MT6M16534
© Fuji Electric Co., Ltd. All rights reserved.
5. Application of thermal grease
This chapter describes the thermal grease application for the product.
5-1
• It is recommended to apply thermal grease between the product’s aluminum base and the heat sink
to ensure heat dissipation to the heat sink. If the properties, amount, and application method of the
thermal grease is not appropriate, it may result in poor heat dissipation and lead to thermal failure.
Table 5-1 shows the recommended thermal grease properties and thickness
• Assuming that the thickness is uniform, the required amount (weight) of thermal grease can be
calculated from the following formula.
• We recommend using the stencil mask method to control the appropriate thermal grease thickness
(Fig. 5-1). The recommended stencil mask pattern is shown in appendix.
• It is recommended to check the spread of thermal grease by removing the product after mounting
and check the extent of spreading.
• In the case of liquid cooling, the temperature difference (temperature gradient) between the heat
sink temperature and the temperature inside the product becomes large. When mounting the
product to heat sink, secure a thermal grease coating amount that can absorb the distortion due to
the difference in thermal expansion when the temperature gradient is large.
• In the case of a multiple structure heat sink, the number of fastening parts increases and heat
transfer (diffusion) becomes uneven. Therefore, it is necessary to suppress the distortion, such as
securing the thermal grease coating amount in consideration of the generated distortion during
design.
Table 5-1. Recommended properties of thermal grease
Fig. 5-1 Thermal grease application
Squeegee
（
for applying
thermal grease
）
Thermal grease
(apply
to product’s
aluminum base)
Stencil mask
Stencil mask
fixing tool
Unit
Recommended value
Penetration (typ.)
-
328
Thermal conductivity
W/m
・
K
0.90
Thermal grease thickness
μm
100
±
30
Thermal grease
thickness (
μm)
Thermal grease
weight (g)x 10
4
Aluminum base area
of product (cm
2
)
=
Density of thermal
grease (g/cm
3
)
x
x
