Cooling of the Mini Rambo board in our 6 Mini 1s has been a problem. I’m looking for a better solution that what I have done. I have wired the 80mm fan directly to 24V of the power supply. Now they run continuously and make too much noise.
Problem comes from stepper motors missing steps.
Z step skips have caused layer bulging. That is for sure.
X and Y not so sure about.
Extruder skips leave extrusion gaps that show in the outer skin perimeter. solved that by slowing the outer perimeter feed rate to 25mm/s (G1 F25 X…Y…E…). Slows production but make less trash.
As observed, the 80 mm fan never runs at full speed. The 80mm fan comes on when a print starts and goes off when a print finishes. That is good. But, the fan never runs at full speed.
I suspect the firmware sets the fan speed to control the processor’s temperature. Unfortunately the stepper drivers get hotter and mal-function.
When the 1st Z stepper driver failed and killed the mini Rambo , I replace the mini-Rambo and add
heat sinks. to the driver chips. Have since added heat sinks to all. That was not enough to stop the skipping.
A solution would be to change the fan logic in the firmware. That would have me maintaining parallel versions of firmware to the Lulzbot releases. Ughhh
Also though of insulating the processor by apply a layer of tape on the chip to insulate it. Have to study that further. Not certain about fan logic and location of temp sensor. That might just overheat the processor.
Thank you for reading, Mitch