JPH09150443A - Apparatus for analyzing fluid-flow process and manufacture of injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To faithfully reproduce the shape of the flow path of a fluid by using a three-dimensional model by determining flow conductance of the fluid in a narrow width part of a cavity based on the thickness of the narrow width part and obtaining pressure of the fluid in each microelement by the flow conductance. SOLUTION: Thickness of a product of a thin thickness part divided into three-dimensional microelements is set (S3) and the flow conductance K in each microelement is determined (S4). Then, by utilizing the flow conductance K, pressure of an injection molding material in each microelement is obtd. (S5) and graphic processing of it is performed and is displayed by a style of a contour line or a graph (S6). In addition, the obtd. change in pressure is evaluated (S7) and if a result where it is estimated that injection molding can be well performed is obtd., injection molding is performed under the condition of the injection molding to prepare an injection molding (S9). It is possible thereby to faithfully reproduce the shape of a cavity by using a three- dimensional model.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analyzer for obtaining the distribution of pressure or pressure change or flow velocity of a fluid in a fluid flow process, and analyzing the fluid flow process by the analysis device.
An analysis method, an analysis apparatus that applies these devices or methods to an injection molding process, a method for determining injection molding conditions using the analysis method and an analysis method for such an injection molding process, and a method for manufacturing an injection molded product Related to injection molded products.

[0002]

2. Description of the Related Art Generally, an analysis method such as an injection molding process for reproducing a fluid flow process including an injection molding process by computer simulation has been widely put into practical use. Hereinafter, as a specific example of the analysis method of the fluid flow process, the analysis method of the injection molding process will be mainly described.

These methods of analyzing the injection molding process have contributed to higher quality, higher efficiency and lower cost in product development of injection molded products and the like. Regarding the utilization method, etc., for example, JP-A-3-224712 and JP-A-4-15.
It is disclosed in Japanese Patent Application Laid-Open No. 2120, Japanese Patent Application Laid-Open No. 4-305424, Japanese Patent Application Laid-Open No. 4-331125 and the like. In each of the injection molding process analysis methods, a change in pressure, temperature, shear stress, or the like at each part is obtained using a two-dimensional model.

In these conventional methods for analyzing the injection molding process and the like, a two-dimensional model is used as a model of a cavity into which a fluid flows (a model of a mold having the same shape as an injection molded product). Each part of is divided into a number of two-dimensional microelements such as triangles or quadrilaterals, and a numerical analysis method by a computer is used to obtain changes in pressure, temperature, or shear stress in each microelement.

According to the conventional method of analyzing the injection molding process, when the shape of the cavity can be approximated by a combination of two-dimensional figures, such as when the thickness of the cavity is smaller than the overall size of the cavity, a highly accurate analysis result is obtained. Can be obtained.

However, in the case of a product having a wall thickness of more than 5 mm or a small molded product such as a connector having a small overall size, the effect of three-dimensional flow such as flow in the wall thickness direction appears strongly, and therefore the accuracy of the conventional analysis method is high. I couldn't analyze it well. In addition, even in the case of thin-walled molded products, in order to accurately analyze the local flow state such as steps and corners, most useful information cannot be obtained by the conventional method using planar elements. It was

Therefore, as used in a general numerical analysis method represented by the finite element method or the like, the inside of the cavity is modeled by using a minute element having a three-dimensional shape (three-dimensional model). Attempts have also been made to obtain high accuracy.

However, in general, in order to obtain an accurate solution using a three-dimensional model, it is necessary to divide the inside of the cavity into small pieces using a large number of minute elements. This is because, according to a numerical analysis method that generally divides a shape into minute elements and analyzes it, the distribution of the physical quantity such as the pressure inside each minute element is expressed by a simple function approximation such as linear approximation. This is because fine minute element division is required to approximate a steep region with a simple function. In particular, since there is a large difference in speed between the portion in contact with the surface of the mold and the central portion of the thickness, it is preferable to divide the minute element into four or more layers in the thickness direction, if possible, for accurate analysis.

This tendency becomes more remarkable as the thickness of the molded product becomes thinner, but it is difficult to create an analytical model for dividing the thickness direction of a thin molded product having a complicated shape such as ribs, steps, or curved surfaces into multiple layers. Takes a long time. In addition, the model created in this way contains a large number of minute elements, and requires a huge amount of time for analysis, which is not practical. That is, in an injection-molded product having a complicated shape having both a thin portion and a thick portion, it was difficult to divide the whole into three-dimensional minute elements for analysis.

Therefore, when a thin portion and a thick portion coexist in the same molded product, it is possible to divide the thin portion into a two-dimensional model and the thick portion into a three-dimensional model. However, such a mixed type model has a connection state in which the connection between the two-dimensional microelements and the three-dimensional microelements is significantly different from the actual shape.

That is, at the connecting portion between the thin wall portion and the thick wall portion, the entire thin section of the thin wall portion microelement should originally be connected to the thick wall portion, but in the mixed type model, a two-dimensional element Only the edges, that is, the sides of the triangle or the quadrangle, are connected to the thick portion. For this reason, in the mixed type, there is a possibility that the analysis accuracy may decrease near the connection part.

For example, in the case of a molded product in which a thin portion and a thick portion are mixed as shown in FIG. 11, a combination of conventional two-dimensional minute elements and three-dimensional minute elements as shown in FIG. When expressed by, the analysis accuracy in the vicinity of the connecting portion between the two is reduced.

This situation will be described with reference to FIGS. 17, 18 and 19. FIG. 18 shows the flow of material fluid obtained when a model is constructed by dividing the whole including the thin portion 201 into three-dimensional minute elements, and FIG. 19 shows the thin portion 204 as a two-dimensional minute element. Shows the case of division into. The actual flow of the fluid is as shown in FIG.
As shown in, the fluid 203 flowing from the thin portion 204 to the thick portion 202 flows in the direction along the surface of the thin portion 201 at the central portion of the thickness. Therefore, the modeling of FIG. 18 is likely to give the correct result. On the other hand, in the modeling of FIG. 19, as shown in FIG.
5 and the thick-walled microelements 24 are two-dimensional microelements 25.
Since the edges are in contact with each other only at the edge 26, it is easy to produce an analysis result that the fluid flows radially as shown by 206 in FIG. This is different from the fact, and for example, the result is that the surface appearance of the injection-molded product is impaired because the fluid flow collides with the wall surface of the molding die at an angle close to vertical at the corner of the thick wall. This may cause the molding conditions to be erroneously determined to be unsuitable for molding.

Further, in order to obtain a certain level of analysis accuracy in the mixed type model, special knowledge and technology are required for model creation, such as which part should be modeled by a two-dimensional element.

Further, even if the entire molded product has a thin shape, it has been difficult to utilize CAD (Computer Aided Design) data used in product design for analysis in order to reduce the effort of shape input. That is, in the conventional two-dimensional analysis method, the three-dimensional CAD data cannot be directly used as the basic data for modeling, and the wall thickness neutral plane (the set of intermediate points in the wall thickness direction of each part of the thin wall portion) It was necessary to redefine the virtual surface consisting of () and recreate the shape. Even in the case of the mixed model, it is necessary to redefine the wall thickness neutral plane for the two-dimensional element part as in the conventional method, so that it takes a lot of time and effort to create the analysis model and the analysis period becomes long. Another problem is that it requires an operator who is skilled in defining the shape.

