How does Revo's high-flow nozzle relate to input shaping?
 
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How does Revo's high-flow nozzle relate to input shaping?  

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petesurfer
(@petesurfer)
Eminent Member
How does Revo's high-flow nozzle relate to input shaping?

Hello there. I've just bought the MK3.5 kit to upgrade my Prusa MK3S+, but I haven't installed it yet. I have the Revo 6 hotend in my printer and I 'm waiting for future firmware upgrades and more expert users to test it before installing, as I'm seeing mixed reviews of the upgrade with people that have printers with Revo on it. 

I'm planning on purchasing a steel , ObXidian nozzle, as I would link to start experimenting with abrasive materials, such as Carbon-Fibre filaments, and I need a steel nozzle for that. My doubt is if I should go with the high-flow steel version or the regular steel one, if I'm planing on using the 3.5 upgrade in the futue. How does the increase in speed cause by input shaping relate with the Maximum Volumetric Speed the high-flow nozzle can provide? When comparing normal steel nozzle, vs high-flow steel nozzle,for the 0.4mm nozzle, the MVS goes from 13mm^3/s to 16mm^3/s which doesn't seem much, but with the 0.8mm nozzle, which I'm also plan on buying, it will increase from  17mm^3/s to 28mm^3/s which does seem like a noticeable increase...

My question is, do these increases in Maximum Volumetric Speed add up to the increases in speed caused by input shaping (and a Klipperised board), or do they cancel each other out? I've seen that the downside of the high-flow nozzle is that the nozzles hole is not a simple cilindrical-shaped hole, which makes it more challenging when cleaning out the nozzle when there are clogs, either by using a needle or doing cold-pulls...

 

 

 

This topic was modified 4 months ago by petesurfer
Posted : 17/03/2024 9:19 am
Allen8355
(@allen8355)
Estimable Member
RE: How does Revo's high-flow nozzle relate to input shaping?

There are many factors in print speed, and nozzle flow is only one part. If print speed is limited by one of many factors, then a high flow nozzle will really make no difference. You car could have a 1000hp engine, but if the tires aren't up to it, or the road is too bumpy, then your probably not going much faster.  You can test it out in the slicer. Slice a fine and check the time. Then under filament, change the flow rate to what you want and slice again. Likely the time difference will be small at best.

Posted : 13/06/2024 12:03 am
petesurfer
(@petesurfer)
Eminent Member
Topic starter answered:
RE:

Thank you very much, for you answer @Allen8355. I think I'm going with the normal one then. The main disadvantage I see  is that the high-flow version has a complex inner channel structure (as shown below), which I think can be troublesome with clogs. 

Thanks!

Posted : 14/06/2024 12:36 pm
Antimix
(@antimix)
Reputable Member
RISPONDI: How does Revo's high-flow nozzle relate to input shaping?

Hello,

I had a MK3S+/MMU3 with REVO6 40W and it is now MK3.5/MMU3 with Revo. I am still finishing the tuning of MMU3 with Revo, and I am enough satisfied.

I say enough because:

