A20T Auto Levelling Issues
Posted: Fri Apr 17, 2020 5:44 am
I have recently bought an A20T and fitted the 3DTouch sensor and updated the firmware with 1.1.8 with 3D Touch sensor hex file downloaded from Geeetech website. The board is GT2560 V4.0, FW Ver: 2.1, HW Ver: V2.10. I have tried searching for the source code but I am unable to find it anywhere.
I am having issues with the repeatability of the Auto Home and Bed levelling functions that are resulting in poor 3D printing.
I have designed a very thin 50x50x0.3mm square so that I can just test to see how the first layer is laid.
I have read (and seen on YouTube) elsewhere that the Start GCode needs to have G28 and G29 included for it to work so I tried that but was having variable results. Sometimes it worked OK, but sometimes the head was too low (roughening the surface) and then too high (roping effect).
I used the Repetier Host v2.1.6 to send manual and scripted commands to the A20T. I sent the M420 V command to give a verbose listing of autolevel status and the bed levelling and generated some scripts to do some experiments.
The first script was G28 and G29 repeated four times. These are the results I got:
09:46:59.144 : N17 G28*37
09:46:59.144 : N18 G29*43
09:46:59.144 : N19 G28*43
09:46:59.144 : N20 G29*32
09:46:59.144 : N21 G28*32
09:46:59.145 : N22 G29*34
09:46:59.145 : N23 G28*34
09:46:59.145 : N24 G29*36
09:48:35.921 : Bilinear Leveling Grid:
09:48:35.923 : 0 1 2
09:48:35.924 : 0 +0.188 +0.237 +0.131
09:48:35.924 : 1 +0.038 -0.010 -0.012
09:48:35.926 : 2 +0.218 +0.237 +0.221
09:50:12.637 : Bilinear Leveling Grid:
09:50:12.639 : 0 1 2
09:50:12.640 : 0 +0.149 +0.168 +0.189
09:50:12.640 : 1 +0.007 +0.029 +0.051
09:50:12.642 : 2 +0.173 +0.156 +0.239
09:51:49.476 : Bilinear Leveling Grid:
09:51:49.477 : 0 1 2
09:51:49.479 : 0 +0.406 +0.149 +0.184
09:51:49.479 : 1 +0.094 +0.124 +0.075
09:51:49.480 : 2 +0.255 +0.285 +0.281
09:53:26.309 : Bilinear Leveling Grid:
09:53:26.310 : 0 1 2
09:53:26.311 : 0 +0.098 +0.098 +0.024
09:53:26.311 : 1 -0.075 -0.104 -0.104
09:53:26.313 : 2 +0.073 +0.152 +0.108
The second script was G28 and four G29s. These are the results I got:
10:11:33.742 : N25 G28*36
10:11:33.742 : N26 G29*38
10:11:33.742 : N27 G29*39
10:11:33.742 : N28 G29*40
10:11:33.742 : N29 G29*41
10:13:10.545 : Bilinear Leveling Grid:
10:13:10.547 : 0 1 2
10:13:10.548 : 0 +0.135 +0.153 +0.106
10:13:10.548 : 1 -0.047 +0.049 -0.069
10:13:10.550 : 2 +0.131 +0.197 +0.189
10:14:30.671 : Bilinear Leveling Grid:
10:14:30.672 : 0 1 2
10:14:30.673 : 0 +0.152 +0.255 +0.153
10:14:30.673 : 1 -0.001 +0.066 -0.067
10:14:30.675 : 2 +0.103 +0.179 +0.216
10:15:50.795 : Bilinear Leveling Grid:
10:15:50.797 : 0 1 2
10:15:50.798 : 0 +0.285 +0.125 -0.060
10:15:50.798 : 1 -0.102 +0.038 +0.148
10:15:50.800 : 2 +0.163 +0.356 +0.223
10:17:10.744 : Bilinear Leveling Grid:
10:17:10.745 : 0 1 2
10:17:10.746 : 0 +0.254 +0.189 +0.059
10:17:10.746 : 1 -0.118 +0.077 -0.002
10:17:10.748 : 2 +0.049 +0.312 +0.265
Since there was no physical adjustment made to the bed levelling I would have expected the grid readings to be identical (within a small tolerance) each time - but they are not. In Script 1 the readings for 0,0 vary from +0.098 to +0.406 which is a range of 0.308. In Script 2 the readings for 0,0 vary from +0.135 to +0.285 which is a range of 0.150.
I had similar results when the printer was powered on or the reset..
I then reset the printer and did a manual 'Auto home' followed by a manual 'Bed leveling' and 'Store settings' to store the levelling results to EEPROM. My Start GCode was changed to:
G28 ; Home extruder
M420 S1; Turn on Bed Leveling and use stored results from EEPROM
M420 V ;Display Bed Leveling Status
This performed 'Auto home' and the M420 S1 used the bed levelling values stored in EEPROM. The result was that the 3D prints of the 50x50x0.3mm shape were consistent.
