<@&1304550334839918672>: Can someone help please? I have my BT almost working but the filament fails to unload. I have XOL Metrix cutter and Tool Start / Tool End sensors. They all seem to be working fine. I can load filament into the printhead OK but when I try to unload it, first it cuts OK but then tries to pull back the filament unsuccessfully. What seems to be missing is a reverse movement of the extruder to clear the filament from the extruder gears. I have looked through all the settings but cannot see what I need to do to enable the step. Can someone poiunt me in the right direction please?@
#[solved] Unload failing
echo tree
brazen swallowBOT
Please run this debugging script when not printing and post the resulting link in chat.
echo tree
Thank you. Link is https://termbin.com/unp0
dire heath
I don’t see an unload command, mostly just a ton of calibration
echo tree
I havent tried the unload for a day or two. Shall I try it now and upload the logs again?
dire heath
Please video it and then rerun the script
echo tree
OK -will do
echo tree
The new log is at https://termbin.com/z2lbz
The video I made is here: https://www.dropbox.com/t/x6BrCrjPEtrlae15
dire heath
Interesting it’s trying to retract, does it move if you give a retract from klipperscreen?
echo tree
Yes - I did that afterwards and it worked OK (I realised I should have included that in the video.
During the failed retract, the box turtle motor is trying to pull it.
Ive had another look at the config files and I think the problem mauy be caused by the commented out lines in this section:
'''
[AFC_extruder extruder]
pin_tool_start: !EBBCan: PD0
pin_tool_end: !EBBCan: PA15
tool_stn: 72 # See documentation for details on how to calculate this value. https://armoredturtle.xyz/docs/afc-klipper-add-on/toolhead/calculation.html
# tool_stn_unload: 100 # See documentation for details on how to calculate this value. https://armoredturtle.xyz/docs/afc-klipper-add-on/toolhead/calculation.html
tool_sensor_after_extruder: 0 # Extra distance to move in mm once pre/post sensors are clear. Useful for when only using post sensor, so this distance can be the amount to move to clear extruder gears
tool_unload_speed: 25 # Unload speed in mm/s when unloading toolhead. Default is 25mm/s.
tool_load_speed: 25 # Load speed in mm/s when loading toolhead. Default is 25mm/s.
tool_stn: 79 # the folllowing are from the AT config instructions
t
'''
restive vortex
In the video, it looks like the toolhead extruder is trying to retract but is stalling/skipping. Has the cutter worked for you in the past? Do you have a hotend jam?
echo tree
The cutter is working fine because when I do a klipper retract after a cut it works fine. I dont think the toolhead extruder is doing anything. The little skip I saw was just because of the tension that the Box turtle put on it
restive vortex
Got ya. I need to look into your termbin you posted above. Not my strongest skill, but I'll see if anything pops out at me. I'm sure mc-red will find it long before I do 
dire heath
From what I can see it was commanded to retract several hundred mm, the settings look to be fine that’s why I asked if manual retract works,
Let’s do this
Get it loaded if you undid that
Extruder 100mm
Run afc_cut
Using normal commands retract until you see the tool_end switch come un made note how far this took
Keep retracting until tool_start is unmade note this distance remove filament from tool head and take a picture
Report back
echo tree
Actually, I did that earlier. The Tool_end triggered at 90 and the Tool_start at 120.
However, all this fiddling around has caused my toolhead to develop a blockage (it wasnt there earlier) so I will need to clear that before I progress any further
dire heath
Those values sound huge for a toolhead as small as XOL. I suspect your cut is not working
echo tree
The version of XOL with the tool_end switch and cutter was quite a bit longer than the original. I am sure the cutter was working as the end of the filament was clean cut across. Also, after a cut I was able to retract easily with the toolhead cold.
I've had to completely disassemble my toolhead due to a blockage and found some very small neatly cut pieces blocking the extruder gears.
When I finish putting it back together I'll double check everything. Thanks for your help so far. I'll get back to you when I have got it working again
worn cave
Sensor after extruder set to zero with using two sensors isn’t going to be correct. Either way you’re going to need to properly tune these values. This isn’t the first time we’ve had problems reported with the “recommended” values for xol, so if you spend the time to do the tuning let us know where you land with them.
Also when you’re testing, make sure you extrude enough filament through the hotend that the cut has been melted after you load, and before you unload
dire heath
Oh you know I completely forgot about that setting
worn cave
Oh you know I completely forgot about that setting
Yeah, that second sensor is really quite vestigial at this point. Using just the top sensor should work perfectly fine. In this case the bottom/second sensor needs to be left undefined in the config.
echo tree
Hi. I'm back again
I've rebuilt my toolhead. I am 100% sure that the cutter is working as it should but I am still getting the same issue.
The measurements I have taken are as follows:
retract until you see the tool_end switch come un made note how far this took. - 10mm
Keep retracting until tool_start is unmade note this distance - 30mm
Peter
dire heath
Did you set that 30 as the sensor after extruder value?
echo tree
I know its a long time since I have posted. Its a long story but my RPi SD card stopped working and the klipper-backup had also stopped working. So I only had a very old backup to restore from.
I had to rebuild the entire Klipper installation which has taken ages.
I am noew back to the point I was before and testing the unload again - it was the same behaviour.
However I set tool_stn_unload to 30 and disabled the "sensor after extruder" and it now retracts as expected.
I am left with a really odd problem in that while the cutter works fine first time, the next time I run unload, the cutter arm misses the stop bu about 10mm. I'm sure theres a simple explanation but it seems as if the homing has been uncalibrated
dire heath
Are you skipping steps during cut?
echo tree
I wondered that but its the Y axis that is out. I havent had a chance to investigate it properly yet
dire heath
That’s my only guess without more info
echo tree
I'm sure I'll sort it
echo tree
I think I have found the cause of the unload failure problem. It seems that my extruder stepper is not happy to unload at the default 25mm/sec setting. I have changed tool_unload_speed to 15mm/sec and it now unloads correctly. I dont know it there is a stepper setting that will improve the stepper performance or whether to just leave it at a lower setting.
The other problem with the homing offset is, I think, caused by the brush cleaner which is set a bit low and stalling the y movement 🤞
echo tree
I was right about the brush causing the Y homing upset but the reason was actually that I needed to do a QGL first as the back left gantry was low. That was causing the nozzle to catch on the bed when parking after a brush.
The other problem with unload failure is working perfectly now. Phew! Its been a bit of a marathon but also a big learning experirnce for me.
worn cave
You could have a look at TMC autotune, technically you can use this on extruders too, and you might be able to get a little more performance out of it
Double check your extruder's tension too, not sure which you're running. It's possible that you've got it too tight and the motor is having to fight that (this is just a guess)
echo tree
It's all working great now. All lanes load and unload with no problem. I've increased the run_current from 0.65 to 0.8.
Need to do some printing now! Thanks for your help and patience