JP2644146B2 - Arc discharge diagnosis method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in arc ion plating for forming a hard film on a tool or a machine part, and is used for normal or normal arc discharge for ionizing a cathode material.
Relates arcing diagnostic method and apparatus you determine the abnormality.

[0002]

2. Description of the Related Art First, an arc ion plating apparatus will be described with reference to FIG. FIG. 4 is a vertical sectional view of the arc ion plating apparatus. In FIG. 4, an arc discharge unit including an anode 3, a cathode material 4 and a striker 6 is provided on the upper surface and side surfaces of the vacuum chamber 2, and a rotary table 7 on which an object to be coated 8 is placed is provided in the center. A supply port 2a and a discharge port 2b for the process gas 9 are provided on a side surface opposite to the arc discharge unit. The anode 3 and the cathode material 4 are connected to an arc power supply unit 5,
The striker 6 is connected to the anode 3 via a resistor 15. The turntable 7 is connected to a bias power supply 14,
As a result, it is maintained at a negative potential together with the object 8 to be coated. Arc ion plating is performed as follows. That is, the striker 6 swings and repeats contact and detachment with the cathode material 4. Discharge occurs in this portion due to contact / separation of the striker 6 with the cathode material 4 (ignition), and this discharge initiates an overall arc discharge between the anode 3 and the cathode material 4. The cathode material 4 is locally evaporated and ionized instantaneously by the energy of the arc discharge, and the vaporized ionized cathode material 10 is deposited on the surface of the object 8 to be coated together with the process gas nitrogen 9 to form a hard film. Things.

By the way, the striker 6 repeats contact and detachment with the cathode material 4 at the time of start, but may be welded while being in contact with the cathode material 4. When striker welding occurs, current continues to flow only through the resistor 15, causing abnormal overheating of the resistor 15. Further, an arc discharge may be generated between portions other than the cathode material 4 (called a short circuit or an abnormal discharge), and there is a possibility that the arc ion plating apparatus 1 and the object to be coated 8 may be fatally damaged.

[0004]

When any of the above-mentioned troubles occurs, normal discharge will not be achieved in any case, and it will be known soon. However, it is necessary to detect the trouble early to stop the arc discharge and perform maintenance. However, conventionally, since the state of the arc discharge has been determined based on the intuition and experience of the operator, it is difficult to detect the occurrence of the trouble early or reliably. Was.

The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to automatically determine a state of an arc discharge to prevent a striker welding and a short circuit. It is an object of the present invention to provide a method and an apparatus for diagnosing arc discharge in an arc ion plating apparatus capable of reliably detecting occurrence at an early stage.

[0006]

An arc discharge diagnostic method for solving the above-mentioned problem is to apply a voltage between an anode and a cathode material in a vacuum to cause a striker to contact / separate from the cathode material and to fire. An arc discharge is generated and this arc discharge
When performing ion arc plating by ionizing the cathode material with electricity, the state of arc discharge is determined by comparing the measured values of the arc voltage and arc current with the set values. In this discrimination mode,
A mode in which it is determined that striker welding has occurred when the measured value of the arc voltage is within the range from the set voltage lower limit to the set voltage upper limit and the measured value of the arc current is equal to or less than the set current lower limit; and / or There is a mode in which it is determined that a short circuit has occurred when the measured value of the arc voltage is equal to or less than the set voltage lower limit value and the measured value of the arc current is equal to or greater than the set current lower limit value. Then, the arc discharge diagnostic apparatus generates an arc discharge by applying a voltage between the anode and the cathode material by the arc power supply unit in a vacuum, causing the striker to come into contact with and detach from the cathode material, and igniting the arc. By discharge
An arc discharge diagnostic apparatus used when performing ion arc plating by ionizing the cathode material, wherein a state of the arc discharge is determined by comparing a measured value and a set value of the input arc voltage and arc current. a comparing unit for outputting a signal when it is determined that trouble has occurred while, the contact output units to be sent to the message display unit a signal from the comparison operation unit displays the occurrence of the arc power supply unit, and trouble Yes
The comparison operation unit sets the measured value of the arc voltage.
Within the range from the voltage lower limit to the set voltage upper limit and
When the measured value of the arc current is below the set current lower limit
And / or output a striker welding signal, and / or
The measured value of the arc voltage is less than the set voltage lower limit and the arc
If the measured current is greater than or equal to the set current lower limit,
It outputs a signal .

