Linear sensors help stretch bath manufacturers' profits. Penny & Giles sensors are fitted to a new machine that is helping bath and shower tray manufacturers save thousands of pounds in material cost. Preston Associates of Kincardine in conjunction with Dundee based Marcoh Engineering, are revolutionising bath and shower tray manufacturing with their new Stretch-Form vacuum forming machine, which produces material savings of up to 50% by stretching acrylic sheets in two planes prior to manufacture. Explains Ron MacDonald of Marcoh Engineering: “Using conventional vacuum forming machines, manufacturers can waste significant amounts of expensive acrylic because they have to cut standard bath or shower tray-sized pieces from the large sheets supplied by the material suppliers. “With Stretch-Form, manufacturers can cut the large acrylic sheet into equal portions with no waste and stretch the material to suit standard bath and shower tray sizes. Another benefit of the process is that stretching increases the strength-to-weight ratio of the acrylic.” The Stretch-Form is fitted with Penny & Giles SLS320 sealed linear sensors on all three of its axes to provide accurate position feedback for the stretching and forming processes. The X and Y axes ensure that the correct amount of ‘stretch’ is applied for each bath or tray size, allowing the machine to be accurately programmed to process the acrylic sheet from pre-stretched to post-stretched state. Another SLS320 is fitted to the Z-axis, which controls the ‘draw’ that determines the rim size of the bath or shower tray. Marcoh Engineering also manufactures a range of ovens and trimming machines used in the manufacture of acrylic baths and shower trays. The ovens are used to heat acrylic sheets to 180ºC ready for vacuum forming. After forming, baths and shower trays are reinforced by spraying with GRP, cured and then finished on the trimming machines. Trimming machines are fitted with a Penny & Giles SLS190 sensor. Feedback from this sensor is used to verify the position of the cutter relative to a revolving trimming table. Commenting on the choice of sensors Ron MacDonald says: “We had used Penny & Giles rotary encoders until the new SLS sensors were introduced. SLS320s are ideally suited to the working environment of our machines, which is why they were specified for the new Stretch-Form.” He adds that the units are very competitively priced and Penny & Giles provides excellent product support and service. The SLS320 features IP66 sealing as standard and is supplied with an industry standard connector that enables it to be easily designed into existing and new equipment. It has also successfully completed almost 106 million strokes as part of a life cycle test. Each test cycle comprised two strokes - 25mm out, 25mm back - and the 52,891,471 cycles covered by the test was the equivalent of more than 2600 kilometres - approximately the distance from London to Istanbul! _________________________________________________________ For more information contact:- Penny & Giles Controls Ltd. Tel: +44(0) 1202 409409 E-mail: Website: September 2001

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