00:48:13.722 : Z-probe:-0.95 X:100.00 Y:-50.00

00:48:16.940 : Z-probe:-0.89 X:-50.00 Y:-100.00

00:48:19.311 : Z-probe:-0.92 X:0.00 Y:-100.00

00:48:21.663 : Z-probe:-0.96 X:50.00 Y:-100.00

00:48:23.581 : Info:Distortion correction matrix:

00:48:23.581 : 902, 892, 881, 875, 862

00:48:23.581 : 890, 882, 881, 874, 863

00:48:23.581 : 879, 878, 876, 873, 871

00:48:23.581 : 871, 876, 878, 874, 876

00:48:23.597 : 865, 871, 874, 877, 880

00:48:23.597 : Distortion correction at px:-100.00 py:-100.00 zCoorection:10.812

00:48:23.597 : Distortion correction at px:-100.00 py:-50.00 zCoorection:10.887

00:48:23.597 : Distortion correction at px:-100.00 py:0.00 zCoorection:10.987

00:48:23.597 : Distortion correction at px:-100.00 py:50.00 zCoorection:11.125

00:48:23.597 : Distortion correction at px:-100.00 py:100.00 zCoorection:11.275

00:48:23.597 : Distortion correction at px:-50.00 py:-100.00 zCoorection:10.887

00:48:23.612 : Distortion correction at px:-50.00 py:-50.00 zCoorection:10.950

00:48:23.612 : Distortion correction at px:-50.00 py:0.00 zCoorection:10.975

00:48:23.612 : Distortion correction at px:-50.00 py:50.00 zCoorection:11.025

00:48:23.612 : Distortion correction at px:-50.00 py:100.00 zCoorection:11.150

00:48:23.612 : Distortion correction at px:0.00 py:-100.00 zCoorection:10.925

00:48:23.612 : Distortion correction at px:0.00 py:-50.00 zCoorection:10.975

00:48:23.628 : Distortion correction at px:0.00 py:0.00 zCoorection:10.950

00:48:23.628 : Distortion correction at px:0.00 py:50.00 zCoorection:11.012

00:48:23.628 : Distortion correction at px:0.00 py:100.00 zCoorection:11.012

00:48:23.628 : Distortion correction at px:50.00 py:-100.00 zCoorection:10.963

00:48:23.628 : Distortion correction at px:50.00 py:-50.00 zCoorection:10.925

00:48:23.628 : Distortion correction at px:50.00 py:0.00 zCoorection:10.913

00:48:23.628 : Distortion correction at px:50.00 py:50.00 zCoorection:10.925

00:48:23.643 : Distortion correction at px:50.00 py:100.00 zCoorection:10.937

00:48:23.643 : Distortion correction at px:100.00 py:-100.00 zCoorection:11.000

00:48:23.643 : Distortion correction at px:100.00 py:-50.00 zCoorection:10.950

00:48:23.643 : Distortion correction at px:100.00 py:0.00 zCoorection:10.887

00:48:23.659 : Distortion correction at px:100.00 py:50.00 zCoorection:10.788

00:48:23.660 : Distortion correction at px:100.00 py:100.00 zCoorection:10.775

00:48:23.665 : Z correction enabled

Repetier

Are we talking about a delta printer?

Anyway -5.7 mm z probe height sound very wrong. That would mean when your z probe triggers, the extruder is 5.7 below bed level. With FSR/springs small negative numbers are possible but 5.7mm is extreme.

Furthermore G33 L0 should show a distortion matrix that swings around 0 not in range of 10-11mm. It is a correction of zero.

Also make sure that z home goes back from z max a few mm, on deltas maybe even 20mm to prevent crashing into endstops.

So first check eeprom and check bed coating is 0, so we have not to watch for that. Disable distortion and do autolevel G32 S2. If you then go to G0 X0 Y0 Z0 your extruder nozzle should be very close to the bed. Better to go first to Z20 and then slowly lower as we are searching correct height. Once you touch bed the z must be added/subtracted from z probe height. Only once G32 S2 creates satisfying results you can run G33. Later on you can modify heights With G33 Xpos Ypos Zcorrection if it somewhere not as expected, especially with deltas where points were extrapolated to get a bigger circle.

mars0120

Yes it is a delta.

My probe triggers when the print nozzle is 5.7 mm above the print bed. I had the sign wrong on that field. Below is the more appropriate distortion correction matrix.

The nozzle no longer goes crazy but it still rides too high above the build plate. If I disable distortion correction the printer works fine for prints around 100mm square in the center of the plate. With distortion correction on the nozzle is always too high. It won't even print a 10mm square.

Do I have to do G32 S2 prior to G33? I have my print bed very level manually. Will a manual bed level not work?

