Why are Thermal Pads Supported?
Thermal Pads are supported because they are essentially made of putty. It’s important to distinguish there are about four big types of categories
-Thermal Gap Pads (usually thicker than .020’’ and softer)
-Silicone Pads (usually harder and below .020’’)
-Phase Change Materials (usually harder, but also thin)
What are some of the Supporting Materials for Thermal Pads?
The following materials I have seen support different types of thermal pads.
Aluminum is used for thermal interface pads as a support. The great thing. I’ve seen the aluminum used to do two things:
- It can offer a unique support for adhesive to be added onto as a medium for more critical applications where adhesive needs to stick.
- Aluminum can increase heat transfer through as thermal interface pads are supposed to do. However, with aluminum- you trade off the electrical isolation.
-Polyimide or Kapton
Kapton is great because it offers electrical isolation, but also is very difficult to cut through- offering great cut through resistance.
Fiberglass is great because it offers an ease of die cutting, but also offers great cut-thru resistance while also maintaining the electrical isolation. One thing I don’t love about fiberglass, the strings don’t slice away during die-cutting– they snap away, sometimes leaving strands.
I’m confused.. Haven’t you talked about Gap Pad 1500 that is Unsupported?
Ok, you caught me. Well, most thermal pads need to be supported, but I promise on this one. There is no thermal pad that exists below .020’’ in thickness that does not require a support of some sort. Take as an example, Gap Pad 3500ULM below .040’’ in thickness requires the fiberglass insert. This is because no thermal pad can self support without something as an insert to help handle it.