Converting to 1.75 mm filament

[aaron 2]

I have been reading a bit and it seems the general consensus is that 1.75 mm is overall better that 3 mm filament. What are your thoughts on making the conversion? What would absolutely need to be changed in order to make it work?

 

[nick-foley 5]

I've been scheming this for a while, too. What are the benefits you're hearing?

I purchased a hotend for 1.75mm, and would also purchase a smaller bowden from McMaster if I find the motive to make the switch.

Ultimately though my 3mm setup is just printing so well that I haven't found significant reasons to change.

 

[jonnybischof 60]

Without knowing any details, I think there may also be a drawback to 1.75mm filament:

If you have flexible material which has trouble going smoothly through the Bowden tube, wouldn't you have even more trouble with 1.75mm filament because the thinner strain is more flabby than the thicker 3mm strain?

 

[msurunner 2]

Here's my opinion on the matter, FWIW. If you are planning on a multiple hotend setup, a 1.75mm filament is better for the fact that the smaller diameter filament/bowden acts as less of a spring force against the positioning system. For a single hotend setup, I would prefer a 3mm setup for the following reasons. There is less surface area to volume on a 3mm, meaning that for x volume of plastic you will receive slightly less friction force to overcome in the bowden tube. It also acts as a slightly larger plunger/ram in the semi-hydraulic system that we essentially create. While I don't have the numbers to back it up, my gut says this would be beneficial with retractions in a properly setup hotend. Third, a 3mm setup offers more surface area for a drive system and acts more like a rod, giving a bit more "control" to the extrusion. Now, I think you can get away with a 3mm dual extruder setup on an UM because the drive system is actually quite stout, but some other systems, such as a Rostock, are not conducive to 3mm multi-extruder setups.

 

[nick-foley 5]

I can also see counterarguments to some of your stated problems with the 1.75mm,too though - Retraction could conceivably be better with 1.75. Since the 1.75 has a higher surface area to volume ratio, it can be melted faster - which means you can get away with a smaller melt chamber in the hotend for identical performance, which may mean you get better retraction and less oozing

On the other hand, since most filament I've seen is spec'd as +/- 0.05 tolerance on the OD regardless of whether it is 1.75 or 3, it stands to reason that 3mm printers could have more accurate control over extrusion since +/- 0.05mm has less of an impact on total extruded volume when using 3mm filament than it does when using 1.75mm filament.

Would be interesting to see side by side tests. I actually do have identical 1.75mm and 3.0mm hotends (Printrbot UBIS) and I've designed and printed a mount for them on the Ultimaker. I just don't have any free time...

 

[aaron 2]

You are correct about the tolerances. The only real drawback I have read (besides here) is the fact that tolerance are more apparent in the product of the print.

 

[coffeecup 1]

Yes, it is interesting to see side by side if 1.75mm filament works better on a Ultimaker.