How to choose the right silicone thermal pad?

Hardness, thickness, and insulation are all essential. CMAI INTERNATIONAL LIMITED reveals the misunderstandings in selection.

As electronic devices develop towards high performance and miniaturization, heat dissipation becomes a key factor restricting product reliability. As an important material for thermal management, the selection of silicone thermal pads directly affects the heat dissipation efficiency and equipment life. However, the product parameters on the market are complicated, and users often fall into misunderstandings due to ignoring key indicators. CMAIINTERNATIONAL LIMITED (hereinafter referred to as CMAI), as a global leading supplier of thermal interface materials, deeply analyzes the core elements of silicone thermal pad selection based on years of industry experience, helping users avoid common pitfalls. 

Misconception 1: Hardness selection is based on intuition only, ignoring the adaptability of application scenarios

The hardness of silicone thermal pads (usually expressed in Shore C hardness) needs to be dynamically adjusted according to the device structure and pressure conditions:

Low hardness (20-50 Shore C): Suitable for Mobile Phones, tablets and other devices with compact space and sensitive components. High compression rate can fill uneven surfaces and reduce contact thermal resistance.

Medium-high hardness (50-80 Shore C): Suitable for industrial equipment or scenarios that require support, such as servers or car electronics in a vibrating environment, to avoid material failure due to excessive compression.

CMAI recommends: The lower the hardness, the better. It is necessary to balance fit and structural strength. For example, a gasket that is too soft may harden due to silicone oil seepage after long-term pressure, which will increase thermal resistance.

Misconception 2: Thickness is "one size fits all", ignoring the relationship between thermal resistance and gap

The thickness selection needs to take into account the following factors:

1.Gap filling: The thickness of the gasket should be 1.2 times the actual gap (such as 1mm thickness for a 0.8mm gap) to ensure full contact.

2.Thermal resistance optimization: Thickness is proportional to thermal resistance. Ultra-thin gaskets (such as below 0.3mm) need to add glass fiber to enhance toughness, but may sacrifice some Thermal Conductivity.

3.Surface tolerance compensation: If the contact surface is uneven, a high compression gasket needs to be selected and the thickness should be appropriately increased.

CMAI case: Some customers directly selected a 0.5mm standard thickness silicone thermal conductive gasket without considering the PCB connection error, resulting in excessive local heat. After CMAI recommended the use of a 1mm high compression gasket, the temperature difference was reduced by 15%

Misconception 3: Ignoring insulation performance can lead to safety hazards

In high-voltage or high-frequency electronic devices, the insulation of silicone thermal pads is crucial. CMAI reminds that some companies choose non-insulating materials in pursuit of high thermal conductivity, which may cause short circuit risks. High-quality silicone thermal pads should have both high thermal conductivity (such as 1.5W/mK or more) and electrical insulation strength (≥5kV/mm) to ensure both safety and performance.

Conclusion

CMAI focuses on the research and development and production of silicone thermal pads. Its products are widely used in electronics, energy, automobiles and other fields, and are known for their high reliability and customized services. In response to different customer choices, CMAI has launched a full range of silicone thermal pad products, covering different hardness, thickness and insulation levels, and providing customers with professional choices.

For more information, please contact:https://www.cmaisz.com/