The Worcester brand, owned by Bosch as part of its Thermotechnology division since 1992, has become synonymous with quality and has recently being awarded 23 Which magazine ‘Best Buy’ accreditations for its Greenstar gas-fired boilers.
In fact, the Greenstar energy-efficient condensing boilers are some of the most successful ever manufactured, with more than 1.5 million sold in the UK. Even more impressive is Worcester’s commitment to quality; as part of the manufacturing process, each boiler goes through up to 10 quality-control checks, and the company’s failure rate for boilers in the field is widely regarded as the best in the industry.
Worcester’s headquarters and manufacturing site (in Worcester) has traditionally been focused on the final assembly of boiler components manufactured by its supply chain, but this is beginning to change. Manufacturing engineer Murugadoss Panneerselvam says: “We are predominantly an assembly-oriented plant, but Bosch Thermotechnology has taken the strategic decision to embrace more core manufacturing activities, and this includes the use of production machining. The initial focus of this move has been the development and manufacture of a next-generation heat exchanger, which will be rolled out across the Bosch Thermotechnology range of boilers.”
Aluminium fabrication
The current heat exchanger used in the Greenstar series is a sand-cast model made of a composite of aluminium and stainless steel. The new heat exchanger is an all-aluminium design, which is more compact and capable of delivering a higher output than the existing model.
The manufacturing process for the new heat exchanger uses ‘state of the art’ welding technology to create the component, which is then machined prior to final assembly.
Mr Panneerselvam says the decision to increasingly bring core competencies in-house meant that Bosch Thermotechnology’s engineers would need expert advice and support.
“We knew that machining would require us to improve our expertise and acquire know-how that we did not possess.”
Production engineer Chris Packer says: “For this reason, it was important that our machine tool supplier didn’t just deliver a machine. We needed a company that would stand behind us and steer us in the right direction, in order to facilitate the successful introduction of the product and achieve project targets.”
Bosch Thermotechnology surveyed the entire machine tool market, basing its decision on a set of criteria that included service, cost, quality, technical solution, after-sales support, lead time and financial stability of the supplier. The company subsequently chose Yamazaki Mazak UK Ltd (www.mazak.eu) as its partner and ordered four new Mazak HCN 4000-II three-axis horizontal machining centres.
These machines are equipped with a high-speed milling spindle capable of 18,000rev/min, fast feed rates for optimum production efficiency (rapids are 60m/min), and easy programming via the Mazatrol Matrix conversational programming system.
Keeping promises
Mr Packer says: “One of the key issues for us was lead time, as the machines were being shipped in from Japan. We were promised de-livery dates for the new machines, and those promises were kept — one of the vital factors for any project’s success.”
Mr Panneerselvam adds: “Equally important was the support offered once the new machines had arrived. The critical issue from our point of view was that we had to optimise the manufacturing process from the very beginning. We had no capacity to get things up and running and then optimise; we needed full production efficiency from the outset.
“As a result, our engineers leant heavily on their Mazak counterparts, who have been very responsive to our needs, including helping us to optimise the cutters to ensure that we reduce cycle times and minimise the cost of consumables during the process. The service and support has been exemplary, particularly in terms of training; once our technicians were trained on the Mazatrol control, they found it very easy to use.”
In conclusion, Mr Packer says: “Mazak did not simply sell us machines, they sold us a turn-key solution that was ready to use and fitted easily into our current production processes, thereby enabling us to ensure business continuity and a clear return on our investment targets. Within Bosch Thermotechnology, this move into more core manufacturing has been very high-profile and is being monitored closely by senior management. With these sorts of pressures involved, it was critical that our machine tool supplier worked closely with us.”