JP2016200289A - Coating drying device and coating drying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating drying device and a coating drying method in which a coating material is dried in a further short time in consideration of a degree of polymerization of resin type coating that is cured through polymerization reaction and an energy saving can be attained.SOLUTION: A printing control part 1d sets a target printing temperature Ta, starts a printing operation using an induction heating coil 3, then performs a controlling operation such that when a temperature detected by a temperature detecting part 1b becomes equal to or higher than a minimum printing temperature, a value in which accumulated lap value up to a previous time is added to a calculated lap value in which a differential printing time ranging from the printing temperature of previous time equal to or higher than the minimum printing temperature to the present printing temperature is multiplied by a printing time weighing coefficient value corresponding to a present printing temperature is calculated by accumulation as a present accumulated lap value; and when the present accumulated lap value exceeds a printing finish value in respect to the target printing temperature Ta, the printing using the induction heating coil 3 is finished under an assumption that the printing is completed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coating drying apparatus and a coating drying method capable of drying a coating in a short time and saving energy in consideration of the degree of polymerization of a resin-based coating cured by a polymerization reaction.

  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. And what was described in patent document 1 is adjusting the surface temperature of a to-be-coated object by detecting the surface temperature of the to-be-coated object and adjusting the output of the induction heating coil, the heating position, and the heating time. Therefore, since temperature control can be performed with higher accuracy than when a conventional drying furnace such as a mountain furnace is used, energy saving can be achieved.

JP 2010-281490 A

  By the way, the resin-based paint to be cured by the polymerization reaction has a minimum temperature at which polymerization by the blocking agent starts and a maximum temperature for preventing yellowing and carbonization of the coating film, as shown in FIG. The paint needs to be baked in the proper baking area E10 which is the temperature range between the lowest temperature and the highest temperature. When the baking temperature is low, it takes time to cure the paint, and when the baking temperature is high, the curing of the paint can be completed in a short time.

  When drying a resin-based paint that is cured by the above-described polymerization reaction using the above-described induction heating method, after reaching a high target baking temperature, this high target baking temperature is maintained for a certain baking time, Control was performed so that the paint reached the above-described proper baking area E10.

  However, even when the induction heating method described above is used, the resin-based paint that is cured by the polymerization reaction is polymerized when the minimum baking temperature is exceeded, even before reaching the high target baking temperature described above. In addition, a loss of time until reaching a high target baking temperature is generated, and energy saving is hindered.

  The present invention has been made in view of the above, and in consideration of the degree of polymerization of a resin-based paint to be cured by a polymerization reaction, the paint can be dried in a shorter time and energy saving can be achieved. It is an object of the present invention to provide a drying apparatus and a paint drying method.

  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 bakes the paint applied to the object to be coated. A position detection unit that detects a three-dimensional position that is a heating target position of the object to be coated by the induction heating coil, and a temperature of the object to be coated corresponding to the three-dimensional position detected by the position detection unit. A reference baking completion curve depicting a reference baking completion point is set in the appropriate baking area of the paint indicated by the temperature detection unit to be detected, the baking temperature and the baking time, and the points on the reference baking completion curve are baked Generate and set the baking temperature dependency of the baking completion value, which is a value obtained by multiplying the time and the rising temperature from the lowest baking temperature in the proper baking area to the baking temperature at the point on the reference baking completion curve. In addition, a target baking temperature is set, and the baking temperature dependency of the baking time weight coefficient value, which is a value obtained by dividing the baking completion value at the target baking temperature by the baking time to the reference baking completion point at each baking temperature. And after the start of baking using the induction heating coil, when the temperature detected by the temperature detection unit is equal to or higher than the minimum baking temperature, the previous time when the minimum baking temperature is exceeded. The cumulative value obtained by multiplying the difference baking time between the current baking temperature and the current baking temperature by the baking time weighting coefficient value corresponding to the current baking temperature and the previous cumulative polymerization value is added to the current cumulative value. If the current cumulative polymerization value exceeds the baking completion value for the target baking temperature, it is assumed that baking has been completed. And baking control unit for controlling to terminate the baked using an induction heating coil, and further comprising a.