[0016]

The first object of the present invention has been made in view of the above problems, and in particular, a three-dimensional model is used in the analysis of a fluid flow process flowing in a cavity including a narrow region. An object of the present invention is to provide an analysis apparatus and an analysis method for a fluid flow process that faithfully reproduces the shape of a fluid flow path by using, and realizes accurate analysis within a practical calculation time.

A second object of the present invention is to faithfully reproduce the shape of the molded product by using a three-dimensional model in the analysis of the injection molding process of the injection molded product including the thin-walled portion, and to use it in practice. An object of the present invention is to provide an analysis device and an analysis method of an injection molding process that realizes a precise analysis within a specific calculation time.

A third object of the present invention is to use the analyzer for the injection molding process to design the product shape, mold design,
An object of the present invention is to provide a method for efficiently producing a high-quality injection-molded product by determining injection-molding conditions such as material selection.

[0019]

A device for analyzing a fluid flow process according to the present invention comprises a three-dimensional model construction means for constructing a three-dimensional model in which at least a part of a cavity in which a fluid flows is divided into a large number of minute elements. , The flow conductance κ of the fluid in each of the microelements belonging to the narrow portion of the cavity is determined based on the thickness of the narrow portion, while the microelement in each of the microelements belonging to the wide portion of the cavity is Flow conductance determining means for determining the flow conductance κ of the fluid so that the fluid conductance κ has a small value when the position is close to the cavity wall surface, and has a large value when the position is far from the cavity wall surface; Pressure calculation means for calculating the pressure of the fluid in each of the minute elements based on the flow conductance κ. It is a symptom.

Another aspect of the apparatus for analyzing a fluid flow process of the present invention is a three-dimensional model construction means for constructing a three-dimensional model in which at least a part of a fluid flow cavity is divided into a large number of minute elements, and The fluid flow conductance κ of the fluid in each of the minute elements belonging to the narrow portion of the cavity
Is determined based on the thickness of the narrow portion, and on the other hand, in each of the minute elements belonging to the wide portion of the cavity, the flow conductance of the fluid is set to be a small value when the minute element is close to the cavity wall surface. Flow conductance determining means for determining κ and determining the flow conductance κ of the fluid so as to be a large value at a distant position, and a pressure for obtaining a pressure change of the fluid in each of the minute elements based on the flow conductance κ. And a change calculation means.

Another aspect of the fluid flow analysis apparatus of the present invention is a three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of a cavity in which a fluid flows is divided into a large number of minute elements, and The fluid flow conductance κ of the fluid in each of the minute elements belonging to the narrow portion of the cavity
Is determined based on the thickness of the narrow portion, and on the other hand, in each of the minute elements belonging to the wide portion of the cavity, the flow conductance of the fluid is set to be a small value when the minute element is close to the cavity wall surface. Flow conductance determining means for determining κ and determining the flow conductance κ of the fluid so as to have a large value at a distant position, and a flow for determining the flow velocity of the fluid in each of the minute elements based on the flow conductance κ It is characterized by comprising a speed calculation means.

The method for analyzing a fluid flow process according to the present invention constructs a three-dimensional model in which at least a part of a cavity through which a fluid flows is divided into a large number of microelements, and the fluid flow conductance κ of each microelement is calculated. It is determined based on the flow thickness of the cavity in each micro element, the pressure of the fluid in each micro element is obtained based on the obtained flow conductance κ, and the flow process of the fluid is determined by the obtained pressure. Characterized by analysis.

Another aspect of the method for analyzing a fluid flow process of the present invention is to construct a three-dimensional model in which at least a part of a fluid flow cavity is divided into a large number of microelements, and The flow conductance κ is determined based on the flow thickness of the cavity in each of the microelements, the pressure change of the fluid in each of the microelements is obtained based on the obtained flow conductance κ, and the obtained pressure change is used. It is characterized in that the flow process of the fluid is analyzed.

Another aspect of the method for analyzing a fluid flow process according to the present invention is to construct a three-dimensional model in which at least a part of a cavity in which a fluid flows is divided into a large number of microelements, and in each of the microelements of the fluid. The flow conductance κ is determined based on the flow thickness of the cavity in each micro element, the flow velocity of the fluid in each micro element is determined based on the obtained flow conductance κ, and the obtained flow velocity It is characterized in that the flow process of the fluid is analyzed.

In the injection molding process analyzing apparatus of the present invention, at least a part of the injection molded product is divided into a large number of minute elements.
A three-dimensional model constructing means for constructing a three-dimensional model, and the flow conductance κ of the injection molding material in each of the minute elements belonging to the thin-walled portion of the injection-molded product is determined based on the thickness of the thin-walled portion, while the injection molding is performed. The flow conductance κ of the injection molding material is determined so as to have a small value when the microelements are located close to the surface of the mold in each of the microelements belonging to the thick portion of the product, and a large value is located when the microelements are located far from the mold. A flow conductance determining means for determining the flow conductance κ of the injection molding material so as to obtain, and a pressure calculating means for determining the pressure of the injection molding material in each of the minute elements based on the flow conductance κ. It has a feature.

Another aspect of the injection molding process analyzing apparatus of the present invention is a three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of an injection molded article is divided into a large number of minute elements, and the injection molded article. The flow conductance κ of the injection molding material is determined on the basis of the thickness of the thin-walled portion in each of the micro-elements belonging to the thin-walled portion of The flow conductance κ of the injection molding material is determined so that the value is small when the position is close to the surface of the mold, and the flow conductance κ is determined so that the value is large when the position is far from the mold surface. A determination means and a pressure change calculation means for determining a pressure change of the injection molding material in each of the minute elements based on the flow conductance κ. It is characterized in that it comprises Te.

Another embodiment of the injection molding process analyzing apparatus of the present invention is a three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of an injection molded article is divided into a large number of minute elements, and the injection molded article. The flow conductance κ of the injection molding material is determined on the basis of the thickness of the thin-walled portion in each of the micro-elements belonging to the thin-walled portion of The flow conductance κ of the injection molding material is determined so that the value is small when the position is close to the surface of the mold, and the flow conductance κ is determined so that the value is large when the position is far from the mold surface. And a flow velocity calculation unit for determining a flow velocity of the injection molding material in each of the minute elements based on the flow conductance κ. It is characterized in that it comprises Te.

A preferred embodiment of the injection molding process analyzing apparatus of the present invention is characterized in that the three-dimensional model constructing means constructs a three-dimensional model based on CAD data or CAD surface data of an injection-molded article. There is.

In the method of analyzing the injection molding process of the present invention, at least a part of the injection molded product is divided into a large number of minute elements.
A dimensional model is constructed, the flow conductance κ of the injection molding material in each of the microelements is determined based on the flow thickness of the injection-molded article in each of the microelements, and each of the microscopic values is obtained based on the obtained flow conductance κ. The pressure of the injection molding material in the element is obtained, and the injection molding process of the injection molded article is analyzed by the obtained pressure.

