Are Thinner Thermal Pads Better than Thicker Thermal Pads?

Choosing the right thermal pad thickness can affect devices’ performance and service life. The effectiveness of thin and thick thermal pads depends on your thermal management needs, operating environment, and more. This article compares thinner and thicker thermal pads to help you make an informed decision more quickly.

What is a Thermal Pad?

A thermal pad is a thermal interface material that uses high thermal conductivity to offer heat dissipation in electronic devices. It rapidly transfers heat generated by components during operation to a heat sink or the device housing, preventing heat buildup that could cause overheating and achieving high-performance operation.

It is typically made from silicone or non-silicone materials combined with additives such as aluminum oxide and boron nitride. Compared to thermal paste and more, thermal pads offer more options and are easier to install. They are commonly used in electronic devices, automobiles, battery management systems, and other applications.

Thinner Thermal Pads vs. Thicker Thermal Pads

Difference in Adhesive and Fill Performance

Adhesive and Fill Performance of Thinner Thermal Pads

To save installation space and better use in slim designs, thinner thermal pads typically have a more compact design. Thanks to their thinness, they offer better flexibility and can easily compress to conform to minor surface irregularities, achieving tight contact between components.

So, thin thermal pads are good for applications requiring tight tolerances and precise assembly, helping to achieve stable and efficient heat transfer in confined spaces.

Adhesive and Fill Performance of Thicker Thermal Pads

Thicker thermal pads are typically harder and more difficult to bend. So they can not effectively fill minor surface irregularities, but they are better at compensating for differences in component height. As a result, they provide better contact on uneven surfaces.

Additionally, for applications requiring enhanced adhesion, we offer sticky thermal pads with longer-lasting adhesion during prolonged thermal cycling.

Difference in Heat Dissipation Performance

For thermal pads of the same model but different thicknesses, their thermal conductivity is typically the same. However, thickness can affect the thermal pad’s heat dissipation performance by influencing thermal resistance and thermal impedance.

Heat Dissipation Performance of Thinner Thermal Pads

For thermal pads with the same thermal conductivity, thinner thermal pads have lower thermal resistance, which reduces barriers to heat transfer and enables more efficient heat dissipation. However, avoid choosing thermal pads that are too thin, as they may fail to fill the gap between the heat sink and the component, allowing air to enter. This actually increases thermal resistance and reduces heat dissipation efficiency.

Heat Dissipation Performance of Thicker Thermal Pads

Thermal pads work by increasing the thermal contact area and reducing thermal resistance. Although thicker thermal pads can better conform to irregular surfaces, they have longer heat transfer paths and higher thermal resistance, which typically result in lower heat dissipation efficiency. In practical applications, you should balance thickness and thermal resistance when making your selection.

Difference in Durability

Although thinner thermal pads offer higher heat dissipation efficiency, they are more prone to fatigue under high temperatures and prolonged thermal cycling, resulting in aging and deformation. Thicker thermal pads, on the other hand, have better stability at high temperatures and have a longer service life. Therefore, you should choose thicker thermal pads for products requiring high reliability and long-term use.

Difference in Seismic Resistance

Thanks to their good shock resistance, thicker thermal pads provide additional mechanical protection while dissipating heat. Therefore, you can use thicker thermal pads in applications prone to impact and vibration(such as automobiles and drones) to reduce component damage and extend the product’s service life. Additionally, they can reduce the noise generated by components while working.

Thinner thermal pads, however, offer less cushioning than thicker ones and are more advisable for applications with smoother operation.

Difference in Cost

Thinner thermal pads are typically less expensive and can be used for mass production and low-cost applications. They also provide high thermal conductivity for small gaps and smoother surfaces. Thicker thermal pads generally use more material and are therefore more expensive. However, they have a longer service life and offer better filling and compression properties, making them cost-effective. Whether thick or thin, thermal pads last longer than thermal paste and result in less maintenance cost.

