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Greater flow lengths and lower pressure drop in the injection molding process are also key benefits.

Stephen Moore

February 21, 2018

3 Min Read
Heat and Cool tool technology improves surface finish of ABS/PC blend

Acrylonitrile-butadiene-styrene (ABS) polymer and blends supplier Elix Polymers reports that significant surface finish improvements are being achieved by using Roctool’s Heat and Cool technology to mold its Elix Ultra HH4115HI ABS/polycarbonate (PC) blend. The company recently completed a series of tests using this technology, carried out in line with its strategy of providing tailor-made solutions and service to companies processing its specialist materials.

Superior surface replication, longer flow length, and lower pressure drop can be achieved with a combination of Roctool and Elix’s ABS/PC grade.

“We are operating in a highly competitive market, so it is important for us to go the extra mile to demonstrate to our customers how they can get the most out of our materials,” says José Pedro Abad, business Development Manager Automotive at Elix. “We wanted to quantify the possible improvements – in terms of part aesthetics and also processing performance – using Heat and Cool technology. We chose to use Roctool induction heating technology to characterize our innovative ABS/PC blend Elix Ultra HH4115HI, a leading Heat and Cool technology (H&C), in order to expand the already wide range of applications.” continues Abad.

The material characterization is part of Roctool’s ongoing effort to further develop its High Definition Plastics material database which is designed to help OEM’s achieve exceptional part quality and increased performance” comments 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. Mold 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 demolding temperature to minimize any increase in total cycle time.” continues Mathieu Boulanger.

By heating the mold temperature above the glass transition temperature, an excellent cavity surface replication is achieved–even for surfaces that have the finest laser-etched grain structures – as well as the elimination of weld lines and sink marks. It therefore reduces or even eliminates the need for painting or in-mold 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.

To characterize the innovative ABS/PC blend Elix Ultra HH4115HI under H&C conditions and according to the HD Plastics process, Roctool determined the surface replication for the following three surface structures: Chemical grain; electric discharge machining (EDM) grain; and laser grain as well as improvements in gloss and color. Besides surface replication, flow length studies were also carried out.

“HD Plastics characterization highlighted the improvement made by using Roctool technology with surface quality improved by the level of gloss and the black intensity. Indeed, Roctool’s technology allowed a reduction of the color lightness and we obtained a ‘piano black’ part with a perfect surface finish.” says Abad. In addition, replication of the textured surface was improved by over 50%, and there were significant improvements for each type of surface structure, especially with low roughness.

The final HD Plastics characterizations are based on the study of the flow using the Spiral mold for thicknesses of 1 and 1.5 mm. This study shows substantial improvement using Roctool technology versus conventional technology in terms of pressure drop reduction, which is up to 60%, and flow length, which rises by up to 100%.

“Elix Ultra HH4115HI ABS/PC is now included in the HD Plastics material database based on the excellent results demonstrated by the characterization. The outstanding properties of this material will help us select Elix Ultra HH4115HI ABS/PC as an excellent candidate for upcoming projects with OEM’s.” explains Jose Feigenblum, Roctool’s CTO.

Elix Ultra HH4115HI ABS/PC, which was introduced just over a year ago, has several advantages over a PC/ABS (which contains less ABS and more polycarbonate). For example, it is around 5% less dense, it has lower emissions and odor, a higher flow rate, and higher impact strength. It is suitable for crash-relevant parts such as interior trim and parts that may be subject to knee or head impacts, as well as for exterior applications such as pillar covers and other painted side moldings.

About the Author(s)

Stephen Moore

Stephen has been with PlasticsToday and its preceding publications Modern Plastics and Injection Molding since 1992, throughout this time based in the Asia Pacific region, including stints in Japan, Australia, and his current location Singapore. His current beat focuses on automotive. Stephen is an avid folding bicycle rider, often taking his bike on overseas business trips, and is a proud dachshund owner.

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