Thermal Paste vs. Thermal Pads

Managing excess thermal energy (heat) is a significant aspect of today’s electronics design and manufacturing processes. Balancing design concepts and production realities often have engineers struggling to find the most optimal approach.

While heat sinks or other mechanical components help keep electronics temperatures at a minimum, the thermal interface materials used to couple these components to other electronics also play an important role. As the trend for thinner, smaller devices continues, thermal interface materials are often an integral resource to dissipate excess heat. 

Thermal interface materials (TIM) in pad form have typically been the most common for electronics manufacturing, comprising the bulk of the total TIM market. Pad TIMs are available in various types including thin films, thicker gap fillers and phase change materials. These pads are typically cold-applied using a manual process and/or a light adhesive to help adhere the pad to the component - requiring no special tools or equipment.

The simplified application process with themral pads is often offset by high manufacturing costs due to the manual application labor process and custom die-cutting required for each pad in the device. In some cases, there could be as many as 20 or more different sized thermal pads for one device. As redesigns occur to address changes in the market, the costs involved with creating new pad sizes can be significant – impacting the profitability and viability of multiple device redesigns.

In addition, most TIM pads have deflection limitations. Assembly workers must avoid potential fracturing or shredding of TIM pads that could lead to poor performance and possible product recalls.

The alternative to TIM pads are dispensable thermal interface materials in a variety of forms, including non-curing compounds, adhesives, encapsulants and gels.

Manufacturers using dispensable TIMs typically experience significant cost savings as a result of the following:

• labor and human resource costs are dramatically reduced as the material supply and dispense process is typically automated 
• costs associated with creating multiple custom TIM pad sizes are eliminated with one TIM material SKU and custom dispense capabilities 
• additional engineering and material costs from basic device redesigns and changes in TIM pad sizes are eliminated 
• accurate TIM dispense systems (once optimized) virtually eliminate excess material resulting in significant long-term material savings

Since most electronics manufacturers are usually familiar with a manual pad application process and are typically risk-averse, there is an understandably low comfort level with dispensable thermal interface materials. The general perception is that all dispensable products are messy and difficult to control – ultimately leading to material handling challenges.

Couple this with limited experience dispensing fluid materials and a minimal knowledge of fluid dispensing equipment, process engineers and operations managers are fearful of poor manufacturing processes – resulting in inaccurate TIM application, downtime and reduced throughout.

Stories from the early use of dispensable TIMs have likely played a part in creating negative perceptions. When dispensing fluid materials, especially TIMs, the challenges with viscosity and dispense accuracy are not easily resolved. Whether concerns center around potential rework, cleanliness concerns or the requirements of a particular application, these misperceptions make manufacturing challenges seem insurmountable.

For electronics manufacturing, long-term success rates hinge on developing the right process. Shifting from pads to a dispensable TIMs is no exception. Manufacturers are simply looking for confirmation that a new process involving automated fluid dispense will work.

In most cases, successful processes start with a productive collaboration of multiple subject matter experts. When transitioning to dispensable TIMs, it is critical to find the right outside partners that provide a true partnership experience and ongoing support to guide manufacturers through the process of change. 

Since budgets and resources are always tight, a successful collaboration between the material supplier and dispensing equipment provider is paramount. By working together in an initial planning effort, these partners can conduct adequate dispensing trials, work through experimentation scenarios and provide process data to help electronics manufacturers identify and refine a successful process.

Since material suppliers may prefer to stay neutral regarding equipment manufacturers, finding the right partnership may take time to vet out possible partners. Another challenge stems from the typical configuration of automed dispense equipment.

Most automated fluid dispense solutions are a mash-up of different products and technologies for the supply, dispense, XYZ motion table and motion software. This requires manufacturers to deal with multiple suppliers for the set-up and ongoing maintenance of the automated fluid dispense equipment. 

For electronics manufacturers looking to move from TIM pads to dispensable TIM materials, UniXact by Graco is the only end-to-end automated fluid dispense system on the market utilizing all components, XYZ motion and software from one source.

Graco has been setting the worldwide standard for fluid management technology since 1926. We have the experience and material supplier relationships to collaborate and figure out how to accurately dispense TIMs or other sealants and adhesives for a variety of electronics manufacturing applications. We focus on delivering the best industrial manufacturing customer experience by working with our customers and their material suppliers to help troubleshoot, test and find solutions to solve problems other equipment manufacturers can’t. 

To learn more about how Graco can help accurately dispense TIMs to control excess heat with accurate, reliable precision thermal interface dispense, visit UniXact.