[0007]

According to the present invention, the cathode material is formed by arc discharge.
Troubles striker welding and short circuit or the like that occurs when performing arc ion plating by ionized,
It was completed by obtaining the knowledge that there is a correlation with the arc voltage value and the arc current value. That is, in the normal discharge, the voltage - there current characteristic almost constant range, voltage and current set lower limit value of voltage V _L, set the voltage upper limit value V _H, within a predetermined range which is defined by the set current limit value I _L It is in. However, when a trouble occurs, it will be out of this fixed range,
The state of the arc discharge is determined by comparing the measured values of the arc voltage and the arc current with these set values.
Specifically, at the time of striker welding, the arc current decreases even if the arc voltage is normal. At the time of a short circuit, the arc voltage decreases even if the arc current is normal. In the arc discharge diagnosis device, the comparison operation unit compares the measured values of the input arc voltage and arc current with the set values to determine the state of the arc discharge and to signal when a trouble has occurred. And the contact output unit sends a signal from the comparison operation unit to the arc power supply unit and a message display unit that indicates the occurrence of a trouble, so that when a trouble occurs, the power is turned off and a message to that effect is displayed. .

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram of the arc discharge diagnostic apparatus of the present invention, FIG. 2 is a flowchart of a program incorporated in the comparison operation unit of FIG. 1, and FIG. 3 shows each trouble mode classified by arc voltage and arc current. FIG. In FIG. 1, portions having the same functions as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

First, the configuration will be described with reference to FIG. FIG.
In the figure, reference numeral 25 denotes an arc power supply unit controlled by a constant current. The arc power supply unit 5 in FIG. 4 is provided with an arc voltage signal output terminal 27 and an arc current signal output terminal 28. Reference numeral 26 denotes an arc discharge diagnosis device, which includes a comparison operation unit (CPU) 24, an A / D converter 23, a contact output unit 22, and the like. The measured values of the arc voltage and the arc current, that is, the arc voltage signal and the arc current signal of the arc power supply unit 25 are input to the A / D converter 23,
The signal is converted into a digital signal and input to a comparison operation unit 24 which is a microcomputer. The comparison operation unit 24 determines the state of the arc discharge by comparing the input measured values of the arc voltage value and the arc current value with the set values in accordance with the incorporated program, and determines a trouble such as a striker welding or a short circuit. If it is determined that a signal has occurred, a signal is output to the contact output unit 22. The contact output unit 22 converts the digital signal from the comparison operation unit 24 into a power ON / OFF signal or a message display signal and sends it to the arc power supply unit 25 or the message display unit 29.

Next, the operation will be described with reference to FIG. In FIG. 2, when the arc ion plating apparatus is turned on, the arc voltage V and the arc current I are measured (Step # 1). Arc current I is compared whether the following set current limit value I _L (step # 2), proceeds to the arc voltage V is compared whether the following set voltage limit value V _L when YES is determined in step # 3 You. Power off if determined to be YES
State signal is outputted (step # 4), transition arc voltage V is compared whether the setting voltage upper limit value V _H above step # 5 when it is determined that the NO. If determined as YES, a no-load state signal is output (step # 6), and if determined as NO, a striker welding signal is output (step # 6).
7), an arc power OFF signal and a message display signal are output (steps # 8 and 9). If NO is determined in step # 2, the process proceeds to step # 10 where it is compared whether the arc voltage V is equal to or lower than the set voltage lower limit value _VL . Y
If it is determined as ES, a short-circuit signal is output (step # 1).
1) An arc power OFF signal and a message display signal are output (steps # 8 and # 9). If NO is determined, a normal discharge signal is output (step # 12). Steps # 4, 6, 9, and 12 are followed by step #
Return to 1.

