JP2007114838A - Electrodeposition coating method, simulation program for electrodeposition coating, surface data generation method and surface data generation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a program, producing minimum data necessary for electrodeposition coating simulation from CAD data to perform the simulation. <P>SOLUTION: This electrodeposition coating method by which a body data 20 surface is applied electrodeposition-coating has: an obstacle model generation process for combining the body data 20 with a space lattice 21 formed at a prescribed pitch by use of the CAD data of the body data 20, and generating an obstacle model 22 of the body data 20 in boundary faces 21b of the space lattice 21; a simulation process for performing the simulation of the electrodeposition coating by use of the obstacle model 22 to determine a coating condition; and an electrodeposition coating process for performing the electrodeposition coating on the basis of the coating condition determined in the simulation process. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrodeposition coating performed on a production line of an automobile or the like, and more particularly to a simulation program for a spin coating with electrodeposition and a coating method using the result.

Electrodeposition coating is widely used as an undercoat for automobile bodies and parts. This coating is because the coating film is uniformly formed on the surface of the coated film and is excellent in corrosion resistance.
However, for structural members such as automobile front pillars, center pillars, and side frames that overlap steel plates for the purpose of reinforcement, the coating does not enter the overlapped portions of the steel plates, so the coating film is deposited. There is a problem that it is difficult.
For this reason, it is necessary to appropriately modify the shape of the portion where the coating film is difficult to deposit, such as adding a hole for guiding paint ions to the reinforcing member or increasing the interval between the members. However, since such a shape correction may greatly affect the structural strength of the body and members, it is necessary to repeatedly perform an electrodeposition coating analysis and a structural analysis study prior to actual vehicle evaluation by simulation. .

Patent Document 1 discloses a CAD data offset method that can automatically convert CAD data created as a surface model into FEM (structural analysis) data.
CAD data created as a surface model has position data of the surface constituting the outermost part, but in FEM used for structural analysis of a model of a plate body, for example, stress concentration analysis, The analysis is performed by setting the surface on the center plane of the body, that is, the half plate pressure portion.
Therefore, Patent Document 1 sets a lattice point on each surface constituting the shape data of the surface model, and obtains a moving lattice point by displacing the lattice point by ½ of the plate thickness in the normal direction of the surface. And a method of automatically generating FEM data of a continuous surface by complementing the edge portion of the surface.

On the other hand, Patent Document 2 is a document cited as the prior art of Patent Document 1 and discloses a CAD data offset method for automatically converting CAD data formed as surface data into FEM (finite element) mesh data. Yes.
In Patent Document 1, as a problem of Patent Document 2, when FEM data is generated from CAD data, if the quality of CAD data serving as the base of FEM data is poor, the labor required for restoration of CAD data increases. Cite.
In order to solve the problem, in Patent Document 1, a FEM mesh relating to a certain member is moved in the plate thickness direction of the member to generate a surface mesh in which the surface of the member is represented by a mesh. Then, the computer moves the surface mesh toward the outside of the member, thereby generating at least one space mesh expressing the space around the member by the mesh.
With the above configuration, various computer numerical analysis mesh data including electrodeposition coating, heat flow analysis, electric field analysis, and the like can be easily and efficiently generated from an FEM mesh in which the plate thickness of the member is not considered.
JP 2002-189761 A JP 7-282106 A

However, the technique of Patent Document 1 has the following problems.
(1) Since CAD data is automatically converted to generate FEM data, the amount of FEM data is enormous, and calculation takes time.
For example, when performing a simulation for electrodeposition coating in an electrodeposition coating performed on a production line of an automobile or the like, the part data of the body of the automobile in units of electrodeposition coating is converted into FEM data. There is a need. However, the current automobile body has a complicated three-dimensional shape that combines several steel plates to give rigidity by itself, and if detailed surface data is converted to FEM data, Time is required for the data conversion process.
The data required for the simulation, such as the simulation for surrounding coating with electrodeposition, is corrected if the specified performance does not appear as a result of the simulation. Since it may inevitably occur that trial and error are performed, if the calculation time of data necessary for one simulation can be shortened, the work efficiency will be improved.
When using the automatic conversion method used in Patent Document 2 such as Patent Document 1, accurate data can be obtained, but the data conversion process takes a lot of time and has been converted. Since the amount of data is enormous, it is a problem from the viewpoint of cost reduction because a computer is required to have high capacity and simulation time is required to perform simulation using the data. It was.

(2) When the FEM data is enormous, the entire analysis cannot be performed in 3D.
In particular, in an electrodeposition coating process performed on a production line of an automobile or the like, there are cases where data on the entire body of the automobile is required. In such a case, in order to perform a simulation using FEM data used in the finite element method obtained by converting detailed CAD data, the method of Patent Document 1 used in Patent Document 2 requires a large amount of data. Therefore, analysis with 2D data is limited, and analysis with 3D data cannot be performed.
Therefore, an analysis is performed on the picked-up cross section, and the overall state is assumed based on the result. However, since it is an evaluation for each cross section, it takes a lot of cross sections, and depending on how the cross section is taken, There were problems such as inability to perform correct data.

In other words, what can be said in common in (1) and (2) is that the amount of data used for simulation is enormous in the prior art, so that the simulation takes time and 3D analysis cannot be performed. .
SUMMARY OF THE INVENTION An object of the present invention is to provide a method and a program for performing simulation by creating minimum data necessary for simulation from CAD data.

In order to achieve the above object, the present invention has the following features.
(1) In the electrodeposition coating method in which the outer plate surface is electrodeposited, the outer plate is combined with a spatial grid formed at a predetermined pitch using CAD data of the outer plate, and the boundary of the spatial grid A calculation model generating step for generating a calculation model of the outer plate on the surface; a simulation step of performing coating deposition simulation using the calculation model to determine a coating condition; and the coating determined in the simulation step And an electrodeposition coating process for performing electrodeposition coating based on conditions.

The “spatial lattice” referred to here is a space that is divided into a lattice shape at an arbitrary interval. This interval is determined by the minimum information required for the simulation. For example, when the outer plate of an automobile body is coated by electrodeposition coating, the distance between the electrode-attached peripheral holes for guiding coating film ions and the like is determined. The lattice spacing in the vicinity thereof is determined by the size, the number, etc., and the lattice spacing may be wide in a portion where detailed data is not required. In this way, the lattice spacing can be changed and set depending on the location as necessary.
In addition, the “boundary surface of the spatial lattice” herein is a surface that is surrounded by adjacent lattice lines of the “spatial lattice”, and along the “boundary surface”, the “outer plate” “ A “calculation model” is generated. Unlike the difference mesh method used in the finite element method or the like, the “outer plate” data is defined as an obstacle along the “boundary surface” and is modeled as a surface.

The “calculation model” here refers to shape data necessary for the simulation. For example, when the surface data of the body of an automobile is created by 3D CAD data, as shown in Patent Document 1, the surface data is data indicating the outermost surface of the body. Inconvenient. This is because the automobile body is made of a steel plate and has a thickness. Therefore, it is necessary to change the CAD data to data used for simulation by processing the CAD data by some method. However, as mentioned in the problem here, if detailed data as it is is used for simulation, it takes time to calculate. By modeling CAD data, the calculation load can be reduced and the processing speed can be increased. It becomes possible.
In addition, the “coating conditions” referred to herein refers to data necessary for electrolytic coating such as potential data and coating characteristic data.

