Wear of die materials in full scale plastic injection moulding of glass fibre reinforced polycarbonate

Abstract

In this study an experimental methodology to study surface wear of injection moulds on a full scale polymer injection moulding machine is developed. A comparative study of four different tool materials for mould cavities is carried out in situ. The polymer injection conditions (geometry cavities, machine settings, polymer) are chosen in order to accelerate the degradation of the mould cavity surface. The reinforced polycarbonate resin Lexan 341R-739, containing 40% of weight of short glass fibres, well known for their abrasive character, was injected with jetting and normal injection conditions. Jetting conditions implies high pressure and velocity of the injected resin. The die wear is discussed in relation to the polymer flow conditions and the die materials.

The Mechanical and Optical Properties of Injection-moulded PMMA, Filled with Glass Particles of a Matching Refractive Index

“…The roughness of the surface increases with smaller particle size due to the increasing number of particles. A rough surface is a commonly known issue with glass-reinforced polymers 28,29 and is assumed to be the main reason for the high haze values at identical refractive indices in this case. The specimen between glass panels and RI oil, use to compensate for the surface roughness, exhibits a haze reduction of 58% with a matching RI at 400 nm.…”

Micro metal injection molding (MicroMIM)

“…Micro-machining and micro-discharge machining are currently the most popular and most established methods (Brinksmeier et al, 2008). Finally, two or more structuring methods can be combined to manufacture (Bergstrom et al, 2001;Schneider et al, 2005) describes experiments performed in special test stands, which compared mold insert materials according to their respective wear resistances. It turned out, rather unexpectedly, that rates of wear are lowest for materials of a lesser hardness, for example nickel, while being highest for dispersion-hardening steels whose precipitated grain particles are virtually washed away by the action of the feedstock as it flows past (Schneider et al, 2008).…”

Investigation and characterization of Stellite-based wear-resistant coatings applied to steel moulds by cold-spray

“…Surface degradation of the mould cavities is essentially due to the inflow of polymers and ejection of the solidified plastic parts. This surface wear depends on the type of polymers, glass content and process conditions [1]. Glass fibres contact with the cavities surface during both filling and ejection leads to scratches, making them rough enough to deteriorate the appearance of the moulded parts.…”