Thermal Pads

Thermal Gap Pads, Thermal Tapes, Sil-Pads, Phase Change Thermal Pads, Thermally Conductive Tapes

Thermal Management is becoming an increasingly important part of application design. Luckily Henkels’ Bergquist offers TIMs(Thermal Interface Materials) to allow for management of thermal issues. NEDC die-cuts thermal interface materials into finished parts that are called thermal pads. These thermal pads come in many forms as there are many applications. There are really two groups of pads with an incredible amount of overlap in between. There are Gap Filling Pads that provide thermal conductivity in the absence of a lot of pressure- these pads tend to be thicker .015” -.250”. On the other hand, there are thin thermal pads that usually utilize pressure such as clips or screws to provide sustainable pressure to allow for lowering thermal impedance. These thermal pads usually range from .030” to .005”.

Gap Filling Pads

Thermal Gap Pads

Gap Pad® is a gap filler used between electronics and heat sinks as a thermal interface. The benefit of Gap Pad is that it may conform to the different surfaces and textures that may be present in electronic applications. Gap Pad may be used to fill air gaps, inconsistent surface topography, and other odd surfaces. The benefits it provides are:

• Low-stress vibration dampening

These gap filling pads can dampening vibrations due to the softness and durability of the pads.

• Elimination of air gaps to reduce thermal resistance

Elimination of air-gaps is a function of conformability, pressure, and softness. Gap Pad® is adept at providing a solution that can help to eliminate air-gaps, reducing heat in the end application.

• High conformability to reduce interfacial resistance

Different topologies along the application can create interfacial resistance causing air-gaps. Having good conformability and low modulus can allow the Gap Filling Pad conform to the surface easier.

There are a significant amount of Gap Pad® offerings for different applications. This allows for a good mix of performance, price point, and assembly use.

• Gap Pad® VO Ultra Soft (VOUS), GPVOUS aka GAP PAD TGP 1000VOUS
• Gap Pad® VO Soft (VOS), GPVOS aka GAP PAD TGP 800VOS
• Gap Pad® 1500S30, GP1500S30 aka GAP PAD TGP 1300
• Gap Pad® 1500, GP1500 aka GAP PAD TGP 1500
• Gap Pad® 2000S40, GP2000S40 aka GAP PAD TGP 2000
• Gap Pad® 5000S35, GP5000S35 aka GAP PAD TGP 5000
• Gap Pad® 2200SF, GP2200SF aka GAP PAD TGP 2200SF
• Gap Pad® 7000ULM, GP7000ULM aka GAP PAD TGP 7000ULM
• Gap Pad® 3500ULM, GP3500ULM aka GAP PAD TGP 3500ULM

Usually Gap Pad® is not available with PSA. However, Gap Pad® VOUS, VOS, VO are all available with PSA(Pressure-Sensitive Adhesive). Although, inherent tack is available on most Gap Pad® products to aid in assembly. It is important to note that adhesives may further impede the thermal pathway of the material. NEDC die-cuts Gap Pad® with conventional die-cutting machines through steel-rule dies.

Sil Pad®

Sil Pad® is a thermally conductive insulator that has a wide reaching use in different applications. Sil Pad® is usually provided on the thinner side. These pads require higher pressure than their gap filling pads mentioned above. The benefits of Sil Pad® include:

• Great thermal performance

These thermal pads are designed for great thermal performance. It is important to keep in mind that while thermal conductivity is an important metric, its not the only metric. Thermal impedence, thickness, hardness are all important qualities to look at.

• Eliminates clean-up from thermal greases

Clean-up from greases can create an extraordinary mess. Having a neat, clean solution for your thermal issue can be incredibly useful.

• Sil Pad® has an efficient cost structure

Sil Pad® is able to offer great performance, ease of assembly, good reliability and a great cost/benefit ratio.

Sil Pad® has a long list of different products, all of these different types of Sil Pad® have different qualities and benefits.

• Sil Pad® 400, SP400 aka SIL PAD TSP 900
• Sil Pad® 800, SP800 aka SIL PAD TSP 1600
• Sil Pad® 980, SP980 aka SIL PAD TSP 1680
• Sil Pad® A1500, SPA1500 aka SIL PAD TSP A2000
• Sil Pad® 1200, SP1200 aka SIL PAD TSP 1800
• Sil Pad® 2000, SP2000 aka SIL PAD TSP 3500
• Sil Pad® A2000, SPA2000 aka SIL PAD TSP A3000

NEDC die-cuts or otherwise converts Sil Pad® products into finished thermal pads through waterjet cutting or die-cutting. Sil Pad® is usually available with pressure-sensitive adhesive depending on the specific pad. In addition, some are available with tape on both sides of the pad.

Phase-Change Thermal Pads

Phase-Change materials are heated into place during the assembly. These thermally conductive materials provide similar benefits to thermally conductive pads such as Sil Pad. Hi-Flow is a phase change material provided by Henkels’ Bergquist. Hi-Flow is useful in applications requiring a replacement for grease as a thermal interface between CPU or power devices and a heat sink. The benefits of Hi-Flow material include:

• A replacement to grease, with the benefit of saving time and money

As discussed with other thermal pads, replacing grease is a principle interest. This is because thermal grease can be difficult to apply properly, and difficult to clean up.

• Easy handling, not tacky at room temperature

Tackiness at room temperature can be difficult to handle. Having a neat, clean solution that is easy to apply to the application before the material activates can be very convenient.

A few Hi-Flow products include:

• Hi-Flow® 105, HF105 aka HI FLOW THF 900
• Hi-Flow® 225F-AC, HF225F-AC aka HI FLOW THF 1000F-AC
• Hi Flow® 225U, HF225U aka HI FLOW THF 1000U
• Hi-Flow® 650P, HF650P aka HI FLOW THF 1500P
• Hi-Flow® 625, HF625 aka HI FLOW THF 500

Hi-Flow® is available with or without pressure sensitive adhesive on the back. Thicknesses of different Hi-Flow® products range from .005” to .015”. NEDC die-cuts Hi-Flow® through conventional die-cutting equipment.

Thermally Conductive Tape

These thermally conductive tapes are essentially materials that are filled with thermally conductive fillers with tape on both sides to aid in assembly. One commonly chosen material in industry is Bond-Ply®. Bond-Ply® by Henkels’ Bergquist are double sided tapes with different reinforcements. Some of the benefits may seem obvious, but assembly can present a challenge – especially in custom cut thermal pads.

• Replacement to heat cured adhesives

Heat cured adhesives need certain setups that can be costly depending on the application. Having an alternative that is easy to assemble at room temperature can provided a great cost/benefit ratio.

• Replacement to screw/clip mounting

As we have discussed the challenges of thermal greases, even uses clips and screws can present challenges in certain applications.

Some common Bond-Ply products are below:

• Bond-Ply 100, BP100 aka BOND PLY TBP 850
• Bond-Ply 800, BP800 aka BOND PLY TBP 800
• Bond-Ply 400, BP400 aka BOND PLY TBP 400

NEDC offers die-cutting (converting) services for thermal pad materials. For more information on Hi-Flow materials please visit Henkels’ website.