(2) The outer plate of the double structure including the outer plate and the inner plate is formed with a coating-coated peripheral hole for electrodeposition coating, and the outer plate surface is electrodeposited and then the coating is applied. In an electrodeposition coating method in which an inner plate surface is electrodeposited through a peripheral hole, the double structure is combined with a spatial grid formed at a predetermined pitch using CAD data of the double structure. A calculation model generating step of selecting the pitch so that the coating-coated peripheral holes appear on the calculation model diagram when generating the calculation model of the double structure on the boundary surface of the spatial lattice and the calculation A simulation process of performing electrodeposition coating using a model to determine the number or position of the peripheral holes with the coating film, and the double layer in which the peripheral holes with the coating film determined in the simulation process are formed Coating structure And having a electrodeposition coating step of performing electrodeposition coating as objects.

The term “dual structure” as used herein refers to a structure formed by stacking multiple steel plates such as the front pillar, center pillar, and side frame of an automobile, and requires electrodeposition coating to the inside. , “Having a hole with a coating” or the like having a hole for guiding a plurality of coating film ions.
In addition, “circumferential hole with coating film” as used herein refers to a hole that is formed so that coating film ions are also supplied to the inner plate surface or the outer side of the outer plate when performing electrodeposition coating. Yes, for example, in the case of an automobile body, a plurality of steel plates are combined to form a three-dimensional shape, but the inside of the frame of this body and the inside of the space in which the plates are overlapped are also rust-proof. Painting is necessary for a reason, and a plurality of holes are formed, and the entire coating is performed by electrodeposition coating.

(3) In the electrodeposition coating method described in (1) or (2), the simulation step stores an energization amount and basic film thickness data, and an energization amount and basic film resistance data. It is characterized by performing a simulation of electrodeposition coating using data.
(4) In an electrodeposition coating simulation program in which the surface of the outer plate is electrodeposited, the outer plate is combined with a spatial lattice formed at a predetermined pitch using CAD data of the outer plate, and the spatial lattice A calculation model generation step of generating a calculation model of the outer plate on the boundary surface of

(5) A coating structure for electrodeposition coating is formed on the outer plate of the double structure including the outer plate and the inner plate, and the outer plate surface is coated with the coating after the outer plate surface is electrodeposited. In a simulation program for electrodeposition coating in which the inner plate surface is electrodeposited through a perforation hole, a spatial lattice formed at a predetermined pitch using the CAD data of the dual structure. And a calculation model generation step of selecting the pitch so that the coating-coated peripheral holes appear on the calculation model diagram when generating the calculation model of the double structure on the boundary surface of the space lattice. It is characterized by having.

(6) In the electrodeposition coating simulation program described in (3) or (5), the energization amount and basic film thickness data, and the energization amount and basic coating resistance data are stored, and these data are used. It is characterized by conducting a simulation of electrodeposition coating.
(7) In the surface data generation method for generating the surface data of the plate, the plate is combined with a space lattice formed at a predetermined pitch using the CAD data of the plate, and the plate is formed on the boundary surface of the space lattice. And a calculation model generation step for generating a calculation model.
(8) Using the surface data generation program for generating the surface data of the plate and the CAD data of the plate, the plate is combined with a space lattice formed at a predetermined pitch, and the plate is formed on the boundary surface of the space lattice. It has the calculation model production | generation process which produces | generates a calculation model, It is characterized by the above-mentioned.

The present invention having such features can obtain the following operations and effects.
(1) In the electrodeposition coating method in which the outer plate surface is electrodeposited, the outer plate is combined with a spatial grid formed at a predetermined pitch using CAD data of the outer plate, and the boundary of the spatial grid A calculation model generating step for generating a calculation model of the outer plate on the surface; a simulation step of performing coating deposition simulation using the calculation model to determine a coating condition; and the coating determined in the simulation step It is characterized by having an electrodeposition coating process that performs electrodeposition coating based on conditions, so when performing electrodeposition coating simulation, the data amount of the calculation model used for the simulation can be reduced compared to the conventional, Simulation of electrodeposition coating is possible with 3D data, and calculation time and calculation model creation man-hours are shortened. As a result, production costs and delivery times can be reduced.

The data required for the simulation of electrodeposition coating only needs to be able to grasp the schematic shape of the part, and does not need to be as detailed as the CAD data.
On the other hand, the FEM data used in the finite element method can be simulated with a simpler shape than CAD data, so the amount of data can be reduced. It is not necessary as much as FEM data.
For example, if there is an octagonal work, the CAD data is a drawing for making a product. Therefore, a detailed drawing including the shape as well as the complicated shape of the surface is required. The FEM data necessary for the finite element method is data necessary for the simulation if the shape of the octagonal prism and rough irregularities can be reproduced. However, the data required for the simulation of electrodeposition coating does not differ greatly in the accuracy of simulation, regardless of whether the octagonal column is a hexagonal column shape or a cylindrical shape. This is because electrodeposition coating is a method in which a metal surface is coated through electricity, and the formation of a coating film is not greatly affected by the shape of irregularities or the like. That is, even if it is simplified to that extent, the simulation can be performed with a certain degree of accuracy.

Therefore, by generating a calculation model on the boundary surface of the spatial grid formed with the minimum pitch, it is possible to perform simulation with a data amount of 1/10 or less of conventional CAD data and FEM data. Therefore, the calculation speed can be increased. In addition, since the calculation model is generated on the boundary surface of the spatial grid formed with the minimum pitch, the amount of data to be handled is reduced, and the time required for modeling itself is shortened.
Furthermore, such simulations need to be repeated repeatedly, such as shape changes, etc., depending on the results, and the simulation accompanying the change must be repeated, so if one simulation time can be shortened The entire process is shortened, leading to shortened delivery times and reduced production costs.

(2) The outer plate of the double structure including the outer plate and the inner plate is formed with a coating-coated peripheral hole for electrodeposition coating, and the outer plate surface is electrodeposited and then the coating is applied. In an electrodeposition coating method in which an inner plate surface is electrodeposited through a peripheral hole, the double structure is combined with a spatial grid formed at a predetermined pitch using CAD data of the double structure. A calculation model generating step of selecting the pitch so that the coating-coated peripheral holes appear on the calculation model diagram when generating the calculation model of the double structure on the boundary surface of the spatial lattice and the calculation A simulation process of performing electrodeposition coating using a model to determine the number or position of the peripheral holes with the coating film, and the double layer in which the peripheral holes with the coating film determined in the simulation process are formed Coating structure It is characterized by having an electrodeposition coating process that performs electrodeposition coating as an object, so the calculation model required for simulation requires only the minimum amount of data, and it is possible to simulate electrodeposition coating with 3D data Thus, calculation time and calculation model creation man-hours can be reduced. As a result, production costs and delivery times can be reduced.

For structural members such as automobile front pillars, center pillars, side frames, etc., where steel plates are overlapped multiple times, the steel plates overlap and the paint does not easily enter. Shape correction such as addition to the members or widening the interval between the members is appropriately performed. Since the holes for guiding the coating film ions, that is, the peripheral holes with coating film, need to have a size of about φ15 to φ20, if the number, position, or interval of the holes are changed, the rigidity and appearance of the structural material It will be greatly related to design.
Therefore, by shortening the time for simulation of electrodeposition coating, if there is a structural change based on the result, the period to move to the study can be shortened, and then the simulation will be repeated repeatedly. It is possible to shorten the production period. Therefore, this leads to reduction in production cost and delivery time.

