How to Maintain Mica Heating Plate for Stable Day-to-Day Heating
https://thermal-tech-hub.lucialpiazzale.com/common-polyimide-heater-mistakes-and-how-to-avoid-them
Many heating problems look like a power problem at first. In practice, the cause may be contact, heat loss, sensor position, or poor fit. A mica heating plate works best when these parts are planned together