Once the gasket material is chosen, it may be necessary to select an adhesive that will work with it. An adhesive may be used to hold the gasket in place for sealing and compression. There are many adhesive types to consider, including:
Gaskets are used in many industries and applications.
Electronics: Within the electronics industry, there is a strong demand for gaskets that provide EMI/RFI shielding. In one example, gaskets made from conductive elastomers are used for both environmental and EMI shielding. In another example, gaskets help seal handheld communication devices to protect sensitive LCD screens and associated electronics from temperature, dust, and especially moisture ingress.
Transportation: Pressure sensitive adhesive (PSA) gaskets can provide a range of capabilities attractive to the transportation market. PSAs can bond to dissimilar materials, work well with lightweight yet sturdy low surface energy (LSE) plastics, and provide the flexibility to deal with vibration.
Medical: EMI gaskets are a mainstay of the medical device industry. Conductive elastomers are common, with a silicone elastomer filled with electronically conductive particles, such as carbon, nickel, nickel-plated graphite, silver-plated aluminum, silver-plated copper, nickel, glass, or pure silver.
Partnering with a converter
During gasket design, a design engineer may often turn to a converter for assistance in selecting the gasket material, as well as the appropriate adhesive. The converter may have a test lab where materials and adhesives can be tested and characterized to meet design specifications. In addition, the engineer will look to the converter for advice on how to best manufacture the gaskets cost-effectively to fit into an assembly process.
Depending on the material used and the number of pieces being made, the converter may suggest water-jet cutting, computer numerical control diecutting, or laser diecutting. Kiss cutting could also be used to cut the gasket and adhesive while leaving the liner intact, so the gaskets can be packaged in rolls. Slitting, laminating, and kitting will also be part of the services the converter can offer.
Working with an experienced converter is critical. For example, an experienced converter will know how much a soft material like an elastomer foam will compress and how much it may move during the diecut process, and will make the appropriate adjustments.
Craig McClenachan is Vice President, Fabrication and Assembly, with Fabrico.