LIGA - Mimotec SA by huangyuarong



                  In a                                                                                                             of its Own
    New technologies are the catchword for the modern era in watchmaking.
    liGa is the newest technique for creating flawless movement components.
                                                                                                                                                                                                                          A mask placed in the X-ray machine in Karlsruhe.

     by ElizabEth DoErr

                                        H. Moser & Cie.’s gold escapement features
                                        gold LIGA components, an industry first.
                                                                                                                                                        A 3-D rendition of the synchrotron light facility in Karlsruhe.

                                                                                                                                                                                                                          An X-ray mask in Karlsruhe.

     n 2005, after three years of         research institute, developed
     experimentation, H. Moser &          LIGA, the new process for man-
     Cie. introduced the first wrist-     ufacturing microproducts. Karl-
watches made with escapement              sruhe’s research center currently
parts in 23.5-karat hard gold man-        employs more than 3,800 people,
ufactured through the LIGA pro-           1,420 of whom are scientists.
cess. Now, many watch firms are           Over the years, this gargantuan            Dr. Pascal Meyer in a Karlsruhe clean room.
researching this innovative, high-        research institute has accounted
tech and potentially revolutionary        for more than 1,800 patents, reg-
method of making movement com-            istered designs, and patent ap-                    The LIGA process
ponents, first developed largely for      plications.The center is divided           The word LIGA is a German
medical applications twenty years         into twenty-four institutes, one           acronym that stands for lithog-
ago in Karlsruhe, Germany.                of which is the Institute for Mi-          raphy (Lithografie), galvanic
    Forschungszentrum Karl-               crostructure Technology (IMT),             (Galvanisierung), and plastic
sruhe, a government-sponsored             where LIGA was born.                       molding (Abformung).                               This large machine generates the X-ray light needed to                            LIGA parts after exposure to X rays in Karlsruhe.
                                                                                                                                        expose the tiny LIGA parts.

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      Let’s start with the L           tography, which uses a gummy          leaving behind the structure of
The lithographic process is            substance. In fact, the light that    the non-irradiated plastic as the
perhaps one that might be famil-       is used at the Karlsruhe institute    primary structure.
iar as an artistic medium, used for    is actually X-ray light supplied by
copying and printing. Devised by       a synchrotron source (an electron                   The G
Alois Senefelder in 1798, lithog-      centrifuge), allowing low distor-     The galvanic part of the LIGA
raphy is mainly used for transfer-     tions due to optical effects and      acronym can be better described
ring something such as text or art     rapid exposure.                       with a synonym: electroform-
onto a smooth surface.                      The X-ray lithography used       ing. Though galvanics are widely
     The early principle was simple:   here—a type of microlithography       used in watchmaking to seal and
A sticky, water-insoluble material     —is a method that can structure       beautify components made of
was applied to a limestone as the      material on an extremely fine         various metals, this is not what
image. A mixture of gum arabic         scale. For the record, elements       makes a LIGA component. In the
and an acid was used to etch the       smaller than ten micrometers are      watch industry, galvanics are used
stone and make it phobic to ink.       considered microlithographic,         for plating by depositing a thin,
When ink was added, it adhered         and smaller than 100 nanome-          metallic layer onto an existing
to the sticky image, while from        ters are nanolithographic. LIGA
the negative image it could just       components are considered mi-
be washed away. Then the image         crocomponents.
was transferred to paper by press-          LIGA components begin
ing the stone onto it. Naturally,      with an X-ray mask that con-
this works the other way around        tains the precise shape or shapes
as well, making the positive nega-     of the parts to be manufactured
tive and vice versa.                   by means of a CAD system. The
     Modern lithography, used for      mask has a carrier transparent to
just about any mass-produced item      the light, which can be made of a
with print on it, such as posters,     very thin metal such as titanium,
books, credit cards, and CDs, now      beryllium, or glass. The synchro-
greatly depends upon photographic      tron light is used to “transfer”
processes that include exposure.       or “expose” the structural infor-
     The LIGA process uses light       mation onto a layer of polymer.
for stabilization, unlike the pho-     Then a solvent is introduced,
                                                                                   The “lapping” process at Mimotec

148                                                           march 2007INTERNATIONAL WATCH