Thinner Thermal Pads vs. Thicker Thermal Pads

When Should You Choose Thinner Thermal Pads?

Space-Saving Equipment

The thickness of thinner thermal pads is typically less than 0.5 mm. They take up less space and are lightweight, so they are the ideal choice for products with slim, lightweight designs. Additionally, they offer a high thermal conductivity-to-weight ratio, meeting the high heat dissipation requirements of compact products. You can use them in products such as smartphones, tablets, and smart wearable devices.

Smooth Surface

Thinner thermal pads are less effective at filling gaps than thicker ones and cannot effectively compensate for height differences between components. This can easily result in air gaps with extremely low thermal conductivity, hindering heat transfer. However, they provide excellent adhesion on smoother surfaces or those with minor irregularities, thereby improving heat dissipation efficiency.

High Heat Dissipation Requirements

Thinner thermal pads have lower thermal resistance, allowing heat to be conducted more quickly and from electronic components to the heat sink, and keeping the device within a safe temperature range. Some high-performance thermal pads, such as graphene thermal pads and carbon fibre thermal pads, typically offer thinner options.

Therefore, if you are selecting a thermal pad for high-performance devices such as CPUs, LEDs, GPUs, or power circuit boards, a thinner thermal pad is the better choice.

Application of Thinner Thermal Pads

Electronic Products

Thin thermal pads are the ideal thermal interface material for lightweight and compact electronic devices. Not only do they meet the lightweight requirements of smartphones, tablets, laptops, and other devices, but they can also handle their high thermal loads, achieving the stable operation of high-performance electronic devices.

Furthermore, they can efficiently assemble in high-volume production. You can also use them in wearable electronic devices such as smart glasses and watches.

Automotive Electronic Modules

Thin thermal pads can dissipate heat from automotive battery management systems, automotive electronics, and other components. They help maintain safe temperatures for battery modules during charging and operation, preventing safety risks caused by overheating and improving vehicle safety.

In automotive electronics such as autonomous driving systems, smart voice systems, and in-vehicle charging modules, thin thermal pads offer rapid heat dissipation, achieving smooth and reliable operation.

LED Lighting

LED lights are typically designed to be slim, and thin thermal pads meet these requirements while offering good heat dissipation performance. Thin thermal pads can be used in LED lighting fixtures to efficiently transfer heat generated by the LED chips to the heat sink, achieving continuous illumination and extending the life of the LEDs.

Communication Equipment

Thin thermal pads can also be used in 5G base stations, radio equipment, and other devices to reduce the heat generated by communication equipment under heavy loads. This improves the stability and accuracy of communication equipment and prevents signal interruption and distortion.

Medical Equipment

Silicone-free thermal pads are available, and they do not contaminate components and are safe for use in precision medical devices. Compared to thermal paste, thin thermal pads are cleaner and need less maintenance, so you can use them for medical imaging and measurement equipment to improve image and measurement accuracy.

You can also use them to achieve the continuous working of devices such as ventilators and monitors, preventing shutdowns caused by overheating.

How to Choose the Right Thermal Pad Thickness for Your Application?

Measure the Gap Thickness

Before selecting the thickness of a thermal pad, you should measure the gap between the component and the heat sink accurately. You should take many measurements to maximize accuracy, and it should not be a vague estimate. Before measuring, you should clean the surfaces to avoid errors that could affect the thermal pad’s installation and performance.

You can contact the supplier for professional measurement assistance to obtain more accurate data and detailed recommendations on selecting the best thickness.

Determine Your Cooling Needs

The thickness of a thermal pad affects its heat conductivity performance, so you should consider the product’s heat dissipation needs when choosing the appropriate thickness. If you are selecting a thermal pad for devices that require efficient heat dissipation, such as CPUs, high-power LEDs, or GPUs, a thinner pad can transfer heat more quickly. However, when choosing a thinner thermal pad, you must also make sure that it is thick enough to form a uniform and flat bonding line.

