Fixture comprising magnetic means for holding rotary symmetric workpieces

A fixture system comprising a holding part for holding a workpiece comprising ferromagnetic substances, said workpiece comprising a body with two ends and exhibiting along a rotary axis a symmetric shape with a radial dimension and with surfaces to be treated by means of a plasma assisted vacuum treatment process, said holding part comprising a magnetic means which generates a magnetic field with a magnetic force in the rotatory axis direction which is high enough for holding the workpiece if the workpiece is placed on a holding surface of the holding part in such a manner that one end of the workpiece is in contact with the holding surface of the holding part, the holding part further comprising:

• a fixture base, a magnet yoke comprising an opening, an outer diameter and an inner diameter, said magnet yoke being placed between a surface of the fixture base and the holding surface of the holding part in a manner that said opening is positioned in the opposite side to the fixture base, at least one magnet placed inside the magnet yoke in a manner that the at least one magnet is kept circumferentially at equal distance from the magnet yoke by a non-magnetic spacer;
• and
• the magnetic means of the holding part are designed and arranged in such a manner that the magnetic field lines of the generated magnetic field are at least largely confined to the space occupied with parts of the fixture system or body of the workpiece, so that a generation of side plasmas caused by the magnetic field lines during the execution of a plasma treatment is avoided.