[Closed] Changing the form of the printing layers  

RE: Changing the form of the printing layers

The V6 hot end can only melt so much plastic per minute. Are you sure a 1 mm nozzle with whatever width and layer height you are planning is even possible?

RE: Changing the form of the printing layers

Hi Eldord, 

Tim raises a valid point. 
You might need a Volcano hot end, to manage the filament melting  rate that you would need for a 1mm nozzle. the standard V6 heatblock has insufficient length in the melt zone, to handle large nozzles. 

there are modifications to allow Volcano on the Prusa printer range. these can be found on Thingiverse

the items you would need to update include the :-

Nozzle Diameter (Extruder settings under 'Printer Settings')

Extrusion width values (Printer Settings 'Advanced')

Maximum Volumetric override (Filament Settings 'Advanced')

Custom Gcode (Filament Settings, ) this probably needs to be revised to acknowledge new nozzle size

there are probably other settings but I haven't played with them

Compare the differences between the 0.4mm nozzle settings and the 0.6mm nozzle settings in the standard prusa profiles and this should confirm what needs changing, and give you an idea of the magnitude of the changes required!

regards Joan

RE: Changing the form of the printing layers

Posted by: eldord

[...] I want to use the Prusa printer to fill up a 12x4x4 mm space. Precision is not important to me so I want to use a 1mm diameter nozzle to save time. Because the thickness of the material that comes out is greater than what the software recognizes, I want to change the way the head moves along the X and Y axis to support a 1mm thickness. Is there a way to do it?

I have used a 1.00mm nozzle frequently on my Mk3s with the standard E3D V6 hotend. It works just fine, albeit slowly. Don't let that put you off. Speed is an illusion. The 1mm nozzle is at the top end of what works reasonably on this hardware. A 1mm nozzle can still save you time for large parts. Traces are huge, but if you want strong functional parts, they're perfect. Any larger and you definitely see a net loss in terms of time gained. At 12x4x4mm, your part is small enough that you probably won't see much of an improvement, and of course, corners are going to be more rounded with a 1mm nozzle. Do you have a link to the STL you're printing?

What do you mean by "the thickness of the material that comes out is greater than what the software recognizes"? PrusaSlicer has no issue running using a 1.00mm nozzle. You are going to be reduced to very slow speeds (~11mm/s with PLA, 8mm/s with PETG to stay within the maximum volumetric throughput rate of the hotend) but are moving a huge of material as you do so.

I've created notes on configuring PrusaSlicer for use with different nozzle sizes here, and I've got some older profiles you can try out out here. All my notes on using different nozzles can be found here. 

RE: Changing the form of the printing layers

My point was: 12 mm3/s with 1mm nozzle and 0.8mm height is the same volume result as 12mm3/s with a 0.4 mm nozzle and .32 mm height.  Just faster printer movements with the 0.4 mm nozzle - but same volume over time.  Think plumbing where you have a restriction upstream that limits you to 12 gpm; the nozzle at the end of the hose really doesn't matter if either can reach that 12 gpm limit.  

I've printed in excess of 20 mm3/s with a 0.4 nozzle, so the orifice is not a limiting factor. 

RE: Changing the form of the printing layers

Posted by: Tim

My point was: 12 mm3/s with 1mm nozzle and 0.8mm height is the same volume result as 12mm3/s with a 0.4 mm nozzle and .32 mm height.  Just faster printer movements with the 0.4 mm nozzle - but same volume over time. 

It depends on what you're printing. If you can can eliminate the need to print a perimeter, a larger nozzle can be considerably faster. You can also use higher layer heights to eliminate the need for entire layers. This comes at the expense of detail, of course. Larger nozzles will also produce stronger infill (wider extrusions). The size of the part OP mentions is way to small to see much benefit from using a larger nozzle. If you're printing big parts, it will make more of an impact on overall print times.

For example, I've been printing customized shelving inserts for my new cabinet. Here's one printed at the maximum settings for 0.40mm nozzles:

It takes nearly 5 hours at 0.32mm layer height and 0.48mm extrusion width. Using the same layer height with a 1.00mm nozzle:

I've knocked roughly 2 hours off the print at the same height. The gain is in reducing perimeters to be printed. Let the nozzle really show its stuff with 0.80mm layer heights and print times get down to well under 3 hours:

A bit of a boost to times, but you can see that layer heights matter proportionally less than eliminating perimeters. It's all going to depend on what you're printing. But if you want big parts and aren't after detail, I've found nozzles up to 1.00mm work well on the Mk3. Definitely diminishing returns at any size above 1.00mm though.

Hmm. No idea why my screenshots show different resolutions.

I've not had a chance to repeat my MVS testing with the larger nozzles, but they can definitely move a lot more than the smaller sizes. I'll have to try opening up MVS with a 1.00mm nozzle to see what I can get through it reliably. Don't need any more shelving or drawer inserts though...

RE: Changing the form of the printing layers

As the OP said, all that is important is speed. So why slow down perimeters, or even print them at all. Just do solid infill as fast as the VFR will allow.  

I'll concede this test of mine failed to prove my point.  But the result is counter intuitive and may even expose a slicer error. 

What gets me is printing the same volumetric rate isn't equal for these two case, so both aren't really flowing at the 15mm3/s P.Slicer says.

12x4x4 = 192 mm3, and at 15 mm3/s should complete in about 12.8 seconds. So there seems to be a lot of extraneous moves that hinder throughput.

Mystery solved ... seems the 0.4 nozzle never even approaches 15 mm3/s.  Nor does the 1mm nozzle.  On a part this size both are jerk/acceleration limited.  On larger parts the time difference will be much less - but will depend on using larger than recommend extrusion widths for the 0.4 nozzle to ensure the volume limit is met... and in testing found the the "check" for nozzle-width normalcy is a pain.

And I missed changing infill away from Gyroid ...

RE: Changing the form of the printing layers

So it looks like the larger nozzle will print the part in 1/4 the time, no?

I've quit worrying about linear speeds, focusing instead on print times and quality. Depending on the print, different nozzles may be appropriate. What applies to a 28mm miniature isn't going to apply with a large functional part. I like having an array of nozzles to suite different needs. The E3D does fine up to about 1.00mm size. 0.80mm is usually plenty big enough.

RE: Changing the form of the printing layers

Hi Tim

Thanks a lot for your help. Can you please tell me what settings did you used to get the part sliced as the second picture?

RE: Changing the form of the printing layers

Just discovered a nasty "feature" of P.Slicer 2.1.0-alpha: it shows the export folders in the status bar; maybe that was there in v2.0.0, but it will expose a username for Windows users... something to keep in mind when posting screen shots of P.Slicer.

12x4x4-Block.zip

RE: Changing the form of the printing layers

The setup is included in the zip file ... I missed changing infill to 100% rectilinear again ... lol.  But an easy change to make.  Not even sure it's needed though.  And - caveat - no warranty this will even print: it is a simple settings mockup.

RE: Changing the form of the printing layers

Got it

Thanks!