Question: What is the typical flash tolerance for a silicone part?
Answer: Silicone has a relatively low viscosity compared to other TPE (Thermoplastic elastomeric) or thermoplastic. The silicone’s viscosity enables us to more easily mold micro parts, but it also presents a challenge with flash. The typical flash tolerance for a silicone part is .005”. However, the tolerance can vary widely depending on the individual application. For example, a simple non-medical gasket may have a flash tolerance of .025” because the priority of the gasket is to provide adequate sealant in its application. On other hand, micro silicone components of a catheter may have a flash tolerance as low as .001” or less because a couple thousandths of flash or more may irritate the patient when in contact with the patient’s body parts. In addition, larger flash is a potential cosmetic defect since the components are very small. Finally, the flash tolerance can affect the cost of a part; usually the smaller the flash tolerance is, the more expensive the part is. This is due to manufacturing and inspection challenges.