JP4746949B2 - Prediction method of air pool occurrence - Google Patents

Description

  The present invention relates to an air pool generation prediction method, and more particularly to an air pool and a liquid pool prediction method when a plurality of overlapping members are immersed in a liquid tank.

  Electrodeposition coating performed by immersing the body of an automobile in an electrodeposition bath filled with an electrodeposition solution can form a coating film substantially uniformly, and also coats the welded portion of the electrodeposited object There are advantages such as being able to. On the other hand, there is a drawback that air pockets called air pockets are generated in the recesses such as the hood inner surface, roof inner surface and floor lower surface of the vehicle body, and a coating film cannot be formed on the portions where the air pockets are generated.

  Therefore, conventionally, after the surface of the three-dimensional data of the work is divided into an arbitrary number of triangular polygons based on the vertex coordinate data, it can become an air pocket when the work is simulated and immersed in the electrodeposition tank in the posture of the tank entrance angle. By determining whether or not there is a surface portion, it is predicted whether or not air accumulation will occur (see, for example, Patent Document 1).

Further, as another method, there is a method in which the element adjacent to the end or hole of the workpiece is set as the electrodeposition liquid after dividing the three-dimensional data of the workpiece into a plurality of elements.
JP 2000-051750 A

  As shown in FIG. 13, according to the method of setting the element adjacent to the end or hole of the analysis target (work) as the electrodeposition liquid after dividing the three-dimensional data of the analysis target (work) into a plurality of elements. When the member V and the member W are laminated | stacked, the member V and the member W will perform judgment separately, respectively. In that case, when the hole is not provided in the member W located below the gravity direction of the member V, all the portions higher in the gravity direction than the dotted lines of the member V and the member W shown in FIG. This determination is almost the same as the case of actual electrodeposition coating.

  On the other hand, as shown in FIG. 3, when the member X and the member Y are laminated and the hole Y is provided in the member Y, the same method is used. Are all determined to be air in the gravitational direction from the dotted line shown in FIG. On the other hand, it is determined that the part of the member Y lower than the hole Z in the direction of gravity is immersed in the electrodeposition liquid, and it is determined that no air pool is generated.

  However, when the electrodeposition coating is actually performed in such a state, the air that should be pushed upward from the hole Z exists in the upper part of the member X, so that the air accumulates below the member Y. . Therefore, as shown in FIG. 16, the member Y also has an air reservoir in a range above the dotted line indicating the lowermost portion in the gravity direction of the air reservoir generated in the member X. Therefore, the conventional method cannot always make an accurate determination when the members are stacked.

  It is an object of the present invention to determine whether or not air accumulation occurs in each member constituting an object during electrodeposition coating when electrodeposition coating is performed on an object to be coated consisting of a plurality of laminated members. It is to accurately predict the position.

  In order to solve the above-described problem, the air pool occurrence prediction method according to claim 1 is an air pool occurrence prediction method for predicting an air pool in immersion coating of an object to be coated composed of a plurality of laminated members by simulation. , An element division step of dividing the image data of the object to be coated on which the plurality of members are stacked into a plurality of elements for each member, and among the plurality of members, determine the stacking order in the gravity direction at the time of dip coating, An analysis step for analyzing and predicting an air reservoir occurrence part based on an analysis result of a member having an upper stacking order is provided.

  According to a second aspect of the present invention, in the method of predicting the occurrence of air accumulation according to the first aspect, the analysis step includes an element and / or a hole adjacent to an end of a member among the elements divided in the element division step. A first step in which an element adjacent to the part is an initial boundary element; a second step in which attribute information of the initial boundary element is determined to be liquid; and attribute information of other elements is set to gas; and the initial step A third step of comparing the heights of the elements in order from the element adjacent to the boundary element and determining the attribute information as liquid or air, and the element whose attribute information has been determined after the element comparison has been completed A fourth step of determining that there is an air reservoir, and the second step is when the position of the initial boundary element is an air reservoir portion of a member above the member, Attribute information In the third step, the height of the adjacent element is compared with the height of the immersion tank liquid level between the element whose attribute information is determined to be liquid and the adjacent element. If the attribute information is higher than the height of the element determined to be liquid, the attribute information of the adjacent element is determined to be air, and if the attribute information is the same as or lower than the height of the element determined to be liquid, the adjacent It is characterized in that the attribute information of the element to be determined is liquid.

