As part of the latest initiatives, activities in Redditch have expanded into assembly of 5-axis machines for world markets in addition to 4-axis models. The site is also a global competence centre for turnkey projects and innovative manufacturing solutions.
Says David Evans, operations manager at the plant: “As part of our expansion, we recently installed an 11-station Strothmann flow-line and new logistics system for complete manufacture of horizontal machining centres. Originally, our machine assembly was purely a mechanical process on an adjacent flow-line and the machine had to be lifted off to be finished in a separate part of the factory.
“When we first moved from block assembly of machines in one location to the old flow-line, there was an immediate 20% increase in productivity. The new Strothmann system has resulted in a further reduction of at least 20% in overall assembly time and we intend to improve on that further by making the process even leaner.”
Mechanical assembly of horizontal machining centres is completed over the first four stations in the line. All bed assembly is carried out off-line and the casting is delivered to the first carriage with the linear guideways already fitted. A majority of the pre-assembled groups of components are added at this first station, including the machine column, pallet changer and the energy unit powering the hydraulics and pneumatics.
The Strothmann carriage is raised pneumatically and pushed along rails set in the floor to the next station location, where the air pressure is released and the carriage lowered to the floor, a process that takes about two minutes. The main part of the work here is to attach the electrical cabinet, which is craned across from another part of the factory. Some of the ancillary equipment, including cables and pipework, is also fitted.
At the third station, two further major groups are added, namely the tool magazine and changer assembly and the machine guarding. Station four, which completes the mechanical assembly phase, sees all of the pipework and cabling routed from where it originates to where it needs to be connected.
Electrical commissioning can take two, three or even four days, depending on software, customisation and everything else that needs to be completed, so occupies the next one or two stations. Later stations in the line are deployed similarly flexibly, according to the amount of work required. This includes geometrical alignment, laser calibration of the axes and an alignment test.
The last part of the process is to machine a standard NAS (National Aerospace Standard) test piece, which is inspected by an independent team of metrology staff to give a guarantee of the machine’s accuracy.
Once each horizontal machining centre reaches the end of the line and is removed for despatch, the Strothmann carriage is lifted by crane and carried back down the gangway to the start of the line to begin the process again.
Heller’s managing director in the UK, Dipl.-Ing. Matthias Meyer concludes: “The fact that we manufacture in this market gives our customers in the UK and Ireland considerable added value. Not only do our staff have a level of product knowledge that is much deeper than it would be otherwise, but also we can call on shopfloor operatives, all of whom are apprentice-trained, to help out with installation, commissioning and service, if required.
“Another benefit is that customers are welcome to visit us and see their machining centre actually being built, if it happens to be a model that we produce. Whatever machine they are buying, they can see the quality of engineering input, which is standard across all of our factories.”
