‎Lulzbot Taz 6 wiping nozzle over z-min switch

Hello. I got a Lulzbot Taz 6 that didn’t work and I’ve been trying to fix. I have a Taz 6 with a dual extruder v2 head on it. When I tried to print some gcode using Cura for lulzbot version 3.6.37 it was always failing to probe the bed. It would try to wipe the nozzles and the print head would go too low into the wiping pad and scraping the edges of the pad holder, then when it goes to probe the print head it would fail as the nozzle would touch the bed and not the bed leveling washers.

I then tried updating the firmware using Cura to TAZ 6 dualextruderV2 and now when I try printing, the printer tries to wipe the nozzle where the z-min switch is, and not where the wiping pad is. I tried flashing an older firmware from the lulzbot website and still the same problem. Even tried the firmware, same problem. The nozzle wipes over the z-min switch and not the wiping pad, and then I get bed leveling failed.

Anyone know how to fix this?

Please post a picture of the tool head. Do you have any other tool heads? Hopefully, you have the Single Extruder V2.1 that was the standard tool head shipped with the printer. If you have it, have you successfully printed with it?

The Dual Extruder V2 has the two nozzles back to back (second nozzle offset in Y by -50 mm). The Dual Extruder V3 has the two nozzles side by side (second nozzle offset in X by 13mm).

I have both dual extruders for my TAZ 6 but my V2 is boxed up. I don’t remember what firmware version worked with it. I’ll get it out and see if I can make it work once we verify that everything else is working on your TAZ 6.

Can you also slice something simple like a 5x5x5mm cube and post the gcode produced? Maybe slice two of them side by side in two different colors.

Hi. Here are some photos of the tool head

I got the printer from school cause it wasn’t working and they were going to throw it out. I was going to see if I could fix it up and keep it for personal use. I’ll ask if they have the original tool head laying somewhere and if they do I’ll use that because I really don’t care about dual extrusion. I only want to do single extrusion with this dualextruderV2 tool head, and don’t want to spend $300+ for a new single extruder when I’m not even sure if I can get this printer to work properly.

Here is the G-Code for a simple square

;Generated by Cura LulzBot Edition GCodeWriter Version: 3.6.37
;Filament used: 0.0114215m, 0m
;Layer height: 0.265
;Generated with Cura_SteamEngine 3.6.37-win10
M82 ;absolute extrusion mode
;This profile is designed specifically for LulzBot TAZ6 3D Printer with Dual Extruder V2 Tool Head
M75 ; start GLCD timer
G26 ; clear potential ‘probe fail’ condition
M107 ; disable fans
M420 S0 ; disable leveling matrix
G90 ; absolute positioning
T0 ; select this extruder first
M82 ; set extruder to absolute mode
G92 E0 ; set extruder position to 0
M140 S67.5 ; get bed heating up
M104 R170 T1 ; soften filament
M109 R140 T0 ; soften filament
M109 R170 T1 ; soften filament
G28 X Y ; home X and Y
G1 X-19 Y258 ; move over the Z_MIN switch
M104 R170 T1 ; wait for T1 to reach temp
M109 R140 T0 ; wait for T0 to reach temp
M109 R170 T1 ; wait for T1 to reach temp
G28 Z ; home Z
G1 E-15 F100 ; suck up XXmm of filament
T1 ; switch extruders
M82 ; set extruder to absolute mode
G92 E0 ; set E to 0
G1 E-15 F100 ; suck up filament
T0 ; switch extruders
;G92 E-60 ; adjust E value
G1 X-17 Y100 F3000 ; move above wiper pad
G1 Z1 ; push nozzle into wiper
G1 X-19 Y95 F1000 ; slow wipe
G1 X-17 Y90 F1000 ; slow wipe
G1 X-19 Y85 F1000 ; slow wipe
G1 X-17 Y90 F1000 ; slow wipe
G1 X-19 Y80 F1000 ; slow wipe
G1 X-17 Y95 F1000 ; slow wipe
G1 X-19 Y75 F2000 ; fast wipe
G1 X-17 Y85 F2000 ; fast wipe
G1 X-19 Y80 F2000 ; fast wipe
G1 X-17 Y70 F2000 ; fast wipe
G1 X-19 Y75 F2000 ; fast wipe
G1 X-17 Y95 F1000 ; slow wipe
G1 X-19 Y90 F1000 ; slow wipe
G1 X-17 Y85 F1000 ; slow wipe
G1 X-19 Y90 F1000 ; slow wipe
G1 X-17 Y80 F1000 ; slow wipe
G1 X-19 Y95 F1000 ; slow wipe
G1 X-17 Y75 F2000 ; fast wipe
G1 X-19 Y85 F2000 ; fast wipe
G1 X-17 Y80 F2000 ; fast wipe
G1 X-19 Y90 F2000 ; fast wipe
G1 X-17 Y85 F2000 ; fast wipe
G1 Z10 ; raise extruder
M109 R140 ; heat to probe temp
G1 X-9 Y-9 ; move above first probe point
M204 S100 ; set accel for probing
G29 ; probe sequence (for auto-leveling)
M420 S1 ; enable leveling matrix
M425 Z ; use measured Z backlash for compensation
M425 Z F0 ; turn off measured Z backlash compensation. (if activated in the quality settings, this command will automatically be ignored)
M204 S500 ; set accel back to normal
G1 X0 Y0 Z15 F5000 ; get out the way
M400 ; clear buffer
M140 S67.5; get bed heating up
M104 S250 T1; set extruder temp
M109 R210 T0 ; set extruder temp and wait
M109 R250 T1; set extruder temp and wait
T1 ; switch to second extruder
G1 E0 F100 ; prime nozzle from previous print
G1 F100 E-1.75 ;retract second nozzle before print
G92 E-30 ; adjust to 1st nozzle e value
T0 ; switch back to back
M190 R67.5; get bed temping up during first layer
G1 Z2 E0 F75 ; extrude filament back into nozzle
M117 TAZ Printing… ; LCD status message

M221 S100 T0
M221 S100 T1
G92 E0
G1 F600 E-1.75
G0 F2625 X130.628 Y130.672 Z0.25
G1 F600 E0
G1 F900 X131.088 Y130.263 E0.01206
G1 X131.598 Y129.916 E0.02415
G1 X132.148 Y129.639 E0.03621
G1 X132.729 Y129.435 E0.04828
G1 X133.332 Y129.307 E0.06036
G1 X134.009 Y129.259 E0.07366
G1 X145.991 Y129.26 E0.30844
G1 X146.606 Y129.3 E0.32051
G1 X147.211 Y129.419 E0.33259
G1 X147.795 Y129.616 E0.34467
G1 X148.348 Y129.886 E0.35673
G1 X148.862 Y130.226 E0.3688
G1 X149.328 Y130.629 E0.38088
G1 X149.737 Y131.09 E0.39295
G1 X150.084 Y131.599 E0.40502
G1 X150.361 Y132.149 E0.41709
G1 X150.565 Y132.731 E0.42917
G1 X150.693 Y133.333 E0.44123
G1 X150.741 Y134.01 E0.45453
G1 X150.741 Y145.991 E0.68929
G1 X150.701 Y146.606 E0.70137
G1 X150.582 Y147.21 E0.71343
G1 X150.385 Y147.794 E0.72551
G1 X150.115 Y148.348 E0.73758
G1 X149.775 Y148.862 E0.74966
G1 X149.372 Y149.328 E0.76173
G1 X148.912 Y149.737 E0.77379
G1 X148.402 Y150.084 E0.78588
G1 X147.852 Y150.361 E0.79794
G1 X147.271 Y150.565 E0.81001
G1 X146.668 Y150.693 E0.82209
G1 X145.991 Y150.741 E0.83539
G1 X134.009 Y150.741 E1.07017
G1 X133.394 Y150.701 E1.08224
G1 X132.79 Y150.582 E1.0943
G1 X132.206 Y150.385 E1.10638
G1 X131.652 Y150.115 E1.11846
G1 X131.138 Y149.775 E1.13053
G1 X130.672 Y149.372 E1.1426
G1 X130.263 Y148.912 E1.15467
G1 X129.916 Y148.402 E1.16675
G1 X129.639 Y147.852 E1.17882
G1 X129.435 Y147.271 E1.19088
G1 X129.307 Y146.668 E1.20296
G1 X129.259 Y145.991 E1.21626
G1 X129.259 Y134.009 E1.45104
G1 X129.299 Y133.394 E1.46312
G1 X129.418 Y132.79 E1.47518
G1 X129.615 Y132.206 E1.48726
G1 X129.885 Y131.652 E1.49933
G1 X130.225 Y131.138 E1.51141
G1 X130.628 Y130.672 E1.52348
G0 F2625 X131.12 Y130.892
G1 F900 X131.574 Y130.526 E1.53491
G1 X132.073 Y130.226 E1.54631
G1 X132.609 Y129.996 E1.55774
G1 X133.171 Y129.842 E1.56916
G1 X134.009 Y129.759 E1.58566
G1 X145.991 Y129.76 E1.82044
G1 X146.573 Y129.8 E1.83187
G1 X147.143 Y129.919 E1.84328
G1 X147.692 Y130.115 E1.8547
G1 X148.209 Y130.385 E1.86613
G1 X148.684 Y130.722 E1.87754
G1 X149.108 Y131.121 E1.88895
G1 X149.474 Y131.575 E1.90038
G1 X149.775 Y132.074 E1.9118
G1 X150.004 Y132.61 E1.92322
G1 X150.158 Y133.172 E1.93464
G1 X150.241 Y134.01 E1.95114
G1 X150.241 Y145.991 E2.1859
G1 X150.201 Y146.572 E2.19731
G1 X150.082 Y147.143 E2.20874
G1 X149.886 Y147.692 E2.22016
G1 X149.617 Y148.208 E2.23156
G1 X149.279 Y148.684 E2.243
G1 X148.88 Y149.108 E2.25441
G1 X148.426 Y149.474 E2.26583
G1 X147.927 Y149.774 E2.27724
G1 X147.391 Y150.004 E2.28867
G1 X146.829 Y150.158 E2.30009
G1 X145.991 Y150.241 E2.31659
G1 X134.009 Y150.241 E2.55137
G1 X133.428 Y150.201 E2.56278
G1 X132.857 Y150.082 E2.57421
G1 X132.308 Y149.886 E2.58563
G1 X131.792 Y149.617 E2.59703
G1 X131.316 Y149.279 E2.60847
G1 X130.892 Y148.88 E2.61988
G1 X130.526 Y148.426 E2.63131
G1 X130.226 Y147.927 E2.64272
G1 X129.996 Y147.391 E2.65414
G1 X129.842 Y146.829 E2.66556
G1 X129.759 Y145.991 E2.68206
G1 X129.759 Y134.009 E2.91684
