A cautionary tale
I'm sure we are all aware of the dangers of using GCode posted on the net but I suspect a great many of us misguidedly treat slicer Start and End code as a different beast. I have a Sovol SV-01 which although a good solid printer, support is light to say the least. I found a profile for Prusaslicer on Facebook (grrr I hate facebook) of all places, it worked fine till I tried to print a cylinder standing up.
G1 X5 Y200 Z100 F1000 ; get nozzle out of way
M104 S0 ; kill extruder temperature
M140 S0 ; kill bed temperature
M107 ; kill fan
M84 ; disable motors
M300 ; beep print finish
Looks pretty innocuous till you realise that anything over 100mm high is in trouble.
I see the end GCode of the Mk3 in Prusaslicer includes a complex sum to raise z just a bit from it's finishing pos and I wondered why they didn't just set relative (G91) and do G1 z30, perhaps historical?
RE: A cautionary tale
Are these the ones that work or should we avoid them?
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Chuck H
3D Printer Review Blog
RE: A cautionary tale
The reason theres a calculation in slicer is that if you are already at or near max z height after printing and you tell it to go up 30mm then you are driving your x axis against the end of travel which doesnt sound particularly pleasant even if it doesnt happen to damage anything. By doing the calculation it only moves up as far as it can if close to max Z
RE: A cautionary tale
This is the very issue that led to me taking a deep dive into gcode. You only have to drive the hot nozzle into a nicely completed print once to learn this lesson! PrusaSlicer handles it very nicely. The Prusa will just make noise if you attempt to raise Z too high, but other printers can lose calibration.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
RE: A cautionary tale
@neophyl
Thanks for the explanation.
RE: A cautionary tale
@charles-h13
re the first line "G1 X5 Y200 Z100 F1000" in the situation where the object is taller than 100, the nozzle will try to move down which I know from the bloody great hole punched into the top of my 5 hour print, is not a great plan
RE: A cautionary tale
@towlerg
have you already tried the following code in the slicer?
; Lift print head
{if layer_z < max_print_height}G1 Z{z_offset+min(layer_z+30, max_print_height)}{endif} ; Move print head up
that should preclude the possibility of a crash ride.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: A cautionary tale
@karl-herbert
I did and it does.