Electronic thermal interface materials shall be selected based on interface gap, assembly pressure, rework requirements, thermal conductivity, dispensing process and component stress.
Elaplus TCMP thermal gel is recommended for irregular gaps and automated dispensing. TCMP 3375 can be evaluated for applications with high heat flux and curing positioning demands. GP 50 thermal putty suits large gaps and reworkable structures. GP 600 thermal pads are ideal for fixed-thickness mass assembly. If both thermal conduction and bonding are required, SIPA 1921 or SIPC 1928 are available options.
Why Thermal Interface Materials Are Needed Even With Heatsinks
Surfaces of chips, power modules and heatsinks look flat visually, yet they feature numerous micro bumps and air voids at the microscopic level.
Air has poor thermal conductivity. Direct contact between chips and housings leads to insufficient effective contact area and high interfacial thermal resistance.
Thermal gels, thermal pads and thermal putty fill these voids to form continuous thermal conduction paths.
Suitable Applications for Thermal Gel
TCMP Two-Part Thermal Gel Series
TCMP series adopts a 1:1 mixing ratio and offers multiple thermal conductivity grades to match different thermal design targets.
Key Features
- Compatible with automated dispensing
- Capable of filling irregular gaps
- Imposes low mechanical stress on chips
- Tolerant to certain assembly tolerances
- Resists free flow after curing, unlike ordinary thermal grease
Recommended Applications:
1、IGBT and power modules;
2、ECU, MCU and automotive controllers;
3、Communication base stations;
4、Optical modules;
5、AI server boards;
6、LED driver power supplies.
TCMP 3375: Curable High-Thermal-Conductivity Gel
As specified in the datasheet, TCMP 3375 is a one-part curable thermal gel with thermal conductivity of approx. 7.5 W/m·K, viscosity ranging from 280,000 ~ 350,000 cps and cured hardness of Shore 00 50.
Recommended Applications：
1、High heat-flux chips;
2、Interfaces requiring shape retention after dispensing;
3、Structures where material migration or pump-out shall be avoided;
4、Long-term thermal conduction between chips and heat dissipation housings.
Suitable Applications for Thermal Putty
GP 50: Pre-Cured Thermal Putty
GP 50 is a one-part pre-cured thermal putty with thermal conductivity of approx. 5.1 W/m·K according to the datasheet.
Recommended Applications：
1、Modules with large gaps or obvious tolerance variation;
2、Assembly lines without two-part dispensing equipment;
3、Structures requiring disassembly and rework;
4、Thermal interfaces of components sensitive to mechanical pressure.
Compared with liquid thermal adhesives, pre-cured thermal putty enables simpler application and requires no on-site mixing for curing.
Suitable Applications for Thermal Pads
GP 600: Preformed Thermal Pad
GP 600 can be customized to various thicknesses for products with stable gaps and standardized assembly.
Typical Applications：
1、Between PCBs and metal housings;
2、Between power modules and heatsinks;
3、Between memory chips and enclosures;
4、Communication equipment and server boards;
5、Mass-produced electronic products.
When selecting thermal pads, thermal conductivity is not the only factor. Compression ratio, hardness, thickness tolerance and actual assembly pressure also matter greatly.
Suitable Applications for Thermal Bonding Adhesives
SIPA 1921: Heat-Curable Thermally Conductive Silicone Adhesive
SIPA 1921 is a one-part heat-curable thermally conductive silicone adhesive, designed for structures requiring fast heat curing with simultaneous thermal conduction and flexible fixation.
SIPC 1928: Room-Temperature-Curable Thermal Silicone Adhesive
SIPC 1928 is a one-part room-temperature-curable thermally conductive silicone adhesive, suitable for assembly processes without high-temperature curing equipment.
Recommended Applications：
1、Bonding between heatsinks and PCBs;
2、LED module fixation;
3、Adhesion of power devices to metal baseplates;
4、Thermal fixation of power modules;
5、Positions requiring both sealing and heat dissipation.
Elaplus Thermal Material Comparison Table
| Product | Material Form | Suitable Scenarios | Main Advantages |
|---|---|---|---|
| TCMP Series | Two-part thermal gel | Irregular gaps, automated dispensing | Low stress, tolerance-adaptive |
| TCMP 3375 | One-part curable gel | High heat-flux chips | 7.5 W/m·K, shape retention after curing |
| GP 50 | Pre-cured thermal putty | Large gaps, reworkable structures | No mixing required, flexible assembly |
| GP 600 | Thermal pad | Fixed gaps, mass assembly | Controllable thickness, clean application |
| SIPA 1921 | Heat-curable thermal adhesive | Integrated thermal conduction & bonding | Flexible adhesion, heat curable |
| SIPC 1928 | Room-temp-curable thermal adhesive | Structures inaccessible to heating | Room-temperature application, sealing capability |
Does Higher Thermal Conductivity Guarantee Better Heat Dissipation?
Not necessarily.
Actual thermal resistance is affected by multiple factors:
- Thickness of thermal interface material
- Contact area between chip and material
- Air bubbles trapped at the interface
- Adequate compression of the material
- Surface flatness of components
- Long-term pump-out or cracking of materials
- Thermal design of the heatsink itself
A 5 W/m·K material that fully fills the interface can outperform a 10 W/m·K material with poor compression and trapped air gaps.
Conclusion on Thermal Material Selection
Choose TCMP series for irregular gaps and automated dispensing.
Evaluate TCMP 3375 if high thermal conductivity and curing positioning are needed.
Select GP 50 for large gaps and reworkable assemblies.
GP 600 fits standardized mass production with fixed thickness requirements.
For integrated bonding and heat dissipation, opt for SIPA 1921 or SIPC 1928.
FAQ on Thermal Interface Material Selection
What is the difference between thermal gel and thermal grease?
Thermal gel can be cured or maintain stable form, with risks of long-term migration and pump-out better controlled.
Can thermal pads be reused?
Judgment depends on compression deformation and surface damage. Repeated reuse of the same pad is generally not recommended for products with strict reliability requirements.
What gap size is suitable for thermal putty?
Parameters shall follow the official TDS and structural pressure; selection cannot rely solely on material type.
Can thermal materials crush chips?
Excessively high hardness or over-compression may impose heavy stress on chips and PCBs. Material hardness and compression design must be verified.
