JP2015140989A - Coating and drying device and coating and drying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep surface temperature of a coated object uniform by a simple configuration even if the coated object has a complex shape.SOLUTION: This invention comprises a temperature distribution acquisition part 2 for acquiring temperature distribution information D2 of a coated object 10; an induction heating part 4 for induction heating the coated object 10 while an induction heating coil 3 is being electrically conductive and moved; and a control part 1 for repeatedly moving the induction heating coil 3 on a three-dimensional moving passage RT and drying coating material by induction heating on the basis of a three-dimensional shape information D1 and a temperature distribution information D2. When a difference between the maximum temperature and the minimum temperature in the temperature distribution indicated by the temperature distribution information D2 acquired in sequence exceeds a prescribed range, the control part 1 performs control over at least one of an attitude changing of the induction heating coil 3, a partial passage change of a three-dimensional moving passage RT, a partial passage adding, or a passage changing including a partial passage deletion on the basis of the three-dimensional shape information D1 and the temperature distribution information D2.

Description

  The present invention relates to a coating drying apparatus and a coating drying method capable of making the surface temperature of a workpiece to be uniform with a simple configuration even if the workpiece 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.

  Moreover, in patent document 2, it is set as the movable type which couple | bonded the induction heating coil with the robot arm, and while detecting the degree of the heating of a to-be-heated body with a temperature sensor, at least output of an induction heating coil, heating time, or movement time A mobile induction heating system is described that controls one. Thus, in Patent Document 2, the heated body can be heated uniformly regardless of the shape or material of the heated body.

JP 2010-281490 A JP 2011-198730 A

  By the way, in Patent Document 2, the surface of the object to be coated is detected regardless of the shape of the object to be coated, and the output of the induction heating coil, the heating time, or the moving time is adjusted. However, in the apparatus of Patent Document 2, it is difficult to make the surface temperature uniform when the object to be coated has a complicated shape in the heating region of the induction heating coil.

  On the other hand, in Patent Document 1, a plurality of different induction heating coil molds are prepared, and the shape of the induction heating coil is selectively deformed using the plurality of induction heating coil molds according to the object to be coated. ing. Thereby, the apparatus of Patent Document 1 can make the surface temperature uniform even if the object to be coated has a complicated shape.

  However, in Patent Document 1, since it is necessary to prepare a plurality of different induction heating coil molds in advance, a variety of induction heating coil molds are prepared in order to cope with various shapes. It is necessary to keep. For this reason, the apparatus of patent document 1 becomes a complicated thing. On the other hand, when the number of different induction heating coils is small, the apparatus of Patent Document 2 lacks versatility for an object to be coated that includes various shapes.

  The present invention has been made in view of the above, and a coating drying apparatus and coating drying capable of uniformizing the surface temperature of an object to be coated with a simple configuration even if the object has a complicated shape. It aims to provide a method.

  In order to solve the above-described problems and achieve the object, a paint drying apparatus according to the present invention is a paint drying apparatus that dries a paint applied to an object to be coated by induction heating. A three-dimensional shape holding unit for holding three-dimensional shape information; a temperature distribution acquisition unit for acquiring temperature distribution information of the object to which the paint has been applied; and an induction heating coil at the tip to energize the induction heating coil The induction heating coil is repeatedly moved on the three-dimensional movement path with respect to the object to be coated based on the induction heating unit that moves the object to be coated by induction heating and the three-dimensional shape information and the temperature distribution information. And a controller for controlling the drying of the paint by induction heating, and the controller controls a difference between a maximum temperature and a minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information within a predetermined range. If it is determined, based on the three-dimensional shape information and the temperature distribution information acquired sequentially, the posture change of the induction heating coil, the partial path change of the three-dimensional movement path, the partial path addition, or the partial path Control of at least one of route change including deletion is performed.

  The paint drying apparatus according to the present invention is characterized in that, in the above invention, the route change of the three-dimensional movement route includes a change of a gap between the surface of the object to be coated and the induction heating coil. To do.