[0011] Here will be described on the basis of the set lower limit value of voltage V _L, set the voltage upper limit value V _H, and a method for determining the set current limit value I _L in FIG. FIG. 3 is a diagram showing each trouble mode classified by an arc voltage and an arc current. V _L and V _H are respectively a lower limit and an upper limit value of the voltage in the case of normal discharge, which is the lower limit of the current in the case of I _L normal discharge. Since the voltage-current characteristics of arc discharge show almost constant voltage characteristics in the usage range, in the case of a constant current power supply, the current value is determined by the set current value with the current capacity of the power supply as the upper limit, and the voltage is set with the voltage capacity as the upper limit. Determined by distance.
Therefore, the voltage and current in the case of normal discharge are set voltage lower limit value _VL and set voltage upper limit value _VL determined according to the use condition.
_H, and a range partitioned by the set current limit value I _L 32
Value within. When a short circuit occurs, the current value is the same as in the case of normal discharge, but the voltage value decreases because the discharge distance is short. Therefore, setting the lower limit value of voltage V _L the range 31 is a region indicating a short-circuit current can be set lower limit value I _L or more. When striker welding occurs, the voltage value is the same as in normal discharge, but the arc discharge does not start and the current determined by the resistance value of the resistor connected in series with the striker flows, and the current value is normal discharge. It becomes smaller than the case of.
Therefore, the set voltage lower limit value V _L or more, the set voltage upper limit value V _H
Or less and set the current limit value I _L the range 34 is a region showing the striker welding. Note that when no current flows and only voltage rises, the state is a no-load state, and when no current flows and no voltage rises, the power supply is off. Accordingly, the ranges of 33 and 35 are regions indicating the power-off state and the no-load state, respectively. In this way, the trouble mode can be classified according to the values of the arc voltage and the arc current.

Therefore, in the arc ion plating apparatus, it is possible to automatically determine whether the striker is welded or short-circuited by using the above-described method and apparatus for diagnosing arc discharge. Further, the arc power can be turned off early by using the discrimination signal, and a message can be issued to the operation panel or the like. Thereby, in the case of striker welding, abnormal overheating of the resistor can be prevented, and in the case of short circuit, damage due to discharge of a portion other than the evaporation surface of the cathode material can be minimized.

[0013]

According to the method and apparatus for diagnosing arc discharge of the present invention, whether arc discharge is normal or not is determined by comparing the measured values of arc voltage and arc current with the set values.
In order to determine the state of the abnormality, it is possible to find the trouble early and reliably without relying on the intuition and experience of the operator. Also, depending on the direction in which the arc voltage and the arc current deviate from a certain range, striker welding or / and / or
And the details of troubles such as short circuits can be distinguished, and detailed diagnosis can be made. According to the arc discharge diagnostic apparatus of the present invention, when a trouble occurs, the power of the arc power supply unit is automatically turned off, and the content of the trouble is displayed on the message display unit. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an arc discharge diagnostic device of the present invention.

FIG. 2 is a flowchart of a program incorporated in a comparison operation unit in FIG. 1;

FIG. 3 is a diagram showing each trouble mode divided by an arc voltage and an arc current.

FIG. 4 is a longitudinal sectional view of the arc ion plating apparatus.

