QMT Features: March 2013
Time for measurement
3D measuring technology deliver the precise data  needed to manufacture high-end Swiss precision watches at IWC.

Tick tock, tick tock... tiny gears seamlessly interlock, effortlessly driving the inner workings of the clock and moving the second hand forward at just the right moment. The tiniest of details are responsible for the precise measurement of time. The demands of watch manufacturer IWC are particularly high. Measuring technology from Carl Zeiss ensures the efficient quality assurance of the coveted high-end Swiss watches.

“The measuring machines from Carl Zeiss deliver the precise data we need for our quality assurance activities with considerably less work than in the past,”  says Dr. Thomas Bregel, associate director of quality at IWC. With a clear focus on technology and engineering, IWC Schaffhausen has been manufacturing since 1868 exclusive watches that unite extreme precision and an exclusive design. The company enjoys an excellent international reputation thanks to its passion for innovative solutions and its pioneering technological spirit. As one of the world’s leading brands in the high-end watch segment, IWC produces not only sports watches such as aviator and dive watches, but also highly complex chronometers for the Haute Horlogerie segment. Several models feature special functions such as the “eternal calendar” invented by IWC, which shows the right date even in leap years. From time to time, the watchmakers work on a single masterpiece for several weeks.

Geometric accuracy
Production at IWC runs with the smooth precision associated with a Swiss watch. The company’s pursuit of perfection demands master craftsmanship, as well as outstanding specialists with years of training. A sophisticated quality management system is an absolute must. For a watch to show the exact time all the time, every one of the tiny parts must be matched geometrically perfect to each other. The tolerances for many of these dimensions are just two micrometers. To put this into perspective, the diameter of a human hair is around 100 micrometers. The special features of an IWC watch entail additional complexity in the design, assembly and quality inspection of these fabrications.

Until four years ago, IWC relied primarily on manual measurements in quality management and used various measuring gauges for the different models and sizes. Four years ago, IWC introduced a new process to enable it to make differentiated statements about the quality with minimal work – with Carl Zeiss Industrial Metrology at its side: “IWC Schaffhausen is a growing international company that combines precision, technology, perfection and uniqueness into its products,” says Bregel. “Over the course of our expansion, we therefore decided to rely on a partner in quality assurance that also lives these values,” states Bregel explaining the partnership with Carl Zeiss. The high demands of IWC are now reflected in an efficient quality inspection concept that covers tailored processes and suitable measuring machines, the appropriate software for the configuration of the measuring programs and an intelligently structured data management system.

Key to the selection of Carl Zeiss: the holistic approach. After all, there is much more to a measuring process than the measuring machine itself. According to Thomas Bregel, experience and development expertise are also key factors – something the optical experts from Oberkochen are known for. Growing partnership IWC has used coordinate measuring machines from Carl Zeiss since 2007 for incoming goods, initial inspection, and process and final inspection. They complement the manual testing equipment and, unlike the optical measuring systems of the past, are ideal for checking dimensions of height and boreholes. The partnership began back in 2007 with four O-INSPECT optical-contact measuring machines in the measuring labs of the two production sites in Schaffhausen and Neuhausen. The multi-sensor systems check the position and form features of the different watch parts. The machines start the measurement at the push of a button.

For a contact measurement, a stylus extends and scans the part on the basis of the specified measuring program. The acquired data is automatically used for the statistical evaluation. O-INSPECT checks the curves and contours optically by means of an integrated camera. In addition to O-INSPECT, the company has had two DuraMax coordinate measuring machines in operation since 2007. Because of their small footprint and insensitivity to temperature fluctuations, these robust systems can be used directly on the shop floor. The results are quickly available to production staff who can implement the corrections directly in production.

“With the new coordinate measuring machines, we are achieving maximum measuring accuracy,” adds Thomas Bregel. The new measuring concept has enabled IWC to increase its efficiency in quality assurance. The additional information about a part delivered by the measuring machines is beneficial for the correction of machine settings and tools. Furthermore, designers receive more accurate feedback on the feasibility of the parts they have designed: they not only learn if a part corresponds to design need, but also if it can be built. The measuring results also let workers know where deviations have occurred. These insights are used by designers to improve future designs.

3D measurements in minutes
The measuring results not only contain more information, but the new measuring concept also reduces the workload of quality assurance. A single machine is all that is needed now instead of multiple measuring gauges. The coordinate measuring machines complete complex 3D measurements in just a few minutes. Checking the position of two boreholes for a bottom plate or the flatness of a watch part is now child’s play.

The loading systems with the corresponding clamping equipment for the tiny parts also allow the preparation of parts for subsequent measurements while a measurement is running, thus increasing throughput and optimal utilization of the machines. Furthermore, measuring technicians can configure a new series on the basis of design drawings right at the start – before the first parts have even been produced. “This alone was a key aspect in our decision to go with Carl Zeiss,” remembers Thomas Bregel.

The improvements are not solely the result of the coordinate measuring machines; CALYPSO and PiWeb software are also part of the measuring concept. All measuring machines are programmed offline with CALYPSO. Depending on the part, the technicians specify the features being measured based on the CAD model. Once the program has been created, it can be launched at the push of a button by untrained personnel. Networking the machines and a holistic loading and operating concept simplify machine operation. This allows employees to flexibly measure each part with each of the six machines to reduce bottlenecking.

Web-based PiWeb quality documentation software connects the machines. All measuring results are managed in a central data pool. PiWeb supports the analysis, statistical evaluation, preparation and documentation of the data. “With PiWeb, we can easily and transparently design the measuring logs. This was vital to the acceptance of production staff,” declares Bregel. Moreover, the results can be used over the long run to optimize the design of future models. IWC has been developing value-retaining timekeepers for more than 140 years. Their complex functionality and outstanding user-friendliness are coveted by watch lovers who expect more from their chronometers than just the right time. They are no doubt waiting anxiously to see what developments the engineers from Schaffhausen have in store for the future. Regardless of what the future holds, the watchmaker will continue relying on Carl Zeiss for its quality assurance activities: “We are certain that the company will be able to help us master any future challenges we may encounter.”l
You can now view all QMT Magazine issues on your favourite tablet or smart phone.
Download the free Quality Manufacturing Today App from the Apple iTunes App Store or from QMT Magazine on Google Play.

Rob Tremain Photographer
Click above to see full page display and links to QMT articles.
Bowers logo
Control logo
Vision 2016 ad