JP2007133547A - Dip coating analysis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dip coating analysis device qualitatively analyzing a coating result of dip coating about the dip coating represented by electrodeposition coating, allowing analysis whether an air stagnation or liquid stagnation is generated or not by one process, and capable of performing the easy analysis. <P>SOLUTION: The analysis device includes: an input means input data necessary for the analysis of the dip coating; and a control means dividing image data of a coated work inputted by the input means and in a prescribed range around the coated work into a plurality of elements, and comparing an evaluation value obtained by analyzing a physical amount of a prescribed position of each the divided element by use of a prescribed Laplace equation and a prescribed threshold to predict at least one of the occurrence of the air stagnation and the generation of the liquid stagnation about the coated work. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dip coating analyzer, and more particularly to a dip coating analyzer that analyzes physical quantities using Laplace equations.

  Electrodeposition coating performed by immersing the body of an automobile in an electrodeposition tank filled with an electrodeposition solution can form a coating film substantially uniformly, and is applied to the object to be coated, that is, the welded part of the workpiece to be painted. There are also advantages such as being able to paint. On the other hand, when the work to be painted is a vehicle body, an air pocket called an air pocket occurs in the recesses such as the inner surface of the hood, the inner surface of the roof, and the lower surface of the floor, and a coating film cannot be formed on the portion where the air pool is generated. There is a drawback.

  In view of this, a method has been proposed in which it is determined whether or not air retention occurs when the work to be coated is immersed in an electrodeposition bath. (For example, refer to Patent Document 1).

  In this method, first, each surface of the workpiece to be painted is divided into an arbitrary number of triangular polygons (triangular elements) based on the vertex coordinate data, and the workpiece to be painted is inserted into each triangular polygon (triangular element). It is determined whether or not the surface portion can become an air pool when simulated immersion is performed in the immersion tank in the tank angle posture.

  However, depending on such a method, it is necessary to calculate the state change between the air and the liquid paint in the immersion tank for every element divided into a plurality of elements, which complicates the calculation. For this reason, the load on the computer is increased, and an enormous amount of time is required for the operation. There is a limit to performing the operation using a general-purpose computer such as a personal computer, and there is a problem of lack of practicality. This method is effective when the shape of the workpiece to be analyzed is simple, but when the shape of the part that becomes the blind spot of the workpiece to be analyzed is complicated, an accurate analysis result is obtained. There is also a problem that it may not be obtained.

  Furthermore, when the work to be coated is immersed in the virtual electrodeposition tank, air is trapped in the work to be coated by predicting the behavior of the gas-liquid interface by two-phase fluid analysis of air and liquid paint on the surface of the work to be painted. There has been proposed a method for analyzing whether or not this occurs.

According to such a method, for example, the workpiece α to be coated when the workpiece α to be analyzed is immersed in the electrodeposition tank as shown in FIGS. 12 (a) → (b) (c) → (d). It is possible to accurately understand the behavior of the interface between the air and the liquid paint on the surface. As shown in FIG. 13 (e)->(f)->(g)-> (h), an electrode formed as shown in FIG. The same applies when immersing in the tank.
JP 2000-51750 A

  However, even when the method of predicting the behavior of the gas-liquid interface by the two-phase fluid analysis of the air and liquid paint on the surface of the workpiece to be coated, the behavior of the gas-liquid interface must be calculated from moment to moment, resulting in a large amount of computation. Therefore, the burden on the computer is very large and the calculation time is enormous.

  In addition, when dip coating is performed on a work to be coated, a liquid pool may occur. However, in the conventional method, analysis of whether or not an air pool occurs in one calculation process, and whether or not a liquid pool occurs. Both of the analysis of the failure could not be performed, and it was necessary to perform the analysis in separate calculation steps. Therefore, for the workpiece to be analyzed, in order to analyze the occurrence of air pool and liquid pool, it is necessary to carry out in a separate calculation process, and the trouble of performing the analysis becomes complicated, There was a problem that the analysis cost was soaring.

