JP2016001519A - Paint drying apparatus and paint drying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the surface temperature even of a painted object, having a complicated shape, uniform with high accuracy.SOLUTION: A paint drying apparatus includes a position detector 1a for holding three-dimensional proportional control constant information D3 that is set based on the three-dimensional heat capacity information of a painted object 10, and detecting a three-dimensional position, i.e., the heating object position of the painted object 10 by an induction heating coil 3, a temperature detector 1b for detecting the temperature of the painted object 10 corresponding to the three-dimensional position detected by the position detector 1a, and a temperature control unit 1c performing proportional control of the energization power to the induction heating coil 3, by setting the proportional control constant P' so that the temperature of the painted object 10, detected by the temperature detector 1b at the three-dimensional position, based on the three-dimensional proportional control constant information D3 of the painted object 10 corresponding to the three-dimensional position detected by the position detector 1a, becomes the set temperature.

Description

  The present invention relates to a coating drying apparatus and a coating drying method that can make the surface temperature of an object to be coated highly accurate and uniform even if the object has a complicated shape.

  Conventionally, a hot-air drying furnace has been used for painting and drying automobile bodies and the like. In this hot air drying furnace, the hot air temperature has been set to be equal to or higher than the standard baking temperature in order to prevent poor baking at locations with a large heat capacity. For this reason, the portion having a small heat capacity is excessively heated, which has prevented energy saving. Further, since the object to be coated is heated by indirect heat input in the hot air drying furnace, it took a long time for the object to reach the desired temperature. On the other hand, due to the nature of the paint, yellowing or carbonization occurs when an object to be coated is placed in an atmosphere at or above a predetermined baking temperature.

  In order to save energy and improve the quality of the coating film, there are some which perform coating drying by an induction heating method using an induction heating coil. In the induction heating method, a magnetic line of force is generated around the induction heating coil by flowing a high-frequency current through the induction heating coil, and the conductive object to be heated nearby is affected by the magnetic field line and is heated inside the object to be heated. Causes eddy currents. And the to-be-heated body generates Joule heat by this eddy current, and is heated directly from the inside.

  As an apparatus using this induction heating method, for example, Patent Document 1 discloses a coating drying apparatus that can change the shape of the induction heating coil and adjust the strength and area of the magnetic flux density emitted from the induction heating coil. Have been described. For this reason, in patent document 1, even if it is a complicated-shaped to-be-coated object, the surface temperature of a to-be-coated object can be made uniform. In Patent Document 1, the surface temperature of the object to be coated is adjusted by detecting the surface temperature of the object to be coated and adjusting the output, heating position, and heating time of the induction heating coil.

JP 2010-281490 A

  In the induction heating method described above, the temperature is generally controlled using a PID control device so that the surface temperature of the object to be coated is uniform. However, since the temperature control target point of the object to be coated by the induction heating coil moves every moment, it is difficult to perform highly accurate temperature control using integral control and differential control in addition to proportional control. On the other hand, the temperature control points of objects to be painted such as automobile bodies are often different in heat capacity and heat dissipation due to the complicated shape of the object to be coated, and the surface temperature of the object to be coated is more accurate and uniform. Difficult to make.

  The present invention has been made in view of the above, and provides a coating drying apparatus and a coating drying method capable of accurately and uniformly making the surface temperature of an object to be coated even if the object has a complicated shape. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a paint drying apparatus according to the present invention moves an induction heating coil around the object to be coated and dries the paint applied to the object to be coated. A three-dimensional proportional control constant information holding unit for holding three-dimensional proportional control constant information set based on the three-dimensional heat capacity information of the object to be coated, and heating the object by the induction heating coil. A position detection unit that detects a three-dimensional position that is a target position, a temperature detection unit that detects the temperature of the object to be coated corresponding to the three-dimensional position detected by the position detection unit, and 3 detected by the position detection unit Based on the three-dimensional proportional control constant information of the object corresponding to the three-dimensional position, a proportional control constant is set so that the temperature of the object detected by the temperature detection unit at the three-dimensional position becomes a set temperature. Induction Characterized by comprising a temperature control unit for proportional control of the energization power to the coil.

  The paint drying apparatus according to the present invention further includes a three-dimensional temperature deviation integrated value holding unit that holds a three-dimensional temperature deviation integrated value at the same three-dimensional position where the induction heating coil repeatedly moves and heats. The temperature control unit integrates and compensates the set proportional control constant based on the three-dimensional temperature deviation integral value corresponding to the three-dimensional position detected by the position detection unit.

