Prusa slicer filament diameter settings, plus feed tube inner diameter.
Couple of questions for the technical members.
Question 1 If for example the filament I am using measures 1.75 mm nominal diameter, then if I set this number to 1.77 mm diameter in the filament parameters would this reduce the stringing.
I am thinking that the firmware would supply less filament to the nozzle through the firmware mathematics therefore possibly less stringing.
I currently use the filament retract parameters as well.
Question 2 If the PTFE tube inner diameter was increased to 2.5 mm dia from the plus 1.75 mm dia nominal, would this not reduce the drag of the filament from the spool and also assist in the complete filament retraction during for example a spool exchange "colour change" , currently when I am printing with carbon impregnated PLA I am having difficulty to fully pull out the filament due to a hardened ball of plastic on the very end. This ball is large enough not to pull through the nominal 1.75 mm inner dia tube and gets stuck.
Thanks
John
Spain
RE:
1 - If you set in the slicer settings a nominal diameter of 1,77mm, but the filament is actually 1.75mm, the software adjusts the length of filament extruded to compensate for that supposed bigger diameter, as you guessed. As a result, you’ll get underextrusion. That doesn’t means less stringing per se, but could help a bit to mitigate dropping overhangs, blobs and other cosmetic imperfections.
2 - Teflon tubes located in the extruder/hotend assembly have an internal diameter of 2mm ( and so it’s the heatbreak in most cases). If those tubes were exactly 1,75mm. the filament couldn’t pass through, much more so with thicker filaments a bit out of specifications.
Instead, teflon tubing for conveying filament from the spool to the entry of the extruder have almost always 3mm. of internal diameter, to reduce drag.
RE: Prusa slicer filament diameter settings, plus feed tube inner diameter.
Hi Arthur,
I understand more of some of the filament diameter setting logic, thanks.
I did not realise that the firmware adjust filament length based on filament dia.
So as the good book say´s "the cup runs over". come what may.
My direction of thinking was that a miniscule change in dia to a larger number would decrease the pressure at the cup before entering for example a 0.4 mm dia nozzle.
My internet searches for 4,0 mm dia O/D 3.0 mm dia I/D PTFE tube, then I have drawn a blank.
Thinking 3,0 mm I/D. IE a wall thickness of 0.5 mm would IMHO be very thin and possibly the Bowden fittings would compress more onto
the 4,0 mm O/D and make them impossible to extract of the tube. Your comments and a link to where to purchase the PTFE would be appreciated.
John
Spain.
RE: Prusa slicer filament diameter settings, plus feed tube inner diameter.
I use this tubing. Works great.
https://www.amazon.com/dp/B07B8CT1YH?psc=1&ref=ppx_yo2ov_dt_b_product_details
RE: Prusa slicer filament diameter settings, plus feed tube inner diameter.
fabnavigator
👍 THANKS
ordered
John
Spain
RE: Prusa slicer filament diameter settings, plus feed tube inner diameter.
From my perspective is your idea to change the filament diameter due to stinging is the wrong approach.
If you face stringing you should first check your temperatures. If you face stringing they are usualy to high. Use a temperature tower to evaluate the ideal temperature for your filament. If this does not solve the issue in total, you can check and adapt the retraction settings.
RE: Prusa slicer filament diameter settings, plus feed tube inner diameter.
Changing the filament diameter in the slicer is essentially the same thing as changing the flow ratio. It just increases or reduces the volume output of the extruder for a given print speed. The flow ratio is a percentage so it’s easier to use.
However, I agree with the other poster that this will not help stringing. Lower extrusion temperature and changing retraction speed and distance are you best bets for reducing stringing. Drying your filament is also important.