  The paint drying apparatus according to the present invention is characterized in that, in the above invention, the reference baking completion curve, the baking temperature dependency of the baking completion value, and the baking temperature dependency of the baking time weight coefficient value are the proper baking. It is set corresponding to a discrete baking temperature between the lowest baking temperature and the highest baking temperature in the region.

  In the paint drying apparatus according to the present invention, in the above invention, the temperature detection unit has a temperature distribution map corresponding to the three-dimensional position, and the baking control unit has an entire area on the temperature distribution map. When the current accumulated polymerization value exceeds the baking completion value for the target baking temperature, the baking is completed, and there is a partial area where the current baking temperature is less than the target baking temperature in the area on the temperature distribution map. The induction heating coil is controlled to raise the temperature with respect to the partial area, and if there is a partial area in the area on the temperature distribution map where the current baking temperature exceeds the target baking temperature, the partial area On the other hand, the induction heating coil is controlled to lower the temperature.

  In the paint drying apparatus according to the present invention, in the above invention, the baking control unit controls the temperature of the partial region by increasing or decreasing the amount of current of the induction heating coil with respect to the partial region. Features.

  In the paint drying apparatus according to the present invention, in the above invention, the reference baking completion curve divides the appropriate baking area by a dividing curve that passes through the center of the baking time width in the appropriate baking area for each baking temperature. And among the divided areas, it is set in the area on the side where the baking time is short.

  In the paint drying apparatus according to the present invention, the target baking temperature is a temperature at which the baking completion value is maximized.

  The coating drying method according to the present invention is a coating drying method in which an induction heating coil is moved around the object to be coated, and the paint applied to the object to be coated is baked, and is indicated by the baking temperature and baking time. A reference baking completion curve in which a reference baking completion point is drawn in the appropriate baking area of the paint is set, and the reference baking is performed from the baking time of the point on the reference baking completion curve and the minimum baking temperature of the appropriate baking area. A baking completion value that is a value obtained by multiplying the temperature of the point on the completion curve up to the baking temperature is generated and set, a target baking temperature is set, and the baking completion value at the target baking temperature is set for each baking. A baking setting step of generating and setting a baking time weighting factor value which is a value divided by the baking time up to the reference baking completion point at the temperature; A temperature detection step of detecting a three-dimensional position that is a position to be heated of the object to be heated by the induction heating coil and detecting a temperature of the object to be coated corresponding to the detected three-dimensional position And when the temperature detected in the temperature detection step is equal to or higher than the minimum baking temperature, the current baking temperature is calculated for the difference baking time between the previous baking temperature and the current baking temperature that is equal to or higher than the minimum baking temperature. The cumulative polymerization value multiplied by the baking time weighting factor value corresponding to is added to the previous cumulative polymerization value as the current cumulative polymerization value, and the current cumulative polymerization value is burned to the target baking temperature. A baking control step for performing control to finish baking using the induction heating coil as a result of completion of baking when the value is exceeded. And butterflies.

  According to the present invention, after the baking process of the paint by the induction heating coil 3 is started, even when the baking temperature T reaches the target baking temperature Ta, when the temperature reaches the baking minimum temperature in the proper baking area E10. Since the degree of baking is determined in consideration of the degree of polymerization of the paint, the resin-based paint that is cured by the polymerization reaction can be baked in a short time and wasteful heating can be reduced. Therefore, energy saving can be achieved.

FIG. 1 is a schematic diagram showing the overall configuration of a paint drying apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a reference baking completion curve set by the baking setting unit shown in FIG. FIG. 3 is a diagram showing an example of the baking temperature dependence of the baking completion value generated using the reference baking completion curve shown in FIG. 4 is a diagram showing an example of the baking temperature dependency of the baking time weighting coefficient value generated using the reference baking completion curve shown in FIG. 2 and the baking temperature dependency of the baking completion value shown in FIG. . FIG. 5 is a flowchart showing a printing control processing procedure by the control unit shown in FIG. FIG. 6 is a diagram illustrating an example of a temperature distribution map and a cumulative polymerization value map. FIG. 7 is a diagram showing an example of setting of the reference baking completion curve shown in FIG.

