Automated method from CNC Kitchen to evalute the maximum volumetric speed.  

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Interestingly, the work here can maybe be leveraged to other printers also.  I just set up an Ender 5 Plus (purely because it has a far larger build plate than anything Prusa sells), and because the Creality slicer is so primitive, I used PrusaSlicer v2.3 and tried having the Ender run the same gcode as if it were a Prusa i3 MK3.  Voila, the benchy test print came out perfectly.  I thought for sure it would come out worse, but if anything, it may have come out better.  Quite a surprise.  Mind you, this is fresh, out-of-the-box Ender that I had just assembled, with no changes other than adjusting the correct z-height for the first layer of the print.  The hardware itself, aside from also being a cartesian xyz printer,  is completely different.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Posted by: @dimprov

[...]  On the one hand, an MVS limit doesn't come into play much on visible surfaces like outer perimeters and top surfaces because their speeds have been limited to make them look better.  So, in practice, MVS is only of relevance to printed elements that  aren't visible.

Or on prints where appearance isn't of paramount importance. For the PPE prints, I was OK with a rough appearance so long as the print was solid and didn't require extensive post-processing to get it ready to ship. In that situation, external perimeter speeds were the same as the others. I think of MVS as setting an upper limit, not to be exceeded limit. It's very handy when using common print setting profiles across a range of nozzle sizes.

Yet it seems that you two and maybe Stefan are saying that an MVS which corresponds to an underextrusion of maybe 5-10% is what you're using when setting MVS in the Prusa Slicer.  I'm comfortable with that, but why not set an even more aggressive number?  Since it likely wouldn't be visible, is it purely for structural integrity reasons?  

I haven't measured in a way that would identify such under-extrusion, but it makes sense. I'm just stating that it's reasonable for my case since:

1. I'm just trying to identify the maximum throughput at which I can push filament without extruder problems.
2. In most cases, I end up using a significantly lower MVS value for print quality purposes, so high precision in calculating MVS is not required. I was merely noting that the speeds I tend to use correspond to the "90% or better" values identified by others for actual versus specified quantity extruded. This is more significant (IME) with PLA given the relatively limited range of MVS it works well with.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Posted by: @dimprov

Interestingly, the work here can maybe be leveraged to other printers also.

Oh, absolutely! That's what drove me to the extended testing. I'd previously done some casual testing with my Mk3. When I wanted to produce PPE in quantity, I purchased an Artillery Sidewinder x1 with the Volcano (clone) hotend. Knowing that MVS artificially limited print speeds, I wanted to determine just how much could be pushed through it. I was able to double or triple the default values with no issue, which made a huge impact on print times.

I do think this sort of testing would be much more valuable for users of other printers that ship with lower capacity hotends. The Mk3 with a V6 hotend and 0.4mm nozzle is right at the edge of needing to care. I follow a lot of 3D printing discussions, and "speed" seems to be a black art for a lot of users. They encounter problems, slow down, and decide throttling speeds blindly is the answer. In reality, they are using hotends that are rated for closer to 6.5mm^3/s with a 0.4mm nozzle and PLA. If they understood the significance of MVS, they'd likely never use a slicer that didn't use it and would likely get faster prints as a result. I (and others) have tried to make this point, but get a lot of push back from the "experts" who swear magic profiles are the answer, so I don't bother often.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

BTW, I used Tom Sanlanderer's method for adapting PrusaSlicer to other printers.  Tom youtubed about it a couple of days ago. 

Tom said he put together the video at Prusa's request, so therefore it should be completely copacetic to talk about it on this forum.  

It's very nice to consolidate by using PrusaSlicer in a cross-platform manner like this.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Do either of you have a good quality print profile (or equivalent settings) for a 0.8mm nozzle for PETG and/or PLA?  I've been reluctant to step-up to a 0.8mm nozzle for only one reason: not wanting to start from scratch.  It's strange that PrusaSlicer still doesn't come with tuned profiles for anything larger than 0.6mm.  There are still many print settings that I'm unfamiliar with, and now just isn't the right time for me to tackle them all.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

I've got an older working set of profiles here that includes a 0.8mm nozzle setup. I've received good feedback from others that have tried them. I haven't fully updated my printer profiles for PrusaSlicer 2.3's new physical printer approach yet, and some niceties like the print bed image require a couple of manual steps. Let me know if you're after something specific.

I'm curious to see what sort of MVS you get out of a stock Ender 5 hotend. Please update when you get a chance to test!

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Posted by: @bobstro

I'm curious to see what sort of MVS you get out of a stock Ender 5 hotend. Please update when you get a chance to test!

Sure thing.  I'd run it now, but from what others have said the stepper driver currents may need increasing, which might change the results, so I'll look into that first.

