Troubleshooting Slow Heat-Up in a PI Heater System

https://advanced-heating-guide.laurelcurrent.com/posts/why-kapton-heater-thickness-matters-in-compact-equipment

In sensors, a pi heater must deliver heat in a controlled way. It uses a thin resistive foil circuit laminated in polyimide film. One useful trait is fast response. Still, local hot spots can change the result