Extruder running too fast

I'm trying to upgrade my gen6, mendel, marlin to Slic3r/pronterface from skeinforge/repsnapper.

I calibrated my extruder so using the slicer is nicer tutorial. I arrived at 6400 steps/mm and the measured amount of filament matches the extrusion length in Pronterface.

The problem is when I try to print a part generated in Slic3r, the extruder is moving way too fast causing jams. The extruder is also retracting 10mm when I have it set to 1 mm. Changing the speeds in Slic3r does not help, as it slows down the x,y,z axis as well as the extruder.

edit: I am running slic3r 0.9.0

Edited 1 time(s). Last edit at 08/09/2012 11:25AM by stabbs.

Sorry if this sounds confusting- My brains are so scrambled right now trying to get this to work the past 2 days.

According to this thread I can adjust the extrusion multipler in slic3r to compensate- but this can effect build quality. I had calibrated my e-steps in pronterface but maybe I should somehow calibrate it using slic3r??

Could somebody also please explain why extrusion speed is expressed in mm/min in Pronterface but mm/sec in Slic3r? Shouldn't these units be the same in both programs?

Edited 1 time(s). Last edit at 08/09/2012 12:42PM by stabbs.

I'd say your steps per are off by a factor of 10.
All the interface is doing when you tell it to retract by 1mm is sending a G1 E-1 in relative mode, if it's retracting 10mm your extruder is incorrectly calibrated.
640 would be closer to the norm for a Greg's style extruder.

But it is correctly calibrated in pronterface- I am getting the correct measured amount when I manually extrude. It's when I print gcode that my extruder is running way too fast.

Tonight I'll try setting the extrusion multiplier to .1 to compensate but from what I have read this will lower the quality of the print.

6400 is definitely wrong unless you have a planetary geared extruder with 50:1 reduction. Did you calibrate so it moves 10mm of filament when the button is pressed? All modern slicers produce volumetric E values that are the length of filament going into the extruder not coming out.

---

FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

The extruder multiplier is just a hack to work around an incorrect E-steps value.
If as you say in your first post when you retract 1mm it retracts 10mm the extruder is not correctly calibrated.
Pronterface just sends GCode just like when running the program.

The only other thing I can think of that would throw it off by a lot is if it was set to inches not mm either during calibration or during the print, look at the GCode you are running and make sure there is a G21 near the top and no G20.
Type G21 into pronterface then check it's extruding/retracting the correct amount.
But again that would be off by 25x not the 10 you seem to be seeing.

Quote
Polygonhell
The only other thing I can think of that would throw it off by a lot is if it was set to inches not mm either during calibration or during the print, look at the GCode you are running and make sure there is a G21 near the top and no G20.
Type G21 into pronterface then check it's extruding/retracting the correct amount.
But again that would be off by 25x not the 10 you seem to be seeing.

I looked at the gcode and its set to G21.

Quote
Sublime
6400 is definitely wrong unless you have a planetary geared extruder with 50:1 reduction. Did you calibrate so it moves 10mm of filament when the button is pressed? All modern slicers produce volumetric E values that are the length of filament going into the extruder not coming out.

Yes 6400 is correct for my extruder. I have an unconventional drive and it is extruding the correct amount.

I reinstalled all the software and updated Marlin and I still have to set the extrusion multiplier to .1.

When you extrude 100mm in pronterface it sends a G1E100 to Marlin. If slic3r wanted to feed 100mm it would also send G1E100. The same command and the same firmware does both. How would Marlin know the command came from Slic3r instead of Pronterface and feed 10 times less? The only unusual thing is you would never get a filament run that needed 100mm of filament, the numbers would be always be smaller.

What happens if you type G1E1F200 in Pronterface? Does it feed 1mm or 10mm into the extruder?

What have you set the filament diameter to in Slic3r? If you set it to say 1mm and you have 3mm filament it would feed it about 10 times too fast.

