The dial is the star act in all mechanical watches, so it is vital that the design and finish satisfy the most exacting aesthetic demands. Its manufacture calls for all-round expertise in various techniques, such as embossing, polishing, decorating, electroplating and printing. At present, the IWC collection comprises over 100 dials, some of them extremely complex, all vying for the attention of watch devotees.
A cursory glance at the dial is all it takes to find out the time. Time displays are omnipresent today and go back all the way to the appearance of the first clocks with a gear train in around 1300. In a fine-quality wristwatch, however, the dial is much more than a background against which to display the time. It is also the face the watch shows to the world and needs to satisfy demanding aesthetic criteria. Its manufacture is complex and time-consuming: “Making a dial can
involve over 100 separate steps and calls for a wide range of techniques from embossing, polishing and decorating to electroplating and printing,” explains Max Werdermann, the man in charge of dials and hands at IWC.
For most of IWC’s watch families, the dial starts out as a brass disc. One of the main advantages of this copper-based alloy is the relative ease with which it can be worked. For the Pilot’s Watches and the Ingenieur family, the metal chosen is iron. Here, the dial is also the upper part of the soft-iron cage that protects the movement from magnetic influences. During the first stage of the process, special forming tools exerting a force of several dozen tonnes stamp the discs with the subdials for the chronograph, calendar, power reserve display and small seconds. Decorative patterns may also be stamped into the dial.
THE MATERIALS ARE HEAT-TREATED TO OPTIMIZE THEIR PROPERTIES
Finally, the discs are tempered in an oven at around 800 degrees Celsius. After cooling, they are reheated to a temperature just below their melting point. The hardening/tempering cycle can be repeated up to 15 times in succession. “The reason for the thermal treatment is to find an ideal balance between hardness and ductility. We need to optimize the material’s properties for subsequent processing, so as to avoid cracks and fractures,” says Werdermann, summing up the procedure. When the process is complete, the disc is punched out its final diameter. At the same time, the hole in the centre and the date window are added. The blank can now be ground to its final thickness of around 0.5 millimetres and polished. This treatment leaves it with a reflective, mirror-like surface.
"Brossage", as the process is known in French, is used to produce different types of finish
A BRUSH WITH METAL FIBRE BRISTLES GIVES THE DIAL ITS FINAL POLISH
Many dials have special decorations. After polishing, they are, therefore, treated, among other things, with a metal fibre brush. “Brossage”, as the process is known in French, is used to produce different types of finish. Sun pattern guilloche work, for instance, is recognized by the lines emanating from the centre point like rays of sunlight. It is found, among others, on the slate-grey dials in the Portofino family. And IWC tried its hand at circular graining on a dial for the first time with the Ingenieur Chronograph Silver Arrow. This scale-like form of polishing is otherwise used mainly as a decorative element on parts of the movement.
PRINTED MOTIFS ARE APPLIED USING AN ELASTIC PAD
The colour of the dial, of course, must not change as a result of contact with the air enclosed within the case. A transparent lacquer film is, therefore, applied to protect the surface against oxidation. This part of the process takes place in a clean room under conditions of constant temperature, humidity and pressure. Only then are the dials printed using the pad-printing process. With an elastic, silicon rubber pad – or tampon – the ink is transferred from the engraved recesses in the printing plate to the dial. Up to ten such plates – or clichés – are transferred to the dial one after the other. These include the IWC logo, the chapter ring and the numerals in the subdials, or the lettering reading “Automatic”.
THE DIAL’S COLOUR IS THE RESULT OF A DIP IN AN ELECTROLYTIC BATH
Colouring the dial is probably the most complicated stage of the entire manufacturing process. The method used is mostly electroplating. In an electrolytic bath, the dials are coated with the metallic ion of a more precious metal. The disc is subject to several consecutive treatments. For example, a dial is first nickel-plated to protect it against corrosion before it receives its colour in a series of subsequent stages. The process has proved its worth primarily for silver- or gold-plating. Nickel-plating, however, is useful for creating a wide range of black or grey tones. “The final colour depends on many different factors, such as the temperature or age of the bath as well as the voltage,” explains Werdermann. Achieving consistent results calls for all-round expertise and many years of experience.
