Multi-Purpose Machines Ensure Enhanced Independence

The crisis is over, but selling machinery remains a tough business. Machine tools nowadays have to be veritable “jack of all trades”, able to handle all kinds of materials, to manage without any process materials as far as possible, and be capable of adapting to new job profiles with maximised flexibility. Two highly respected experts on machining and forming from Dortmund and Chemnitz report on what’s in store for machine tool manufacturers and users.

“In most sectors, batch sizes are decreasing”, observes Prof. Dr.-Ing. Dirk Biermann, who heads the Institute for Machining Technology (ISF) at Dortmund University of Applied Science. “The demand is for machines suitable for handling small batch sizes, coping with several different processes, and ideally providing options for complete machining.” In some cases, they are intended to replace highly elaborate specialised machines: as an example, the ISF’s Director cites a machining centre that thanks to collaboration between a machinery manufacturer and a tool producer now enables gear wheels to be produced efficiently as well.

Multi-Purpose Machines are a Declaration of Independence
The trend towards the kind of multi-purpose machining centres that are able to cost-efficiently handle a broad portfolio of products with small batch sizes accelerated significantly during the crisis. “With a multi-purpose machine, you’re less dependent on particular products and sectors”, explains Biermann. “But there are still going to be specialised machines for large batch numbers.” However even when it comes to the classical representatives for large-series production, there is definitely an incipient trend reversal: in the automotive industry, for example, the multiplicity of different variants and drive concepts is increasing, as they arrive on the market in ever-shorter cycles. “Here, too, the requirement is for machines that are able to cope effortlessly with rapid changes in the components being manufactured”, says the scientist.

Energy-efficiency, too, is meanwhile playing a prominent role. Purchasers should consider not only the equipment capabilities themselves – such as using efficient drives, avoiding unnecessary load pick-up and minimising power consumption in stand-by mode. They should also think in terms of the process as a whole.

Sometimes it’s Worth Changing Tools
As an example from the field, Biermann cites deep drilling. “When the user does not have very exacting requirements for the surface quality of the drill-hole, he can use twist deep drills instead of a single-lip tool”, he explains. “They’re on offer as standard with a length-to-diameter ratio of 40.” The benefit, says Biermann, is that the twist deep drills can machine workpieces at a much higher feed rate (for example: 0.2 instead of 0.02 mm) – at a significantly lower cooling lubricant operating pressure (for example: 25 instead of the previous 80 bar). Changing a tool type not only cuts the cooling lubricant pump’s energy consumption and the machining time involved. “For deep drilling, in particular the enormous time savings achieved can lead to entire machine systems being rendered superfluous”, says Biermann.

With a view to sustainability, he recommends adopting a holistic approach, placing the process concerned in its wider context: for example, the hardness and mechanical strength of bainitic steels can be increased without any significant losses in toughness. Purposeful development of the alloy and the process involved, moreover, ensure that the costly and energy-intensive thermal treatment otherwise customary for tempering can be dispensed with. “The requisite mechanical strength can be achieved simply by cooling down from the forging temperature”, explains the professor.

Sustainable Cooperation with Forming Companies
When it comes to the issue of sustainability, Dortmund works closely together with the Institute for Forming Technology and Lightweight Construction (IUL). “We compress aluminium chips, which are moulded into profiles” says Biermann. “This enables us to achieve profiles with a mechanical strength amounting to 95 per cent of the original figure.” The benefit here is that smelting of the chips, which is otherwise required (and in the case of aluminium is highly energy-intensive) can be dispensed with.

All in all, the expert sees Germany as the leading nation in the field of sustainable, energy-efficient production technology, for which there is meanwhile a pent-up demand, not only among the newly industrialising counties. To quote Biermann: “Even high-tech nations like Japan are developing their energy-efficient machines primarily for the European market.”

The ISF’s Director, his staff and his students will be bringing themselves up to speed on the current international status in the sector at the EMO Hannover 2011. To quote Biermann: “At the world’s premier trade fair for metalworking applications, I expect to see primarily new developments and trends in terms of process integration, with enhanced energy-efficiency for machinery and processes alike. Lightweight construction in the automotive and aircraft industries will also play a significant role, as will virtual production planning.”

