perimeters not closing, creating z-seam gap
I just tried slicing a cube at 0.2 layers speed setting for 0.4mm nozzle - almost 6 hrs
and the same cube at 0.6 layers for 0.8mm nozzle - 3h16m
All using defaults, '0' in most cases. I leave the slicer to handle max flow and slow print speed to suit where necessary. It will only throttle on long passes where there is scope for acceleration.
I read Bobstro's info on nozzles https://projects.ttlexceeded.com/3dprinting_nozzle_sizes.html#hotend-throughput
It generally seems like sound information, but there are still sentences which, I think, might give a false impression of improved print speed by upping the nozzle size: "If you’re printing large functional parts with minimal detail, a finer nozzle won’t gain you anything. You’ll add significant print time with no real gain. A larger nozzle will move a lot more filament in a given amount of time and significantly speed up print times."
It seems like there are fewer clear statements online hedging such claims with max flow as a bottleneck. In fact, I have not read any such clear statements.
From what I've gathered, if you upgraded to a Mosquito Magnum or a Volcano Hotend, then you could indeed make significant time gains with e.g. a 0.8mm nozzle. You could dramatically increase layer height, extrusion width and print speed. You could print the same object twice as fast, with half the detail. But if you don't upgrade the Hotend's max flow (e.g. by using the stock V6 or upgrading to a Revo 6), you are left with half the detail and the same speed with a 0.8mm nozzle. This does not seem to be spelled out anywhere near clearly enough in online sources for users seeking to educate themselves on the subject.
On a 0.4mm nozzle printing PETG, I currently have 0.3mm layer heights, 0.45mm extrusion widths, and 75mm/s speeds (vflow = 9). Everything is printing perfectly. I think I could probably fine tune this to increase flow/ print speed even more without encountering print issues related to max flow. Given that a 0.4mm nozzle can reach max flow on a V6/ Revo 6 Hotend, the speed gains from a nozzle upgrade are non-existent.
Since a 0.4mm nozzle can hit the max flow capacity on Prusa's MK3S+ Hotend, there is no print speed advantage whatsoever for any user when increasing their nozzle size on a standard MK3S+. This needs to be spelled out more clearly in all online literature pertaining to nozzle sizes.
I didn't catch your reply before for some reason.
Maybe I'm missing something, but for now it seems to me that the default settings aren't pushing the Hotend close enough to max flow at 0.4mm nozzle size. If you're printing PETG, try this out on a 0.4mm nozzle: 0.3mm layer height, 0.45mm extrusion width, 75mm/s print speed for all movements. You might also want to try 50mm/s retraction and 25mm/s deretraction speeds. Compare that with the stock 0.8mm slicer options.
It might just be that the slicer defaults aren't optimising well enough for max flow.
RE: perimeters not closing, creating z-seam gap
*my vflow is set at 10.125, not 9 on current settings
RE: perimeters not closing, creating z-seam gap
I mean, isn't it just a logical thing? If vflow limit is a simple function (layer height * extrusion width * speed) then this is an iron law that a nozzle size isn't going to dramatically alter. If, hypothetically, the max flow were higher on the V6, then yeah, I guess a 0.4mm nozzle might not be able to take full advantage of this, because once you've pushed extrusion width and layer height to the max, there's only so fast you can push the machine's speed before encountering mechanical limitations. In such a case, a larger nozzle size could help speed things up. This would be the case (from what I can gather) with a Hotend upgrade to a E3D Volcano or to a Mosquito Magnum, for example. However, this is not the case for anybody with a V6 or a Revo 6.
You do realise that most of the time the printer runs nowhere near max flow?
On small parts, on fiddly detail and on tight curves the flow will be much less. It's only where the head can take a long, straight path that it approaches the limits.
So: Yes, with big, boring parts there is relatively little advantage, but with the average print you can make appreciable time savings.
I might be missing something still. But wouldn't this depend on your print speed settings? If you make it so the print speed is consistent so you're always pushing to max flow, then you get the fastest prints the Hotend is capable of, no?
Even accepting your point, insofar as a print is fiddly, then it's precisely the sort of print where you will notice the decreased detail from a larger nozzle.
My point is that this doesn't seem to be spelled out in online sources. Quite the opposite in fact.
Take the Revo 6. What's the point of switching out to a larger nozzle with ease? If it's to avoid clogs with exotic filaments, then I guess these customers are few and far between given they only had basic brass nozzles available for many months. Those who just want a bit of a tensile strength bump are probably not too common either. Probably, most want a print speed bump. But the max flow means you could simply achieve this by tinkering with your slicer.
wouldn't this depend on your print speed settings?
If you make it so the print speed is consistent
Hard to do unless you slow way down. Much of the slicer's job is managing acceleration.
If it's to avoid clogs with exotic filaments, then I guess these customers are few and far between given they only had basic brass nozzles available for many months
A lot of exotics. especially the softer fills, are printable with brass.
In my attempts to save time by doubling the nozzle size, I have found max flow to be a bottleneck. This is despite not having read anything about max flow as a speed bottleneck when increasing nozzle size. I think it's worth highlighting this bottleneck potential for anyone considering an upgrade or nozzle swap. If the Revo 6 bumped up max flow a little (instead of reducing it), then the ability to easily increase nozzle size would be infinitely more useful from a speed perspective.
Max flow is typically not reported as a bottleneck in the online information that consumers are likely to consult when considering nozzle swaps. I provided a few examples where the impression is given that you can save huge chunks of time by increasing the nozzle size, when most of the difference could in fact be made up through simple adjustments to the Slicer settings.