3D Printer Heat Creep Issue and How to Fix It
Among many of 3D printing challenges, heat creep is also quite a frustrating problem that most 3D printer users can meet. In this article, we'll talk what 3D printer heat creep is, and how to fix heat creep problems.
What is 3D Printer Heat Creep?
3D printing heat creep means heat sneakily creeps from the hot end to the cold zone, which is also referred as heat sink section of the print head. It leads to earlier filament melting before the hot zone. And filament clog happens inside the heat break, or the thermal barrier tube.
And according to experienced users, 3D printer heat creep often occurs in the middle of a print especially when heating reaches the highest temp. And it's rare to see heat creep happening after a print.
Symptoms of Heat Creep
3D printer heat creep often ends up at unfinished half printed objects with hairy tops. And heat creep tends to happen more on all metal hot ends since heat travels much easier through metal components.
What Causes Heat Creep?
There are many factors can lead to heat creep, for example, too high hot end temperature, insufficient hot end cooling, too long heating time for filament, poor quality heatbreak, too much retraction length and too low printing speed, and hot end designs.
Too high hot end temperature can force excessive heat travelling to parts needs no heating, and heat creep happens.
Insufficient hot end cooling caused by slowly running or improper working cooling fan also leads to heat travelling to unnecessary parts and melt the filament before melt zone.
If filament stays too long time in the hot end, too long heating time happens. Hence heat travels up and melt filament before the melt zone.
Poor quality heat break with higher thermal conductivity can be another cause of heat transfer to the cold end and leads to heat creep.
When too much retraction length is set, melted filament in the hot end may pull up to heat sinks and finally leads to clog, and heat creep appears.
Too low printing speed results in inconsistency between the extruded filament and those inside the extrusion system.
Ho end design can also be a cause of heat creeps. Different hot ends have different capacities to deal with heat. Usually, an all-metal hot end is more inclined to travel heat easily inside the hot end assembly, and when it combines other factors, heat creep tends to happen and affect your print.
How to Prevent & Fix 3D Printer Heat Creep?
Now we'll follow above mentioned causes to learn how to fix 3D printing heat creep.
Solution 1 - Set lower hot end temperature
When heat creep happens, the first thing we do and the easiest way is to set a lower hot end temperature to reduce excessive heat traveling up and to prevent earlier melted filament.
But when doing this, be always aware of the required temperature range to heat and melt your specific filament. Too low hot end temperature leads to insufficient filament melting and clogged nozzle.
Solution 2 - Rise fan speed or replace improper fan
Rise fan speed or replace improper fan should be the next step we try to prevent heat creep from happening.
Rise fan speed by 10% per time to find the fittest setting for your specific printing until heat creep disappears. If the fan speed reaches 100% or warping happens during the process but heat creep still exists, then proceed to other solutions.
Solution 3 - Rise printing speed
Gradually rise printing speed can be another method to fix heat creep problem. It's better to rise the printing speed at 2-5mm/s per time to avoid huge decline of printing speed caused under extrusion and even clogged nozzle.
Solution 4 - Set lower retraction length
Too long retraction length pulls too long filament upwards and half melted filament goes back to the throat. At this circumstances, heat creep happens too. Gradually lower retraction length at 0.5mm per time to find out the appropriate retraction value for your print.
Solution 5 - Use heat breaks with lower thermal conductivity
Heat breaks with higher thermal conductivity travel heat faster and heat goes upward quickly from the hot zone.
Commonly, a stainless steel heat break is the stock type for most budget 3D printer hot ends. For lower thermal conductivity, use a titanium alloy heat break as a replacement. Another option is to use a bi-metal heat break with copper upper part for better heat dissipation to assist heat sink and titanium alloy lower part to prevent heat traveling.
Solution 6 - Use PTFE -lined hot end
Replacing all metal hot end with a PTFE-lined hot end can be helpful to solve heat creep problems at some circumstances.
A PTFE-lined hot end comes along with a removable PTFE tube, which insulates heat traveling before the filament is pushed into the melt zone.
Just remember, all metal hot end is only an assisting factor of heat creep. Thus, using a PTFE-lined hot end as replacement is the last resort that we do to solve heat creep 3D printing.
Other factors we should consider:
There are many other factors we should consider when dealing with 3D printer heat creeps.
1. Clean hot end assembly
Dirty hot end or filament residues inside or on its surface can lead to heat creeps or other problems. Remember to wipe and clean both the exterior and interior of the hot end components including the fan after several prints.
2. Check or replace PTFE tube
PTFE tube insulates heat and prevents unexpected earlier filament melting. Always check if the PTFE tube is correctly installed or in good condition. Cut burned end of the PFTE tube and reinstall it.
Also, you can replace the stock PTFE tube with a higher quality tube.
3. Use high quality filament
Use high quality filament also reduces the possibility of heat creep.
4. Power off your printer if you don't print
If you don't print anymore, just power off the printer. Continual heated hot end without break tends to accumulate heat and result in heat creep. Some experienced makers noticed it and found a break of the printer is helpful.
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