  According to a third aspect of the present invention, in the air pocket occurrence prediction method according to the second aspect, the heights of the barycentric coordinates of the respective elements are compared.

  According to the present invention, the laminated members are analyzed in the order in which they are higher in the direction of gravity, and the subsequent members are analyzed using the analysis results of the previously analyzed members. It is possible to predict the air pool and the generation position of the entire member. In addition, since it is possible to accurately analyze whether or not air accumulation occurs in an object to be coated in which a plurality of members are laminated, if an analysis result indicating that air accumulation occurs is obtained, the object to be painted is perforated. By changing the model to a model that has undergone a shape change and performing the analysis again, it is possible to predict the shape of the object to be coated in which no air accumulation occurs and promptly feed back to the object design. Thereby, the cost and schedule required for the development of the object to be coated can be shortened.

  Next, a first embodiment will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. In the following, a case where electrodeposition coating is performed on a vehicle body will be described as an example. However, a coating method to which the present invention can be applied is not limited to electrodeposition coating, and an object to be coated is a liquid paint. Any coating method may be used as long as it is immersed in the coating method. In the present embodiment, the finite element method is used and an example in which two members are stacked is described. However, the invention according to the present embodiment has two members stacked. The present invention is not limited to a certain case, and can be applied even to a portion where a plurality of members are laminated.

  FIG. 1 is a block diagram showing an embodiment of a fluid analyzing apparatus 1 for executing the air pool occurrence prediction method for the object to be coated.

  As shown in FIG. 1, the fluid analysis apparatus 1 of the present embodiment includes a CPU 2, a control unit 5 including a ROM 3 and a RAM 4 as storage areas, a keyboard 6, a keyboard controller 9 that controls the keyboard 6, and a display unit. For connection to the network 15, the display controller 11 that controls the display 10, the hard disk drive (HDD) 12, the flexible disk drive (FDD) 13, the disk controller 14 that controls the HDD 12 and the FDD 13, and the network 15. The network interface controller 16 is connected to and communicable with each other via a system bus 19.

  The CPU 2 comprehensively controls each component connected to the system bus 19 by executing software stored in the ROM 3 or the hard disk drive 12 or software supplied from the flexible disk drive 13. That is, the CPU 2 reads out the processing program from the ROM 3, the hard disk drive 12, or the flexible disk drive 13 according to a predetermined processing sequence and executes it, thereby performing the operation of the method for predicting the occurrence of air stagnation in the object to be coated according to the present embodiment. Control to achieve it.

  The CPU 2 reads the data of the member to be analyzed from the hard disk drive 12 and divides the surface into a plurality of elements to construct a two-dimensional numerical calculation model for numerical calculation. Note that the numerical calculation model used in the present embodiment is not limited to the two-dimensional numerical calculation model, and a three-dimensional numerical calculation model may be used. In addition, as long as the shape of the element is three or more, any shape such as a triangular shape or a quadrangular shape may be used.

  Moreover, CPU2 judges the lamination | stacking order in a gravitational direction at the time of immersion coating among several members which comprise a to-be-coated object, and analyzes in order which exists in a high position.

  Further, the CPU 2 sets the attribute information of the elements other than the initial boundary element and the initial boundary element as air in the two-dimensional numerical calculation model of the member to be analyzed, and the elements other than the initial boundary element and the initial boundary element, that is, the attribute By comparing the heights of elements whose information has not been determined, the attribute information of elements whose attribute information has not been determined is determined. Further, the CPU 2 compares the heights of elements for which attribute information has been determined and elements for which attribute information has not been determined to determine attribute information for elements for which attribute information has not been determined.

  Further, the CPU 2 analyzes the presence / absence of an air reservoir portion of each member in accordance with the order determined by the stacking order, and predicts whether an air reservoir will eventually occur as an object to be coated.

  The ROM 3 as the storage area stores, for example, various programs for executing the invention according to the present embodiment, data to be analyzed, and the like.

  The RAM 4 functions as a main memory or work area for the CPU 2. The keyboard controller 9 controls an instruction input from the keyboard 6 or a pointing device (not shown). The display controller 11 controls display on the display 10. The disk controller 14 controls access to the hard disk drive 12 and the flexible disk drive 13 that store a boot program, various applications, editing files, user files, a network management program, a predetermined processing program in the present embodiment, and the like. The network interface controller 16 transmits and receives data to and from a device or system on the network 15 in both directions.

