The EJOT DELTA PT® screw is a development of the PT screw, and the result of years of hands-on experience of screw fastening in thermoplastic materials. As a rugged fastener it delivers superb performance, even under extreme conditions of use.
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The special thread geometry, which is the result of a thorough analysis of material displacement during thread-forming, allows the formed plastic material to flow off in an optimal manner.
Self-tapping fasteners for plastics are ideal for thin-walled, flat construction methods. Their use can lead to material savings and shorter injection moulding cycle times. Taking into account the overall fastening costs for a component, self-tapping fasteners provide significant potential for savings.
There are many good reasons for using our products.
Strength and options.
Point by point.
Small flank angles reduce radial stress, allowing for thin-walled construction methods.
A perfect fit, through optimised material flow during assembly.
The optimised pitch minimises the possibility of the screw working loose.
Quick to install but very durable, thanks to the use of heat-treated steel PT 10.
The enlarged core cross-section increases the strength of the screw so that high preload forces and tightening torques can be achieved even in high-strength thermoplastics.
In lightweight construction every gram counts. In contrast to conventional joints, shorter screws and/or smaller diameters can be used.
Lower inventory costs through the use of standard parts.
The assembly of EJOT DELTA PT® screws is done with state-of-the-art screwing machines. As visible in pictures 1 to 3 the screw is positioned and screwed in. The screwdriving unit switches off at a given tightening torque.
The recommended screwing speed is 500 rpm. To save assembly time, it can be increased to up to 1,000 rpm for engineering and high-performance plastics.
The design of the screw-in tube in conjunction with the clamping part has a decisive influence on the durability of the screw connection. The EJOT DELTA PT® thread was developed especially for direct screwing of thermoplastics.
The combination of special thread pitch and formed flank angle enables the realisation of a particularly efficient connection.
The EJOT DELTA PT® screw enables reliable connections in the field of direct screwing in plastics. Some constructions require thermosetting plastics which, due to their hardness and brittleness, have special demands on direct screwing.
Modified thread flanks are required to enable direct screwing into these particularly demanding materials.
With the thread form DS (DuroSet) EJOT has responded to these demanding conditions. The EJOT DELTA PT® DS screw has special grooves on the proven EJOT DELTA PT® thread geometry, which significantly support the cutting process in the nut thread. These grooves are particularly pronounced at the screw tip and run out towards the screw head. The thread forming zone enables a low insertion torque and a high overtorque.
In order to achieve the highest possible torques with these hard thermosets, a screw-in depth of 2.5 x d is recommended.
If both thermoplastic and thermoset components are to be screwed together in assembly and identical screw dimensions are to be used for cost reasons, the DELTA PT® DS screw, with a slightly lower torque level, can also be used for thermoplastic components.
The EJOT APPLITEC is at your disposal for component tests.
When it comes to designing components for direct screwing of thermoplastics with steel screws, it frequently occurs that the strength of the screw-in material is significantly lower than the screw material itself, especially with standard thermoplastics.
For the EJOT DELTA PT® P screw the high performance plastic PPA GF50 is used as screw material. This enables a self-tapping screwing into standard thermoplastics. Thus a light and electrically or thermally insulating screw connection can be realised.