Quality control at Mimotec                                Mimotec SA in Sion, Switzerland                      Mimotec employs 25 people in its Sion factory.                      A Mimotec wafer

component. Electroforming is        with a main focus on nickel, cop-        The first firm to use the         ket. Because the components are                  Until now Mimotec has re-       of gold, and one of them likely
actually component growth in a      per, gold, nickel-cobalt, nickel-    LIGA process for watch-industry       made in batches on a wafer using             mained the first company able to    has to do with the fact that there
plating bath atom-by-atom until     phosphorus, and nickel-iron.         purposes was Mimotec, a com-          the photo mask technology, tool-             offer LIGA components to the        are better materials available to-
it reaches the desired thickness.       Today, LIGA is used to man-      pany name short for Micromold         ing costs are far lower than with            watch industry, even beating out    day for reducing friction. How-
     The spaces generated by the    ufacture microcomponents for         Technology. Dr. Hubert Lorenz,        conventional stamping tools. The             the LIGA process’s own inventor.    ever, Lange’s idea propelled his
removal of the irradiated plastic   many industries just in this way.    at the time a doctoral candidate      process allows parts to be manu-                                                 visit to Karlsruhe: He wanted his
material can now be filled with a       However, the A in LIGA           at Lausanne’s École Polytech-         factured quickly, thus eliminat-                    Research center              escapement components to be
metal thanks to the electroform-    (plastics molding) can also be       nique Fédéral, founded the in-        ing one major problem among                         goes commercial              manufactured in solid gold using
ing part of the process. Since      utilized to make tools of nick-      novative little company in 1998       Swiss suppliers: late deliveries.            The marketability of LIGA in        the LIGA process.
the layer thickness here is much    el and nickel alloys for use in      with engineer colleague Nicolas       Quick delivery also meant that               the watch industry remained un-          This was interesting, for un-
larger than commonly found in       plastics and injection molding,      Fahrni. Lorenz’s idea was ground-     parts could be obtained quickly              important to Karlsruhe’s research   til then LIGA components had
the galvanic coatings of a watch    an important step in low-cost        breaking for watchmaking.             for prototyping and testing. In ad-          giant until one fine day in 1998    only been made in nickel, nick-
component, the variety of metals    mass production (think Swatch            Using a recipe of an SU-8-        dition, the wafer element of such            when Dr. Jürgen Lange showed        el-cobalt, and nickel-phospho-
and alloys is somewhat restricted   cases). For metal watch compo-       based photo-sensitive epoxy de-       batch production theoretically               up at the door.                     rus alloys. Gold was not a metal
                                    nent production, however, the        veloped by IBM, he developed a        guarantees that the first piece will             Lange was busy founding
                                    A is not used.                       much more cost-effective system of    have the exact same quality as the           a new luxury watch brand in
                                                                         direct LIGA in order to manufac-      thousandth piece of any given                Schaffhausen. He envisioned his
                                            Enter Mimotec                ture precise microcomponents for      run, ensuring constant quality.              new brand, H. Moser & Cie., to
                                    LIGA—or direct LIGA, as this         medical and watch industries. This         Mimotec can only offer                  feature very special movements
                                    shortened process without injec-     cost-effectiveness was assisted by    components made by the di-                   and a number of elements not to
                                    tion molding is known—is perfect     the fact that Mimotec uses an in-     rect LIGA process in nickel                  be found elsewhere. One of the
                                    for creating horological micro-      expensive ultraviolet light source    or a nickel-phosphorus alloy.                unique elements he had dancing
                                    components in very high quality.     for the exposure process, as op-      However, these components are                around his head was based on a
                                    In stark contrast to wire spark      posed to the expensive X-ray light    hard, stable, and nearly friction-           vintage tradition of solid gold
                                    erosion technology, LIGA com-        that Karlsruhe’s IMT uses.            free thanks to their extremely               watch movements. Lange wanted
                                    ponents are perfect every time           Lorenz’s idea took off. Not       smooth vertical walls. The qual-             to make escapement components
                                    and require no finishing. There      only was this technology superb       ity and properties of these com-             of pure solid gold.
                                    are no burrs, since they are not     in terms of quality, it was a pre-    ponents are without a doubt the                  Certainly there is a reason
                                    cut, and therefore do not need to    cise technology associated with       main reason that many compa-                 that tricky movement compo-
                                    be trimmed or polished to get the    low costs in many different ways,     nies are currently exploring and             nents such as those found in the
Dr. Hubert Lorenz, founder
and CEO of Mimotec.                 desired level of finishing.          and Mimotec cornered the mar-         utilizing them.                              escapement are no longer made       The clean room at Mimotec

