Dr Boy, German injection moulding machine maker, says it has improved the processing of silicones with an 8 mm-size silicone unit on its Boy XS machine. It will present its latest technology at the German Rubber Conference in Nuremberg, that will take place from 2–5 July 2018. The machine will be shown producing small-size LSR-sealing rings, which will cross-link in the mould under the influence of UV-light in a short time. “With this kind of application long flow channels or thin-walled components do not pose a problem,” says the company.
The lower temperature level during the processing paves the way to exploit additional areas of use and product applications with new material additives. For example, in the medical field, additives can be processed that normally cannot be exposed to high temperatures for a longer period of time.
In cooperation with the University of Kassel, the company EMT Dosiertechnik and Boy, a sealing ring mould for this process has been optimised for the UV-cross-linking in the mould. The transparent mould cavities are surrounded by a UV-lamp with precisely defined radiation. Only when the radiator is switched on the cross-linking of the two-component silicone in the filled mould will start.
The small 8 mm screw-piston-plasticising-unit of the Boy XS reportedly offers a high dosing accuracy at smallest shot volumes for the micro injection moulding of silicone. Due to the extremely small mass volume in front of the backflow valve and a special micro-valve gate nozzle from Emde Industrie-Technik, the processes are said to run precisely and clearly defined. Both, the quality and the consistency of the components are getting more precisely. With the application demonstrated at the DKT, the injection-moulded parts with 0.06 cm³ shot volume show a high reproducible-accurate weight constancy, says Boy.