Multi material print speed question  

RE: Multi material print speed question

Yes; if you configure the max volumetric speed of the filament correctly, it will respect that setting.

Far less hassle than tweaking linear speeds manually, once the value is set it's respected regardless of layer height, etc.

Values can be determined by trial and error (e.g. finding the highest linear rate at which you can extrude continuously without clicking and calculating the volume of filament that corresponds to), but good guidelines are usually 11.5 mm³/s for PLA and 8 mm³/s for PETG.

RE: Multi material print speed question

@vintagepc

Thanks, good to know. I should look into figuring out volumetric speed for different materials. 

Is there a general guideline for volumetric speed somewhere? I can take a peek at? 

Thanks

RE: Multi material print speed question

I read from Bob's project  you can set the extrusion width to zero and let the slicer calculate the extrusion width base on the "individual filament (max volumetric speed) override".

"Volumetric speed limits are your best friend when using multiple nozzles. You can set your speeds to your preferred settings and the volumetric limits will throttle when and if necessary. I’ve got all my extrusion widths set to 0 so PrusaSlicer figures them out based on nozzle size. That is working very well, and I’m able to use a single print setting profile across all nozzles except for fine detail work. I’ve got a separate “miniatures” profile for 0.25mm detail work."

I have two additional questions.

Question 1) 

So does this mean if I have Flex filament (with 1.5mm3/s volumetric speed)  and PLA (with 11.5 mm3/s volumetric speed),  I can set the extrusion width to zero, the slicer will auto calculate the appropriate extrusion width setting? 

 Question 2) 

In the Print setting tab, can I set the default print speed to be higher and let individual filament volumetric speed throttle down actual print speed?  (if the answer is yes: then this is pretty cool 🙂 ). 

Thanks in advance. 

RE: Multi material print speed question

Posted by: @hwlin85

I read from Bob's project  you can set the extrusion width to zero and let the slicer calculate the extrusion width base on the "individual filament (max volumetric speed) override".

"Volumetric speed limits are your best friend when using multiple nozzles. You can set your speeds to your preferred settings and the volumetric limits will throttle when and if necessary. I’ve got all my extrusion widths set to 0 so PrusaSlicer figures them out based on nozzle size. That is working very well, and I’m able to use a single print setting profile across all nozzles except for fine detail work. I’ve got a separate “miniatures” profile for 0.25mm detail work."

Ah, I need to clarify that writing a bit:

1. Volumetric rates will remove the need to set speeds artificially low to avoid overrunning the hotend.
2. Setting extrusion widths to 0 direct allow PrusaSlicer/Slic3r calculate appropriate extrusion widths based on the currently set nozzle size.

These work together but are separate settings. I'll try to be more clear in the notes.

I have two additional questions.

Question 1) 

So does this mean if I have Flex filament (with 1.5mm3/s volumetric speed)  and PLA (with 11.5 mm3/s volumetric speed),  I can set the extrusion width to zero, the slicer will auto calculate the appropriate extrusion width setting? 

Yes, although they are not directly related.

1. If you set a 1.5mm^3/s maximum volumetric speed on your filament profile, the slicer will throttle speeds as necessary to keep below this rate of extrusion. You can see this at work in preview mode after slicing. Use the speed option to see what speeds are being used, then adjust MVS and try again. Note that on small parts, there may be little or no difference due to the amount of time it takes to bring the nozzle up to speed and slow it back down (acceleration and jerk). Also notice that small parts are subject to the settings under Filament settings->Cooling->Cooling thresholds which may also slow prints down.
2. If you set any extrusion width to 0, the slicer will calculate appropriate values, correct. I have very good luck with these settings, and I can specify one print profile and use it with a range of nozzle sizes, reducing the number of slicer profiles I have to maintain.

 Question 2) 

In the Print setting tab, can I set the default print speed to be higher and let individual filament volumetric speed throttle down actual print speed?  (if the answer is yes: then this is pretty cool 🙂 ). 

Yes, exactly! Provided you set reasonable MVS values, speeds will be throttled. Again, this has helped reduce the number of profiles I have to maintain as the same print settings (with speeds) work well with a variety of filament types. YMMV of course, but I don't have to do a lot of adjustment when switching filament types. This is the main reason PrusaSlicer remains my preferred slicer.

Also please note that I never got around to mounting my MMU2, so I can't offer any expertise on usage.

RE: Multi material print speed question

@bobstro

Hi Bob, 

Thank you so much for your response 🙂  Much appreciated.