I am trying to update my firmware to slow down the beveling when it start the process ( the nozzle presses the bed down about and 1/8" before completing the second touch which i believe is giving a false leveling matrix which will not repeat at the Z offset from print to print. we just upgraded from the Taz 6 to the Workhorse and Pro. the Taz 6 did not have this issue. Support led me to a trail change but when I try to compile, Marlin errors out at src files which were not changed.
I own both a TAZ Workhorse & Pro. I’ve had these issues myself.
What has helped:
- Most of the time it was a dirty nozzle. BTW, a “dirty” nozzle can actually appear to be “clean”. You can get a build-up on the nozzle and it only needs to be micro-thin to create resistance.
One difference between your TAZ 6 vs. the TAZ Workhorse and Pro are that the Workhorse and Pro use “hardened steel” nozzles. Your TAZ 6 used a beryllium copper nozzle (much more conductive). (You’ll also likely find the hardened steel nozzle doesn’t transfer heat as efficiently and you may need to print around 5°C (maybe 10°C) hotter than you did on your TAZ 6.)
I have a small brass wire brush (roughly the size of a toothbrush) and I use that to gently scrub the nozzles clean. This gets rid of any build-up on the nozzle (think of this like the “seasoning” that builds up on cast-iron frying pans). BE CAREFUL. If the printer is powered on when you do this, there are wires connected to the hot-end and you can cause sparks (ask me how I know ). So I’m very careful to either do this with the printer powered off or run the wire brush straight front to back and back to front … not side-to-side where there’s chance of hitting those wires.
- The OTHER problem I had with bed leveling… was a loose washer. I had an issue with my Workhorse where the bed-leveling would (not always… but often) have a problem on the right-rear corner … far more than any other corner. I pulled out the allen-key set to check it and, sure enough, that particular corner was barely snug. These washers are holding down a glass plate so you don’t want to reef on them … but they should be gently snugged (mine was a bit loose). So if you are getting persistent failures in a specific corner, check the washer to make sure it isn’t loose.
I have read about stories where the nozzle didn’t have a good connection … but the Workhorse and Pro haven’t been out that long so that’s probably not the case for your printers. The idea was that after years of age, the dissimilar metals in the nozzle vs. the hot-end can have a metallurgical reaction that reduces conductivity. But you can test this with an ohm-meter (multi-meter). You can think of each component as a link in a conductive “chain”. Washer to bed, bed to wire harness, wire harness to control board, etc. But on the print head it’s… extruder nozzle to hot-end, hot-end to cold-end, there’s typically a wire on one of the screws on the heat-sink fan and THAT’s the wire that connects back to the wire harness and ultimately to the board. You can check the ohms between each component and trace your way back until you find any weak connections. As I ohm-out each connection I’m used to seeing resistance of around 1Ω … when I had the loose washer I would sometimes get 1Ω … but I also sometimes got around 10Ω or 25Ω … and that’s too much.
As I said, it’s usually a dirty nozzle that didn’t make strong electrical contact and not anything to do with wiring … but it’s pretty easy to test it.
Ever since I used the brass wire brush (brass because it’s a soft metal) … I’ve never had another bed-leveling failure. Just be careful not to touch those wires with the brash brush.
The leveling process hasn’t given me problems, the machines will level but the reputability of the starting height is the issue. The machines with start a couple of times using the same Z offset then the next print will start way to high then on a restart of the same file the nozzle will be to low. I want to slow down the first touch of the leveling sequence because the nozzle conductivity isn’t communicating fast enough for the process(nozzle material less conductive as you have stated). Our Taz6 had an aeroextruder with a hardened nozzle which worked fine but didn’t try to go as fast during leveling especially the first touch.
I have found my answer, I was able adjust firmware setting ( a little confusing with very little documentation from Lulzbot- workhorse setting are labeled as experimental) finally which works wonderfully for the consistent repeatability from print to print and same Z offset. Thank you for the input so far same printing performance reliability as our Taz 6.
During leveling process the bed does not flex an 1/8" upon first touch ( maybe .020" on very first washer) and no movement during second touch-very reliable so far. TheVirtualTim thank you for your comments and information, dirty nozzle was my first item but slowing down the first touch in the level process really allow the machine to communicate more consistently. Thank you again for your efforta and time.