G1 X129.799 Y133.428 E2.92825
G1 X129.918 Y132.857 E2.93968
G1 X130.114 Y132.308 E2.9511
G1 X130.383 Y131.792 E2.96251
G1 X130.721 Y131.316 E2.97395
G1 X131.12 Y130.892 E2.98535
G0 F2625 X131.216 Y131.507
G1 F900 X131.61 Y131.127 E2.99608
G1 X132.055 Y130.808 E3.00681
G1 X132.542 Y130.558 E3.01753
G1 X133.06 Y130.381 E3.02826
G1 X133.598 Y130.282 E3.03898
G1 X134.009 Y130.259 E3.04704
G1 X145.991 Y130.26 E3.28182
G1 X146.537 Y130.3 E3.29255
G1 X147.071 Y130.419 E3.30327
G1 X147.583 Y130.615 E3.31401
G1 X148.06 Y130.882 E3.32472
G1 X148.493 Y131.217 E3.33545
G1 X148.873 Y131.611 E3.34618
G1 X149.192 Y132.056 E3.35691
G1 X149.442 Y132.543 E3.36763
G1 X149.619 Y133.061 E3.37836
G1 X149.718 Y133.599 E3.38908
G1 X149.741 Y134.01 E3.39714
G1 X149.741 Y145.991 E3.6319
G1 X149.701 Y146.537 E3.64263
G1 X149.582 Y147.071 E3.65335
G1 X149.387 Y147.582 E3.66407
G1 X149.119 Y148.06 E3.6748
G1 X148.784 Y148.493 E3.68553
G1 X148.39 Y148.873 E3.69626
G1 X147.945 Y149.192 E3.70699
G1 X147.458 Y149.442 E3.71771
G1 X146.94 Y149.619 E3.72844
G1 X146.402 Y149.718 E3.73916
G1 X145.991 Y149.741 E3.74722
G1 X134.009 Y149.741 E3.982
G1 X133.463 Y149.701 E3.99273
G1 X132.929 Y149.582 E4.00345
G1 X132.418 Y149.387 E4.01417
G1 X131.94 Y149.119 E4.0249
G1 X131.507 Y148.784 E4.03563
G1 X131.127 Y148.39 E4.04636
G1 X130.808 Y147.945 E4.05709
G1 X130.558 Y147.458 E4.06781
G1 X130.381 Y146.94 E4.07854
G1 X130.282 Y146.402 E4.08926
G1 X130.259 Y145.991 E4.09732
G1 X130.259 Y134.009 E4.3321
G1 X130.299 Y133.463 E4.34283
G1 X130.418 Y132.929 E4.35355
G1 X130.613 Y132.418 E4.36427
G1 X130.881 Y131.94 E4.375
G1 X131.216 Y131.507 E4.38573
G0 F2625 X131.709 Y131.713
G1 F900 X132.096 Y131.381 E4.39572
G1 X132.531 Y131.115 E4.40571
G1 X133.001 Y130.919 E4.41569
G1 X133.496 Y130.8 E4.42567
G1 X134.009 Y130.759 E4.43575
G1 X145.991 Y130.76 E4.67053
G1 X146.499 Y130.8 E4.68051
G1 X146.995 Y130.919 E4.69051
G1 X147.465 Y131.114 E4.70048
G1 X147.9 Y131.38 E4.71047
G1 X148.288 Y131.71 E4.72045
G1 X148.619 Y132.098 E4.73044
G1 X148.885 Y132.532 E4.74042
G1 X149.081 Y133.002 E4.7504
G1 X149.2 Y133.498 E4.76039
G1 X149.241 Y134.01 E4.77045
G1 X149.241 Y145.991 E5.00521
G1 X149.201 Y146.499 E5.0152
G1 X149.082 Y146.994 E5.02517
G1 X148.887 Y147.465 E5.03516
G1 X148.621 Y147.9 E5.04515
G1 X148.291 Y148.287 E5.05512
G1 X147.904 Y148.619 E5.06511
G1 X147.469 Y148.885 E5.0751
G1 X146.999 Y149.081 E5.08508
G1 X146.504 Y149.2 E5.09506
G1 X145.991 Y149.241 E5.10514
G1 X134.009 Y149.241 E5.33992
G1 X133.501 Y149.201 E5.3499
G1 X133.006 Y149.082 E5.35988
G1 X132.535 Y148.887 E5.36987
G1 X132.1 Y148.621 E5.37986
G1 X131.713 Y148.291 E5.38982
G1 X131.381 Y147.904 E5.39981
G1 X131.115 Y147.469 E5.40981
G1 X130.919 Y146.999 E5.41978
G1 X130.8 Y146.504 E5.42976
G1 X130.759 Y145.991 E5.43984
G1 X130.759 Y134.009 E5.67462
G1 X130.799 Y133.501 E5.68461
G1 X130.918 Y133.006 E5.69458
G1 X131.113 Y132.535 E5.70457
G1 X131.379 Y132.1 E5.71456
G1 X131.709 Y131.713 E5.72453