(3) In the electrodeposition coating method described in (1) or (2), the simulation step stores an energization amount and basic film thickness data, and an energization amount and basic film resistance data. Since the electrodeposition coating simulation is performed using the data, it is possible to have data necessary for the electrodeposition coating simulation and perform an accurate simulation. Therefore, the coating conditions can be easily determined by a highly reliable simulation.
(4) In an electrodeposition coating simulation program in which the surface of the outer plate is electrodeposited, the outer plate is combined with a spatial lattice formed at a predetermined pitch using CAD data of the outer plate, and the spatial lattice Since it has a calculation model generation step for generating a calculation model of the outer plate on the boundary surface, it is possible to reduce the data capacity compared to CAD data and to shorten the simulation time. There is an effect. As a result, production costs are reduced and delivery times are shortened.

(5) A coating structure for electrodeposition coating is formed on the outer plate of the double structure including the outer plate and the inner plate, and the outer plate surface is coated with the coating after the outer plate surface is electrodeposited. In a simulation program for electrodeposition coating in which the inner plate surface is electrodeposited through a perforation hole, a spatial lattice formed at a predetermined pitch using the CAD data of the dual structure. And a calculation model generation step of selecting the pitch so that the coating-coated peripheral holes appear on the calculation model diagram when generating the calculation model of the double structure on the boundary surface of the space lattice. Therefore, even in the calculation model of the double structure, there is an excellent effect that an accurate simulation is possible.

(6) In the electrodeposition coating simulation program described in (3) or (5), the energization amount and basic film thickness data, and the energization amount and basic coating resistance data are stored, and these data are used. Therefore, it is possible to perform an accurate simulation according to the actual electrodeposition coating.
(7) In the surface data generation method for generating the surface data of the plate, the plate is combined with a space lattice formed at a predetermined pitch using the CAD data of the plate, and the plate is formed on the boundary surface of the space lattice. Since the calculation model generation step for generating the calculation model is provided, it is possible to generate a model with the minimum necessary data in the simulation, and the calculation time can be shortened.
In this way, since the minimum necessary data can be provided for simulations other than electrodeposition coating, it is expected to contribute to shortening the calculation time in electroplating similar to the principle of electrodeposition coating and other simulations. .

(8) Using the surface data generation program for generating the surface data of the plate and the CAD data of the plate, the plate is combined with a space lattice formed at a predetermined pitch, and the plate is formed on the boundary surface of the space lattice. Since it has a calculation model generation process for generating a calculation model, it is possible to generate a model with a minimum amount of data in simulation, and an excellent effect is achieved that the calculation time can be shortened.

Examples of the present invention will be described below.
FIG. 1 shows a data conversion apparatus used in this embodiment.
The data conversion device 10 includes a computer 11 that performs calculation processing and graphic processing, an input device 12 such as a keyboard, a mouse, and a tablet, and an image output device 13 such as a monitor. The computer 11 includes a CPU 11a and a storage device 11b. Suppose you are.
The storage device 11b has workpiece CAD data and the like.
In the present embodiment, a simulation for performing electrodeposition coating on the body is performed using the computer 11 with the body data of the automobile as the work.

Next, FIG. 2 illustrates the general flow.
S1 is a basic data collection step, and basic experiment data is collected. Further, S2 is an obstacle model generation step, in which body data stored as CAD data is combined with a spatial grid to define an obstacle on the boundary surface and create an obstacle model. S3 is a calculation condition input step, in which the data obtained in S1 and the shape data in S2 are combined and output as a text file. S4 is an analysis step and calculates the film thickness.
After this, the process proceeds to the electrodeposition coating process based on the coating conditions indicating the result of good simulation, and actual coating is performed.

Hereinafter, the process will be described.
(Basic data collection process)
First, the basic data collection process will be described.
In the basic data collection process, basic data such as film thickness resistance and energization amount used for the analysis process, and the positional relationship with the electrode, potential, and the like are collected based on a simple basic experiment.
First, as a basic experiment, a steel plate for coating is prepared, and pseudo electrodeposition coating is performed to obtain coating condition data. The steel sheet for painting is a general steel sheet used for automobile bodies.
Incidentally, electrodeposition coating is a coating method that utilizes the electrophoresis phenomenon or electrodialysis phenomenon of a polymer electrolyte. That is, when a metal work is immersed in a paint tank filled with a water-based paint and a direct current is applied using the work as an anode or a cathode, the coating film forming component is charged negatively or positively and is electrodeposited on the work surface. In this way, a coating film is formed.
In the present embodiment, the case where cation electrodeposition is performed using a vehicle body as a workpiece will be described. Cationic electrodeposition is a method in which the workpiece is used as an anode, and the metal ions do not dissolve in the paint, so that the corrosion resistance is excellent. Therefore, the relationship between the film thickness, the coating film resistance, and the current can be grasped by passing a direct current through the paint tank filled with the paint, the electrode, and the steel sheet for painting.

In the basic experiment, instead of an automobile body, a sheet of steel sheet for painting is prepared as a work piece to be used as an anode and immersed in a paint tank. On the other hand, when a cathode is prepared in the paint tank and a direct current is passed through the anode and cathode,
(1) Water in the paint is electrolyzed. 2H ₂ O + 2e ⁻ → H ₂ + 2OH ⁻
(2) The coating film R is generated. OH ⁻ + RH ⁺ → R + H ₂ O
Such a chemical reaction occurs, and the coating film adheres to the steel plate as a workpiece and is painted.
In the painting process during the basic data collection process, the relationship between the current value, coating film resistance, and film thickness change with time as shown in FIG. 3 appears. FIG. 4 and FIG. 5 are scatter diagrams representing this in terms of the relationship between the energization amount and the coating film resistance, and the energization amount and the film thickness.
In FIG. 3, the horizontal axis represents elapsed time, and the vertical axis represents the increase in current value, film thickness, and coating film resistance. Although neither unit is shown, it can be seen that the current value curve 15, the film thickness curve 16, and the coating film resistance curve 17 are characteristically changed over time.
As shown in FIG. 3, the current value curve 15 increases rapidly until the coating film attached to the steel sheet reaches a certain amount of film thickness and the coating film resistance increases, but reaches the peak and adheres to the steel sheet. When the applied coating exceeds a certain amount of film thickness, it decreases thereafter.
The film thickness curve 16 has a large amount of current flowing through the steel sheet, and the amount of increase increases while the ion exchange is actively performed. When the coating film attached to the steel sheet reaches a certain amount of film thickness and it becomes difficult to perform ion exchange, the film thickness curve 16 gradually increases. increment the reduced, a shape close to a curve of y = t ^2.
The coating resistance curve 17 becomes a shape close to a curve of y ² = t, which increases slowly while the coating is thin, but increases with time.

In FIG. 4, the horizontal axis represents the amount of current (C / m ² ) and the vertical axis represents the film resistance (Ω · m ² ), and represents the relationship between the amount of current and the film resistance.
Of these, the legends are aV, bV, and cV, and data for three different potentials are acquired.
As shown in this scatter diagram, when all data are linearly approximated by the least squares method, they are represented by a single straight line. The amount of energization tends to increase as the coating resistance increases, and this relationship is almost independent of the potential. I understand. That is, the regression equation is represented by y = AX ₁ + BX ₂ −C. Incidentally, y is coating resistivity, _{X 1} is potential, _{X 2} is the amount of current, A, B, C are constants.

