JP6418103B2 - Electrostatic coating apparatus and its conductivity inspection method - Google Patents

Description

  The present invention relates to an electrostatic coating apparatus and a conductivity inspection method thereof, for example, an electrostatic coating apparatus capable of confirming the conductivity of an object to be coated and a conductivity inspection method thereof.

  One of the methods for painting an object is electrostatic painting. In this electrostatic coating, a high voltage is applied to a coating gun or the like to generate an electric field between the coating gun and the object to be coated. In electrostatic coating, a coating material is applied by spraying a coating material charged with a high voltage from the coating gun onto the coating material. At this time, when the object to be coated is a part having low conductivity such as a resin part, a conductive primer is applied to the surface to be coated, and electrostatic coating is performed after ensuring the conductivity. Thus, when applying a conductive primer to a to-be-coated object beforehand, it is necessary to confirm that electroconductivity is ensured after apply | coating a conductive primer. This conductivity is confirmed by confirming whether or not the object to be coated is grounded. An example of a technique for confirming the ground state of an object to be coated is disclosed in Patent Document 1.

  An electrostatic coating apparatus described in Patent Document 1 generates a coating gun for spraying paint on an object to be coated, a robot arm that supports the coating gun so as to be displaceable, a high voltage applied to the coating gun, A high voltage generator for adjusting a high voltage to be generated by detecting a discharge current generated between the gun and the object to be coated. And in the electrostatic coating apparatus of patent document 1, in the state which has not sprayed the coating material toward the to-be-coated object with the coating gun, an electric field is formed toward the to-be-coated object, and this to-be-coated object In the state where the high voltage generator is not applying a high voltage to the coating gun, the electric charge charged to the coating object is used to detect the discharge current generated between the coating gun and the coating object. To do.

JP 2012-071224 A

  However, when a conductive object to be coated is disposed in proximity, the current flowing from the electrostatic coating apparatus to the first object to be subjected to conductivity inspection is disposed in proximity to the first object. It may leak to the second object side. This current leakage phenomenon will be described with reference to FIG.

  FIG. 9 is a schematic view of an electrostatic coating apparatus for explaining the problem. In the schematic diagram shown in FIG. 9, the first article 110a and the second article 110b are grounded to ground through another path. Then, in order to perform the conductivity inspection, an electrostatic coating apparatus (for example, a coating gun 120a) sprays the spray paint 121a onto the first object 110a. At this time, in the example shown in FIG. 9, the bell side leakage current i1L flows through the second article 110b.

  When such a bell side leakage current is generated, a problem occurs in that the current measured as the ground side current i2a decreases and the measurement accuracy decreases.

  This invention is made | formed in view of the said situation, and aims at improving the precision of the electroconductivity test | inspection in a coating process.

  One aspect of the electrostatic coating apparatus according to the present invention is provided with at least one coating object for a plurality of objects to be coated, and sprays a paint toward the object to be coated, and the plurality of objects from the coating gun. A bell-side current calculation unit for calculating a bell-side total current that is a total value of bell-side currents flowing through the coating material, and a ground-side total current that is a total value of earth-side currents flowing from the plurality of coating objects to the ground A ground-side current measuring unit, the bell-side total current and the ground-side total current measured during electrostatic coating, and the bell-side total current and the ground-side total current when the ground is correctly connected, An earth inspection unit for detecting an abnormal state of the ground state of the plurality of objects to be coated according to the magnitude relationship.

  In the electrostatic coating apparatus according to the present invention, a plurality of objects to be coated are connected to a common ground, a ground-side total current flowing through the commonly connected ground, a bell-side total current flowing through the plurality of objects to be coated, And the influence of the bell side leakage current can be reduced by conducting the conductivity test based on the measured value, and the accuracy of the conductivity test can be improved.

  The ground inspection unit according to the present invention includes a ratio of the bell side total current and the ground side total current measured during electrostatic coating, the bell side total current and the ground side total current in a state where the ground is correctly connected. An abnormal state of the ground state of the plurality of objects to be coated is detected based on a difference between the ratio to the current and a reference value set based on the ratio.