Another aspect of the method for analyzing the injection molding process of the present invention is to construct a three-dimensional model in which at least a part of an injection molded product is divided into a large number of microelements, and to flow the injection molding material in each of the microelements. Conductance κ is determined based on the flow thickness of the injection molded article in each of the microelements,
It is characterized in that a pressure change of the injection molding material in each of the minute elements is obtained based on the obtained flow conductance κ and the injection molding process of the injection molded article is analyzed by the obtained pressure change.

Another aspect of the method for analyzing the injection molding process of the present invention is to construct a three-dimensional model in which at least a part of an injection-molded product is divided into a large number of microelements, and flow the injection molding material in each of the microelements. Conductance κ is determined based on the flow thickness of the injection molded article in each of the microelements,
The flow velocity of the injection molding material in each of the minute elements is obtained based on the obtained flow conductance κ, and the injection molding process of the injection molded article is analyzed by the obtained flow velocity.

Another aspect of the injection molding process analysis method of the present invention is to construct a three-dimensional model in which at least a part of an injection molded product is divided into a large number of microelements, and to belong to the thin-walled portion of the injection molded product. The flow conductance κ of the injection molding material in each micro element is determined based on the thickness of the thin portion, while the flow conductance κ of each micro element belonging to the thick portion of the injection molded product is It increases as the shortest distance R to the mold surface increases,
And, the pressure of the injection molding material in each of the microelements is determined by the function F (R, η) that decreases with the increase of the material viscosity η of the injection molding material and the obtained flow conductance κ. It is characterized in that the injection molding process of the injection-molded article is analyzed based on the obtained pressure.

Another aspect of the injection molding process analysis method of the present invention is to construct a three-dimensional model in which at least a part of an injection molded product is divided into a large number of microelements, and to belong to the thin-walled portion of the injection molded product. The flow conductance κ of the injection molding material in each microelement is determined based on the thickness of the thin portion, while the flow conductance κ in each microelement belonging to the thick portion of the injection molded product is expressed by

(Equation 2) (Η represents the material viscosity of the injection molding material, x, y and z represent the positions of the microelements), and
The pressure of the injection molding material in each of the minute elements is obtained based on the obtained flow conductance κ, and the injection molding process of the injection molded article is analyzed by the obtained pressure.

In the method for producing an injection-molded product according to the present invention, the injection-molding conditions for the injection-molded product are determined, a three-dimensional model in which at least a part of the injection-molded product is divided into a large number of minute elements is constructed, and the injection molding is performed. The flow conductance κ of the injection molding material is determined based on the thickness of the thin portion in each of the microelements belonging to the thin portion of the article, while the microelement is included in each of the microelements belonging to the thick portion of the injection molded article. When is close to the surface of the mold, the flow conductance κ of the injection molding material is determined to be a small value, and when located at a distant position, the flow conductance κ of the injection molding material is determined to be a large value, The pressure of the injection molding material in each of the minute elements is obtained based on the obtained flow conductance κ, and the final injection molding conditions are determined based on the obtained pressure distribution. And it is characterized in that the production of injection-molded article based on the final determined injection-molding conditions.

Another embodiment of the method for producing an injection-molded product according to the present invention is to define injection-molding conditions for the injection-molded product and construct a three-dimensional model in which at least a part of the injection-molded product is divided into a large number of minute elements. , The flow conductance κ of the injection molding material in each of the minute elements belonging to the thin portion of the injection molded product.
Is determined based on the thickness of the thin-walled portion, and on the other hand, in each of the minute elements belonging to the thick-walled portion of the injection-molded product, when the minute element is close to the surface of the mold, injection is performed so as to have a small value. The flow conductance κ of the molding material is determined, and the flow conductance κ of the injection molding material is determined so that the flow conductance κ has a large value at a distant position, and the injection molding in each of the microelements is performed based on the obtained flow conductance κ. It is characterized in that the pressure change of the material is obtained, the injection molding condition is finally determined based on the obtained distribution of the pressure change, and the injection molded product is manufactured based on the finally determined injection molding condition.

Another aspect of the method for producing an injection-molded product according to the present invention is to define injection-molding conditions for the injection-molded product and construct a three-dimensional model in which at least a part of the injection-molded product is divided into a large number of minute elements. , The flow conductance κ of the injection molding material in each of the minute elements belonging to the thin portion of the injection molded product.
Is determined based on the thickness of the thin-walled portion, and on the other hand, in each of the minute elements belonging to the thick-walled portion of the injection-molded product, when the minute element is close to the surface of the mold, injection is performed so as to have a small value. The flow conductance κ of the molding material is determined, and the flow conductance κ of the injection molding material is determined so that the flow conductance κ has a large value at a distant position, and the injection molding in each of the microelements is performed based on the obtained flow conductance κ. The method is characterized in that a flow velocity distribution of a material is obtained, injection molding conditions are finally determined based on the obtained flow velocity distribution, and an injection molded product is manufactured based on the finally determined injection molding conditions. .

In a preferred embodiment of the method for producing an injection-molded article of the present invention, the injection-molding conditions are the shape of the injection-molded article,
It is characterized in that it includes any one of a mold shape, a material injection speed, a material temperature, a mold temperature and an injection molding material.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of a preferred embodiment of an injection molding process analysis apparatus and analysis method, which is an example of a fluid flow process analysis apparatus and analysis method according to the present invention, will be described in detail with reference to the drawings. To do. An example of a preferred embodiment of the method for manufacturing an injection-molded article will be described together.

FIG. 1 is a diagram showing a hardware configuration example of an injection molding process analyzing apparatus of the present invention. Computer 1
An input device 103, a display device 104, and an auxiliary storage device 102 are connected to 01. By the input device 103,
For example, the input of the injection molding condition of the injection molded product to be analyzed and the data of the three-dimensional model are accepted, and such data is stored in the auxiliary storage device 102. The computer 101 stores this data in the internal RA according to the operator's instruction.
It is read into M (random accessible volatile memory) and analyzed. The obtained analysis result is displayed on the display device 104, for example. If necessary, the operator can change the injection molding conditions and perform the analysis again. Further, the output of the analysis result may be performed to a separately prepared printer device or may be stored in the auxiliary storage device 102. In this case, for example, this output can be used as input data of another analysis device.

FIG. 2 shows an injection molding process analyzing apparatus according to the present invention.
It is the flowchart which showed the example of the procedure in the analysis method and the manufacturing method of the injection molded article using such an analysis device.

In the analysis of the injection molding process, first, the injection molding conditions of the injection molded product (for example, the shape of the injection molded product, the mold shape, the material injection speed, the material temperature, the mold temperature or the injection molding material, etc.) are input. (Step 1). Next, the shape is divided into three-dimensional minute elements as shown in FIG. 6, for example, to construct a three-dimensional model of the product (step 2).

Next, the product thickness of the thin portion divided into three-dimensional minute elements is set (step 3). Next, the flow conductance κ in each microelement is determined (step 4). Subsequently, the flow conductance κ of each microelement determined in step 4 is used to obtain the pressure of the injection molding material in each microelement (hereinafter referred to as “material pressure”) (step 5). Here, the change in pressure of each minute element may be obtained. Alternatively, the flow velocity of the injection molding material in each minute element may be directly obtained from the obtained material pressure distribution. The analysis result thus obtained is subjected to, for example, graphic processing and displayed in the form of contour lines or graphs (step 6). You may output to a printer apparatus etc. as mentioned above.

