TH inserts are recommended for thermoplastic applications. Their geometric shape and sharp pointed barbs ensure swift installation and complete flow of material to encapsulate the insert, providing ultimate resistance to torque loading and maximum tensile strength. Due to the elimination of installation stresses by use of heat or ultrasonics the wall thickness of bosses can be reduced to prevent any shrinkage witness on the opposite face of the moulding. If however this insert is used for pressing into plastic we recommend the use of thicker walled bosses to absorb the resulting hoop stresses. These stresses are minimised by the vane type barbs relaxing during installation, only to become firmly embedded into the substrate due to the sharpness of the points following installation. Subsequent application of loading increases the penetration of the barbs and therefore the performance. We recommend testing to ascertain the optimum boss size for press in applications.
All information is given for guidance only and designers should satisfy themselves as to the suitability of the specification by requesting samples
