Silicone elastomer protects critical components

Two-comportment silicone elastomer enables a new technology to protect mission-critical electronic components from damage due to heat, shock and vibration.

Lord has provided a two-comportment silicone elastomer solution that enables a new technology to protect mission-critical electronic components from damage due to heat, shock and vibration.

"Heat and vibration are two of the biggest enemies of the electronics industry", said Lauren Groth, President of Ultimate Solutions - a Cypress, Texas-based firm.

"Even specially-designed electronics can have a meltdown when exposed to extremely high temperatures".

"And when you have sensitive electronics, it often doesn't take much energy in the form of shock or external vibration to cause damage".

Case in point is the protective case Ultimate Solutions had in development for use in oil field down-hole applications.

Because of the environment these cases endure, Ultimate Solutions sought a means to better protect the cases from vibration and heat.

As such, in 2005, Groth asked Lord Corporation, through distributor Krayden, to develop a product that offered high vibration performance and protection as well as thermal conductivity.

Building on expertise with existing technologies, Lord experimented with different mix ratios to find the optimal solution.

Prototypes were presented to Ultimate Solutions and then validated by testing conducted by the oil companies using the cases.

According to John Saxton, Lord Account Manager, the solution - Lord SC-320 - is a two-comportment silicone elastomer that provides excellent thermal conductivity, while retaining the other desirable properties associated with silicones.

It is a low-viscosity, easily pourable liquid that is ideally suited for electrical/ electronic potting applications.

It has excellent high heat performance, thermal shock resistance, and improved coefficient of expansion.

Further, Lord SC-320 has been formulated for flame retardancy and meets UL94V0 flammability rating at 6mm.

According to Edd Anthony, a Sales Representative for Krayden, with the proper elastomeric solution from Lord, Ultimate Solutions was able to launch Preforms - a patent-pending technology designed to extend the life of electronics deployed in hostile environments with excessive temperatures, shock and/or vibration.

The custom-made Preforms fit electronic components, assemblies and chassis.

Traditional methods of protecting electronics by potting and encapsulation often fall short, said Groth.

These techniques involve placing the component in a potting vessel, pouring a potting compound over it, and then curing the potting compound for a period that can range anywhere from one to 48 hours.

This procedure produces a component that's permanently encased in the potting medium.

"One of the drawbacks of potting and encapsulation is that they are labor-intensive procedures that can significantly increase the time and expense of manufacturing", said Groth.

"In comparison, Preforms can take just a few seconds to apply during the electronics assembly process, greatly reducing the time and cost involved".

"And, since Preforms can be easily removed, parts can be quickly serviced, calibrated, or replaced".

With potting and encapsulation, impurities on the electronics can prevent the potting compound from curing properly.

Although the resulting device may look fine from the outside, the interior may retain a pasty consistency.

This compromised physical structure diminishes the potting compound's ability to protect the electronics, and performance can suffer.

In contrast, with Preforms, one can physically inspect the protection during the assembly process.

Further, Preforms protect fragile components by surrounding them with minimal clearances that compensate for thermal expansion.

This can be accomplished in a fraction of the time required for potting and encapsulation protection, with less risk to the devices inside.

Once a component is repaired or replaced, its Preform can usually be re-applied and reused.

Ultimate Solutions uses mould-design software to create designs that maximise the performance of each Preform.

The technology is suitable for nonstandard thickness, or if clearance is required to accommodate fragile chips and components.

Preform protection includes both two- and three-dimensional geometries, and it can be used with a wide range of applications including circuit boards, sensors, detectors, battery packs and others.

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