A20T Auto Levelling Issues

[aplcomms]

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?

[sednomen]

Hello, I have started today with this same printer, also with 3DTouch and updated. I have observed the same as you, sometimes the head is too low and sometimes too high, as if it was not really calculating correctly. I have done the test of placing the object in different parts of the bed, intentionally a little uneven, and I understand that with autolevel it should calculate correctly and print, but it is not. I think it is a bug. With the printer I had before it worked correctly and with the A10T it also worked for me.
If I print an object without using the G29 it prints more or less well.

I'm going to do the same tests as you and I tell you.
The GCODE I managed to run on the A10T was this (is very important no G28 AFTER G29)

G28
G1 Z15 F300
M107
G90
M82
G28 X0
G28 Y0
G29
G1 X0 Y0 F2400
M104 S200
M140 S55
G92 E0
M109 S200
M107
M163 S0 P1
M163 S1 P0
M163 S2 P0
M164 S4
G1 E10
G0 X10 Y20 F6000
G1 Z0.8 ; This is for clean nozzle before print. An horizontal line not so near bed.
G1 F300 X200 E40
G1 F1200 Z0
G92 E0

[sednomen]

My code results:
23:26:20.169 : N17 G28*37
23:26:28.801 : N18 G29*43
23:26:40.430 : N19 M420 V*107
23:26:44.032 : Bilinear Leveling Grid:
23:26:44.033 : 0 1 2
23:26:44.035 : 0 +0.032 +0.061 -0.015
23:26:44.035 : 1 -0.119 -0.100 -0.176
23:26:44.036 : 2 -0.043 -0.026 -0.189
23:26:44.041 : X:237.00 Y:244.00 Z:12.67 E:0.00 Count X:19031 Y:19715 Z:4992
23:27:01.765 : X:162.00 Y:125.00 Z:12.48 E:0.00 Count X:13009 Y:10100 Z:4992
23:27:01.803 : N20 G29*32
23:27:23.266 : N21 M420 V*96
23:28:20.851 : Bilinear Leveling Grid:
23:28:20.853 : 0 1 2
23:28:20.854 : 0 +0.051 +0.111 +0.080
23:28:20.854 : 1 -0.029 +0.020 -0.093
23:28:20.856 : 2 +0.014 +0.009 -0.142
23:28:20.860 : X:237.00 Y:244.00 Z:12.62 E:0.00 Count X:19031 Y:19715 Z:4992
23:28:38.684 : X:162.00 Y:125.00 Z:12.48 E:0.00 Count X:13009 Y:10100 Z:4992
23:29:07.963 : N22 G29*34
23:29:14.015 : N23 M420 V*98
23:29:57.707 : Bilinear Leveling Grid:
23:29:57.708 : 0 1 2
23:29:57.709 : 0 +0.141 +0.204 +0.112
23:29:57.709 : 1 +0.003 +0.068 -0.046
23:29:57.711 : 2 +0.086 +0.069 -0.046
23:29:57.715 : X:237.00 Y:244.00 Z:12.53 E:0.00 Count X:19031 Y:19715 Z:4992
23:30:15.412 : X:162.00 Y:125.00 Z:12.48 E:0.00 Count X:13009 Y:10100 Z:4992
23:30:54.632 : N24 G29*36
23:31:00.085 : N25 M420 V*100
23:31:34.507 : Bilinear Leveling Grid:
23:31:34.508 : 0 1 2
23:31:34.510 : 0 +0.085 +0.084 +0.055
23:31:34.510 : 1 -0.031 +0.008 -0.088
23:31:34.511 : 2 -0.021 +0.058 -0.168
23:31:34.514 : X:237.00 Y:244.00 Z:12.65 E:0.00 Count X:19031 Y:19715 Z:4992
23:31:34.516 : Bilinear Leveling Grid:
23:31:34.518 : 0 1 2
23:31:34.518 : 0 +0.085 +0.084 +0.055
23:31:34.519 : 1 -0.031 +0.008 -0.088
23:31:34.521 : 2 -0.021 +0.058 -0.168
23:31:34.523 : echo:Bed Leveling On
23:31:34.523 : echo:Fade Height 10.00
23:32:54.584 : Bilinear Leveling Grid:
23:32:54.585 : 0 1 2
23:32:54.587 : 0 +0.210 +0.283 +0.217
23:32:54.587 : 1 +0.197 +0.170 +0.096
23:32:54.588 : 2 +0.253 +0.244 +0.057
23:32:54.591 : X:237.00 Y:244.00 Z:12.42 E:0.00 Count X:19031 Y:19715 Z:4992
23:32:54.593 : Bilinear Leveling Grid:
23:32:54.594 : 0 1 2
23:32:54.594 : 0 +0.210 +0.283 +0.217
23:32:54.596 : 1 +0.197 +0.170 +0.096
23:32:54.597 : 2 +0.253 +0.244 +0.057
23:32:54.599 : echo:Bed Leveling On
23:32:54.600 : echo:Fade Height 10.00

[Square2k1]

How Did you guys get on ?

i have an issue also that after the G29 the printer doesnt go through the bed test test and then starts to extruder before the nozle is to temp


it would be nice for Geeetech to give us a working starting code.

[sneazzy95]

I thought I was the one having this issue with the G29.

[adrianh]

Hi,
I have read your posts with interest. I am a complete numpty where coding is concerned and bought my A10M (End of September 2019) thinking it would work "Out of the box" with the firmware was supplied. My machine appears to be doing the same inconsistent leveling even without the 3d/BL Touch sensors on a very well leveled bed. Printing is either too high or gouges the bed surface seemingly at random with each print, with the occasional half decent print thrown in. Geeetech Tech support keep telling me to use the original firmware supplied (1.1.8) and level the bed as per their videos. They seem to be oblivious to the issues which seems to be endemic across their range of machines. I bought an Ender 3 Pro to get me by with some work I had planned and it has hardly missed a print in 4 months and several hundred prints.

[Square2k1]

Guys with some help of the facebook the solution to get it to probe the bed is as follows:


after the: G28; move to the next line
then enter: G29; move to the next nine
then enter: M420 V;

so it looks like this

G28;
G29;
M420 V;

and then the rest of your code.

Enjoy