APPARATUS AND METHOD FOR CONTROLLING COATING LAYER IN PVD PLATING PROCESS
Provided is an apparatus for controlling a coating layer in a physical vapor deposition (PVD) plating process that forms a coating layer on a steel sheet with metal vapor by PVD. The apparatus for controlling a coating layer comprises: a crucible into which a molten material is introduced; an electromagnetic induction coil disposed around the outer periphery of the crucible to heat the molten material introduced into the crucible and form a molten metal to generate metal vapor from the molten metal; a power supply unit for supplying an electric current to the electromagnetic induction coil; and a control unit for measuring the impedance of the electromagnetic induction coil and controlling the electric current supplied to the electromagnetic induction coil so that the impedance is kept constant according to the molten material which is introduced into the crucible at a constant feed rate.
1 . An apparatus for controlling a coating layer in a physical vapor deposition (PVD) plating process in which a steel sheet is subjected to PVD with metal vapor to form a coating layer, the apparatus comprising:
a crucible into which a molten material is introduced;
an electromagnetic induction coil disposed around an external periphery of the crucible to heat the molten material introduced to the crucible and to form a molten metal to generate metal vapor from the molten metal;
a power supply unit configured to supply current to the electromagnetic induction coil; and
a control unit configured to measure impedance of the electromagnetic induction coil and to control the current, supplied to the electromagnetic induction coil, such that the impedance is maintained to be constant, depending on the molten material introduced to the crucible.
2 . The apparatus of claim 1 , wherein the control unit measures a resonant frequency of the electromagnetic induction coil to obtain the impedance of the electromagnetic induction coil.
3 . The apparatus of claim 1 , wherein the control unit controls the current, supplied to the electromagnetic induction coil, such that a heating value generated by the electromagnetic induction coil is set to be constant.
4 . The apparatus of claim 3 , wherein the heating value corresponds to an amount of power of the electromagnetic induction coil, and the control unit controls the current, supplied to the electromagnetic induction coil, such that the amount of the power of the electromagnetic induction coil is set to be constant.
5 . A method for controlling a coating layer in a physical vapor deposition (PVD) plating process in which a steel sheet is subjected to PVD with metal vapor to form a coating layer, the method comprising:
introducing a molten material into a crucible;
heating the molten material, introduced to the crucible, with an electromagnetic induction coil, disposed around an external periphery of the crucible, and forming a molten material to generate metal vapor;
measuring impedance of the electromagnetic induction coil; and
controlling current, supplied to the electromagnetic induction coil, such that the impedance of the electromagnetic induction coil is maintained to be constant, depending on the molten material introduced to the crucible at a constant feed rate.
6 . The method of claim 5 , wherein the measuring of impedance of the electromagnetic induction coil includes measuring a resonant frequency of the electromagnetic induction coil to obtain the impedance of the electromagnetic induction coil.
7 . The method of claim 5 , wherein the controlling of the current supplied to the electromagnetic induction coil includes controlling the current, supplied to the electromagnetic induction coil, such that a heating value generated by the electromagnetic induction coil is set to be constant.
8 . The method of claim 7 , wherein the heating value corresponds to an amount of power of the electromagnetic induction coil, and
wherein the controlling of the current supplied to the electromagnetic induction coil includes controlling the current, supplied to the electromagnetic induction coil, such that the amount of the power of the electromagnetic induction coil is set to be constant.