The Trelleborg Corporation in El Segundo designs and manufactures high precision seals for the aerospace and automotive industry and a small group of IET members and guests were fortunate enough to get a tour of this facility. With much of the tooling and manufacturing being carried out by technicians with a lifetimes experience on the tools it was inspiring to see what can still be done with minimal automation.
The products manufactured on site are used in aircraft systems such as landing gear, hydraulic units and other subsystems which have rotating or reciprocating elements using working fluids or lubricants ranging from 7XX series passenger aircraft through to 4th and 5th generation fighter aircraft.
To meet the performance requirements of the varied conditions that the components are required to work under, the principal raw material is PTFE (Teflon) powder in grades tailored to the application and in some cases loaded with dyes and glass or ceramic powders. This allows seals ranging from a few millimeters to hundreds of millimeters in size to be made that can survive temperatures ranging from about -70 to 200 deg. C. depending on the grade of PTFE used.
Attendees were shown the manufacturing process from start to finish, with the storage of the PTFE powder which in turn is moulded and extruded by means of heat and pressure into rods, tubes and other shapes or skived into tape. Some of the polymer components are machined into shapes which require springs to maintain the seal contact. The springs are custom made on site as well and the attendees saw where strips of metal were shaped, cut and welded to make springs.
Throughout the manufacturing process an attention to detail and a comprehensive set of processes to ensure all materials are subject to very comprehensive inspection, tracking and documenting to ensure demonstrably tight adherence to specification and a clear audit trail in case of subsequent problems.
Overall this was a wonderful opportunity to witness the production of high quality, high-value products.