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

(overall structure)
FIG. 1 is a schematic diagram showing the overall configuration of a paint drying apparatus according to an embodiment 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 a temperature distribution map D2 indicating the temperature distribution of the object 10 that has been loaded. Specifically, the temperature distribution acquisition unit 2 is a three-dimensional infrared thermography, and acquires a temperature distribution map D2 of the article 10 to be coated. The temperature distribution map D2 is sequentially stored 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 object to be coated 10 is coated with a resin-based paint that is cured by a polymerization reaction, and the object to be coated 10 is heated by the induction heating coil 3 to be cured and baked.

  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 map D2, the storage unit 5 holds baking information D3 described later and a cumulative polymerization value map D4 described later. The temperature distribution map D2 and the cumulative overlap value map D4 are divided into meshes corresponding to three-dimensional positions detected by the position detector 1a described later, and each mesh corresponds to a three-dimensional position. Note that the baking information D3 includes an appropriate baking area E10, a reference baking completion curve L, a baking temperature dependency L1 of the baking completion value, and a baking temperature dependency L2 of the baking time weight coefficient value.

  The display unit 6 displays and outputs various information such as the three-dimensional shape information D1, the temperature distribution map D2, the baking information D3, the cumulative polymerization value map D4, and the three-dimensional movement path RT of the induction heating coil 3. The three-dimensional shape information D1, the temperature distribution map D2, the cumulative polymerization value map D4, and the three-dimensional movement route 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 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, a baking setting unit 1c, and a baking control unit 1d. 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. Based on the temperature distribution information acquired by the temperature distribution acquisition unit 2, the temperature detection unit 1b generates a temperature distribution map corresponding to the three-dimensional position detected by the position detection unit 1a.

  The baking setting unit 1c sets a reference baking completion curve L in which the reference baking completion point is drawn in the appropriate baking region E10 of the paint indicated by the baking temperature and baking time, and baking points on the reference baking completion curve L A baking temperature dependency L1 of the baking completion value, which is a value obtained by multiplying the temperature and the rising temperature from the lowest baking temperature in the proper baking area E10 to the baking temperature at the point on the reference baking completion curve L, is generated and set. Next, while setting the target baking temperature, the baking temperature dependence L2 of the baking time weighting coefficient value, which is a value obtained by dividing the baking completion value at the target baking temperature by the baking time to the reference baking completion point at each baking temperature, is set. Generate and configure. The baking completion value is a value corresponding to the degree of polymerization of the paint, and the baking time weighting coefficient value is a value for correcting the value corresponding to the degree of polymerization corresponding to different baking temperatures.

  The baking control unit 1d controls the electric power supplied to the induction heating coil 3 so that the temperature of the object 10 detected by the temperature detection unit 1b at the three-dimensional position detected by the position detection unit 1a becomes the target baking temperature. In particular, when the temperature detected by the temperature detection unit 1b is equal to or higher than the minimum baking temperature after the start of baking using the induction heating coil 3 at the set target baking temperature, the baking control unit 1d is equal to or higher than the minimum baking temperature. A value obtained by adding the accumulated polymerization value up to the previous time to the accumulated polymerization value obtained by multiplying the difference baking time between the previous baking temperature and the current baking temperature by the baking time weight coefficient value corresponding to the current baking temperature. A cumulative calculation is performed as the current cumulative polymerization value, and when the current cumulative polymerization value exceeds the baking completion value for the target baking temperature, the baking using the induction heating coil 3 is terminated as the baking is completed. .

