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[Solved] Extruder calibration?  

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Filnet
(@filnet)
Active Member
Extruder calibration?

Hello

During mesh calibration (before printing), some PLA is extruded and make a pellet which fall on the first layer. 

Could you explain me why and perhaps tell me what to do? Hotend too hot? 

Thanks for your help.

 

 

Posted : 10/05/2019 7:37 pm
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(@)
Illustrious Member
RE: Extruder calibration?

Common problem, many of us do all the calibration steps before heating the nozzle to print temperatures.  Here's how I do it in my Printer Settings Custom Gcode.  
(ps: I am using a special version, so my G80 command is non-standard, but should work with stock firmware)

M115 U3.4.0 ; tell printer latest fw version
M83 ; extruder relative mode
G28 W ; home all without mesh bed level (cold zero to get PINDA low)
M104 S185 ; set extruder partial temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S185 ; wait for extruder temp
M860 S35 ; wait for PINDA temp to stabilize
; G4 P15000 ; wait another 15 seconds to warm PINDA
G28 W ; home all without mesh bed level (hot)
G80 N7 ; mesh bed leveling N7 = 7x7 ?
G91 ; move relative
G1 Z10
M109 S[first_layer_temperature] ; wait for extruder temp
G1 Z-10
G90
G1 Y-3.0 F1000.0 ; go outside print area
G92 E0.0
G1 X60.0 E9.0 F1000.0 ; intro line pt 1
G1 X100.0 E12.5 F1000.0 ; intro line pt 2
G92 E0.0
M221 S{if layer_height==0.05}100{else}95{endif}
This post was modified 2 years ago by --
Posted : 10/05/2019 7:54 pm
Filnet
(@filnet)
Active Member
Topic starter answered:
RE: Extruder calibration?

thanks to you!

With your help, I solved my problem and took my first steps in G-Code! Here is the procedure that I adapted with my default firmware with your code:

 

M115 U3.6.0 ; tell printer latest fw version
G90 ; use absolute coordinates
M83 ; extruder relative mode

G28 W ; home all without mesh bed level (cold zero to get PINDA low)
M104 S185 ; set extruder partial temp
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S185 ; wait for extruder temp

;M860 S35 ; wait for PINDA temp to stabilize (is this important?)

G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
M104 S[first_layer_temperature] ; set extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp
G1 Y-3.0 F1000.0 ; go outside print area
G92 E0.0
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line
G92 E0.0
M221 S{if layer_height<0.075}100{else}95{endif}

This post was modified 2 years ago 2 times by Filnet
Posted : 10/05/2019 8:56 pm
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(@)
Illustrious Member
RE: Extruder calibration?

M140 S[first_layer_bed_temperature] ; set bed temp << not needed, M190 both sets and waits for the bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp

M860 S35 ; wait for PINDA temp to stabilize  << this is essential, trust me

M104 S[first_layer_temperature] ; set extruder temp << again, not needed, M109 both sets and waits for the nozzle temp
M109 S[first_layer_temperature] ; wait for extruder temp

 

The lift and wait code in my first reply raise the nozzle off the bed, and helps prevent some cooking of the PEI surface.

This post was modified 2 years ago by --
Posted : 11/05/2019 12:31 am
Filnet
(@filnet)
Active Member
Topic starter answered:
RE: Extruder calibration?

Ok. I delete these lines.

You are right for for the lift code because I needed to make the lift manually. Your code is better, I add these lines.

For PINDA, I red this night that this is necessary to have a stabilized temperature but why this line isn't in the default firmware?

Posted : 11/05/2019 6:15 am
Vojtěch
(@vojtech-3)
Honorable Member
RE: Extruder calibration?
Posted by: philippe.b16

For PINDA, I red this night that this is necessary to have a stabilized temperature but why this line isn't in the default firmware?

Because, depending on the ambient temperature, the PINDA may never reach 35°C and thus the print would never start. The default gcode in Slic3r assumes that the printer has a properly calibrated Temperature calibration and thus preheating the PINDA is theoretically superfluous.

In reality, OCXOs work better than TCXOs, and so does preheated PINDA work better than a temperature-calibrated PINDA. So people who hack their gcode to get the best out of the printer prefer to wait for the PINDA to reach a preset temperature.

Posted : 11/05/2019 8:37 am
Filnet
(@filnet)
Active Member
Topic starter answered:
RE: Extruder calibration?

Votre explication est claire! Merci

Posted : 11/05/2019 8:43 am
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(@)
Illustrious Member
RE: Extruder calibration?

The wait for PINDA to reach a temp is that the PINDA trigger range is temperature sensitive, and when the bed level runs, a print with a cold printer will require a different Z-offset than starting a print with a warm printer.  Even after a PINDA PID calibration, the PINDA is sensitive enough to cause issues in your first layer. 

Waiting for 35c pretty much ensures each print can use the same Z-offset.  Some who print hotter most of the time or have enclosures use 40c as their baseline.

This post was modified 2 years ago 2 times by --
Posted : 11/05/2019 8:51 am
Filnet
(@filnet)
Active Member
Topic starter answered:
RE: Extruder calibration?

Ok Tim. I make a preset for filaments with more hot temperature. Thanks

 

Posted : 11/05/2019 9:00 am
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(@)
Illustrious Member
RE: Extruder calibration?

The PINDA wait has no on-screen notice: so if your nozzle and bed reaches programmed temperatures but the printer seems "stalled" give it five minutes.  I tried to use 40c with PLA temps, and was not able to get the PINDA that warm - even after 30 minutes.  I backed the temp down until the delay was acceptable and found 35c to provide a good and repeatable layer one print after print. Combined with the 7x7 mesh level, I haven't touched z-offset for months except for nozzle changes.

Posted : 11/05/2019 9:09 am
Filnet
(@filnet)
Active Member
Topic starter answered:
RE: Extruder calibration?

Finally, I set 33c because the time with 35c is more than 15mn.

 

Posted : 11/05/2019 9:00 pm
bobstro
(@bobstro)
Illustrious Member
RE: Extruder calibration?
Posted by: philippe.b16

Finally, I set 33c because the time with 35c is more than 15mn.

 

You might want to check the evenness of your bed's heating. I found the home (bottom left) position didn't get quite as warm as other positions, so I move the nozzle to the back-center and lower it for heating. It can still take a while on a cold day, but it's a little faster. Positioning it there also lets me inspect the print surface and do any last-minute adjustments.

My notes and disclaimers on 3D printing 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...
Posted : 11/05/2019 9:28 pm
bobstro
(@bobstro)
Illustrious Member
RE: Extruder calibration?

Stupid edit time...

Prusa uses X=50, Y=50 for the warmup position as does the Prusa owner's wiki. Tailor to suit your printer environment. The warmer the spot the quicker it'll go.

My notes and disclaimers on 3D printing 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...
Posted : 11/05/2019 9:36 pm
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