Further, in the case of manufacturing an injection-molded article by using the analysis result of the injection molding process, the pressure, the pressure change or the flow rate obtained as described above is evaluated (step 7). This evaluation is performed, for example, by determining that there is a high possibility that molding failure will occur if there is a region where an abnormal pressure, pressure change, or flow velocity is obtained. If a molding failure is predicted from the obtained analysis result, the injection molding conditions are changed (step 8), and the procedure returns to step 1 for analysis. If these steps are repeated and the result that the injection molding is expected to be performed well is obtained, the injection molding is performed under the injection molding conditions,
An injection molded article is manufactured (step 9).

As a method for constructing a three-dimensional model, shape data may be manually input by an operator, but it is preferable to use CAD data used when designing an injection molded product. In this case, CAD stereoscopic information data may be used or surface data may be used. The three-dimensional information data is data including detailed information such as a procedure for designing with CAD, various points, curves, surfaces (surfaces), volumes, and the like, and has a format defined for each CAD device. On the other hand, the surface data is obtained by extracting only the shape data of the outer surface from the above-mentioned stereoscopic information, and many CAD devices have a function of outputting this as surface data. Examples of the surface data include STL format data used in a stereolithography method for producing a model having the shape from electronic shape information such as CAD using a photocurable resin or the like. The STL format data is data in which a solid surface shape such as a curved surface is approximated by a set of triangles and the vertex coordinates of each triangle are output. In the case of normal CAD data, the data compatibility between softwares is low especially for stereoscopic information, and even if the same software is used, it may be different depending on the version, and the handling is often complicated. In this regard, surface data is generally
Relatively simple and easy to handle. It is preferable that the three-dimensional shape of the cavity is determined using the CAD data, surface data, etc., and the decomposition into minute elements is automatically performed by a preprocessor or the like of a device that calculates by the finite element method.

Next, a method for obtaining the material pressure, the pressure change and the flow velocity in each minute element will be described in detail.

As a method for obtaining the material pressure in injection molding, generally known continuous equation (1) is used. Equation (1) is an equation that expresses that the sum of the inflow rate and the outflow rate to an arbitrary region in the fluid is zero, and is established by assuming that the fluid is incompressible. If the fluid has compressibility, the right side is non-zero, but the following arguments hold in the same way.

[0047]

(Equation 3) Where x, y, z are three-dimensional spatial coordinates, and U, V
, W is the flow velocity of the injection molding material in each coordinate axis direction. This equation 1 is an equation with U, V, and W as unknown variables, and it is generally said that it is necessary to solve this equation and the equation of motion with unknown variables of pressure P and shear stress derived from the flow velocity. When dealing with dimensional flow, there are four unknown variables.

In solving this equation (1), the following equation
By using (2), the flow velocity in each direction U, V, W
By eliminating Eq. (1) from Eq. (1) and reducing the number of unknown variables from four to only one pressure, the calculation time can be significantly reduced. In this case, the calculation time when the three-dimensional model is used can be reduced to about 1/16 and the required RAM capacity of the computer can be reduced to about 1/4. This made it possible for the first time to analyze a three-dimensional injection molding process with practical speed and accuracy.

[0049]

(Equation 4) In equation (2) above, κ is the flow conductance.
This equation (2) is called the Darcy flow equation and represents the permeation flow in a porous medium. That is, three-dimensional coordinate axes x and y
It is assumed that the flow velocities U, V, W in the z, z direction are proportional to the pressure gradient in each direction.

By substituting equation (2) into equation (1), the following equation
(3) is obtained.

[0051]

(Equation 5) Equation (3) is isomorphic to the general equation for heat conduction. In the heat conduction problem, if the temperature T or the temperature gradient at the region boundary is set as a boundary condition in advance for a region divided into arbitrary minute elements, the temperature distribution inside the region can be calculated by the finite element method, difference method, control volume method, and other numerical values. It can be obtained by an analytical method. Therefore, if the pressure P or pressure gradient at the region boundary is set as a boundary condition for a region divided into arbitrary minute elements, equation (3) can also be solved by using an analysis method or analysis program for the heat conduction problem. It is possible to determine the pressure distribution of the material.

Regarding the method of setting the boundary condition, for example, the pressure gradient value obtained from the injection pressure value or the injection flow rate is set in the material inflow portion, and there is no inflow / outflow at the area boundary in contact with the surface of the molding die. Is set, and the pressure at the free end of the flow, which is the free surface, is set to atmospheric pressure, for example.

Further, in the injection molding, the filling portion of the material increases with time, so that the pressure distribution also changes with time. Such a temporal change in the pressure distribution (distribution of pressure change) can be obtained by finding the change in the shape of the filling region according to the total amount of newly filled material and solving the equation (3) again. The control volume method and the FAN method (Flow Analysis Network Method), which are used in the conventional analysis method of the injection molding process, are used to determine the change in the shape of the filling region.
d) etc. are used.

The flow velocity can be easily obtained by, for example, obtaining the pressure distribution P as described above and substituting it into the equation (1).

Next, the method of determining the flow conductance κ in step 4 of FIG. 2 will be described in detail.

First, a method for obtaining the flow conductance κ of the thin portion will be described.

Even when three-dimensional modeling is performed, in a thin portion whose thickness is much smaller than that of the thick portion, the minute elements constituting the portion have a single layer structure as shown in FIG. (When the minute element has a shape of a three-sided pyramid, it means a structure in which one surface of the three-sided pyramid and a vertex not included in the surface are in contact with the cavity at the same time. A two-layered layered structure refers to a structure in which the facing surfaces of the microelements are in contact with the cavity, respectively. It refers to the structure that is in contact with the cavity.
This is because when the portion is attempted to be decomposed into a multi-layer (for example, four or more layers) structure of minute elements or a pure three-dimensional structure similar to a general thick portion, in the thick portion,
This is because this part is decomposed into minute elements that are unnecessarily small, resulting in a model consisting of a very large number of minute elements, which makes analysis impossible in a practical calculation time.

In particular, when a preprocessor for automatically dividing a molded product into a large number of three-dimensional minute elements to create a three-dimensional model is used, the thin-walled portion is often divided into one or two layers. Often. In such a case, in step 3 of FIG. 2, the wall thickness of the thin portion is calculated, and in step 4, the flow conductance κ of this region is calculated by the following equation (4).

[0059]

(Equation 6) Here, H is the thickness of the material channel, and η is the material viscosity.

As a method for setting the wall thickness in step 3, for example, the following method can be considered.

(1) A method using the thickness data of the three-dimensional CAD data of the thin portion. In this method, it is particularly effective for a portion where the wall thickness is set by three-dimensional CAD,
Accurate wall thickness can be set.

(2) A method of separately inputting thickness data for the three-dimensional microelements of the thin portion. Although this method requires time and effort for input, it is possible to reliably select the thin element.

