How to Fix Heat Creep (Filament) Problems for 3D Printing
4 min reading time
3D printing can be a fun hobby, but there are also many challenges you can encounter when 3D printing, especially when it comes to the heating element, which consists of six parts:
1. Nozzle: The bottom of the assembly where the filament will protrude.
2. Heat Block: The part above the nozzle that is heated.
3. Heat sink: allows air to flow through.
4. Neck: The part that is usually threaded and connects the heat sink to the heater block.
5. PTFE tube: This is a Teflon tube that connects to the hot end of the printer.
6. Coupler: All parts that are connected to the parts in items 1 - 5.
Filament should only melt in areas around the heater block and nozzle, which is called the melt zone. If it melts in other areas, that's when you'll start having problems printing.
One potential problem in 3D printing is thermal pinching, which involves heating the filament. Thermal pinching causes the filament to melt too quickly before it reaches the melting zone.
This problem can occur during printing or after printing (during cooling), but it is most likely to occur and be noticed during printing when the temperature is highest. You can see evidence of heat creep when your 3D printed part appears half-complete. You can also check for heat creep by pulling the filament and noticing that air bubbles have formed.
All of this can eventually lead to printhead clogging, but keep in mind that heat creep is not the same as other types of clogging, such as nozzle grinding.
There are many causes of heat creep, but the most common are related to tip temperature cooling and filament cooling time.
Excessive heat at tip temperature: If the tip is too hot, it can cause heat to escape to other parts. This is because the hotter the heatsink, the more heat it produces, and it can cause too much heat to escape to other unwanted areas.
Hot end fan not cooling enough: If your hot end fan is not on or running fast enough, there is insufficient cooling. This can lead to overheating in other areas and can also cause the plastic filament to melt before the material reaches the melt zone if there is no cooling to dissipate the heat.
The plastic filament is in the heating zone too long: The time at the end of the heating phase allows the heat to melt the plastic filament before it enters the melt zone.
Filament is in the hot end too long: The extra time spent assembling the hot end allows the heat to melt the filament before it reaches the melt zone, causing heat creep.
Thermal Tip Design: Not all thermal tips are equally heat-efficient, especially when combined with other factors such as all-metal thermal tips, which can easily conduct heat within the assembly, leading to excessive heat generation.
1. Reduce the temperature of the extremities: Excessive heat is generated in the heat sink area and this excess heat can be a carrier of heat to other areas. By reducing the temperature in this area, it can help prevent heat from traveling to other areas.
2. Increase fan speed: Increasing the fan speed will help prevent premature filament melting. You should initially set the fan to 100% and gradually reduce it in 10% increments. Choosing the right fan speed will help you minimize printing issues.
3. Increase print speed: Printing faster will take less time to reach the melt zone, which will reduce the chance of the filament melting prematurely. Consider adjusting the print speed in increments of 2-5 mm/s until you find the right value.
4. Change the heating set at the tip: If methods 1-3 do not work, try changing the tip heating assembly, choosing a PTFE-lined tip heating assembly with a removable PTFE tube, which provides more insulation and better maintains the melt temperature.
Source: https://all3dp.com/2/3d-printer-heat-creep/
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