  The control unit 1 keeps the coil forming surface of the induction heating coil 3 parallel to the surface of the object to be coated 10, and repeatedly moves along the three-dimensional movement path RT while keeping the gap with the object to be coated 10 constant. To do. 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 processing of printing setting section)
Next, with reference to FIGS. 2 to 4, detailed processing of the baking setting unit 1 c will be described. FIG. 2 is a diagram illustrating an example of a reference baking completion curve L set by the baking setting unit 1c. As shown in FIG. 2, the completion of baking of the paint is achieved by setting it within the proper baking area E10 determined by the baking temperature and baking time. The minimum baking temperature in the proper baking area E10 is 130 ° C., and the maximum baking temperature is 170 ° C. In the proper baking area E10, a minimum baking time and a maximum baking time are set for each baking temperature. The minimum baking time of the proper baking area E10 is 10 minutes, and the maximum baking time is 60 minutes. In the excessive baking area E11 that exceeds the maximum baking temperature or exceeds the maximum baking time outside the proper baking area E10, yellowing or carbonization of the paint occurs. Further, in the under-baking area E12 that is less than the minimum baking temperature or less than the minimum baking time outside the proper baking area E10, the curing of the paint is in an incomplete state.

  The reference baking completion curve L is a curve depicting the reference baking completion points P1 to P8 indicating the standard of baking completion, and is drawn in advance in the proper baking area E10. And the baking setting part 1c calculates the baking completion value A corresponding to the polymerization value of the paint at each of the reference baking completion points P1 to P8. This baking completion value A is a value obtained by multiplying the rising temperature (° C.) by the baking time (minutes). The rising temperature (° C.) is a temperature difference from the lowest baking temperature to the baking temperature at the reference baking completion points P1 to P8. The baking time is a time required to reach the reference baking completion points P1 to P8. When the baking finish value A is greater than or equal to this, it can be considered that the baking of the paint has been completed.

  For example, the baking completion value A at the reference baking completion point P8 (165 ° C.) is 455 when the rising temperature is 35 ° C. and the baking time is 13 minutes. Similarly, the baking completion values A of the reference baking completion points P7 to P1 are 600, 625, 600, 525, 400, 215, and 50, respectively. However, the rising temperature with respect to the minimum baking temperature of 130 ° C. at the reference baking completion point P1 (130 ° C.) is 0 ° C., but the rising temperature is 1 ° C. as an exception at the minimum baking temperature of 130 ° C. If the minimum baking temperature is 130 ° C., 129 ° C. which is lower by 1 ° C. may be set as the minimum baking temperature, and all the rising temperatures may be calculated. The baking completion value A calculated in this way becomes a curve L1 having a baking temperature dependency (the baking temperature dependency of the baking completion value) as shown in FIG.

  Further, the baking setting unit 1c introduces the concept of the baking time weight coefficient value B for each baking temperature according to the target baking temperature in order to perform the baking time correction or the superposition value correction for different baking temperatures. For example, when the target baking temperature is 155 ° C., the baking time weight coefficient value B of the reference baking completion point P8 (165 ° C.) is set to the baking completion value (625) of the target baking temperature up to the reference baking completion point P8. A value obtained by dividing the baking time by 13 minutes (= 625/25) = 48. Similarly, the printing time weighting coefficient values B of the reference printing completion points P7 to P1 are 31, 2520, 17, 15, 14, and 12, respectively. The baking time weighting coefficient value B corresponding to the target baking temperature calculated in this manner is a curve having a baking temperature dependency (the baking temperature dependency of the baking time weighting coefficient value) L2 as shown in FIG.

  Note that the above-described reference baking completion curve L, the baking temperature dependency L1 of the baking completion value, and the baking temperature dependency L2 of the baking time weight coefficient value are held as the baking information D3 in the storage unit 5. In the baking information 3, a preset target baking temperature Ta is held.

(Baking control process by the control unit)
Next, with reference to the flowchart shown in FIG. 5, a printing control processing procedure by the control unit 1 will be described. As shown in FIG. 5, first, the printing setting unit 1c sets the above-described printing information (step S101). That is, the reference baking completion curve L, the baking temperature dependency L1 of the baking completion value, the baking temperature dependency L2 of the baking time weighting coefficient value, and the target baking temperature Ta are set. Thereafter, the baking control unit 1d repeatedly moves on the three-dimensional movement path RT while performing the position control and the energization control of the induction heating coil 3 so that the workpiece 10 reaches the target baking temperature Ta, and performs the baking process. Perform (step S102).