In FIG. 5, the relationship between the energization amount and the film thickness is shown with the energization amount (C / m ² ) on the horizontal axis and the film thickness (μm) on the vertical axis.
Among these, as in the case of the legend in FIG. 4, aV, bV, and cV are used, and data for three different potentials are acquired.
As shown in the scatter diagram, it can be seen that the energization amount and the film thickness have a directly proportional relationship at each potential, and a similar tendency is shown in the cases of aV, bV, and cV. That is, the regression equation is expressed as y = DX ₁ + EX ₂ −F. Incidentally, y thickness, _{X 1} is potential, _{X 2} is the amount of energization, D, E, F is a constant.
Such basic data is shown as a straight line as shown in FIGS. 4 and 5 by changing the characteristics depending on the characteristics of the paint, the thickness of the steel plate, the material, and the like. Therefore, such a basic data collection process needs to be taken again every time the model is changed.

(Obstacle model generation process)
Next, the obstacle model generation process will be described. In this step, a model is generated for use in the analysis.
Since this embodiment is a case where electrodeposition is applied to the body of an automobile, a model is created using the CAD data of the body. The CAD data is automatically defined as an obstacle on the boundary surface of the spatial grid by combining the plane elements of the CAD data and the spatial grid. Data defined as an obstacle on the boundary surface of the space grid is called an obstacle model.
Since the obstacle model defines body data as an obstacle on the boundary surface of the space grid, the defined body data has no thickness, and as an obstacle that obstructs the passage of paint and ions during electrodeposition coating. Configure the data.
Therefore, it is not possible to simulate the thickness direction of the plate, but since the thickness of the steel plate normally used for automobile bodies is about 1 mm, it does not make much sense in electrodeposition coating, so it greatly affects the simulation results. Don't give.

FIG. 6 shows how the body data 20 is actually combined with the spatial grid to generate the obstacle model 22.
The body data 20 is a planar element of CAD data showing a part of the locker portion of the automobile, and the space grid 21 is an area obtained by dividing the space by grid lines 21a.
Then, by combining the body data 20 and the spatial grid 21, an obstacle model 22 is completed. The obstacle model 22 is body data 20 defined as an obstacle on the boundary surface 21 b of the space lattice 21, and the boundary surface 21 b is a surface surrounded on all sides by the lattice lines 21 a of the space lattice 21. In this case, the XY plane, the XZ plane, and the YZ plane surrounded by the lattice lines 21a drawn in the X, Y, and Z directions become the boundary plane 21b.
That is, it can be said that the rough shape data merely representing the presence or absence of the obstacle in the body data 20 is the obstacle model 22.

By defining the body data 20 as an obstacle on the boundary surface 21b of the spatial grid 21 defined as described above and using the obstacle model 22, the data amount can be reduced more than the data of the body data 20 itself. I can do it.
This is because if the data of the body data 20 is CAD data, it has a dimensional accuracy of about 0.1 mm because it is produced by press molding, while the reason will be described later, the obstacle model 22 itself is 5-10 mm. This is because only a spatial grid with a certain interval is required, and since an oblique surface or the like is not stored as data, the data only needs to represent rough plane elements.
This is because, if considered simply, the dimensional accuracy is from 0.1 mm unit to 10 mm unit, so if the two-dimensional concept is used, the obstacle model 22 has an amount of 1/100 of the CAD data. Data will be sufficient and the amount of data will obviously be reduced. Therefore, if it becomes 3D data, the data amount will be further compressed more than 1/100.
Of course, in reality, the CAD data and the obstacle model 22 have different data representation methods and different data compression means, so the amount of data is not simply reduced to 1/100 or less. Since the shape of the complicated press curve by the 3D curve is simplified to the data combining the plane elements, the data amount can be surely reduced and a great effect can be obtained.

Next, a mesh setting method for the lattice lines 21a of the space lattice 21 will be described.
Naturally, the narrower the interval between the lattice lines 21a of the spatial lattice 21, that is, the more the mesh is cut, the more faithfully the body data 20 can be expressed. However, the amount of data increases proportionally, and the time required for calculation increases. Therefore, it is desirable that the obstacle model 22 be defined with the minimum required mesh roughness.
In this embodiment, it is necessary to obtain an obstacle model 22 for performing a simulation of electrodeposition coating, but it is first necessary to explain what data is necessary for electrodeposition coating.

As described above, in electrodeposition coating, when a metal work is immersed in a paint tank filled with a water-based paint and a direct current is applied to the work as an anode or cathode, the coating film forming component is negatively charged, Electrodeposit on the workpiece surface. Since this is a method for forming a coating film, the coating film ion RH ⁺ present in the coating material adheres to the anode body surface attracting the hydroxide ion OH ^−, and becomes coating film R and water H ₂ O. The coating film R needs to be electrodeposited on the body surface.
That is, it is necessary that the body surface is charged to the anode, and coating film ions RH ⁺ generated on the electrode side are supplied to the body surface charged to the anode.
FIG. 7 to FIG. 10 are diagrams illustrating the electrodeposition-around mechanism.
FIGS. 7 to 10 show a simplified cross section of the rocker portion of the body. In this figure, a mechanism with electrodeposition in the cross section is described for the sake of explanation.
The inner plate 30 and the outer plate 31 constituting the dual structure model 41 are connected to a DC power source 33 and serve as anodes. On the other hand, the electrode 32 is connected to a direct current power source 33 to form a cathode.
Each of the inner plate 30 and the outer plate 31 is in a state of being immersed in a paint tank filled with a water-based paint.

Around the electrode 32, water is electrolyzed to become 2H ₂ O + 2e ⁻ → H ₂ + 2OH ⁻ , and hydroxide ions OH ⁻ are generated. This state is shown in FIG. 7, and the hydroxide ions OH ⁻ are attracted to the surfaces of the inner plate 30 and the outer plate 31 which are the double structure model 41 as the anode.
Then, the coating film ion RH ⁺ in the coating material reacts with the hydroxide ion OH ⁻ to generate the coating film R on the surfaces of the inner plate 30 and the outer plate 31 that are the dual structure model 41. The state is shown in FIG. 8, and first, it can be seen that the coating film R starts to be generated from the outer surface of the outer plate 31.
Since the coating film R starts to be generated from the side close to the electrode 32 where current easily flows, the coating film R starts to be generated from the outer surface of the outer plate 31, but when the coating film R is generated on the surface of the outer plate 31. The electrical resistance of the surface becomes high, and the coating film ions RH ⁺ are difficult to adhere. This is as shown in FIG. 4, and when a certain amount or more of the coating film R is generated, the amount of flowing current decreases.

Then, hydroxide ions OH ⁻ are easily attracted to the surface where the coating film R is not generated, and the coating film ion RH ⁺ reacts on the surface where the coating film R is not generated and starts to generate the coating film R.
When the generation of the coating film R on the outer surface of the outer plate 31 is finished, the resistance value of the outer surface of the outer plate 31 increases uniformly. At this time, if coating with around holes 31a are spaced, hydroxide Coated around hole 31a ions OH ^- coating is passed through the inner surface and the outer surface of the inner plate 30 of the outer plate 31 R is easily generated. The state is shown in FIG. 9, and it can be seen that the coating film ion RH ⁺ that has passed through the coating-coated peripheral hole 31a is generated from the front side. In addition, in FIG. 10, since the coating film R produced | generated in the near side, the resistance value of the surface becomes high and the mode that the coating film R is produced | generated in the back is shown.

