In servers, 5G telecom equipment, industrial power supplies, and automotive electronics, a chip package and a heat sink may appear flat. At a microscopic level, however, machining marks, component-height tolerances, and assembly warpage leave small voids between the two surfaces. When those voids contain air, they become high-resistance sections in the heat-flow path. Increasing screw torque is not always the right answer because excessive force can add unwanted stress to the PCB, package, solder joints, or connectors.
Thermal design therefore depends on more than the conductivity value printed on a datasheet. The interface material must also conform to real surfaces and fill the specified gap under an acceptable mechanical load. The Lixing Thermal Pad / Silicone Gap Pad is a soft, compressible sheet designed for placement between heat-generating components and cooling structures, helping form a more continuous contact path.
Why do microscopic air gaps increase contact thermal resistance?
Chip packages, metal heat sinks, and equipment housings all have microscopic peaks and valleys. When two solids are assembled, the real area of direct contact is smaller than their visible geometric area. The remaining locations contain air. Because air transfers heat much less effectively than typical solid thermal-interface materials, poor conformity can limit the total thermal path even when the heat sink itself is well designed.
Under suitable compression, a thermal gap pad deforms around local surface features, displaces part of the trapped air, and increases effective contact area. This makes low-pressure conformity an important design factor. For thin PCBs, precision connectors, and large modules, the objective is to establish repeatable thermal contact without applying unnecessary mechanical load.
How it works: conductivity and conformity must be evaluated together
1. Softness helps the pad follow assembly tolerances
The product page lists hardness options from 5 to 40 Shore B. This range allows engineers to select a grade according to clamping force and structural requirements. Softer grades can follow component-height differences under lower pressure, but a complete selection also considers pad thickness, compression, recovery, and long-term retention. Hardness should not be evaluated as an isolated number.
2. Conductivity grades from 1 to 10 W/m·K address different heat loads
The Lixing thermal gap pad series offers conductivity grades from 1 to 10 W/m·K. Higher-conductivity grades may suit components with concentrated heat flux, but engineers should still assess contact area, material thickness, compressed condition, heat-sink capacity, and ambient temperature as one complete thermal path.
3. The compressible layer also supports tolerance and vibration management
The elasticity of the silicone sheet supports surface conformity and provides a degree of cushioning where assemblies experience vibration or tolerance stack-up. In GPU boards, telecom modules, power supplies, and automotive power electronics, this can help reduce direct loading from a rigid heat sink onto sensitive components. Dimensions, geometry, color, and surface tack can be customized for the assembly process.
What should engineers confirm before selecting a gap pad?
Actual gap and tolerance: Measure the highest and lowest component positions and the assembled gap range instead of choosing thickness only from nominal dimensions.
Available clamping pressure: Confirm the load limits of the PCB, package, and connectors before selecting hardness and compression. Avoid excessive torque merely to improve contact.
Heat load and thermal path: Select the conductivity grade according to device power, contact area, and heat-sink performance rather than comparing W/m·K values in isolation.
Electrical and flammability requirements: The product page lists insulation options and UL 94 V-0/V-1 grades. Qualification data should be confirmed for the exact grade used in the final design.
Production assembly: For locating, pre-applying, or automating the pad installation, consider one-sided or two-sided tack, die-cut geometry, and roll-format supply.
Typical applications
CPU and GPU cooling: Filling height differences between processors, memory or power components, and the heat sink to improve large-area contact.
5G telecom and industrial power: Building a heat-transfer path between components and a metal enclosure where clamping pressure is limited.
Automotive and high-power electronic modules: Managing heat flow, structural tolerance, and vibration cushioning with customizable shape and tack.
The value of a thermal gap pad is not simply placing a high-conductivity sheet inside an enclosure. The selected softness, thickness, and compression must allow the material to contact both surfaces in the actual assembly. Engineers comparing power levels, gap ranges, or mechanical loads can review the Lixing Thermal Pad product page and confirm the appropriate grade against the complete thermal and mechanical design.
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