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Gcode for retraction (timelapse picture)

Posted by ChicoCyberGoth 
Gcode for retraction (timelapse picture)
November 12, 2018 10:13PM
Hello people.

I'm trying to make a timelapse of the printing.
My idea was, every layer change I add a gcode to:
1. move extruder out of the way and always in same position.
2. move bed to the full front.
3. control a small servo to click my camera shutter
4. wait some seconds
then continue printing.

It worked nicely, but, when it is waiting the camera shot the extruder oozes, when printing resumes the extruder brings that ooze in the actual print, which makes bad defects in the final print.
I believe if I implement a filament retract the problem may solve (what do you think?), but I dont know how to do, so I'm asking your help.
I'm using Repetier Firmware and Slic3r.
By now code is in the before layer change.
Below is a piece of layer change gcode.
If you want to see the first try: [youtu.be]
Thank you very much.

G1 Z0.300 F7800.000
G1 E2.00000 F2400.00000
G1 F1800
G1 X107.573 Y91.309 E2.03080
G1 X107.573 Y90.909 E2.06160
G1 X107.973 Y90.909 E2.09240
G1 X107.973 Y91.249 E2.11859
G1 X107.587 Y91.205 F7800.000
G90 ;absolute positioning
G1 Y200 X200 F10000 ;move bed and extruder
G4 P500 ;wait a little
M340 S2070 P0 R500 ;shutter press
G4 P100 ;wait
M340 S1950 P0 R500 ;shutter release
G4 P3000 ;wait photo
G1 Z0.300 F7800.000 ;I believe z lift
G1 E0.11859 F2400.00000 ;I believe retract (absolute value)
G92 E0 ;I believe this zeroes the extruder value
G1 Z0.700 F7800.000
G1 X107.510 Y120.030 F7800.000
G1 Z0.300 F7800.000
G1 E2.00000 F2400.00000

Edited 2 time(s). Last edit at 11/13/2018 11:00AM by ChicoCyberGoth.
Re: Gcode for retraction (timelapse picture)
November 13, 2018 06:52AM
The hot-end is going to drool once you move it away from the print. If you mount a wire brush on the printer and have the nozzle brush against it as it returns to the print, it will knock the drool off. As a bonus you can use that brush to periodically clean off the nozzle on a long print, even when you aren't making movies.

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Gcode for retraction (timelapse picture)
November 14, 2018 01:26AM
Thanks for your answer, but by now I just want to retract the filament, how can I do this?
There is a way to put filament movement in relative mode?
After that do I need to specify it back to absolute mode? As looks like my slicer uses it absolute mode.
Re: Gcode for retraction (timelapse picture)
November 14, 2018 01:31AM
Depending on your firmware, it's either M83 to put the extruder into relative mode and M82 to put it back to absolute mode, or G91 to put all axes and extruders into relative mode and G90 to put them back into absolute mode.

All modern slicers that I know of give you the choice of using absolute or relative extrusion.

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: Gcode for retraction (timelapse picture)
November 14, 2018 01:35AM
Nice, I found it right now! I think this is a better idea.
Can you help me?
It is a good idea to do this?
There is any problem I can have?
It is better to set Slic3r to use all in relative or do I leave absolute as it looks "more default" then when making the photo I set relative, retract, take the photo, then extrude back and set absolute back?

Thank you.
Re: Gcode for retraction (timelapse picture)
November 14, 2018 10:14AM
Absolute mode is supposed to help with cumulative rounding errors, so I've been told. Personally, I don't know that those errors are really that important to most of us, and with something like this, it probably does not matter at all.

Yes, you should be able to put the extruder into relative mode, retract, take your photo, extrude, then continue.

MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts
Re: Gcode for retraction (timelapse picture)
November 14, 2018 10:28AM
Ok, I will try to set it to relative, retract, take the photo, extrude back, set to absolute again then resume.

Thanks for the help.
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