MACH 04

The international exhibition of machine tools and manufacturing technology, MACH 2004 – at the NEC from 19-23 April, includes more than 400 exhibitors from the UK and overseas.

The international exhibition of machine tools and manufacturing technology, MACH 2004 – at the NEC from 19-23 April, includes more than 400 exhibitors from the UK and overseas and will encompass the whole spectrum of metal cutting and metal forming machine tools equipment.

The latest trends in the sector, such as one-hit machining, automation and the use of software, will be covered in a series of free seminars during the five-day event.

Some of the basic issues and techniques of five-axis machining will be examined on day one, while day two will be devoted to developments in automation technology and the best approach to increasing productivity. Dr Ken Young, director of the British Automation and Robot Association, will also look at the common pitfalls of automation projects.

Other discussions throughout the five days will cover topics such as advances in materials and metrology, the latest developments in EDM and cutting tools, metal forming and nanotechnology.

The trend towards one-hit machining, automation and the increased use of software is the result of a greater appreciation of the benefits of new technology among even small companies.

In particular, the drive towards the elimination of waste as part of the ‘lean’ approach to manufacturing, has encouraged machine tool firms to take advantage of technological advances to meet their customers’ needs.

One-hit or ‘multi-axis’ machining has emerged as the most dominant theme within product portfolios of machine tool builders. Compared with multiple set-ups, the obvious benefits include time saved, and removing the possibility of incorrect alignment. Perhaps the clearest manifestation of this trend is that five-axis (usually horizontal) machining centres have emerged as a highly successful species within the machine tool genus.

According to Paul Maynard, president of the Manufacturing Technologies Association, the focus today is to fully integrate and combine as many operations as possible into a single machining cycle on a CNC machine tool.

‘It’s all about productivity – reducing delivery lead times, and responding to customers and design changes,’ said Maynard. ‘A further factor in the equation is the demand for improved tolerances and higher consistency of production. By using computer technology to combine different features of a component into single-cycle geometric relationships of the different elements – such as drilled holes and milled slots – can easily be maintained. Previously they were all subject to different operations on different machine tools which involved numerous jigs and fixture relocations,’ he said.

Meanwhile robots and automation systems are increasingly being designed into new production systems or factory layouts and they bring a two-fold benefit; greater productivity, and the transfer of back-breaking work from humans to machines.

According to GKN Driveline, the installation of automatically loaded machine tools has boosted vehicle component production by half. Over the past few years the company has replaced pairs of external, angle-approach grinders with single hard-turning lathes for machining critical features on an extruded steel component known as a ‘bell’, the outer race in the constant velocity joint. The latest hard-turning lathe to be installed has a robot loader and forms part of a largely automated cell for bells production.

Compared with two similar cells that comprise all manually-loaded machines and produce 450 components per shift, the automated facility produces 700 in the same time, said Paul Daniels, the engineer responsible for the cell at GKN’s Birmingham plant. A further advantage for GKN is that automation means manning, an expensive part of production, can be reduced. whereas five operators are needed to run a manual cell, only three are required for an automated one.

Others who have experimented with automated production claim big labour savings and productivity increases of 30-40 per cent, due in part to running the machines unmanned for two hours between the day and night shifts.

Colchester Lathe, has also pursued the automation strategy, but has produced a ‘Lights Out’ machine package. The unmanned turning cell has all the functions totally integrated into its design complete with feedback correction, onboard CAM programming and work scheduling software.

Speed and efficiency are not the only reasons manufacturers are increasingly looking to automation. Alastair Johnson of Designplan Lighting of Sutton, Surrey, said: ‘Unemployment here is very low and is not an area where sheet metalworking skills are traditionally found, so it is difficult to recruit good staff. We were therefore keen to start automating these functions as part of an ongoing production improvement and cost reduction programme’.

Multiaxis machining and automation would not be where it is today without developments in the processing power of controllers, and in CAM software, which help unlock the potential of the machine (see CPC feature, page 63). Ten years ago at machine tool fairs, software houses were the sophisticated but unexpected guests. Now they walk alongside the ‘hard’ technology, acting as a stimulus and a partner.

Software and controls have also been important to the proliferation of ‘high-speed machining’, where fast processing is needed to keep pace with machine capability. This branch of technology has transformed the way high integrity parts for aircraft are produced, as well as a huge range of consumer products, such as mobile phones, mainly via plastic moulds for injection.

One other important development over the past few years, is the improvement of drive systems. The servo motor has allowed hydraulics and pneumatics to be eliminated in machine design which simplifies maintenance, enables a more compact machine to be designed and has become important for the use and development of control systems and software.

Consequently, cycle times are being halved and idle times awaiting machining systems to communicate and confirm movements have been cut.

These trends are important for yet another reason. In the global marketplace, UK manufacturers are under threat from low-wage economies, such as China, India and the former Eastern bloc countries who can charge up to 30 times less than UK operators. The result is that many have moved production abroad in recent years or sought other ways to lower production costs.

But according to industry representatives there is a silver lining to this cloud. Once UK companies start to move to one-hit machinery, overseas sub-contractors have less of an advantage. Sending parts to the UK in batches keeps transport costs down, but can causeproblems for customers who want the equipment assembled as quickly as possible. Also, UK sub-contractors have the ability to supply components and sub-assemblies just in time to UK manufacturers, directly to the production line if required.

Treworrick Engineering, installed two automated turning cells – a bar-fed lathe and gantry loaded model – and is now able to compete for contracts that may have been lost to overseas sub-contractors, according to director Richard Avery: ‘We have a longstanding customer in the hi-fi business that went straight to an Asian sub-contractor for large volumes of a new component. however, due to a quality problem with the imported parts, the company asked us to tide them over by running off 4,000 and to their surprise, our quote on this quantity based on using the bar lathe was within one per cent of the price they were paying in Asia for the larger volumes.’