Seeing Red in the WPS Potting Shed

With more than 20,000 units a month transiting the WPS resin encapsulation process, Hastings-based contract electronics manufacturer, Wilson Process Systems (WPS), is rightly considered an expert in the field of environmental protection. Eighteen variants of PCB undergo encapsulation using Black Polyurethane, Clear Polyurethane and UL-approved Grey Silicone at WPS, using approximately 30,000Kg (30 metric tonnes) of resin per year. But now the company is adding a new material. Tim Wilson, joint MD at WPS, points to the multiple solutions already available for a varied range of PCBs where protection is required for vibration, location or environment, using the existing polyurethane of silicone resins. “We have now had requests from customers for a more cost effective UL approved resin – and we’re happy to oblige,” he says. In fact, the process engineering team at WPS has tested and accepted a Stobicast L780 material. Stobicast L780 carries the prestigious UL 94 V-0 ‘self-extinguishing’ rating together with an approved Relative Temperature Index, RTI, for both mechanical and electrical of 130°C. The material also fulfils the requirements of the Household Appliances Standard IEC 60 335. “We’re very happy with the material and will be using L780 for specific encapsulation work from now on,” says Wilson. The new material is a distinctive red in colour, making it easy to identify the old from the new. As a result of increasing customer demand for encapsulation, WPS’s production team is planning to use even greater volumes of the new material through 2012. “We expect to get through 3,000 Kg (3 metric tonnes) this year,” Wilson claims. WPS has also invested in a new static-mix, gear-pump mixing system from specialists Liquid Control Ltd to mix and dispense the Red UL-approved resin.