  The paint drying method according to the present invention is a paint drying method in which an induction heating coil is moved around the object to be coated, and the paint applied to the paint is dried. The three-dimensional position of the induction heating coil The proportional control constant is calculated based on the deviation between the set temperature of the object to be coated and the detected temperature detected at the three-dimensional position, and the object to be coated is calculated with respect to the calculated proportional control constant. A proportional control constant corresponding to the three-dimensional position is set based on the three-dimensional proportional control constant information set based on the three-dimensional heat capacity information, and the three-dimensional position is determined using the set proportional control constant. Proportional control of the energization power to the induction heating coil is performed so that the temperature at is a set temperature.

  Further, the paint drying method according to the present invention, in the above-described invention, holds the three-dimensional temperature deviation integral value at the same three-dimensional position where the induction heating coil repeatedly moves and heats updatable, and updates the current value at the three-dimensional position. The set proportional control constant is integrated and compensated using the three-dimensional temperature deviation integral value.

  According to this invention, the three-dimensional proportional control constant information holding unit holds the three-dimensional proportional control constant information set based on the three-dimensional heat capacity information of the object to be coated, and the position detecting unit is based on the induction heating coil. A three-dimensional position that is a heating target position of the object to be coated is detected, a temperature control unit detects a temperature of the object to be coated corresponding to the three-dimensional position detected by the position detection unit, and a temperature control unit, Based on the three-dimensional proportional control constant information of the object corresponding to the three-dimensional position detected by the position detector, the temperature of the object detected by the temperature detector at the three-dimensional position becomes a set temperature. A proportional control constant is set in the control unit to perform proportional control of the electric power supplied to the induction heating coil. As a result, even if the object has a complicated shape, the surface temperature of the object can be made uniform with high accuracy.

FIG. 1 is a schematic diagram showing the overall configuration of a paint drying apparatus according to Embodiment 1 of the present invention. FIG. 2 is a detailed block diagram showing the configuration of the temperature control unit shown in FIG. FIG. 3 is a diagram illustrating an example of three-dimensional proportional control constant information. FIG. 4 is a schematic diagram showing an overall configuration of a paint drying apparatus according to Embodiment 2 of the present invention. FIG. 5 is a diagram illustrating an example of a three-dimensional temperature deviation integrated value. FIG. 6 is a detailed block diagram showing the configuration of the temperature control unit shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

(Embodiment 1)
[overall structure]
FIG. 1 is a schematic diagram showing the overall configuration of a paint drying apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the paint drying apparatus includes a control unit 1, a temperature distribution acquisition unit 2, an induction heating unit 4 realized by a robot arm in which an induction heating coil 3 is coupled to the tip, a storage unit 5, and a display unit. 6 and the operation unit 7 are connected.

  The temperature distribution acquisition unit 2 acquires temperature distribution information of the object 10 that has been loaded. Specifically, the temperature distribution acquisition unit 2 is a three-dimensional infrared thermography, and acquires temperature distribution information of the object to be coated 10. This temperature distribution information is stored as temperature distribution information D2 in the storage unit 5 via the control unit 1. In the first embodiment, the temperature distribution acquisition unit 2 is installed on the ceiling 13.

  The induction heating coil 3 is, for example, a coil wound in a circular shape. The induction heating coil 3 can be changed in position and posture under the control of the control unit 1 by driving a robot arm attached to the ceiling 13. The induction heating coil 3 generates a magnetic field by a high frequency current supplied from a power source (not shown). The object to be coated 10 is a metal, and is heated by receiving an electric field from the induction heating coil 3 and generating an eddy current.

  The storage unit 5 holds the three-dimensional shape information D1 of the article 10 to be coated. The three-dimensional shape information D1 is, for example, three-dimensional CAD data. In addition to the above-described temperature distribution information D2, the storage unit 5 divides the object to be coated 10 into meshes, as will be described later, and corresponds to the three-dimensional heat capacity information for each mesh, and is proportional to the three-dimensional for each mesh. Control constant information D3 is held.

  The display unit 6 displays and outputs various information such as the three-dimensional shape information D1, the temperature distribution information D2, the three-dimensional proportional control constant information D3, and the three-dimensional movement path RT of the induction heating coil 3. The three-dimensional shape information D1, the temperature distribution information D2, the three-dimensional proportional control constant information D3, and the three-dimensional movement path RT of the induction heating coil 3 are superposed and output at least under the control of the control unit 1. can do.

