Continuous plating apparatus

1. A continuous plating apparatus capable of continuously plating workpieces transferred through a plating tank while continuously supplying power to the workpieces, the continuous plating apparatus comprising:

a computer system coupled to the continuous plating apparatus to control operation of the continuous plating apparatus;

one or more workpieces, a plurality of cathode relay members, and a plurality of power supply units, wherein, when a number of the one or more workpieces simultaneously transferred in the plating tank in a completely immersed state is N in a workpiece transfer direction, (N+1) cathode relay members that extend in the workpiece transfer direction, and (N+1) power supply units are provided outside the plating tank;

a set of opposing anodes that extend in the workpiece transfer direction, the set of the opposing anodes being provided in the plating tank;

a plurality of anode terminals of the power supply units connected to the set of opposing anodes; and

a plurality of cathode terminals of the power supply units connected to the plurality of cathode relay members;

wherein the computer system includes a period calculation portion that calculates a partially immersed period L/V based on a length L of the workpiece being extended in the workpiece transfer direction and a constant transferring speed V of the workpiece in the workpiece transfer direction,

wherein power is supplied to each of the one or more workpieces transferred in the plating tank from a corresponding power supply unit among the plurality of power supply units through a corresponding cathode relay member among the plurality of cathode relay members,

wherein each of the power supply units controls a current to be supplied to the workpiece under constant current control at a constant current Is when being transferred in the plating tank in a completely immersed state, under current gradual increase control to vary from zero to the constant current, Is, in the partially immersed period when the workpiece is carried into the plating tank in a partially immersed state, and under current gradual decrease control to vary from the constant current, Is, to zero in the partially immersed period when the workpiece is carried out from the plating tank in a partially immersed state;

wherein a current of the current gradual increase control flows through the one or more workpieces being carried into a first end of the plating tank in the partially immersed state and a current of the current gradual decrease control flows through the one or more workpieces being carried out of a second end of the plating tank in the partially immersed state; and

wherein a current value supplied per unit area of the one or more workpieces is substantially constant while being carried from the first end to the second end of the plating tank including in the partially immersed period when the workpiece is carried into the plating tank and the partially immersed period when the workpiece is carried out of the plating tank.

2. The continuous plating apparatus as defined in claim 1 , further comprising:

a plurality of workpiece carriers that are secured on a transfer rail that extends in the workpiece transfer direction so that the one or more workpieces can be transferred by the workpiece carriers; and

a plurality of arm members, a base of each of the arm members being secured on a corresponding workpiece carrier among the workpiece carriers, and an end of each of the arm members engaging a corresponding cathode relay member among the plurality of cathode relay members so as to allow relative movement,

wherein each of the arm members is formed to allow at least one of a direct and indirect current supply;

wherein power can be supplied to each of the one or more workpieces transferred in the plating tank from a corresponding power supply unit among the plurality of power supply units through a corresponding cathode relay member among the plurality of cathode relay members and a corresponding arm member among the arm members.

3. The continuous plating apparatus as defined in claim 1 , further comprising:

a sensor that identifies the workpiece; and

a memory that stores the length corresponding to the workpiece identified by the sensor,

wherein the period calculation portion calculates the partially immersed period based on the length being read from the memory and the constant transferring speed.

4. The continuously plating apparatus as defined in claim 1 , wherein the current increases linearly from zero at the beginning of the partially immersed period to the constant current Is at the end of the partially immersed period when the workpiece is carried into the plating tank, between the time the workpiece first enters the partially immersed and time L/V.

5. The continuous plating apparatus as defined in claim 4 , wherein the current is linearly decreased from Is at the time where a leading edge of the workpiece is leaving the plating tank.

6. The continuous plating apparatus as defined in claim 1 , wherein the current supplied during the gradual increase and gradual decrease in the partially immersion periods increases and decreases at different rates for workpieces of different lengths.