  The ground inspection unit according to the present invention reduces the number of reference values for determining the presence or absence of ground by inspecting the ground state based on the ratio of the bell total current and the ground-side total current, and the variation of the measurement system. The inspection accuracy can be increased by reducing the influence.

  An electrostatic coating apparatus according to the present invention includes a plurality of ground electrodes that support the plurality of objects to be coated, connect the plurality of objects to be grounded, and support the plurality of objects to be coated. An object fixing jig is further provided, and the plurality of ground electrodes are electrically connected.

  The electrostatic coating apparatus according to the present invention can measure the total earth-side current flowing from a plurality of objects to be grounded by one earth-side current measuring unit by electrically connecting a plurality of earth electrodes. it can.

  One aspect of the conductivity inspection method according to the present invention is provided with at least one coating gun for spraying a plurality of objects to be coated, and spraying a paint toward the object to be coated. A bell-side current calculation unit for calculating a bell-side total current that is a total value of bell-side currents flowing through the coating material, and a ground-side total current that is a total value of earth-side currents flowing from the plurality of coating objects to the ground A ground-side current measuring unit, and a conductivity inspection method in the electrostatic coating apparatus, wherein the bell-side total current and the ground-side total current at the time of electrostatic coating are calculated as measured values, and the calculated An abnormal state of the ground state of the plurality of objects to be coated is detected according to the magnitude relationship between the bell side total current and the ground side total current in a state where the measured value and the ground are correctly connected.

  In the conductivity inspection method according to the present invention, a plurality of objects to be coated are connected to a common ground, a ground-side total current flowing through the commonly connected ground, a bell-side total current flowing through the plurality of objects to be coated, And the influence of the bell side leakage current can be reduced by conducting the conductivity test based on the measured value, and the accuracy of the conductivity test can be improved.

  The conductivity inspection method according to the present invention includes a ratio of the bell-side total current and the earth-side total current measured during electrostatic coating, and the bell-side total current and the ground-side in a state where the ground is correctly connected. An abnormal state of the ground state of the plurality of objects to be coated is detected based on a difference from a reference value set based on a ratio with the total current.

  The conductivity inspection method according to the present invention reduces the number of reference values for determining the presence or absence of ground by inspecting the ground state based on the ratio of the bell total current and the ground side total current, and also varies the measurement system. The inspection accuracy can be increased by reducing the influence of the above.

  The conductivity inspection method according to the present invention is performed in at least one of a primer coating process, a base coating process, and a clear coating process.

  The conductivity inspection method according to the present invention, when the coating process is constructed in a plurality of steps, can conduct the conductivity inspection in any step, increasing the degree of freedom of the process construction method, and Reliability of the entire process can be improved.

  According to the electrostatic coating apparatus according to the present invention, it is possible to improve the accuracy of the conductivity inspection for the object to be coated.

1 is a schematic diagram of an electrostatic coating apparatus according to a first embodiment. 1 is a block diagram of a bell coating machine and a high voltage applying device according to a first embodiment. 3 is a flowchart for explaining the operation of the electrostatic coating apparatus according to the first exemplary embodiment. 6 is a table for explaining a difference between a bell-side current and a ground-side current depending on presence / absence of ground in the electrostatic coating apparatus according to the first exemplary embodiment. 6 is a graph illustrating a first example for explaining the correlation between the bell-side total current and the ground-side total current in the electrostatic coating apparatus according to the first exemplary embodiment; It is a graph which shows the 2nd example explaining the correlation of the bell side total current in the electrostatic coating apparatus concerning Embodiment 1, and a ground side total current. It is the schematic of the electrostatic coating apparatus concerning Embodiment 2. FIG. It is a flowchart explaining the coating process using the electrostatic coating apparatus concerning Embodiment 1,2. It is the schematic of the electrostatic coating apparatus for demonstrating a subject.

