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A manufacturer of dip moulded rubber and latex products has upgraded a semi-automated line to full automation using linear actuators from Parker-Origa, making the most of existing equipment while maintaining the flexibility to produce a huge range of goods. Bristol-based Precision Dippings Marketing Ltd had an existing transfer and handling system feeding the dipping tanks, which they wanted to retain.
They called in consultant engineers from Parker-Origa to work with them designing and developing a system to dip the moulds or forms into the tanks.
“Essentially, the need was to vertically lower the moulds into the tanks, then lift them out again,” says Parker-Origa’
“It was clear that we’d need an intelligent controller, and Precision Dippings were keen to retain the transfer system controller, so we had to interface to that too.”
Parker-Origa make a range of pneumatic and electrically driven linear actuators, so Nigel’s first job was to select the one that would be best suited to the job. Because it was a harsh working environment, a totally enclosed solution was desirable and after due consideration a suitable electric actuator was proposed.
The OSP-E range of actuators was identified as ideal; these are robust and self-supporting, although in this case they were fitted with a guide to ensure precision motion. They can be fitted with a belt or screw as the internal drive mechanism, with a trapezoidal screw being chosen for the dip moulder because there is no back driving. A range of motors can be fitted to the OSP-E. In this case servos were chosen for the vertical axes, as they are the best option for precision motion control options.
Actuators were also used on horizontal axes to transfer the moulds to and from the dipping tanks. These were powered by stepper motors, because the precise accuracy of servos was not necessary and their open-loop control simplified system design and installation.
Nigel again: “The vertical dipping motion has to be programmable for each type of product, so we needed an intelligent controller for that. The horizontal transfer movements are not so precise, but they can be complex to account for the need for different dipping patterns. Also different production volumes and speeds are addressed by using one, two or three tanks in parallel; so sometimes the lines are each handling different products. “We retained the original controller on the existing handling system, so use signals from this to initiate sequences on the new controller. Its actually quite an elegant solution, and was the way we minimised disruptionto production during installation.”
Precision Dippings currently use the new system on a 14 hour working pattern, but it is capable of running 24 hours a day if necessary. Products made include seals for divers’ dry suits, boots for vehicle gear levers, industrial seals, medial devices and consumables such as condoms and surgical gloves. Product quality has improved as a result of automation, while productivity has increased so much that Precision Dippings is able to take on considerably more business
ORIGA is a division of Parker Hannifin Corporation.
With annual sales exceeding $12 billion, Parker Hannifin is the world's leading diversified manufacturer of motion and control technologies and systems, providing precision-engineered solutions for a wide variety of commercial, mobile, industrial and aerospace markets. The company employs approximately 62,000 people in 48 countries around the world. Parker has increased its annual dividends paid to shareholders for 52 consecutive years, among the top five longest-running dividend-increase records in the S&P 500 index. For more information, visit the company's web site at http://www.parker.com, or its investor information site at http://www.phstock.com.
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