Nozzle size - what is best starting out for Jhead ?

I have been away from the forum for over a year. I had done quite a lot of research at the time, but am now quite out of date.

I have the plastic for a Prusa V2 with Hyena bolt and Greg's Wade Guilder. I also have LM8UU linear bearing plus GT2 belts and Pulleys.

Initially I am not using a heated bed and will just print smaller objects - meaning single Prusa sized parts - because I want to build a smaller reprap with a simpler design and using 6mm rods and bars.

Initially my steppers will be Nema 17 77oz/in although later I expect to try cheaper Nema 17 35oz/in.

I am going to buy a J-Head.....

I think that 3mm ABS may be best to start with (rather than PLA or 1.75mm). Is this considered the best starting point?

What nozzle hole should I get (0.35mm, 0.4mm or 0.5mm) ? Would one of these sizes also work for 1.75mm filament too?

While I am asking, previously I played with Blender. I notice a lot of designs appear to be in OpenSCAD. Is this now the preferred design software? And what is the preferred slicer program?

I believe all those size works well with 1.75 filament. Few people had tried to converted a 3mm J Head for 1.75mm filament though. For J Head you can't just swap the nozzle with the barrel because they are just one piece - Though, if I remember correctly, someone reported on the wiki that replacing the PTFE tube with a smaller inner diameter works.

Slicer: Slic3r is gaining popularity, there is a just 2 pages of settings, and most of the time it's good enough. However, skeinforge is still the pro player in the area, besides a lot of tweaking knobs, I heave heard that slic3r sometimes slice thing incorrectly.

Go for a .35 or a .4 and 1.75mm filament as most are converting over to it for various reasons.

I use, and am comfortable, with Cinema4D but I still can't see how blender, or c4d, or Maya, or w/e 3d app, can do the exact measurements like Autocad, et. al., can. If I could stick with my C4D, or you Blender, that helps from have to relearn everything that you are comfortable with but, as I said, I have no idea how to input my exact dimensions which a 3d printer or CNC needs.

So what are the advantages of 1.75mm filament. Presumably, the smaller nozzle gives better prints but slower. Is there any other advantage?
I note the 1.75mm filament is more expensive.

BTW Does anyone have any idea how much a Prusa V2 uses (kg/lbs or meters)?

IMHO the 1,75mm filament does not give you extra resolution this is done by nozzle diameter.

the only advantage i can think of is nozzle pressure with 3mm thick filament you will need more presure true a smaller nozzle size, next to that is offcourse the speed that is needed in your extruder, i can imagin that at some point you are at the lowest point of good extrusion and printing with for ex. a 0.1mm nozzle is below that. its all about volume

and how much does a prusa use, not more then any other printer. you have to think in volume. your object has a specified volume thats the amount of filament u need. most prints single objects are from 0,30-1m for smaller objects to 1-4 to mid and above that for big objects. but its give or take a little. Pronterface gives you an estimate when you load a Gcode for an object

Yes use a small nozzle if you want to make small detailed parts and a big nozzle if you want to make large parts in a reasonable time.

The only advantage of 1.75mm filament I can see is you can do away with the 3:1 gearing most extruders have, or keep it and use a smaller light motor. It might be possible to melt it faster as there is less distance for the heat to travel to the centre. So for the same volume melt chamber it could be longer and thinner. 3mm is usually cheaper as it takes less machine time to make.

The Prusa parts are about 450g depending on infill density, plastic, etc.

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[www.hydraraptor.blogspot.com]

Supposedly it is for speed of melting since there isn't as much mass to melt and the fact that you can have a lighter stepper motor. There must be a reason that all of the named machines are moving over to 1.75mm but all of the reasons I don't know.

Found this by accident: [forums.reprap.org]

Edited 1 time(s). Last edit at 07/21/2012 07:01AM by Dark Alchemist.

cluso99 Wrote:
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> Initially I am not using a heated bed ........
> I think that 3mm ABS may be best to start with.......
>.......

I was frustrated with ABS until I added the heated bed.

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Thingiverse ID Alan1279

I suggest staring out with 3mm (cheaper, no difference from 1.75mm if you use a gregstuder or similar) and PLA (since you don't have a heated bed) with 0.5mm nozzle (simpler to get good prints with a larger nozzle to begin with).

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