Strange z offset after printing.

dc42

I can't see anything obviously wrong with your files. Two possibilities:

This issue might be related to the one that I fixed in firmware 2.0, even though that one was most evident when using mesh bed compensation. So you could try upgrading to firmware 2.0.
If the print file is somehow changing the babystepping amount or the tool Z offset, that would cause the problem. So try sending the following commands after a print and check that the results returned are correct:

G31 T5 ; should return trigger height = 2.0
M290 ; should return zero, or whatever babystepping you used
G10 P0 ; should return Z offset = 0

lolmodule

Ok. I re did my Z0 and my probe trigger height just to make sure everything was ok. Which is why my trigger height is a tad different than before. I printed a calibration cube and put in the commands you suggested @dc42 this is the results:

G10 P0
Tool 0 offsets: X0.00 Y0.00 Z0.00, active/standby temperature(s): 0.0/0.0

M290
Baby stepping offset is 0.000mm

G31 T5
Threshold 500, trigger height 2.19, offsets X0.0 Y-40.0

Everything looks good right?

https://gyazo.com/e708fbecbdc5baf48ebf945f10f2fadf

Notice the commanded position and the readout in the top right.

I tried the suggestion by @Phaedrux and manually entered that move command ( verified Z 0, sent the G1 Z+10.00 F20000, then back to 0 and it was fine.)

I have no idea whats going on. I haven't updated to 2.0 yet but I think it might fix whatever issue I might be having but I will wait to see what you all have to say.

I really do appreciate the time you guys ( even though it may not be much time) put into helping me out.

dc42

It looks to me that you have some sort of bed compensation in use that is causing a 0.4mm adjustment. Please run M122 and see what the "Bed compensation in use" field reports.

Another possibility is that the GCode file you printed uses a M206 commands to offset the Z axis.

lolmodule

No bed compensation: https://gyazo.com/9193b8b3715ef0341789c3e7e04b06f3

Checked the last few files and there are no M206 commands. My start script does have an M207 that has a Z0.4 in it.

M207 S8.5 F4000 T1800 Z0.4 ; setup firmware retraction

Could that be it? like I mention earlier I am not fully up on Gcode so when my friend gave me the scripts for FW retraction I just used them. Is there a reason to have a Z0.4 in the FW retraction?

Phaedrux

The Z parameter for firmware retraction controls Z hop.

lolmodule

Ah ok. I dont know what the issue could be then... Everything appears to be setup right.

Phaedrux

Might be time to give 2.0 a try.

If that doesn't work, you could try backing up all your existing config files from the /sys folder and then starting fresh with a new config bundle generated by the RepRap configurator. It would likely take some tuning and adjusting to get it working properly for your printer again, as the configurator really provides more of a starting point than a final working config. This would also give you a chance to dig into RepRap firmware and gcode a little more which is really quite powerful once you get into it.

I still suspect some binding or skipped steps occasionally, can you verify what the rated current for your z stepper is and whether you're running it at close to 85% of rated?

deckingman

I thought that the 20,000 mm/min (333mm/sec) for the Z move in the end gcode was way too fast (which it is) but then it'll be limited to 1,000 because that's what is in config.g.

Like Phaedrux, I'm also inclined to think it's binding or skipping steps. You could try lower Z acceleration.

lolmodule

It may be that, but like I posted above. I ran that high Accel z move manually and it returned to 0 no problem. ( But that doesn't mean it isn't the cause)

Phaedrux

@lolmodule Just a theory, but at the end of the print the motor may be hot and may not respond the same.

lolmodule

@phaedrux that's possible. I'm running dual leadscrew steppers for my Z so I didn't think it could be that but it's definitely not out of the realm of possibility.

lolmodule

I updated to 2.0. printed a calibration cube. removed the print and sent the head to X150 Y150 Z10 ( 10mm above the center of my bed) and this is the result...

https://gyazo.com/384ec6ddfaa195b510a2755408a18a8c

No more strange offset after a print!

Thanks to everyone for all the help and tips!