  These problems occur not only in electrodeposition coating but also in general dip coating.

  It is an object of the present invention to qualitatively analyze the result of dip coating for dip coating typified by electrodeposition coating, and to analyze whether air pools or liquid pools occur in one step In addition, an object of the present invention is to provide an immersion coating analyzing apparatus that can be easily analyzed.

  In order to solve the above-described problem, the dip coating analysis apparatus according to claim 1 includes an input unit that inputs data necessary for dip coating analysis, a workpiece to be coated and a workpiece to be coated that are input by the input unit. Is divided into a plurality of elements, and an evaluation value obtained by analyzing a physical quantity at a predetermined position of each of the divided elements using a predetermined Laplace equation is compared with a predetermined threshold value. And a control means for predicting at least one of the occurrence of air accumulation or liquid accumulation by simulation for the workpiece to be coated.

  The invention according to claim 2 is the dip coating analyzer according to claim 1, wherein the control means evaluates the evaluation value greater than the threshold value when the predetermined threshold value is a positive value. A range of elements having a value is determined that air accumulation has occurred, and when a predetermined threshold value is a negative value, the range of elements having an evaluation value smaller than the threshold value has a liquid pool. It is a feature that determines that it has occurred.

  According to a third aspect of the present invention, in the dip coating analysis apparatus according to the first or second aspect of the present invention, there is provided display means for displaying an analysis process of dip coating by the control means.

  The invention according to claim 4 is characterized in that, in the immersion coating analyzing apparatus according to any one of claims 1 to 3, the physical quantity is a temperature of the liquid paint or a viscosity of the liquid paint. To do.

Further, the invention according to claim 5 is the immersion coating analyzing apparatus according to any one of claims 1 to 4, wherein the Laplace equation is a condition of the following formulas (1) and (2): It is the following formula (3) used below.

  According to the first aspect of the present invention, the two threshold values can be obtained without separately performing the calculation of whether or not the air pool is generated and the analysis of whether or not the liquid pool is generated as in the prior art. By using this, it is possible to analyze whether or not an air pool occurs in the workpiece to be coated and analyze whether or not a liquid pool occurs in one calculation process. Therefore, the analysis cost and the time for performing the analysis can be shortened.

  Further, according to the invention described in claim 1, it is possible to reduce the amount of calculation and reduce the burden on the computer when analyzing dip coating typified by electrodeposition coating. Can be shortened.

  According to the second aspect of the present invention, it is possible to easily and qualitatively determine whether an air pool or a liquid pool occurs in the work to be coated by determining the evaluation value derived previously using a predetermined threshold value. Can be done automatically.

  According to the third aspect of the present invention, the analysis process of the workpiece to be coated can be confirmed, and when an air pool or a liquid pool is generated at any position of the workpiece to be coated, the position can be visually confirmed. Therefore, the efficiency of subsequent design work and the like can be increased.

  Further, according to the invention described in claim 4, since it is possible to perform the analysis using a plurality of types of physical quantities without being limited to a specific physical quantity, the analysis is performed according to the liquid paint to be analyzed and the conditions of the analysis target. Since it is possible to select a physical quantity that can be easily analyzed, analysis can be performed efficiently and easily.

  Further, according to the invention described in claim 5, various physical quantities of the liquid are used by analyzing the physical quantity of the liquid around the workpiece to be coated using the Laplace equation of Formula (3) under a predetermined condition. Thus, it is possible to easily and qualitatively determine whether an air pool or a liquid pool occurs in the workpiece.

  Next, the present 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 workpiece to be coated 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 the workpiece to be coated is liquid. Any coating method may be used as long as it is applied by immersing it in a paint.

  FIG. 1 is a block diagram showing an embodiment of a fluid analysis apparatus 1 for performing immersion coating analysis on the workpiece.