  Embodiments of the present invention will be described below with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary.

  FIG. 1 shows a schematic diagram of an electrostatic coating apparatus 1 according to the first embodiment. The electrostatic coating apparatus 1 is an apparatus that performs coating on the first object 10a and the second object 10b using the coating guns 20a and 20b. As shown in FIG. 1, the electrostatic coating apparatus 1 includes a workpiece fixing jig 11, an insulator 12, a pedestal portion 13, ground electrodes 14 a and 14 b, a ground-side current measuring unit (for example, an ammeter 15), a coating Guns 20a and 20b, high voltage application devices 22a and 22b, and a ground inspection unit 23 are provided.

  Although FIG. 1 shows an example in which two coating guns are provided for two objects to be coated, an example in which one painting gun is provided for a plurality of objects to be coated is also conceivable. In this case, the electrostatic coating apparatus 1 according to the first embodiment coats a plurality of objects to be coated with one painting gun.

  The object fixing jig 11 fixes the first object 10a and the second object 10b. The article fixing jig 11 is fixed to the pedestal portion 13 via the insulator 12. The insulator 12 insulates the article fixing jig 11 and the pedestal portion 13. The pedestal portion 13 is electrically grounded. Further, the article fixing jig 11 includes ground electrodes 14a and 14b connected through conductive wiring. The ground electrode 14a is connected to the first article 10a to connect the first article 10a to the ground. The ground electrode 14b is connected to the second article 10b and is used to connect the second article 10b to the ground. The article fixing jig 11 according to the first embodiment is formed of a conductive member. The ground electrode 14 a and the ground electrode 14 b are electrically connected by the article fixing jig 11. The ground electrodes 14 a and 14 b are grounded via the ammeter 15. The article fixing jig 11 is also grounded via an ammeter 15. Both the earth-side current flowing through the first object 10a and the earth-side current flowing through the second object 10b flow into the ammeter 15. Therefore, the ammeter 15 measures the ground-side total current i2 that is the total value of the ground-side current flowing through the first article 10a and the earth-side current flowing through the second article 10b. .

  The coating guns 20a and 20b spray spray paints 21a and 21b. A high voltage is applied to the coating gun 20a from the high voltage applying device 22a. A high voltage is applied to the coating gun 20b from the high voltage applying device 22b. The coating guns 20a and 20b generate electric fields between the coating gun 20a and the first article 10a and between the painting gun 20b and the second article 10b by this high voltage and apply the paint. Charge. The high voltage application device 22a generates a high voltage to be applied to the coating gun 20a and calculates a bell-side current i1a flowing from the coating gun 20a to the first article 10a to be coated. The high voltage application device 22b generates a high voltage to be applied to the coating gun 20b, and calculates a bell-side current i1b flowing from the coating gun 20b to the second object to be coated 10b.

  The ground inspection unit 23 detects an abnormality in the ground state of the first article 10a and the second article 10b based on the bell-side currents i1a and i1b and the ground-side total current i2. More specifically, the ground inspection unit 23 performs the bell-side total current and the ground-side total current, which are the total values of the bell-side currents i1a and i1b measured during electrostatic coating, and the bell in a state where the ground is correctly connected. The abnormal state of the ground state of a plurality of objects to be coated is detected according to the magnitude relationship between the side total current and the ground side total current. In the present embodiment, when the ground inspection unit 23 determines that the ground state of the first article 10a and the second article 10b is abnormal, the high-voltage applying devices 22a and 22b have a high voltage. The control signal CNT that stops generation is enabled. Details of the conductivity inspection method for the first object 10a and the second object 10b in the earth inspection unit 23 will be described later.

