A couple members of the Discord channel and I have found that switching a heatbed from the ‘Bang Bang’ heat-up method, which is the default in Marlin, to PID can reduce the effects of Z wobble due to the bed expanding and contracting when the controller turns the power on and off. When using Bang Bang, the heatbed will heat up at full power until it is a couple degrees above the target then shut off until it falls back to the target, as seen here. The bed will expand and contract with these small changes, which can also make it hard to manually level a bed that isn’t PID tuned.To test this, I printed three calibration cubes out of Inland PLA that has sat out for a year and a half. I printed at 205 degrees with a 0.2mm layer height on a Folgertech 2020 Prusa i3 with a Titan Aero hotend with no cooling fan. My bed uses a PCB heater. My build surface is glass with a PEI sheet on top of it. Here are my speed settings and firmware settings. Firmware is Marlin 1.1.8. Slicer is Slic3r Prusa Edition Version 1.37.2.PID Cube Front and back. Bang Bang cube front and back. Cube with heatbed turned off front and back.All three cubes side by side | PID top, Bang Bang middle, no heatbed bottomTl;dr: having your bed PID tuned can improve print quality and make it easier to manually level. It has to be enabled in marlin’s configuration under section ‘PID > Bed Temperature Control’ before it can be used. There is a warning in that section so before you use it, make sure it is safe. I don’t take responsibility if this burns your house down. http://ift.tt/2mP1Xlc
