It was near impossible to absorb the worldwide economic crisis at the end of the last decade. The automobile industry was especially affected and saw its growth dwindle away in the rear view mirror. As part of the supply sector, spring makers took a very hard hit. Yet the situation has turned for the better: ever since car makers witnessed a record last year, suppliers are receiving an influx of orders.
Automobile sector steers towards new records
The spring industry’s well-being is highly dependent from the automobile sector. According to German industry association Verband der deutschen Federnindustrie e.V. (VDFI), 62 percent of buyers can be found in the sector, alongside suppliers. The current outlook and figures thus are a reason for joy. Last year, automobile production grew 11,5 percent to 12,98 million in Germany and rose 3,5 percent to 80,27 million automobiles worldwide. „Never before have so many cars been produced in Germany, never before have so many been exported. The domestic market is also growing“, exults Matthias Wissmann, president of car maker association VDA. Here, Germany is one of the worldwide leading countries.
Asia and North America are the largest markets for car makers. Western Europe is currently playing a different role. By 2015, car sales in Western Europe may account for less than 20 percent of global sales. Nonetheless, the signs of the times all show towards growth: for the current year, the „CAR University Duisburg-Essen“, forecasts worldwide automobile production growth of 5,1 percent – another new record for the sector.
A boon for suppliers
This naturally is a boon for suppliers such as spring makers: trailing the car industry, turnover of car parts, components and accessories last year climbed 12,3 percent to 12 billion euro. In Germany, total spring production is nearly 500.000 tons a year. Around 180 companies account for a turnover of two billion euro.
Without springs in various shapes and sizes, cars wouldn’t be able to function. Whether upholstery or suspension – this component is always on the road. Suspension, for instance, is part of the chassis. Springs allow tires to stay in contact with the road, despite bumps and unevenness, whilst the rest of the vehicle is kept steady. And only a well-sprung seat is comfortable. Thousands of springs can be found in a car. Valve springs hold and open inlet valves for the fuel-air mixture and the exhaust valves for exhaust fumes and combustion products.
Electronics industry electrifies spring makers
In addition, the spring market is also jump-starting developments in the electronics industry, which accounts for 13 percent of shipments and is the second-largest buyer of springs in Germany, according to the VDFI. Springs are an important part of turbines and isolators used to generate electricity. The electronics industry is also heading towards new records. „Adjusted for price effects, the production output of electronics companies improved by ten percent in January 2012 year over year“, reports German electronics association ZVEI. Even the record levels of 2008 are being surpassed by the sector.
Engineering is the third-largest market for the springs sector. Ten percent of goods are shipped to engineering companies. Where machines have to resist force, technical springs are not far away. Mechanical engineering is also doing very well – last year, production volume grew by 14 percent. „Capacity utilisation has risen from an absolute low of 67,5 percent in July 2009 to 88,7 percent“, explains Dr. Thomas Lindner, president of mechanical engineering association VDMA. Production volume is expected to grow additional four percent this year.
Facing temperatures and force
Diverse sectors such as medical technology, the food, building and rail industry, optics, toys, watches and office equipment are also large buyers. Demand is high for cold- and hot-formed springs, such as compression springs, parabolic and trapezoidal springs, conical springs, pressure, tension, torsion and leg springs, as well as disc and flat spiral springs.
A technical spring is designed to withstand pressure and force, balance them or pass them on. By contrast, a spring in a ballpoint pen hardly has to cope with such mechanical stresses at all. At the other end of the scale is the manufacturing industry, where components have to withstand tremendous forces. Yet they not only have to withstand force. Temperature fluctuations, such as those found in the steel industry, can also add stress to the materials used for a spring. In terms of high-tech, flat wire springs help satellites perform their tasks.
Springs for humans
Even the human body itself needs springs. Dr. Werner Roehrs KG is developing a spring for bone lengthening. „After the bone has been artificially split, the space between the two segments has to be pushed apart by a spring, in order to support the bone’s lengthening process“, explained Dr. Philipp Koepff, CEO of the Dr. Werner Roehrs KG, to newspaper „Allgaeuer Zeitung“. Apart from the size and strength, the material used for such a spring is of utmost importance, „so that the body has no natural immune response“.
