Hi guys. Working on a new printer design. Wondering what your thoughts are on 3mm vs 1.7mm filament. I have watched every youtube video and read every blogpost i can find, but some are 3-6yrs old in a rapidly changing market. I realize you can get nearly the same results with either size with a properly tuned setup. it looks like both sizes are here to stay but i’m not sure.
So my question is, should i design in 3mm or 1.75mm?
backstory:
I am a mechanical engineer. I enjoy designing and building the machine as much as printing itself. I realize i could build one of the already existing designs, but i want the enjoyment of trying something myself (fail or succeed).
current design parameters:
~200x200x200 build volume
bowden
E3D v6 hotend, maybe plated copper heaterblock
linear bearing rails for all axes
gantry style XY with Z moving up and down, similar to bcn3d sigma r17
noctua 40mm fan for e3d
2x 40x10 blower for part cooling
printing of pla->pc. so i guess topping out around 270-300c
Why do you have to design for anything specific? – Design for an E3D hotend and poof - they’re all the same, and you can choose 3mm or 1.7mm. Extruder drive motors are mostly the same.
You need less force (more speed) - compared to 3mm filament - if you use 1.75er. For a ‘bowden’ extruder - i would always use 1.75 mm for <=0.5mm nozzles.
@Marcus_Alexander_Lin in a bowden setup a thicker filament could minimize bending (makes it stiffer) and as the force is applied to a bigger area the compression is equal. But with less movement the compressibility of the material itself would play a bigger role.
I found 3mm is better for specialist filaments, especially flexibles but can be a bit springy and difficult to handle with some non flexible filaments. I always got the impression 3mm was more suited to direct drive and 1.75 more suited to Boden.
@Gerald_Dachs thanks for the tip. this is still early in the design :D. was thinking something more along the lines of the UM3. still a WIP. missing/deleted image from Google+
@Daid_Braam we have a UM3 at work and i get exceptionally dimensionally accurate results with ultimaker PC and PLA/PVA filament which is helpful for functional prototyping machined parts. so, changing to 1.75mm seemed like changing a lot of variables since i will have to source new filament brands. Anyway, ended up getting a 1.75mm v6 hotend. thanks.
@Jonathan_Gourley“… i will have to source new filament brands.” Having several years FFF experience - sourcing filament out of china myself - i can recommend ‘Formfutura’ - you can even get “White Label / Private Label” filament there.
I just switched from 3mm to 1.75mm filament. The biggest pro is that 1.75mm is much more flexible. This is especially nice when you reach the end of a spool and the filament is all curled up. I still have some 3mm filament on spools that is just unprintable.
It’s all a matter of trade-offs. Direct means having more mass on your carriage/effector, which increases ringing or decreases available acceleration, all other things being equal. Setting up your print parameters for with bowden can be a little harder but I don’t feel like I’m missing out.
I would just design for 1.75mm filament just because it’s used more. Generally speaking, exotic materials are easier to find in 1.75mm. Only a handful of companies still make 2.85mm desktop printers, four at last count, but they don’t seem to be going anywhere either.
@Christian_Schulz i’m working on (hopefully) a dynamically stiff machine which will have high mechanical bandwidth. this means stiff structural components and low mass moving masses (i.e. X axis, hotend/fans). the bowden setup allows the mass of the extruder motor, gears, and housing to be mounted in a stationary position at the cost of ‘lag’ and friction when the filament compresses and decompresses in the bowden tube. since i don’t have any specific plans to print flexibles, this should be mostly ok. bowden setup can also have issues with high number of retractions.