In this way, the coating film R is generated, and it is understood that the coating-coated peripheral holes 31a are necessary to uniformly generate the coating film R up to the inside of the inner plate 30 and the outer plate 31.
Due to the principle of electrodeposition coating described above, the presence of the coating-coated peripheral hole 31a is important in the simulation, and the obstacle model 22 has a hole such as the coating-coated peripheral hole 31a. It needs to be represented.
The size of the coating-coated peripheral hole 31a required in the electrodeposition coating is usually about 15 to 20 mm, so that the coating film ions RH ⁺ and hydroxide ions OH ⁻ can be sufficiently introduced. The plate 31 needs to be provided with a plurality of coating-coated peripheral holes 31a.
However, the body of an automobile is made of a steel plate, and its rigidity is also maintained by three-dimensionally bonding the steel plates. Therefore, opening the coating-coated peripheral holes 31a in the outer plate 31 and the inner plate 30 for maintaining the rigidity greatly affects the design, rigidity, and the like.

Next, in the obstacle modeling, whether or not the coating-coated peripheral hole 31a is represented in the obstacle model 22 is determined by how to cut the mesh of the spatial grid 21, but how the actual 3D data is represented. FIG. 11 to FIG. 13 show how the obstacle model 22 is converted. FIG. 14 and FIG. 13 show how the coating hole 31a with the coating film can be expressed in the obstacle model 22 when the mesh of the spatial grid 21 is set. 15 will be described.
First, an example of conversion of 3D data is shown.
11 to 13 are one part of the body data of the rocker part, and are three-dimensional CAD data of the rocker part inner plate 50. FIG. 12 and FIG. 13 are obstacle models based on the data of the locker section inner plate 50. In practice, in the state shown in FIG. 16, a plurality of steel plates are combined to form a rocker portion, and electrodeposition coating is performed in the combined state. Extract parts and explain.
The simple body data 50A of the locker unit inner plate 50 in FIG. 12 and the simple body data 50B of the locker unit inner plate 50 in FIG. 13 are obtained by changing the conditions for automatic modeling.
By automatically modeling the rocker unit inner plate 50, the drain hole 50a provided in the locker unit inner plate 50 disappears in the simple body data 50A. The drain hole 50a has the same function as the coating-coated peripheral hole 31a shown in FIGS. Therefore, even if the simple body data 50A in which the drain hole 50a has disappeared on the data is used for the simulation of electrodeposition coating, an appropriate result cannot be obtained. This is because the place where the coating film ion RH ⁺ and the hydroxide ion OH ⁻ are introduced, that is, the drain hole 50a is lost.

The electrodeposition coating is performed in a state where the locker portion inner plate 50 itself is a part of the body of the locker portion of the automobile and is combined with other parts. Therefore, the simple body data 50 </ b> A is not a simple body data 50 </ b> A alone, but needs to be simulated in combination with other obstacle modeled models, and is a long part for the rocker unit inner plate 50. In this case, there is a high possibility that the coating film ions RH ⁺ and hydroxide ions OH ⁻ do not turn around the center. Therefore, when the simple body data 50A is simulated in combination with another model, it can be expected that a calculation result that a portion with a thin coating is formed inside will be obtained.
On the other hand, the drainage hole 50a of the rocker part inner plate 50 is reproduced in the simple body data 50B of FIG.
If the simple body data 50B in which the drain hole 50a is appropriately reproduced in this way is combined with another model to simulate electrodeposition coating, an appropriate result can be obtained for the effect of the drain hole 50a. Can be expected.

Next, a mesh setting method for the space lattice 21 will be described.
The difference between the simple body data 50A and the simple body data 50B is caused by the difference in mesh setting location.
FIG. 14 shows a case where the mesh is partially cut fine in (a) and automatically converted into simple body data in (b).
FIG. 15 shows a case where the mesh is cut based on the drain hole in (a) and automatically converted into simple body data in (b).
14 (a) and 15 (a) are cross-sectional CAD data of the rocker portion of the body of the automobile, and are the same figure, but the interval, the number, and the position of the grid lines that cut the mesh are different.

Actually, the obstacle model is created using the three-dimensional CAD data, but here, for the sake of explanation, the explanation will be made with a 2D sectional view.
In short, the method for constructing the obstacle model is to construct the data by defining the cross-sectional line of the CAD data as an obstacle on the nearest lattice line.
For example, if there is a lattice line and a lattice plane that is an area surrounded by the lattice line, if no cross-section line of CAD data crosses the lattice plane, it is not defined as an obstacle.
When the cross section line of the CAD data crosses the lattice plane, when the cross section line is close to the lattice line, the closest lattice line is defined as an obstacle. When the cross-sectional line crosses the lattice plane diagonally and is close to two lattice lines, the two lattice lines are defined as obstacles.
Even if the cross section line crosses the lattice plane, it is not defined as an obstacle if only a part of it crosses. Conversely, if the cross-sectional line crosses about half of the lattice plane, it is defined as crossing the entire lattice line closest to it.
However, these relationships are determined by looking at the relationship between the eight adjacent lattice planes. If the cross-sectional line of CAD data is continuous data, the data defined as an obstacle on the lattice line is also defined as continuous. An obstacle model needs to be formed.

In the generation of such an obstacle model, if there are a plurality of lines on the lattice plane, there is a possibility that the processing is not appropriately performed.
If all surfaces need to be electrodeposited, it is necessary that the obstacles defined as the obstacle model have a certain distance between them. For example, there are almost three cross-sectional lines on the lattice plane. In the case of crossing in parallel, there are two obstacles defined on the nearest grid line. When simulation is performed, the result is that no coating film is formed on the obstacle that was not expressed. Because it becomes.
In addition, a hole for coating film ions to pass through must also be represented on the obstacle model.
If there is no drain hole, ions such as coating film ions RH ⁺ and hydroxide ions OH ⁻ are not guided, so that electrodeposition coating is not performed well.
Accordingly, the spacing between the grid lines is determined by the required width between the steel holes necessary for drain holes and electrodeposition coating, and the drain holes need to be about φ15 to φ20 as described above. 5-10 mm is sufficient.

  In electrodeposition coating simulations, the spacing of the space grid mesh is determined by the size of the peripheral holes with electrodeposition coating, such as drain holes, but when this method is used for other simulations, etc. The spatial grid mesh is determined by factors such as the size of the drain holes in the electrodeposition coating, so that the electrodeposition coating method, the electrodeposition coating simulation program of the present invention, the surface data generation method, and A surface data generation program can be applied.

This will be specifically described with reference to FIGS. 14 and 15 as follows.
In FIG. 14, the mesh in the vicinity of the drain hole is partially cut finely, but in FIG. 14 (b), the drain hole is not reproduced and is crushed. This is because there is only one body line between the parts where the grid lines indicate drain holes, and the body lines are defined as obstacles on the grid lines when automatically modeling. It is.
In the case of this method, unless there are two or more grid lines between the parts where the body line indicating the drain hole is interrupted, it is not recognized as a hole in automatic modeling.
In the state of the obstacle model shown in FIG. 14B in which the mesh is cut and automatically modeled as described above, an appropriate result cannot be obtained even if simulation is performed in the same manner as the simple body data 50A. This is because the holes through which the coating film ions pass during the electrodeposition coating are not expressed, and the coating film ions do not pass through the portion in the simulation. Accordingly, it is necessary to further cut the mesh.
However, such a process is not preferable because the data amount increases by finely cutting the mesh and affects the calculation speed.

