Originally Published EMDM November 2005
INDUSTRY NEWS
Compact Pneumatic Components Are Linchpins of Automated Contact Lens Manufacturing System
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| Pneumatic grippers are among more than 400 Festo parts used by system integrators Barr & Paatz in the construction of a fully automated contact lens manufacturing machine. |
A fully automated contact lens manufacturing machine integrates injection moulding, plastic dosing, curing, hydration, packaging, and autoclaving into a system that has an 8-m2 footprint. Designed by system integrator Barr & Paatz (Totnes, Devon, UK) for Clearlab (Plymouth, UK), the unit relies on more than 400 pneumatic actuators supplied by Festo Ltd. (Fleet, Hants, UK).
The actuators are used throughout the machine, organized into cells for each process stage. Each cell consists of one or two valve terminals and operates semiautonomously as an I/O extension to the control system inside a Bosch Rexroth articulated robot. Nine robots perform pick-and-place operations.
Barr & Paatz chose to base the pneumatics design exclusively on Festo products largely because of the added value that such an approach brought to the project. The common physical and interface standards that come with parts from a single supplier simplify construction of the handling axes, integration of accessories, and general system building, says the firm.
A further advantage noted by the company is the ability to choose optimized component designs. Festo’s compactly designed cylinders, for example, are approximately 40% shorter than industry-standard parts. The firm also cites the use of VADM modules, which combine a vacuum pickup function with a blow-off ejection mechanism. These parts save space in the front-end lens handling area and reduce air consumption through close coupling and electronic controls.
The sheer size of the pneumatics system made the choice of a valve terminal critical. Barr & Paatz selected 10-mm-wide modular MPA valves with a high flow capability. The valves are mounted on Festo’s high-density CPX valve terminal backplanes. The MPA portion accommodates up to 32 single- or dual-port valves fitted with a Profibus interface for system integration. More than a dozen of these backplanes are distributed around the machine. In addition to controlling the pneumatics, the backplanes provide digital I/O expansion for the robot controllers.
The surface features of the Festo components and the common interface system provide a “tidy way to build a large automation system,” says Stirling Paatz of Barr & Paatz. “This has saved a considerable amount of space, which in turn allows our client to increase manufacturing capacity within a very small footprint.”
Believed to be the first fully automated contact lens manufacturing machine, the system can produce more than 24 million lenses per year.
For more information about Festo’s products, contact the company at Technology House, 1 Fleetwood Park, Barley Way, Fleet, Hampshire GU51 2QX, UK; phone: +44 1252 775000; fax: +44 1252 775001; Internet: www.festo.com. To learn more about its systems integration capabilities, contact Barr & Paatz, 7-11 Paragon Units, Ford Rd., Totnes Ind. Est., Totnes, Devon TQ9 5LQ, UK; phone: +44 1803 866607; Internet: www.barr-paatz.co.uk.
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