JP6575416B2 - Electrostatic paint grounding inspection method - Google Patents

Description

  The present invention relates to a grounding state inspection method when electrostatic coating is performed on an object formed of an insulating material.

  When electrostatic coating is performed on an object formed of an insulating material, a conductive primer is applied to the surface in advance by non-electrostatic coating to impart conductivity to the object to be coated. It is necessary to ground the object to which the property is imparted. And in order to ensure coating quality and prevent the occurrence of sparks, the quality of the ground state of the object to be coated is inspected before electrostatic coating.

  As an inspection method of the ground state, for example, in the following patent document, the surface of the object to be coated is charged by applying a charge to the object to be coated, and then the surface potential of the object to be coated is measured. By doing so, it is disclosed to inspect the ground state of the object to be coated.

JP-A-2005-58998

  However, in the ground state inspection method disclosed in the above patent document, a step of applying a conductive primer in advance to the surface of the object to be coated is required, and further, a step of applying a charge to the object to be coated; It is necessary to provide inspection-specific steps such as a step of measuring the charge amount of the object to be coated and a step of determining whether or not the measured charge amount is within a predetermined range. For this reason, there is a problem that not only the process associated with the inspection becomes complicated, but also the inspection cost increases.

  The present invention has been made in order to solve such a technical problem, and it is possible to easily inspect the ground state by a simple method and to reduce the cost of the ground state of the electrostatic coating. It aims to provide a method.

  A grounding state inspection method for electrostatic coating according to the present invention is a grounding state inspection method for electrostatic coating in which electrostatic coating is performed using a coating machine, and a water-based paint is statically applied to an object to be coated formed of an insulating material. A step of installing a ground connection member made of a metal material on the object to be coated; a step of applying a high voltage to the coating machine; and a step of applying the coating machine when a high voltage is applied. It is characterized by comprising a step of approaching the ground connection member and measuring a current flowing through the coating machine, and a step of determining the ground state of the object to be coated based on the measurement.

  In the method for inspecting the ground state of electrostatic coating according to the present invention, a high voltage is applied to the coating machine in a state where the water-based paint is not electrostatically coated on the object to be coated formed of the insulating material, and the coating machine is coated. The current flowing through the coating machine is measured while approaching the object, and the ground state of the object to be coated is determined based on the measurement result. That is, in the ground state inspection method of the present invention, it is not necessary to apply the conductive primer to the surface of the conventional object in advance by non-electrostatic coating. Moreover, it is not necessary to provide a dedicated process such as a conventional charge applying process, and the ground state can be inspected by using a coating machine. As a result, the inspection method becomes simpler than in the prior art, and the ground state can be easily inspected. In addition, the cost can be reduced and the effect of improving the inspection efficiency can be expected.

  In the ground state inspection method for electrostatic coating according to the present invention, the current is measured with a pin electrode provided on the coating machine, or the coating machine includes a rotary atomizing head, and the rotary atomizing head It is preferable to measure the electric current in a state where the coating material is supplied. In this way, it is possible to increase the change in the current flowing through the coating machine as the coating machine approaches, so that it is possible to reliably grasp the change in the current and improve the accuracy of the ground state inspection.

  According to the present invention, it is possible to easily inspect the ground state with a simple method and to reduce the cost.

It is the schematic which shows the structure of the ground condition inspection apparatus of the electrostatic coating which concerns on embodiment. It is a flowchart which shows the ground state inspection method of the electrostatic coating which concerns on embodiment. It is a figure which shows the relationship between the electric current integrated value in case with earth | ground, and a threshold value. It is a figure which shows the relationship between the electric current integrated value in the case of no earth | ground, and a threshold value.

  Hereinafter, an embodiment of a grounding state inspection method for electrostatic coating according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating the configuration of an electrostatic coating ground state inspection device (hereinafter, simply referred to as a ground state inspection device) according to an embodiment. The ground state inspection apparatus 1 of the present embodiment has the same structure as an existing coating apparatus because an existing coating apparatus that performs electrostatic coating is used. That is, the ground state inspection apparatus 1 mainly includes a coating machine 2 for performing electrostatic coating on the object 7 to be coated, a current measuring unit 3 for measuring a current flowing through the coating machine 2, and a coating machine 2. A voltage application unit 4 that applies a voltage, a high voltage controller 5 that controls a high voltage applied to the coating machine 2, and a device that includes the coating machine 2, a current measurement unit 3, a voltage application unit 4, and a high voltage controller 5. And a control unit 6 that performs control.

  The coating machine 2 is a so-called rotary atomizing type coating machine, and is configured to have an air motor, a paint passage, a turbine air passage, and the like in addition to the rotary atomizing head 2a attached to the tip. The rotary atomizing head 2a is rotated at high speed by an air motor, and sprays the paint by atomizing the paint using the centrifugal force generated by the high speed rotation. The rotary atomizing head 2a is formed into a bell shape or a cup shape using, for example, a conductive metal material, and is a paint sprayed from the rotary atomizing head 2a with a negative electrostatic voltage applied by the voltage application unit 4. Can be charged on the negative electrode side.

