During a print a lot of plastic ended up ripping the nozzle's yellow insulation strap.

Can printing without this insulation around the fusion chamber damage the printer?

If there is no chance of damaging the printer, how likely is it that the prints will be affected by the absence of this insulation

highlight of the insulation strap


3 Answers 3


Removing the insulation will not damage the printer, although it may affect the quality of the prints. The insulation is, after all, there for a purpose.

Allowing too much heat to escape radiatively from the heater block will reduce the maximum flow rate, since less energy will be available to heat the filament, and you may need to reduce your printing speeds or increase your nozzle temperature.

A bigger problem is that heat radiating from the heater block can cause already extruded filament to sag, especially when printing details and intricate infill. If the nozzle remains too long in any area, already extruded filament is likely to soften and deform. Without adequate insulation, the only way to counteract this is by increasing part cooling, and this will remove even more energy from the heater block.

Either fit new insulating tape or buy some silicone socks, since they are readily available for MK7/8/9 heater blocks. Then print a couple of Benchies, both with and without a sock, and compare the results.

  • $\begingroup$ There is not less energy available unless the block is excessively cooled by the part cooler. The thermistor will read the temperature, when it drops below a certain temperature the heater will heat up. It also does that with the insulation on. It is expected that the heater will be scheduled more without insulation. $\endgroup$
    – 0scar
    May 14, 2019 at 12:44
  • $\begingroup$ @0scar You're right. I was speaking too much from personal experience. I'll edit my answer. $\endgroup$
    – Mick
    May 14, 2019 at 13:08
  • $\begingroup$ Thank you, I'll look into silicon socks. According to what I read it's thermal conductivity is far higher than that of the former insulation material but it'll still be better than just air, and it'll avoir PLA buildup around the nozzle which is basically what destroyed the insulation band. $\endgroup$ May 14, 2019 at 14:38
  • $\begingroup$ The second paragraph is incorrect. That is only happening when the block is cooled too much, more than the heater can supply. I've been printing with (cotton and silicon) and without insulation for years, works just fine. $\endgroup$
    – 0scar
    May 14, 2019 at 21:23

No, without the insulation you can print without a problem. I've been printing for years with (cotton or silicone) and without insulation, works perfectly. Although heat radiates from the heater block, I've never experienced issues that it causes overheating of your printed parts.

Note that the insulation tries to contain the heat in the nozzle preventing heat to leak to the surroundings (less energy is used/wasted). As such you may need to do a new PID tuning (certainly when the print cooling fan is incorrectly positioned as such that it cools the hotend heater block), but printing should just work fine if the print cooling fan is in the correct position.

  • $\begingroup$ I consider both answers deserved to be tagged as "the one", but I can't flag both $\endgroup$ May 14, 2019 at 14:29
  • $\begingroup$ @MathieuVIALES No problem, it is good to have multiple answers! Mine does not address the damage side. $\endgroup$
    – 0scar
    May 14, 2019 at 21:33

Insulation of the nozzle is crucial. I removed it and put a silicon sock on a CR-10. I constantly got heat creeps even at 10C lower temp. Then I removed the sock and printed a 12 hour part with significant quality loss. It did finish the job. With silicon it stopped after 5-6 hours. I suppose that with the sock the upper part of the heat block which is uninsulated leaves more energy go up than without a silicon sock. Then I put cotton all around the heat block. I even put the cotton at the side of the thermistor. And kapton tape. The results are really really perfect. Always talking for the CR-10 stock nozzle and fans. If you don't have insulation you need better fans. All the heat goes up to the heatbreak and softens the fillament.


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