  The baking control unit 1d acquires the temperature distribution map D2 after the movement control is repeatedly performed on the three-dimensional movement route RT a predetermined number of times (step S103). Then, the variable N is set to an initial value 0 (step S104). Thereafter, one temperature mesh is acquired from the temperature distribution map D2 (step S105). Then, the baking control unit 1d determines whether or not the baking temperature T of the acquired temperature mesh is equal to or higher than the baking minimum temperature (for example, 130 ° C.) (step S106).

  When the baking temperature T is equal to or higher than the baking minimum temperature (for example, 130 ° C.) (step S106, Yes), the integrated polymerization value is calculated (step S107), and the process proceeds to step S109. The integrated polymerization value is a value obtained by multiplying the difference baking time Δt between the previous baking temperature and the current baking temperature, which is equal to or higher than the lowest baking temperature, by the baking time weight coefficient value B corresponding to the current baking temperature. For example, when the differential baking time Δt is 1 minute and the current baking temperature is 150 ° C., a value obtained by multiplying the differential baking time Δt = 1 minute by a baking time weight coefficient value B = 20 at a baking temperature of 150 ° C. = 20 Is the integrated polymerization value. On the other hand, when the baking temperature T is not equal to or higher than the lowest baking temperature (for example, 130 ° C.) (No at Step S106), the integrated polymerization value = 0 is set (Step S108), and the process proceeds to Step S109. In step S109, the cumulative polymerization value is added to the cumulative polymerization value held at the position corresponding to the acquired temperature mesh to update the cumulative polymerization value map D4.

  Thereafter, the variable N is incremented (step S110), and it is determined whether or not the variable N is equal to or greater than the number of temperature meshes M (step S111). That is, it is determined whether or not the processing for all temperature meshes on the temperature distribution map D2 has been completed. If the variable N is not equal to or greater than the number of temperature meshes M (step S111, No), the process proceeds to step S105, the next temperature mesh is selected and acquired, and the processes of steps S106 to S110 described above are repeated. . On the other hand, when the variable N is equal to or greater than the number of temperature meshes M (step S111, Yes), the process proceeds to step S112.

  Thereafter, the baking control unit 1d determines whether or not the cumulative polymerization value of all the meshes in the cumulative polymerization value map D4 is equal to or higher than the baking completion value A1 with respect to the target baking temperature Ta (step S112). When the cumulative polymerization value of all meshes in the cumulative polymerization value map D4 is equal to or higher than the baking completion value A1 with respect to the target baking temperature Ta (step S112, Yes), it can be considered that all the paints are cured. The baking process by the induction heating coil 3 is finished (step S113), and this process is finished.

  On the other hand, if the cumulative polymerization value of all meshes in the cumulative polymerization value map D4 is not equal to or higher than the baking completion value A1 with respect to the target baking temperature Ta (No in step S112), the variable N is set to the initial value 0 ( Step S114). Furthermore, one temperature mesh is acquired from the temperature distribution map D2 (step S115). Then, the baking control unit 1d determines whether or not the acquired baking temperature T of the temperature mesh is lower than the target baking temperature Ta (step S116). And when the baking temperature T of the acquired temperature mesh is less than the target baking temperature Ta (step S116, Yes), the baking control unit 1d energizes the induction heating coil 3 at the three-dimensional position with respect to the temperature mesh position. Is set to increase (step S117), and the process proceeds to step S120.

  When the acquired temperature mesh baking temperature T is not lower than the target baking temperature Ta (step S116, No), the baking control unit 1d further determines whether or not the acquired temperature mesh baking temperature T exceeds the target baking temperature Ta. Is determined (step S118). When the acquired baking temperature T of the temperature mesh exceeds the target baking temperature Ta (step S118, Yes), the baking control unit 1d determines the amount of current to be supplied to the induction heating coil 3 at the three-dimensional position with respect to the temperature mesh position. Setting to decrease is performed (step S119), and the process proceeds to step S120. On the other hand, when the acquired baking temperature T of the temperature mesh does not exceed the target baking temperature Ta (No in step S118), the process proceeds to step S120.

