Extruder pull back
October 09, 2014 03:42PM
Hi Guys.
I'm really close to printing again.
Got my ali rib fitted, kit 5 fitted. Z nut holder fitted.
After some help with extruder pulling back.
I remember this from a while back but forgotten how to sort it.
The extruder feeds in then pullsback.
M83 set to relative not absolute.
So what am I missing?
Thanks

JOn
Re: Extruder pull back
October 10, 2014 08:19AM
You have probably set your slicing program to output extruder moves absolute, but set the Ormerod to relative. It is best to set both to relative moves, but current firmware will now also handle absolute moves (early firmware did not)

Dave
Re: Extruder pull back
October 10, 2014 11:49AM
How does this look?


layer_height = 0.24
; perimeters = 2
; top_solid_layers = 4
; bottom_solid_layers = 3
; fill_density = 0.4
; perimeter_speed = 20
; infill_speed = 20
; travel_speed = 60
; nozzle_diameter = 0.5
; filament_diameter = 1.75
; extrusion_multiplier = 1
; perimeters extrusion width = 0.50mm
; infill extrusion width = 0.87mm
; solid infill extrusion width = 0.85mm
; top infill extrusion width = 0.85mm
; first layer extrusion width = 0.48mm
G21 ; set units to millimeters
M107
M104 S185 ; set temperature
G21 ; set units to millimeters
G90 ; use absolute coordinates
M83 ; use relative distances for extrusion
M140 S65; Set bed temperature
G1 Z5 F200 ; lift nozzle
G1 X2 Y50 F2000; Go to wait for warm position
M116; Wait for all temperatures
G10 P0 S205 R0 ; Set extruder temperature
T1; Select extruder
M116; Wait for all temperatures
M109 S185 ; wait for temperature to be reached
G90 ; use absolute coordinates
M83 ; use relative distances for extrusion
Re: Extruder pull back
October 10, 2014 11:51AM
This is from slic3r

G21 ; set units to millimeters
G90 ; use absolute coordinates
M83 ; use relative distances for extrusion
M140 S65; Set bed temperature
G1 Z5 F200 ; lift nozzle
G1 X2 Y50 F2000; Go to wait for warm position
M116; Wait for all temperatures
Re: Extruder pull back
October 10, 2014 11:59AM
On the Printer Settings tab in slic3r:

1. Do you also have "Use relative E distances" checked?

2. Under Extruder 2, what do you have Retraction set at?

It would help if you can post a complete (small) gcode file that is causing problems, or at least the file up to the end of the first layer, assuming the excessive retraction occurs before the end of the first layer.



Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Extruder pull back
October 10, 2014 12:16PM
OK.
Use relative E is checked in slic3r.
My retraction happens whatever I try to print. So must be a simple setting I'm missing?
Only use 1 extruder
I've posted above a g code file up to first code line, apart from this line G1 Z0.240 F3600.000

Thanks, I know I'll get there...

Edited 1 time(s). Last edit at 10/10/2014 12:17PM by Jon Steward.
Re: Extruder pull back
October 10, 2014 12:39PM
Quote
Jon Steward
OK.
Use relative E is checked in slic3r.
My retraction happens whatever I try to print. So must be a simple setting I'm missing?
Only use 1 extruder
I've posted above a g code file up to first code line, apart from this line G1 Z0.240 F3600.000

Thanks, I know I'll get there...

Post the next few lines - none of the G code file you have so far posted has any extrusion commands (moves with an "E" parameter).

In Slic3r, the relevant general printer settings should be
G-code flavour - RepRap (Marlin/Sprinter/Repetier)
Use relative E distances - checked
Extruders: 1
Use firmware retraction - unchecked

Under Extruder 1 (printer settings)
Extruder offset: x:0 y:0

Retraction
Length: 4 or 5
Lift Z: 0
Extra length on restart: 0

Retraction when tool is disabled (should not make any difference)
Length: 0
Extra length on restart: 0

Dave

Edited 1 time(s). Last edit at 10/10/2014 12:40PM by dmould.
Re: Extruder pull back
October 10, 2014 02:00PM
All is set in slic3r as you've detailed above
here's some code

G1 X65.529 Y74.457 F3600.000
G1 X67.569 Y72.697 E0.13020 F600.000
G1 X67.579 Y72.707 E0.00068
G1 X68.069 Y72.307 E0.03057
G1 X68.999 Y71.757 E0.05221
G1 X71.449 Y70.567 E0.13162
G1 X72.249 Y70.237 E0.04182
G1 X73.089 Y70.027 E0.04184
G1 X75.759 Y69.527 E0.13126
G1 X76.349 Y69.437 E0.02884
G1 X76.949 Y69.417 E0.02901
G1 X122.999 Y69.417 E2.22527
G1 X123.599 Y69.437 E0.02901
G1 X124.189 Y69.527 E0.02884
G1 X126.869 Y70.027 E0.13174
G1 X127.909 Y70.307 E0.05205
G1 X128.559 Y70.607 E0.03459

Edited 1 time(s). Last edit at 10/10/2014 02:06PM by Jon Steward.
Re: Extruder pull back
October 10, 2014 04:42PM
How far does the print get before the extruder retracts too much?



Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Extruder pull back
October 10, 2014 05:55PM
Yes, those are definitely relative extruder moves. As well as answering David's question, take a look through the G code for negative extruder moves - they are the only moves that should result in the filament retracting. The only moves you should see are those for the distance you have set to retract, but those should each be paired with a positive move for the same distance a move or two later. If the G code looks OK there is something peculiar going on - are you certain that the G code you are looking at is the same file that is on the SD card you are printing from? It may be an idea to delete the file from the SD card and replace with the one you are looking at just to be sure, Also double-check that the extruder motor is definitely connected to the correct pins on the Duet (and in the same colour order as the motor connector). You should also check the motor operates in the correct sense - i.e. when you command a retraction from Pronterface it retracts filament, and when you command a feed it feeds. If it operates in the wrong sense, reverse the order of the motor connections on the Duet.

That covers just about everything I can think it could be.

Dave
Re: Extruder pull back
October 11, 2014 04:23AM
I'm now printing again perfectly and not exactly sure what sorted it.
1. Reloaded SD image file. Didn't sort it.
2. Checked motor connections. All OK.
3. Reset Z probe height using IR sensor and away she went. Printed a perfect snowman!
The only other thing I can think of that I noticed different was that the nozzle was too close to the glass.
Anyway.
Thanks for all your help.
Much appreciated.
Jon
Re: Extruder pull back
October 12, 2014 08:16AM
Quote
Jon Steward
I'm now printing again perfectly and not exactly sure what sorted it.
1. Reloaded SD image file. Didn't sort it.
2. Checked motor connections. All OK.
3. Reset Z probe height using IR sensor and away she went. Printed a perfect snowman!
The only other thing I can think of that I noticed different was that the nozzle was too close to the glass.
Anyway.
Thanks for all your help.
Much appreciated.
Jon

OK - so you were not seeing a retraction, but seeing the extruder motor skipping (with clicking noises) because the nozzle was blocked by being too close to the glass and the extruder could not push plastic through. You will soon get a feel for setting the correct Z height before starting the print - it is critical and probably best to set it manually a few times (with the paper method) so you know what it should be before using the automatic IR Z homing, and then check that the IR is setting it correctly and consistently before relying on it.

Dave
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