Common Failure Causes in Kapton Heater and How to Prevent Them

https://thermal-devices.lucialpiazzale.com/temperature-control-for-a-pi-heater-sensors-setpoints-and-stability

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 kapton heater works best when these parts are planned together