  The hard disk drive 12 stores data on the body of the body to be analyzed.

  In the following, the method for predicting the occurrence of air accumulation in the object to be coated according to the present embodiment will be described in detail with reference to the flowchart of FIG.

  First, the controller 5 constructs a two-dimensional numerical calculation model for numerical calculation by dividing the surfaces of the member X and the member Y into a plurality of elements as shown in FIG. 3 (step S1).

  Next, after setting all these elements to air as an initial state (step S2), the control unit 5 designates the direction of gravity in the numerical calculation model (step S3).

  That is, the step S2 is a fluid setting step, and the step S3 is an initial setting step. This state schematically represents a state in which the periphery of the member X and the member Y before the body body is immersed in the electrodeposition tank is filled with air.

  Next, it is determined which of the laminated members is at the highest position in the direction of gravity during dip coating (step S4).

  In step S4, first, as shown in the flowchart of FIG. 4, first, serial numbers are assigned to the nodes of the elements of each member (step S41). Next, the X coordinate value, the Y coordinate value, and the Z coordinate value for each node are specified, and the X coordinate value, Y of the node for each member is stored in the storage area of the control unit 5 as shown in FIGS. The coordinate value and the Z coordinate value are extracted and stored (step S42).

  And the range on each XY seat surface of the member X and the member Y is specified (step S43), and it is judged whether there exists the range which the member X and the member Y overlap on the XY seat surface (step S44). . If it is determined that there is no overlapping range (NO), the analysis is terminated (END). If it is determined that there is an overlapping range (YES), the highest Z coordinate value of the nodes of the member X and member Y belonging to the overlapping range is extracted as shown in FIG. 6, and then shown in FIG. In this way, the members having elements having a high Z coordinate value are arranged in order (step S45), and the order of analysis is determined (step S46). In this case, the analysis is performed in the order of members having nodes with high Z coordinate values, and in this embodiment, the member X is determined as the first analysis target.

  In this embodiment, there are two members X and Y as the analysis target, but the analysis order is determined by the same method even when there are three or more members as the analysis target. .

  Next, an analysis is performed as to whether or not air retention occurs in the member X (step S5). Specifically, as shown in the flowchart of FIG. 8, in step 1, an element adjacent to the end portion or the hole Z of the member X divided into the two-dimensional numerical calculation model is set as an initial boundary element (step S51). Further, the attribute information of elements other than the initial boundary element is set to air (step S52).

  Here, the initial boundary element is an element adjacent to the end of the member X and the hole Z, and the attribute information is determined to be liquid, and the adjacent means sharing a node.

  Next, the height in the Z direction of the center of gravity of each element whose attribute information adjacent to the initial boundary element is set to air, that is, the element whose attribute information is not determined, is compared (step S53). Then, it is determined that the electrodeposition liquid enters the element for which attribute information having a low position of the center of gravity point is not determined and pushes air to be filled with the electrodeposition liquid. On the other hand, it is determined that air remains in an element for which attribute information having a higher center of gravity position than the initial boundary element has not been determined (step S54). The determination is made because the specific gravity of the electrodeposition liquid is larger than the specific gravity of air.

  A method of comparing the initial boundary element and the element whose attribute information has not been determined will be specifically described. When the element C shown in FIGS. 9A and 9B is the initial boundary element and the element A sharing the node α is an element whose attribute information has not been determined, the height of the center of gravity of the initial boundary element C in the Z direction The height in the Z direction of the center of gravity of element A for which attribute information has not been determined is compared, and the height of the center of gravity of element A for which attribute information has not been determined is lower than the height of the center of gravity of initial boundary element C In this case, the attribute information of the element A whose attribute information is not determined is determined as the electrodeposition liquid. On the other hand, when the height of the centroid of the element A for which attribute information has not been determined is the same as or higher than the height of the centroid of the initial boundary element C, the attribute information for the element A for which attribute information has not been determined is , Determined as air. This comparison method is the same when comparing an element for which attribute information has been determined with an element for which attribute information has not been determined.

  Next, it is determined whether or not there is an element whose attribute information is adjacent to the element whose attribute information is determined to be the electrodeposition liquid and whose attribute information is not determined (step S55).

