Ultimaker Filament Diameter

[drisec 0]

Ultimaker's new Factor 4 model continues to use 2.85 mm filament. What is the rationale for this choice, aside from maintaining compatibility with the existing Ultimaker ecosystem, such as print cores interchangeability and their material portfolio?

 

Moreover the Method line uses 1.75 mm filament.

 

Considering that 1.75 mm filament allows for finer control, potentially better surface finishes and access to even more materials, what advantages does sticking with 2.85 mm offer?

[nallath 1,125]

I'm not directly someone involved with the material and hardware development, but I can tell you the rationale that i got from them.

Control really isn't an issue. We actually ran into the inverse; when working with 1.75 we had more issues with the speed at which we had to move the filament, especially if you really want to push the upper envelope. I don't quite see how the diameter would influence the surface finish that much though (if at all!). At the end of the line, it's still extruded from pretty much the same nozzle.

As far as materials that we directly support via the marketplace, I honestly don't think that there is a printer manufacturer that supports quite as many as we do. So although technically true, it feels a bit more like a theoretical differentiator.

When it comes to advantages, you listed most of them, but forgot a fairly important one; We already have a ton of experience with 2.85. So although it's possible to change, it would mean quite a bit of extra R&D work that we now didn't have to do. The 2.85mm also makes it a whole lot easier to print extremely flexible materials.

[pkuiper 2]

2.85mm allows you to better print flexible materials because it does not buckles as fast as 1.75mm (causing jams or print failures).  A downside is that the minimum radius of the Bowden needs to be larger to prevent rigid materials to break. So we need some more headspace above our printheads (less compact). 

 

2.85mm melts just as fast as 1.75mm for a given flowrate so there is no difference in maximum flow rate. 

2.85mm oozes less because it is easier for the material or gass to move upwards (bigger diameter).
 

Material suppliers do not mind making 2.85mm. It requires less material to spool up, which is cheaper. Also the flow is more accurate because a diameter variation of 50um on a diameter of 1.75mm gives a much worse flow error than on a 2.85mm filament. And like Jaime said, we support a very large selection of materials.