Ender-6 over-temperature behavior
After getting my Ender 6 recently I was keen to try printing some things, and was impressed by what I could print within an hour. However, I noticed that, for longer prints (> 2 hours) the print would abruptly stop with no explanation. Moreover, if I cycled power the display would stay blank, and I would have to wait an hour before I could cycle power and see a normal startup display. And when I did see that display, I would be asked if I would like to resume my print.
This behavior seemed like normal programmed treatment of recovery from an over-temperature failure, even though the user interface never mentioned it. So as an experiment I removed the 8 screws retaining the bottom plate, and retried the long prints, repeatedly. In every case, the prints now proceeded to completion.
When I look at the layout of the Ender-6 underside, I arrive at the conclusion that the designers expected the power supply's exhaust fan to do most of the work of air movement. Unfortunately, the power supply is so efficient that its fan hardly needs to run at all, such that the Ender-6's underside temperature increases without bound. I verified this by placing a thermocouple in that underside interior and watched the temperature rise without bound during a print.
In the end, I cut a 32mm hole in the bottom plate, centered on the fan which cools the main board, and I fabricated a foam pillow to be interposed between the plate and the fan, such that the main board fan aspirates fresh air into the underside area around the main board. I'm pleased to report that all over-temp misbehavior now has ceased.
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