  Here, the coating guns 20a and 20b and the high voltage application devices 22a and 22b will be described in more detail. Since the coating guns 20a and 20b are devices having substantially the same configuration, 20 is used as a coating gun symbol in the following description. Further, since the high voltage applying devices 22a and 22b are devices having substantially the same configuration, 22 is used as a reference numeral of the high voltage applying device in the following description. FIG. 2 shows a block diagram of the bell coating machine and the high voltage applying device according to the first embodiment. As shown in FIG. 2, the painting gun 20 is a part of the bell painting machine 30. Further, the high voltage application device 22 includes a high voltage generator 31 and a high voltage controller 40 in the bell coating machine 30. The bell coating machine 30 and the high voltage controller 40 are connected by, for example, a 6-core to 8-core cable CAB.

  The bell coating machine 30 is obtained by adding a high voltage generator 31 to the coating gun 20. Further, the bell coating machine 30 is provided with a leak current detection unit 36. The high voltage generator 31 includes a booster circuit 32, high voltage measurement resistors 33a and 33b, a total current measurement resistor 34, and a leak current measurement resistor 35. The input voltage supplied from the booster circuit 32 and the high voltage controller 40 is boosted by a drive pulse to generate a high voltage HV to be applied to the coating gun 20. As the booster circuit 32, for example, a Cockcroft-Walton booster circuit (CW circuit) can be used. Further, in the booster circuit 32, a transformer is provided, and a total current measurement resistor 34 is provided between one end of the secondary side coil of the transformer and a ground wiring to which a ground voltage is supplied. Then, the voltage V 0 is generated at the terminal on the high voltage generator 31 side of the total current measuring resistor 34. The total current IM can be calculated by dividing the voltage V0 by the resistance value of the total current measuring resistor 34.

  A high voltage measuring resistor 33a and a high voltage measuring resistor 33b are connected in series between the output terminal of the high voltage generator 31 and the ground wiring. The voltage V1 at the connection point between the high voltage measuring resistor 33a and the high voltage measuring resistor 33b is a voltage obtained by dividing the high voltage HV output from the high voltage generator 31 by the high voltage measuring resistor 33a and the high voltage measuring resistor 33b. Become. Here, since the high voltage measuring resistor 33a and the high voltage measuring resistor 33b have known resistance values, the voltage value of the high voltage HV can be calculated from the voltage V1. The bleeder current IM1 flows through the high voltage measuring resistor 33a and the high voltage measuring resistor 33b. The bleeder current IM1 can also be calculated by dividing the high voltage HV by the sum of the resistance values of the high voltage measuring resistor 33a and the high voltage measuring resistor 33b.

  Further, in the bell coating machine 30, the rear plate side leakage current IM2 flows along with the dirt on the outer surface of the bell coating machine 30. Therefore, the bell coating machine 30 detects the rear plate side leakage current IM2 by the leakage current detector 36. Specifically, a leakage current measurement resistor 35 is provided between the leakage current detector 36 and the ground wiring. Therefore, the rear plate side leakage current IM2 that has flowed to the leakage current detector 36 flows to the ground wiring via the leakage current measuring resistor 35. As a result, the voltage V <b> 2 is generated on the leakage current detection unit 36 side of the leakage current measuring resistor 35. Therefore, the rear plate side leakage current IM2 can be calculated by dividing the voltage V2 by the resistance value of the leakage current measuring resistor 35.

  The high voltage controller 40 includes a calculation unit 41, a high voltage generation control unit 42, a total current measurement unit 43, a voltage measurement unit 44, and a leak current measurement unit 45. The high voltage generation control unit 42 generates an input voltage and a driving pulse to be given to the high voltage generator 31. The high voltage generation control unit 42 changes the voltage level of the input voltage, the duty ratio of the drive pulse, and the like according to an instruction from the calculation unit 41. The total current measurement unit 43 acquires the voltage V0, calculates the total current IM based on the acquired voltage V0, and outputs the calculated value of the total current IM to the calculation unit 41. The voltage measurement unit 44 measures the voltage V1 and outputs the measured voltage value to the calculation unit 41. The leakage current measuring unit 45 acquires the voltage V2, calculates the rear plate side leakage current IM2 based on the acquired voltage V2, and outputs the calculated value of the rear plate side leakage current IM2 to the calculation unit 41.