7. A continuous plating apparatus capable of continuously plating workpieces transferred through a plating tank while continuously supplying power to the workpieces, the continuous plating apparatus comprising:

a computer system coupled to the continuous plating apparatus to control operation of the continuous plating apparatus;

one or more workpieces, a plurality of cathode relay members, a plurality of first-side power supply units and a plurality of second-side power supply units, wherein, when a number of the one or more workpieces simultaneously transferred in the plating tank in a completely immersed state is N in a workpiece transfer direction, (N+1) cathode relay members that extend in the workpiece transfer direction, and (N+1) power supply units are provided outside the plating tank;

a first-side anode and a second-side anode each extending in the workpiece transfer direction, the first-side anode and the second-side anode being oppositely disposed in the plating tank;

a plurality of anode terminals of the first-side power supply units connected to the first-side anode;

a plurality of anode terminals of the second-side power supply units connected to the second-side anode; and

a plurality of cathode terminals of the first-side power supply units and a plurality of cathode terminals of the second-side power supply units connected to the plurality of cathode relay members;

wherein the computer system includes a period calculation portion that calculates a partially immersed period L/V based on a length L of the workpiece being extended in the workpiece transfer direction and a constant transferring speed V of the workpiece in the workpiece transfer direction,

wherein power is supplied to each of the one or more workpieces transferred in the plating tank from a corresponding first-side power supply unit among the first-side power supply units and from a corresponding second-side power supply unit among the second-side power supply units through a corresponding cathode relay member among the plurality of cathode relay members,

wherein each of the first-side power supply units and each of the second-side power supply units controls a current to be supplied to the workpiece under constant current control at a constant current Is when being transferred in the plating tank in a completely immersed state, under current gradual increase control to vary from zero to the constant current Is in the partially immersed period when the workpiece is carried into the plating tank in a partially immersed state, and under current gradual decrease control to vary from the constant current Is to zero in the partially immersed period when the workpiece is carried out from the plating tank in a partially immersed state;

wherein a current of the current gradual increase control flows through the one or more workpieces being carried into a first end of the plating tank in the partially immersed state and a current of the current gradual decrease control flows through the one or more workpieces being carried out of a second end of the plating tank in the partially immersed state; and

wherein a current value supplied per unit area of the one or more workpieces is constant while being carried from the first end to the second end of the plating tank including in the partially immersed period when the workpiece is carried into the plating tank and in the partially immersed period when the workpiece is carried out of the plating tank.

8. The continuous plating apparatus as defined in claim 7 , further comprising:

a plurality of workpiece carriers that are secured on a transfer rail that extends in the workpiece transfer direction so that the one or more workpieces can be transferred by the workpiece carriers; and

a plurality of arm members, a base of each of the arm members being secured on a corresponding workpiece carrier among the workpiece carriers, and an end of each of the arm members engaging a corresponding cathode relay member among the plurality of cathode relay members so as to allow relative movement,

wherein each of the arm members is formed to allow at least one of a direct and indirect current supply;

wherein power can be supplied to each of the one or more workpieces transferred in the plating tank from a corresponding power supply unit among the plurality of first-side power supply units and the second-side power supply through a corresponding cathode relay member among the plurality of cathode relay members and a corresponding arm member among the arm members.

9. The continuous plating apparatus as defined in claim 7 , further comprising:

a sensor that identifies the workpiece; and

a memory that stores the length corresponding to the workpiece identified by the sensor,

wherein the period calculation portion calculates the partially immersed period based on the length being read from the memory and the constant transferring speed.

10. The continuously plating apparatus as defined in claim 7 , wherein the current increases linearly from zero at the beginning of the partially immersed period to the constant current Is at the end of the partially immersed period when the workpiece is carried into the plating tank, between the time the workpiece first enters the partially immersed period and time L/V.

11. The continuous plating apparatus as defined in claim 10 , wherein the current is linearly decreased from Is at the time where a leading edge of the workpiece is leaving the plating tank.

12. The continuous plating apparatus as defined in claim 7 , wherein the current supplied during the gradual increase and gradual decrease in the partially immersed periods increases and decreases at different rates for workpieces of different lengths.