  As shown in FIG. 1, the fluid analysis device 1 of the present embodiment includes a CPU 2, a ROM 3 that functions as a storage area or work area of the CPU 2, and various programs and analyzes for executing the invention according to the present embodiment, for example. A control unit 5 as a control means including a RAM 4 in which target data and the like are stored, a keyboard 6 as an input means, a keyboard controller 9 for controlling the keyboard 6, a display 10 as a display means, and a display 10 A display controller 11 for controlling, a hard disk drive (HDD) 12, a flexible disk drive (FDD) 13, a disk controller 14 for controlling the HDD 12 and the FDD 13, and a network interface controller 16 for connection to the network 15 are provided. Via the system bus 19 is configured to be communicably connected to each other.

  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 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 the processing program to analyze the workpiece to be coated of the present embodiment. Control to realize the operation.

  The control unit 5 analyzes at least one of the occurrence of an air pool or a liquid pool in response to an input signal from the keyboard 6. That is, the control unit 5 can also analyze both the occurrence of the air pool and the occurrence of the liquid pool, and sets which analysis is performed first according to the input signal from the keyboard 6. Is possible.

  The control unit 5 reads the data of the workpiece to be analyzed from the hard disk drive 12 and divides the workpiece into a plurality of elements to construct a three-dimensional numerical calculation model for numerical calculation. ing.

  That is, the control unit 5 sets an analysis target area set in accordance with an instruction signal from the keyboard 6, and, for example, as shown in FIG. Divide into multiple elements. The elements are divided into so-called volume meshes which are three-dimensional elements such as tetrahedrons and hexahedrons, for example. The actual workpiece α to be coated is displayed three-dimensionally on the display 10, but in the present embodiment, it is displayed in two dimensions for convenience.

  Further, when analyzing the work to be coated, the control unit 5 sets a predetermined region including the work to be painted as an analysis target range. There is no particular limitation on the size of the analysis target range, and it is sufficient if the surrounding area is included as well as the work to be painted.

  Further, the control unit 5 selects a physical quantity for analyzing the workpiece to be coated in accordance with an instruction signal from the keyboard 6. Examples of the physical quantity for analyzing the workpiece to be coated include the temperature of the liquid and the viscosity of the liquid.

  Moreover, the control part 5 sets the boundary condition at the time of analyzing the to-be-coated workpiece | work (alpha). The boundary condition is composed of an ambient boundary condition and a boundary condition of the workpiece to be coated.

  The ambient boundary condition means the temperature condition of the entire analysis region. The temperature setting of the entire analysis region is obtained as a function of the coordinate value of the Y axis of each element, that is, the value of the coordinate axis taken in the gravity direction G.

  Specifically, the temperature setting is proportional to the height of the analysis region. For example, in the case of the analysis region as shown in FIG. 2, the upper end temperature is set to be the highest and the lower end temperature is set to be low. The temperature setting in the analysis region is not particularly limited and can be set arbitrarily. In the present embodiment, the upper end temperature is set to 100K (Kelvin) and the lower end temperature is set to 0K (Kelvin).

  In addition, when the viscosity of the liquid is used as the physical quantity, the viscosity of the liquid is increased in proportion to the height of the analysis region, and is set so that the viscosity decreases as the height of the analysis region decreases. .

And the temperature in each height of an analysis field is derived by the following formula (1).

Here, T _V is representative of the temperature of the center of gravity of the element, rather than the temperature of the center-of-gravity point of the actual elements, the temperature of the upper end of the analysis region as described above is the highest, so that the temperature of the lower end is lowered This is the set temperature under the set conditions. M is the maximum temperature set in the analysis region (100K in the present embodiment), Y is the range on the Y axis in the analysis region, and y is the coordinate value on the Y axis of the center of gravity of the element. Each means.

Incidentally, as a physical quantity, in the case of using the viscosity of the liquid, except that T _V is to represent the viscosity of the center-of-gravity point of the element is the same as in the case of using the temperature of the liquid as a physical quantity.

In addition, the boundary condition of the workpiece α to be coated means a condition of heat conduction on the surface of the workpiece α to be coated. In the present embodiment, the boundary condition of the workpiece to be coated is expressed by the following equation (2).