  The calculation unit 41 calculates a voltage value of the high voltage HV based on the voltage V1 acquired from the voltage measurement unit 44, and controls the high voltage generation control unit 42 based on the calculated value of the high voltage HV. In addition, the calculation unit 41 has a function of stopping the output of the high voltage HV by stopping the operation of the high voltage generation control unit 42 in accordance with the control signal CNT given from the ground inspection unit 23. Moreover, the calculating part 41 contains a bell side current calculation part. In this bell-side current calculation unit, the total current IM acquired from the total current measurement unit 43, the bleeder current IM1 calculated based on the voltage V1 acquired from the voltage measurement unit 44, and the rear plate acquired from the leak current measurement unit 45 The bell side current i1 is calculated based on the side leakage current IM2. Then, the calculation unit 41 outputs the calculated bell-side current i1 to the ground inspection unit 23.

Here, a method of calculating the bell-side current i1 will be described. The bell side current calculation unit included in the calculation unit 41 calculates the bell side current i1 based on the equation (1).
i1 = IM-IM1-IM2 (1)
In the equation (1), the total current IM and the rear plate side leakage current IM2 are actual measured values. On the other hand, the bleeder current IM1 is a calculated value calculated from the high voltage HV output from the booster circuit 32 and the resistance values of the high voltage measuring resistor 33a and the high voltage measuring resistor 33b.

  In the electrostatic coating apparatus 1 according to the first embodiment, a value obtained by subtracting the bleeder current IM1 from the total current IM is referred to as an output current theoretical value.

  Then, operation | movement of the electrostatic coating apparatus 1 concerning Embodiment 1 is demonstrated. FIG. 3 is a flowchart for explaining the operation of the electrostatic coating apparatus 1 according to the first embodiment. As shown in FIG. 3, the electrostatic coating apparatus 1 according to the first embodiment inspects the conductivity of the article to be coated 10 while performing electrostatic coating.

  The electrostatic coating apparatus 1 calculates the bell-side current i1a when the spray paint 21a charged from the paint gun 20a is sprayed onto the first article 10a, and the spray charged from the paint gun 20b. A bell-side current i1b when the paint 21b is sprayed onto the first article 10b is calculated (step S1). Moreover, the electrostatic coating apparatus 1 detects the earth side total current i2 which flows from the 1st to-be-coated object 10a and the 2nd to-be-coated object 10b to earth | ground during the electrostatic coating with the ammeter 15 (step S2). Then, the electrostatic coating apparatus 1 includes the first object 10a and the second object to be coated based on the bell-side total current i1 and the ground-side total current i2 that are the sum of the bell-side current i1a and the bell-side current i1b. The ground state of the coating material 10b is determined (step S3).

  Here, a method for determining the ground state in the electrostatic coating apparatus 1 will be described. In the electrostatic coating apparatus 1, when the ground of the first article 10a and the second article 10b is correctly grounded (hereinafter referred to as a grounded state), an abnormal state where the ground is not correctly grounded ( In the following, there is a large difference between the bell side total current i1 and the ground side total current i2. FIG. 4 shows a table for comparing the bell-side total current i1 and the ground-side total current i2 with and without the ground. In the example shown in FIG. 4, the current value when the applied voltage to the coating guns 20a and 20b is set to 60 kV is compared between a grounded state and a groundless state. When the ground is present, the total current IM described above is 67.5 μA, the leakage current IM1 is 9.9 μA, the bleeder current IM2 is 30 μA, the bell-side total current i1 calculated by the equation (1) is 27.6 μA, The ground-side total current i2 is 25.0 μA. On the other hand, when there is no ground, the total current IM described above is 53.8 μA, the leakage current IM1 is 10.9 μA, the bleeder current IM2 is 30 μA, and the bell-side total current i1 calculated by the equation (1) is 12. 9 μA, and the ground-side total current i2 is 7.6 μA. That is, the bell-side total current i1 has a difference of two times or more depending on the presence or absence of the ground, and the bell-side total current i2 has a difference of three times or more. Further, even when the ratio of the bell-side total current i1 and the ground-side total current i2 is compared, a difference of 32% occurs depending on whether or not the ground is taken.

