Downsizing is one of the trends in car making. An increasing amount of technology capable of enhanced performance is packed into the smallest space. To ensure this functions correctly in the engine or gear box, forming specialists from Feintool System Parts are in high demand. They too are consistently pushing technological boundaries and the limited space available for forming tools.
“There is no replacement for cubic capacity. Except even more cubic capacity.” For a long time this familiar quotation reflected the direction of travel for constructing engineers. Even in the 1980s, there were very few top-class cars with fewer than six cylinders. Until Audi started simply omitting one cylinder. Its engineers in Ingolstadt compensated for the loss of power with a turbocharger. The Audi 200 5T – the T stands for turbo – still managed an equivalent 170 HP and is thus seen as the founder of the downsizing trend today. Nowadays, the maxim everywhere is: Less is more. In countless models from all classes, cylinders and cubic capacity are being reduced to lower consumption and satisfy emissions requirements.
Why is that so important for Feintool? Because it means that in-built components also have to be smaller and lighter while simultaneously withstanding higher pressures and forces. Feintool System Parts produces around 22 million formed parts per year, particularly plate carriers for automatic gear boxes and clutches, such as dual clutch transmissions. In the design of these, manufacturers are also trying to make the construction space smaller and smaller. Plate carriers are reducing in size in turn in order to save weight. However at least the same forces, if not higher ones than ten years ago, are acting on a smaller surface area.
This means, at Feintool, as tool developers we are faced with a similar challenges as the powertrain engineers as automotive manufacturers. Modern gear boxes feature a higher number of revolutions per minute and place high demands on plate carriers, which have to be smaller, lighter, more stable and, above all, more precise. To achieve all of this, they are made from increasingly reinforced base materials.
The axial rolling tools that we use for the forming of plate carriers on our multiple-stage presses are very sensitive. If we process more reinforced base materials, the pressure on the active elements increases, while the parts are getting smaller and the forming rates are getting bigger. To simultaneously meet higher and higher precision requirements – five years ago saw tolerances of 0.3 mm, while today they are 0.1 to 0.15 mm – we are extensively optimizing the tools.
New tool steels and coatings for active parts
To keep the wear and tear of active parts low and hence precision high, Feintool System Parts manufactures active parts for axial rolling tools from modern, higher-quality alloys. In combination with new hardness specifications, they enable the absorption of greater pressure. The use of special coatings for active parts also reduces wear and tear. All of this leads to an increase in the service life of tools and compliance with the required tolerances.
Cooling concepts for active parts and components built into the design
During forming, friction is inevitably created between the tool and material – resulting in heat. The temperature in the press can increase from room temperature to up to 70 or 80 degrees Celsius. What happens when metal gets warm? It expands. To comply with the required tolerances, it is therefore essential to control the temperature as well as possible during axial rolling. Using minute cooling channels in the tool, we are now able to insert a precise quantity of cooling lubricant between the active part and the tool material and hence keep the temperature at a constant 40 degrees.
Tool stability through design-based optimizations
A simple solution for greater stability would be to make the individual tool elements somewhat larger and thus more stable. But unfortunately it is not as easy as that. Although multiple-stage presses are large in themselves, the construction space for tools is limited there too. On a press with a length of six meters and twelve steps, only 500 mm is available per tool (step). If we enlarge a tool element, it inevitably reduces the space available elsewhere. It is a question of finding the optimal balance. We have succeeded in improving the receptacles and bearing bolts of the rolls. This means that the pressure created can now be absorbed over a greater area. We have also precisely positioned cooling channels and lubrication grooves on the bearing pins to ensure that lubrication takes place across the entire area between the roll drill hole and bearing surface.
Quick exchange of active parts during production
Despite all optimizations, the service life of even the most modern tool will end at some point. To exchange active parts quickly during production, Feintool System Parts has for many years been employing a modular tool setup. This means that we can replace the element suffering from wear and tear alone and continue production within just a few minutes. This concept has proven its worth. However, retaining it for modern rolling tools is not a matter of course – during the design process, the increased complexity of the individual tool elements must be compensated to ensure that they can continue to be used and removed individually at any time like “pieces of cake.”
All in all, the downsizing of powertrain components means that Feintool must upgrade its tool making. But I am convinced that Feintool, just like Audi before it, can claim “Vorsprung durch Technik” (“progress through technology”) for itself and its customers.