As numerous as the applications, so diverse are a spring’s properties. Not only does a spring have to live up to its dampening behaviour. Customers often ask for corrosion and temperature resistance, as well as perhaps electrical conductivity. A standard spring, as manufactured by Dr. Werner Roehrs KG, is used in environments with temperatures of up to 80 degrees Celsius. The company, based in Sonthofen, Germany, also manufactures valve springs for the automobile sector out of oil hardened and tempered spring steel wire for use in applications with temperatures of up to 120 degrees Celsius. Springs made from stainless spring steel will withstand corrosion. Spring wires made from copper or copper alloys have good electrical conductivity, making them predestined to be used in electronics. Springs made from nickel-based alloy are especially resistant against high temperatures and corrosion.
Machinery for high quality
In the best of cases, springs not only possess numerous favourable characteristics, but also differ in size and form. Flat wire springs are often demanded for small installation spaces, as they offer higher energy absorption than round wire compression springs.
Companies that want to jump upwards in the market need to out-do their competition and offer high-quality products. A broad machinery base is essential. Fortuna Federn Austria is a supplier of machines for manufacturing springs. The company develops spring lathe coilers, its model WIM CNC is controlled by an automatic servo and can be equipped with a wire catching system for the first coil. It can be used for the cold or hot production of right and left coiled cylindrical and one-sided conical compression, extension and torsion springs, different wire forms and double torsion springs. According to Fortuna Federn, the machine pulls in, coils and cuts automatically.
Focussing on the value chain
Semiautomatic hydraulic looping machines are needed to produce German and English loops on extension springs. Semiautomatic servo-controlled wire bending machines are used to make various bending parts from wire. Wire trimming machines are also important. They cut springs, springs ends and spring legs. Grinding is a cost-intensive part of the manufacturing process. One method to reduce grinding is to cut a wire diagonally, thereby reducing costs and workload.
Yet the focus is not only on the individual steps in the process. One trend is towards an analysis of the entire value chain. VDF Vogtland Federntechnik is placing its bets on „lean spring production“. „Processes have to be looked at and optimised“, states Thorsten Schrotsberger, project manager VDF Vogtland Federntechnik, in trade journal „Quality Engineering“. All quality-relevant processes can be continuously planned, controlled and evaluated during production. „On the one hand, one of the important elements is flow-production, which avoids waste of resources due to overly high inventory levels or standstills due to low volume production. One the other hand, the zero-error strategy comes to grip, which detects errors and helps avoid them, if possible before they even occer“, adds Schrotsberger. This enables a continuous production flow, even in the case of short production cycles and low volumes. „Stocks and storage areas are also optimised, so that intermediate storage is reduced to a minimum“.
Process optimisation and complaints management
Integrated complaints management is also part of VDT Vogtland‘s process optimisation. Here, the system delivers up-to-date analysis and figures, which help detect common mistakes and avoid them in the future. Customer complaints can be prioritised, so that „not only faulty shipments, but also the entire process can be globally optimised “, says Schrotsberger. The defect rate can be minimised for the long-term.
Introducing a quality management system was a worthwhile investment for VDT Vogtland Federntechnik GmbH, especially in view of its customer structure, as car makers, which account for half of all orders, change their models in an increasing rate. „Batches of vendor parts per car type are decreasing, the amount of spring variants is increasing “, explains Schrotsberger in „Quality Engineering“. Small production batches, lots of ramp-ups and high pressure to innovate pose challenges for the quality of products and processes.
Buyers expect sustainable processes
Efficient production processes are one formula for success. In the last few years, another formula has established itself. Buyers are increasingly paying attention if a supplier is utilising an eco-friendly and sustainable production process. Manufacturers who react accordingly are set to profit, not only in view of the customer. Rising prices for energy and raw materials demand sustainable production – apart from the fact, that the environment is kept clean.
These were all good reasons for Renzing GmbH and Vogtland Federntechnik to have themselves certified. TUEG-NRW certified the group with the environmental standard Norm ISO 14001. It is now especially important „to train employees and that all superiors set an example“, underlines Klaus Halverscheidt, who worked closely on the project for the management. Companies that want to stay on the road of success can’t take a shortcut past the environment. Business and ecology are increasingly growing together. Here, the spring industry is another case in point.