Here, n represents a distance from a predetermined point on the surface of the workpiece α to a predetermined position in the vertical direction, and _TN is a position n away from the predetermined point on the surface of the workpiece α in the vertical direction. Of temperature. Formula (2) means that the heat conduction condition on the surface of the workpiece α to be coated is a heat insulation condition. That is, the member constituting the surface of the workpiece α to be coated indicates that there is no temperature change in the vertical direction from the surface.

In addition, when using the viscosity of a liquid as a physical quantity, it is the same as the case where the temperature of a liquid is used as a physical quantity except that _TN represents the viscosity of the liquid at a position n away from the surface of the work α to be coated. .

  Under these boundary conditions, a temperature contour line (contour line) is displayed as shown in FIG. 3 by connecting the centroid points of elements having a common temperature among the centroid points of the elements in the analysis region. It has become. On the other hand, the contour line of the temperature as shown in FIG. 4 is displayed on the workpiece β in which the vent hole H is formed above.

Further, the control unit 5 calculates the actual temperature of the center of gravity of each element by solving the following Laplace equation (3).

Here, T _R is the actual temperature of the center of gravity of the elements derived by the equation (3), lambda is the thermal conductivity, x is the coordinate value on the X-axis of the center of gravity of the element that is the calculation target, y is The coordinate value on the Y axis of the centroid point of the element to be calculated, and z mean the coordinate value on the Z axis of the centroid point of the element to be calculated.

Incidentally, as a physical quantity, in the case of using the viscosity of the liquid, except that T _R is represent the viscosity of the settings derived by Equation (3) is the same as in the case of using the temperature of the liquid as a physical quantity.

The control unit 5 reads the following equation (4) stored in the storage area, and obtains the evaluation value (f) of the barycentric point of each element by the equation (4).

  Here, Y means the maximum height on the Y axis in the analysis region, and y means the coordinate value on the Y axis of the barycentric point of the element to be calculated. The same applies to the case where the viscosity of the liquid is used as the physical quantity.

  Then, as shown in FIG. 5, the control unit 5 draws a contour line connecting the centroid points of the elements having the same evaluation value f to clarify the distribution of the evaluation value f in the analysis region. ing. On the other hand, in the case of the workpiece β in which the vent hole H is provided at the upper side, contour lines are drawn as shown in FIG.

  Further, the control unit 5 compares the evaluation value f with the threshold value Ψ, and determines whether or not an air pool or a liquid pool occurs in the workpiece α to be analyzed.

  In determining whether or not air accumulation occurs in the work α to be coated, the control unit 5 sets the threshold value Ψ to a positive value Ψa, and air accumulation occurs in a region where f> Ψa. It comes to judge it. The area where it is determined that air is trapped is displayed as a dotted area A on the screen of the display 10 as shown in FIG.

  Since there is no movement of heat in the area where air is accumulated, heat accumulates, so heat accumulation occurs, and the temperature becomes higher than the surroundings. Therefore, the evaluation value f of the element in the range where the heat accumulation actually occurs is checked in advance, and the lowest value among the evaluation values in the area where the heat accumulation occurs is set as the threshold value Ψa, and the evaluation of the value equal to or higher than the threshold value Ψa is performed. The range of the element having the value f is determined as an air reservoir.

  On the other hand, if the workpiece β is analyzed using the threshold Ψa as in the workpiece α, the dotted line area is not displayed as shown in FIG. It is judged not to.

  On the other hand, when determining whether or not a liquid pool occurs for the workpiece α to be coated, the control unit 5 sets the threshold value Ψ to a negative value Ψl and the liquid pool is generated in a region where f <Ψl. It has come to be judged that. The area where it is determined that the liquid pool has occurred is displayed on the screen of the display 10 as a dotted area L1 as shown in FIG.