  The current measuring unit 3 measures a current (current value) flowing through the coating machine 2 when a high voltage is applied to the rotary atomizing head 2 a of the coating machine 2, and outputs the measured result to the control unit 6. The voltage application unit 4 generates a high voltage to be applied to the rotary atomizing head 2a of the coating machine 2, and is configured to include, for example, a voltage generation unit and a voltage boosting unit (not shown). . The voltage application unit 4 is connected to the high voltage controller 5 and operates in response to a control command from the high voltage controller 5. Further, the voltage application unit 4 is connected to the control unit 6. The high voltage controller 5 controls the voltage application unit 4 so as to adjust the voltage applied to the rotary atomizing head 2 a of the coating machine 2. The current measuring unit 3, the voltage applying unit 4, and the high voltage controller 5 may be arranged inside the coating machine 2 so as to be accommodated in the coating machine 2, or arranged outside the coating machine 2. May be.

  The control unit 6 is mainly configured by a computer including a CPU, a ROM, and a RAM, for example, and performs each control of the entire ground state inspection apparatus 1 based on each program stored in advance. Moreover, the control part 6 receives the electric current measured by the electric current measurement part 3, and performs the test | inspection of the earth state in the to-be-coated article 7 based on the change of an electric current.

  The article 7 is a front bumper or a rear bumper of an automobile, for example, and is formed of an insulating material such as polypropylene. The article 7 is placed on the jig 9 so that the coating surface faces outward (that is, on the side close to the coating machine 2). An earth connection member 8 made of a metal material is installed at one end of the article 7 to be coated. The ground connection member 8 is exposed on the article 7 so as to face the coating machine 2. In order to minimize the influence on the painting due to the installation of the ground connection member 8, it is preferable to use a ground connection member 8 having a small area and shape, such as a clip or a staple. Further, the earth connection member 8 is grounded via a conducting wire 10.

  Hereinafter, the ground state inspection method for electrostatic coating (hereinafter, abbreviated as the ground state inspection method) according to the present embodiment will be described with reference to FIG. The ground state inspection method of the present embodiment is performed in a state where the water-based paint is not electrostatically coated on the article 7 to be coated. The water-based paint here refers to a paint having a low resistance value, for example, a primer paint. Note that the ground state inspection method of the present embodiment does not include a step of previously applying a conductive primer to the surface of the object to be coated, unlike the conventional method, and the grounding member 8 is installed on the object 7 to be grounded. Connecting member installation step S1, voltage application step S2 for applying a high voltage, current measurement step S3 for measuring the current flowing through the rotary atomizing head 2a of the coating machine 2, and ground for determining the ground state of the article 7 to be coated A state determination step S4.

  In the ground connection member installation step S <b> 1, an operator installs the ground connection member 8 made of a metal material at one end of the article 7 to be coated. At this time, in order to facilitate the approach of the coating machine 2 later, it is preferable that the ground connection member 8 is disposed so as to face the coating machine 2 and is installed on the article 7 to be exposed.

  In a voltage application step S2 subsequent to the ground connection member installation step S1, a high voltage is applied to the rotary atomizing head 2a of the coating machine 2 via the voltage application unit 4. In the current measurement step S3 subsequent to the voltage application step S2, the current flowing through the rotary atomizing head 2a is measured via the current measurement unit 3 while bringing the coating machine 2 close to the ground connection member 8 in a non-contact state. At this time, the current is measured in a state where the water-based paint is supplied to the rotary atomizing head 2a of the coating machine 2. The current measuring unit 3 outputs the measurement result to the control unit 6. In addition, what is necessary is just to set suitably the approach distance with the earth connection member 8 in the coating machine 2, and the time concerning approach based on the magnitude | size of the coating machine 2, the shape of the earth connection member 8, etc. FIG.

  Moreover, it may replace with the electric current measurement in the state which supplied the aqueous coating material to the above-mentioned rotary atomization head 2a, and may perform the electric current measurement in the state which provided the pin electrode in the coating machine 2. FIG. By doing in this way, since the change of the electric current accompanying the approach of the coating machine 2 can be enlarged, there exists an effect which grasps | ascertains the change of an electric current reliably and improves the precision of a ground state test | inspection.

  In the ground state determination step S4 following the current measurement step S3, the control unit 6 receives the current output from the current measurement unit 3, and determines the ground state based on the change in current. The change in current is performed, for example, by analyzing a current waveform. Examples of the current waveform analysis method include a method of adding changes per time (current integration method), a method of analyzing the reached current, and a method of analyzing a current change slope. In this embodiment, the current integration method is used, and therefore the control unit 6 calculates the current integration value based on the current output from the current measurement unit 3.

