RE: Is the Nextruder hot end design choice a mistake?
I really appreciate your contribution to this thread. What do you make of the test shown in this video at about 3m50s? the 0.6mm nozzle seems to top out such that the flow limits the speeds yet you seem to be able to push the speeds faster? Materials, temp etc may be the reason.
OK. IMHO this video shows one of two things - this channel's lack of knowledge when it comes to 3D printing or that they are being intentionally disingenuous about the capabilities of the XL.
I am completely unsurprised that they tapped out at 15mm3/s for the 0.4 and 11mm3/s for the 0.6 running PLA at 195C.
If you are going to push up flow rates, then you need to start bumping temps. It's a fundamental basic that the faster you push the printer, the faster you need to melt the plastic.
The XL essentially runs a Volcano hot end. The nozzle just has a stainless straw sticking out the back of it.
The nozzle and heater combo is capable of high flow rates. I found I actually needed to reduce my temps a bit over stock to stop the stringing because the hot end was melting the plastic too much for stock speeds.
But then when I started pushing speeds, I knew I needed to go the other way to keep up, which it did without issue.
RE:
Now that is interesting.
Yep. Running the 5T IS profiles, but the speeds should be the same regardless of the number of tool heads.
The settings I was using are 0.20 SPEED XLIS 0.6, 2 or 3 perimeters, 15% cubic infill, 4 top and 4 bottom layers. But really, as long as you are using the same settings on both nozzle sizes; you should still see big differences.
I get the exact same results as jF. Is there anything you've modified and saved in your profiles? What filament profile are you using? I've attempted to overdrive flows and speeds and can't replicate what you're achieving.
As another stock example, I added the bunny from the shape gallery, 100% scale. On fresh PS 2.7.1, latest configurations, stock XLIS 0.6 and 0.4 profiles, using 15% cubic, 4 top and bottom layers, 2 perimeters, using the 0.20 SPEED print profile:
0.6:
Used Filament: 88.34
Print time: 2h40m
0.4:
Used Filament: 79.57
Print time: 2h33m
Edit: I used the stock Overture PLA filament profile above. Switching to Prusament PLA shaved 3 minutes off the 0.6 (2h37m). 0.4 didn't change.
Edit 2: Switching to Prusament PETG I finally get closer to your results on the bunny:
0.6: 2h37m
0.4: 2h57m
However a 36x36x36 cube still winds up at 0.6 @ 49m and 0.4 @ 38m
RE: Is the Nextruder hot end design choice a mistake?
FYI: I just got my "complete your order" email and it states all XL's come with 0.4 mm nozzles as default now. Then some blabla about how 0.4 mm is better anyway and you can still swap the nozzles easily.
I haven't completed the order, so don't know if it can be changed back to 0.6. I don't care as speed is no concern for me, but probably some people will be pissed. I'll have to think very hard now if I actually still want this printer.
RE: Is the Nextruder hot end design choice a mistake?
Isn't that interesting. You really have to question what's going on at Prusa currently.
RE: Is the Nextruder hot end design choice a mistake?
I'd value your opinion GuyH based on your posts. Would you recommend getting it? I do design & print lots of stuff and would really like multimaterial, but it's only a hobby. I have proper tools to fix most issues, and MMU experience (sadly a lot). I'll need a better printer anyway, the ones I have will soon fall apart.
Seriously torn, because my playtime is always short and I don't want to fiddle too much. Was hoping for another half year delay tbh, until the kinks are ironed out.
RE: Is the Nextruder hot end design choice a mistake?
I think the XL hardware is sound. It's a great platform to print on. The toolchange is fantastic. There were software and firmware issues early on which they have already improved. The print quality is good now. I would buy mine again given the choice, if that helps. Any specific questions, feel free to ask. HTH
I'd value your opinion GuyH based on your posts. Would you recommend getting it? I do design & print lots of stuff and would really like multimaterial, but it's only a hobby. I have proper tools to fix most issues, and MMU experience (sadly a lot). I'll need a better printer anyway, the ones I have will soon fall apart.
Seriously torn, because my playtime is always short and I don't want to fiddle too much. Was hoping for another half year delay tbh, until the kinks are ironed out.
RE: Is the Nextruder hot end design choice a mistake?
prusa is defaulting to .4 on the XL now?? that's interesting. I remember when they were touting the .6 + arachne as the cat's meow. I'll have to go research that now.