  In step S120, the variable N is incremented. Thereafter, it is determined whether or not the variable N is equal to or greater than the number of temperature meshes M (step S121). That is, it is determined whether or not the processing for all temperature meshes on the temperature distribution map D2 has been completed. If the variable N is not equal to or greater than the number of temperature meshes M (step S121, No), the process proceeds to step S115, the next temperature mesh is selected and acquired, and the processes of steps S116 to S120 described above are repeated. . On the other hand, when the variable N is equal to or greater than the number of temperature meshes M (Yes in step S121), the process proceeds to step S102, and the above-described processing is repeated.

(Example of baking control)
The cumulative polymerization value map D4 is updated by the baking control unit 1d when the induction heating coil 3 is controlled to make one round of the three-dimensional movement path RT in one minute, and the baking temperature T is the first five minutes (5 cycles). The minimum baking temperature reaches 130 ° C. Since the previous baking temperature at this time is less than 130 ° C., the differential baking time Δt is 0, and the integrated polymerization value is 0. When the baking temperature T reaches 135 ° C. in 1 minute thereafter, the integrated polymerization value is obtained by multiplying the differential baking time Δt = 1 (min) by the baking time weight coefficient value B = 14 of the baking temperature 135 ° C. = 14 Thus, this integrated polymerization value = 14 is held and updated in the cumulative polymerization value map D4. Further, when the baking temperature T reaches 140 ° C. in the subsequent one minute, the integrated polymerization value is a value obtained by multiplying the differential baking time Δt = 1 (minutes) by the baking time weight coefficient value B = 15 at the baking temperature of 140 ° C. = 15, and the value obtained by adding the previous accumulated polymerization value = 14 to the accumulated polymerization value = 15 = 29 is retained and updated in the accumulated polymerization value map D4 as the current accumulated polymerization value = 29. Further, when the baking temperature T reaches 150 ° C. in the subsequent 1 minute, the integrated polymerization value is a value obtained by multiplying the differential baking time Δt = 1 (minutes) by the baking time weight coefficient value B = 20 at the baking temperature of 150 ° C. = 20, and the value obtained by adding the previous accumulated polymerization value = 29 to the accumulated polymerization value = 20 = 49 is retained and updated in the accumulated polymerization value map D4 as the current accumulated polymerization value = 49. Further, when the baking temperature T reaches 155 ° C. in the next one minute, the integrated polymerization value is a value obtained by multiplying the differential baking time Δt = 1 (min) by the baking time weighting coefficient value B = 25 at the baking temperature of 155 ° C. = 25, and the value obtained by adding the previous accumulated polymerization value = 49 to the accumulated polymerization value = 25 = 74 is held and updated in the accumulated polymerization value map D4 as the current accumulated polymerization value = 74.

  Here, since the baking temperature T has reached the target baking temperature Ta (= 155 ° C.), the baking controller 1d performs control to maintain the target baking temperature Ta. As described above, the cumulative polymerization degree map D4 is updated every minute. When 23 minutes have elapsed since the baking temperature T reached the target baking temperature Ta (= 155 ° C.), the integrated polymerization value is the same as the baking temperature T, so that the baking is performed at the differential baking time Δt = 23 (minutes). A value obtained by multiplying the baking time weighting coefficient value B = 25 at a temperature of 155 ° C. = 575, which is the same as this accumulated polymerization value = 575, and a value obtained by adding the previous accumulated polymerization value = 74 = 649 to the current accumulated polymerization value = 649 is stored and updated in the cumulative polymerization value map D4. At this time, since the cumulative polymerization value 649 is equal to or higher than the baking completion value A1 = 625 corresponding to the target baking temperature Ta (= 155 ° C.), the baking process is ended.

  In step S112, the case where the cumulative polymerization value of all the meshes in the cumulative polymerization value map D4 is not equal to or higher than the baking completion value A1 with respect to the target baking temperature Ta is, as shown in FIG. That is, the current accumulated polymerization value A of the mesh m41 is less than the baking completion value A1 with respect to the target baking temperature Ta. Further, in the setting process for increasing the amount of current to be supplied to the induction heating coil 3 in step S117, the baking temperature T of the mesh m21 is less than the target baking temperature Ta as shown in FIG. It is done when the state is. Further, in the setting process for reducing the amount of current to be supplied to the induction heating coil 3 in step S119, the temperature mesh in the temperature distribution map D2 is set to the target baking temperature Ta as shown in FIG. This is done when the condition is exceeded.