  In the paint drying apparatus according to the present invention as set forth in the invention described above, when the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, the control unit When the ratio of the temperature change of the temperature in the region exceeding the predetermined range to the temperature change of the average temperature in the distribution is lower than the predetermined value, and the portion is flat, the gap is changed to change the gap The portion is brought close to the average temperature.

  In the paint drying apparatus according to the present invention as set forth in the invention described above, when the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, the control unit If the ratio of the temperature change of the temperature in the region exceeding the predetermined range to the temperature change of the average temperature in the distribution is lower than the predetermined value, and the portion is not flat, the posture of the induction heating coil is changed. The portion is brought close to the average temperature.

  In the paint drying apparatus according to the present invention as set forth in the invention described above, when the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, the control unit When the ratio of the temperature change of the temperature in the region exceeding the predetermined range to the temperature change of the average temperature in the distribution exceeds a predetermined value, and the temperature of the part is lower than the average temperature In addition, the three-dimensional movement path of the induction heating coil adds a partial path or changes a partial path through the part to bring the part close to the average temperature.

  In the paint drying apparatus according to the present invention as set forth in the invention described above, when the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, the control unit When the ratio of the temperature change of the temperature in the region exceeding the predetermined range to the temperature change of the average temperature in the distribution exceeds a predetermined value, and the temperature of the part is higher than the average temperature In addition, the three-dimensional movement path of the induction heating coil is partly changed so as to avoid the part, and the part is brought close to the average temperature.

  In the paint drying apparatus according to the present invention as set forth in the invention described above, the control unit is configured such that after the average temperature in the temperature distribution reaches the target temperature, the maximum temperature of the temperature distribution indicated by the temperature distribution information sequentially acquired. If the difference between the temperature and the minimum temperature exceeds a predetermined range, and there is a continuous temperature non-uniform portion, a part of the three-dimensional movement path for the same temperature non-uniform portion is deleted. It is characterized by that.

  Further, in the paint drying apparatus according to the present invention, in the above invention, when the posture change or path change of the induction heating coil is performed, the control unit changes the posture change or path change of the induction heating coil. Until it is performed, induction heating is performed with the changed three-dimensional movement path and posture.

  The paint drying apparatus according to the present invention is characterized in that, in the above-mentioned invention, the three-dimensional movement path preferentially heats a portion having a large heat capacity.

  According to another aspect of the present invention, there is provided a coating drying method for drying a coating applied to an object by induction heating, a three-dimensional shape holding step for holding three-dimensional shape information of the object to be coated; And a temperature distribution acquisition step of acquiring temperature distribution information of the object to which the paint is applied, and guidance on a three-dimensional movement path for the object based on the three-dimensional shape information and the temperature distribution information. A control step of repeatedly moving the heating coil to dry the paint by induction heating, and the control step includes a difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information. Is over a predetermined range, based on the three-dimensional shape information and the temperature distribution information acquired sequentially, the posture change of the induction heating coil and the three-dimensional movement path Some rerouting and performing at least one of control of a part route addition, or rerouting including a partial path deletion.

  According to the present invention, when the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds the predetermined range, the control unit includes the three-dimensional shape information and the sequentially acquired temperature distribution information. Based on the above, at least one of the posture change of the induction heating coil and the route change including the partial route change of the three-dimensional movement route, the partial route addition, or the partial route deletion is performed. As a result, the surface temperature of the object to be coated can be made uniform with a simple configuration even if the object has a complicated shape.

