Exceeding IPX7 standards, reducing costs
The test was created and executed by Sean Riskin, Director of Engineering for the Global Electronics Group at Stanley Engineered Fastening. Afterward he created a revealing study that includes his findings that tested nearly a dozen fastener configurations of various brands to find the best solutions that meet or exceed IPX7 standards.
Most sealants for micro fasteners are a nylon or Teflon-based substance, and there are only two options for applying the protection. Manufacturers either seal the threads, or seal underneath the head of the screw. Both have advantages and disadvantages.
Sealing just the threads may not protect the multiple layers of components that are in a typical fastened joint. This is because the components being fastened together are in the path of water before the protective sealant. Sealing under the head is preferable because it is the first barrier against moisture. Yet this is the method that, in some cases, results in an overspray and discoloration caused by the application process.
“You don’t want to spend double or triple the price on a fastener and not have it look cosmetically pleasing,” Riskin says. “In a sense, electronic manufacturers are struggling with a three-way battle. Function versus beauty versus cost.”
Also, the sealant is what creates prohibitive costs because it must be applied to every single unit as a secondary operation, forcing major manufacturers to spend upwards of tens of millions of dollars annually just on micro fasteners alone. But what if the sealant could be eliminated from the equation? That’s easier said than done.
The sealant creates a water and dust barrier and, in addition, the screws must have an anti-vibration feature applied so that it won’t loosen and back out during normal use of the device. Both features are 2nd and 3rd operations that are very costly to the overall price of a fastener.