On the other hand, in FIG. 15A, the mesh itself is rougher than in FIG. 14A, but there is one grid line in the part where the body line representing the drain hole is broken in FIG. However, in contrast to the case where there are only two grid lines in FIG.
As a result, in FIG. 15B in which FIG. 15A is automatically modeled, the water drain hole is reproduced exactly. In this state, similar to the simple body data 50B, a simulation is performed to obtain an appropriate result.
Further, since the mesh in FIG. 15 (a) is rougher than that in FIG. 14 (a), FIG. 15 (b) is compared with FIG. The amount of data in the data b) is reduced by the amount of the rough mesh.
This is because the grid lines are defined by focusing on the drain holes. As shown in FIG. 15A, the positions of the grid lines are set around the four grid lines indicated by the alternate long and short dash lines, and the mesh is set. By cutting, it becomes possible to express the drain hole without making the mesh fine.
By setting grid lines and cutting the mesh in this way, the mesh does not need to be made finer than necessary, and if an obstacle model is created with a mesh of drain holes, that is, a mesh with a spacing of 15-20 mm, the simulation is Will be done appropriately.
In addition, if the mesh of FIG. 15 (a) has an appropriate mesh interval, the mesh position is shifted from the state where the mesh is cut as shown in FIG. 14 (a) so that the drain hole appears. You may perform operation which makes 2 or more grid lines enter the part which the body line showing the water drain hole interrupted.
If 3D CAD data is also processed in accordance with the method shown in FIG. 15 as described above, it is possible to define necessary data and create an obstacle model, such as the simplified body data 50B shown in FIG. Data will be obtained.

(Calculation condition input process)
In the calculation condition input process, the electrode position, potential data, paint characteristic data, etc. obtained as basic data, and the obstacle model obtained in the obstacle model generation process are edited as text data in a text file. To do.
A simulation is performed using this text file.
(Analysis process)
In the analysis process, simulation is performed based on the calculation data thus obtained to calculate the film thickness.
If the film thickness is obtained by simulation and it can be confirmed that the coating film can be uniformly formed to the required film thickness, the coating conditions are determined, so the process proceeds to the electrodeposition coating process and the electrodeposition coating is actually performed.
In addition, if the simulation result that the film thickness of the coating film R to be generated varies and a sufficient film thickness cannot be obtained is obtained, the design changes such as changing the position of the body data and the peripheral hole with the coating film, etc. To change the coating conditions, repeat the simulation again, and make adjustments to obtain good results.

As described above, the design data that can generate a good film thickness of the coating film R is obtained by the electrodeposition coating method of the present invention and the electrodeposition coating simulation program, and the design is performed after the production is actually performed. Since there is no need to start over, and the data of the calculation model used for the simulation is small, the simulation can be performed in a short time, which contributes to the reduction of the design cost.
The results are shown in FIGS. 16 to 24. The simulation accuracy of the simulation using the obstacle model was obtained by performing a simulation and actually measuring the film thickness. The data is compared.
FIG. 16 is a schematic cross-sectional view of the vicinity of the rocker portion. The multiple structure 40 includes a rocker portion outer plate 51, a rocker portion inner plate 50, and a rocker portion inner plate 52, and the relative positions of the components of the multiple structure 40. Showing the relationship.
The locker part of an automobile is composed of a combination of multiple steel plates to increase body rigidity, and it is necessary to carry out anticorrosion coating with a thickness of several tens of μm by electrodeposition coating to the inside. It is important to do.
Accordingly, the rocker unit inner plate 50 is changed to the simple body data 50B, and although not shown, the locker unit outer plate 51 is changed to the simple body data 51B, the locker unit inner plate 52 is changed to the simple body data 52B, and the simple body data 50B. The simulation is performed by combining with the spatial grid 21 as shown in FIG.

FIG. 17 is a view of the rocker part outer plate 51 as seen from the inside of the vehicle, and numbers 1 to 8 are described at the positions where data is measured.
FIG. 18 is a comparison graph of the calculated value obtained by the simulation corresponding to FIG. 17 and the actually measured value obtained by actually performing the electrodeposition coating to measure the film thickness. The horizontal axis represents data of the C1 to C8 parts corresponding to the numbers 1 to 8 in FIG. 17, and the vertical axis represents the film thickness (μm).
According to this data, except for C3, the calculated value is slightly thicker than the actually measured value, and in other parts, the calculated value tends to be slightly thinner than the actually measured value. However, there is no large gap between the calculated value and the measured value in any part, and the difference is only about several percent of the whole. Moreover, the substantially uniform film thickness of the coating film R is obtained in each part.
In particular, C1 to C8 hit the inside of the rocker part outer plate 51 and are places where the coating film ions RH ⁺ and hydroxide ions OH ⁻ are difficult to go around. 7 to FIG. 10, the coating film ion RH ⁺ and the hydroxide ion OH ⁻ are properly guided, and the coating film R can be applied anywhere in C1 to C8. It can be seen that is uniformly formed.

FIG. 19 is a view of the rocker portion inner plate 50 as viewed from the outside of the vehicle, and numbers 9 to 12 are described at the positions where data is measured.
FIG. 20 is a comparison graph between the calculated value obtained by the simulation corresponding to FIG. 19 and the actual value obtained by actually performing the electrodeposition coating to measure the film thickness. The abscissa indicates the data of C9 to C12 corresponding to the numbers 9 to 12 in FIG. 19, and the ordinate indicates the film thickness (μm).
According to this data, the calculated values tend to be slightly thicker than the measured values at any location, but there is no significant difference between the calculated values and the measured values at any location, The difference is only around several percent, and a substantially uniform film thickness of the coating film R is obtained at each site.
Since the rocker part inner plate 50 hits the inner side of the rocker part outer plate 51, the coating film ions RH ⁺ and hydroxide ions OH ⁻ are difficult to be guided, but the rocker part outer plate 51 is provided with the rocker outer plate drain holes 51a properly. Therefore, it can be seen that the coating film R is uniformly formed in any place of C9 to C12.

FIG. 21 is a view of the rocker portion inner plate 50 as seen from the inside of the vehicle, and numbers 13 to 17 are written at the positions where data is measured. 11 and FIG. 19 and the rocker part inner plate 50 of the diagram space lattice 21 are different in shape, because this is data extracted from the portions necessary for evaluation.
FIG. 22 is a comparison graph of the calculated value obtained by the simulation corresponding to FIG. 21 and the actually measured value obtained by actually performing the electrodeposition coating to measure the film thickness. The horizontal axis shows the data of the parts C13 to C17 corresponding to the numbers 13 to 17 in FIG. 21, and the vertical axis shows the film thickness (μm).
According to this data, it can be seen that the calculated values tend to be slightly thicker than the actually measured values at locations other than C14, and the film thicknesses are thin at C14 and C15. However, there is no large gap between the calculated value and the measured value in any part, and the difference is only about several percent of the whole.
Since the rocker part inner plate 50 hits the inner side of the rocker part outer plate 51 and hits the inner side of the multiple structure 40, the inner side is evaluated in FIG. 22, so that the coating ions RH ⁺ and hydroxide ions OH ⁻ are present. It is difficult to guide, and the film thickness is thinner at C14 and C15 than at other parts.
Since this is also related to the rocker part outer plate 51, when changing the design, it is necessary to devise the shape of each and the shape of the drain hole, so the simulation is performed again after changing the design. It will be.

FIG. 23 is a view of the rocker portion inner plate 52 as viewed from the outside of the vehicle, and numbers 18 to 21 are written at the positions where data is measured.
FIG. 24 is a comparison graph of the calculated value obtained by the simulation corresponding to FIG. 23 and the actually measured value obtained by actually performing the electrodeposition coating to measure the film thickness. The abscissa indicates the data of C18 to C21 corresponding to the numbers 18 to 21 in FIG. 23, and the ordinate indicates the film thickness (μm).
According to this data, it can be seen that the calculated values tend to be slightly thicker than the actually measured values at locations other than C19, and the film thickness is thin at C19 and C20. However, there is no large gap between the calculated value and the measured value in any part, and the difference is only about several percent of the whole.
Locker unit inner plate 52 strikes the inner side of the rocker portion plate 50, and, to hit the inside of the multi-structure 40, coating ion RH ⁺ and hydroxide ion OH ^- hardly is led, the other is the thickness in the C19 and C20 It is thinner than the part of.
Since this is also related to the rocker part inner plate 50 and the rocker part outer plate 51, when making a design change, it is necessary to devise the shape of each and the shape of the drainage hole. The simulation will be performed again.

