Andy Lampkin wrote a very important post, Membrane Switch Design Taboos, which briefly touched on a variety of design guidelines which we suggest. I’d like to underscore and expand on this topic, by providing the following case study. As the parts involved have not yet released, I will be using generic names.
I have recently built prototypes for two different companies, Company A and Company B, and both have switches and LEDs underneath an overlay. Company A came to GM Nameplate as the last step in their process. They had finalized their designs, and were already producing housings. As a final step, they asked for prototype membrane switches to display the product’s status and allow the user to interact with it. Their bezel, however, was far too small to accommodate the components needed. Although we stressed concerns regarding the strength of the parts, at their direction we produced a set of prototypes to fit their bezel. After delivery to Company A, during their testing, the overlays began to delaminate, and the circuitry to fail. While we employed high-strength adhesive, burnishing tools, and the like to try and increase robustness, the reliability of the parts still remains in question.
In contrast, Company B came to GM Nameplate as one of their first steps. Company B had an idea of how their interface should look, and by working with GM Nameplate, determined an attractive and robust solution.
The parts we provided Company A and Company B had no difference in cost. But while Company A must now choose between losing time and money redesigning their product, or risking failures in the field, Company B can proceed knowing their product will hold up without concern. If you need to design an interface, why not leverage GMN’s quick-turn prototype program and experienced design engineers?