RF Welding of Thermoplastic Polyurethane
To accomplish a reliable transition between two TPU differential durometer components the primary objective is the application of optimized localized process temperatures. Generally speaking, this is accomplished when polymer properties are allowed to exhibit an even distribution of amorphous hard and soft segment in the molecular architecture in process, see Figure 3.0.
Although normalization of many TPE’s will exhibit similar results, they typically are not as dramatic or predictable as TPU results, see Graph 1.0. Additionally, any thermoplastic processing which includes what otherwise would be considered “normalizing” should be integrated into one single process when ever possible.
In either case, a seamless transition between components is desirable as is the superior joint strength and conservation of
individual component characteristics such as their durometers. Using a process that manages the energy required to heat and cool is the goal of this comparison.