  The reference baking completion curve L described above is a value arbitrarily set in the proper baking area E10. However, as shown in FIG. 7, the reference baking completion curve L is in the appropriate baking area E10 for each baking temperature T. The proper baking area E10 is divided into an area E21 and an area E22 by a dividing curve L20 passing through the center of the baking time width of the area, and the divided area E21, E22 is set in the area E21 on the side where the baking time t is short. It is preferred that When the reference baking completion curve L is provided on the region E21 side, the baking completion time can be shortened, and in step S112, the cumulative polymerization values of all the meshes in the cumulative polymerization value map D4 are the baking completion values for the target baking temperature Ta. When it is determined that it is not equal to or higher than A1, there is a possibility that the entire baking time by the induction heating coil 3 may become long, but in this case as well, excessive baking of the paint can be prevented. The dividing curve L20 is not limited to a curve passing through the center of the baking time width, and the baking time width may be further divided to narrow the region E21 on the side where the baking time t is short.

  In steps S117 and S119, when the baking temperature T is less than the target baking temperature Ta or exceeds the target baking temperature Ta, the temperature of the partial region that is the mesh of the temperature distribution map D2 is controlled to the target baking temperature Ta. The current amount of the induction heating coil 3 has been increased or decreased. However, the present invention is not limited to this. The distance between the induction heating coil 3 and the object to be coated 10, the posture of the induction heating coil 3 with respect to the object to be coated 10, or the induction heating coil 3. The temperature of the object to be coated by the induction heating coil 3 may be controlled by controlling the partial movement speed. Further, temperature control is performed by appropriately combining the current amount of the induction heating coil 3, the distance between the induction heating coil 3 and the workpiece 10, the posture of the induction heating coil 3 with respect to the workpiece 10, and the partial moving speed of the induction heating coil 3. You may do it.

  Further, in the above-described embodiment, the reference baking completion curve L, the baking temperature dependency of the baking completion value A, and the baking temperature dependency of the baking time weight coefficient value B are the lowest baking temperature and the baking in the proper baking region E10. The explanation was given corresponding to the discrete baking temperature between the maximum temperatures. Not limited to this, the reference baking completion curve L, the baking temperature dependency of the baking completion value A, and the baking temperature dependency of the baking time weight coefficient value B may be controlled as a continuous function. Further, it may be controlled by a larger number of discrete values.

  In the present embodiment, after the start of the baking process of the paint by the induction heating coil 3, even when the baking temperature T reaches the target baking temperature Ta, when the temperature reaches the baking minimum temperature in the proper baking area E10. Since the degree of baking is determined in consideration of the degree of polymerization of the paint, the resin-based paint that is cured by the polymerization reaction can be baked in a short time and wasteful heating can be reduced. Therefore, energy saving can be achieved.

DESCRIPTION OF SYMBOLS 1 Control part 1a Position detection part 1b Temperature detection part 1c Baking setting part 1d Baking 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-coated object 11 Floor 12 Conveyor 13 Ceiling A Baking completion value B Baking time weighting coefficient value D1 3D shape information D2 Temperature distribution map D3 Baking information D4 Cumulative polymerization value map E10 Proper baking area E11 Excess baking area E12 Baking insufficient area E21, E22 area L Standard baking completion curve L1 Baking temperature dependence of baking completion value L2 Baking temperature dependence of baking time weight coefficient value L20 Dividing curve m21, m22, m41 Mesh T Baking temperature Ta Target baking temperature RT 3D movement path

Claims (7)

