Common Failure Causes in Polyimide Heater and How to Prevent Them
https://advanced-heating.bearsfanteamshop.com/materials-and-mounting-choices-for-a-mica-heater
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 polyimide heater works best when these parts are planned together