(3) Regarding the three-dimensional microelements in the thin portion, for example, in the case of a thin-walled portion having a one-layer structure, when the three-dimensional microelements have a triangular pyramid shape, they are exposed on the surface (contact with a mold or a cavity). Triangle area S and triangle pyramid volume V
To calculate the wall thickness H = 3V / S. If two or more surfaces of a three-dimensional element are exposed on the surface,
Find H and adopt their minimum. in this way,
The wall thickness can be calculated automatically. When the three-dimensional minute element has a hexahedral shape, the area S of the surface exposed on the surface and the hexahedral volume V are calculated, and H = V / S. When multiple surfaces are exposed on the surface, the same calculation is performed for each exposed surface and the average value is used. In the case of a layered structure of two or more layers, the layer thickness is calculated for each layer and added.

(4) As for the three-dimensional microelements of the thin portion, the normal of the surface exposed on the surface is assumed, and the distance that this normal passes through the model of the thin portion (the normal is the exposed surface). The distance between the point of intersection and the point of intersection of the thin wall portion facing the surface and the surface of the model) is defined as the wall thickness. In this case, since it is obtained based on the surface exposed on the surface of the microelement, it is superior to the method (3) in that it is not affected even if the microelement has a crushed shape.

(5) Using the above-mentioned surface data output from the CAD used to define the cavity shape,
Similar to (4), the wall thickness is the distance that the surface normal of the thin portion passes through the model. As mentioned above, many CAs
The D device has a function of outputting the three-dimensional shape of the surface of the three-dimensional cavity particularly as surface data, and as described above, the surface data is relatively simple,
Often easy to handle.

Next, an example of a method for obtaining the flow conductance κ of the thick portion will be described.

According to the knowledge of the inventor of the present invention, the fluidity of the injection molding material is higher as the distance from the surface of the mold is higher and lower as the distance is closer. Therefore, in general, it is preferable to determine the flow conductance to have a small value when the minute element is located close to the surface of the mold (that is, the cavity wall surface), and to have a large value when the minute element is located far away. Therefore, it is possible to obtain a good approximation to the analysis result by assuming that the flow conductance κ changes according to a function showing such a tendency. That is, it is preferable to use the following equation (5) as the flow conductance κ in such a case.

[0068]

(Equation 7) Here, R is the shortest distance from the center of gravity of each microelement to the mold surface or the shortest distance from each microelement vertex to the mold surface, and η is the material viscosity.

As the function F of the equation (5) is farther from the surface of the mold, that is, the larger R is, the effect of the frictional force between the mold and the material is decreased, so that the flow conductance κ is increased,
Also, as the material viscosity η is larger, the fluidity is lower, and therefore the flow conductance κ decreases. For example, κ = a
R / η + b is defined as a function such that κ increases with increasing R and κ decreases with increasing η. In this case, a is a positive proportional coefficient and b is R = 0, that is, a coefficient indicating the flow conductance on the surface of the mold. These constants
a and b are determined, for example, by conducting experiments with a typical injection molded product. R / illustrated here
The linear expression regarding η has a characteristic that the calculation time is completed in a short time as the simplest mode in which the function F 1 is specified. Also,
Depending on the type of injection-molded product, another form of calculation formula in which the analysis result and the actual molding result are in good agreement may be used.

The material viscosity η changes according to the temperature and the shear rate, and can be expressed by an approximate expression as shown in the equation (6). Here, A, B, and C are coefficients peculiar to the material and can be experimentally obtained by a viscosity measuring device. Equation (6)
By substituting the approximate value of the material viscosity by Eq. (5) into the equation (5), it is possible to easily incorporate the effect of the change in material viscosity due to the change in shear rate and temperature into the flow conductance calculation.

[0071]

(Equation 8) Further, the flow conductance κ may be obtained as follows.

That is, the present inventor found a method of obtaining the flow conductance κ by solving the differential equation shown in the equation (7). Here, x, y, and z are three-dimensional spatial coordinate axes, and η is the material viscosity.

[0073]

(Equation 9) The present inventor has found that this equation (7) is an equation expressing the balance of forces in the flow field where the viscous force is dominant,
Substituting the first equation of, the flow velocity U is eliminated, and the pressure P
It was found that it can be obtained by omitting the second derivative terms with respect to x, y, and z of. By omitting this second-order differential term, κ can be obtained by the simple method described below.

[0074]

(Equation 10) Equation (7) is isomorphic to the general equation for heat conduction. In the heat conduction problem, the temperature T
Alternatively, if a temperature gradient is set in advance as a boundary condition, the temperature distribution inside the region can be calculated by the finite element method, boundary element method, difference method,
It is known that it can be obtained by a numerical analysis method such as the control volume method. Therefore, by setting a boundary condition that makes κ zero on the surface of the mold, which is the boundary of the region, and solving equation (7), the distribution of κ that is smaller as it is closer to the mold surface and larger as it is farther is set for heat conduction problems. It can be obtained using an analysis method or analysis program. Note that the boundary condition of κ = 0 is that the velocity on the mold surface is 0, as is clear from Equation (1).
Is equivalent to assuming that When considering the slippage of the material on the surface of the mold, κ = 0.01 mm 2 / (Pa ・ se
It can be realized by substituting a small non-zero value such as c).

Further, the approximate value of the material viscosity obtained by the equation (6) is given by
By substituting in (7), the effect of changes in material viscosity due to changes in shear rate and temperature can be easily incorporated into the flow conductance calculation.

According to this method, as compared with the method of determining the flow conductance κ using the above equation (5), the heat conduction equation needs to be solved, but the calculation time is longer, but the accuracy is higher for any shape. It becomes possible to obtain good flow conductance. As mentioned above, since equation (7) is derived based on equation (8), which is an equation expressing the balance of forces in the flow field where the viscous force is dominant, we use equation (5). The physical validity of the obtained value is higher than that of the method.
Therefore, it is possible to always give accurate analysis results without being influenced by the shape of the injection-molded product or the model of division into minute elements.

For example, when a minute element having a cross sectional shape as shown in FIGS. 3 and 4 is used, according to the method of determining the flow conductance using the equation (5), it is regularly divided as shown in FIG. The flow conductance can be determined accurately and at high speed with the minute element shape. However, in the irregular minute element shape as shown in FIG. 4, the adjacent element centroid positions are not constant with respect to the surface of the mold, so that the obtained flow conductance is also obtained. It may be inaccurate. However, R in equation (5)
As a result, this situation is alleviated by averaging such as using the average value of the distance between the apex closest to the wall surface and the wall surface and the farthest apex.

The method for determining the flow conductance in the thick portion is a particularly effective method when the minute elements in the three-dimensional model have a layered structure of four layers or more or a pure three-dimensional structure. On the other hand, at the site where the microelements included in the part of the constructed three-dimensional model form a layer structure of, for example, three layers or less, it is preferable to use the above-described method of determining the flow conductance in the thin part. Particularly in the case of the one-layer structure as shown in FIG. 12, the method for the thin portion is used.

Generally, minute element division for use in numerical analysis can be automatically carried out by software called a preprocessor, and particularly even in the case of a product having a complicated shape with many protrusions and holes, division can be easily performed. can do. When such automatic division is performed, the microelement shape is generally irregular, but the method that uses Eq. (7) can suppress the effect of the microelement shape to a small size, and it can Even if it is applied to the injection-molded product, it is possible to perform highly accurate analysis. In addition to the above, there are various methods for determining the flow conductance, and a method that realizes high calculation accuracy and calculation speed, especially in the case of a specific shape, can be considered.