Select Based on Surface Flatness

When selecting the thickness of a thermal pad, you should also consider the surface roughness to achieve the best contact and maximize the thermal contact area. For smooth surfaces, you should select a thickness based on the gap between the component and the housing or heat sink, choosing the thinnest possible option to minimize thermal resistance.

For rougher surfaces, you should choose a thicker thermal pad to compensate for surface irregularities, getting tight contact and efficient heat transfer.

Considering Pressure and Compression

Once installed in a device, thermal pads are subjected to pressure, such as that caused by the housing and heat sink. This results in the thermal pad compressing. Therefore, when selecting a thermal pad, you should also consider the pressure exerted by the device and the pad’s compressibility.

For devices that must withstand higher pressures, you should choose a thicker thermal pad to prevent damage caused by excessive pressure. Devices with lower pressure do not need as much compression space, so a thin thermal pad is enough.

View the Manufacturer’s Data

Manufacturers of thermal pads provide technical specification sheets for different models, which include detailed information such as the material, thickness, thermal conductivity, compressibility, and range of applications. You can use these technical specifications to make a more informed decision. Some manufacturers also showcase application examples, and you can also contact their technical teams directly for advice.

FAQ

Common Mistakes to Avoid When Installing Thin Thermal Pads

• Uncleaned surfaces: Before installing the thin thermal pad, you must remove dust, water, and other contaminants from the surface of the component, housing, or heat sink. These contaminants can influence the thermal pad’s adhesion and reduce heat dissipation efficiency.
• Excessive compression: Avoid applying excessive pressure during installation, as this can cause the thermal pad to deform or even damage the components.
• Failure to inspect the installation: After installation, you should check the adhesion. If bubbles or misalignment are found, reinstall the product.

Can Thinner Thermal Pads Maintain Good Performance in High Temperatures?

This depends on the operating temperature range of the thermal pad you choose. Most thin thermal pads maintain good performance within the range of -50°C to 200°C. You should select a thin thermal pad suitable for your application. If the operating temperature is too high, it may cause the thermal pad to degrade more quickly.

Thin Thermal Pads vs. Thermal Paste

Both thin thermal pads and thermal paste are used for small gaps. Thin thermal pads are solid, pre-formed sheets, whereas thermal paste is fluid. As a result, thermal paste can better fill rough surfaces, achieving a thinner bond line than thin thermal pads and maximizing heat dissipation efficiency. However, thin thermal pads are easier to install than thermal paste and are less prone to pumping out or drying out during long-term thermal cycling, offering a longer service life.

What are Thinner Thermal Pads + Copper Shims?

This involves using thinner thermal pads together with copper foil. Although copper foil has extremely high thermal conductivity and quickly transfers heat generated by heating elements to the heat sink, it lacks the ability to fill gaps. Therefore, using it in combination with a thinner thermal pad increases the thermal contact area, resulting in more efficient heat transfer.

Can Two or More Thin Thermal Pads be Stacked to Fill a Large Gap?

You had better not use many thin thermal pads in a single gap. For one thing, this makes installation difficult and is highly inefficient in high-volume production. Furthermore, stacking many pads can result in uneven contact and increased thermal resistance, which can result in poor heat dissipation. If the gap is large, it is best to choose a thicker thermal pad.

Which Can Be Reused: Thinner Thermal Pads or Thicker Thermal Pads?

Neither thin nor thick thermal pads are reusable. This is because used thermal pads become compressed and may contain contaminants such as dust. Reusing them can result in high thermal resistance. In particular, adhesive thermal pads must never be reused, as their adhesive layer is compromised after use.

Final Thoughts

Thinner thermal pads perform well in applications with limited space, flat surfaces, and high-power devices. You can choose thermal pads from GALLOP INNOTEK for the right products. We also provide technical support and selection guidance to help you avoid project delays caused by incorrect product selection. Feel free to contact us at any time!