In this way, the calculated value obtained by the simulation with the calculation model using the obstacle model in the method of the present embodiment and the actual value obtained by actually performing the electrodeposition coating to measure the film thickness are in any place. As for the portion where the result that the film thickness of the coating film R becomes thin is obtained by simulation, the film thickness of the coating film R is thin even in the actual measurement value.
Of course, the actual measurement value and the calculated value do not completely coincide with each other, and the results are slightly different in any case. However, the rust-proof coating film using electrodeposition coating applied to automobile bodies is generally several tens of μm, and all measured values sufficiently satisfy the standard and are simulation results. The calculated value has an error of only a few percent compared to the measured value. That is, it can be said that the calculation accuracy by simulation is sufficiently maintained.
Therefore, it has been confirmed that a highly reliable film thickness is required by simulation with a calculation model using an obstacle model.

  From this result, even when creating data for simulation by modeling obstacles using such a spatial grid other than electrodeposition coating, if even the spacing of the reference spatial grid mesh is set appropriately, It can be seen that it is possible to perform an appropriate simulation after compressing the data amount further than the FEM data used in the conventional finite element method.

According to the electrodeposition coating method and the electrodeposition coating simulation program of the present invention described above, the following excellent actions and effects can be obtained.
(1) In the electrodeposition coating method in which the surface of the body data 20 is electrodeposited, the body data 20 is combined with the space grid 21 formed at a predetermined pitch by using the CAD data of the body data 20, and the space grid 21 An obstacle model generation step of generating an obstacle model 22 of the body data 20 on the boundary surface 21b of the vehicle, a simulation step of simulating electrodeposition coating using the obstacle model 22 and determining a coating condition, and a simulation step And the electrodeposition coating process for performing electrodeposition coating based on the coating conditions determined in the above. Therefore, when the simulation of electrodeposition coating is performed, the data amount of the obstacle model 22 used for the simulation is conventionally Compared to, 3D data makes it possible to simulate electrodeposition coating, and the calculation time Obstacle model 22 creating man-hours is reduced. As a result, production costs and delivery times can be reduced.

  The data necessary for the simulation of the electrodeposition coating only needs to be able to grasp the general shape of the body data 20, and does not need to be as detailed as the CAD data. The FEM data used in the finite element method can be simulated with a simpler shape than CAD data, so the amount of data can be reduced. However, the accuracy of electrodeposition coating simulation is limited to conventional FEM data. Not as much as data. That is, it is possible to obtain a calculation result with sufficient accuracy for electrodeposition coating even by simulation using data simplified to some extent.

Therefore, by generating the obstacle model 22 on the boundary surface 21b of the spatial grid 21 formed with the minimum necessary pitch from the body data 20, the amount of data is less than 1/10 of conventional CAD data and FEM data. Since simulation can be performed, calculation speed can be increased. Further, since the obstacle model 22 is generated on the boundary surface 21b of the spatial lattice 21 formed with the minimum pitch, the amount of data to be handled is reduced, and the time required for modeling itself is shortened.
Furthermore, such simulations need to be repeated repeatedly as the result of specification changes such as shape changes depending on the results, and the simulation accompanying the change must be repeated, so if one simulation time can be shortened The entire process is shortened, leading to shortened delivery times and reduced production costs.

(2) A rocker outer plate drain hole 51a for electrodeposition coating is formed in the rocker unit outer plate 51 of the multiple structure 40 including the rocker unit outer plate 51, the rocker unit inner plate 50, and the rocker unit inner plate 52. In the electrodeposition coating method, after the surface of the rocker portion outer plate 51 is electrodeposited on the locker portion inner plate 50, the surface of the rocker portion inner plate 50 is electrodeposited through the rocker outer plate drain hole 51a. 40, the spatial lattice 21 in which the multiplex structure 40 is formed at a predetermined pitch as shown in FIG. 6 using CAD data of the rocker part inner plate 50, the rocker part outer plate 51, the rocker part inner plate 52, and the like. When the simple body data 50B, simple body data 51B, and simple body data 52B of the multiple structure 40 are generated on the boundary surface 21b of the space lattice 21, the drain holes 50a are formed. The obstacle model generation process for selecting the pitch, the simple body data 50B, the simple body data 51B, and the simple body data so that the rocker outer plate drain holes 51a appear on the simple body data 51B diagram on the easy body data 50B diagram. 52B is used to simulate electrodeposition coating to determine the number or position of the drain holes 50a, rocker outer plate drain holes 51a, etc., and the drain holes 50a determined by the simulation process, outside the rocker And having an electrodeposition coating process in which electrodeposition coating is performed using the multiple structure 40 in which the plate drain holes 51a and the like are formed as an object to be coated. In the data 51B and the simple body data 52B, only the minimum required data amount is required. Simulation of in the electrodeposition coating becomes possible, it is possible to reduce the computation time and computational model created man-hours. As a result, production costs and delivery times can be reduced.

For example automobile front pillar and a center pillar, the side frames or the like, for over and over again overlapping causes structural members steel plates, to the steel sheet is hardly enters overlap paint, the coating film is hardly precipitated, coating ion RH ⁺ and water Shape correction such as adding a hole for guiding the oxide ion OH ⁻ to the reinforcing member or increasing the interval between the members is appropriately performed. The holes for guiding the coating film ions RH ⁺ and the hydroxide ions OH ^−, that is, the coating-coated peripheral holes 31a in FIGS. 7 to 10 need to have a size of about φ15 to φ20. If the position, the interval, or the distance is changed, it greatly affects the rigidity of the structural material.
Therefore, by shortening the time for simulation of electrodeposition coating, if there is a structural change based on the result, the period to move to the study can be shortened, and then the simulation will be repeated repeatedly. It is possible to shorten the production period. Therefore, this leads to reduction in production cost and delivery time.

(3) In the electrodeposition coating method described in (1) or (2), the simulation process stores the energization amount and basic film thickness data, and the energization amount and basic film resistance data, and these data Therefore, it is possible to carry out an accurate simulation with data necessary for the simulation of electrodeposition coating. Therefore, the coating conditions can be easily determined by a highly reliable simulation.
(4) In the electrodeposition coating simulation program in which the surface of the outer plate 31 is electrodeposited, the outer plate 31 is combined with the space lattice 21 formed at a predetermined pitch using the CAD data of the outer plate 31, and the space Since it has an obstacle model generation step for generating a calculation model of the outer plate 31 on the boundary surface 21b of the lattice 21, it is possible to reduce the data capacity compared to CAD data and to shorten the simulation time. It has an excellent effect of becoming. As a result, production costs are reduced and delivery times are shortened.

