3mm vs 1.75mm ?
If you were building a Kossel Delta printer from scratch, would you go with 3mm or 1.75mm filament ?
3mm vs 1.75mm ?
I have a printrbot plus with a 3mm nozzle, no complaints. I’m also pretty sure I could load it with 1.75mm filament if needed, whereas it wouldn’t be possible otherwise.
Maybe somebody else who has experience with both might be able to give you a more conclusive answer, but from my experience 3mm is satisfactory.
I have heard many people recommend against a non geared configuration for 3mm filament. 1.75mm may work but just go with a design such as maker gear or Mendel max 2.0 that has internal metal gears. The trouble is I can’t find a bom for that cold end. The closest I’ve found is the ohmstruder but that just tells you to start with the maker gear plastruder. The pg35l is another common geared stepper but they seem problematic. Let us know what you find!
The hotend is the only thing that restricts you to one size vs another. A 3 mm cold end will usually manage 1.75 just fine unless your hot end sucks. Many hotends now allow you to switch out the PTFE also so the choice doesn’t even matter. The latest J-head for example allows this.
As for the general effect of 3mm vs 1.75, 3mm is cheaper, easier to extrude for large nozzle sizes and less sensitive to thickness variation. It’s also more common I think. 1.75 is more expensive, easier to extrude for smaller nozzle sizes, quite sensitive to diameter variation, but if you get past all that more accurate for fine details.
Another small point to consider is that if you plan on making your own filament, 1.75mm filament will have a slightly more consistent width than 3mm
As I understand it, and I could be full of it fwiw, the only reason to use 1.75 is if you have a bowden tube design. Basically the greater surface area on 3mm generates too much friction in the tube. If you dont have the bowden tube then you probably have no reason to worry about it.
With some slicing skills you can do quite a bit of detail with .35 tip and .1 layers with 3mm .