Spin Welding of Plastics

Spin welding is a simple, fast, and reliable process. The key parameters are rotational speed, axial pressure (both during heating and forging), and weld time. The process can be broken down into four phases: orientation, pressing and spinning, welding, and cooling/forging. The heat is highly localized to the joint interface, resulting in minimal distortion of the parts. The joint design is critical; it often includes features like shear joints or tongue-and-groove designs to align the parts and contain the molten material, which helps create a strong, hermetic seal.

This method is suitable for most thermoplastics, both amorphous and semi-crystalline. Its primary limitation is the geometry of the parts; at least one of the parts must be circular or have a circular axis of rotation at the joint. The process also produces flash (expelled molten material), which may need to be removed depending on the application’s aesthetic or functional requirements. Due to its speed and simplicity, it is well-suited for high-volume, automated production.