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 flowchart showing a paint drying processing procedure by the control unit. FIG. 3 is a schematic diagram showing the existence state of the maximum temperature and the minimum temperature in the induction heating region in the moving path along which the induction heating coil moves. FIG. 4 is a diagram showing the change over time of the in-plane average temperature. FIG. 5 is a flowchart showing a detailed processing procedure of the induction heating correction process shown in FIG. FIG. 6 is a diagram showing the gap dependency of the heat input rate showing an example of the contents held in the coil gap / heat input rate library. FIG. 7 is a diagram illustrating the coil posture dependency of the heat input rate showing an example of the contents held in the coil posture library. FIG. 8 is a diagram illustrating an example of a posture change of the induction heating coil. FIG. 9 is a schematic diagram showing a case where a spot-like protrusion exists outside the center line of the previous movement path. FIG. 10 is a schematic diagram illustrating a case where the line-shaped protrusion exists outside the center line of the previous movement path. FIG. 11 is a diagram illustrating an example of a route change in the case where a spot-like hole exists outside the center line of the previous movement route. FIG. 12 is a diagram illustrating another example of the route change in the case where the spot-like hole is present away from the center line of the previous movement route. FIG. 13 is a diagram showing a convection state of the outside air when the object to be coated is flat and has a uniform temperature. FIG. 14 is a diagram showing a convection state of the outside air when the object to be coated in FIG. 13 has a step. FIG. 15 is a diagram showing a convection state of the outside air when a disturbance occurs in the vicinity of the object to be coated in FIG. FIG. 16 is a diagram showing a heat dissipation state from an object to be coated having a constant surface emissivity. FIG. 17 is a diagram illustrating a heat dissipation state from the object to be coated when a paint is partially applied to the object to be coated in FIG. 16. FIG. 18 is a diagram illustrating a heat dissipation state from the object to be coated when a folded portion is formed in part in the object to be coated of FIG. FIG. 19 is a diagram illustrating a surface temperature state in the case where a protrusion is present on a part of an object to be coated formed of the same material. FIG. 20 is a diagram showing a surface temperature state when the shape of the object to be coated is the same and the materials are different. FIG. 21 is a diagram illustrating a surface temperature state when the conveyor component is in contact with an object to be coated.

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

  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 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 this embodiment, the temperature distribution acquisition unit 2 is installed on the ceiling 13.

  The induction heating coil 3 is 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 temperature distribution information D2 described above, the storage unit 5 includes a coil gap / heat input coefficient library D3, a coil attitude library D4, a path change library D5, initial movement path / posture information D6, and a previous movement path / posture described later. Information D7 is held.

  The display unit 6 displays and outputs various information such as the three-dimensional shape information D1, the temperature distribution information D2, and the movement path of the induction heating coil 3. Note that the three-dimensional shape information D1, the temperature distribution information D2, and the movement path of the induction heating coil 3 can be overlapped and output at least under the control of the control unit 1.

  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 position and posture of the induction heating coil 3 in order to burn the paint applied to the object to be coated 10. Then, the object to be coated 10 is induction-heated.

  Particularly, when the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information D2 exceeds a predetermined range, the control unit 1 includes the three-dimensional shape information D1 and the sequentially acquired temperature distribution information D2. The control of at least one of the attitude change of the induction heating coil 3 and the path change including the partial path change, the partial path addition, or the partial path deletion of the three-dimensional movement path of the induction heating coil 3 is performed. As a result, the three-dimensional movement path of the induction heating coil 3 is sequentially corrected, and heating can be performed while the temperature distribution of the object to be coated 10 is made uniform. The route change of the three-dimensional movement route includes a change of the gap between the surface of the workpiece 10 and the induction heating coil 3.

(Paint drying process)
Next, with reference to the flowchart shown in FIG. 2, the coating drying processing procedure by the control unit 1 will be described. First, the control unit 1 determines whether or not an object 10 to be loaded is detected based on a sensor output from an object detection sensor (not shown) (step S101). If the object to be coated 10 is not detected (No at Step S101), this determination process is repeated.

  On the other hand, when the control unit 1 detects the object to be coated 10 (step S101, Yes), the control unit 1 controls the posture of the induction heating coil 3 on the initial movement route based on the initial movement route / posture information D6. The object to be coated 10 is induction-heated by moving once (step S102). The initial movement path / posture information D6 is obtained in advance, and is a standard three-dimensional movement of the induction heating coil 3 that can perform induction heating while equalizing the temperature of the same object to be coated 10 as the object to be coated 10. The route and posture are shown.

