Thermal transfer coefficient of hardened steel nozzles
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It depends on the the grease. Some high temp thermal grease is spec to 1000C.
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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
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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.
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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
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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.
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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
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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.
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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
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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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I've seen nozzles where brass or even copper is used for the bulk of the nozzle with just a thin layer or coating of hardened material. This should offer wear resistance but with a thinner layer of less conductive hardened material, there is better heat transfer. On the other hand brass nozzles are cheap and cheerful, maybe just change them weekly and carry on.
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…..............................On the other hand brass nozzles are cheap and cheerful, maybe just change them weekly and carry on.
Which is another major drawback of the Diamond IMO. I've got one with 0.9mm nozzle (for use with T glass) but it means making up a whole new assembly complete with heat sinks, thermistor, cartridge etc. I've got one built up but haven't got around to trying it yet 'cos it still involves a fairly major strip down and rebuild. A removable nozzle would make life soooo much easier.
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This is what's put me off mixing hotends so far is the fear of being unable to remove a blockage from a nozzle and having a large chunk of scrap brass in the waste metal bin shortly afterwards. Is there a way to have a cheap, easily replaceable mixing nozzle?
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This is what's put me off mixing hotends so far is the fear of being unable to remove a blockage from a nozzle and having a large chunk of scrap brass in the waste metal bin shortly afterwards. Is there a way to have a cheap, easily replaceable mixing nozzle?
No easily replaceable nozzle yet (or not one that I know of) - but I hold my hopes up. IMO the perfect mixing hot end has yet to be designed (but I'm working on it…...)
Having said that, the only time I've had issues with blockages has been caused by heat creep and a softening then hardening of the filament inside the heat sinks. Easily remedied by letting the hot end cool down properly before turning off the machine\fan (we live and learn). I am very careful with what goes into the hot end though, and I dare not try anything that might be abrasive in nature.
