A Tier III manufacturer of products for the powersports industry approached Tramonto Circuits to manufacture a flexible heater used in thumb throttles on snowmobiles, ATVs and UTVs. Their current supplier had become nonresponsive, causing significant fabrication and shipping delays that affected production timelines.
The Challenge
The flexible heater produced by the current supplier had a unique design that consisted of a Kapton® flexible heater (polyimide) and an aluminum heat spreader with a silicone layer in between. The customer supplied us with their design specifications and a sample flexible heater.
We discovered two challenges upon review of their submission. Though the specifications were clear, our engineers were unable to determine the types of coating used to adhere the silicone to the polyimide flexible heater and aluminum backing.
Another challenge was that silicone is not intended to be laminated to polyimide and does not accept the material well. For this reason, most flexible heater designs consist of either a silicone flexible heater or a Kapton® flexible heater, which is then adhered to a heat spreader.
Despite these obstacles, we were committed to creating a robust, reliable, and repeatable flexible heater for powersports products.
Prototyping and Testing Lamination Methods
Discovering a solution required multiple rounds of prototyping and testing by the customer and Tramonto Circuits. The timeline to figure out a solution was tight, as the manufacturer needed to have their products ready in time for the peak season for people purchasing snowmobiles.
The first flexible heater prototypes were successful in adhering silicone to the aluminum heat spreader; however, additional testing revealed that the silicone layer easily peeled away from the polyimide material.
In the second round of prototyping, we used a different epoxy between the silicone and polyimide layers. Tramonto Circuits conducted a peel test in addition to our typical quality testing and discovered that once again, the two layers easily separated.
It was at this point that we decided to contact our raw material manufacturer to discuss the issue of permanently adhering silicone to polyimide. Their recommendation was to use two separate finishes on either side of the silicone layer. This adjustment required additional design specifications and fabrication instructions to indicate which side of the silicone should be laminated to the polyimide flexible heater, and which side was coated with a different epoxy for the aluminum heat spreader.
Final Testing and Results
Quality inspection tests conducted by our engineers and the customer confirmed that the third prototype satisfied all requirements for proper adhesion and robust assembly. With final approval, we proceeded with fabrication. The heaters were produced on large sheets to comply with the customer’s internal manufacturing processes.
Partnering with the customer and our materials supplier resulted in a well-documented, repeatable design meeting the required specifications. The project’s success resulted in a continued partnership with the Tier III manufacturer.
Our Commitment To Design for Application
Tramonto Circuits places every flexible heater design submission through a Design for Manufacturability (DFM) assessment and conducts internal testing to produce high-quality, repeatable circuits and flexible heaters.
There are situations where our engineers might suggest alternatives upon the discovery of potential design issues. However, we believe in the importance of designing for the customer’s application rather than making design recommendations to fit our prototyping, testing, and fabrication processes.
With a historical quality ratio of 99%, we are dedicated to delivering technologies that exceed expectations. Contact us to discuss your flexible heater project with an engineer.