  The operation unit 7 issues a control instruction to the control unit 1. The operation unit 7 is realized by a keyboard or a pointing device.

  A conveyor 12 that conveys the article to be coated 10 is disposed on the floor 11. The object to be coated 10 is, for example, an automobile body, and is carried to a predetermined position by the conveyor 12 in a state where a water-based paint is applied. When the object to be coated 10 is carried in, the control unit 1 drives and controls the induction heating unit 4 and controls the three-dimensional position and posture of the induction heating coil 3 in order to burn the paint applied to the object to be coated 10. Meanwhile, the object to be coated 10 is induction-heated.

  The control unit 1 includes a position detection unit 1a, a temperature detection unit 1b, and a temperature control unit 1c. The position detection unit 1a detects a three-dimensional position that is a heating target position of the object to be coated 10 by the induction heating coil 3 based on the driving state of the robot arm. The temperature detection unit 1b detects a temperature corresponding to the three-dimensional position detected by the position detection unit 1a based on the temperature distribution information D2 acquired by the temperature distribution acquisition unit 2. Based on the three-dimensional proportional control constant information D3 of the workpiece 10 corresponding to the three-dimensional position detected by the position detection unit 1a, the temperature control unit 1c detects the object 10 detected by the temperature detection unit 1b at the three-dimensional position. A proportional control constant is set so that the temperature becomes the set temperature, and proportional control of the electric power supplied to the induction heating coil 3 is performed. As a result, when the induction heating coil 3 moves along the three-dimensional movement path RT to heat the object 10 to be coated, an appropriate proportional control constant corresponding to the heat capacity of each part of the object 10 is set every moment, and the heat capacity is set. Even with different complicated objects 10 to be coated, the temperature distribution can be made uniform with high accuracy.

  The control unit 1 moves while maintaining the coil forming surface of the induction heating coil 3 parallel to the surface of the object to be coated 10 and keeping the gap with the object to be coated 10 constant. In addition, the three-dimensional movement path RT of the induction heating coil 3 is set in an order from a region having a large heat capacity to a region having a small heat capacity. For example, the region E1 shown in FIG. 1 is a rocker portion, and is in contact with the conveyor 12 and has a large heat capacity because of being thick, and therefore preferentially performs induction heating. Since the region E2 has a complicated shape and is difficult to induction heat, induction heating is performed after the induction heating of the region E1. In addition, since the region E3 has a small plate thickness and a small heat capacity, the priority of the induction heating order is last. In this way, by setting the moving path of the induction heating coil 3 from the region having a large heat capacity toward the region having a small heat capacity, the temperature difference of the entire induction heating region at the time when one induction heating is completed can be reduced. .

[Detailed configuration of temperature controller]
Next, the temperature control of the temperature control unit 1c will be described based on the detailed block diagram showing the configuration of the temperature control unit 1c shown in FIG. As shown in FIG. 2, the set temperature set as the average temperature of the article 10 is input to the calculation unit 31. Further, the detected temperature detected by the temperature detection unit 1b at the current three-dimensional position is input to the calculation unit 31. The calculation unit 31 outputs a deviation Δt between the set temperature and the detected temperature to the proportional control constant calculation unit 32. The proportional control constant calculation unit 32 holds the relationship of the proportional control constant P corresponding to the value of the deviation Δt, calculates the proportional control constant P corresponding to the input deviation Δt, and outputs it to the proportional control constant setting unit 33. .

  The current three-dimensional position detected by the position detection unit 1a is input to the proportional control constant setting unit 33. The proportional control constant setting unit 33 acquires the three-dimensional proportional control constant information D3 corresponding to the input current three-dimensional position, corrects the proportional control constant P to the proportional control constant P ′, and this corrected proportional control constant. P ′ is output to the induction heating coil power supply 34. The induction heating coil power supply 34 controls the energization power to the induction heating coil 3 based on the input proportional control constant P ′. The control of the energization power is, for example, increase / decrease control of the high-frequency current value flowing through the induction heating coil 3.

  As shown in FIG. 3, the three-dimensional proportional control constant information D3 is a structure or material such as the thickness of the object to be coated 10 for each divided region divided in advance into a mesh based on the three-dimensional shape information D1. The three-dimensional heat capacity information resulting from the above is obtained and preset for each divided region based on the three-dimensional heat capacity information. For example, the three-dimensional proportional control constant information D3 is set such that the proportional control constant P ′ is set to a value exceeding 1 in a divided region where the heat capacity is large compared to the average heat capacity, and the heat capacity is small in the divided region compared to the average heat capacity. The proportional control constant P ′ is set to a value less than 1. The determination as to whether or not the three-dimensional position of the induction heating coil 3 has entered a certain divided area is, for example, the case where the center position of the heating temperature profile of the induction heating coil 3 has entered a certain divided area. Note that the three-dimensional proportional control constant D3 may take into account not only the heat capacity but also the amount of heat released based on the structure and material of the object 10 to be coated.

