Test auto vent operation with petg posing as ABS?
I just completed my "+" upgrade and noticed the print head does not try and open the case vent when I sent a test PETG (that's pretty much all I use) job - I was wondering if I sliced something as ABS, but left PETG in the extruder, would that hurt anything? ABS prints at 220-270 and PETG 220-250. It seems like the print bed temp is the big difference. So if I started a faux ABS job, just to see if the head closes the vent, and cancelled it before the actual print started, that should be ok, right?
BTW the included "+" sticker was worth the $30US this kit cost me 🙂
RE:
Well, I answered my own question. It works. Apparently the C1 retains the last loaded filament which is why it didn't try and open the vent on my first test. However after loading "ABS" (really PETG) and sending an ABS job, sure enough it closed the vent. I cancelled, unloaded the "ABS" and reloaded PETG. I then sent a PETG job and it opened the vent. Cool. Mission accomplished.
Just don't accidentally close the vent and expect it to open it. It only alters its last known state...
RE:
You can fix this by adding this gcode to the Start g-code section. So just after G28 add the M870 line:
...
M84 E ; turn off E motor
G28 ; home all without mesh bed level
M870 {if chamber_minimal_temperature[initial_tool]!=0}C{else}O{endif} ; Open vent for low temp materials
{if chamber_minimal_temperature[initial_tool]!=0}
; Min chamber temp section
...
Next in the End g-code section add this
{if layer_z < max_print_height}G1 Z{z_offset+min(max_layer_z+1, max_print_height)} F720 ; Move print head up{endif}
M870 C ; close vent
...
This will guarantee that before and after a print the vent will be in a known state. I also raised an issue to fix this: https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/4956