Honing processes optimised together

Up until start of production and beyond, unit costs and gearing quality should develop and be stabi­lised as positively as possible. While the learning curve is extremely steep at the beginning, it does of course flat­ten off significantly after thousands of operating hours. This was the case at a European car manufacturer’s who, five years after purchasing several PRÄWEMA honing machines, decided in favour of a DVS system solution in line with the latest engineering stan­dard and has since reduced production costs quite considerably.

 

The project, which aimed to design the last process in the hard-fine machining of gear wheels more efficiently, was set up fol­lowing a visit to the customer’s. In concre­te terms, the target was to reduce process costs and increase the numbers of honed wheels produced daily. A team was formed to implement the project, made up of engineers from the machine manufacturer PRÄWEMA Antriebstechnik, ap­plication engineers from the tool system supplier DVS TOOLING and the project manager Alessandra Pimazzoni from DVS TECHNOLOGY EUROPE, the Munich bran­ch responsible for this key account custo­mer.

 

Mutual expectations and the distribution of tasks were discussed during a kick-off meeting at the car manufacturer’s plant. During the course of the meeting, DVS TOOLING was able to convince the manu­facturer to equip the machines selected for the test phase with the VarioSpeedDres­sing technology patented by PRÄWEMA. Since the customer’s machines are of a relatively new generation and had already been designed for the VSD technology, the PRÄWEMA engineers were able to carry out the conversion work on site.

 

The DVS system solution

 

Compared with the conventional dressing method using diamond wheels, Vario- SpeedDressing uses a dressing tool with defined cutting edges. The dressing tool, the VarioSpeedDresser® or VSD, is manu­factured using the finishing method DVS LaserCut specially developed by DVS TOO­LING. The result is an extremely homoge­neous structure for the cutting edge sur­face. An extremely high surface quality is created, which is transferred to the honing ring during the dressing process and thus finally to the workpiece. The second part of the DVS system solution involved the installation of honing rings from the “PRÄWEMA ORIGINAL” range from DVS TOOLING in the test ma­chines. Their high-performance ceramic material has been developed especially for use in PRÄWEMA machines, which is why the honing tools stand out on account of their consistently long service lives and high machining qualities. Adapting of the honing rings to the customer’s process was the task of the DVS TOOLING application engineers.

 

In order to ensure smooth work on site, the customer made a machine operator available to the DVS engineers for the en­tire test phase, made sure they had unli­mited access to the measuring chamber and a sufficient supply of raw parts. Ms Pi­mazzoni was responsible for making sure deadlines were kept and for the coordina­tion between the DVS companies and the customer.

 

Significant savings potential

 

The results were evaluated after the one-week test phase. The findings: there was a positive development in cycle times, dressing cycles, service lives and tool costs thanks to the new dressing tech­nology from PRÄWEMA and the original tools from DVS TOOLING. With one gear wheel, the dressing cycle was increased by the factor of 6, while the tool costs for this component fell by 85%. In the case of another component, cycle time was re­duced by 5 seconds while service life was doubled. In retrospect, the whole optimisation project was a complete success for the customer, who has been saving a low six-figure Euro volume ever since with original dressing and honing tools from DVS TOOLING.