09:53:26.883 : Z correction disabled

09:53:32.218 : Z-probe:15.43 X:-50.00 Y:100.00

09:53:36.558 : Z-probe:15.48 X:0.00 Y:100.00

09:53:40.941 : Z-probe:15.63 X:50.00 Y:100.00

09:53:46.167 : Z-probe:15.40 X:-100.00 Y:50.00

09:53:50.499 : Z-probe:15.55 X:-50.00 Y:50.00

09:53:54.887 : Z-probe:15.57 X:0.00 Y:50.00

09:53:59.289 : Z-probe:15.65 X:50.00 Y:50.00

09:54:03.739 : Z-probe:15.79 X:100.00 Y:50.00

09:54:09.357 : Z-probe:15.48 X:-100.00 Y:0.00

09:54:13.744 : Z-probe:15.60 X:-50.00 Y:0.00

09:54:18.132 : Z-probe:15.54 X:0.00 Y:0.00

09:54:22.521 : Z-probe:15.64 X:50.00 Y:0.00

09:54:26.945 : Z-probe:15.71 X:100.00 Y:0.00

09:54:32.570 : Z-probe:15.55 X:-100.00 Y:-50.00

09:54:36.942 : Z-probe:15.52 X:-50.00 Y:-50.00

09:54:41.310 : Z-probe:15.50 X:0.00 Y:-50.00

09:54:45.696 : Z-probe:15.59 X:50.00 Y:-50.00

09:54:50.101 : Z-probe:15.66 X:100.00 Y:-50.00

09:54:55.374 : Z-probe:15.55 X:-50.00 Y:-100.00

09:54:59.746 : Z-probe:15.52 X:0.00 Y:-100.00

09:55:04.127 : Z-probe:15.52 X:50.00 Y:-100.00

09:55:07.065 : Info:Distortion correction matrix:

09:55:07.065 : 28, 22, 18, 6, -9

09:55:07.081 : 24, 12, 10, 4, -7

09:55:07.081 : 18, 8, 13, 5, -1

09:55:07.081 : 12, 14, 16, 9, 3

09:55:07.081 : 8, 12, 14, 14, 10

09:55:07.081 : Distortion correction at px:-100.00 py:-100.00 zCoorection:0.100

09:55:07.081 : Distortion correction at px:-100.00 py:-50.00 zCoorection:0.150

09:55:07.081 : Distortion correction at px:-100.00 py:0.00 zCoorection:0.225

09:55:07.081 : Distortion correction at px:-100.00 py:50.00 zCoorection:0.300

09:55:07.081 : Distortion correction at px:-100.00 py:100.00 zCoorection:0.350

09:55:07.096 : Distortion correction at px:-50.00 py:-100.00 zCoorection:0.150

09:55:07.096 : Distortion correction at px:-50.00 py:-50.00 zCoorection:0.175

09:55:07.096 : Distortion correction at px:-50.00 py:0.00 zCoorection:0.100

09:55:07.096 : Distortion correction at px:-50.00 py:50.00 zCoorection:0.150

09:55:07.096 : Distortion correction at px:-50.00 py:100.00 zCoorection:0.275

09:55:07.096 : Distortion correction at px:0.00 py:-100.00 zCoorection:0.175

09:55:07.112 : Distortion correction at px:0.00 py:-50.00 zCoorection:0.200

09:55:07.112 : Distortion correction at px:0.00 py:0.00 zCoorection:0.163

09:55:07.112 : Distortion correction at px:0.00 py:50.00 zCoorection:0.125

09:55:07.112 : Distortion correction at px:0.00 py:100.00 zCoorection:0.225

09:55:07.112 : Distortion correction at px:50.00 py:-100.00 zCoorection:0.175

09:55:07.112 : Distortion correction at px:50.00 py:-50.00 zCoorection:0.113

09:55:07.112 : Distortion correction at px:50.00 py:0.00 zCoorection:0.063

09:55:07.128 : Distortion correction at px:50.00 py:50.00 zCoorection:0.050

09:55:07.128 : Distortion correction at px:50.00 py:100.00 zCoorection:0.075

09:55:07.128 : Distortion correction at px:100.00 py:-100.00 zCoorection:0.125

09:55:07.128 : Distortion correction at px:100.00 py:-50.00 zCoorection:0.038

09:55:07.128 : Distortion correction at px:100.00 py:0.00 zCoorection:-0.012

09:55:07.128 : Distortion correction at px:100.00 py:50.00 zCoorection:-0.088

09:55:07.146 : Distortion correction at px:100.00 py:100.00 zCoorection:-0.113

09:55:07.150 : Z correction enabled

Repetier

Your problem is in deed manual calibration. In this case G33 compensates for bumps + difference to G32 S2 and that is apperently 0.1mm or so on average. This also means your z probe height is 0.1mm too high. G32 S2 must be the height you'd also set manually. Then do G32 S2 and G33. If your in total a bit too high/low you could adjust using bed coating to go up or down in total.