Next, a method of manufacturing the injection-molded article by analyzing the injection-molding process by the above-mentioned method, determining the injection-molding conditions based on the result, and deciding the injection-molding condition will be described.

It is possible to obtain the material pressure, the pressure change, or the flow velocity distribution of the injection molding material when an injection molded article is manufactured under the injection molding conditions given as described above. At this time, these results can be utilized for changing / determining the injection molding conditions as follows.

Generally, in injection molding, in order to obtain a molded product with low stress and little distortion, it is desirable that the material pressure is as low as possible, and the pressure gradient is as uniform as possible without an extremely sharp portion or an extremely small gradient portion. Is preferred. Further, regarding the temporal change of the pressure, it is not preferable that the peak pressure is generated due to the rapid pressure increase. By applying such a pressure determination criterion, it is possible to determine the quality of the molding state. Further, it is preferable to apply the criterion based on the flow velocity obtained as described above.

As a method of judging the molding state, it is also possible to judge on the basis of the flow velocity gradient, shear rate and stress, the progress pattern of the filling region and the like. These data can be easily obtained by processing the information of pressure distribution, pressure change or flow velocity distribution obtained by the above-mentioned method. For example, the shear stress can be obtained by setting the velocity gradient between minute elements as the shear rate and multiplying the shear rate by the material viscosity. Further, the progress pattern of the filling region can be analyzed by sequentially determining the portion to be filled next from the speed of the flow front portion.

When a defect is predicted by the above determination method, the molding die design, product design,
By modifying the molding conditions or the materials used, it is possible to manufacture injection-molded articles without defects.

The first modification method is a method of modifying the shape of the mold to change the material flow path and the like. Here, the molding die shape means a material flow path from a material melt injection nozzle to a product shape portion, which is generally called a sprue, runner, or gate. For example, if it is determined that the pressure loss is too large because the flow length from the nozzle to the end of the product is long, the flow length is reduced by branching the runners and flowing them into the product shape part from multiple gates. be able to.

The second modification method is a method of modifying the shape of the injection-molded article and changing the material flow path. For example, when the pressure gradient in the product shape portion is large and a large flow strain is expected to occur, the pressure gradient can be reduced by increasing the product wall thickness.

The third correction method is to change the molding conditions such as the material injection speed, the material temperature or the mold temperature. For example, if it is expected that molding will be difficult due to a sharp rise in pressure at the material inlet at a certain time, decrease the material injection speed at this time, or increase the material temperature or mold temperature. The pressure rise can be reduced by.

The fourth modification method is to modify the injection molding material. For example, the material pressure loss is severe,
When molding is expected to be difficult, the pressure loss can be reduced by changing to a low-viscosity, good-flowing material.

The above correction methods may be carried out individually or in combination.
Further, it is preferable that the above correction is automatically performed by using an expert system or the like.

The injection molding conditions are re-examined as described above, and analyzed again by the above-mentioned analysis apparatus of the injection molding process under the condition that a preferable injection molding result is considered to be obtained, until the injection molding condition for obtaining the optimum result is found. Repeat this. When the injection molding conditions that give the optimum result are found, injection molding is carried out under the conditions to manufacture an injection molded product.

The present invention can be applied in principle to all shapes of injection-molded products, but is particularly effective for products in which a three-dimensional shape effect is likely to appear.

A product which is likely to exhibit a three-dimensional shape effect is
Thick-walled molded products whose wall thickness exceeds 5 mm, or 1
Even if the wall thickness is ~ 2mm, the overall product size is 10mm.
A small molded product of a certain size, which is relatively susceptible to the influence of flow in the thickness direction. A three-dimensional analysis is also effective for local flow in a portion where the flow suddenly changes in the thickness direction, such as flow in a stepped portion or a corner portion.

In the present invention, as the molding die, a metal mold processed by a precise machining means such as electric discharge machining is used.

The analysis apparatus and the analysis method of the fluid flow process of the present invention can be preferably used not only for the injection molding process but also for analysis of general fluid flow processes. For example,
In particular, it is suitable for analysis of a flow process involving three-dimensional material flow such as material flow in an extrusion molding die, flow in an extruder screw groove, and flow in a kneader.

That is, it can be applied to obtain the pressure distribution during extrusion flow, the distribution of pressure change, or the flow velocity distribution of material in the flow in the die during extrusion molding of a round bar or flat plate, or profile extrusion molding. Pressure gradient and flow velocity
In a portion close to 0, the quality of the molded product is deteriorated due to retention of material and thermal deterioration, so it is necessary to determine the extrusion molding conditions such as the die shape so as to prevent the retention portion from occurring. The present invention is also suitable for such applications.

Similarly, the screw portion of an injection molding machine or an extrusion molding machine can be applied to determine conditions such as a screw design having a small amount of staying portion. It is also possible to calculate the shear stress distribution in the screw groove in an extruder-type kneader and use it for the design for maximizing the shear stress value.

[0097]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a detailed description with reference to the drawings of an embodiment of a fluid flow process analyzing apparatus and method according to the present invention, which is an injection molding process analyzing apparatus, analysis method and injection molded article manufacturing method. Explained.

[Embodiment 1] Here, as shown in FIG.
An example for a plastic case will be described.

First, in step 1 of FIG. 2, injection molding conditions (material used: ABS resin, injection temperature: 250 ° C., mold temperature: 50 ° C., filling time: 2 sec) were input. Subsequently, in step 2, the shape of the injection molded product was divided into a plurality of three-dimensional microelements 14 as shown in FIG. 6 to construct a three-dimensional model of the injection molded product. In this embodiment, three-dimensional microelements are automatically created by the automatic element division function of the finite element method preprocessor based on the three-dimensional CAD data used for designing a molded product. The time required for element division using an engineering workstation was about 3 minutes.
Similar results are obtained using CAD surface data, as described above.

Subsequently, in step 3 of FIG. 2, the wall thickness H of the thin wall portion was calculated. The wall thickness H was automatically calculated from the volume V of the three-dimensional element and the area S of the surface in contact with the cavity by the formula H = 3V / S. Since the molded product of this example has a thin structure as a whole, the thickness of all microelements can be measured by this method.
H (2 to 3 mm) was obtained, and in step 4, this H was used to obtain the flow conductance κ by the equation (4). It should be noted that the calculation of the wall thickness can be obtained from the CAD data or the surface data of CAD by the same calculation value depending on the distance that the normal line of the surface element passes through the model.

Then, in step 5 of FIG. 2, the material pressure distribution during injection molding in each minute element was obtained by solving the equation (3) based on the flow conductance κ by a numerical calculation program similar to the heat conduction analysis. . Actually, the flow conductance in step 4 is determined again based on the result of step 5, and the value at the next moment is obtained repeatedly. Graphically process this result in step 6,
The pressure distribution as shown in FIG. 7 was obtained. Here, the pressure of each microelement is displayed in contour lines. A series of calculations starting from step 2 was completed in about 40 minutes using an engineering workstation.

