What is heat creep?

Heat creep is a popular term in 3D printing that refers to the heat of the hotend transitioning to the cold side of the hotend.

There should be a sharp temperature transition between the hot side of the hotend and the cold side, to avoid the filament swelling/softening which can cause a clog in the hotend or the extruder.

Most of the time, this problem occurs when printing PLA and TPU filament which has a lower glass transition temperature. This particular type of filament gets softer much easier than other types of materials.

It also applies to PETG filament if the enclosure temperature is too high, and gets close to the glass transition temperature of the filament.

To ensure a good printing experience, it is recommended to always keep the temperature inside an enclosure at least 10 degrees lower than the glass transition temperature of the filament.

Extruder clogs relate to heat creep

The most common reason for hotend or extruder clogs when printing with X1 Carbon or P1S is heat buildup inside the enclosure and heat creep inside the extruder.

PLA is the most common filament that gets clogged as it has the lowest glass transition temperature.

A notification to remind customers about specific requirements when printing filaments with a lower glass transition temperature has been added in the latest version of Bambu Studio.

How to avoid extruder clogs for X1 Series?

X1 Carbon comes with a Cool Plate specially designed to offer good adhesion for PLA at a heatbed temperature of ~35C. 
The reason why this plate is included with the X1 as default is to allow printing PLA with the front door and top cover closed on the printer.
When the Cool Plate is used, the chamber temperature inside the printer does not reach a value that is high enough to cause the softening of PLA filament.

Besides a lower temperature of the heatbed, the chamber fan is also set up to turn on when the heatbed temperature is set over a certain value when using PLA to facilitate keeping the temperature inside the chamber as low as possible and avoid heat creep causing clogs in the extruder or hotend.

To avoid extruder clogs for the X1 Series, please follow these guidelines:

  • When printing PLA filament, use the Cool Plate for best results. This will allow you to print with the front door and top cover closed without generating issues
  • If a different plate is used, like Textured PEI Plate or High-Temperature PEI Plate, it is recommended to print PLA with the front door open and/or the top cover removed to help keep the chamber temperature low, thus minimizing the chances of getting an extruder or hotend clog.

More information about different Bambu Lab plates is available here.

If you already have a clog and need help unclogging the hotend or the extruder, please follow our Wiki article explaining the process.

How to avoid extruder clogs for P1 Series?

P1S comes with a Textured PEI plate out of the box. The requirement to print PLA successfully on the P1S Textured PEI plate is to use a heatbed temperature of 55C. 
Having a higher temperature of the hotbed will contribute to the passive temperature increase inside the printer. This leads to clogs occurring inside the P1S extruder or inside the hotend, as the higher temperature leads to softening the filament before it gets melted and printed by the hotend.

The chamber fan is set up to turn on when the heatbed temperature is set over the 50C value when using PLA to facilitate keeping the temperature inside the chamber as low as possible and avoid heat creep causing clogs in the extruder or hotend. But if the printer is sitting in a warmer environment, the fan might not be able to keep the temperature inside the chamber low enough to avoid extruder clogs/

To avoid extruder clogs for the P1 Series, specifically the P1S please follow these guidelines:

  • When printing PLA with the default Textured PEI Plate or High-Temperature PEI Plate, it is recommended to print with the front door open and/or the top cover removed to help keep the chamber temperature low, thus minimizing the chances of getting an extruder or hotend clog.
  • Aftermarket plates which require a heatbed temperature higher than 50C to work reliably also need the front door and/or top cover removed to avoid extruder or hotend clogs.
  • If you wish to print with the front door and top cover installed, we recommend using the Cool Plate which requires a lower temperature of the heatbed (35C)

More information about different Bambu Lab plates is available here.

If you already have a clog and need help unclogging the hotend or the extruder, please follow our Wiki article explaining the process.

What about P1P?

The P1P is an open-frame design, meaning that it does not have an enclosure to trap heat inside it for higher-temperature filaments.

It is well suited for filaments like PLA, TPU, and PETG and it will not require any changes to avoid hotend or extruder clogs as the heat doesn’t reach the print head.

If you have decided to enclose the P1P with our P1S upgrade kit, or with a different enclosure, please follow the same recommendations we have for the P1S to print PLA with the front door and/or top cover removed. This will help avoid any extruder or hotend clogs.

Recommendation Table for Filament

MaterialsHeatbed TemperatureUpper Glass Cover Plate Removed?
PLA/PLA-CF/PLA-GF45~60℃Yes
ABS90~100℃No
PETG/PETG-CF60~80℃No
PET-CF80~100℃No
TPU35~45℃Yes
ASA90~100℃No
PVA45~60℃Yes
PC/PC-CF90~110℃No
PA/PA-CF/PAHT-CF90~110℃No

Other considerations

Besides avoiding heat creep, printing PLA with the front door and top cover removed will contribute to better print results. PLA and TPU filament can benefit from additional cooling during printing, leading to better overhangs and a cleaner overall look of the finished model.

When printing with a higher enclosure temperature, you might not get a clog but the print quality might still suffer from the lack of cooling, as the airflow provided by the part cooling fans is hotter, meaning that the cooling performance can be impacted.

Another consideration is when printing in a very low environment temperature. If you are printing PLA, TPU, or PETG and the environment temperature of the printer is very low (ex: 5C-10C) then you might be able to print with the front door closed and top cover installed and benefit from the increased temperature inside the chamber. 
This is an isolated scenario, and if you are following this guideline but get clogs inside the extruder or the hotend, it is still recommended to open the front door slightly to allow some of the hot air to escape, and cool air to enter the chamber.

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