PTFE tube diameter
I keep my filament in dry boxes and use 2mm ID X 4mm OD PTFE teflon tubing to go from the dry box to the extruder. I'm revamping my setup and will be buying new PTFE tubing. Should I stick with a 2mm ID or go with something larger? The 2mm tubing seems to be fine. I've used it for a few years.
RE: PTFE tube diameter
If you can get tubing with 3mm ID you can compare the pull force required to the tubing with 2mm ID. Tubing with 3mm ID requires less force when pulling the filament.
RE: PTFE tube diameter
I bought some 3mm ID x 4mm OD PTFE tubing and it works great.
RE: PTFE tube diameter
I use and tried several ptfe tube diameter and also from different stores.
Manly I use 2.5x4mm for tubes between spool and MMU cause the 3x4 mm is too sensitive to external forces.
I made also the experience that some 2.5x4mm are thighter and some are more loose. it isn`t easy to measure the difference, but you can feel different forces if putting the shaft of a 2.5mm drill into the tube, at some you need really less force and some you really need to push, so I think the tolerance here is +/-0.1mm
I sorted out the thighter 2.5mm, these I only use for "brakeing-sections" to avoid that in some circumstances the autorewinder spool has to much momentum while unloading.
Ago I also used 2,5x4mm between MMU and Nextruder, but here I had recently issues with some filaments. Here was the issue, that friction caused higher force from Nextruder pulley to the filamant, which results in stripped filaments and stopping filament extrusion.
Here I changed now to 3x4mm tube, since that I also havent that issue till now, but the change was done some prints ago...
Greets Thorsten
My Printables models including Nextruder improvements: https://www.printables.com/@ThorstenLach_1801966
RE: PTFE tube diameter
So why not use the 3mm ID tubing in the hot end? I see a lot of dragging along the filament pathway and I was changing out my Einsy case to accommodate a PI Zero and thought it would be time to change out the PTFE tube in my hot end too. But got thinking, why use a 2mm ID when a 3mm might be more serviceable and reduce friction.
RE: PTFE tube diameter
I think a bigger PTFE diameter is okay or even desirable on the pull side to reduce friction, but not on the push side of the filament path (i.e. after the filament has passed the extruder gear), there it is better to have a more constrained path, because otherwise there is risk of tangling the filament, e.g. with flexible filament.