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Is 0.1mm retraction too much?

Posted by nikko4913 
Is 0.1mm retraction too much?
March 09, 2019 08:50AM
Hello.

I have reached a frustrating part of 3D printing this afternoon, and I think I need your help identifying the issue...

I am printing this retraction part from thingiverse: [www.thingiverse.com]

Here is two pictures of two prints:





The first image is of a print where retraction is entirely disabled, and the other image is of a print where retraction is set to 0.1mm at speed 30 mm/s. No other settings were changed.

On the first print the "walls" are completely solid and well-extruded, whereas the walls on the other print look much more porous.

General configuration of printer:

• Material: PLA 1.75mm Innofil3D
• Extruder: Bondtech BMG
• Temperature of bed: 60 celsius
• Temperature of hotend: 210 celsius
• Print speed: 30mm/s
• Slicer: Simplify3D 4.0
• Hotend: E3D Chimera+ fan-cooled (already followed E3D troubleshooting guide)


I have tried a wide range of temperatures ranging from 185 to 220 degrees celsius, but I always run into this problem... I have tried seeing if my "cold block" of the hotend gets warm, but it doesn't. At most, it gets around 40 degrees celsius.

Does anyone have any idea what might be causing this?
Re: Is 0.1mm retraction too much?
March 09, 2019 06:05PM
i would imagine .1 is not too much
Re: Is 0.1mm retraction too much?
March 11, 2019 04:03PM
I use a 3mm retraction on my Chimera, and that works pretty well. When dual printing I also use the draft shield rather than the wipe tower, I get pretty decent results.

DLC


Kits: He3D K200 Kossel, Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head
Scratch: Large bed Cartesian, Linear slide Delta, Maker-Beam XL Micro Delta
Re: Is 0.1mm retraction too much?
March 12, 2019 08:29AM
Normaly 0.1mm would be almost pointless - as MechaBits implies.
If it gives that much difference in the print you probably have another issue.
For example:- The extruder feed rate is not calibrated correctly (steps per mm) and you have compensated by changing the flow rate multiplier. Your 0.1mm retraction then gets converted by the calibration to a different value such as 1mm (factor of 10 out = unlikely but illustrates the issue) and then you under extrude for a while.
Could also be due to 1.75mm filament v 3mm filament in the setting.
Hard to know without any details.
Re: Is 0.1mm retraction too much?
March 12, 2019 11:45AM
I think you have some other problem, such as a partially blocked nozzle, that is coincidental to the change in retraction settings. For a direct extruder, retraction of about 1mm is normal and usually sufficient, but it depends on the nozzle diameter, extruder acceleration and retraction speed settings.

What are the rest of the extruder settings- acceleration, speed of retraction, jerk, etc.?


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Is 0.1mm retraction too much?
March 12, 2019 11:56AM
Quote
the_digital_dentist
I think you have some other problem, such as a partially blocked nozzle, that is coincidental to the change in retraction settings. For a direct extruder, retraction of about 1mm is normal and usually sufficient, but it depends on the nozzle diameter, extruder acceleration and retraction speed settings.

What are the rest of the extruder settings- acceleration, speed of retraction, jerk, etc.?

My 3mm retract example is from a Bowden setup on a Tevo Tarantula. I do not know what you printer configuration is, and I assumed Bowden because if you are using a Chimera, you are dual filament, which "usually" means a Bowden, no matter the config. But not always.

On one of my Bowden printers I did see messes like this that was corrected by changing my retract distance. I started out with a retraction that was too far, which alternately starved and then flooded my print created horrors similar to the OP. Too little retraction should not do more than just increase stringing. However, I have seen oddities with 3D printers that were difficult to explain and correct before...

DLC


Kits: He3D K200 Kossel, Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head
Scratch: Large bed Cartesian, Linear slide Delta, Maker-Beam XL Micro Delta
Re: Is 0.1mm retraction too much?
March 12, 2019 12:33PM
Typical retraction needed is up to 2mm for a non-Bowden extruder. For a 1.75mm Bowden extruder printing PLA, around 2mm plus very roughly 0.8% of the Bowden tube length. If you are using pressure advance and the firmware does it properly (i.e. it starts retracting filament before the end of a printing move when the deceleration, flow rate and pressure advance constant demand it), you should reduce the amount of retraction.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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