  The induction heating coil 3 basically has a high frequency current / voltage / frequency controlled so that a high frequency current having a constant current value flows or a constant power value, and the coil forming surface is made to face the surface of the object 10 to be coated. It is moved in parallel with the gap to the object 10 being fixed. Further, the moving path of the induction heating coil 3 is set in the order from the region having a large heat capacity to the 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. .

  Then, when one induction heating by step S102 is complete | finished, the control part 1 acquires the temperature distribution information D2 induction-heated at that time (step S103). Then, based on the acquired temperature distribution information D2, the control unit 1 determines whether or not the difference between the maximum temperature and the minimum temperature of the induction heating region is within a predetermined range, for example, ± 5 ° C. (Step S104). . For example, as shown in FIG. 3, the control unit 1 acquires the maximum temperature Tmax and the minimum temperature Tmin within the induction heating region of the moving path RT along which the induction heating coil 3 has moved, and the difference is within ± 5 ° C. Judge whether there is.

  Thereafter, when the difference between the maximum temperature and the minimum temperature of the induction heating region is within a predetermined range (step S104, Yes), the control unit 1 further sets the in-plane average temperature Tave, which is the average temperature of the induction heating region, as a target. It is determined whether or not the temperature Ts has been reached (step S105). Then, when the in-plane average temperature Tave has reached the target temperature Ts (step S105, Yes), as shown in FIG. 4, the target temperature Ts is held from the time t1 when the target temperature Ts is reached. It is determined whether or not the time tm has been exceeded (step S106). This holding time tm is the baking time of the paint.

  As shown in FIG. 4, the in-plane average temperature Tave reaches the target attainment temperature Ts at the time t1 from the start of induction heating, and then the baking time is secured at the holding time tm at the target attainment temperature Ts. In this embodiment, one induction heating time is about 10 seconds, and the time from the induction heating start to the time point t1 is, for example, 20 minutes. The holding time tm is, for example, 20 minutes.

  Thereafter, when the holding time tm of the target temperature Ts is exceeded (Yes in step S106), the control unit 1 sends an instruction to carry out the object 10 to a control unit (not shown) of the conveyor 12, and the object 10 is Unload (Step S107). Thereafter, the control unit 1 determines whether or not there is an instruction to end this induction heating process (step S108). When there is no instruction to end (No at step S108), the process proceeds to step S101 and when there is an instruction to end. (Step S108, Yes), this processing is terminated.

  On the other hand, if the difference between the maximum temperature and the minimum temperature of the induction heating region is not within the predetermined range (step S104, No), the control unit 1 performs induction heating correction processing described later to change the route of the three-dimensional movement route, The posture of the induction heating coil 3 is changed (step S109). The information corrected by the induction heating correction process is held as the previous movement route / posture information D7 and is sequentially updated.

  Thereafter, the control unit 1 performs induction heating once with the changed movement path or the changed posture of the induction heating coil 3 (step S110), and proceeds to step S103.

  If the in-plane average temperature Tave has not reached the target attainment temperature Ts (step S105, No), or if the in-plane average temperature Tave has not exceeded the holding time tm of the target attainment temperature Ts (step S106, No), the control unit 1 Then, using the previous movement path / posture information D7, induction heating is performed once with the currently set movement path and the posture of the induction heating coil 3 (step S111), and the process proceeds to step S103. Note that the initial movement route / posture information D6 is held as a default in the previous movement route / posture information D7.

(Induction heating correction processing)
Next, details of the induction heating correction processing procedure by the control unit 1 will be described with reference to the flowchart shown in FIG. First, the control unit 1 specifies a temperature non-uniform location based on the temperature distribution information D2 (step S201). This temperature non-uniform location is specified when the difference between the in-plane average temperature Tave and the temperature of the temperature non-uniform location candidate region exceeds a predetermined temperature, the temperature non-uniform location candidate region is defined as a temperature non-uniform location. Then, the coordinates of the identified temperature nonuniformity are acquired. The predetermined temperature is, for example, ± 5 ° C. As described above, the control unit 1 associates the three-dimensional position information of the three-dimensional shape information D1, the temperature distribution information D2, and the three-dimensional movement path of the induction heating coil 3 with each other.