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                                                                                                                                                                                                            The ABCs of LIGA
                                                                                                                                                                                                            “our only issue is the market,”
                                                                                                                                                                                                            says Mimotec co-founder hubert
                                                                                                                                                                                                            lorenz, winner of the Swiss
                                                                                                                                                                                                            Economic award in 2001. “We
                                                                                                                                                                                                            are interested in the price, qual-
                                                                                                                                                                                                            ity, and delivery we can offer
                                                                                                                                                                                                            our close to fifty customers in
                                                                                                                                                                                                            the watch industry. the market
                                                                                                                                                                                                            demands that we be cheaper
                                                                                                                                                                                                            and more precise. With the sys-
                                                                                                                                                                                                            tem we have devised, all of this
                                                                                                                                                                                                            is possible.”
                                                                                                                                                                                                                  Many of Mimotec’s clients
                                                                                                                                                                                                            are smaller, innovative compa-
The Microworks team: Georg Schwarz,                               Dr. Joachim Schulz at Karlsruhe’s Forschungszentrum.                                                                                      nies who simply cannot afford
Dr. Joachim Schulz and Dr. Pascal Meyer.                                                                                                                                                                    to invest in tooling and stamp-
                                                                                                                                                                                                            ing when developing small, elite
                                                                                                                                                                                                            series. Direct liGa is a grand
                                                                                                                                                                                                            technology for just such pur-
                                           it the proper hardening proper-             It is no secret that all of the ma-   organizations able to manufacture            “I am interested in verticaliz-   poses. With almost no tooling
                                           ties. This new hard gold is twice      jor groups and independent watch           their own LIGA components.               ing our facility,” Lorenz explains.   costs, a new complication can
                                           as hard as regular gold at 150-        brands active in the luxury segment            “That was simply a matter of             “LIGA was born in Karl-           be developed and tested quickly
                                           160 Vickers, while normal gold         of the watch industry have used or         time,” Mimotec’s Lorenz says in          sruhe,” Schulz explicates. “And       and easily.
                                           can be found at about 70 on the        experimented with components               answer to the question concerning        uses for LIGA will continue                 and Mimotec’s success
                                                                                                                                                                                                            speaks for itself: Starting in
                                           Vickers scale. Above and beyond        manufactured by the LIGA process.          possible new competition from the        to evolve here at the research        1998 with only two employ-
                                           that, Lange also found a way to        The benefits of certain components         industry’s major players.                center. We are excited to be          ees, the company has grown to
                                           specifically harden the walls          manufactured this way are just far             For the moment, however, the         working so closely with the watch     twenty-five people at its Sion,
                                           exposed to mechanical wear             too great not to. However, not all         playing field is unevenly divided        industry and we look forward          Switzerland, facility, only very
                                                                                                                                                                                                            few of which are actually trained
                                           by an additional factor of three       the components used by the watch           among the two major players, Mi-         to cooperating with these in-         beforehand. Most learn at
                                           by subjecting the parts to local       companies are as experimental              motec and Microworks. As it would        novative companies on projects        Mimotec to perform the neces-
A heart cam manufactured by direct LIGA.
                                           ion implantation.                      and cutting edge as Ulysse Nardin          seem, Microworks will continue to        that we are only beginning to         sary steps to complete the pre-
                                                                                  would sometimes have its audi-             lead the way in devising new alloys      imagine. We will put all our sci-     cise nickel or nickel-phosphorus
                                                                                                                                                                                                            components, the only materials
                                                     Microworks                   ence believe. That innovative little       for direct LIGA, while Mimotec’s         entific know-how and the con-
                                                                                                                                                                                                            with which Mimotec’s liGa pro-
                                           Spurred on by the success and          company dabbles in just about ev-          Lorenz is turning his attention even     siderable resources behind us         cess can work.
                                           interest shown by the luxury           ery new technology available, and          further to other new technologies        into progressing and beautifying            the first step is to design the
                                           industry in new and interesting        was certainly one of the first to help     such as silicon.                         watch technology.”               C    photo mask, which three design-
                                           technologies, a privatized com-        itself to the benefits of Mimotec’s                                                                                       ers spend their days doing. the
                                                                                                                                                                                                            photo masks then undergo ultra-
                                           pany has emerged from the re-          nickel-phosphorus escape wheels              Direct LIGA escapement wheels by Mimotec                                     violet lithography to produce
                                           search center formed around the        for use in cutting-edge watch move-                                                                                       wafers with the parts’ negative
Mimotec can even manufacture
two-level parts.                           nucleus of the main three human        ments such as the Freak.                                                                                                  in SU-8 epoxy. then follows the
                                           proponents. Microworks, as it is            LIGA is simply a cost-effec-                                                                                         electroplating step, or the “G”
                                                                                                                                                                                                            in liGa. at a wet bench, the SU-
thought to work well with me-              now called, is headed up by phys-      tive way of manufacturing better                                                                                          8 and the wafer are dissolved,
chanical LIGA parts. However,              icist Dr. Joachim Schulz, aided        components, be they innovative                                                                                            leaving behind the desired micro-
the research center’s scientists           and abetted by Dr. Pascal Meyer        in shape, form or function or not.                                                                                        components, which are then
took on the challenge, and ac-             (process engineer) and Georg           Though not officially confirmed,                                                                                          ground and “lapped” to get
tually came up with a hard gold            Schwartz (machine developer).          watch industry giants Rolex and the                                                                                       the exact thickness desired. the
                                                                                                                                                                                                            final step comprises only inspec-
alloy that allowed itself to be            The three enthusiastic scientists      Swatch Group have also recognized                                                                                         tion and quality control. Finally,
electroformed: 23.5 karats pure,           make a good team, ready to ex-         this technology to be a highly ben-                                                                                       the components are ready to be
the gold is only blended with              plore new territories within the       eficial one, even reportedly found-                                                                                       added to a movement.
cadmium and arsenic to allow               watch industry.                        ing departments within their own

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