  In the first embodiment, in addition to the calculation of the proportional control constant P by the deviation Δt between the set temperature and the detected temperature, the temperature control unit 1c performs the heat capacity at the three-dimensional position of the object 10 to be coated as the induction heating coil 3 moves. Since the temperature control for correcting the proportional control constant P to the proportional control constant P ′ using the three-dimensional proportional control constant information D3 that takes into account the change in the amount of heat release is performed with movement, the heat capacity in each part of the object 10 to be coated In addition, the temperature non-uniformity associated with the difference in the heat radiation amount can be eliminated, and the surface temperature of the object 10 can be made uniform with high accuracy. In particular, since the temperature difference between the three-dimensional positions of the object to be coated 10 can be reduced, it is possible to control at a high temperature allowed by the paint, and shorten the coating drying time. In addition, the shortening of the coating drying time shortens the energization time to the induction heating coil 3, and therefore energy saving of the entire coating drying apparatus can be achieved.

(Embodiment 2)
[overall structure]
FIG. 4 is a schematic diagram showing an overall configuration of a paint drying apparatus according to Embodiment 2 of the present invention. In the second embodiment, the temperature control unit 1d corresponds to the temperature control unit 1c of the first embodiment, but this temperature control unit 1d further performs three-dimensional temperature deviation integration for each divided region, and this three-dimensional temperature The proportional control constant P ′ is integrated and compensated in consideration of the deviation integral value. The storage unit 5 holds a three-dimensional temperature deviation integral value D4 that is an integral value of the deviation Δt at the same three-dimensional position in an updatable manner. That is, as shown in FIG. 5, the integrated value of each divided region is updated as the three-dimensional temperature deviation integrated value D4 moves each time the induction heating coil 3 moves along the three-dimensional movement path RT. The three-dimensional temperature deviation integral value D4 is an integral value of the deviation Δt a predetermined number of times until the previous movement. Other configurations of the paint drying apparatus are the same as those in the first embodiment.

[Detailed configuration of temperature controller]
Next, the temperature control of the temperature control unit 1d will be described based on the detailed block diagram showing the configuration of the temperature control unit 1d shown in FIG. As shown in FIG. 6, the set temperature set as the average temperature of the article 10 is input to the calculation unit 31. Further, the detected temperature detected by the temperature detection unit 1b at the current three-dimensional position is input to the calculation unit 31. The calculation unit 31 outputs the deviation Δt between the set temperature and the detected temperature to the proportional control constant calculation unit 32 and the proportional control constant compensation setting unit 35.

  The proportional control constant calculation unit 32 holds the relationship of the proportional control constant P corresponding to the value of the deviation Δt, calculates the proportional control constant P corresponding to the input deviation Δt, and outputs it to the proportional control constant setting unit 33. . The current three-dimensional position detected by the position detection unit 1a is input to the proportional control constant setting unit 33. The proportional control constant setting unit 33 acquires the three-dimensional proportional control constant information D3 corresponding to the input current three-dimensional position, corrects the proportional control constant P to the proportional control constant P ′, and this corrected proportional control constant. P ′ is output to the calculation unit 36.

  On the other hand, the current three-dimensional position detected by the position detection unit 1a is input to the proportional control constant compensation setting unit 35. The proportional control constant compensation setting unit 35 acquires a three-dimensional temperature deviation integrated value D4 that is an integrated value of the deviation Δt so far, and adds the deviation Δt input this time to the acquired three-dimensional temperature deviation integrated value D4. Integration processing is performed, and the new integration value after the integration processing is updated as a three-dimensional temperature deviation integration value D4, and the compensation value Pα of the proportional control constant is calculated based on the updated three-dimensional temperature deviation integration value D4. To 36. This three-dimensional temperature deviation integrated value D4 is still the detected temperature and the set temperature even when the temperature control using the proportional control constant P ′ set by the proportional control constant calculating unit 32 and the proportional control constant setting unit 33 is performed. This is an index indicating whether or not a deviation Δt occurs.