As I have not been able to find the source code for this A20T machine I have not been able to enable/define the DEBUG_LEVELING_FEATURE to allow me to get more information on what is going on in the firmware.
Does anyone have any thoughts on this? Perhaps you could run the same scripts and post your results for the A20T and any other models?
I am having issues with the repeatability of the Auto Home and Bed levelling functions that are resulting in poor 3D printing.
I have designed a very thin 50x50x0.3mm square so that I can just test to see how the first layer is laid.
I have read (and seen on YouTube) elsewhere that the Start GCode needs to have G28 and G29 included for it to work so I tried that but was having variable results. Sometimes it worked OK, but sometimes the head was too low (roughening the surface) and then too high (roping effect).
I used the Repetier Host v2.1.6 to send manual and scripted commands to the A20T. I sent the M420 V command to give a verbose listing of autolevel status and the bed levelling and generated some scripts to do some experiments.
The first script was G28 and G29 repeated four times. These are the results I got:
09:46:59.144 : N17 G28*37
09:46:59.144 : N18 G29*43
09:46:59.144 : N19 G28*43
09:46:59.144 : N20 G29*32
09:46:59.144 : N21 G28*32
09:46:59.145 : N22 G29*34
09:46:59.145 : N23 G28*34
09:46:59.145 : N24 G29*36
09:48:35.921 : Bilinear Leveling Grid:
09:48:35.923 : 0 1 2
09:48:35.924 : 0 +0.188 +0.237 +0.131
09:48:35.924 : 1 +0.038 -0.010 -0.012
09:48:35.926 : 2 +0.218 +0.237 +0.221
09:50:12.637 : Bilinear Leveling Grid:
09:50:12.639 : 0 1 2
09:50:12.640 : 0 +0.149 +0.168 +0.189
09:50:12.640 : 1 +0.007 +0.029 +0.051
09:50:12.642 : 2 +0.173 +0.156 +0.239
09:51:49.476 : Bilinear Leveling Grid:
09:51:49.477 : 0 1 2
09:51:49.479 : 0 +0.406 +0.149 +0.184
09:51:49.479 : 1 +0.094 +0.124 +0.075
09:51:49.480 : 2 +0.255 +0.285 +0.281
09:53:26.309 : Bilinear Leveling Grid:
09:53:26.310 : 0 1 2
09:53:26.311 : 0 +0.098 +0.098 +0.024
09:53:26.311 : 1 -0.075 -0.104 -0.104
09:53:26.313 : 2 +0.073 +0.152 +0.108
The second script was G28 and four G29s. These are the results I got:
10:11:33.742 : N25 G28*36
10:11:33.742 : N26 G29*38
10:11:33.742 : N27 G29*39
10:11:33.742 : N28 G29*40
10:11:33.742 : N29 G29*41
10:13:10.545 : Bilinear Leveling Grid:
10:13:10.547 : 0 1 2
10:13:10.548 : 0 +0.135 +0.153 +0.106
10:13:10.548 : 1 -0.047 +0.049 -0.069
10:13:10.550 : 2 +0.131 +0.197 +0.189
10:14:30.671 : Bilinear Leveling Grid:
10:14:30.672 : 0 1 2
10:14:30.673 : 0 +0.152 +0.255 +0.153
10:14:30.673 : 1 -0.001 +0.066 -0.067
10:14:30.675 : 2 +0.103 +0.179 +0.216
10:15:50.795 : Bilinear Leveling Grid:
10:15:50.797 : 0 1 2
10:15:50.798 : 0 +0.285 +0.125 -0.060
10:15:50.798 : 1 -0.102 +0.038 +0.148
10:15:50.800 : 2 +0.163 +0.356 +0.223
10:17:10.744 : Bilinear Leveling Grid:
10:17:10.745 : 0 1 2
10:17:10.746 : 0 +0.254 +0.189 +0.059
10:17:10.746 : 1 -0.118 +0.077 -0.002
10:17:10.748 : 2 +0.049 +0.312 +0.265
Since there was no physical adjustment made to the bed levelling I would have expected the grid readings to be identical (within a small tolerance) each time - but they are not. In Script 1 the readings for 0,0 vary from +0.098 to +0.406 which is a range of 0.308. In Script 2 the readings for 0,0 vary from +0.135 to +0.285 which is a range of 0.150.
I had similar results when the printer was powered on or the reset..
I then reset the printer and did a manual 'Auto home' followed by a manual 'Bed leveling' and 'Store settings' to store the levelling results to EEPROM. My Start GCode was changed to:
G28 ; Home extruder
M420 S1; Turn on Bed Leveling and use stored results from EEPROM
M420 V ;Display Bed Leveling Status
This performed 'Auto home' and the M420 S1 used the bed levelling values stored in EEPROM. The result was that the 3D prints of the 50x50x0.3mm shape were consistent.
As I have not been able to find the source code for this A20T machine I have not been able to enable/define the DEBUG_LEVELING_FEATURE to allow me to get more information on what is going on in the firmware.
Does anyone have any thoughts on this? Perhaps you could run the same scripts and post your results for the A20T and any other models?