I hope to be upgrading the Ender 5+ soon, probably to a direct drive bondtech BMG plus the high flow Phaetus Dragon I had purchased recently (originally intending it for the Prusa i3 MK3).  There's an interesting rant (( https://www.thingiverse.com/thing:3816051) by the speedrive author that direct drive is faster than bowden tubes, despite the extra mass of direct drive, because bowden tubes don't adequately support printing hard turns.  As an example, he notes that the Prusa generally runs faster.  Also, bondtech advertises on its website that the BMG upgrade alone can enable you to print twice as fast.

That said, I'd much prefer to have a dyzend extruder and hotend.  It allows for tool-less change of the hotend in mere seconds!  Not sure if I can find an adapter to fit it to the ender 5+, but if so, it will be very tempting.  It also offers a 5x torque multiplier compared to the BMG's 3x.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

OK, I tried running one of the file's in ron's volumetricspeed.zip from the OP, but it wasn't producing nice coils but instead filament everywhere.  I think the problem is that the heatsink fan on the Ender 5+ leaks out a lot of air near the nozzle, and so it was cooling off the filament too quickly.  Hence, this test will have to wait until after I upgrade the printhead with a different fan arrangement.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

@dimprov

Gresat video.  I have a new BIQU BX on the way and this will be very helpful starting the settings.  

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

I was attempting to recreate the print setting from the dyzend article that I referenced earlier in this thread, which used a 0.4mm nozzle to print at a layer height of 0.5mm and a line width of 1.5mm:

but PruserSlicer v2.3 (PS) wouldn't allow line widths that wide or layer heights that tall.  😥  The maximum PS would allow was 1.2mm wide and 0.4mm tall.   Aside from a small number of big zits, the 1.2mm and 0.4mm limits actually worked out OK.  Maybe longer retractions will help with the zits?  The reduction in total print time is enormous.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Posted by: @dimprov

I was attempting to recreate the print setting from the dyzend article that I referenced earlier in this thread, which used a 0.4mm nozzle to print at a layer height of 0.5mm and a line width of 1.5mm:

You can certainly print wider extrusions with a smaller nozzle. If you stick with decent nozzles with the neck around the opening roughly double the opening size (E3D, P3-d, TriangleLab - The B dimension in the E3D drawings), results are surprisingly good up to ~200% of the nozzle size. Go beyond the B dimension and you may see distortion as the filament pushes up around the nozzle, just asking to snag the nozzle on the next pass.

I've inadvertently printed something sliced for a 0.4mm nozzle with a 0.25mm nozzle mounted and was surprised how well it came out. As you noted, going a bit wider is a handy "cheat" for speed. It also yields somewhat sharper corners. MVS still applies though, so you will want to set it according to what you measure for that extruder, hotend, nozzle, and filament combination for best results. 

I do find, though, that the layer heights really affect inter-layer adhesion if I push much beyond the "80% of nozzle size" golden rule. I am cursiou about the results described in the Dyze article. I suppose if you go super-wide and super-high, it might work out since that maintains the oval extrusion shape and thus contact with adjacent layers. But then again, why not just mount a larger nozzle and get less back pressure to start with? With the smaller nozzle, you're still constrained by MVS (well, the effective MVS of your extruder, filament, hotend, and nozzle combination).

I think this is all underscoring the importance of understanding and measuring throughput to determine a reasonable MVS setting.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

@bobstro

I can think of one advantage of doing it this way, which is that you aren't trapped with a wide line width when doing non-solid infils.  With a 0.4mm nozzle, I have my non-solid infil width dialed down to 0.45mm and support material down to 0.35mm (both of which are the PS defaults for those types).  But if I were using, say, a 1.0mm nozzle those things would be very thick, and the supports would be hard to detach.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

It's an interesting idea with a lot of flexibility. I have run into a few situations where I wanted thicker external walls for speed, but wanted to print finer detail than a larger nozzle would allow. The "cheat" of using up to 200% extrusion widths worked quite well. The part I'm not sold on is going over 80% of nozzle size for layer heights. Perhaps 80% or some lower percentage of extrusion width is a good compromise.

