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Help: Rough prints after heat break and nozzle upgrade

aztz66_ddd

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Aug 28, 2025
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I'm new to this forum and hoping someone here can help me. I recently installed a new Bimetallic heat break and hardened steel nozzle on my Prusa i3 MK3S+ to print some more abrasive filaments, but now I'm getting a really weird and rough texture on my regular PLA prints. I've tried tweaking the retraction settings and temperature, but nothing seems to get me back to that smooth finish I used to have. Has anyone else run into this after a similar upgrade? Any advice would be appreciated!
 
I'm new to this forum and hoping someone here can help me. I recently installed a new Bimetallic heat break and hardened steel nozzle on my Prusa i3 MK3S+ to print some more abrasive filaments, but now I'm getting a really weird and rough texture on my regular PLA prints. I've tried tweaking the retraction settings and temperature, but nothing seems to get me back to that smooth finish I used to have. Has anyone else run into this after a similar upgrade? Any advice would be appreciated!
for an issue like this, usually the problem is almost certainly the hardened steel nozzle.
yeah, it's a fantastic upgrade for abrasive filaments, but it's a terrible thermal conductor compared to the stock brass nozzle.
That means it doesn't transfer heat to the PLA as efficiently, which leads to inconsistent melting and that rough texture you're seeing. Try bumping your print temperature up by 40-50 degrees F to compensate. That usually would fix the issue
 
I'm new to this forum and hoping someone here can help me. I recently installed a new Bimetallic heat break and hardened steel nozzle on my Prusa i3 MK3S+ to print some more abrasive filaments, but now I'm getting a really weird and rough texture on my regular PLA prints. I've tried tweaking the retraction settings and temperature, but nothing seems to get me back to that smooth finish I used to have. Has anyone else run into this after a similar upgrade? Any advice would be appreciated!
I agree with @NibblerNerd that it's a common trade-off with those upgrades but there's a confusion about the suggested temperature fix. It's true that hardened steel is a terrible thermal conductor, so a huge temperature bump like 40-50F often makes the rough texture worse on the MK3S+ due to heat creep. When the heater works that hard to hit the high temperature, it pushes too much heat upward into your new bimetallic heat break, causing the PLA to prematurely soften or clog slightly higher. That sticky PLA flowing through gives you the rough, inconsistent look. Instead, I suggest lowering your temperature first by 5-10C to reduce the overall heat load on the system. If you must increase it, only go up in tiny 2C steps, and most importantly, make sure your hotend cooling fan is running 100% and perfectly seated to fight that heat creep!
 
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