Resource-efficient solutions for manufacturing

Lattice and honeycomb structures taken from nature are finding high-tech applications. © Photo: Fraunhofer IWU

How can companies save on materials and energy to increase their competitiveness? This is the question scientists at the Fraunhofer Project Group for Resource-Efficient Mechatronic Processing Machines RMV in Augsburg have set themselves. They have managed to make some components 55 percent lighter – with no loss of rigidity.

Companies and factories face relentless competitive pressures, as keenly priced products from Asia and other regions flood the market and put pressure on prices. In many cases, the only way for businesses to keep pace is by slashing the prices of their own products. But there’s a problem: the prices of the inputs for those products – i.e. energy and raw materials – are rising over the long term. If companies want to remain competitive, they have to optimize their resource consumption. In other words, they need to achieve the same result with less material and less energy. Not only can businesses then achieve a price advantage, but they can also protect the environment and put themselves at the forefront of lightweight manufacturing.

How exactly can they do this? This question is the focus of research for the RMV Project Group, part of the Fraunhofer Institute for Machine Tools and Forming Technology IWU and based at the institute’s Augsburg location. “In our view, future manufacturing processes will largely be shaped by how we optimize three different resources: energy, material and people. Our innovative solutions give our partner companies a competitive edge, which is our way of helping to greatly improve sustainability,” says the head of the project group, Prof. Dr. Gunther Reinhart. The scientists are working on numerous projects to support large, small and medium-sized companies. As a unit of Fraunhofer IWU and through close collaboration with the Institute for Machine Tools and Industrial Management (iwb) at Technische Universität München, the project group combines expertise in manufacturing and process technology with experience in energy and resource efficiency.

Saving materials with mesh and honeycomb structures

In the automotive and aerospace industries, the debate around resource efficiency is dominated by the topic of lightweight manufacturing. Lattice structures, such as those found in the spongy cancellous or trabecular bone tissue in the femur, are predestined to play a major role in this, since they are extremely rigid and strong while also weighing very little. But what nature has been employing for thousands of years is only just getting off the ground in industrial facilities. While it is already possible to produce lattice and honey comb structures economically using additive manufacturing processes such as laser sintering – in which a laser beam travels across a bed of powdered metal and melts individual particles to bind them together, building up the desired part layer by layer – up to now this has worked only with regular structures. The drawback to this method is that bending forces can build up when individual bars in the lattice come under significant stress. The Fraunhofer researchers have now adapted the structure to the flow of forces within the part – in much the same way as in the bone. The resulting part sidesteps stress issues and weighs 55 percent less with no loss of rigidity.

The Fraunhofer scientists have also found high-tech uses for honeycomb structures, applying them in the kind of sandwich designs that are found in nature in the cranial wall of some species of bird. The principle is to contain a lightweight honeycomb core within solid, rigid exterior layers. This material compound is considerably more stable than the sum of its individual layers. Until now, only flat or single-curved structures could be given a sandwich design of this kind. In the future, designers will enjoy much greater freedom, since the researchers have shown that the use of additive manufacturing makes it possible to take this approach and produce parts in any shape whatsoever.

FOREnergy – the energy-flexible factory

Manufacturing industry recognizes that materials, whether raw or refined, are a finite resource, but until now it has rarely regarded energy in the same way. That is likely to change in the future – at least in Germany, since the country has decided that no less than 80 percent of its electricity demand must be met with renewable energy by 2050. However, solar and wind power generation is subject to natural fluctuations. One approach sees large-scale power storage facilities smoothing out peaks and troughs, but power consumers will also have to play their part by matching their demand to power supply in a more flexible manner.

This is no big deal for domestic washing machines, which are cost-effective because they can generally wait until power is plentiful before running. But how can manufacturers increase the flexibility of their energy demand? This question is being tackled collectively by five universities and research institutions and 28 SMEs in the FOREnergy network, which is led by the RMV Project Group at Fraunhofer IWU. As a first step toward the goal of an energy-flexible factory, researchers are making energy consumption more transparent. How much energy does a factory consume, over what time periods, and at what levels? Next, the scientists feed the data from this load profile into an energy model, researching the relevant facilities and storage systems as well as various approaches to planning and energy management. To keep manufacturing economical, the experts are developing an evaluation method that predicts the consequences of adjusting demand to supply and compares these to the financial rewards on offer.

An interactive, virtual demonstrator breathes life into these ideas for energy-flexible factories and the possibilities they present. As well as selecting what weather conditions should apply in simulations of this model factory, users can choose from various annual scenarios to highlight the effect on power prices of generating an increasing share of electricity from renewables.