Different calibration cycle for ABS than for PLA?
Hi!
After printing a day or so with PLA, I wanted to try the ABS, so I switched spools, regenerated the gcode for ABS and waited for the heat bed to get to temperature.
And then, I noticed that the printing starts much quicker than with PLA: the printer homes X, then Y, then Z, then extrudes a bit of filament close to (0,0,0), and then .... immediately starts printing. For PLA, it would then do the 9-point calibration, then extrude more filament (now typically a flat line), and only then start printing.
I.e., the 9-point calibration seems to be skipped for ABS. And then, my filament is placed way to high up in the air and I get ABS spaghetti.
I tried manually running the calibration before the print (from the LCD menu), but this did not help: the Z axis is kept too high, consistently, and I consistently get spaghetti.
So: why the difference in calibration between PLA and ABS? And how to do it right?
HT
Re: Different calibration cycle for ABS than for PLA?
More details about the effect: I just compared the generated G code and it seems both start the same (except for missing M107 for ABS):
<pre>
G28
G92 E0.0
G1 X60.0 E9.0 F1000.0
G1 X100.0 E12.5 F1000.0
</pre>
What I am seeing for PLA seems to be that G28 runs the 9 point calibration, including a bit of filament extrusion after the first point. For ABS, G28 seems to skip the 9-point calibration, just does a Z homing, and then continues with the 'G1 X60 E9.0', which I am seeing. This line, in contrast to the PLA print, is not flat, but already too high up in the air.
TL;DR: Same gcode, different G28 behaviour: ABS misses 9-point calibration, Z axis is kept too high.
Re: Different calibration cycle for ABS than for PLA?
Can you please upload the full g-codes?
Re: Different calibration cycle for ABS than for PLA?
More details about the effect: I just compared the generated G code and it seems both start the same (except for missing M107 for ABS):
<pre>
G28
G92 E0.0
G1 X60.0 E9.0 F1000.0
G1 X100.0 E12.5 F1000.0
</pre>
What I am seeing for PLA seems to be that G28 runs the 9 point calibration, including a bit of filament extrusion after the first point. For ABS, G28 seems to skip the 9-point calibration, just does a Z homing, and then continues with the 'G1 X60 E9.0', which I am seeing. This line, in contrast to the PLA print, is not flat, but already too high up in the air.
TL;DR: Same gcode, different G28 behaviour: ABS misses 9-point calibration, Z axis is kept too high.
Hello Henrik,
that sounds unexpected, can you try to insert G80 after G28 in the start gcode and describe what's happening?
If you connect through pronterface or something like that and you manually send G28 to the printer, what does it do?
--------------------------------------------
Michal Prusa
CTO
Re: Different calibration cycle for ABS than for PLA?
Yes, if I put G80 after G28, it behaves just like the PLA version with the original settings (i.e., without the G80, but just the G28).
So, well, that kinda solves my print problems for ABS -- the test print looked fine. 🙂 But it's still strange.
I cannot connect to the printer with the tool you mention, I don't have it (maybe I should install it?). After doing another test print, I will see what exactly it is that makes the printer think it should skip the 9-point calibration. Must be either of the temperature commands before the G28.
Re: Different calibration cycle for ABS than for PLA?
Nope, this is clearly a glitch. Printer needs to do 9 point calibration before every print. Please send us your g-code files as I asked you in the email, so we can investigate and possibly fix it in tomorrows release of FW.
Re: Different calibration cycle for ABS than for PLA?
Hello Henrik,
that sounds unexpected, can you try to insert G80 after G28 in the start gcode and describe what's happening?
If you connect through pronterface or something like that and you manually send G28 to the printer, what does it do?
I'm experiencing same thing, G28 isn't always doing what it should. Sending a manual G28 from pronterface does the whole calibration shebang.
Edit: Running the same gcode file gives different results loading via SD card and sending via pronterface. Weird.
It seems by adding almost any command right after the G28 does the trick. I have some beeps now and it does the calibration.