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How to automatically pre-heat HB *before* pre-heating hot end  

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dimprov
(@dimprov)
Noble Member
How to automatically pre-heat HB *before* pre-heating hot end

Especially when printing PETG, the HB takes much longer to heat up than the hot end. The result is a lot of oozing leakage of PETG out of the nozzle while waiting for the HB to reach temeprature. This is a problem, because it can interfere with the print.

Is there a way to force the HB to temperature first, so that when the hot end reaches temperature, it can immediately start printing (i.e. limiting the time for oozing?). Likewise, for the same reason, it would be best if the MK3 could do it's 9 point calibration *before* raising the hot end to the printing temperature. Otherwise, it's oozing during the calibration as well.

Anyone know?

Posted : 08/05/2018 3:51 am
Joe Prints
(@joe-prints)
Estimable Member
Re: How to automatically pre-heat HB *before* pre-heating hot end

This is the start Gcode I run to do that exact thing

M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M104 S[first_layer_temperature] ; set extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp
M300 S1567 P240 ; Play a Beep
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling

Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints

Posted : 08/05/2018 4:51 am
Kwaad2
(@kwaad2)
Honorable Member
Re: How to automatically pre-heat HB *before* pre-heating hot end

here's mine. It's the best of both worlds.

It will "start" the nozzle preheat to "first layer temp - 40c"
then start the bed preheat, and wait. Once the bed preheat finishes, the part cooling fan turns on, and the nozzle pre-heats to "first layer temp" It then performs 9 point calibration. (You don't get little oozy bits on the PEI sheet, becuase the fan "cools" the outside of the blob which prevents it from sticking to anything)

Once 9 point calibration is finished, the fan turns off, it prints the "prime line" and prints normally.

I generally have no oozing issues, or "blobs" on my prints.

THIS IS FOR SLIC3r


M115 U3.1.1-RC5 ; tell printer latest fw version
M201 X1000 Y1000 Z200 E5000 ; sets maximum accelerations, mm/sec^2
M203 X200 Y200 Z12 E120 ; sets maximum feedrates, mm/sec
M204 S1250 T1250 ; sets acceleration (S) and retract acceleration (T)
M205 X10 Y10 Z0.4 E2.5 ; sets the jerk limits, mm/sec
M205 S0 T0 ; sets the minimum extruding and travel feed rate, mm/sec
M83 ; extruder relative mode
M104 S{first_layer_temperature[0] - 40} ; Set nozzle temp 40c below first layer temp.
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
{if first_layer_temperature[0] < 241}M106 S255{endif} ; wait extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
G1 Y-3.0 F1000.0 ; go outside print area
M106 S0 ; Turn cooling fan off before printing anything
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}

Hi, I'm Sean. I used to work on CNC machines.
I try to not make mistakes, but the decision is YOURS.
Please feel free to donate to my filament/maintance fund.

Posted : 08/05/2018 6:02 am
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: How to automatically pre-heat HB *before* pre-heating hot end

Into what file should your code for SLIC3R go?

Posted : 08/05/2018 2:30 pm
Kwaad2
(@kwaad2)
Honorable Member
Re: How to automatically pre-heat HB *before* pre-heating hot end


Into what file should your code for SLIC3R go?

In the top box, where it says "Start G-Code"

I would advise you to "backup" your code in there, in case you don't like any of the changes. 🙂

Hi, I'm Sean. I used to work on CNC machines.
I try to not make mistakes, but the decision is YOURS.
Please feel free to donate to my filament/maintance fund.

Posted : 08/05/2018 3:54 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: How to automatically pre-heat HB *before* pre-heating hot end

It seems to ooze even at the lower temperature threshold.

Posted : 19/05/2018 4:02 am
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: How to automatically pre-heat HB *before* pre-heating hot end

I guess some amount of oozing is just inevitable. So, what I did was change the end g-code to this:
G1 X0 Y200 Z180; home X axis

to hopefully raise the z-axis to 180mm when it's done. That way, on the next print, when it starts oozing at the beginning, it's easier to reach and manually remove the oozement remove before the print starts.

Posted : 19/05/2018 3:11 pm
stahlfabrik
(@stahlfabrik)
Honorable Member
Re: How to automatically pre-heat HB *before* pre-heating hot end

So that you crash into the print if it is higher than 18cm?

Posted : 19/05/2018 6:41 pm
Fotoman
(@fotoman)
Trusted Member
Re: How to automatically pre-heat HB *before* pre-heating hot end

Try the gcode form this thread: https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/no-ooze-mesh-bed-leveling-in-slic3r-pe-1-39-2-t17889.html . It works great for me.

Proud owner of a Mk3 that is producing very nice prints. There is room for improvement as I learn more about it, but so far I am very happy.

Posted : 19/05/2018 6:43 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: How to automatically pre-heat HB *before* pre-heating hot end


So that you crash into the print if it is higher than 18cm?

What's your solution?

Posted : 20/05/2018 2:49 pm
Joe Prints
(@joe-prints)
Estimable Member
Re: How to automatically pre-heat HB *before* pre-heating hot end

What's your solution?
I believe stahl is implying that if you were to print something taller than 180mm the nozzle will crash into the print upon print completion.
I suggest if you are trying to move the nozzle up at the end, change the value to 219 (max 220)

Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints

Posted : 20/05/2018 4:14 pm
stahlfabrik
(@stahlfabrik)
Honorable Member
Re: How to automatically pre-heat HB *before* pre-heating hot end

Exactly thank you.

I personally do not raise z after print.

Posted : 20/05/2018 6:31 pm
Joe Prints
(@joe-prints)
Estimable Member
Re: How to automatically pre-heat HB *before* pre-heating hot end

When I start a print, I hold the knob down to access the fast Z adjust and move it up far enough to pull the ooze off before it starts the job

Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints

Posted : 20/05/2018 6:45 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: How to automatically pre-heat HB *before* pre-heating hot end


When I start a print, I hold the knob down to access the fast Z adjust and move it up far enough to pull the ooze off before it starts the job

That's exactly what I used to do.

I wonder whether upgrading to the volcano would help? Presumably it heats up much faster, so maybe there'd be less ooze.

Anyone here have one and know?

Posted : 20/05/2018 8:19 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: How to automatically pre-heat HB *before* pre-heating hot end

In his review of the volcano, sensei Tom says that the volcano has much less oozing:

which is good enough for me. I'm ordering one!

Posted : 20/05/2018 10:34 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: How to automatically pre-heat HB *before* pre-heating hot end

Oops. Maybe not. Sounds like the upgrade path from the I3 MK3 is still rather fuzzy: https://shop.prusa3d.com/forum/general-discussion-announcements-and-releases-f61/mk3-0-8mm-nozzle-t17563.html

Posted : 21/05/2018 1:56 am
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