(5) The rocker outer plate 51 for the electrodeposition coating is drained on the rocker unit outer plate 51 and the rocker unit inner plate 50 of the multiple structure 40 including the rocker unit outer plate 51, the rocker unit inner plate 50, and the rocker unit inner plate 52. After the hole 51a and the drain hole 50a are formed and the surface of the rocker part outer plate 51 is electrodeposited, the surface of the rocker part inner plate 50 is electrodeposited via the rocker outer plate drain hole 51a, and the drain hole 50a. In the electrodeposition coating simulation program in which the inner surface of the rocker portion inner plate 50 and the inner surface of the rocker portion inner plate 52 are electrodeposited via the CAD data of the multiple structure 40, the multiple structure 40 is formed at a predetermined pitch. When the obstacle model of the multiple structure 40 is generated on the boundary surface 21b of the space lattice 21 in combination with the formed space lattice 21, the drain hole 50a and the outside of the rocker Since there is an obstacle model generation step for selecting a pitch so that the drain holes 51a and the like appear on the obstacle model diagram, accurate simulation is possible even in the obstacle model of the multi-structure 40. It has an excellent effect of becoming.

(6) In the electrodeposition coating simulation program described in (3) or (5), the energization amount and basic film thickness data, and the energization amount and basic coating resistance data are stored, and these data are used. Therefore, it is possible to perform an accurate simulation according to the actual electrodeposition coating.
(7) In the surface data generation method for generating the surface data of the plate, the plate is combined with the spatial lattice 21 formed at a predetermined pitch using the CAD data of the plate, and the boundary surface 21b of the spatial lattice 21 is Since the obstacle model generation step for generating the obstacle model 22 is provided, a model can be generated with a minimum amount of data in the simulation, and the calculation time can be shortened.
In this way, since the minimum necessary data can be provided for simulations other than electrodeposition coating, it is expected to contribute to shortening the calculation time in electroplating similar to the principle of electrodeposition coating and other simulations. .

(8) Using the surface data generation program for generating the surface data of the plate and the CAD data of the plate, the plate is combined with the space lattice 21 formed at a predetermined pitch, and the boundary surface 21b of the space lattice 21 is obstructed by the plate. Since it has an obstacle model generation step for generating the object model 22, it is possible to generate a model with the minimum necessary data in the simulation, and an excellent effect is obtained that the calculation time can be shortened.

In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning.
For example, in this embodiment, a simulation for electrodeposition coating of an automobile body was performed, but it is not particularly limited to electrodeposition coating. For example, electroplating can be performed by appropriately changing the mesh roughness or mesh setting position. It can also be used for analysis of finite element methods.

1 shows a data conversion apparatus according to the present embodiment. A rough flow of simulation in this embodiment is shown. The current value, the coating film resistance, and the film thickness change of the basic data in this example are shown. The relationship between the energization amount and the coating film resistance in this example is shown. The relationship between the energization amount and the film thickness in this example is shown. In this embodiment, the CAD data plane element and the spatial grid are combined. It is FIG. 1 explaining the surrounding mechanism with electrodeposition in a present Example. It is FIG. 2 explaining the surrounding mechanism with electrodeposition in a present Example. FIG. 3 is a third view for explaining a mechanism with electrodeposition in the present embodiment. FIG. 4 is a fourth diagram for explaining an electrodeposition-around mechanism in the present embodiment. The CAD figure of the rocker part inner board in a present Example is shown. The simple body data which could not reproduce the drain hole of the rocker part inner board in a present Example are shown. The simple body data which reproduces the drain hole of the rocker part inner board in a present Example is shown. It is a mode that the mesh was cut into CAD data sectional drawing of the locker part of a car in this example. It is a mode that the mesh was cut | disconnected according to the drain hole of CAD data sectional drawing of the rocker part of a motor vehicle in a present Example. It is a schematic cross section of a multiple structure in a present Example. It is CAD data seen from the vehicle inner side of the rocker part outer plate | board in a present Example. It is evaluation data of the rocker part outer plate | board in a present Example. It is CAD data of the vehicle outer side of the rocker part inner plate in a present Example. It is the evaluation data of the vehicle outer side of the rocker part inner plate in a present Example. It is CAD data inside the vehicle of the rocker part inner plate in a present Example. It is the evaluation data inside the vehicle of the rocker part inner plate in a present Example. It is CAD data of the vehicle outer side of the rocker part inner side plate in a present Example. It is the evaluation data of the vehicle outer side of the rocker part inner side plate in a present Example.

Explanation of symbols

10 Data converter 11 Computer 11a CPU
11b Storage device 12 Input device 13 Image output device 20 Body data 21 Spatial grid 21a Grid line 21b Boundary surface 22 Obstacle model 30 Inner plate 31 Outer plate 31a Coating hole 32 Electrode 33 DC power supply 50 Parts 51 Drain hole A simple body data B Simplicity body data _H 2 O water OH ^- hydroxide ion R coating RH ^- coating ion

Claims (8)

In the electrodeposition coating method in which the outer plate surface is electrodeposited,
Using the CAD data of the outer plate, the outer plate is combined with a spatial lattice formed at a predetermined pitch, and a calculation model generating step for generating a calculation model of the outer plate on the boundary surface of the spatial lattice;
Using the calculation model, simulation of electrodeposition coating, and a simulation process for determining coating conditions;
An electrodeposition coating step of performing electrodeposition coating based on the coating conditions determined in the simulation step. A coating-coated peripheral hole for electrodeposition coating is formed on the outer plate of the dual structure including the outer plate and the inner plate. After the outer plate surface has been electrodeposition-coated, In the electrodeposition coating method in which the inner plate surface is electrodeposited via,
When the CAD data of the double structure is used to combine the double structure with a spatial lattice formed at a predetermined pitch and generate a calculation model of the double structure on the boundary surface of the spatial lattice In addition, the calculation model generation step of selecting the pitch so that the peripheral hole with the coating film appears on the calculation model diagram,
Using the calculation model, simulation of electrodeposition coating, the simulation step of determining the number or hole position of the peripheral hole with the coating film,
And an electrodeposition coating step of performing electrodeposition coating on the double structure formed with the coating-coated peripheral holes determined in the simulation step as an object to be coated. In the electrodeposition coating method according to claim 1 or claim 2,
Electrodeposition characterized in that the simulation step stores energization amount and basic film thickness data, and energization amount and basic resistance of coating film, and uses these data to simulate electrodeposition coating. How to paint. In the electrodeposition coating simulation program in which the outer plate surface is electrodeposited,
Using the CAD data of the outer plate, combining the outer plate with a spatial lattice formed at a predetermined pitch, and having a calculation model generation step of generating a calculation model of the outer plate on a boundary surface of the spatial lattice. An electrodeposition coating simulation program featuring A coating-coated peripheral hole for electrodeposition coating is formed on the outer plate of the dual structure including the outer plate and the inner plate. After the outer plate surface has been electrodeposition-coated, In the electrodeposition coating simulation program in which the inner plate surface is electrodeposited via
When the CAD data of the double structure is used to combine the double structure with a spatial lattice formed at a predetermined pitch and generate a calculation model of the double structure on the boundary surface of the spatial lattice And a calculation model generation step of selecting the pitch so that the peripheral hole with a coating film appears on a calculation model diagram. In the electrodeposition coating simulation program according to claim 3 or claim 5,
An electrocoating paint simulation program characterized by storing energization quantity and basic film thickness data, and energization quantity and basic coating film resistance data, and using these data to simulate electrocoating. In a surface data generation method for generating surface data of a plate,
Using the CAD data of the plate, combining the plate with a spatial grid formed at a predetermined pitch, and having a calculation model generation step of generating a calculation model of the plate on a boundary surface of the spatial grid, To generate surface data. Surface data generation program for generating surface data of a plate,
Using the CAD data of the plate, combining the plate with a spatial grid formed at a predetermined pitch, and having a calculation model generation step of generating a calculation model of the plate on a boundary surface of the spatial grid, Surface data generation program.

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