  Thereafter, one temperature non-uniform location is selected (step S202). Further, after the in-plane average temperature Tave has reached the target attainment temperature Ts, it is determined whether or not the same temperature non-uniform portion has continuously exceeded (target attainment temperature Ts × 1.05) (step S203). When the same temperature non-uniform place continuously exceeds (target reached temperature Ts × 1.05) (step S203, Yes), the movement path of this temperature non-uniform place is deleted (step S216). This partial path deletion process is performed when the heat capacity of the non-uniform temperature part is large and the temperature non-uniform part is rising even after the other region reaches the target temperature Ts. The partial path deletion may be performed substantially by deleting the current application to the induction heating coil 3.

  On the other hand, when the same temperature non-uniform location does not continuously exceed (target reached temperature Ts × 1.05) (step S203, No), it is further determined whether the heat input response rate is less than 50%. Judgment is made (step S204). This heat input response rate indicates the ratio of the temperature change at the temperature non-uniform portion with respect to the temperature change of the in-plane average temperature Tave. Specifically, first, a value obtained by subtracting the previous in-plane average temperature Tave0 from the current in-plane average temperature Tave1 is obtained as the standard heat input. Furthermore, a value obtained by subtracting the temperature of the previous temperature non-uniformity location at the same position from the temperature of the current temperature non-uniformity location is obtained as the temperature non-uniformity location heat input. Then, a value obtained by dividing the heat input at the non-uniform temperature by the standard heat input is converted into a percentage to obtain the heat input response rate.

  When the heat input response rate is not less than 50% (step S204, No), that is, when the temperature change response of the temperature nonuniformity is fast, the shape of the temperature nonuniformity is further flat or complicated (not flat). Is determined (step S205). This determination process is determined with reference to the three-dimensional shape information D1 of the non-uniform temperature portion. Here, the complicated shape includes an uneven shape, an L shape, a U shape, a curved shape, and the like.

  When the shape of the non-uniform temperature portion is flat (step S204, flat), the coil gap / heat input coefficient library D3 is read (step S206). And the control part 1 performs the path | route change which is the gap change of the induction heating coil 3 with reference to the coil gap and heat input rate library D3 (step S207). In the coil gap / heat input coefficient library D3, for example, information on the gap dependency of the heat input coefficient shown in FIG. 6 is held. Regarding the gap dependency of the heat input rate, when the gap d is widened, the heat input rate decreases and the induction heating amount decreases, and when the gap d is narrowed, the heat input rate increases and the induction heating amount increases. Therefore, when the temperature at the non-uniform temperature is lower than the in-plane average temperature Tave, the gap is changed to narrow the gap d. On the other hand, when the temperature of the non-uniform temperature portion is higher than the in-plane average temperature Tave, the gap is changed to widen the gap d.

  On the other hand, when the shape of the temperature nonuniformity is not flat and complicated (step S204, complicated), the coil posture library D4 is read (step S208). And the control part 1 changes the attitude | position of the induction heating coil 3 with reference to the coil attitude | position library D4 (step S209). In the coil posture library D4, for example, information on the coil posture dependency of the heat input rate shown in FIG. 7 is held. When the induction heating coil 3 is tilted with respect to the surface of the article 20 to be coated, the heat input rate at the position where the gap is narrowed increases and the gap is widened. The heat input at is reduced. Therefore, as shown in FIG. 8, when the recess 20a is smaller than that of the induction heating coil 3, if the induction heating coil 3 is changed to a posture in which the induction heating coil 3 is inclined toward the recess 20a, the temperature rise of the complex shape region having the recess 20a Can be corrected to be uniform. In addition, when it has a convex part in a temperature nonuniform location, it changes to the attitude | position which widens the gap of the position of a convex part and narrows the gap of the part which is not a convex part.