I'm increasingly less convinced that 0.4mm is an ideal nozzle size. I seem to mount either a 0.25mm or 0.6mm lately.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

@bobstro

Is there any way to have PS vary the MVS values depending on the z-height?  It would be nice if I could create an MVS tower, similar in concept to a temperature tower except that the change in MVS values occurs as a function of z-height during slicing rather than run time.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

The OP's method is probably the gold standard, but in terms of quick and easier, how about this?  In PS set the MVS high enough that you're sure to get extruder stepper skipping on a test print.  Then dial-back the real-time speed using the control panel.  Start the print (probably a long, narrow, hollow rectangle would be best), let it go for a few layers, then restore some of the speed, let it go for a few layers, restore more print speed, and so on, until you reach the point where the extruder starts skipping.  Then, review the print and see which layer section you like the best and note what the speed reduction factor was when it was printing.  Based on that, revise the MVS in the slicer, restore real-time speed to 100%, and from there you should be good to go.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

@bobstro

Since you asked, I now have the Ender 5 Plus pumping out PLA prints at 20mm^3 no problem using everything stock but with a plated 0.8mm nozzle and a Capricorn bowden tube.  Presently it's able to complete the same print about 6x faster than when I first set it up using everything stock with just a brass 0.4mm nozzle and all default settings, so I count that as a vast improvement, with probably more to come.  I haven't even tested the limits of this new nozzle yet with PLA, let alone PETG.  😎 

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Posted by: @dimprov

Is there any way to have PS vary the MVS values depending on the z-height?  It would be nice if I could create an MVS tower, similar in concept to a temperature tower except that the change in MVS values occurs as a function of z-height during slicing rather than run time.

I don't think there's a way to do this in PrusaSlicer currently. It's an interesting idea for a slicer setting for modifiers that could.

Again though, the procedure of just extruding directly is about as simple as you can get and I can finish the procedure within a few minutes. Setting up a tower would take longer and you'd still be subject to slicer "helpful feature" interference that you'd have to carefully work around (e.g. minimum print times, different speeds, Linear Advance, etc.).

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Posted by: @dimprov

The OP's method is probably the gold standard, but in terms of quick and easier, how about this?  

For a filament manufacturer, that level of complexity is probably worthwhile.

In PS set the MVS high enough that you're sure to get extruder stepper skipping on a test print.  Then dial-back the real-time speed using the control panel.  Start the print (probably a long, narrow, hollow rectangle would be best), let it go for a few layers, then restore some of the speed, let it go for a few layers, restore more print speed, and so on, until you reach the point where the extruder starts skipping.

In theory, this could work, but:

• It's slow and cumbersome compared to simply extruding filament at different speeds with gcode commands.
• Using a slicer introduces variables within the sliced code. Different feature speeds, enabling/disabling Linear Advance, minimum layer print times, extrusion adjustments under the hood, and other factors might affect results.

I wrestled with a lot of these same issues early on in the process of figuring this out for myself. I finally found some cira-2014 posts on the "old ways" before we had as much useful information to stand on and developed an understanding of how they figured these things out before it was all common knowledge. 

  Then, review the print and see which layer section you like the best and note what the speed reduction factor was when it was printing.  Based on that, revise the MVS in the slicer, restore real-time speed to 100%, and from there you should be good to go.

I'm more inclined to figure out a realistic maximum MVS setting to start with and use that as the starting point for gradually adjusting speeds etc. to get the best results. I did generate some speed testing towers a while back that I used for fine-tuning. In general, I found a lot of settings worked well regardless of MVS -- maximum speeds for different features for quality in other words -- and that I could just adjust MVS per filament and leave the rest of the settings the same, knowing MVS would throttle only if and when necessary. Slow worked best for external perimeters. Getting Linear Advance, acceleration, and jerk settings were also important. My maximum print speeds will usually keep things well below MVS for quality reasons unless I'm using large nozzles.

I'm not trying to be discouraging! Just sharing some of what I have worked through previously.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Posted by: @dimprov

Since you asked, I now have the Ender 5 Plus pumping out PLA prints at 20mm^3 no problem using everything stock but with a plated 0.8mm nozzle and a Capricorn bowden tube.  

Mind if I add that as contributed data to my data sheet? I'd really appreciate it if you could test with a 0.4mm nozzle sometime. A LOT of people on various discussion groups have Enders and have no idea what their real MVS is. It would be nice to give them a realistic starting range. I'm topping off at a bit over 23mm^3/s with a standard V6 0.6mm nozzle with PLA. Going with a 0.8mm 3D Solex Matchless nozzle didn't speed it up any beyond that, so I think that's the top end for PLA.

RE: Automated method from CNC Kitchen to evalute the maximum volumetric speed.

Posted by: @bobstro

Posted by: @dimprov

Since you asked, I now have the Ender 5 Plus pumping out PLA prints at 20mm^3 no problem using everything stock but with a plated 0.8mm nozzle and a Capricorn bowden tube.  

Mind if I add that as contributed data to my data sheet? 

Sure.  However, I'm downward revising the number to 18mm^3, based on observations from printing some  different models than before.  It's SUNLU MasterSpool White PLA.  The nozzle is POLISI3D High Temperature Non-Stick Sharp MK8 Plated Copper Nozzle 0.8mm.  Capricorn bowden tube.  Everything else is stock Ender 5 Plus.