RE: Is the Nextruder hot end design choice a mistake?
sure enough, if you go to the order page, it says the provided nozzle is .4 now.
https://www.prusa3d.com/product/original-prusa-xl-3d-printer/
I wonder why the change.
RE:
https://twitter.com/Prusa3D/status/1736783326424232060
Starting today, Monday, December 18th, all XLs are shipped with 0.4mm nozzle (including orders that were finished before this announcement) instead of the 0.6mm version by default. This change is directly connected with the increased print speed. The volumetric flow (the amount of molten plastic pushed through the nozzle) is similar with both the 0.6mm and 0.4mm nozzles. However, the extruded line is thinner with the 0.4mm version, enabling greater detail but requiring more travel of the print head during the print. With the Input Shaper firmware out, we can now push printing speeds higher (accommodate for increased print head movement) and max out the volumetric flow easily. This means the print times are comparable for both 0.4mm and 0.6mm with 0.4mm providing added fine detail with no downsides. We noticed some members of the community already switched to 0.4mm and seemed very happy! Of course, if you want, you are still able to easily replace the 0.4mm nozzle with a different size - it takes only a moment. All XL owners now have a special 30 % discount on nozzles (both brass and obxidian) available during the process of finishing the order, but also all current owners of the XL (with 0.6mm) can use this discount in their new orders.
They've addressed it hear. Seems this thread has merit as they seem to hit that flow rate of the hot end is partly behind the change.
RE: Is the Nextruder hot end design choice a mistake?
Thank you sir! I was getting used to the .6 nozzle on my xl it would be nice to have it consistent with my MK4s
https://twitter.com/Prusa3D/status/1736783326424232060
Starting today, Monday, December 18th, all XLs are shipped with 0.4mm nozzle (including orders that were finished before this announcement) instead of the 0.6mm version by default. This change is directly connected with the increased print speed. The volumetric flow (the amount of molten plastic pushed through the nozzle) is similar with both the 0.6mm and 0.4mm nozzles. However, the extruded line is thinner with the 0.4mm version, enabling greater detail but requiring more travel of the print head during the print. With the Input Shaper firmware out, we can now push printing speeds higher (accommodate for increased print head movement) and max out the volumetric flow easily. This means the print times are comparable for both 0.4mm and 0.6mm with 0.4mm providing added fine detail with no downsides. We noticed some members of the community already switched to 0.4mm and seemed very happy! Of course, if you want, you are still able to easily replace the 0.4mm nozzle with a different size - it takes only a moment. All XL owners now have a special 30 % discount on nozzles (both brass and obxidian) available during the process of finishing the order, but also all current owners of the XL (with 0.6mm) can use this discount in their new orders.
They've addressed it hear. Seems this thread has merit as they seem to hit that flow rate of the hot end is partly behind the change.
RE: Is the Nextruder hot end design choice a mistake?
https://twitter.com/Prusa3D/status/1736783326424232060
They've addressed it hear. Seems this thread has merit as they seem to hit that flow rate of the hot end is partly behind the change.
Well that's the official explanation. But I can't help think the actual reason is all the stringing problems on shipped printers, especially as demonstrated by prominent youtubers, that have made the XL launch look pretty awful to be honest.
I remember when every 3d printing channel and forum was talking about 0.6mm as the next big thing and "0.4mm is dead" and similar hyperbole. And I think in the right circumstances with the right filament that can be true. But in the real world it seems 0.6mm still has too many problems with stringing, retraction, oozing and it wasn't doing Prusa any favours to keep batting for 0.6mm while it was making their flagship printer look bad.
RE: Is the Nextruder hot end design choice a mistake?
FYI: I just got my "complete your order" email and it states all XL's come with 0.4 mm nozzles as default now. Then some blabla about how 0.4 mm is better anyway and you can still swap the nozzles easily.
I haven't completed the order, so don't know if it can be changed back to 0.6. I don't care as speed is no concern for me, but probably some people will be pissed. I'll have to think very hard now if I actually still want this printer.
Without meaning to sound like a fanboy, the XL is a great printer and if your experience is anything like mine you won't be disappointed. The print quality is very good. The build volume is a gamechanger. The toolchanger has rekindled my enthusiasm for multi-filament printing. I honestly can't think of a better printer at this price point. It's not perfect but nothing is and if I could rewind time I would choose the XL again. I did consider several other printers but nothing ticks all the boxes like the XL. No regrets. Minor complaints. Nothing that would change my mind.
