this post was submitted on 05 Dec 2023
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11
Issues with layer adhesion post bimetal heatbreak and hardened steel nozzle install. (self.3dprinting)
submitted 11 months ago* (last edited 11 months ago) by BigDanishGuy to c/[email protected]
6 comments fedilink hide all child comments
 

I apologize for the links below being vendor specific, but the linked products are the specific products I have used. I have no affiliation with the shop other than they offer to bill my job instead of having me pay upfront and then get the expenses redeemed. (I have tried making this both subscript and super script with respectively ^ and ~, but none works on lemmy)

I seek advice on proceeding with the setup and acquiring an acceptable printing quality.

Background

I have recently "upgraded" a creality cr6 se at work. I installed a spider steel/PEI plate (https://3deksperten.dk/products/spiderflexiplate-double-system-255x245-ex-cr-6-se), a bimetal heatbreak https://3deksperten.dk/products/3dsupreme-titanium-alloy-bi-metal-heatbreak-cr6-se) and a hardened steel nozzle (0.4mm from this kit https://3deksperten.dk/products/creality-3d-3d-printing-up-market-nozzle-kit-8-pcs)

Findings

Testing this new setup I used the PLA spool I had been printing with days before without issue. The new and old nozzles are all 0.4mm.

What I discovered was that I couldn't get any adhesion to the built plate, some spray glue (this exact make and model https://3deksperten.dk/products/printafix-100ml) fixed that. Then layer adhesion was an issue. So I upped the temp to the max for this PLA and increased the extrusion rate. First 10 layers or so were somewhat ok, but the rest delaminated instantly.

I then opened a brand new spool of PLA, thinking that the old spool had moisture issues. Cranked the temp to max, 210°C, added 5°C to the bed and applied a strong shot of spray glue. This time the print actually got done, but the parts where Cura's tree support was supposed to be supporting, the layers seem to come apart. The rest of the print was somewhat ok, though not great.

Current considerations

  • Maybe I attempted too much at the same time. I may try swapping the nozzle back and only deal with the plate and heatbreak.
  • The heat break may be install wrong. The nozzle was screwed in all the way, loosened a few turns, then the heat break was screwed in all the way. The nozzled was then tightened. No heating was done. I may try giving the heat break a few turns before installing the old nozzle again.
  • Should I have heated hotend before tightening the nozzle?
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[–] [email protected] 6 points 11 months ago (1 children)

Layer adhesion almost always means plastic is extruding too cold. Especially if the adhesion problems are happening on layers off the build plate. Keep bumping the temp and maybe use less part cooling fan- you can't really make it worse at this point.

Hardened steel nozzles do not conduct heat nearly as well as typical brass nozzles. (The thermal conductivity of steel is around 40w/m-K for high alloys, while for brass it is 110w/m-K). It cannot heat the plastic up nearly as fast.

I usually start at 210C for PLA on my Prusa mk3's with a brass nozzle, and will back down to 200/205 if there's more overhangs or too much stringing. But on the printer set up with a steel nozzle I ended up around 225C to get results comparable to 210 on the brass nozzle.

[–] rug_burn 2 points 11 months ago

This. I'd avoid using the hardened nozzle until you have a filament that requires it (glow in the dark, wood, CF, etc). Between the part cooling fan and the poor thermal conductivity of the steel (assuming you do have the nozzle fully tightened), it's an uphill battle. If you really need that nozzle more or less permanent, try using an enclosure to keep ambient temps up, but note PLA doesn't necessarily do well in enclosures that get too hot

[–] [email protected] 5 points 11 months ago

210 as max temperature on PLA? I print PLA at 215 on my printer, although I have no clue how accurate the nozzle temperature sensor actually is on my machine. I think you're just printing it too cold.

Another thing to consider is that the steel nozzle is going to be less thermally conductive than a brass one, so depending on where the nozzle temp sensor is you may not even be achieving your temperature setpoint by the time the material makes it to the end of the nozzle, and you may have to bump it up a bit to compensate. You can check with an IR thermometer if you have one lying around. With the old nozzle it may have been conductive enough that your extrusion temperature was okay, but with the new one now it isn't.

TL;DR: Try upping your nozzle temperature a bit.

[–] [email protected] 1 points 11 months ago

Always heat up nozzle before tightening/untightening. And yeah up your temp or even better stick with brass nozzle for pla

[–] [email protected] 1 points 11 months ago

Have you tried PID tuning with the new nozzle and heatbreak? Maybe your printer isn't running at the temperature that it thinks it is.

[–] [email protected] -1 points 11 months ago

New Lemmy Post: Issues with layer adhesion post bimetal heatbreak and hardened steel nozzle install. (https://lemmy.world/post/9179879)
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