Very thin heatsink tape (Phase Change Material) - Page 1
Forum section: electronics / repair

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 16, 2022, 12:36:14 pm
content: Hi,can anyone identify/source this green heatsink insulating/thermal tape? It measures about 0.1mm thick.Which doesn't look thick enough as an arc has punched a hole in it.This is the primary side of an SMPS/audio amplifier running on 240v.2nd photo added for better context.

author: brabus
author_rank: Frequent Contributor
timestamp: November 16, 2022, 12:43:10 pm
content: It looks like painted mylar, a very common material used to obtain an additional layer of reinforced insulation.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 16, 2022, 06:45:34 pm
content: Quote from: brabus on November 16, 2022, 12:43:10 pmThanks, I haven't seen this method before.The main heatsink has a transparent insulator with rectangular holes cut out to accommodate the Mosfet heatsinks, and this tape is then placed over this rectangular "hole". The Mosfets are thus separated from the heatsink by only the 0.1mm thick tape.It seems either the tape is too thin, or the rectangular cutout not big enough, so the tape may have been stretched or damaged by the Mosfet heatsink forcing the tape over the edge of the hole, resulting in an arc between Mosfet and heatsink.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 23, 2022, 08:09:46 pm
content: I believe the material is this:https://www.farnell.com/datasheets/1323719.pdfAnd I also believe it was placed ABOVE the insulated sheet during manufacture, instead of directly on the heatsink, where the insulated sheet with cutouts for the Mosfets should have been placed on top.This did indeed damage the material, causing an arc from heatsink to Mosfets which took out the mains PCB fuse.Fortunately this was all on the mains side, so the rest of the SMPS and the attached Class D amp survived.This is a Pioneer XPRS12.

author: Vicus
author_rank: Regular Contributor
timestamp: November 23, 2022, 08:40:56 pm
content: I did ask for information about some time ago:https://www.eevblog.com/forum/projects/thermal-interface-isolator-that-use-phase-change-material/I can't buy easily berquist product so I did use (yesterday) a very similar (thin film with phase change compound) product from fischer elektronik and I think they work great. The downside is that I think they can't reused or at least I don't know if can.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 23, 2022, 09:57:26 pm
content: Farnell and Mouser stock this product?

author: Vicus
author_rank: Regular Contributor
timestamp: November 24, 2022, 01:34:32 pm
content: https://www.mouser.it/c/?product=Phase%20Change%20Materialunfortunately I don't have enought experience to give advice. I hope that some one in this forum can tell us all the tips about.

author: 2N2222A
author_rank: Regular Contributor
timestamp: November 24, 2022, 09:35:16 pm
content: I believe Digikey does sell a 0.1mm electrically insulating thermally conductive pad. Maybe it's 0.25mm which I'm sure they they have that at least.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 24, 2022, 10:38:37 pm
content: This is Phase Change Material.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 25, 2022, 09:59:55 pm
content: Quote from: Vicus on November 23, 2022, 08:40:56 pmI'm not sure why possible reuse of this product is particularly important to you.It would only be needed to be replaced under a fault condition.

author: 2N2222A
author_rank: Regular Contributor
timestamp: November 25, 2022, 11:49:31 pm
content: If I understand correctly, phase change material is not electrically insulating. It is used in place of heat sink compound where there is too much gap for heat sink compound to be used.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 26, 2022, 01:40:37 am
content: Quote from: 2N2222A on November 25, 2022, 11:49:31 pmI think the product here comprises of a thermally conductive and insulating base, with layers of Phase Change Material each side.I believe the idea is that the Phase Change Material is able to absorb heat by enabling a change in structure, and then give it back on restructure once the hot condition has subsided.