My only advice is order the 5 toolhead version. I bought the 2 toolhead and that was a mistake. I'm now waiting for the upgrade-kit to be available in 2024.
RE: Is the Nextruder hot end design choice a mistake?
https://twitter.com/Prusa3D/status/1736783326424232060
They've addressed it hear. Seems this thread has merit as they seem to hit that flow rate of the hot end is partly behind the change.
Well that's the official explanation. But I can't help think the actual reason is all the stringing problems on shipped printers, especially as demonstrated by prominent youtubers, that have made the XL launch look pretty awful to be honest.
I remember when every 3d printing channel and forum was talking about 0.6mm as the next big thing and "0.4mm is dead" and similar hyperbole. And I think in the right circumstances with the right filament that can be true. But in the real world it seems 0.6mm still has too many problems with stringing, retraction, oozing and it wasn't doing Prusa any favours to keep batting for 0.6mm while it was making their flagship printer look bad.
It gotta be related to stringing and just the generally lower quality you are getting with 0.6. Seem wild for them to change this so early after release just because 0.4 got faster with IS, especially when they are slowing down the print speed for 0.6.
0.6 would still be much faster for large print that take the whole bed, so why the change that if it wasn't problematic? There gotta be a two bird one stone kinda thing going on.
Also that discount sound like an apology, like the free nextruder v6 adapter.. They don't even have the obxidian nozzle in stock.
I hope they will still continue to try and get 0.6 better.
RE: Is the Nextruder hot end design choice a mistake?
whatever the reason, I ordered 5 of the .4 nozzle today and I'll be glad it's a bit more consistent with my 2 MK4s. I'm glad with the nextruder that nozzle changes won't be as daunting as they were on the the MK3S. I did it a couple times on the MK3s to have a hardened steel nozzle and 2 out of 3 times I got leaks and it's made me shy about doing nozzle swaps ever since.
RE:
FWIW I’ve run into this exact same volumetric flow issue on my XL. I tune my own printer profiles quite a bit and have found that the printer is severely flow-limited. I print a lot of PETG and have lately been printing some XL-sized parts. I’ve found that the absolute max volumetric flow for acceptable print quality is 17 mm^3/sec, even when bumping temperatures. At 18 mm^3 I start getting sporadic bad adhesion and gaps in my print lines. I agree with @GuyH that the melt path is just too short to really take advantage of the XL’s potential speed.
In fact the reason I stumbled onto this thread was because I was starting to hunt for info on how to mod the Nextruder design to accommodate a longer heat block and melt path. (Anyone have info or ideas here?)
Also, one thought on 0.4 vs 0.6mm nozzles that I almost never see mentioned: you can squish out a fatter line through an 0.4mm nozzle (with some limitations) but you can’t do a thinner line through an 0.6mm nozzle. For example, I routinely print 0.7mm or even 0.8mm wide lines through my 0.4mm nozzles when I want to print quickly. (A great example of this is how the printer squishes out a short ultra-wide line to clear the nozzle head just before printing.) As long as there is another line below it (or mostly below it), the plastic just widens as it’s flattened by the nozzle tip. The only time where this doesn’t work is when bridging… but you can adjust bridging flow width independently in PrusaSlicer. Anyway, I will always bias toward 0.4mm nozzles because of this. The nozzle diameter just isn’t the flow bottleneck.
In theory a single 0.8mm perimeter should be twice as fast as a double 0.4mm perimeter (and as noted above, both can be printed with an 0.4mm nozzle). This ought to do wonders for print speeds, but it doesn’t because you rapidly become flow-limited. It’s easy to see this if you multiply out the print speed x line height x line width. For a large print where tiny details are less relevant, an 0.8mm width x 0.25mm height should be an awesome way to lay plastic quickly. But the math shows this uses 0.2 mm^3 of filament for every linear mm of travel. At 100 mm/sec travel speed, which is well below the XL’s capabilities, this would require 20 mm^3 of filament per second which is too fast for the nextruder to melt.
I’d love to hear thoughts and ideas on this.
edit: typos
RE: Is the Nextruder hot end design choice a mistake?
I got the new nozzles installed. Did a benchy print to test. seems fine. a bit more involved than the MK4 and times 5 extruders but nothing terrible.
RE: Is the Nextruder hot end design choice a mistake?
Great post and exactly why I questioned the design choice by Prusa. As I see it the options to improve flow are a CHT style nozzle or likely a 3rd party solution. Having paid for 5 tools Im not keen to pay again although it’s unlikely I’d need all 5 tools upgrading. I just wish the Prusa design was better.