  • I purchase the Revo 60W heather and installed it on the MK3.5 during the upgrade, just to discover that the 60W is not supported by the firmware. After several weeks of test failures, I had to dismount it and replace again with the 40W version I had removed. Then all worked fine. I am not sure if the current MK3.5 firmware  version supports the 60W, so beware not to install it or the printer will not work (or install, test, and in case of failure be ready to dismount and replace it again 😉 ) I opened a FW issue and spoke with PRUSA, but of course they said that they could not implement all the possible variations of the MKx HW (extruders, nozzles, motors, sensors...) so the device supplier should release the custom FW, or the maker should implement and compile himself based on what it changed on his printer (and break the switch that void the warranty and installs custom FW of course 😎 )  It was just for the long PRUSA/E3D partnership that the REVO 40W was released as supported PRUSA FW.
  • However since I have the Revo (and this happened also when it was MK3S), I am experiencing too often strange clogs.
  • One time the filament was completely blocked in the nozzle, no way to remove or pull it out. I had to cold down and then nicely screw the REVO nozzle and work with a heath gun to remove the filament. The filament was melted and attached in the tube high part (that is supposed to be cold)
  • Another time, the same, but when it was still hot, I applying a strong pull I was able to remove it.
  • Two days ago, it just clogged. No way to purge material. Pressing manually the filament in the nozzle it was like it was blocked. I used a special tool that has a 1.75 steel filament inserted instead of the PLA filament and with a strong pressure I was able to purge the material and clean it. But probing the brass tube with the steel filament I could hear that the walls of the tube were not clean, but had something on the surface, that probably were reducing the tube size, so, I used the steel filament to scratch the PLA residual until I felt that the walls were smooth.
  • I think that using the MMU creates problems to the Revo, because when the printer is performing the rimming of the filament to have a nice arrow, it raises up and down the filament between the molten PLA and the just above air zone, and it may be happen that the still sticky PLA is deposited on the semi cold area that is too cold to melt the PLA but not cold enough to avoid that it attaches at the walls. I think this will happen also to the MK4 with MMU since it seems to me an issue affecting the all metal systems. The original MK3S V6 had PTFE just after the hot metallic zone, while we have now metal.
  • When something starts to go bad, I hear the Extruder gear starting clicking like something is about to break, and there is an evident under extrusion. Of course some minutes later it will clog.
  • I think also that the two above issues may be created by the MMU3 & Buffer tube frictions. I experienced the issue when I was using the standard PRUSA configuration (buffer of the right of the printer with tubes that do a 90° arc curve). I unblocked the extruder, removed the nozzle, and tried to pull the filament manually from the nozzle exit tube and I felt that it requires a very strong force to be able to pull out the filament. Rawly it may be 1 Kg 😓 , but I will attach a dynamometer to see really how much force the poor MK3S motor should support. I tried now to rearrange the spool and tubes in a straight position just behind the printer, avoiding to curve the tubes, and since then, I did not get any jam. Too early to say, but I will see in the coming days.
  • I hope that PRUSA will support soon the 60W version, since it may earn lots of volumetric mm3 due to higher melting capacity, and this is now important with the MK3.5 high speed and IS.

Regards

 

Posted : 23/06/2024 7:16 pm
Allen8355
(@allen8355)
Estimable Member
RE: How does Revo's high-flow nozzle relate to input shaping?

Did you have a look at this: https://github.com/prusa3d/Prusa-Firmware/issues/4451

There is some GCODE for the 60W Revo. I tried the 40W GCODE and it seems to work for mine, at least on my MK2S. 

 

Posted : 23/06/2024 7:34 pm
Allen8355
(@allen8355)
Estimable Member
RE: How does Revo's high-flow nozzle relate to input shaping?

Let me also say, I have 6 printers now, an MK2s, MK3S+, MK4, and 3 Bambu Lab printers, and in the last 4+ years I have never had a clogged nozzle. I fact that you have so many, is a problem. You mention PLA lots, so lets start there. With PLA, assuming your not using glitter PLA or CF PLA, if your at the right temp, its pretty hard to clog a nozzle. But what can happen with PLA is the ambient air can get too hot, or the cooling fan on the hotend maybe isn't strong enough.  This cause the cool side of the hotend to be too hot, so the filament melts instead of pushes. The HF nozzles take a bit more "push" so it can happen more. A 60W heater will NOT help here. And it's debatable for a PLA printer you will ever need this. 

So make sure your cooling fan is working well, and make sure the air is not too hot. If you have an enclosure, open the door. If it's still clogging, then the cool part is too hot, and get that fixed first.

Posted : 23/06/2024 8:59 pm
petesurfer
(@petesurfer)
Eminent Member
Topic starter answered:
RE:

Thank you for such a detailed description of your experience @antimix. I will definitely wait until there's a proven working firmware for the 60W hotend compatible with the Prusa (the MkK3S+, in my case). I'm also quite wary about the need of having to upgrade the PSU unit. I'm not clear if the extra 60W will max out the stock Power Source Unit provided with the printer....

On the other hand, talking about clogs, you've probably already tried it, so please ignore the rest of my message if so, but I've been using cleaning filament (made of Nylon), and it's been an absolute game changer regarding clogs. What I usually do when I have a clog is:

1) wait for the printer to cool down

2) remove the revo nozzle from the hotend

3) Cut the excess filament as close to the nozzle's rim as possible (I'll do this if I'm unable to pull it out without using excessive force and avoiding to heat the nozzle with a torch).

4) Then I reinsert the nozzle, disable stepper motors, and disable load filament function, unscrew the idle screw and heat the hotend to 250-260 degrees, and insert the cleaning filament.