  On the other hand, when the heat input response rate is less than 50% (step S204, Yes), that is, when the temperature change response of the temperature nonuniformity is slow, the shape of the temperature nonuniformity is a spot shape or a line shape. It is determined whether or not there is (step S210). Thereafter, when the shape of the non-uniform temperature portion is a spot shape (step S210, spot shape), it is determined whether or not the non-uniform temperature portion is a hole (step S211). If the shape of the non-uniform temperature portion is a line (step S210, line shape), it is determined whether the shape of the non-uniform temperature portion is a hole (step S212). The determination processing in steps S210, S211, and S212 is determined with reference to the three-dimensional shape information D1 of the temperature non-uniform location as in step S205.

If the shape of the non-uniform temperature portion is not a hole (steps S211, S212: No), a partial path is added to the movement path of the induction heating coil 3 (step S213). For example, as shown in FIG. 9, when the spot-like projection 21 exists outside the center line of the previous movement path RTa, the region of the projection 21 becomes a portion having uneven temperature due to an increase in heat capacity. In this case, a movement path for moving to the protrusion 21 is added after the movement of the previous movement path RTa is completed.
In this case, the induction heating coil 3 statically heats the region of the protrusion 21 in a spot shape.

  Further, as shown in FIG. 10, when the line-shaped protrusion 22 is present away from the center line of the previous movement path RTa, the region of the protrusion 22 becomes a heat non-uniform portion due to an increased heat capacity. In this case, after the movement of the previous movement route RTa is completed, a movement route RTb passing through the protrusion 22 is added. In this case, the induction heating coil 3 moves and heats the region of the protrusion 22 in a line shape.

  On the other hand, when the shape of the non-uniform temperature portion is a hole (steps S211, S212: Yes), the coil posture library D4 or the path change library D5 is read (step S214). Thereafter, the control unit 1 performs a partial path change on the movement path of the induction heating coil 3 (step S215). For example, as shown in FIG. 11, when the spot-like hole 31 is present out of the center line of the previous movement path RTa, the peripheral edge E31 of this hole 31 is because the eddy current path concentrates on the edge of the hole. It becomes an overheated state and becomes a temperature non-uniform location. In this case, the route change is performed by shifting the center line of the movement route RTa to the opposite side of the hole 31 with reference to the route change library D5 so that the previous movement route RTa does not pass through the hole 31.

  Alternatively, as shown in FIG. 12, the control unit 1 tilts the induction heating coil 3 so as to increase the gap between the holes 31 and changes the posture of the induction heating coil 3 to increase the gap at the center position. As a result, the route may be changed. This change process is effective when the moving path of the induction heating coil 3 cannot be changed along the surface to be coated as shown in FIG.

  11 and 12 describe the spot-like hole 31, but when a line-like hole corresponding to FIG. 10 exists, the same route change as the hole 31 may be performed.

  Note that the route change may be performed in the same manner as in step S215 instead of the route addition in step S213. For example, when the protrusions 21 and 22 shown in FIGS. 9 and 10 exist, the path is changed to the path passing through the protrusions 21 and 22, contrary to the path change shown in FIG. 11. In the case of the path change corresponding to FIG. 12, in contrast to the path change shown in FIG. 12, three-dimensional by the attitude change that tilts the induction heating coil 3 so that the gaps on the projections 21 and 22 side become smaller. Change part of the travel route. In this case, similarly to step S214, a process of reading the coil posture library D4 or the path change library D5 is performed before the path is changed.

  The results of the route change, posture change, route addition, and route deletion in steps S207, S209, S213, S215, and S216 described above are updated as the previous movement route / posture information D7. In addition, after the above-described steps S207, S209, S213, S215, and S216, the process proceeds to step S217. In step S217, it is determined whether or not there are other temperature non-uniform portions. If there are other temperature non-uniform portions (step S217, Yes), the process proceeds to step S202, where other temperature non-uniform portions exist. If not (No at Step S217), the process returns to Step S109.

  In steps S211, S212, it is determined whether or not the hole is a hole. However, the same processing is performed even for a recess close to the hole structure.

