Filament diameter?

I'm new to 3D printing and am currently trying to decide on the components for my first printer - and have another question.

I see much discussion about 3mm and 1.75mm filament and direct and sleeved hot ends but I've not been able to find reference material that helps me understand why one is chosen over another. So why should one choose a 3mm over a 1.75mm filament (or vice versa)?

Intuitively it feels like 3mm for high feed, lower resolution and 1.75mm for slower feed / better resolution but surely it can't be that simple, can it?

Thanks.

Richard

My understanding is that 1.75mm allows a printer manufacturer to make the machine simpler and cheaper because they can use smaller/ungeared steppers whereas 3mm filament works best with a geared stepper.

So 1.75mm is best for a cheaper 3D printer and 3mm is best for cheaper consumables. I have tried cheap imported 1.75mm filament that makes it more affordable but you pretty much get what you pay for and if you buy cheap, be prepared to live with plenty of nozzle blockage issues.

I found this on the local suppliers website:

http://diamondage.co.nz/help/faq/#FAQ-11

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My Prusa Mendel i2 inspired Repstrap with welded steel frame: [youtu.be]
And my Smartrap derived Briefcase 3D printer: [youtu.be]

resolution is function of the extruder hotend nozzle. independant of filament width.

1.75mm is more fexable, as in it doesnt fight with the machine when trying to reposition the extruder. Good for bowden tubes and deltas and require less force so works better with direct drive extruders.
3mm works fine on cartisian bots and larger deltas, but generaly you do need a geared extruder of some sort (direct drives for 3mm is mostly marketing.)


re price, as long as you not in a backwards country like myself (and n.glasson) are, then the price is about the same.. For us they try and charge by the meter, so 1.75 is ~3 * the price of 3mm by volume.

Some specilty filament like ninja flex 3mm is reportedly easyer, its doesnt squirm as much

Some are trying to say that 3mm is dead, like beta max tapes... but it is still very popular over here.

Basicaly you chose based on avalabilty and cost in your area, both have advantages and disadvantages.