Thermal transfer coefficient of hardened steel nozzles



  • I recently swapped out one of my nozzles for an E3D hardened steel 0.4mm nozzle, a real one. I'm use to printing around 80-90mm/s with 2500 acl or so, I can go much faster I just prefer quality a bit more over speed. In any event with the hardened nozzle I'm having some trouble lately printing ABS. Depending on the print of course I eventually get to a point where the filament just appears to have cooled off even though the PT100 on that block is still showing a nice flat 240C.

    I've pulled the nozzle a few times, cleaned it all up in. Re-seated , tightened while hot, etc.etc. I've tried going a little hotter at 245C with no real change in the end result. The filament just starts looking like fiberglass and eventually bird nests.

    PETG doesn't really do all that much better, PLA seams fine. I've not tried PC with the nozzle. I've got 7 or so rolls of exotics sitting here unopened, all require the hardened nozzle.

    So I assume the nozzle is just not absorbing as much heat as it should be. Has anyone else had this issue with ED3's hardened nozzles ? I assume I'm just going to have to slow down the prints if I want to use that nozzle, just looking for confirmation. Brass prints wonderfully, zero issues even at double the speed, well other then some expected velocity related artifacts.

    Thanks,

    Jeff


  • administrators

    Jeff I have not printed with their hardned nozzes yet but what you are saying makes sense. Maybe there is some more infor on the e3d-online forum?



  • @T3P3Tony:

    Jeff I have not printed with their hardned nozzes yet but what you are saying makes sense. Maybe there is some more infor on the e3d-online forum?

    I'll check their forum, I actually did a bit of Google searching before posting here. I couldn't find anything conclusive. All I found was that the hardened nozzles shouldn't cause an issue and that others used them as daily drivers, nobody seamed to factor in print speeds, layer heights, etc. I know 80mm/s isn't all that fast but at 0.2 mm layer heights it's still sucking a bit of heat out of the nozzle.

    Thanks,

    Jeff



  • I know that the steel nozzles have much less capability to transfer heat than brass. I'm waiting on a tungsten nozzle from a kickstarter before trying some cf filaments. It should be optimum, excellent thermal transfer and very hard. https://dddmaterial.com/home/blog/tungsten-premium-nozzles-launched-kickstarter/

    I don't think of 80mm/s as fast but I'd be willing to bet average printing speed across the piece is probably 50mm/s. I've a volcano hotend and with a 30w heater cartridge I can't melt filament fast enough with a 1.0mm nozzle to get up beyond 50mm/s.


  • administrators

    Jeff an obvious question - have you tried turning the heat up significantly? Simplistically I presume it is the temperature of the filament leaving the nozzle that matters so as long as the hotter filament inside the top of the nozzle is not so hot it degrades it should still work. I agree 80mm/s max it not so fast as to present a problem.



  • @DjDemonD:

    I don't think of 80mm/s as fast but I'd be willing to bet average printing speed across the piece is probably 50mm/s. I've a volcano hotend and with a 30w heater cartridge I can't melt filament fast enough with a 1.0mm nozzle to get up beyond 50mm/s.

    Yah, that's why I'm a bit confused. I'm running an E3D 30w heater with just the normal updated E3D V6 block with a PT100 thermistor cartridge. I can do 160 mm/s with 4000 acl with the same heat block and heater If I use brass no problems. All indications are the hardened nozzle can't even do 80 mm/s 2500 acl 0.4mm width and 0.2 mm heights. The temperature is nice and flat, no fans running..etc. If I have to slow down I'm going to be a bit bummed out.

    Thanks,

    Jeff



  • It does sound as though it's not a lack of heat but a lack of thermal transfer to the filament. Next time your nozzle is out how about some copper grease between it and the heater block, I've never found it to be a hindrance (and the nozzle comes out easier later on).



  • I've recently upgraded my nozzle to a hardened steel one from e3d and noticed that my prints need at least 10-15c more heat to print well. Take this with a major pinch of salt though, because I also fiddled around with my thermistor cartridge at the same time and I have a feeling I overtightened the grubb screw and bent it. I'm replacing it soon though so we'll soon see which is at fault!



