Surface scrutiny

Louise Smyth

Elix Polymers says important improvements to surface finish are being made by using Roctool’s heat and cool technology to mould its Ultra HH4115HI ABS/polycarbonate blend. The company recently completed a series of tests using this technology.

"The material characterisation is part of Roctool’s ongoing effort to further develop its High Definition Plastics material database” commented Mathieu Boulanger, Roctool CEO. “Roctool’s H&C can have significant effects on surface quality, it also helps to eliminate evidence of weld lines and flow marks. The mould cavity surface is heated very quickly up to temperatures that can exceed 200°C just before injection. The surface is then cooled quickly, to achieve the necessary demoulding temperature to minimise any increase in total cycle time.” 

By heating the mould temperature above the glass transition temperature, excellent replication of the cavity surface is obtained – even for surfaces that have the finest laser-made grain structures. It therefore reduces or even eliminates the need for painting or in-mould decoration. Furthermore, shear stress in the melt is reduced which can have an important effect on the mechanical properties of the part and thinner walls.


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