In order to prevent undesirable friction processes or rapid wear, the microscopic components of high quality watches must have optimal surface properties. This also applies to the pivots of the various shafts in the movement. If their quality suffers, then this would quickly lead to the clock noticably gaining or loosing time. These components are traditionally manufactured using a mechanical turning process. However, chip formation, heat effects and tool wear lead to large variances in quality. In addition, conventional lathes aren't always able to reliably reproduce the often challenging geometries, for example at the transitions. To avoid rejects, a renowned high end watch manufacturer from Switzerland is now having the pivots manufactured using a laser turning process. This process was developed by GFH GmbH, headquartered in Deggendorf. The system uses an ultra short pulse laser with special trepanning optics, which is able to produce even the smallest radii or undercuts without wear and without chip formation. Blanks made from a wide variety of steel grades can be machined, as can ceramic or diamond materials which are difficult to machine with conventional means.
Manufacturing a high quality mechanical timepiece demands the highest possible precision and focus, both from the machines used and from the watch makers. The work must be performed to very tight tolerances of +/- 0.002 mm. These requirements apply to all individual components of a mechanical movement: If the radius of a component is too large or the surface is too rough, for example, then the resulting friction could lead to faster wear and ultimately to the watch not keeping the correct time.
In addition, the geometries required for turned and roller-burnished parts cannot always be produced with micrometric precision on conventional machining systems, leading to rejects. In particular, undesirable side effects such as chip formation and heating result from contact between the tool and the work piece. Watch manufacturers are also faced with the problem that the high strength and stainless steels and alloys which are essential for a high quality watch are difficult to machine or cannot be turned at all, since they have a high level of mechanical stability. This led to the partnership between the Swiss watch manufacturer and the German laser machining specialist GFH GmbH, in order to utilise the potential of laser based micro machining for watch manufacturing for the first time. GFH was already tasked with manufacturing 2D precision components in 2016. The good results and the special trepanning optics used by GFH immediately suggested continuing the joint effort. Now the Swiss company has contracted GFH to manufacture the challenging pivots using its proprietary laser turning process, contactless and without chip formation.