Further, based on the obtained pressure distribution, a pressure change distribution (FIG. 8) and a flow velocity distribution (FIG. 9) were obtained. Furthermore, the shear stress distribution was also calculated. According to the obtained results of these analyses, the maximum pressure change is 30 MPa and the flow velocity is 30 MPa.
This injection-molded product was manufactured because it was judged that there was no particular problem in injection molding because the shear stress was ~ 200 mm / sec and the shear stress was 10,000 Pa or less. The manufactured injection-molded product was manufactured under optimum conditions, and thus had excellent properties such as strength.

If a defective molding is expected here, for example, an extreme pressure gradient portion is generated, the shape of the molded product, molding conditions, materials, etc. are changed and repeated from step 1 to obtain a proper product. Obtain design, mold design, molding conditions, etc.

[Comparative Example 1] With respect to the same injection-molded article as in Example 1, the same analysis as in Example was carried out except that a two-dimensional model as shown in FIG. 10 was constructed. In this model construction, the neutral plane in the thickness direction of each part having a three-dimensional shape is redefined, the redefined neutral plane is divided into two-dimensional microelements, and the thickness is divided into the divided microelements. Created by setting.
The two-dimensional minute elements were created automatically by automatic element division, but the operator needed to manually input the neutral plane definition, so it took 3 hours to model.

Example 2 Next, a flow analysis of a plastic molded product having both a thin portion and a thick portion as shown in FIG. 11 was conducted, and an injection molded product was manufactured based on the result. As shown in FIG. 12, the model construction was performed by dividing the entire thin-walled portion into three-dimensional minute elements. The injection molding conditions were such that the material used was nylon resin, the injection temperature was 280 ° C., the mold temperature was 80 ° C., and the filling time was 1 second.

In step 2 of FIG. 2, the engineering workstation automatically divided the elements. The time required for this was about 1 minute. The following series of analysis time was about 10 minutes.

The flow conductance was obtained by using the equation (7) in the thick portion, and by the equation (4) in the thin portion where the minute element constitutes a layer structure of one layer. The obtained pressure distribution (maximum pressure 10 MPa) is shown in FIG. 13, the pressure change distribution (maximum pressure change 20 MPa / sec) is shown in FIG. 14, and the material flow velocity distribution (20-50 mm / sec) is shown in FIG. .
Shear stress was less than 5000Pa. In all cases, the results are reasonable as showing the flow of material in the molded article of this shape.

As a result, it was judged that there was no problem in carrying out the injection molding, so that a molded product was manufactured and a good molded product was obtained.

[Comparative Example 2] Regarding the same injection-molded article as in Example 2, as shown in FIG.
Analysis was performed by the same method as in Example 2 except that a model was constructed in which the thin portion was divided by the two-dimensional minute elements for the thin portion by the dimensional minute elements.

As in the case of Comparative Example 1, it took time to model the thin portion because the neutral plane in the thickness direction was defined.

Further, in the connecting portion of the two-dimensional model portion and the three-dimensional model portion, a situation different from the actual material flow is modeled, and thus the obtained pressure distribution and the like are different from those in the second embodiment. It was different. That is, the result was obtained that an abnormally high pressure was generated in the connection portion. Based on this result, it may be determined that there is a problem as the injection molding condition.

[0112]

According to the analyzing apparatus and the analyzing method of the fluid flow process of the present invention, the flow conductance κ is obtained based on the flow thickness in the narrow portion of the cavity, and thus the pressure distribution is obtained. In 3
It is possible to faithfully reproduce the shape of the cavity using a dimensional model, and to perform accurate analysis within a practical calculation time.

Further, according to the analyzing apparatus and the analyzing method of the fluid flow process of the present invention, the flow conductance κ is obtained based on the flow thickness in the narrow portion of the cavity, while the equation (5) or the expression is obtained in the wide portion. Since the flow conductance κ is determined using equations that have established a fast and precise solution method such as (7), the flow conductance κ can be easily obtained and accurate analysis results can be obtained in a practical calculation time. it can.

According to the apparatus and method for analyzing the injection molding process of the present invention, the flow conductance κ is obtained based on the wall thickness in the thin portion, and the pressure distribution and the like are thus obtained. In the analysis,
It is possible to faithfully reproduce the shape of the molded product using a three-dimensional model and to perform accurate analysis within a practical calculation time.

Further, according to the analyzing apparatus and the analyzing method of the injection molding process of the present invention, the flow conductance κ is obtained based on the wall thickness in the thin portion, while the expression (5) and the expression (7) are obtained in the thick portion. Since the flow conductance κ is determined using an equation or the like that has established a fast and precise solution method, it is possible to easily obtain the flow conductance κ and obtain an accurate analysis result in a practical calculation time.

Further, according to the method for manufacturing an injection-molded article of the present invention, the above-mentioned analysis apparatus for the injection-molding process is used,
By determining injection molding conditions such as product shape, mold design, and material selection, high quality injection molded products can be efficiently manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a hardware configuration example of a fluid flow process (injection molding process) analysis device of the present invention.

FIG. 2 is a flow chart showing an example of a procedure of an injection molding process analysis method and an injection molded article manufacturing method of the present invention.

FIG. 3 is a conceptual diagram showing an example of a method for determining a flow conductance used in the present invention.

FIG. 4 is a conceptual diagram showing an example of a method for determining flow conductance used in the present invention.

FIG. 5 is a diagram showing an injection-molded product to be analyzed in an example of the present invention.

FIG. 6 is a diagram showing how a target minute element is determined in an embodiment of the present invention.

FIG. 7 is a diagram showing a calculation result of a material pressure distribution state of an injection-molded article in one example of the present invention.

FIG. 8 is a diagram showing a calculation result of a distribution state of changes in material pressure of an injection-molded product in one example of the present invention.

FIG. 9 is a diagram showing a calculation result of a flow velocity distribution state of a material of an injection-molded article in one example of the present invention.

10 is a diagram showing a case where the injection-molded article of FIG. 5 is modeled by a conventional method.

FIG. 11 is a diagram showing an injection-molded product to be analyzed in one example of the present invention.

FIG. 12 is a diagram showing how a target minute element is determined in an embodiment of the present invention.

FIG. 13 is a diagram showing a calculation result of a material pressure distribution state of an injection-molded article in one example of the present invention.

FIG. 14 is a diagram showing a calculation result of a distribution state of changes in material pressure of an injection-molded article in one example of the present invention.

FIG. 15 is a diagram showing a calculation result of a flow velocity distribution state of a material of an injection-molded article in one example of the present invention.

16 is a diagram showing a state where a model is constructed by disassembling the thin-walled portion into two-dimensional minute elements and the thick-walled portion into three-dimensional minute elements of the injection-molded article of FIG.

FIG. 17 is a diagram illustrating a state in which a model is constructed by decomposing a narrow portion into a two-dimensional minute element in a narrow portion and a three-dimensional minute element in a wide portion.

FIG. 18 is a diagram illustrating a fluid flow state obtained when a model is constructed by decomposing a cavity including a narrow portion into three-dimensional minute elements.