  • @GeckoBox3D:

    I've recently upgraded my nozzle to a hardened steel one from e3d and noticed that my prints need at least 10-15c more heat to print well. Take this with a major pinch of salt though, because I also fiddled around with my thermistor cartridge at the same time and I have a feeling I overtightened the grubb screw and bent it. I'm replacing it soon though so we'll soon see which is at fault!

    Unless it went into a fault state chances are you didn't throw it out of calibration so to speak. In my case I was really careful not to crush the cartridge and both my hot ends read the same at room temp. 10-15c, ouch that is a bit much.

    Thanks,

    Jeff



  • If they have a harden nozzle for an E3D volcano hot end block, you should go that route. Adding a thermal grease around the threads help reduce any thermal resistance.

    However, brass nozzles are around 110 W/(mK) thermal conductivity and stainless steel is around 16 W/(mK), so its a huge difference. Another option is to use a Tungsten nozzle since it has around 173 W/(mK) thermal conductivity. Not cheap, but not a lot of options if you need it hardened.

    https://dddmaterial.com/home/shop/product/tungsten-premium-nozzle-1-75mm-m6-0-4mm/



  • How's the thermal compound hold up to 315C ?, I like my PC.

    Jeff



  • It depends on the the grease. Some high temp thermal grease is spec to 1000C.



  • Ok, I have some various thermal compounds around. I'm going to hit them with 500C hot air from the rework station and see what survives 🙂 If none of them do I'll do some shopping. I think that could really help. I know it sure does on the heatsink side.

    Jeff



  • In your situation, the grease may help only a little. Your problem is the low thermal conductivity of the stainless steel nozzle. I suggest you print slower to allow time for the heat to get into the nozzle if you have issues. Upgrading to Volcano block increases the surface area contact based on the orientation of the heater and the length of the nozzle. That may solve your problem, but you would need the Volcano block and a new nozzle. The tungsten nozzle is a quick solution, but the cost is high and they may not have the part in stock yet.



  • Fine, I'll bow to the laws of thermal dynamics and slow it down…if I print a raft it becomes obvious really fast as it starts to look like fiberglass mesh. Guess I'll just play with the speeds.

    Jeff



  • Are you using a part cooling fan by any chance? If so, try turning it off or down at least for the first few layers just to see if it helps.



  • @deckingman:

    Are you using a part cooling fan by any chance? If so, try turning it off or down at least for the first few layers just to see if it helps.

    I've tried with it off, with it on only where needed, etc. Doesn't seam to matter much. It's as if the nozzle looses the battle of thermal transfer after so much filament has passed by. It does ok for small parts or layers without much filament, as soon as it hits a somewhat dense fill or worse a solid layer the game is over. The temperature from the PT100 in the meantime stays pretty rock solid. I'm still a die-hard ABS fan, I would warm up to PETG more if it wasn't so shinny. I like PC, but it's really a PITA.

    Jeff



  • Do you have a specific reason to go with stainless steel nozzle? Unless you're using abrasive material and fillers, brass is a better choice. I recall the original use was for food industries or where it can contact with humans. Brass has small amount of lead and is not suitable in those industries. Stainless steel is one of the WORST material to use for a nozzle from a thermal perspective. That is why they are used on the heat breaks. It was mainly to prevent or reduce the heat from the heater block moving to the throat/extruder area and cause clogs.



  • @ShadowX:

    Do you have a specific reason to go with SS nozzle? Unless you're using abrasive material and fillers, brass is a better choice. I recall the original use was for food surface or contact with human. Brass has small amount of lead and is not suitable in those industries. It is one of the WORST material to use for a nozzle from a thermal perspective.

    I have brand new rolls of Bras fill, Bronze fill, Aluminum fill, Copper fill, Carbon Fiber, Glow in the dark, wood fill, and I believe a couple others. My boss at work sent me a bunch of rolls over the holidays via Amazon. So my goal with the hardened steel novelize was to make it the daily driver as well as needed item for those filaments.

    Jeff


  • administrators

    I've been using the same 0.5mm stainless steel nozzles on my Ormerod ever since I built it 3 years ago and later upgraded it to dual nozzle. They have always worked well for me, although I only print PLA on that machine. I can see that brass might because better choice for something like a Volcano where more heat needs to be transferred.


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