2003-09-05 - A technology partnership between Kettering based Hi-Tech Automation and ABB has led to the development of two state-of-the-art automated manufacturing cells for the Stamford Bridge, East Yorkshire operation of McKechnie Plastic Components. The two cells, commissioned in April this year, manufacture flagship products for Scholl Foot Care, a division of SSL International PLC.
McKechnie Plastic Components, with a long history of investing in automation technology, was invited by SSL to bid for the design, development and manufacture of the products, two new types of foot file, last year.
For the bid to be successful, McKechnie had to consider two crucial elements. First, it had to provide an effective design that would eliminate risk of the product’s metal foil insert being displaced during continued use (with risk of injury to the user), and then to consider how it could manufacture the product at an extremely competitive unit price.
The first element was achieved by McKechnie developing a breakthough process whereby the periphery of the metal insert is encapsulated during injection moulding. Though this proved successful, the process required considerable development by McKechnie due to problems encountered with trying to locate and fix a metal insert within molten plastic.
To fulfil the second element, McKechnie needed to consider implementing a new automated manufacturing procedure, which, within tight budgetary acquisition constraints, was capable of ramping up efficiency by slashing manual labour costs and reducing waste, while also handling product throughput in a totally hygienic manner. Such a system would also accrue other benefits, primarily in the elimination of the risk of repetitive strain injury to operatives.
Having worked successfully with ABB before, particularly with surface finishing robots, McKechnie’s Automation Manager Allen Clovis initially approached ABB Senior Account Manager Colin Jakes about the project and how the necessary automation could be implemented. ABB has a wealth of expertise in the field having already supplied some 15,000 robots to the plastics industry.
Jakes then enlisted the expertise of one of ABB’s preferred partners in the plastics industry, integrator Hi-Tech Automation and its co-founder Gary Probert. The team had already worked together before on another highly successful project for McKechnie, developing an automated cell for the transfer and packaging of plastic cases for razor blade cartridges. This project was probably one of the first in allying a Sytrama beam robot with an ABB six-axis robot on the same application.
For the new Scholl product cells, Gary Probert and his team at Hi-Tech Automation, working very closely with the McKechnie and ABB people, devised a fully automated solution that eventually met all customer requirements and eliminated the need for human intervention at any stage of the product cycle.
Probert comments: ‘The new process threw up considerable mechanical design and positioning problems for us, though through intense development work by our engineers, backed up by close liaison with both McKechnie’s automation department and ABB, effective solutions have been found.’
The two cells, adjacent to one another at the East Yorkshire plant, are each dedicated to a single product. One cell manufactures products incorporating an abrasive coated pad, while the other cell manufactures a similar product incorporating the metal foil insert already discussed.
Hi-Tech opted for the proven configuration already used on the razor blade case application, integrating a Sytrama beam robot for carrying out loading/unloading requirements for the injection moulding operation and an ABB IRB1400, six-axis robot for downstream distribution of the product.
Since the foundation of Hi-Tech Automation in 1996, Gary Probert has incorporated countless beam robots into his customers’ production lines but is increasingly looking towards six-axis robots as a solution to flexibility requirements in the production of high-volume products. Six-axis robots are ideal for complex injection moulding jobs where cycle times have been reduced and post-moulding processes need to be performed rapidly - a task particularly suited to a fast and flexible robot. Six-axis robots can be quickly adapted for different applications and product design variants and can be used for a range of tasks from insert loading through to assembly and packaging.
As well as the beam robot, six-axis robot and injection moulding machinery, each cell also incorporates a bulk feed point for the inserts, robot-to-robot transfer station, ultrasonic welding equipment and an out-feed conveyor.
The product cycle devised by Hi-Tech Automation is simple yet extremely effective. In the metal insert product cell, for example, magnets attached to the beam robot arm pick-up eight metal inserts (four fine/four coarse) fed from two bulk-feeding systems and the robot transfers and positions the inserts within the injection moulding machine. The product is moulded around the insert and the beam robot then removes four top and four bottom product halves (complete now with foil inserts) and transfers them to the transfer station. The halves are arranged face down, in two rows of four, with the product tangs adjacent to one another. One row is then rotated through 180 degrees by an electro-mechanical positioner and placed on top of the other row, at which point a cylinder housed overhead the transfer station presses the two halves together to form a single unit. The ABB robot, equipped with special tooling, then picks up the four now complete products by their tangs and transfers them to the welding station, where they are ultrasonically welded, one-by-one, using an indexing system. The ABB robot waits on ’standby’ until ultrasonic welding is complete, at which point it transfers the product to a tray on the out feed conveyor. By this time the beam robot is already into its next cycle. The ’coated pad insert’ product cell is similar but with minor variations.
Even though each cell is currently undergoing two to three months ’bedding-in’ and ‘work-up’ before expecting to achieve optimum cycle time, system malfunctions are now minimal.
Summing up the project so far, Allen Clovis comments: ‘We can’t throw manpower at a product in the same way as the Far East - to compete we have to provide a superior product design and then automate, however complex or difficult that might be. To this end, the Scholl project has been a real team effort in overcoming these difficulties. The innovative product design and pro-automation culture within McKechnie was a driving force, though this has been ably complemented by the ‘can-do’ efforts of Hi-Tech Automation and its technology partner ABB. All participants have worked long and hard to bring a particularly technically demanding application to a successful conclusion.’