[Explanation of symbols]

I arc current _IL current lower limit value V arc voltage _VH voltage upper limit value _VL lower voltage limit value 1 arc ion plating device 2 vacuum chamber 3 anode 4 cathode material 6 striker 24 comparison operation unit 26 arc discharge diagnosis device 27 arc voltage signal Output terminal 28 Arc current signal output terminal 29 Message display unit

Claims (6)

(57) [Claims] An arc discharge is generated by applying a voltage between an anode material and a cathode material in a vacuum to cause a striker to contact and detach from the cathode material and to fire the arc.
Therefore, when performing ion ion plating by ionizing the cathode material, the measured values of the arc voltage and arc current are compared with the set values.
And, setting a measured value is set lower limit value of voltage of the arc voltage voltage
The measured value of the arc current is set within the range up to the upper limit.
When the current is below the lower limit of the constant current, striker welding occurs
An arc discharge diagnosis method , wherein the state of the arc discharge is determined by determining that the arc discharge has occurred . 2. A voltage is applied between the anode and cathode materials in a vacuum.
Ignition by applying / disconnecting the striker to / from the cathode material
This causes an arc discharge, and this arc discharge
Therefore, the cathode material is ionized to form an arc ion plate.
In performing computing, comparing the measured value of the arc voltage and arc current with the set value
And the measured value of the arc voltage is equal to or less than the set voltage lower limit and
When the measured value of the arc current is greater than or equal to the set current lower limit
And determining the state of the arc discharge by determining that a short circuit has occurred .
Discharge diagnosis method. 3. A voltage is applied between the anode and cathode materials in a vacuum.
Ignition by applying / disconnecting the striker to / from the cathode material
This causes an arc discharge, and this arc discharge
Therefore, the cathode material is ionized to form an arc ion plate.
In performing computing, comparing the measured value of the arc voltage and arc current with the set value
And, setting a measured value is set lower limit value of voltage of the arc voltage voltage
The measured value of the arc current is set within the range up to the upper limit.
When the current is below the lower limit of the constant current, striker welding occurs
And the measured value of the arc voltage is less than or equal to the set voltage lower limit and
When the measured value of the arc current is greater than or equal to the set current lower limit
And determining the state of the arc discharge by determining that a short circuit has occurred .
Discharge diagnosis method. Wherein to generate an arc discharge by firing by contacting and separating the striker to the cathode material by applying a voltage between the anode and the cathode material by the arc power supply unit in vacuo, the by the arc discharge Ion cathode material
This is an arc discharge diagnostic device used when performing arc ion plating and comparing the input measured values of the arc voltage and arc current with the set values to determine the state of arc discharge and cause trouble. a and a comparing unit for outputting a signal when it is determined that, the contact output unit for sending a signal from the comparing unit in the message display unit for displaying the occurrence of the arc power supply unit and trouble, the comparison operation The section indicates that the measured value of the arc voltage is the set voltage.
Within the range from the lower limit to the set voltage upper limit,
When the measured current is below the set current lower limit,
An arc discharge diagnostic device that outputs a trimmer welding signal . 5. An anode powered by an arc power supply unit in a vacuum.
Voltage between the cathode material and the striker
Arc discharge is generated by contacting and detaching
The cathode material is ionized by the arc discharge.
Used for arc ion plating
And a set value of an input arc voltage and an arc current.
The state of arc discharge by comparing
Outputs a signal when it is determined that a trouble has occurred
And a signal from the comparison operation unit, the arc power supply unit and
Send a message to the message display unit
A contact output unit for outputting the measured value of the arc voltage.
The measured value of the arc current is below the lower limit and the measured current is below the set current.
Arc discharge that outputs a short-circuit signal when it is equal to or greater than the limit value
Diagnostic device. 6. An anode powered by an arc power supply unit in a vacuum.
Voltage between the cathode material and the striker
Arc discharge is generated by contacting and detaching
The cathode material is ionized by the arc discharge.
Used for arc ion plating
And a set value of an input arc voltage and an arc current.
The state of arc discharge by comparing
Outputs a signal when it is determined that a trouble has occurred
And a signal from the comparison operation unit, the arc power supply unit and
Send a message to the message display unit
A contact output unit for outputting the measured value of the arc voltage.
Within the range from the lower limit to the set voltage upper limit,
When the measured current is below the set current lower limit,
A trimmer welding signal is output, and the measured value of the arc voltage is
When the measured value of the arc current is equal to or less than the
Output short-circuit signal when the current is lower than the lower limit of constant current.
Discharge diagnostic device.