Thread forming screws designed for plastics

Kevin Moorcroft, Managing Director, explained: “Thread forming screws for plastics are easily inserted into drilled or moulded holes in thermoplastic materials where they deform the material to provide optimum fastening force superior to standard self-tappers. They are especially useful in the manufacturing production environment where automatic feed can be employed to greatly speed the assembly process. Thread forming screws eliminate the need for nuts or inserts, so reducing piece part costs, labour costs and process costs.”

There is a range of thread geometries associated with this type of screw, this is to allow for their use with different component materials and design features. For example, if required for insertion into thinner walled, harder plastic, mouldings it might be advisable to try a trilobular thread variant which tends to reduce the risk of burst out. Of course the choice of hole diameter can be critical and we at Challenge can advise on both screw selection and suitable hole diameters.

Head formats include countersunk, pan, and flange types with cross recess or multi-splined (star) drives. Typical materials include hardened steel with a zinc and clear passivate finish or in some instances black finishes can be available, also stainless steel.