Cold-Forming Saves Energy
Prof. Dr.-Ing. Reimund Neugebauer, Director of the Fraunhofer Institute for Machine Tools and Forming Technology (IWU) in Chemnitz also expects the EMO Hannover 2011 to focus on resource-efficiency. He is in no doubt that forming technology overall is on an uptrend, thanks to material-efficiency, lightweight construction and higher mechanical strengths. The expert cites cold-forming as a good option for saving energy, since it obviates the need for energy-intensive heating processes. The users, on the other hand, have to operate with high press forces and concomitantly large amounts of energy. One remedy here is near-net-shape production using cold-forming, which saves numerous production steps and consequently energy as well The Fraunhofer IWU, for example, has developed a process for producing running gears. The people at Chemnitz for instance, roll toothing systems for car transmissions in a single step. In his view, the process has quite a lot in its favour:
1.        It ensures genuine manufacture of the final contour, utilising the raw material without creating chips.
2.        The forming process ensures optimum fibre distribution, plus improved acoustic and mechanical-strength properties.
3.        The production time involved is cut by more than 80 per cent, with concomitantly substantial cost savings.

Cold-forming, too, comes up against some limitations. “If gigantic press forces would be required for cold-forming, than hot-forming is the only viable option” comments Neugebauer. “The heat is, moreover, suitable for setting graduated mechanical-strength properties. In a sheet of metal, areas with high and low mechanical strength can be created, by means of appropriately selected cooling.”

Hot-Stamping: Recovering the Waste Heat
Energy can also be saved in hot-forming processes. As an example, the institute’s Director cites hot-stamping in bodywork production processes, which requires substantial amounts of energy for heat-up. “We’re tackling this issue with partners from the industrial sector in two ways”, says the pundit. “Firstly, alloys are being developed that do not need such high temperatures. Secondly, tools are being created whose waste heat during cooldown is fed back into the production process.”

Author: Nikolaus Fecht, a specialised journalist from Gelsenkirchen

Profile: Fraunhofer IWU
The Fraunhofer Institute for Machine Tools and Forming Technology (IWU) is a research and development institution working in the field of production science for automobile and machinery manufacturers. Around 400 highly qualified staff in Chemnitz, Dresden and Augsburg are engaged in researching their core competences of adaptronics/mechatronics, machine tools, forming technology, joining and assembly technology, and virtual reality. The focus here is on application-driven research and development.

Profile: ISF
The Dortmund University of Applied Science has been researching metal-cutting technology for almost four decades now at the Institute of Machining Technology. In 1983, Prof. Dr.-Ing. Ludolf Cronjäger renamed the faculty he had headed since its foundation (1972) as the “Institute for Machining Technology (ISF)”. Management of the ISF passed subsequently to Prof. Dr.-Ing. Dr. h.c. Klaus Weinert (1992 to 2008) and Prof. Dr.-Ing. Dirk Biermann (since 2008), who like their predecessor focus on research and teaching with all the important metal-cutting processes and the information technology environment involved: the bandwidth ranges from turning, drilling deep-drilling, milling, grinding and honing all the way through to abrasive blasting. The ISF possesses a staff of about 50, plus another 50 undergraduate assistants. One astounding statistic underlines the institute’s quality and reputation: outside funding finances around 80 per cent of the personnel costs.

EMO Hannover 2011 – the world’s premier trade fair for the metalworking sector
From 19 to 24 September 2011, international manufactures of production technology, “more than machine tools!” will be presenting their current capabilities at the EMO Hannover. The world’s premier trade fair for the metalworking sector will be showcasing the entire bandwidth of modern-day metalworking technology, the heart of every industrial production operation. It will be showcasing the very latest machines, plus efficient technical solutions, product-supportive services, sustainability in the production process, and much, much more. The EMO’s principal focus is on cutting and forming machine tools, production systems, high-precision tools, automated material flows, industrial electronics and accessories. The trade visitors to the EMO come from all major industrial sectors, like machinery and plant construction, the automotive industry and its component suppliers, aerospace technologies, precision mechanics and optics, shipbuilding, medical technology, tool and mould building, steel and lightweight engineering. The EMO Hannover is the biggest and most international meeting point for production technology anywhere in the world. The last EMO Hannover fair in 2007 was the venue for 2,120 exhibitors on approximately 180,200 m² square meters of net exhibition floor space, attracting more than 166,500 trade visitors from 80 different countries.