Increased performance in thermoplastics
For many years EJOT has been the market leader for self tapping screws for plastics. The EJOT DELTA PT® screw is a special fastener for reliable and trouble-free direct assembly into thermoplastic materials and due to its special thread forming zone it is also suitable for thermosets. A robust fastener with optimised thread geometry has been developed which offers a secure joint even under difficult conditions and in challenging designs.
Especially for applications in the automotive field the EJOT DELTA PT®
has proven to be a dependable fastener for direct application into plastics. The DELTA PT®
screw is currently used in several serial productions of various vehicles. The application areas range from head lamp casings, motor covers and applications in the car interior to intake manifolds and throttle valve connections which often have to withstand high temperature and pressure forces.
The “secret“ of the DELTA PT® screw is its special thread geometry. The flank geometry of this screw was optimised through consequent analysis of the material displacement during the thread grooving. The flank angle of the DELTA PT® screw enables a visible reduction of the radial expansion compared to conventional thread flanks of screws with 60° flank angle (e.g. sheet metal screws). The 20° or 30° angle respectively only generates a small radial expansion and a very thin-walled design can be achieved. Furthermore the thread flank enables an optimal material flow even with reinforced thermoplastics.
The ideal pitch of the DELTA PT® screw was determined through the well-balanced ratio of highest possible pretensioning force and small contact pressure on the plastic. A large flank coverage is reached even for smaller insertion depths due to the pitch. This results in a large cost saving potential for the user, since the respective screw-in depths can be designed much shorter.
Compared to the EJOT PT® screw the core cross section was also enlarged. This results in an increased tensile and torsion strength of the DELTA PT® screw. Therefore high pretensioning forces and tightening torques can be attained even for applications in high strength thermoplastics and thermosets. A higher dynamic stability is also reached through the new core profile.
The EJOT DELTA CALC® prognosis program is a sensible support during the design stage. This tool contains the parameters for DELTA PT® screw applications in dependence on the material and pre-hole dimension. Valuable time can already be saved during the design phase by using the DELTA CALC® prognosis program for the new layout of a component.