Staubli Connectors
A key element in the operation of an efficient injection moulding shop is the ease and speed of changing moulds; mould transfer tables often provide the single most cost effective productivity improvement and are a key element in achieving Single Minute Exchange of Dies (SMED). Here, the technical experts at Stäubli’s Connectors Division explain more about the advantages of mould transfer systems.
Maximising flexibility and productivity on injection moulding machines is essential in a competitive environment; minimising downtime on mould changeover provides one of the best opportunities to improve performance and profitability. Mould transfer systems can be manufactured for applications ranging from lightweight moulds producing small electrical components through to large heavy moulds typically used for car bumpers or dashboards. Significant reductions in changeover times have been achieved using transfer systems, in some applications reduced by over 70 percent, even where quick mould change systems have already been installed.
Transfer tables provide economical and safe side-changing of moulds, especially where the workshop layout precludes the use of cranes or where access to craneage is difficult. They can be moved into place simply using a fork lift, eliminating any wait for the use of cranes and handling equipment. The mould is held securely on the table reducing the chance of damage to the mould or its connectors and operator safety is improved. Adapted to the specific needs of each application, incorporating manual push/pull systems for smaller moulds or powered transfer units for larger moulds, transfer tables offer one of the most simple, achievable and cost effective improvements to the operation of the moulding shop, giving rapid payback on investment.
For more automated systems a cost effective layout is positioning one transfer system between two machines; the two-directional loading table serving both machines and providing maximum flexibility and efficiency for each production cell, incorporating if required a preheating station. Where automatic mould changing is required then positioning a transfer system on each side of a machine is ideal and provides the fastest method of mould changing. On one side, the mould from the previous production run is unloaded, while simultaneously on the opposite side the new mould is loaded.
A further step towards complete automation, that is often included in new installations, is the use of rail carts; a rail mounted loading/unloading table transfers moulds from the storage area direct to the moulding machine.
Rail carts can service several or even an entire line of machines. More versatile are moveable carts permitting free movement of moulds between several machines and storage areas. Adjustable height mechanisms built into the cart ensures adaptability to different machines or storage areas while mould-locking devices on the cart ensures safe and secure transfer.
Maintenance and repair of moulds also needs to be fast and efficient to avoid production delays. Maintenance stations can be fitted with turnover mechanisms that provide a convenient and secure platform, holding the mould in the correct position for the work required.