It works really, really well. The only downside is that Nylon is abrasive and it will abrade the brass nozzle I use, but I only use it every 3-4 months when I have a clog, so I would imagine that's not something to worry to much about...

Many thanks!

 

This post was modified 3 weeks ago 3 times by petesurfer
Posted : 24/06/2024 8:36 am
Antimix
(@antimix)
Reputable Member
RE: How does Revo's high-flow nozzle relate to input shaping?
Posted by: @allen8355

Did you have a look at this: https://github.com/prusa3d/Prusa-Firmware/issues/4451

There is some GCODE for the 60W Revo. I tried the 40W GCODE and it seems to work for mine, at least on my MK2S. 

 

The issue was related to the MK3S+ Firmware. Now I am upgraded to the new MK3.5 (and new Buddy board) with the latest FW 6.x.x, and while on the MK3S+ the 60W was supported, now on the MK3.5 the 60W is not supported! PRUSA is uncertain when and if they will release the support of the 60W since the product is not original PRUSA ☹️ 

Posted : 24/06/2024 7:09 pm
Antimix
(@antimix)
Reputable Member
RE: How does Revo's high-flow nozzle relate to input shaping?

@petesurfer I have the cleaning filament, and in this case I forgot to use it 😓 However the issue was that the brass tube of the REVO was blocked few mm after the entering hole, so no filament could be inserted even when the nozzle was set 200°.

As explained, to unclog the nozzle, I used a tool with an 1.75 iron filament, that I inserted instead of the filament. It did enter few mm, and then stopped. But when I applied a strong pressure on the iron filament, the pressure inside the nozzle was so high that it was able to move/melt the block and suddenly all the PLA was ejected by the nozzle, and the nozzle was emptied because the iron filament and the nozzle were like a syringe now. Then I have done an additional cold pull.

I think the issue is the thermal model of the REVO AND  the MMU.

I print PLA at 225° to have a better fast flow of PLA at IS high speed on the MK3.5, but I think that the original PRUSA extruder fan may not be enough to cold the hot metal REVO, also due to the PETG enveloping PRUSA structure of the REVO holder.

So could be that the REVO nozzle reaches around 180° near the top of the nozzle brass tube where it moves to the cooler zone. At this temperature when the MMU is doing the filament ramming to create perfect filament tips some PLA partially melts and attaches to the top hole brass surface, creating a cork that narrows the passage.

The only viable solution I see is print PLA at lower temp (210°) and not to use a MMU! 😨 .

At this temp, at high speed the PLA is melted around 198° due to the fact that there is not enough heat from the 40W cartridge to pass in short time, but it should not raise over the end of the brass tube,and however in normal print nothing should happen. The issue is created by the MMU when it ramming up and down the filament in that area (just over the melting zone).

But those are only assumptions: it they were true, nobody could be able to print PLA over (say) 220° on a REVO with MMU3 without clogging, and I have no proof that this happens to users. May be also they exist "magic" ramming settings specific for the MMU3 and REVO6 in the PrusaSlicer settings that avoid this issue. 🤔 

May be I will need to install a temperature probe on the nozzle to discover the real temp of the brass in that point, and take some Infrared photos.

Installing a 60W could make even things worse, but it may not due to the fact that I could print at 210° at high speed, and the real temperature will be maintained at 210° by the 60W heater.

I will continue to do tests.

Regards

 

Posted : 24/06/2024 8:19 pm
Allen8355
(@allen8355)
Estimable Member
RE: How does Revo's high-flow nozzle relate to input shaping?

Your right. I see PRUSA removed some GCode commands on the new processor. Two steps forward, one back.

Posted : 24/06/2024 9:57 pm
Antimix
(@antimix)
Reputable Member
RE: How does Revo's high-flow nozzle relate to input shaping?

But, as they said "...We supports only PRUSA products" 😉 
So let's see how and if the MMU3 ramming impacts also another ALL METAL EXTRUDER (e.g. MK4 Nextruder) 😀 
Otherwise it could be an issue only for REVO.

Posted : 25/06/2024 10:34 am
Allen8355
(@allen8355)
Estimable Member
RE: How does Revo's high-flow nozzle relate to input shaping?

Prusa has a new printer, the Prusa Pro HT90, which uses as its nozzle, wait for it.....The REVO, making it, "A Prusa Product."

Posted : 26/06/2024 10:07 pm
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