Challenging times

The Korber Schleifring Group mounts a grinding symposium once every three years at its Studer, Thun, Switzerland site. Machinery was there to hear both business and technology news
At the Schleifring Group Symposium in May, held once every three years at Studer's Thun, Switzerland location, the German grinding machine specialist outlined its business and technology position. In fact, of the parent Korber Group's total turnover of €1.75 billion, only 28 per cent is accounted for by machine tool sales, via Korber Schleifring. Korber Group's other activities include tobacco and paper machinery, plus pharmaceutical packaging systems.
But the 2008 financial year was a good one for the Schleifring Group's grinding machine activities, with turnover reaching a record high of €486 million – revenue has grown from €267 million in 1999. Of the sectors served, automotive is still far and away the largest segment of its business, claiming some
€136.2 million of total machine tool sales; behind tool and cutter grinding, €97.7 million; general engineering, €74.2 million; and then turbines, €66.3 million. Of the latter sector, Schleifring managing director Dr Ralf Kammermeier said that the group is the market leader. But he did not shirk from acknowledging that there is a "crisis" in the machine tool industry and admitted that the Schleifring Group is being affected.

As at June last year, orders were up
10 per cent he offered, but the out-turn for 2008 was 10-15 per cent fewer orders: "nobody could have expected this," he said, with this leading to an order intake of €440 million versus 2007's €510 million. And he referred to the UK's Oxford Economic Forecasting's grinding machine global outlook by way of further demonstration. In 2008, the market was worth €3,077 million: it is projected to fall to €2,111 million this year; €1,890 million in 2010; and then rebound to €2,310 in 2011.

The automotive market for grinding machines is expected to drop since world unit car volumes are predicted to fall from 2007's 65 million to a low of 51-57 million in 2009, before heading back up to 61 million units in 2010. The aircraft industry will also see a reduction in passenger aircraft production before rebounding in 2012, it was further added. The predicted out-turn is for a 21 per cent fall in value and 35 per cent drop in volume before growth returns in 2013.
FARING BETTER
But Schleifring was, he offered, faring better than the German machine tool industry as a whole. While the German machine tool builders' association, VDW, highlighted an order drop-off of 70 per cent in Q1 year-on-year, Schleifring had performed better with just a 35 per cent drop – "we can deal with this,"
Dr Kammermeir added, but said that the company would have to get used to a demand that is 30-40 per cent lower during the next few years.

In responding to the challenge, the group's production site concept will see it make better use of synergies; be more flexible; support standard processes; build on core competencies; use capacity more efficiently; gain cost benefits of shared platform design; develop a sourcing strategy – concentrate on its core competencies and outsource other parts; and it will make locally for local markets. Some €25 million will be invested in realising this strategy during the next few years, it was revealed.

Production activities will be concentrated in three sites – Thun, Switzerland; Walter Kurin, Czech Republic; and Shanghai, China. Assembly and customisation of machines will take place within the other group sites, such as those at Hamburg (Blohm) and Göppingen (Jung), Germany, plus the recently acquired Combitec internal grinding company, in Switzerland.

Moving on to technology, the managing director outlined some current developments in brief. He underlined the shared platform technology between Studer and Schaudt, as regards the S22, CamGrind S and ShaftGrind S machines, and also added that the two are working to develop a new external grinding module, from which they can configure task-specific solutions for gear shafts and camshafts. There is also to be greater co-ordination between Blohm and Jung regarding machine and control system development, with an innovative machine project underway that will see new Jung machines developed for the medium technology segment – "something that we have never managed before" – during the next two to three years. This will result in three different size machines with three different controls. For Blohm itself, there won't be so much change, it was added. Studer and Mikrosa will work together on inspection technologies, while a highly precise flat grinding machine will be be made at Thun. In the case of Walter and Ewag, there will be further "consolidation", the machines from these two companies already sharing many common components.

Specific developments highlighted at the symposium took in: a Blohm Jung diamond dressing development, GEOID; the new Ewag Compact Line tool grinder; transmission shaft machining at
200 m/sec on a Schaudt ShaftGrind S; Combitec CT-450L, CT-960 and S120 machines; plus ToolStudio software developments.
DRESSED TO IMPRESS
In more detail, Jung has always been associated with pioneering grinding developments, it was highlighted, with its PA37K continuous diamond dressing device offering 50 per cent cuts in production process times, while setting up the dressers is also fast. For its six-diamond, star dresser, it claims "six minutes for six diamonds", while for a diamond disc it is 10 minutes. This sort of performance is enough to justify Jung technology, it was asserted, but now another major step had been taken to further improve this technology. GEOID takes into consideration the fact diamonds are not round, so, as the contact angle between a diamond and wheel changes, error is introduced. But apart from computing a more accurate path – ±0.005 micron accuracy is now ±0.0025 micron. Benefits also include double the use per diamond (halving tool cost), plus reduced setting times.

The Ewag Compact Line, launched at EMO 2007, was shown in its new PCD/CBN module guise, with an integrated Fanuc robot for loading/unloading of inserts. The Compact Line is intended for the production of smaller batches of inserts – 10s or 100s, not 1,000s. Therefore, short set-up time is the key factor. With a potential for six different types of workholding, set-up time is just 10 mins, and it can be set easily to work with or without robot loading.

Schaudt's ShaftGrind demonstrated high speed peel grinding at up to
200 m/sec, by means of a reduced weight grinding wheel made from carbon fibre, not steel: so 3 kg versus 25 kg. In theory, grinding at wheel speeds up to
300 m/sec is possible, with plunge feedrates of up to 15 m/min and axial rates of 30 m/min operating. Applications highlighted were gearshafts and turbo shafts, with camshafts already a success with customers in Europe and Asia – two cam lobes with different timing could be ground simultaneously, it was further explained.

The acquisition of Swiss internal grinding specialist Combitec, late last year, offered the Schleifring Group the possibility of introducing a new line of grinding machine tools at this year's gathering and it highlighted three units.

The CT-450L – an entry-level model – is an internal and universal cylindrical grinder for new users and is, in fact, the 'light' version of the bestseller CT-450. With a wide range of applications, the CT-450L is equally suited to universal internal grinding applications, grinding collet chucks and machining brittle hard materials. Special features are the linear spindle arrangement, use of either one or two belt spindles (having speeds of between 28,000 and 60,000 rpm), and cross-slide design. The CT-450 provides a range of expansion options, such as a C-axis for grinding all types of threads.

The CT-960 – a high-end universal machine – is an internal, universal and radius grinder, with a B-axis swivel to 91°. A turret for up to four spindles permits efficient grinding of small to medium-sized workpieces. The optimum stability and rigidity of the CT-960 permits grinding die with radii, cones or path contours. The finished workpieces have polished surface quality. An optional CNC-controlled C-axis is available for grinding threads or non-circular shapes. Sim-CT software helps with programming, set-up and simulation.

S120 – a speedy production machine – is an internal cylindrical grinding machine for one or two independent grinding tasks. Optimally suited for efficient machining of high-precision small parts, it is well established in large batch production. Typical applications are in the area of hydraulic components and, increasingly, in medical technology; for example, grinding ceramic balls for hip joints. Different handling systems can be integrated via the loading interface.

Walter ToolStudio developments centred on increased capability, as regards the development and manufacture of complex tools without specialist knowledge, via Wizards and a knowledge database. But while Wizards generate the tools, the user can always edit the underlying system-derived values. Graphic 3D simulations allow for the capture and correction of errors on-the-fly, while there is also virtual probing, particularly useful on small tools, where actual physical probing is not possible. And, importantly, a machine will not start if a collision is detected by the software, even if the operator has ignored it.