SOME DIALS PUT IN A STOP IN THE VACUUM CHAMBER
But the suitability of electroplating for blue or brown tones is limited. For this reason, IWC decided to make use of physical vapour deposition (PVD). PVD is the ideal way to create extremely dense layers only fractions of a micrometre thick. To prepare the dials for the process, they are first electrolytically nickel- and gold-plated. After plating comes the PVD coating itself, during which the dials are placed in a vacuum chamber and bombarded with gaseous metal ions. The final colour depends, among other things, on the specific conditions of the process and the thickness of the coating. In the Portugieser Chronograph Classic Edition “Laureus Sport for Good Foundation”, the deep blue dial produced in this way provides a wonderful contrast to the gleaming stainless-steel case.
Colouring the dial is probably the most complicated stage of the entire manufacturing process
APPLIQUÉS PROVIDE A THIRD DIMENSION
The final stage in the manufacturing processing comes with the positioning of the appliqués. The tiny markers or numerals give the dials an unmistakable sense of spatial depth. The appliqués are produced using a variety of complicated techniques, given their final shape using a diamond-tipped tool and finally polished to a mirror finish. Depending on the model, they may also receive a luminescent coating. They are positioned using tweezers in pre-drilled holes and riveted to the dial. Some watches also have a flange. This collar-like rim is either press-fitted to the case or riveted directly to the dial. In the Portugieser Chronograph, it has quarter-second markings and thus enables highly accurate readings of elapsed time.
A WIDE RANGE: FROM THE SIMPLE TO THE HIGHLY COMPLEX
The current IWC collection comprises over 100 different dials. These run the entire gamut from the simple faces found on the Pilot’s Watches to extremely complicated displays. We frequently encounter dials on which the numerals are a different colour from the rest of the face. The blank first receives the basic colour and is then completely covered with a coat of protective varnish. The numerals are subsequently milled down to the brass, and the entire dial is electroplated once again.
“During the second electroplating process, the metal ions are deposited only on the exposed surfaces of the brass. The rest remains untouched,” explains Werdermann. The Pilot’s Watch Chronograph Edition Antoine de Saint Exupéry, for instance, has a brown dial, while the subdials are rhodium-plated at a later stage.
With the Portofino Midsize Collection, 2014 also saw the return of mother-of-pearl to IWC. It is obtained from the ground and polished shells of the pearl mussel. For these dials, too, the basic disc is made of brass. The surface has a 0.2-millimetre-thick coating of mother-of-pearl. Its patterns give the dials a striking, optical depth. The spectacular dial is made even more exclusive by the addition of diamonds. The precious stones are individually riveted to the dial in special settings known as “chatons”.
FOR THE SPECIALISTS FROM SCHAFFHAUSEN, NOTHING IS TOO MUCH TROUBLE
IWC’s watchmakers are perfectionists. And they shun no effort to bring a gleam of pleasure to the eyes of discerning watch devotees. An example of their commitment can be found in the Ingenieur Constant-Force Tourbillon. In this timepiece, the surface of the moon is lasered into the tiny brass disc before it is PVD-coated with platinum. It is to this painstaking process that the lunar surface owes its realistically three-dimensional appearance.
The Ingenieur Perpetual Calendar Digital Date-Month has another sensational feature. Mineral glass discs that have been PVD-coated to give them their unusual smoky colour cover three of the subdials. They are complemented by luminescent appliqués and an unusually high number of printed details. “We often invest many months in the search for the perfect manufacturing process,” says Werdermann in summary. And it is these seemingly insuperable challenges that spur the specialists at IWC on to ever-greater achievements.
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