HF Nozzle  

This is another case, like speed settings, where the affect is not intuitive.

Maximum extrusion rates amd maximum speeds can only be acheived where there is a long run of deposition (it takes time to accellerate) that has time to cool between layers (if the underlayer is still molten it cannot support more) but many prints do not meet these requirements.  Unless you are printing large parts there is little to gain from increased throughput.

Cheerio,

RE: HF Nozzle

Thanks Diem!

We are printing big parts, almost a full printing area of the XL. That is why i was expecting faster speed on the long runs…

See picture attached,

Thanks

Not a lot of long runs there 'though you could change the print angle as an experiment. All those rectangular details mean there's not going to be much chance to get up to a speeed where the extra flow will be noticeable.

Cheerio,

RE: HF Nozzle

Most likely I’m preaching in the dessert so to speak, but for what is worth, here’s my five cents on the so called high flow nozzles.

 Guys, think twice (or thrice) before purchasing them. They offer very little flow improvement over a regular nozzle and they have an important drawback.

The capacity of a hotend for supplying molten filament is dictated by the following factors in decreasing order of importance :

1- Power in watts of the heater cartridge.

2- Material of the heater block. Copper being better than aluminum.

3- Material of the nozzle. Stuff of high heat conductive coefficients like brass, copper or TC better than any hardened steel alloy.

4- Efficiency of the heatbreak. the more efficient it is, the better the heat stays inside the heater block.  Mosquito hotends (original or clones) beating clearly other designs like V6, Revo and Prusa nextruder

5- Internal geometry of the nozzle. HF nozzles with several internal paths transmit faster the heat to the filament.

Number 4 and 5 offer only marginal advantages. Number 1 and 2 are the main factors dictating the flow capacity of a hotend.

 Now, the noticeable drawback : All manufactures and vendors of HF nozzles conveniently forget to mention that if you get a clog inside a HF nozzle, it’s much more difficult to fix, than with a regular nozzle. Try a cold pull with one of these and you’ll  see what I mean.

Preaching in the dessert is over.. 😊 

RE: HF Nozzle

Posted this fora similar question on Reddit but helps to have pictures too:

An HF nozzle will only be useful with models and settings that actually get to the point where more volumetric flow is needed and reached.

Even with a 359mm cube: at .2 SPEED settings you're only hitting ~16mm2/s vol flow rate; at .25 SPEED you're hitting ~22.

Change the large cube to a 50x50mm pillar, now even with .25 SPEED you're only hitting ~14 vfs which can be done with a normal nozzle.

So unless you're printing large things with large features, or pushing speeds faster than Prusa's default 'fast' settings, you may not actually get that much out of an HF nozzle. Def more for the types of people who push the envelope, fine tunes their filaments/print settings to match the maximums of their hardware+software, actually make use of the XL's large 360mm bed; not so much for a normal person who relies on default settings and prints multiple small items but on a large bed.

Conversely:

359mm cube: .25 SPEED, HF everything prints in 4d8h24m (~104hrs)(second screenshot in post); .25 HF SPEED Print speeds with "just IS"/"non HF" Printer/Filament settings prints in 6d4h31m (~148hrs)(screenshot below). So I save ~44hrs, or ~30% in a best case, but useless, scenario with a .4HF nozzle.

I'd assume it gets better with the larger nozzles, but it's still very model dependent. Even with a 2000hp supercar, you won't get to places any faster than the beater honda when you're both stuck in the same bumper to bumper traffic and getting caught at all the same stoplights.

RE: HF Nozzle

I don't believe Prusaslicer properly leverages the HF nozzle yet. It alters the nozzle height expectations of the printer, but filament profiles are unrelated. So Filament X has the same Max volumetric flow rate limit for a high flow nozzle as a standard one. 

This is the volumetric flow rates for a standard nozzles, with a nextruder.

https://help.prusa3d.com/article/max-volumetric-speed_127176

Revo Highflow tends to be about 30% faster than a standard nozzle.

You need to increase alter your filaments Max Volumetric Flow presets by 30%

A print takes 5 hours when TPU is set to 2.5mm/s

Boosting that to 3.3mm/s reduced print time to 4 hours

If this solves your issue, give it a thumbs up.

RE: HF Nozzle

I don't believe Prusaslicer properly leverages the HF nozzle yet. It alters the nozzle height expectations of the printer, but filament profiles are unrelated. So Filament X has the same Max volumetric flow rate limit for a high flow nozzle as a standard one. 

You have to make sure you have an HF enabled printer profile loaded if you want to see the HF filament profiles without having to 'show all flag' override.

RE: HF Nozzle

Thanks for that. This really wasn't clear to me.

I've been using MK3s and MK4s for ages, and just added the XL hf, but didn't look if there were new filament presets.

RE: HF Nozzle

Howdy, I'm still having issues with this.

So, due to cost vs benefit, I've only fitted one HF nozzle on extruder 1.

I've created my own printer profile, by taking the HF printer profile, and editing extruder two by untoggling the HF setting.

But when I go to filaments, and select each extruder, they are both pulling the same HF filament profiles with the same volumetric flow rates.

I think I might need to "show all flag" as you suggested, but I don't see how to do this.

RE: HF Nozzle

If I said I 100% understood how PS does their different filterings/dependancies I'd be lying. From the Filaments>Dependancies line it seems like whether it should show up 'green flagged' seems like it's based on the single "HF_NOZZLE" line in Printers>Notes, but removing that line didn't do anything. So I don't know.

Mixing things in PS for the multitool XL is still officially unsupported, but the software is robust enough to let you do it anyway if you figure out how to dance around some things.

The "show all flag" is in the Filaments section.

RE: HF Nozzle

Posted by: @artur5

Most likely I’m preaching in the dessert so to speak, but for what is worth, here’s my five cents on the so called high flow nozzles.

 Guys, think twice (or thrice) before purchasing them. They offer very little flow improvement over a regular nozzle and they have an important drawback.

The capacity of a hotend for supplying molten filament is dictated by the following factors in decreasing order of importance :

1- Power in watts of the heater cartridge.

.....

Preaching in the dessert is over.. 😊 

This persistent myth has been pretty thoroughly debunked.  Please post authoritative-sounding responses when you actually know what you're talking about 🙁

The actual power required to melt the filament is very low.  As in a fraction of watt per additional mm3/sec.  melt/flow tradeoffs are well covered in literature, but for this simple question it's also trivially discoverable from the basic material properties (~~ 100 kJ/kg latent heat of fusion for common plastics, density of perhaps 0.9 to 1.3 g/cm3 for various plastics ==> will give you tenths of a watt for each mm3 per sec melted).  Perhaps a final value a little under 0.5W to melt.  This is significantly lower than the other losses in the system.

if you're not interested the science or engineering behind it, CNCKitchen also has quite accessible data, such as https://www.cnckitchen.com/blog/e3d-revo-high-flow-review, which captures, among other things, an increase of + ~10mm3/sec for an increased load on the heater of well under 10W.

One really important 3dprinting-specific to highlight: use a sock - in addition to other benefits, it has a dramatic affect on parasitic heat loss out the block, especially with cooling on.