  If it is determined that there is no element for which attribute information has not been determined, (NO) analysis is terminated. On the other hand, if it is determined that there is an element for which attribute information has not been determined (YES), the attribute information adjacent to the element for which attribute information has been determined to be the electrodeposition liquid is not determined. The heights of the barycentric points are compared (step S56). If the height of the barycentric point of the element whose attribute information is not determined is lower than or equal to the height of the barycentric point of the element that is determined to be the electrodeposition liquid, the attribute information is determined as the electrodeposition liquid. In the case where the height of the center of gravity of the element for which the element is not determined is higher than the height of the center of gravity of the element for which the comparison target attribute information is determined to be the electrodeposition liquid, it is determined as air.

  Next, it is determined whether or not there is an element whose attribute information is not determined adjacent to the element whose attribute information is newly determined as the electrodeposition liquid (step S57). If it is determined that there is an element for which attribute information has not been determined (YES), the height of the center of gravity of each of the elements for which attribute information has been determined to be electrodeposition liquid and the elements for which attribute information has not been determined is compared. If it is determined that there is no element for which attribute information has not been determined (NO), the analysis of the member X is terminated.

  In addition, when there are a plurality of elements for which the initial boundary element and the attribute information have been determined from the viewpoint of the element for which the attribute information has not been determined, all the initial boundary elements or the elements for which the attribute information has been determined are compared with those initial boundaries. If it is determined that the attribute information that is the element or the electrodeposition liquid is lower than any one of the determined elements, the element for which the attribute information is not determined is determined to be the electrodeposition liquid.

  Then, a second determination step is performed for analyzing whether or not an air pool occurs with respect to the member Y to be analyzed. In the second determination step, first, a range of elements determined to be air in the member X is determined (step S6).

  Specifically, as shown in FIG. 10, first, after extracting the numbers given to the nodes of elements determined to be air, the X coordinate value, Y coordinate value, and Z coordinate value of those nodes are extracted.

  Next, it is determined whether or not there is a member not analyzed below the member X in the gravity direction (step S7). If it is determined that there is no unanalyzed member below the gravity direction of the member X (NO), the analysis is terminated (END). If it is determined that there is an unanalyzed member below the gravity direction of the member X (YES), it is determined whether or not an air pool occurs in the unanalyzed member Y below the gravity direction of the member X. (Step 8).

  Specifically, as shown in the flowchart of FIG. 11, first, consecutive numbers are assigned to elements adjacent to the end of the member Y and the hole Z, and the X coordinate value of each element, Y, as shown in FIG. 12. The coordinate value and the Z coordinate value are extracted and stored in the element table stored in the storage area of the control unit 5 (step S81).

  Next, the element with the smallest number among the elements with consecutive numbers is selected (step S82), and whether or not the X coordinate value of the node is included in the range of the X coordinate value of the range determined to be air. Is determined (step S83).

  If it is determined that the X coordinate value of the node is included in the range of the X coordinate value of the range determined to be air (YES), the Y coordinate value of the node is determined to be the Y coordinate of the range determined to be air. It is determined whether it is included in the range (step S84).

  If it is determined that the Y coordinate value of the node is included in the range of Y coordinate values of the range determined to be air (YES), the Z coordinate value of the range where the Z coordinate value of the node is determined to be air It is judged whether it is included in the range (step S85).

  If it is determined that the Z coordinate value of the node is included in the range of the Z coordinate of the range determined to be air (YES), the attribute information of the element including the node is determined to be air (step) S86).

  If it is determined in step S83 that the X coordinate value of the node is not included in the X coordinate value range of the air range (NO), the Y coordinate value of the node is included in the Y coordinate value range of the air range in step S84. If it is determined that there is no node (NO), and if it is determined in step S85 that the Z coordinate value of the node is not included in the range of the Z coordinate value of the air range (NO), the attribute of the element including the node is determined. Information is determined as an electrodeposition liquid (step S87).

  After the attribute information of the element including the node is determined to be air or electrodeposition liquid, the attribute information of all elements adjacent to the end of the member Y and the hole Z is either air or electrodeposition liquid. A determination is made as to whether or not the determination has been completed (step S88). If it is determined that the determination of the attribute information has not been completed for all elements adjacent to the end of the member Y and the hole Z (NO), the smallest number among the nodes with consecutive numbers is assigned. The selected node is selected (step S82), and it is determined whether or not the X coordinate value of the selected node is included in the range of the X coordinate value determined to be air (step S83).

  If it is determined that the attribute information is determined to be air or electrodeposition liquid for the element adjacent to the end of the member Y and the hole Z (YES), the analysis of the member Y ends. Then, it is determined whether there is another member below the member Y in the gravity direction (step S7).