  On the other hand, when the workpiece β is analyzed using the threshold Ψl in the same manner as the workpiece α, a dotted area L2 is displayed and a liquid pool is generated as shown in FIG. It is judged that

  In the area where the liquid is accumulated, the liquid is moved up the upper surface of the area where the liquid is accumulated, and heat is taken away, so the temperature is lower than the surroundings. Therefore, the evaluation value f of the element in the range in which the liquid pool has occurred is examined in advance, and the highest evaluation value in the region in which the liquid pool has occurred is defined as the threshold value Ψl, and the element having the evaluation value of the threshold value or less is selected. The range is judged to be a liquid pool.

  Note that the threshold value varies depending on the analysis target and the type of paint used for the analysis, and is changed according to the analysis target and the paint.

  Even when the viscosity of the liquid is used as a physical quantity, the threshold value previously derived by the same technique as in the case of the liquid temperature is used by using the evaluation value derived by the same technique as that when the liquid temperature is used as the physical quantity. It is used to determine at least one of whether or not an air pool is generated and whether or not a liquid pool is generated.

  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.

  Data necessary for the present embodiment is input by operating the keyboard 6, but a mouse, a scanner, or the like may be used to input data necessary for the present embodiment. .

  The hard disk drive 12 stores data of a workpiece to be analyzed. The hard disk drive 12 stores the input gravity direction G in a storage area and determines the gravity direction at the time of analysis. The analysis result is stored in the hard disk drive 12, and the result of the analysis already performed can be repeatedly displayed on the display 10.

  Below, with reference to the flowchart of FIG. 11, the analysis of the to-be-painted workpiece | work using the immersion coating analyzer 1 which concerns on this embodiment is explained in full detail. In the following description, it is assumed that the object to be coated α is analyzed whether or not an air pool is generated and whether or not the air pool is generated, and the physical quantity uses the temperature of the liquid.

  First, the shape data of the workpiece to be coated α is input from the keyboard 6 (step S1), and then the liquid temperature is selected as a physical quantity for analyzing the workpiece to be coated α (step S2). Next, the control unit 5 selects the work α to be coated and the space around it as an analysis region, divides the region into three-dimensional elements, and then on the X axis as shown in FIG. The range of 2500 mm and 2500 mm on the Y axis is displayed on the display 10 (step S3). Next, the gravitational direction G in the analysis region is set along the Y axis and in the lower end direction of the analysis region (step S4).

Thereafter, boundary conditions are set (step S5). In setting the boundary condition, first, M in the following expression (1) is set to 100K which is the maximum temperature in the analysis region, Y is set to 2500 mm which is the range on the Y axis of the analysis region, and y is the center of gravity of each element. enter the coordinate values on the Y-axis of the point, asking the temperature T _V of the setting of the center-of-gravity point of each element, it sets the ambient boundary conditions.

Next, boundary conditions for the workpiece α to be coated are set. As shown in the following formula (2), the boundary condition of the workpiece α to be coated is that the thermal conduction condition of the surface of the workpiece α is an adiabatic condition, that is, the members constituting the surface of the workpiece α to be coated are Suppose that there is no temperature change in the vertical direction from the surface.

  Under these boundary conditions, the contour lines of the temperature as shown in FIG. 3 are drawn by connecting the centroid points of the elements having the common temperature among the centroid points of the elements in the analysis region.

Then, the control unit 5 calculates the actual temperature T _R by solving the equation (3) below in the center of gravity of each element (step S6).

Then, by substituting the actual temperature T _R of the center-of-gravity point of the elements in the equation (4) below to calculate the evaluation value f, in the analysis region, signed a centroid of elements having the same evaluation value f, FIG. As shown in FIG. 5, a contour line connecting the centroid points of elements having the same evaluation value f in the analysis region is drawn to clarify the distribution of the evaluation value f (step S7).

  Next, the type and order of analysis are selected (step S8). If the type of analysis selected is an air pool or a liquid pool, and it is selected that the analysis of the air pool will be performed first and the analysis of the liquid pool will be performed later in the order of analysis, An analysis is performed as to whether or not air accumulation occurs in the work α (step S9). The analysis of whether or not an air pool has occurred uses a positive threshold value Ψa, determines that the range having a value larger than Ψa is the range in which the air pool has occurred, and that an air pool has occurred The determined range is displayed as a region A with a dotted line drawn on the screen of the display 10 as shown in FIG.

