Bed Thermal Runaway & cooling - A software problem
Hi,
I am having the Bed Thermal Runaway problem while printing a fairly small object in PETG.
Preheating works fine.
However after printing start the temperature drops from 90 deg.
At 80 deg I paused the print to avoid the error again.
Reselecting Preheat easily brings the temperature back up to 90 deg, but starting again it seems that the temperature cannot be kept.
This lead me to the conclusion that it is not a wiring problem it is somewhere in the software.
The fan was running at 128 (50%).
I found that if I reduced this to 25% then it was able to maintain temperature. Thus the Bed Thermal Runaway can also be a simple case of exessive cooling of smal objects where the fan cools the same area of the bed continously.
Food for thought...
Best Regards Stephen Odgaard
Copenhagen DK
Re: Bed Thermal Runaway & cooling - A software problem
What happens if you move your small piece away from the center of the bed where the bed thermistor is located?
---
Gert
Re: Bed Thermal Runaway & cooling - A software problem
Thus the Bed Thermal Runaway can also be a simple case of exessive cooling of smal objects where the fan cools the same area of the bed continously.
Food for thought...
100% correct.
I use to move small objects away from the middle of the bed where the sensor ist. Mostly this is enough to print with the desired fan speed and no thermal runaway.
Re: Bed Thermal Runaway & cooling - A software problem
I had a similar problem when printing an array of small objects in PETG, it seems there are some issues printing PETG with this machine due to the heaters on the bed and/or nozzle not being able to keep up with the power demand. The workaround is (1) set the bed to 75 C max. (2) Don't set the fan to 100% [but 25% is kinda low?] (3) If printing small parts, singly or in an array, keep them away from the center of the bed where the sensor is located. (4) ensure your ambient temperature is above 20 C.
So far I haven't had a recurrence.