RE: Is the Nextruder hot end design choice a mistake?
@ipind-3d
Installed all 1T, 2T and 5T profiles on 2.7.0 over my lunch break and they gave me identical time.
I launch PS, create a cube with the default 36mm dimension. Everything else is the default, 15% infill, 0.20mm speed profile, 5 top layers, and 4 bottom layers. 2 perimeters.
All I do is change the profile between 0.4 to 0.6.
0.6 give me a 48m print time.
0.4 give me a 33m print time..On all 3 profiles.
Reducing 0.6 to 1 perimeter only brought the time down to 32m.
Why are you getting vastly different number from this!?
Why is 0.6 that much slower on my side!?
So confused..
I have been looking into this subject & the reason that your tests are getting slower results for the 0.6 is mainly because your cube is so small, at this size the "slow down if layer print time is below" setting (filament settings, cooling) comes into play and, by default this is set to 14s for 0.6 & 10s for 0.4. If I set both to 10s, I get an equal print time of 38m for both nozzle sizes, removing the limit completely results in 27m for the 0.4 & 25m for the 0.6.
Adding a 3rd perimeter for the 0.4, to get the “same” wall thickness adds a further 2 minutes to the 0.4’s print time.
The next difference is that the max print speeds for the 0.6 are, for some reason, set lower than those of the 0.4, upping the speeds for the 0.6 to match those of the 0.4 results in a print time of 25m; the same as before, reason for this is that the maximum volumetric flow rate of 15mm3/s, which is the default set for Prusa PLA has been reached by the 0.6 nozzle, but has not quite been reached by the 0.4 nozzle. The 0.4 is reaching its maximum travel speed or 200mm/s, but the 0.6 is only reaching approximately 140mm/s. To recap, print times at this point are 29m for the 0.4 & 25m for the 0.6.
I am still waiting (not so) patiently for my XL to arrive, but I have been doing some maximum volumetric flow rate (MVFR) testing on my mk4, using this model & method: Extrusion Test Structure by CNC Kitchen | Download free STL model | Printables.com, but I used a 0.2mm layer height, as I thought that this was more representative of real life situations:
With a 0.4 nozzle & Prusa PLA at the default temperature of 220 degrees I could increase the default MVFR of 15mm3/3 to 18mm3/S before the Nextruder started clicking and the print began to fail, at 230 degrees this point was reached @ 20mm3/s and @ 240 degrees it was 22mm3/s. Setting a “safe” MVFR of 21mm3/s for both nozzle sizes (in PS) resulted in the same time of 29m for the 0.4 (it wasn’t using the full default 15mm3/s anyway) and a reduced time of 22m for the 0.6.
I also tested the MVFR of Prusament PETG & Prusament ASA:
With a 0.4 nozzle & the Prusament PETG at the default temperature of 250 degrees I could increase the default MVFR of only 9.5mm3/3 to 27mm3/S before the Nextruder started clicking and the print began to fail, at 260 degrees this point was reached @ 28mm3/s, I didn’t test @ 270 degrees as there was little increase in MVFR @ 260 degrees, the print had completely failed by this point and I couldn’t be bothered to start again with a fresh print.
With a 0.4 nozzle & the Prusament ASA at the default temperature of 260 degrees I could increase the default MVFR of 12mm3/3 to 21mm3/S before the print began to fail (the Nextruder did NOT start clicking) at 270 degrees this point was reached @ 23mm3/s and @ 280 degrees it was 25mm3/s.
So, if we use `PETG at the elevated temperature of 260 degrees and a “safe” MVFR of 27mm3/s for both nozzle sizes (in PS), this results in the same time of 29m for the 0.4 (it wasn’t using the full default 15mm3/s anyway) and a reduced time of 21m for the 0.6. It appears that he 0.6 is not quite using the full 27mm3/s as increasing it further does not reduce the print time further, to achieve this we would need to increase the maximum travel speeds further, which would, of course, decrease the speed of the 0.4’s print time too.
It is quite possible that the MVFR for each material could increase using the 0.6, but I didn’t order a 0.6 nozzle for my mk4, as I was expecting to be getting 5 of them when my XL arrived, but I might do some more tests using a 0.8 nozzle, when I get the time.
Obviously the above is all theoretical, whether or not it would result in prints of acceptable finish & strength, would be subject to testing and personal opinion.
