Membrane Switch Venting
In the early 80’s, we were working with an appliance OEM on a microwave membrane switch program, which was having electrical short issues. We analyzed the problem and solved it by putting air channels beneath each key and having those channels go to an internal or external edge on the part. This design has come to be known as the membrane switch venting design and it is commonly used in almost every membrane switch today.
Two-Layer Tail
In the late 1980s, a customer came to us with a cost reduction plan they wanted to implement on their electronic control. This plan would reduce the protection against silver migration in the silver crossover conductors in our membrane switch, which could be problematic. As a solution, we got creative and came up with a two-layer tail that eliminated the need for silver crossovers in the membrane switch circuitry. There were other multiple tail membrane switches in the marketplace, but they required added cost for connectors for each of the tails. Our design placed the two tail layers directly on top of each other in a manner so they could plug into one connector. This gave the necessary robustness against the potential for silver migration in a cross over conductor—and still only required one connector for the two tail layers. It’s a membrane switch design that still is used today throughout the industry.
Bent-layer IML
As the one piece advantage of In Molding a formed decorative label became more common, the cost of tooling for forming and 3D hard tool die cutting of the decorative overlay became an obstacle for low volume products. If the In Mold decorative overlay could remain flat, there was not a tooling issue. But when the decorative overlay had to fit the 3D contours of the mold cavity, tooling for forming and die cutting the overlay was a significant factor. To solve this problem on lower volume product lines, we came up with a heat-bending process that required no form tooling and did not need a matched metal hard tool for die cutting. We called this design “the bent-layer IML” and it is used successfully today on lower volume IML product lines. It keeps the tooling cost for the bending operation very low and does not require 3D hard tooling for die cutting.
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