Automated production machinery designers and manufacturers are increasingly specifying polyurethane and rubber belts with specialised backing materials and custom machined features to provide higher throughput solutions for parts and materials handing and to solve complex processing functions. Transdev, the Poole based power transmission specialist and manufacturer is geared to provide innovative solutions with an expertise that extends to an unmatched range of adhesive bonded and vulcanised materials to aid parts transfer, increase wear resistance, reduce and increase friction and improve in-process durability. In addition, extensive precision grinding and machining facilities are available to produce both synchronous and friction drive belts with flights, pockets, slots and holes for belt lengths up to 70 metres and widths to 600 mm.
Most applications are suited to an adhesive based bonding technique where belt backing materials are characterised by flexibility, friction, durability and resistance to process conditions. Backing materials include natural and nitrile rubbers, PVC, microcellular and cellular polyurethanes, polyester, silicone, nylon and leather. Many application specific, customer-specified materials are also used in the process. For some materials the backing process inherently decreases the bending ability and machining stress relief slots across the belt ensures up to 30% increased flexibility. Combination layers of different materials can improve deformability for delicate parts handling while retaining high friction surfaces with wear and abrasion resistance.
Bonded material friction requirements can include either low or high coefficient characteristics for grip or slip parts-handling. In some cases materials such as silicones allow excellent grip with a clean breakaway for labelling and adhesive material dispensing. Moulded features such as herringbone patterns or a dimpled finish can be applied to improve or otherwise influence material handing characteristics. The wide range of materials available provides the best combination of performance features and resistance to aggressive compounds including acids, oils, fats and salts typically used in food, pharmaceutical and chemical processing industries. Belt backings can be also be specified to improve external belt wear resistance, to meet anti-static requirements, to colour code a process area and many materials are available to comply with FDA, BGA, JFS and other standards approvals.
Adhesive bonded backings are very durable but they are mainly restricted to single direction usage as they employ a natural seam that runs across the width of the belt which may delaminate on intensive reversal conditions. Where bi-directional use is a necessity, such as haul-off belts, puller belts, forming and nesting belts, Transdev have invested in high pressure vacuum autoclave equipment and developed a process to vulcanise materials under vacuum; producing a seam-free layer of backing material with a superior adhesive-free bond to the belt material that has no tendency to delaminate. A wide range of belt and backing materials suited to this process are available.
Precision ground or machined, back, face and edge finishing includes slots, holes, grooves or parts handing features such as pockets and cleats. Lengthways and sectional profiling can be used to stress relieve backing material - especially where small diameter pulleys are used. Tooth removal from timing belts can provide clearance for mechanically attached profiles or to produce vacuum grooves where the backing surface may also include a low friction coefficient material. It is also possible to combine belt backings with machined fixtures fitted with threaded inserts to provide specific parts handling features or flights for synchronised processing.