  The calculation unit 36 increases or decreases the compensation value Pα by the proportional control constant P ′, and outputs the integral compensated proportional control constant P ″ to the induction heating coil power supply 34. The induction heating coil power supply 34 controls the energization power to the induction heating coil 3 based on the input proportional control constant P ″.

  In the second embodiment, in addition to the first embodiment, the temperature deviation that cannot be eliminated only by proportional control is subjected to integral compensation for each three-dimensional position by the proportional control constant compensation setting unit 35. The temperature non-uniformity accompanying the difference in the heat capacity and the heat radiation amount in each part of the object 10 can be eliminated, and the surface temperature of the object 10 can be made uniform with high accuracy. In particular, since the temperature difference between the three-dimensional positions of the object to be coated 10 can be reduced, it is possible to control at a high temperature allowed by the paint, and shorten the coating drying time. In addition, the shortening of the coating drying time shortens the energization time to the induction heating coil 3, and therefore energy saving of the entire coating drying apparatus can be achieved.

  In Embodiments 1 and 2 described above, one induction heating coil 3 is used. However, the present invention is not limited to this, and a plurality of induction heating coils 3 may be provided. Further, a plurality of temperature distribution acquisition units 2 may be provided to acquire the temperature distribution information D2. In this case, it is preferable that the induction heating coils 3 and the temperature distribution acquisition units 2 are paired.

  Moreover, in embodiment mentioned above, it demonstrates on the assumption that it is a circular coil to which the coil diameter of the induction heating coil 3, the number of coil turns, the pitch interval, etc. were fixed. However, the induction heating coil 3 may have different heat input characteristics using various shapes and materials.

DESCRIPTION OF SYMBOLS 1 Control part 1a Position detection part 1b Temperature detection part 1c, 1d Temperature control part 2 Temperature distribution acquisition part 3 Induction heating coil 4 Induction heating part 5 Memory | storage part 6 Display part 7 Operation part 10 To-be-painted object 11 Floor 12 Conveyor 13 Ceiling 31 , 36 Calculation unit 32 Proportional control constant calculation unit 33 Proportional control constant setting unit 34 Induction heating coil power supply 35 Proportional control constant compensation setting unit D1 Three-dimensional shape information D2 Temperature distribution information D3 Three-dimensional proportional control constant information D4 Three-dimensional temperature deviation integration Value P, P ′, P ″ Proportional control constant Pα Compensation value RT 3D movement path Δt Deviation

Claims (4)

A coating drying apparatus that moves an induction heating coil around a workpiece and dries the coating applied to the coating,
A three-dimensional proportional control constant information holding unit for holding three-dimensional proportional control constant information set based on the three-dimensional heat capacity information of the object to be coated;
A position detection unit that detects a three-dimensional position that is a position to be heated of the object to be coated by the induction heating coil;
A temperature detector that detects the temperature of the object to be coated corresponding to the three-dimensional position detected by the position detector;
Based on the three-dimensional proportional control constant information of the object corresponding to the three-dimensional position detected by the position detector, the temperature of the object detected by the temperature detector at the three-dimensional position becomes a set temperature. A temperature control unit that sets a proportional control constant to perform proportional control of the energization power to the induction heating coil;
A paint drying apparatus characterized by comprising: A three-dimensional temperature deviation integral value holding unit for holding a three-dimensional temperature deviation integral value at the same three-dimensional position where the induction heating coil repeatedly moves and heats;
The said temperature control part carries out integral compensation of the set said proportional control constant based on the said three-dimensional temperature deviation integrated value corresponding to the three-dimensional position which the said position detection part detected. Paint drying equipment. A coating drying method for moving an induction heating coil around the object to be coated and drying the paint applied to the object to be coated,
Calculating a proportional control constant based on a deviation between a set temperature of the object to be coated corresponding to the three-dimensional position of the induction heating coil and a detected temperature detected at the three-dimensional position;
For the calculated proportional control constant, set a proportional control constant corresponding to the three-dimensional position based on the three-dimensional proportional control constant information set based on the three-dimensional heat capacity information of the object to be coated,
A paint drying method characterized by performing proportional control of the electric power supplied to the induction heating coil so that the temperature at the three-dimensional position becomes a set temperature using the set proportional control constant.   The three-dimensional temperature deviation integral value at the same three-dimensional position where the induction heating coil repeatedly moves and heats is maintained in an updatable manner, and the set proportionality is determined using the current three-dimensional temperature deviation integral value at the three-dimensional position. 4. The coating drying method according to claim 3, wherein the control constant is integrated and compensated.

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