  Since a difference in current as shown in FIG. 4 occurs, the ground inspection unit 23 of the electrostatic coating apparatus 1 according to the first embodiment performs grounding by either the first determination method or the second determination method. Judge abnormalities.

  In the first determination method, the bell-side total current i1 and the ground-side total current i2 when the ground is normally taken are respectively set in advance as reference values. In the first determination method, one of the difference between the calculated bell-side total current i1 and the reference value and the difference between the measured ground-side total current i2 and the reference value is equal to or greater than a predetermined threshold. It is determined that a ground fault has occurred in response to

  In the second determination method, a ratio (for example, i2 / i1) between the bell-side total current i1 and the ground-side total current i2 when the ground is normally taken is set in advance as a reference value. In the second determination method, the ground abnormality is detected in accordance with the difference between the ratio of the calculated bell-side total current i1 and the measured ground-side total current i2 and the reference value being equal to or greater than a predetermined threshold value. Is determined to have occurred.

  As shown in FIG. 3, the electrostatic coating apparatus 1 according to the first embodiment detects an abnormality in the ground state of the first article 10 a and the second article 10 b based on the determination method. In this case, the control signal CNT output from the ground inspection unit 23 is enabled and the electrostatic coating is interrupted (NO branch of step S4). On the other hand, in the electrostatic coating apparatus 1 according to the first embodiment, when it is determined that there is no abnormality in the ground state of the article to be coated 10 based on the above determination method (YES branch of step S4), the electrostatic coating is continued. (Step S5), electrostatic coating is completed.

  Here, in the electrostatic coating apparatus 1 according to the first embodiment, it is possible to suppress the influence of the leakage bell current generated between the plurality of objects to be coated. Therefore, the correlation between the bell-side current and the ground-side current when two objects to be coated are arranged close to each other will be described.

  FIG. 5 shows a graph illustrating a first example for explaining the correlation between the bell-side total current and the ground-side total current in the electrostatic coating apparatus according to the first exemplary embodiment. This first example shows the relationship between the bell-side total current and the ground-side total current when two coating objects are coated using one coating gun. As shown in FIG. 5, in the first example, a bell-side total current that is the sum of bell-side currents flowing from one paint gun to the first article 10a and the second article 10b, There is a high correlation between the ground-side total current flowing to the ground via the first object 10a and the second object 10b.

  Moreover, the graph which shows the 2nd example explaining the correlation of the bell side total current and the earth side total current in the electrostatic coating apparatus concerning Embodiment 1 in FIG. 6 is shown. This second example shows the relationship between the bell-side total current and the ground-side total current when two coating guns are used for coating two objects. As shown in FIG. 6, also in the second example, the bell-side total current that is the sum of the bell-side currents flowing from the paint gun to the first article 10a and the second article 10b, There is a high correlation between the ground-side total current flowing to the ground via the article 10a and the second article 10b.

  From the above description, according to the electrostatic coating apparatus 1 according to the first embodiment, based on the bell-side total current i1 and the ground-side total current that is the total value of the currents flowing from the plurality of objects to be grounded. Conduct conductivity inspection. As a result, the electrostatic coating apparatus 1 according to the first embodiment can perform the electrical conductivity inspection with high accuracy without being affected by the bell current leaking to the object to be coated on the side not subjected to the electrical conductivity inspection. .