(Heat dissipation of the object to be painted)
Here, the heat dissipation of the object to be coated will be described. First, as shown in FIG. 13, when the paint 42 is applied on the object 41 extending in the vertical direction, and the object 41 is at a uniform temperature, the convection of the outside air extends vertically upward. Laminar flow and uniform heat dissipation. Here, as shown in FIG. 14, when there is a step 51, turbulent flow is generated at the step 51. As a result, the amount of heat released from the step 51 increases, and the object to be coated 41 does not reach a uniform temperature. As shown in FIG. 15, even if the step 51 shown in FIG. 14 does not exist, if a disturbance 52 occurs, the laminar flow collapses. And a turbulent flow generate | occur | produces in the part which the laminar flow collapsed, the heat dissipation of this part increases, and the to-be-coated object 41 does not become uniform temperature.

  Moreover, as shown in FIG. 16, in the case of the to-be-coated object 41 having a constant surface emissivity, a constant heat radiation is performed. On the other hand, as shown in FIG. 17, when the paint 42 is partially applied, the amount of heat released from the paint 42 is larger than the amount of heat released from the metal surface to which the paint 42 is not applied. As shown in FIG. 18, when the folded portion 53 is formed in a part, heat radiation and radiation are repeated inside the folded portion 53, so that the heat radiation from the folded portion 53 is reduced.

  Further, as shown in FIG. 19, even if the object 41 is the same material, the heat capacity increases in the portion where the protrusion 61 exists. For this reason, even if uniform heat input is performed on the entire object 41, the temperature Tb is lower than the ambient temperature Ta at the portion where the protrusion 61 exists. Moreover, as shown in FIG. 20, even if the shapes of the articles 41a and 41b are the same, if the materials are different, the heat capacities are different. For this reason, even if uniform heat input is performed on the entire objects to be coated 41a and 41b, the heating rates of the objects to be coated 41a and 41b are different. Furthermore, as shown in FIG. 21, even when the conveyor part 62 is simply in contact with the object 41, heat is transferred and the heat is dissipated from the object 41 to the conveyor part 62 side. . As a result, the temperature Tb of the portion where the conveyor part 62 contacts is lower than the ambient temperature Ta.

  In this way, even if the object to be coated is formed of the same shape and the same material, there is a difference in heat dissipation due to various factors, even if uniform heat input is performed on the object to be coated. The temperature is not uniform.

  In this embodiment, it is possible to cope with the above-described diversity of heat dissipation of the object to be coated by changing the path or posture of the three-dimensional movement path of the induction heating coil 3. Therefore, since it is not necessary to prepare various induction heating coils, the surface temperature of the object to be coated can be uniformly controlled with a simple configuration.

  In the above-described embodiment, one induction heating coil 3 and one temperature distribution acquisition unit 2 are provided. However, the present invention is not limited to this, and a plurality of induction heating coils 3 may be provided. A plurality of temperature distribution acquisition units 2 may be provided. In this case, it is preferable that the induction heating coils 3 and the temperature distribution acquisition units 2 are paired. Moreover, when providing the several induction heating coil 3, it is preferable to divide | segment the induction heating area | region with respect to one to-be-coated article 10 into an induction heating area | region. In addition, you may set a guidance division | segmentation area | region overlappingly, respectively. Moreover, the several induction heating coil 3 may overlap and heat the divided | segmented induction heating area | region.

  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. In this case, it is necessary to hold a coil gap / heat input coefficient library D3, a coil posture library D4, and a path change library D5 corresponding to the induction heating coil 3 to be used.

DESCRIPTION OF SYMBOLS 1 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 10,20,41,41a, 41b To-be-coated object 11 Floor 12 Conveyor 13 Ceiling 20a Recessed part 21,22,61 Protrusion 31 Hole 42 Paint 51 Step 52 Disturbance 53 Turn-up part 62 Conveyor parts d Gap D1 3D shape information D2 Temperature distribution information D3 Coil gap / heat input coefficient library D4 Coil attitude library D5 Path change library D6 Initial movement path / attitude information D7 Previous movement route / posture information

Claims (10)