It is also interesting to note that the greatest difference between the default MVFRs and test results is with the PETG, which is what @IPIND 3D has stated that their most used filament is, hence why they consider the Prusa defaults to be so conservative. The margin with PLA is much smaller.
RE: Is the Nextruder hot end design choice a mistake?
Link for the above post: https://www.printables.com/model/342075-extrusion-test-structure sorry, I'm not allowed to edit it in the post or correct the typos as I'm obviously too much of a newbie!
RE: Is the Nextruder hot end design choice a mistake?
I like what I see. Is it too much to ask in your opinion, what’s the biggest 3 changes you can make to speed up the default profiles? Thanks!
I reiterate:
The default profiles for the XL, even the IS ones; are very slow.
The Nextruder will happily run WAY faster with a lot higher volumetric flow rates and still produce amazing prints. I am running way faster than the stock profiles without issue and I have almost zero stringing issues with 0.6 nozzles and I pretty much only print in PETG.
I do use 0.4 nozzle for models with really fine details - mainly small text that is face down in the first 2 layers or very small surface details.
People need to stop pointing to the stock profiles as them being a speed barrier or some sort of limitation and tune their own. There isn't a volumetric flow issue with the 0.6 nozzle.
It will run the 0.6 without any issues at the stock profile speeds for the 0.4. It will actually go much faster without issue.
In an terms of comparing 0.4 to 0.6, do your example, but change the perimiters for the 0.4 to 3 and the 0.6 to 2 so the wall thicknesses are equal.
You must have old profile configs or are not using the 2.7.0 IS profiles?
Even so, I've just gone in and done some of your examples:
36x36x36 box:
Default XL IS 0.4, Default 0.20 SPEED XLIS 0.4, 2 perimeters, 10% cubic infill, 4 top and bottom layers: 51m
Default XL IS 0.6, Default 0.20 SPEED XLIS 0.6 2 perimeters, 10% cubic infill, 4 top and bottom layers: 31m 40% faster
Default XL IS 0.4, Default 0.20 SPEED XLIS 0.4 3 perimeters, 10% cubic infill, 4 top and bottom layers: 52m
Default XL IS 0.6, Default 0.20 SPEED XLIS 0.6 3 perimeters, 10% cubic infill, 4 top and bottom layers: 32m 39% faster
180x180x36 box:
Default XL IS 0.4, Default 0.20 SPEED XLIS 0.4, 2 perimeters, 15% cubic infill, 4 top and bottom layers: 6h54m
Default XL IS 0.6, Default 0.20 SPEED XLIS 0.6, 2 perimeters, 15% cubic infill, 4 top and bottom layers: 5h30m 21% faster
Default XL IS 0.4, Default 0.20 SPEED XLIS 0.4, 3 perimeters, 15% cubic infill, 4 top and bottom layers: 7h7m
Default XL IS 0.6, Default 0.20 SPEED XLIS 0.6, 3 perimeters, 15% cubic infill, 4 top and bottom layers: 5h44m 20% faster
360x360x360 box - which is no issue to get on the bed BTW:
Default XL IS 0.4, Default 0.20 SPEED XLIS 0.4, 2 perimeters, 15% cubic infill, 4 top and bottom layers: 7d23h20m
Default XL IS 0.6, Default 0.20 SPEED XLIS 0.6, 2 perimeters, 15% cubic infill, 4 top and bottom layers: 5d21h6m 17% faster
Default XL IS 0.4, Default 0.20 SPEED XLIS 0.4, 3 perimeters, 15% cubic infill, 4 top and bottom layers: 8d3h24m
Default XL IS 0.6, Default 0.20 SPEED XLIS 0.6, 3 perimeters, 15% cubic infill, 4 top and bottom layers: 6d2h5m 16% faster
Despite the 'slower' print speeds, simple maths wins the day due to the cubic increase resulting from the higher extrusion width x the layer height.
And just for fun, lets run the same settings, but change the 0.6 speeds to match the 0.4 default speeds; which the XL will do without breaking a sweat.
Default XL IS 0.6, Default 0.20 SPEED XLIS 0.6 @ 0.4 speeds, 3 perimeters, 15% cubic infill, 4 top and bottom layers: 5d22h31m 27% faster
No surprises. The 0.6 beats the 0.4 by a mile in every example. Even the 36x36x36 box is 20mins faster.
Nozzle changes take me about 2mins because I have full hotends ready to swap out.
Mini+MK3S+XL 5 Tool