  Moreover, since it is not influenced by the bell current which leaks to the to-be-coated object which is not the object of an electrical conductivity test | inspection, in the coating process using the electrostatic coating apparatus 1 concerning Embodiment 1, a plurality of to-be-coated objects Can be placed in close proximity. Furthermore, in the coating process using the electrostatic coating apparatus 1 according to the first embodiment, even when a plurality of objects are coated with one coating gun, the object of conductivity inspection is performed from one coating gun. Even when a part of the bell current flows as a leakage current with respect to an object to be coated, the measurement accuracy can be kept high. That is, in the coating process using the electrostatic coating apparatus 1 according to the first embodiment, the work space can be reduced while increasing the accuracy of the conductivity inspection.

  The ground inspection unit 23 according to the first embodiment checks the ground state based on the ratio of the bell total current and the ground side total current, thereby reducing the number of reference values for determining the presence or absence of the ground and measuring system. Inspection accuracy can be increased by reducing the influence of fluctuations.

Embodiment 2
In the first embodiment, the example using the object fixing jig 11 that supports a plurality of objects to be coated and is formed of a conductor member has been described. Embodiment 2 demonstrates the example which has the to-be-coated object fixing jigs 11a and 11b for every to-be-coated object. FIG. 7 shows a schematic diagram of the electrostatic coating apparatus 2 according to the second embodiment.

  As shown in FIG. 7, in the electrostatic coating apparatus 2 according to the second embodiment, a jig (for example, a jig that supports the first object 10a and electrically connects the first object 10a to the ground (for example, The workpiece fixing jig 11a, the insulator 12a, the pedestal portion 13a, and the ground electrode 14a) and the second workpiece 10b are supported, and the second workpiece 10b is electrically connected to the ground. Tools (for example, an object fixing jig 11b, an insulator 12b, a pedestal portion 13b, and a ground electrode 14b) are provided independently of each other. In the electrostatic coating apparatus 2 according to the second embodiment, the workpiece fixing jig 11a and the workpiece fixing jig 11b are electrically connected by the ground connection wiring 50. Thereby, in the electrostatic coating apparatus 2 according to the second embodiment, a plurality of ground electrodes are electrically connected and connected to a common ground. The ammeter 15 is provided on a wiring that connects the ground electrodes 14a and 14b together.

  From the above description, in the electrostatic coating apparatus 2 according to the second embodiment, a plurality of object fixing jigs are connected to the ground connection wiring even when the object fixing jigs are independent for each object to be coated. By connecting at 50, the earth side total current which is the total value of the earth side currents flowing through the plurality of objects to be coated is measured by one ammeter 15. Thereby, also in the electrostatic coating apparatus 2 concerning Embodiment 2, the precision of an electroconductivity test | inspection can be raised similarly to the electrostatic coating apparatus 1 concerning Embodiment 1. FIG.

Embodiment 3
In the third embodiment, a coating process using the electrostatic coating apparatus described in the first and second embodiments will be described. FIG. 8 is a flowchart for explaining a coating process using the electrostatic coating apparatus according to the first and second embodiments.

  As shown in FIG. 8, in the coating process according to the third embodiment, a primer coating process is performed (step S11). In this primer coating process, the conductive primer is electrostatically coated. Then, in the primer coating process according to the third embodiment, the primer is coated while conducting the conductivity test, and the completion of the primer coating is determined according to the sufficient conductivity (step S12). .

  Next, the process proceeds to the base coating process (step S14) through the preheating process (step S13) of the object to be coated. In the base coating process of step S14, the base paint is electrostatically coated. Further, in the base coating process in step S14, the conductivity inspection is performed simultaneously with the coating of the base paint.

  Next, the process proceeds to the clear coating process (step S16) through the preheating process (step S15) of the article to be coated. In the clear coating process of step S16, the clear paint is electrostatically applied. Further, in the clear coating process in step S16, the conductivity inspection is performed simultaneously with the application of the clear paint. Then, the painting process concerning Embodiment 3 is complete | finished by implementing a drying process (step S17).

  From the above description, in the electrostatic coating apparatus according to the first and second embodiments, the object to be coated is based on the bell-side current that flows when the coating gun coats the object to be coated and the earth-side current that flows from the object to be grounded. Conduct conductivity inspection of the paint. Therefore, by using the electrostatic coating apparatus according to the first and second embodiments, it is possible to advance the coating process while performing the conductivity inspection within the coating process without providing a separate conductivity inspection process.