  After calculating the current integrated value, the control unit 6 compares the obtained current integrated value with a preset threshold value. When the integrated current value is equal to or greater than the threshold value, the control unit 6 determines that the ground state of the article 7 is normal. On the other hand, when the current integrated value is less than the threshold value, the control unit 6 determines that there is an abnormality in the ground state of the article 7 and notifies the operator or the like by voice or / and light.

  Hereinafter, a case where the ground is normally grounded (with ground) and a case where the ground is not grounded (without ground) will be described by comparing FIG. 3 (with ground) and FIG. 4 (without ground). 3 and 4, the current (that is, the current consumption value) is indicated by a broken line, the current integrated value is indicated by a solid line, and the threshold value is indicated by a one-dot chain line.

  When the coating machine 2 approaches the ground connection member 8, the electric field formed between the coating machine 2 and the ground connection member 8 is discharged from the rotary atomizing head 2 a, and the current is grounded via the ground connection member 8 and the lead wire 10. Flows to the side. When the article 7 is normally grounded via the ground connection member 8 and the conductive wire 10, the amount of discharge from the rotary atomizing head 2a becomes relatively large, and therefore flows through the rotary atomizing head 2a. The current is also relatively large. Therefore, the current integrated value is also relatively large. The control unit 6 compares the current integrated value with a threshold value, and determines that the ground state of the article 7 is normal when the current integrated value is equal to or greater than the threshold value (see FIG. 3).

  When it is determined that the grounding state of the article 7 is normal, the control unit 6 controls the movement of the coating machine 2 so as to be placed at the coating position, and further the water-based paint on the rotary atomizing head 2a of the coating machine 2. To supply. Then, the coating machine 2 sprays a water-based paint charged on the negative electrode to the ground connection member 8, and moves toward the object 7 while moving the ground connection member 8 from the coating start position in a predetermined direction as the coating start position. Then, coat them in parallel and partially overlapping.

  On the other hand, when the article 7 is not grounded via the ground connection member 8 and the conductive wire 10, the electric charge applied to the article 7 by the rotary atomizing head 2a of the coating machine 2 is It will stay on the object 7. Accordingly, the amount of discharge from the rotary atomizing head 2a is relatively small. For this reason, the current flowing through the rotary atomizing head 2a is also relatively small, and the integrated current value is also relatively small. When the integrated current value is less than the threshold value (see FIG. 4), the control unit 6 determines that there is an abnormality in the ground state of the article 7 and informs the operator or the like by voice or / and light. Inform.

  In the ground state inspection method of the present embodiment, in a state where the water-based paint is not electrostatically coated on the article 7, the coating machine 2 flows through the rotary atomizing head 2 a of the painting machine 2 while approaching the article 7. The current is measured, a current integrated value is calculated based on the measured current, and further, compared with a threshold value, the ground state of the article 7 is inspected. That is, in the ground state inspection method of the present embodiment, it is not necessary to apply the conductive primer to the surface of the conventional object in advance by non-electrostatic coating. In addition, it is not necessary to provide a dedicated process such as a conventional charge application process, and the ground state can be inspected by utilizing an existing coating apparatus. As a result, the inspection method becomes simpler than in the prior art, and the ground state can be easily inspected. In addition, the inspection cost can be reduced, and the effect of improving the inspection efficiency can be expected.

  Furthermore, in the ground state inspection method according to the present embodiment, the existing coating apparatus having the coating machine 2, the current measuring unit 3, the voltage applying unit 4, the high voltage controller 5, and the control unit 6 is used to Since the ground state can be inspected, the equipment cost can be reduced as compared with the conventional case where a dedicated device for ground state inspection is provided.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 1 Ground state inspection apparatus 2 Coating machine 2a Rotating atomizing head 3 Current measurement part 4 Voltage application part 5 High voltage controller 6 Control part 7 Object 8 Ground connection member 9 Jig 10 Lead wire

Claims (3)

An electrostatic coating grounding inspection method for performing electrostatic coating using a coating machine,
In a state where the conductive primer is not applied to the object to be coated formed of the insulating material,
Installing an earth connection member made of a metal material on the object to be coated;
Applying a high voltage to the coating machine;
Bringing the coating machine close to the ground connection member when a high voltage is applied, and measuring a current flowing through the coating machine;
And a step of determining a ground state of the object to be coated based on the measurement.   The method for inspecting the ground state of electrostatic coating according to claim 1, wherein the current is measured with a pin electrode provided on the coating machine.   The electrostatic coating ground state inspection method according to claim 1, wherein the coating machine includes a rotary atomizing head, and the current is measured in a state where a paint is supplied to the rotary atomizing head.

Images