I recently got a used Lulzbot Mini 1 and it repeatedly fails to level the bed. It will go to touch the first washer, stop right above it, then go to wipe the nozzle. Do that a few times then it disconnects itself from my computer. I tried updating firmware and lowering the Z offset but neither works. Any advice?
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What is your Z offset now?
Are you using CuraLE 4, or some older version?
It sounds like there may be a short in the zero/ground sense wire.
In CuraLE’s terminal, send M119 as a command. You should something like this back:
If z_min is triggered and it’s not touching a washer, you’ve got a problem with the loop for detecting when it touches the corner, so the instant it tries to move down to touch the corner, it thinks it already is, and since that contact never stops, it goes to try and wipe, and after that same failure, it shuts down, since something is obviously wrong.
If M119 lists the z_min as OPEN, connect a wire between the corner washer and the nozzle, and send M119 again. If it’s still OPEN, ensure you have a good connection on the nozzle, and that it’s not obstructed by plastic, and try M119 again.
My Z offset is currently -0.7
When I ran M119 It gave me this
[10:09:00] M119
<<< [10:09:00] Reporting endstop status
<<< [10:09:00] x_min: TRIGGERED
<<< [10:09:00] x_max: open
<<< [10:09:00] y_min: open
<<< [10:09:00] y_max: open
<<< [10:09:00] z_min: open
<<< [10:09:00] z_max: open
I dont have any wire on hand so I used a paperclip, and when I touched it to the washer and nozzle it gave me the same return
Z offset with the washers should be somewhere around -1.25 with the standard (non-magnetic) bed, the washers sit on the bed, so the z offset should be the height of the washers. If your nozzle is dirty, using a -0.7 offset would be an attempt to compensate for the plastic delaying electrical connection, and lead to very inconsistent bed leveling.
But that isn’t the cause of the issue here.
Paperclips wouldn’t be a very great way to do the connection, but you can simply move the nozzle manually to (gently) contact with the washer and do an m119 again.
When I brought the nozzle into contact with the washer it gave me this
<<< [14:02:14] x_min: TRIGGERED
<<< [14:02:14] x_max: open
<<< [14:02:14] y_min: open
<<< [14:02:14] y_max: open
<<< [14:02:14] z_min: TRIGGERED
<<< [14:02:14] z_max: open
Are you able to use the manual axis movement to get the nozzle to touch, or are you having to move it by hand?
Let’s see where it thinks it is when it’s touching, use the command M114 to get the position, for example:
If you can move it through manual axis movement, it should be giving you a Z coordinate when you’re right at the washer, what is that coordinate?
If you’re having to move the nozzle down by hand to contact, how far from the washer is it and what is the reported coordinate at the lowest it will go with the manual movement controls?
Compare that with the software endstops, use M211:
If it’s just not allowing enough Z travel to find the washers, since homing Z is initially done at the top, it subtracts from that max Z and gives a minimum. One way around that is to disable the software endstops, but that could lead to damage if plastic is on the nozzle and prevents electrical contact long enough that there is damage to the nozzle or printbed. G92 adjusts the software endstops, so you can use it to fool it to go lower, either. That leaves the option to just trigger the Z max switches a few millimeters sooner.
If your wipe and probe sequence attempt is similar to SoCalRedneck’s here: https://youtu.be/W8EC_yOBRls?t=110
then the nozzle isn’t getting low enough to wipe either, so if you put some spacers just slightly taller than the height the nozzle stops at when trying to probe, it should correct both issues. I’m not sure if the firmware had the limits changed, or if they changed an X gantry part that caused the switches to be hit too late when using the old part.
I know we are working on a z_min issue so I hate to state the obvious, x_min: TRIGGERED doesn’t seem right.
I just assumed the toolhead was starting from the Xmin, since he didn’t mention issues with the wipe.
Its exactly like the video you sent, should I use some standard washers stacked on top of the original ones to fix the issue?
I think that the first bed leveling spot is at x min, so it should be triggered
Ok, see the response to that post about using spacers to artificially lower the Z maximum trigger spot, or disabling the software endstops prior to wipe/probe.
The X min triggered might actually be an issue.
If the move down is a simultaneous X and Z move, and it starts the move with the X axis not already against the X_min switch, and it hits the X_min switch before it finishes the Z downward movement, it will probably abort the rest of the Z movement, leaving the nozzle higher than intended. It’s a bit of a stretch, but it would be worth checking if this is happening.
We saw a similar issue on the Workhorse a while back. When you started an auto-calibration, it would do a simultaneous X and Y move toward the calibration cube. To reach the center of the cube it has to go right to Y_min, but due to a fraction of a millimeter of variance on when the switch actually clicks, sometimes the Y_min switch would click early and abort the rest of the X/Y move, leaving the X axis short of reaching the cube. Then it would move down like it was probing the cube, but miss the cube a few centimeters to the left. I fixed it by separating the X and Y moves, so that it wouldn’t matter if it bumped the Y-Min switch.
Something similar could be happening here.