  Thereby, in the painting process concerning Embodiment 3, since a process can be advanced with the earth electrode attached to the article to be coated, it is possible to reduce problems caused by the attachment and removal of the earth electrode. In addition, in the painting process according to the third embodiment, it is possible to perform reliable coating while confirming the conductivity in the painting process without having time for the conductivity inspection.

  In the example shown in FIG. 8, the conductivity test was performed in the primer coating process (steps S11 and S12), the base coating process (step S14), and the clear coating process (step S16). What is necessary is just to be able to implement in any one process of a process, a base coating process, and a clear coating process.

  In the above description, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the embodiments already described, and various modifications can be made without departing from the scope of the invention. It goes without saying that changes are possible.

DESCRIPTION OF SYMBOLS 1 Electrostatic coating apparatus 2 Electrostatic coating apparatus 10 To-be-coated object 11 To-be-coated fixture 12 Insulator 13 Base part 14 Ground electrode 15 Ammeter 16 Discharge part 20 Coating gun 21 Spray paint 22 High voltage application apparatus 23 Ground inspection Section 30 Bell coating machine 31 Booster circuit 32 Bleeder resistance 41 Total current measurement section 42 High voltage application section 43 Bell side current calculation section 50 Ground connection wiring

Claims (6)

A coating gun that is provided for at least one of a plurality of objects to be coated, and sprays paint toward the objects to be coated;
A bell-side current calculation unit that calculates a bell-side total current that is a total value of bell-side currents flowing from the coating gun to the plurality of objects to be coated;
A ground-side current measuring unit that measures a ground-side total current that is a total value of ground-side currents flowing from the plurality of objects to be grounded;
The plurality of the bell-side total current and the ground-side total current measured during electrostatic coating, and the bell-side total current and the ground-side total current in a state where the ground is correctly connected, An earth inspection unit for detecting an abnormal state of the earthing state of the object to be coated;
An electrostatic coating apparatus having:   The ground inspection unit includes a ratio between the bell-side total current and the ground-side total current measured during electrostatic coating, and the bell-side total current and the ground-side total current when the ground is correctly connected. The electrostatic coating apparatus according to claim 1, wherein an abnormal state of the ground state of the plurality of objects to be coated is detected based on a difference between the ratio and a reference value set based on the ratio. A plurality of ground electrodes for supporting the plurality of objects to be coated, connecting the plurality of objects to be grounded, and further comprising a workpiece fixing jig for supporting the plurality of objects to be coated; ,
The electrostatic coating apparatus according to claim 1, wherein the plurality of ground electrodes are electrically connected. A coating gun that is provided for at least one of a plurality of objects to be coated, and sprays paint toward the objects to be coated;
A bell-side current calculation unit that calculates a bell-side total current that is a total value of bell-side currents flowing from the coating gun to the plurality of objects to be coated;
A ground-side current measuring unit that measures a ground-side total current that is a total value of ground-side currents flowing from the plurality of objects to be grounded;
A method for inspecting conductivity in an electrostatic coating apparatus having
During electrostatic coating, the bell side total current and the ground side total current are calculated as measured values,
Conductivity for detecting an abnormal state of the ground state of the plurality of objects to be coated according to the magnitude relationship between the calculated total value of the measured value and the bell side total current and the ground side total current in a state where the ground is correctly connected Inspection method.   Set based on the ratio of the bell-side total current and the ground-side total current measured during electrostatic coating, and the ratio of the bell-side total current and the ground-side total current when the ground is correctly connected The conductivity inspection method according to claim 4, wherein an abnormal state of the ground state of the plurality of objects to be coated is detected based on a difference from a reference value to be applied.   The conductivity inspection method according to claim 4 or 5, wherein the conductivity inspection method is performed in at least one of a primer coating process, a base coating process, and a clear coating process.

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