Printer Head Slamming Into Bed During AutoHome

I have a Lulzbot Taz 6 with single head extruder. I’m having a problem where, when I go to auto home, it drops the head down to the bed and then slams into the bed. It won’t stop doing it until I turn the machine off. The firmware is up to date and I can’t figure out what’s going on. Any ideas?

Interesting… does this happen when you manually home the Z? Or only during a print?

If during a print, make sure there isn’t a Z-offset set in the slicer. Or an offset set by accident through gcode. A M501 should show you the current eeprom settings.

Thanks for the response!
Interestingly, the Z Offset was set to -1.2. I tried setting it to 0 and then using auto home, but still had the same issue. This is all done through the Graphical LCD Controller. I don’t even have a computer plugged in.

Hello alexandreamel,

It sounds like you have TAZ5 firmware loaded on that TAZ6. Be sure you have the 6 firmware loaded and give that another try.

If that doesn’t get you back up and running then reach out to our support at 24/7


This happened to me when I first started using my Taz 6. It printed one clean print and then started to grind the head into the bed for all others after…

What worked for me was to watch the auto-level sequence very carefully - I’ll explain.

Before printing, I pre-heat up the head to 230 and the bed to 50. Once the head is up to temperature I manually wind the filament out by 1cm and then clean it using a scouring pad as recommended by the Lulzbot support team (non conductive). After I am sure the head is clean, I start the print (normally from SD card). I’m always watching for extrusion and I remove any using the tweezers supplied in the kit bag. The first thing the printer does is start the auto bed level sequence and clean the head on the bed pad on the left. It then moves the head to the front left bed securing washer and slowly lowers the head until it touches. THIS IS THE CRITICAL PART. If there is ANY bending of the bed (i.e. the head pushes the corner of the bed down by any amount) then I abort the print and then start my cleaning sequence again. The head should light-touch the washer and no more. Remember if you do abort and restart the print then the filament is retracted by a further amount just before the bed level sequence starts so you need to push some back in again or when your print does eventually start, it will take a while to put plastic down.

The auto bed leveling is done by checking an electrical contact between the head and the bed washer. I use Inova1800 which is quite sticky and this seems to make the head dirty and non conductive all the time. I have to do this for EVERY print.

I have also increased the nozzle cleaning temperature to 200 in the profile on Cura so when it auto cleans the head, it does so at a higher temperature. I think this helps.

I always add a bigger brim or skirt than normal so I can adjust the Z level and clear up any debris as the nozzle starts to print.

One last thing I want to try and will do soon is to change the nozzle cleaning sequence to a faster more vigorous full length sequence so the nozzle has a better chance of being cleaned by the built-in cleaner. That might save me using the scouring pad so much.

You also may need to check the level of the left and right z axis thread winders as they may be out of alignment. Move the Z to the top and then measure the distance to the top frame bars. Manually wind the right Z motor until the both the left and right are the same height. Do this while powered off or the motors might be locked.

I wish someone had told me this when I first started to print :slight_smile: