Gearing up for a faster tomorrow
A gear-cutting specialist company sets new standards in the factory by using specialised gear-hobbing machines | Experts estimate that every year up to two billion gears are produced worldwide. Gear production for transmission systems alone accounts for a massive number, for instance, considering approximately 87.3 million cars produced worldwide in 2013. And there are many other sectors of industry that use gears and splined shafts in their products. However, there is one factor that all branches using geared components have to contend with, an ever increasing number of customer demands.
Complex geometries, highly variable batch sizes, a large variety of product types and outstanding component quality, are all posing ever greater challenges for the gear cutting industry. How one can hold one’s ground in such a demanding segment of the industry is shown by Grimm GmbH, Gosheim, a gear cutting specialist with over 80 years of experience in the machining of gears and gearings.
“Approximately 25% of our production is for the automotive industry, in particular the oil pump, shaft and vacuum pump sectors. However, our company is also strongly represented in drive systems technology, where our product range includes everything from shearing machine shafts to shutter motor shafts. Every electrical motor that contains a shaft is of interest to us. On average, an approximate 20 million shafts leave our works every year”, characterises, Eugen Braunschweiger, joint MD, Grimm GmbH. Grimm produces approximately three million other geared components per year, with the applied know-how covering everything from turning the raw-part to gear-cutting and grinding it. The object is always the same, to produce a ready-to-install component.
“Our focus is on providing our customer not only with one step in the machining process but with a complete-machined component”, explains Braunschweiger. And the main focus is not on the production of pure turned parts. “We specialise in workpieces that have to be machined in a number of steps. This is where our strength lies”, states Herr Fritz, joint MD, Grimm GmbH.
Grimm GmbH invested in their first Koepfer machine almost 40 years ago. “Koepfer offers us exactly the right gear cutting machines, highly suitable for many types of workpieces and variety of batch sizes. We also try to keep the number of different machine labels on our shopfloor to a minimum. Another important point for us is our geographical closeness to Koepfer and the fast, excellent service this guarantees. He further adds, “Our partnership with them functions well as they are always willing to help realise even the most unusual wishes and ideas we might have regarding automation and workhandling.
In this respect, they meet our demands by offering us machines that are made to suit our particular requirements”, explains Braunschweiger. The most noteworthy point is the compatibility between the various Koepfer machines. For instances, all workpiece receptors can be used on all of their machines. Software, tools and even magazines are all compatible between machines. “Compatibility amongst our machines is of great importance for us. At the development stage itself we make sure that interfaces are created. For example, as many components as technically possible are the same on a variety of our machines. This ensures that the customer is not faced with the extra expense of stock duplications or with having to stock exchange parts,” explains Volker Eschle, sales engineer, Koepfer.
The training effort for the customer staff too is reduced when one works with machines from a manufacturer with a well thought-out machine platform philosophy like that of Koepfer Verzahnungsmaschinen. Over 200 machines in the field confirms the success story of Koepfer K160; and those responsible for it at Grimm’s are happy that the K 160 has also become a jubilee machine, with the organisation now having delivered the 200th machine.
There are reasons for this success. Stating those, Herr Bohner, departmental head, Grimm GmbH, comments, “The most significant aspect of K160 is its accessibility. Despite its size, it is easy to quickly reach all its important points. Its dimensional accuracy and reliability are also outstanding. Once a K160 is set up, it produces components of exemplary quality, without adjustment.”
Where machining times are concerned, the main objective is always the same: as fast as possible. The basic prerequisites for fast chip-to-chip times are high spindle speeds for the cutter and work axes. These features will allow the machine to take advantage of high cutting speeds but to make the manufacturing process truly efficient one also has to reduce the times for loading, unloading, setting and programming to their absolute minimum. Over the last few years users of the K160 appear to have these factors well under control.
Considering the fact that some years ago the machining of armature shafts took 20 to 25 seconds, K160 has been achieving eight – ten seconds for quite some years now. The dry, high-speed hobbing of planetary gears or the high-speed gear cutting on armature shafts using the “fly-hobbing” process, are as much a part of the reason for the success as is the possibility to use the tangential hobbing process to generate the gear teeth on worm wheels.
Grimm GmbH specialises in the manufacture of high-quality workpieces. “To produce high-quality components requires high- quality production tools. These are, primarily, the machines employed for the work, but also the measuring equipment that monitors and documents component quality. However, the key to achieve this quality with a degree of efficiency is the know-how of operators and setters. It is this interaction of different factors that results in the kind of component quality that makes our customers happy. If one of these factors were missing from the equation, we would not be able to achieve the high component quality our customers demand”, defines Braunschweiger.
One characteristic for which Grimm is noted is the company’s high degree of flexibility in the management of batch sizes. The machines are used for small batches and mass production alike. The company handles up to 3,500 different component types every year. This requires four to five setups a day for their gear cutting machines.
Machine from Koepfer provide them with the right combination of new software and drive technology that allows the customer to achieve a level of precision that has previously only been possible with grinding. Such quality makes the K160 also a viable proposition for the machining of components with special safety requirements, including those for the aerospace industry.
EMAG Holding GmbH