Extruding too much filament before printing?  

Re: Extruding too much filament before printing?

See my no ooze mesh bed levelling thread.

Here is my current form of the printer start G-Code
M115 U3.2.1 ; tell printer latest fw version
M201 X1000 Y1000 Z1000 E9000 ; 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 X8 Y8 Z0.4 E1.5 ; sets the jerk limits, mm/sec
M205 S0 T0 ; sets the minimum extruding and travel feed rate, mm/sec
M83 ; extruder relative mode

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==0.05}100{else}95{endif}


Regards,
Martin

Re: Extruding too much filament before printing?

Thanks for the response Martin. One quick question though - should your code replace the existing code in Slic3r, or should it be added alongside it? I'm assuming it should replace it, but I want to be sure.

EDIT: Yes, it has to replace the original G-code. It has resolved that problem. Now to solve the rest of the problems!

Re: Extruding too much filament before printing?

Glad I could be of help.

Regards,
Martin

Re: Extruding too much filament before printing?

I have the same problem (see my post) but I can't understand how you solved it. What is the original g-code? You deal with slic3r, but I have that excess of filament coiling out even if I print sd card preloaded models, even without connecting the printer to the PC. Can you tell me what to do exactly, please?

Edit: ok, I've understood the changes you did in slic3r: you keep the extruder temp at 160 while you do preliminary 9 points, then you heat it to target temperature after those steps, in order to minimize coiling. But if I modify my g-code in slic3r, then how I write it on the printer firmware? And is it valid for all the presets, or just for pla prints? Is not 160 too low for a PETG or ABS loaded filament? Do that types of plastic not coil?

Re: Extruding too much filament before printing?

I have just discovered and understood this too. Although it feels like the pre-print routine is a printer firmware setting, it's not.

The gcode has the "directions" for how to draw, but also the pre-draw, as different models will require different temps, or different acceleration/ speed, etc..

Therefore this code is put into your slicer, and is included with every gcode, which is what you put on the SD card and print.

However, just using the old code someone's posted here is probably not as good as modifying your own existing code.

I'm going to comment on that on the other thread.

Re: Extruding too much filament before printing?

@david.m86 I agree with you the code I pasted needs changing. Prusa themselves have updated part printer start G-Code since I made my last post and as a result I incorporated their changes. Also I have since changed to a volcano heater block and so my maximum feed rates are different.

My code should only be used for hints. It's main trick is to do a partial heating on the extruder before the mesh bed levelling. That is the critical part of the code. In the code I posted the partial extruder temperature is 160°C.

Regards,
Martin

RE: Extruding too much filament before printing?

@martin-w15

I am new to this where do you copy and paste the g code to in slicer? And do you need to do it every time or does slyer save the g- code 

RE: Extruding too much filament before printing?

Printer settings, in the custom gcode, startup. You change the code once, then save it as a new printer profile. Then after you select that profile, PSlicer generally remembers the printer you've selected.

And you need to have EXPERT selected.

RE: Extruding too much filament before printing?

@tim-m30

You type all three pages of code into that section you talked about.  In the exact order you have it from top to bottom and that will hopefully solve my extruder from having filament come out while it is warming up? 

RE: Extruding too much filament before printing?

@syqraz

No - the above is partial. Here's my complete startup gcode (copy paste works) -- BUT: this is for a Prusa MK3, not the MK3S.  There could be minor differences - but it should be okay. 

Known issues are:

1) your M115 line should match whatever you are using today.
2) my scribble purge may not work well for you
3) it slows down prints, sometimes a lot, but worth the extra time, IMHO
4) seasonal changes in room temperature affect the time it takes: I change the set point based on where I keep my house set.

M115 U3.7.1 ; tell printer latest fw version
G90 ; use absolute coordinates
M83 ; extruder relative mode

; cool down PINDA
M106 S255 ; turn on fan
M104 S0 ; turn off nozzle heat
M140 S0 ; turn off bed heat
M860 S35 ; wait until PINDA is less than 35C
M106 S0 ; turn off fan

; preheat nozzle to a low temp, get plastic mushy before driving into the bed with G28
M140 S[first_layer_bed_temperature] ; set bed temp
M109 S175 ; wait for extruder temp
M190 S[first_layer_bed_temperature] ; set & wait for bed temp
G28 W ; home all without mesh bed level

; soak PINDA then level
G0 X50 Y50 Z1 F3000; this is a good PINDA heating position
M860 S37.5 ; wait until PINDA is >= 35C in winter, 37.5C spring/fall, 40C summer
G80 N7 R5; mesh bed leveling

; heat to extrude temp
G0 X0 Y-3.0 Z10 F3000; this is a good nozzle heating position
M109 S[first_layer_temperature] ; set & wait extruder temp

; purge
G1 Y-3.0 Z0.20 F1000.0 ; go outside print area
G92 E0.0
G1 X1.0 Y-1.0 E0.5 F500.0 ; scribble 1
G1 X1.0 Y-3.0 E0.5 F500.0 ; scribble 1
G1 X2.0 Y-1.0 E0.5 F500.0 ; scribble 2
G1 X2.0 Y-3.0 E0.5 F500.0 ; scribble 2
G1 X3.0 Y-1.0 E0.5 F500.0 ; scribble 3
G1 X3.0 Y-3.0 E0.5 F500.0 ; scribble 3
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.0 F1200.0 ; intro line
G1 X97.0 F2000.0 ; wipe left
G1 X105.0 F3000.0 ; wipe right
G92 E0.0

M221 S{if layer_height<0.075}100{else}95{endif}

; end Printer Start gcode

RE: Extruding too much filament before printing?

@tim-m30

Thanks