Michael Kocur is a marking scribe, polisher and contour cleaner at WSK. He learned his trade as a machine technician at the company in 1984 and has now worked at WSK for 35 years. His job is fine and finish machining, and he's responsible, among other things, for polishing the crankshafts. He accepts no ifs and buts where precision is concerned: "Precision is what the customer demands. We supply it."
Precision as a principle
Interview with Steffen Drechsler (Head of Crankshaft division) and Michael Kocur (Finish Machining)
Precision can be measured not only in tolerances, contours and processes. It must be lived out every day, with high-accuracy work, a passion for detail and an uncompromising determination to get everything exactly right, as a talk with the specialists at WSK makes clear.
glückauf ("glückauf" is the GMH Gruppe employee newspaper): Mr. Drechsler and Mr. Kocur, are you always careful to apply the highest precision in your work?
Steffen Drechsler: Very much so! Our components may be as long as 12 metres, but we still need the accuracy of a watchmaker during production.
Michael Kocur: Let's have a look at a crankshaft with a diameter of 450 millimetres. In these 450 millimetres, we can allow a tolerance of only four millimetres. On a shaft of 12 metres length, the lateral runout must not be more than 0.005 millimetres. And this is our normal, everyday business.
glückauf: WSK is a short-run specialist. What does that mean for your daily work?
Drechsler: It means that we are working every day on a different type of shaft. Thirty a year of the same model is a large production run for us.
Kocur: The exacting demands of our customers, the daily re-equipping of our workplace, ever new demands for tolerances and surface finishes – the precision of the technology used is not enough on its own, a human passion for perfection has to be added. Our employees must live out this precision – and that's exactly what they do.
"'We've always done it like that' just isn't an option any more."Michael Kocur Finish Machining
glückauf: Has production changed as time went on?
Kocur: Yes, definitely. Tolerances have become even tighter, surface finishes even better, and the hardness of the materials used has risen. Tiny defects which used to be acceptable are now a no-no! And this, of course, naturally affects our work, for people and for machines.
Drechsler: Take a look, firstly, at the machines: their accuracy is nowadays much better. The shafts reach the workplace with a maximum out-of-roundness of only two hundredths of a millimetre. Bearing alignment is also extremely good. This makes life easier for our employees, and we have become significantly faster.
Kocur: In production, for example, we sometimes work in pairs. The two employees must be the right ones, though, they have to complement each other. Our top-teams are receptive to the new and they know how they can optimise their work. "We've always done it like that" just isn't an option any more.
glückauf: What happens if there are minor inaccuracies?
Drechsler: If we make a mistake, the result is usually that the crankshaft can no longer be used. There are practically no chances of repairing it. Whether we're talking about insignificant, minimal errors or even just "cosmetic defects" – the customer will refuse to accept it.
Drechsler: Because then the end customer for the engine might have so many claims for spare parts or extended warranties that the expense could exceed the costs of the crankshaft. Everyone who works here knows that. And everyone knows how much these shafts are worth. Our colleagues and employees have respect for this and they work with great care on these shafts. Despite all the care applied, we still have technological target times for machining. And these times must be met, in fact, we need to be even faster. This, of course, also causes a lot of pressure.
WSK's core specialisations
- Drop-forging for heavyweight components such as crankshafts and connecting rods up to 3,500 kg
- Portal axles, gearwheels and brake disks (rail technology), separators (foodstuffs industry), elevators (offshore) and the key components of high-capacity engines
- Large-scale crankshafts up to 25 t for cruise and container ships, power-generation plants, compressors and pumps
glückauf: How does the final inspection look?
Drechsler: We have a large range of internal checks and inspections in place to detect any deviations immediately. And, in addition, we have our Quality Assurance system and an employee at the final inspection station who, after completion, inspects the entire shaft again. He cooperates very closely with Quality Assurance, he is extremely meticulous and he detects and removes, effectively under surgical-standard lighting conditions, even the very tiniest flaws. He gives the shaft its final polish before it goes into its crate for delivery.
glückauf: Is "meticulous" perhaps the best way of describing the work of these colleagues?
Drechsler: Yes, meticulousness is one thing, but a lot more is needed as well. The high-precision interaction of all the employees working on the production of the shafts, for example. Attention to detail alone is not enough to achieve this. You also need a passion for the best possible solution. Everyone working here is proud of our product and of making it here.
glückauf: Applying maximum precision in your job, every day, doesn't that have an effect on people's personal lives?
Kocur: People have their own special, very critical look, for instance, when tradesmen - painters, decorators, heating technicians and so on - visit the house. It's difficult to adjust when you're used to thinking in hundredths of a millimetre! Either you have precision in your blood, or you don't.
Wildauer Schmiede- und Kurbelwellentechnik
Our crankshafts have to withstand not only maximum stresses, they also have to be produced to accuracies of a few hundredths of a millimetre. In close cooperation with Schmiedewerke Gröditz, we cover the complete value chain, from the steelmaking, via the forging process, up to and including ready-to-install crank and eccentric shafts.
Steffen Drechsler is a Divisional Manager at WSK. He has been with the company since 1998, beginning as a CNC programmer, before later becoming head of the Production Planning department.