A paint drying apparatus for drying a paint applied to an object by induction heating,
A three-dimensional shape holding unit for holding three-dimensional shape information of the object to be coated;
A temperature distribution acquisition unit that acquires temperature distribution information of the object to which the paint is applied;
An induction heating unit that has an induction heating coil at the tip and that is heated while energizing the induction heating coil to inductively heat the object to be coated;
Based on the three-dimensional shape information and the temperature distribution information, a control unit that performs control to repeatedly move the induction heating coil on a three-dimensional movement path with respect to the object to be coated and dry the paint by induction heating;
With
The control unit, when the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, based on the three-dimensional shape information and the temperature distribution information sequentially acquired, A paint drying apparatus that controls at least one of a posture change of the induction heating coil and a route change including a partial route change, a partial route addition, or a partial route deletion of the three-dimensional movement route. .   The paint drying apparatus according to claim 1, wherein the route change of the three-dimensional movement route includes a change of a gap between a surface of the object to be coated and the induction heating coil.   When the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, the control unit is in a region exceeding the predetermined range with respect to the temperature change of the average temperature in the temperature distribution. 3. The part according to claim 2, wherein when the ratio of the temperature change of the temperature is lower than a predetermined value and the part is flat, the gap is changed to bring the part closer to the average temperature. The coating drying apparatus described.   When the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, the control unit is in a region exceeding the predetermined range with respect to the temperature change of the average temperature in the temperature distribution. The ratio of the temperature change of temperature is a portion lower than a predetermined value, and when the portion is not flat, the posture of the induction heating coil is changed to bring the portion closer to the average temperature. The coating drying apparatus as described in any one of 1-3.   When the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, the control unit is in a region exceeding the predetermined range with respect to the temperature change of the average temperature in the temperature distribution. When the ratio of the temperature change of the temperature exceeds a predetermined value and the temperature of the portion is lower than the average temperature, the three-dimensional movement path of the induction heating coil passes through the portion. The paint drying apparatus according to any one of claims 1 to 4, wherein a part of the route is added or a part of the route is changed to bring the part close to the average temperature.   When the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the sequentially acquired temperature distribution information exceeds a predetermined range, the control unit is in a region exceeding the predetermined range with respect to the temperature change of the average temperature in the temperature distribution. When the temperature change ratio exceeds a predetermined value and the temperature of the portion is higher than the average temperature, the three-dimensional movement path of the induction heating coil avoids the portion. 6. The coating drying apparatus according to claim 1, wherein a part of the path is changed to bring the part close to the average temperature.   The control unit is a case where the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the temperature distribution information sequentially acquired after the average temperature in the temperature distribution reaches the target reached temperature exceeds a predetermined range, The partial path of the three-dimensional movement path with respect to the same temperature non-uniform part is deleted when the same temperature non-uniform part exists continuously. The coating drying apparatus described.   When the posture change or the path change of the induction heating coil is performed, the control unit uses the changed three-dimensional movement path and posture until the posture change or the path change of the next induction heating coil is performed. Induction heating is performed, The coating drying apparatus as described in any one of Claims 1-7 characterized by the above-mentioned.   The paint drying apparatus according to any one of claims 1 to 8, wherein the three-dimensional movement path preferentially performs induction heating on a portion having a large heat capacity. A paint drying method for drying a paint applied to an object by induction heating,
A three-dimensional shape holding step for holding three-dimensional shape information of the object to be coated;
A temperature distribution acquisition step of acquiring temperature distribution information of the object to be coated with the paint;
A control step of controlling the drying of the paint by induction heating by repeatedly moving an induction heating coil on a three-dimensional movement path for the object to be coated based on the three-dimensional shape information and the temperature distribution information;
Including
When the difference between the maximum temperature and the minimum temperature of the temperature distribution indicated by the temperature distribution information sequentially acquired exceeds a predetermined range, the control step is based on the three-dimensional shape information and the temperature distribution information sequentially acquired. A paint drying method comprising controlling at least one of a posture change of the induction heating coil and a route change including a partial route change, a partial route addition, or a partial route deletion of the three-dimensional movement route. .

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