  When the analysis on whether or not the air pool is generated is completed, an analysis is performed on whether or not a liquid pool is generated in the workpiece α to be coated (step S10). In the analysis of whether or not the liquid pool occurs, a negative threshold value Ψl is used, and a range having a value smaller than Ψl is determined as a range where the liquid pool is generated, and the range is shown in FIG. This is displayed as a region L1 indicated by a dotted line on the screen of the display 10. Then, the analysis ends (END).

  As described above, according to the invention according to the present embodiment, as in the conventional case, the analysis of whether or not the air pool occurs and the analysis of whether or not the liquid pool occurs are performed separately. Instead, by using two threshold values, it is possible to analyze whether or not an air pool occurs in the workpiece to be coated and whether or not a liquid pool occurs in one calculation process. Therefore, the analysis cost and the time for performing the analysis can be shortened.

  Further, when analyzing dip coating typified by electrodeposition coating, the amount of calculation can be reduced, the burden on the computer can be reduced, and the calculation time can be shortened compared to the conventional case.

It is a schematic block diagram of a fluid analyzer. It is the figure which divided | segmented the analysis area | region containing a to-be-coated workpiece into several elements. It is a figure showing the temperature distribution in the analysis area | region containing the to-be-painted workpiece | work (alpha). It is a figure showing the temperature distribution in the analysis area | region containing the to-be-coated workpiece (beta). It is a figure showing the state which connected the gravity center point of the element which has the same evaluation value f in the analysis area | region containing the to-be-painted workpiece | work (alpha) with the line. It is a figure showing the state which connected the barycentric point of the element which has the same evaluation value f in the analysis area | region containing the to-be-painted workpiece | work (beta) with the line. It is a figure showing the analysis result of whether the air pocket has generate | occur | produced in the to-be-painted workpiece | work (alpha). It is a figure showing the analysis result of whether the air pocket has generate | occur | produced in the to-be-coated workpiece (beta). It is a figure showing the analysis result of whether the liquid pool has generate | occur | produced in the to-be-coated workpiece | work (alpha). It is a figure showing the analysis result of whether the liquid pool has generate | occur | produced in the to-be-coated workpiece (beta). It is a flowchart of the analysis of the dip coating which concerns on this embodiment. (A)-(d) is the figure showing the state by which the to-be-coated work (alpha) is immersed in a liquid coating material. (E) to (h) are views showing a state in which the work β to be coated is immersed in the liquid paint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluid analyzer 5 Control part 6 Keyboard 9 Keyboard controller 10 Display 11 Display controller 12 Hard disk drive 13 Flexible disk drive 14 Disk controller 15 Network 16 Network interface controller 19 System bus

Claims (5)

An input means for inputting data necessary for the analysis of immersion coating;
The workpiece and the image data of a predetermined range around the workpiece to be coated input by the input means are divided into a plurality of elements, and a physical quantity at a predetermined position of each of the divided elements is expressed by a predetermined Laplace equation. A control means for predicting at least one of the occurrence of an air pool or a liquid pool in the simulation by comparing the evaluation value analyzed using and a predetermined threshold;
An immersion paint analyzing apparatus comprising: The control means includes
When the predetermined threshold value is a positive value, it is determined that the range of elements having an evaluation value that is higher than the threshold value has an air reservoir,
2. The dip coating according to claim 1, wherein when the predetermined threshold value is a negative value, it is determined that a range of elements having an evaluation value smaller than the threshold value has a liquid pool. Analysis device.   The dip coating analysis apparatus according to claim 1, further comprising display means for displaying an analysis process of dip coating by the control means.   4. The immersion coating analyzing apparatus according to claim 1, wherein the physical quantity is a temperature of the liquid paint or a viscosity of the liquid paint. 5. 5. The Laplace equation is the following equation (3) used under the conditions of the following equations (1) and (2): 5. Immersion paint analyzer.

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