What are ways to avoid heat creep?
Things to consider (This is expanded from How is heat creep characterized?):

The air volume of the cooling fan on the hotend heat sink affects the temperature gradient across the heat sink.  Usually the size/geometry of the fan depends on the printer design, so the main parameter of a fan that controls air volume is the rpm.  I've noticed fans fitting hotends from 6,000 to 10,000 rpm.  The higher rpm the better as far as preventing heat creep.  Of course, make sure the fan is spinning properly.

The raising the temperature of the extruder increases the chance of heat creep.



A high resistive connection to the sensor will cause a lower that actual temperature reading.  Thus, the controller will raise the hotend to a higher temperature than set, which can cause het creep.


Razing the temperature of the heated bed, especially when the printer is in an enclosure, increases the chance of heat creep because this raises the temperature of the air the fan blows across the heatsink.


What can be useful is using higher extrusion and bed temperatures for the first layer, then set lower temperatures on subsequent layers  to reduce the chances of heat creep.


The slower the print speed the higher the chance of heat creep.  That's because a slower print speed gives the filament more time to heat up in the extruder.  Many slicers have a setting that slows down the print speed if a layer will finish below a given time.  If this slowed down time causes heat creep, the extrusion will stop when the printer reaches these smaller area layers.


Too much travel of the extruder without extruding has a similar effect because the filament isn't moving.  I verified that connecting isolated structures on a design with heat creep can eliminate it.  Using a little more material for thin walls is better than scraping prints.

Example: This is easy to demonstrate with PETG.  Design a table printed top down 100 mm square with four legs 5 mm square and 100 mm long.  Set the parameters so that you start to get heat creep when printing the legs.  Now put four 1 mm thick walls between the legs to get the heat creep to go away.

Sometimes if you start a second print without letting the extruder cool down from the first print, heat creep will cause the extruder to jam.


The heater block might be too close to the heatsink so that they bypass the heat breaks reduction in conducting heat.

Hotends for temperatures 245 °C and below can use such things as Teflon tubing in the heat break to isolate the filament from the metal.  But, +250 °C nozzle temperatures need all metal hotends.

The PID settings in the firmware might be letting the hotend temperature overshoot too high.