A coating and drying apparatus for moving an induction heating coil around a workpiece and baking the paint applied to the workpiece,
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;
A reference baking completion curve is set in which the reference baking completion point is drawn in the appropriate baking area of the paint indicated by the baking temperature and baking time, and the baking time of the point on the reference baking completion curve and the appropriate baking area Generating and setting the baking temperature dependency of the baking completion value, which is a value obtained by multiplying the baking temperature of the point on the reference baking completion curve by the rising temperature from the baking minimum temperature of the above, and setting the target baking temperature, A baking setting unit that generates and sets a baking temperature dependency of a baking time weighting coefficient value that is a value obtained by dividing the baking completion value at the target baking temperature by the baking time to the reference baking completion point at each baking temperature; ,
After the start of baking using the induction heating coil, when the temperature detected by the temperature detection unit is equal to or higher than the minimum baking temperature, between the previous baking temperature that is higher than the minimum baking temperature and the current baking temperature. The cumulative polymerization value obtained by multiplying the cumulative baking value corresponding to the current baking temperature by the differential baking time for the current baking temperature and the cumulative polymerization value obtained up to the previous time is cumulatively calculated as the current cumulative polymerization value. When the value exceeds the baking completion value for the target baking temperature, the baking control unit that performs control to end baking using the induction heating coil as the baking is completed;
A paint drying apparatus characterized by comprising:   The reference baking completion curve, the baking temperature dependency of the baking completion value, and the baking temperature dependency of the baking time weight coefficient value are discrete baking between the lowest baking temperature and the highest baking temperature in the proper baking region. The paint drying apparatus according to claim 1, wherein the paint drying apparatus is set corresponding to a temperature. The temperature detection unit has a temperature distribution map corresponding to the three-dimensional position,
The baking control unit completes baking when the current accumulated polymerization value exceeds the baking completion value for the target baking temperature in all regions on the temperature distribution map, and If there is a partial area where the baking temperature is lower than the target baking temperature, the induction heating coil is controlled to raise the temperature relative to the partial area, and the current baking temperature is within the area on the temperature distribution map. 3. The coating drying apparatus according to claim 1, wherein when there is a partial region exceeding the baking temperature, the induction heating coil is controlled to lower the temperature with respect to the partial region.   The said drying control part controls the temperature with respect to the said partial region by increasing / decreasing the electric current amount of the said induction heating coil with respect to the said partial region, The coating drying apparatus of Claim 3 characterized by the above-mentioned.   The reference baking completion curve is obtained by dividing the appropriate baking area by a dividing curve that passes through the center of the baking time width in the appropriate baking area for each baking temperature, and among the divided areas, the baking time side is smaller. The paint drying apparatus according to claim 1, wherein the paint drying apparatus is set in an area.   The coating drying apparatus according to claim 1, wherein the target baking temperature is a temperature at which the baking completion value is maximized. A coating and drying method in which an induction heating coil is moved around the object to be coated, and the paint applied to the object to be coated is baked.
A reference baking completion curve is set in which the reference baking completion point is drawn in the appropriate baking area of the paint indicated by the baking temperature and baking time, and the baking time of the point on the reference baking completion curve and the appropriate baking area Generating and setting a baking completion value which is a value obtained by multiplying the baking temperature at the point on the reference baking completion curve by a rising temperature from the lowest baking temperature of the above, and setting a target baking temperature, and at the target baking temperature A baking setting step for generating and setting a baking time weighting factor value that is a value obtained by dividing the baking completion value by the baking time to the reference baking completion point at each baking temperature;
After the start of baking using the induction heating coil, a three-dimensional position that is a heating target position of the object to be coated by the induction heating coil is detected, and a temperature of the object to be coated corresponding to the detected three-dimensional position is detected. A temperature detection step;
When the temperature detected in the temperature detection step is equal to or higher than the minimum baking temperature, the current baking temperature corresponds to the differential baking time between the previous baking temperature and the current baking temperature that was higher than the minimum baking temperature. A cumulative value obtained by multiplying the cumulative polymerization value multiplied by the baking time weighting factor value is added to the previous cumulative polymerization value as a current cumulative polymerization value, and the current cumulative polymerization value is used as a baking completion value for the target baking temperature. When exceeding, a baking control step for performing control to end baking using the induction heating coil as baking is completed;
A coating drying method characterized by comprising:

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