  As described above, according to the invention according to the present embodiment, the stacked members are also analyzed in the order in which they are located in a high position in the direction of gravity, and the analysis results of the previously analyzed members are used for later analysis. By analyzing the members, it is possible to accurately perform the presence / absence of the air reservoir portion and the position of the air reservoir portion for all the laminated members, that is, the entire object to be coated.

  In addition, since it is possible to accurately analyze whether or not air accumulation occurs in an object to be coated in which a plurality of members are laminated, if an analysis result indicating that air accumulation occurs is obtained, the object to be painted is perforated. By changing the model to a model that has undergone a shape change and performing the analysis again, it is possible to predict the shape of the object to be coated in which no air accumulation occurs and promptly feed back to the object design. Thereby, the cost and schedule required for the development of the object to be coated can be shortened.

It is a schematic block diagram of a fluid analyzer. It is a flowchart of the air pocket generation | occurrence | production prediction method which concerns on this embodiment. It is the figure which divided | segmented the laminated member into the two-dimensional element. It is a flowchart for determining an analysis order. It is a table | surface showing the X-coordinate value, Y-coordinate value, and Z-coordinate value of each element of the member X and the member Y. It is a table | surface showing the largest coordinate value of a member name and the Z coordinate value of the element of each member. It is a table | surface showing the analysis name of a member name and each member. 5 is a flowchart showing a procedure for predicting the occurrence of air pockets about a member X. (A) is the figure which extracted a part of two-dimensional element of the member X, (b) is a top view of the element of (a). Table representing the node number of the element at the boundary between the element determined to be the electrodeposition liquid and the X coordinate value, Y coordinate value and Z coordinate value of the node among the elements determined to be air of the member X It is. 4 is a flowchart showing a procedure for predicting the occurrence of air pockets about a member Y. It is a table | surface showing the X-coordinate value of the edge part of the member Y which is an analysis object, and the node of the element of a hole part, a Y-coordinate value, and a Z-coordinate value. It is the figure which divided | segmented the member V and the member W which were laminated | stacked into the two-dimensional element. It is a cross-sectional schematic diagram showing the range where the air pocket of the member V and the member W generate | occur | produces. It is a cross-sectional schematic diagram showing the range judged that it is a range where the air pocket of the member X and the member Y generate | occur | produces by the conventional analysis method. FIG. 4 is a schematic cross-sectional view showing a range in which air is actually generated in member X and member Y.

Explanation of symbols

1 Fluid analyzer 2 CPU
3 ROM
4 RAM
5 Control unit

Claims (3)

An air pool occurrence prediction method for predicting an air pool in a dip coating of an object to be coated consisting of a plurality of laminated members by simulation,
An element dividing step of dividing the image data of the object on which the plurality of members are laminated into a plurality of elements for each member;
Among the plurality of members, the stacking order in the gravity direction is determined at the time of dip coating, analysis is performed in descending order, and for the members having a lower stacking order, an air pool occurrence portion is predicted based on the analysis result of the member having the higher stacking order. Analysis process to
A method for predicting the occurrence of air pockets. The analysis step includes, as an initial boundary element, an element adjacent to the end of the member and / or an element adjacent to the hole among the elements divided in the element dividing step;
A second step of determining the attribute information of the initial boundary element as liquid and setting the attribute information of other elements as gas;
A third step of comparing the heights of the elements in order from the element adjacent to the initial boundary element and determining the attribute information as liquid or air;
A fourth step of determining that there is an air reservoir when the element comparison is completed and there is an element whose attribute information is determined by air,
In the second step, when the position of the initial boundary element is an air reservoir portion of a member above the member, the attribute information is set as gas,
In the third step, the height of the element whose attribute information is determined to be liquid and the adjacent element are compared in height in the direction perpendicular to the immersion bath liquid level, and the attribute information of the adjacent element is determined to be liquid. If the attribute information of the adjacent element is higher than the determined element height, the attribute information of the adjacent element is determined to be air, and if the attribute information is the same as or lower than the height of the element determined to be liquid, the attribute information of the adjacent element is determined. The method for predicting the occurrence of air pockets according to claim 1, wherein the method is determined as liquid.   3. The method for predicting the occurrence of air pockets according to claim 2, wherein the third step compares the height of the barycentric coordinates of the respective elements.

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