G1 F600 E3.97453
G0 F2625 X134.514 Y133.335
G0 X134.514 Y134.514
G0 X134.982 Y145.018
G0 X145.25 Y145.25
G1 F600 E5.72453
G1 F900 X134.75 Y145.25 E5.93027
G1 X134.75 Y134.75 E6.13601
G1 X145.25 Y134.75 E6.34175
G1 X145.25 Y145.25 E6.54749
G0 F2625 X145.75 Y145.75
G1 F900 X134.25 Y145.75 E6.77282
G1 X134.25 Y134.25 E6.99816
G1 X145.75 Y134.25 E7.22349
G1 X145.75 Y145.75 E7.44883
G0 F2625 X145.5 Y145.75
G0 X145.43 Y145.43
G0 X145.09 Y144.76
G0 X144.76 Y144.76
G1 F900 X135.24 Y144.76 E7.63537
G1 X135.24 Y135.24 E7.8219
G1 X144.76 Y135.24 E8.00844
G1 X144.76 Y144.76 E8.19498
G0 F2625 X145.09 Y144.76
G0 X145.09 Y136.049
G0 X144.534 Y136.049
G1 F900 X143.949 Y135.464 E8.21119
G0 F2625 X143.242 Y135.464
G1 F900 X144.534 Y136.756 E8.24699
G0 F2625 X144.534 Y137.463
G1 F900 X142.535 Y135.464 E8.30239
G0 F2625 X141.828 Y135.464
G1 F900 X144.534 Y138.17 E8.37737
G0 F2625 X144.534 Y138.877
G1 F900 X141.121 Y135.464 E8.47195
G0 F2625 X140.414 Y135.464
G1 F900 X144.534 Y139.584 E8.58612
G0 F2625 X144.534 Y140.292
G1 F900 X139.707 Y135.464 E8.71989
G0 F2625 X139 Y135.464
G1 F900 X144.534 Y140.999 E8.87325
G0 F2625 X144.534 Y141.706
G1 F900 X138.293 Y135.464 E9.04621
G0 F2625 X137.586 Y135.464
G1 F900 X144.534 Y142.413 E9.23875
G0 F2625 X144.534 Y143.12
G1 F900 X136.878 Y135.464 E9.45091
G0 F2625 X136.171 Y135.464
G1 F900 X144.534 Y143.827 E9.68265
G0 F2625 X144.534 Y144.534
G1 F900 X135.464 Y135.464 E9.93398
G0 F2625 X135.464 Y136.171
G1 F900 X143.826 Y144.534 E10.16571
G0 F2625 X143.119 Y144.534
G1 F900 X135.464 Y136.878 E10.37785
G0 F2625 X135.464 Y137.586
G1 F900 X142.412 Y144.534 E10.57039
G0 F2625 X141.705 Y144.534
G1 F900 X135.464 Y138.293 E10.74333
G0 F2625 X135.464 Y139
G1 F900 X140.998 Y144.534 E10.89668
G0 F2625 X140.291 Y144.534
G1 F900 X135.464 Y139.707 E11.03044
G0 F2625 X135.464 Y140.414
G1 F900 X139.584 Y144.534 E11.1446
G0 F2625 X138.877 Y144.534
G1 F900 X135.464 Y141.121 E11.23918
G0 F2625 X135.464 Y141.828
G1 F900 X138.17 Y144.534 E11.31417
G0 F2625 X137.462 Y144.534
G1 F900 X135.464 Y142.535 E11.36954
G0 F2625 X135.464 Y143.242
G1 F900 X136.755 Y144.534 E11.40533
G0 F2625 X136.048 Y144.534
G1 F900 X135.464 Y143.949 E11.42153
G0 F2625 X135 Y143.949
G1 F600 E9.67153
M140 S0
M104 S0 T0 ; T0 hotend off
M104 S0 T1 ; T1 hotend off
M107 ; fans off
G91 ; relative positioning
G1 E-1 F300 ; retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z20 E-5 X-20 Y-20 F3000 ; move Z up a bit and retract filament even more
G1 E6 ; re-prime extruder 1
G1 E-5 F300 ; retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 E5 ; re-prime extruder 2
M117 Cooling please wait ; progress indicator message
G90 ; absolute positioning
G1 Y0 F3000 ; move to cooling position
M190 R47.5 ; set bed to cool off
G1 Y280 F3000 ; present finished print
M140 S47.5; keep temperature or cool downs
M77 ; stop GLCD timer
M84 ; steppers off
G90 ; absolute positioning
M117 Print complete ; progress indicator message

