The new method involves coating the silicon spiral, which contains a cavity to accommodate the stud, with a thin layer of gold and coating the metallic stud with a thin layer – just a few microns deep – of the gold-tin alloy. The coated stud is placed into the cavity in the coated spiral, and the assembly is heated in an oven so that the gold and alloy meld together and form a eutectic bond. The two watch components are thus joined together yet each one remains intact. Once the process is completed, watchmakers can easily place the assembly into the watch movement.
The new method is protected by two patents filed by Patek Philippe (WO/2020/148626 and EP3309624).
