Richard Hobbs (left) and Ian Taylor (right) of Stoneridge Pollak

Wittmann UK’s nine nest cell for Linpac Dunstable featuring Kawasaki robot

November 4, 2002

Wittmann UK is seeing increased demand for 6 axis product handling systems from its leading

customers: Solutions typically involve Wittmann 3 axis robots for beside-the-press applications and the integration of Toshiba and Kawasaki 6 axis robots for downstream operations.

The automotive sector is leading the way through cell-based systems and customers such as Linpac, McKechnie, and Stoneridge Pollock. Packaging and telectronics manufacture are also large users and Wittmann UK sees growing interest from medical plastics and also in non-plastics sectors such as metals fabrications and forgings.

Most cell-based solutions build around the Wittmann CNC controlled linear robots which remove the mouldings from the tool. The Toshiba 6 axis robot is then usually deployed for assembly, insert moulding work, inspecting, measuring and packing and using feeders, conveyors and cameras as required. The Kawasaki range of 6 robots is also used for operations such as further inspection with fitted vision systems, end of line palletising and packaging operations.

Speed of operation and cycle-time is often the rationale for the Wittmann and Toshiba manufacturing combination: Wittmann UK’s fastest cycle-time project supplied to date is a £200,000 demoulding and packaging cell that produces and packages two mouldings every 6 seconds.

This cell – supplied to a packaging industry moulder - features a Wittmann servo robot, a Toshiba six axis robot, a nesting system and conveyor: The Wittmann robot takes two moulded components from the moulding press and presents them to a nearby 2 x 2 component nest table. The Toshiba robot then picks up the parts and positions them in correct alignment within six cavities of a specially designed pallet resting on an adjacent conveyor. The Toshiba robot is fitted with an extra long stock of 400mm depth in order to achieve the rate of fill needed.

The crate’s capacity of 270 packaging lids is filled by the Toshiba every 13 minutes. When this pallet is full, it is then automatically released to the end of the conveying line. The operator is then merely required to bag the completed box in a polyethylene sack ready for despatch. The next empty crate is automatically presented, ready for loading.

The Wittmann + Toshiba configurations are particularly popular for insert moulding work in the automotive sector with McKechnie, Stoneridge Pollock and Linpac Automotive all recently commissioning new systems.

Unit cost savings and cycle time improvements of 30% have been achieved, for example, at leading automotive moulder and electric switch manufacturer Stoneridge Pollak Ltd on a vertical-press Toshiba robot supplied by automation company Wittmann UK. Stoneridge Pollak has just finished installation of its second Wittmann + Toshiba system. (The company also runs two Wittmann based cells).

The cell moulds a two-piece insert part – a window lift switch, with metal electrical connectors set in glass filled nylon – that is supplied to the VW-Audi group for use in Golf and Skoda cars at a rate of about 7,000 components daily. Total SPL investment in the new cell - which includes two Toshiba SR 654HSP robots and a Battenfeld rotary injection vertical press, together with vision systems and bowl feeders also supplied by Wittmann - amounts to some £250,000.

Previously, the component was very labour intensive, occupying a two-man team on a three-shift pattern for 24 hours a day. Automation not only made manufacture more consistent over the whole manufacturing run, it also highlighted inconsistencies and deviations within the metal insert supply, rectification of which improved overall product quality and consistency.

Linpac Automotive has also been using Wittmann supplied technology to gain a competitive edge. Linpac Dunstable, for example, has been using Wittmann + Kawasaki technology in handling the production of Rover 25 rear spoilers.

The production solution at Dunstable is an automated nine tool cell, at the heart of which is a Kawasaki 5-axis robot. It picks and places the two mould parts, fascias and inserts, into a series of nine mould tools, or gluing nests which are stacked in vertical groups of three on three sides of the robot.

The cell was first assembled and fully proven at Wittmann UK’s Wellingborough headquarters before transported to its installation at Linpac Dunstable.

Previously, the two parts of the R25 rear spoiler had been vibration welded together. The automated gluing alternative was pursued for three main reasons; to improve quality; to reduce handling operations and to improve net productivity on the part-production.

The fascias and inserts are both moulded in a PC/ASA polymer blend on a nearby Negri Bossi 1000 tonne locking force moulding machine fitted with a Wittmann removal robot and bespoke Linpac de-gating system. Once trimmed and de-gated, both the inserts and the facing parts are then supplied to the new automated gluing cell via a hole-in-the-wall conveyor system.

The Kawasaki robot is fitted with vacuum grippers of 10kg holding force and it firstly lifts and inspects the exterior facing side of the part by holding it up and presenting all its aspects to a fixed camera positioned above. If satisfactory, the robot then places the part into one of nine nests or glue moulds, which were specially commissioned and tooled by Wittmann UK from a local toolmaker using Linpac and Rover CAD data.

As the robot returns to pick up the second half of the moulding (the insert), specially fitted clamps on the open tool automatically adjust the fascia half of the part to the bottom half of the tool, fixing it to receive the insert.

The insert is then given the same vision inspection for defects as the outer fascia. If this is satisfactory a fixed glue dispenser, supplied by Wittmann partner Liquid Controls, begins its operations. The robot moves the insert under the stationary nozzle to a predefined pattern of glue application. It takes about 8 minutes for the nest to do its work in sealing the two mouldings together, by which time the robot has filled the other 8 nests, and is ready to take the finished spoiler out of the first cell before filling it with another pair of parts.

The Kawasaki robot’s capabilities have not been overlooked by adjacent manufacturing sectors such as metal fabricators. A hint of the possibilities for extruded fabrications is given in the work done by Wittmann UK for Ashford-based SICO.

Wittmann UK designed and installed a production cell that automates the punching and cropping operations of SICO’s production of steel leg furniture components for the educational, hotel and public space markets. In this instance the technology is metal-based but the company is confident of showcasing it to appeal to plastics operations.

SICO’s automation cell features a Kawasaki 6 axis robot, a feeder system for the steel leg tubing and an array of custom-built grippers and off-loading equipment, designed and built together by Wittmann UK on site in consultation with the client.

At the outset Wittmann UK showed SICO production staff the automation facilities it has designed and installed at Unipart and at Linpac Mouldings in Dunstable. Training in the robotics and Kawasaki programming was delivered to SICO operatives at Wittmann UK’s Wellingborough factory over a two day period prior to full commissioning in Ashford.

Typical cycle times for turning, crimping and finishing each leg length range from 15 to 45 seconds. A full batch run may take some three hours to process. SICO operates a two shift daily system at the Ashford works and the new Kawasaki robot is being deployed some 22 hours out of 24.

Barry Hill, Wittmann UK managing director notes that ‘assembly line work and product handling tasks are now a key part of our work as suppliers of automated systems. This is a part of the industry that is set to grow - well into the foreseeable future.’

Wittmann is one of the world’s leading producers of robots, automation, ancillary and mould heating and chilling equipment for plastics and other manufacturing industries, with production plants in the USA as well as Austria, Hungary and the UK. The Wittmann Group currently employs 580 employees and enjoys a revenue of some 120 million euros.

Further details from Wittmann UK. Tel. 01933 275 777