---

[www.hydraraptor.blogspot.com]

Thanks for all the replies- been busy the last few nights but I found some time tonight to experiment. I disconnected my hot end from the drive so the filament is uninhibited.

Quote
nophead
What happens if you type G1E1F200 in Pronterface? Does it feed 1mm or 10mm into the extruder?

It is feeding 1mm. I had to lower the speed though from F200 to F30. My moter whines and stalls at F200.

Quote
nophead
What have you set the filament diameter to in Slic3r? If you set it to say 1mm and you have 3mm filament it would feed it about 10 times too fast.

I measured my filament and set this to 2.8.

Lowering the extrusion multiplier to .1 was a bit low but close. I will adjust this setting tomorrow night and try to kick out a print.

How have you calibrated your extruder? Where are you entering in this value for use during printing? In you firmware image directly? Or are you comimiting the derived E steps value via the M5xx save to EEprom command via pronterface? Or are you simply entering this value as a start command in the advanced section of slic3r (I.e. M92 E6400)?

Try this: Enter the M92 E6400 command into pronterface and then without power cycling the electronics try to extrude 10mm of filament or whatever and check if you get the same.

If its correct then this is the correct E steps value and you are simply not using this during printing by not storing/slicing with it as your E step cal value.

If its not extruding as you expect after the M92 command then it's simply wrong and you messed up the process somewhere.

I don't see how you can say the extruder goes 10 times too fast if it won't do F200. With so much gearing one would think it would stall because the extruder motor is already having to go 10 times faster than normal to run at the correct speed.

Can you post the first few lines of your G code so we can see what the E codes look like.

Edited 1 time(s). Last edit at 08/14/2012 07:57AM by nophead.

---

[www.hydraraptor.blogspot.com]

; generated by Slic3r 0.9.1 on 2012-08-14 at 20:58:32

; layer_height = 0.4
; perimeters = 3
; solid_layers = 3
; fill_density = 0.4
; perimeter_speed = 30
; infill_speed = 30
; travel_speed = 130
; scale = 1
; nozzle_diameter = 0.5
; filament_diameter = 2.8
; extrusion_multiplier = .2
; single wall width = 0.53mm
; first layer single wall width = 0.80mm

M104 S190 ; set temperature
G28 ; home all axes
M109 S190 ; wait for temperature to be reached
G90 ; use absolute coordinates
G21 ; set units to millimeters
G92 E0
M82 ; use absolute distances for extrusion
G1 Z0.400 F7800.000
G1 X82.820 Y83.010
G1
G1 X83.210 Y82.630 F540.000 E0.00520
G1 X83.630 Y82.290 E0.01037
G1 X84.080 Y81.980 E0.01559
G1 X84.550 Y81.710 E0.02077

Edited 1 time(s). Last edit at 08/14/2012 09:16PM by stabbs.

So if I work out the length of the first line I get 0.54mm.

If I work out the volume of that as a 0.8 x 0.4mm rectangle I get 0.174mm^3.

When I work out the volume from the E value I get 0.032mm^2, which is about 5 times smaller than it should be, corresponding to extrusion_multiplier being 0.2. The reason it is not exact is because the filament is not quite a rectangle, it has rounded corners.

So slic3r is doing the right thing. I can't see why you get too much plastic when using it and don't when sending the same codes from Pronterface. The only thing unusual is your steps per mm is very high. Perhaps there is a problem with the maths in Marlin that only affects small E values or certain speeds.

I have never been able to get the right flow rate with Marlin on my first layer, if it do it slowly the flow rate seems too low. The faster I do it, the more correct is seems to be. I still haven't got to the bottom of that.

Edited 1 time(s). Last edit at 08/15/2012 04:24AM by nophead.

---

[www.hydraraptor.blogspot.com]

So it turns out Slicer was working perfectly well all along. I was extruding fine in the air but the added back pressure when printing close to the print bed was causing slipping and a leak in the nozzle. Everything has been rebuilt and is working great now.

Thanks so much for all of the help you guys provide on this forum. I am really psyched to be printing now