M82 ;absolute extrusion mode
;End of Gcode

It does look like from your pictures that there is an adapter plate over the Z-min switch. Am I right?


Hi. Yes I do have that adapter on. I removed the adapter but still get the same problem. It wipes the nozzles over the z-min switch area and ends the print with probing failed.

Here’s a video of what’s happening.

I got my Dual Extruder V2 out of its box but after installing it I noticed that the cold end cooling fan on E0 (back extruder) has a broken mount so the fan is just hanging loose.

I did update the firmware to and was able manually to do a G28 XY and a G28 Z with the Z-Min adapter in place. I then manually moved the tool head with G0 X50 Y50 and lowered Z via the LCD control panel 1mm at a time until I got to 0. At this point, the nozzle was around 5-10mm above the bed so I believe the adapter isn’t used on the Dual Extruder V2 so I removed it and tried again. This time I got to Z2.0 and the nozzles are almost touching the bed so further investigation would be required.

The next experiment is to manually move Z to a save 10mm (G0 Z10) and then manually move the tool head to the first position of the wipe sequence G1 X-17 Y100 F3000 ; move above wiper pad. The back nozzle is just inside the back of the pad and is centered on the pad. Next, G1 X-17 Y70 F2000 ; fast wipe which is the minimum Y value in the wipe sequence. The front nozzle (E1) is near the front of the pad but still over it.

I can’t do a G29 V4 because of the loose fan. I’ll try to glue it in place with some silicone and try again after that dries.

Try these commands on your system and see where things go wrong.

If you do get the V2 to work, the cold end fans were barely adequate. Here’s a pointer to an upgrade that I’d consider if I still used the V2.

Also, here’s a Single Extruder on eBay with a .35mm nozzle (which could easily be changed back to a stock .5mm). Make an offer!

When I initially got the printer the extruder would only move in the -x direction and not the +x direction. This was because there’s no limit switch for the +x side so the printer thought the switch was being pressed at all times. I took out the pins from the connector and shorted them together and the printer would now work in the +x direction, but on the old firmware. Since updating the printer it seems like that part was fixed in the firmware and having the two pins shorted makes the printer now think the limit switch is pressed. I disconnected the short between the pins and now it’s wiping in the correct location again.

Printer location and bed leveling is working now.

When I run a print the first layer is nothing, it looks like the nozzle is hitting the bed and not letting material come out. I’m assuming this has to do with the probe z offset setting. I’ll play around with it and see what I can find.

Thank you very much for your time and assistance in troubleshooting my problem.