FIG. 19 is a diagram illustrating a fluid flow obtained when a model is constructed by disassembling a narrow portion of a cavity into two-dimensional minute elements and a wide portion into three-dimensional minute elements. is there.

[Explanation of symbols]

 3: Center of gravity of minute element 4: Shortest distance from center of gravity of minute element to mold surface 5: Contact area between minute element divided product and mold surface 6: Section of minute element 7: Minute element 8: Center of gravity of minute element 9: Minute Shortest distance from the element center of gravity to the surface of the molding die 10: Microelements The contact part between the product and the surface of the molding die 11: Microelement cross section 12: Microelements 13: Microelements 14: Microelements 15: Pressure contour lines 16: Microelements 17: Thick part 18: Thin part 19: Three-dimensional minute element 20: Two-dimensional minute element 21: Connection part 22: Three-dimensional minute element 23: Three-dimensional minute element 24: Cross section of three-dimensional minute element 25: Cross-section of two-dimensional micro element 26: Connection part 27: Upper surface of actual thin portion of molded product 28: Lower surface of actual thin portion of molded product 101: Computer 102: Auxiliary storage device 103: Input device 104: Display device 201: Thin part of molded product 202: Thick part of molded product 203: Flow velocity vector 204: Two-dimensional minute element 205: Three-dimensional minute element 206: Flow velocity vector

Claims (19)

[Claims] 1. A three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of a cavity in which a fluid flows is divided into a large number of minute elements, and a fluid of each of the minute elements belonging to a narrow portion of the cavity. The flow conductance κ is determined based on the thickness of the narrow portion, and on the other hand, in each of the minute elements belonging to the wide portion of the cavity, a small value is set when the minute element is close to the cavity wall surface. Of the fluid in each of the microelements based on the flow conductance κ, and the flow conductance κ for determining the flow conductance κ of the fluid such that the flow conductance κ of the fluid is large at a distant position. An apparatus for analyzing a fluid flow process, comprising: a pressure calculating unit for obtaining the pressure. 2. A three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of a cavity in which a fluid flows is divided into a large number of minute elements, and a fluid in each of the minute elements belonging to a narrow portion of the cavity. The flow conductance κ is determined based on the thickness of the narrow portion, and on the other hand, in each of the minute elements belonging to the wide portion of the cavity, a small value is set when the minute element is close to the cavity wall surface. Flow conductance κ of the fluid and a flow conductance determination means for determining the flow conductance κ of the fluid such that the fluid conductance κ of the fluid is large when located at a distant position, and a pressure change of the fluid in each of the microelements based on the flow conductance κ. An apparatus for analyzing a fluid flow process, which comprises: 3. A three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of a cavity in which a fluid flows is divided into a large number of microelements, and a fluid in each of the microelements belonging to a narrow portion of the cavity. The flow conductance κ is determined based on the thickness of the narrow portion, and on the other hand, in each of the minute elements belonging to the wide portion of the cavity, a small value is set when the minute element is close to the cavity wall surface. Flow conductance κ of the fluid and a flow conductance determination means for determining the flow conductance κ of the fluid such that the flow conductance κ of the fluid is large when the fluid is located at a distant position, and the flow velocity of the fluid in each of the microelements based on the flow conductance κ. An apparatus for analyzing a fluid flow process, which comprises: 4. A three-dimensional model in which at least a part of a fluid flowing cavity is divided into a large number of minute elements,
The flow conductance κ of the fluid in each of the microelements is determined based on the flow thickness of the cavity in each of the microelements, and the pressure of the fluid in each of the microelements is obtained based on the obtained flow conductance κ. A method of analyzing a fluid flow process, characterized in that the fluid flow process is analyzed by the applied pressure. 5. A three-dimensional model in which at least a part of a fluid flowing cavity is divided into a large number of minute elements,
The flow conductance κ of the fluid in each of the microelements is determined based on the flow thickness of the cavity in each of the microelements, and the pressure change of the fluid in each of the microelements is obtained based on the obtained flow conductance κ,
A method for analyzing a fluid flow process, characterized by analyzing the fluid flow process based on the obtained pressure change. 6. A three-dimensional model in which at least a part of a fluid flowing cavity is divided into a large number of minute elements,
The flow conductance κ in each micro element of the fluid is determined based on the flow thickness of the cavity in each micro element, and the flow velocity of the fluid in each micro element is determined based on the obtained flow conductance κ,
A method for analyzing a fluid flow process, characterized by analyzing the fluid flow process based on the obtained flow velocity. 7. A three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of an injection-molded product is divided into a large number of microelements, and an injection-molding material in each of the microelements belonging to a thin portion of the injection-molded product. Is determined based on the thickness of the thin-walled portion, and on the other hand, in each of the micro-elements belonging to the thick-walled portion of the injection-molded product, a small value is set when the micro-elements are close to the mold surface. The flow conductance κ of the injection molding material is determined so that the flow conductance κ of the injection molding material is determined to be a large value at a distant position, and the above-mentioned flow conductance κ based on the flow conductance κ. An analysis device for an injection molding process, comprising: a pressure calculation means for calculating a pressure of the injection molding material in a minute element. 8. A three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of an injection-molded product is divided into a large number of microelements, and an injection-molding material in each of the microelements belonging to a thin portion of the injection-molded product. Is determined based on the thickness of the thin-walled portion, and on the other hand, in each of the micro-elements belonging to the thick-walled portion of the injection-molded product, a small value is set when the micro-elements are close to the mold surface. The flow conductance κ of the injection molding material is determined so that the flow conductance κ of the injection molding material is determined to be a large value at a distant position, and the above-mentioned flow conductance κ based on the flow conductance κ. An analysis device for an injection molding process, comprising: a pressure change calculation means for obtaining a pressure change of the injection molding material in a minute element. . 9. A three-dimensional model constructing means for constructing a three-dimensional model in which at least a part of an injection-molded product is divided into a large number of microelements, and an injection-molding material in each of the microelements belonging to the thin-walled part of the injection-molded product. Is determined based on the thickness of the thin-walled portion, and on the other hand, in each of the micro-elements belonging to the thick-walled portion of the injection-molded product, a small value is set when the micro-elements are close to the mold surface. The flow conductance κ of the injection molding material is determined so that the flow conductance κ of the injection molding material is determined to be a large value at a distant position, and the above-mentioned flow conductance κ based on the flow conductance κ. And a flow velocity calculating means for calculating the flow velocity of the injection molding material in the minute element. . 10. The analysis of the injection molding process according to claim 7, wherein the three-dimensional model construction means constructs a three-dimensional model based on CAD data or CAD surface data of an injection molded product. apparatus. 11. A three-dimensional model in which at least a part of an injection-molded product is divided into a large number of microelements is constructed, and a flow conductance κ of an injection-molding material in each of the microelements is calculated from the injection conductance of the injection-molded product in each of the microelements. Determining the pressure of the injection molding material in each of the microelements based on the obtained flow conductance κ, and analyzing the injection molding process of the injection molded product by the obtained pressure. A method for analyzing an injection molding process characterized by: 12. A three-dimensional model in which at least a part of an injection-molded product is divided into a large number of minute elements is constructed, and a flow conductance κ of an injection-molding material in each of the minute elements is calculated as a flow conductance κ of the injection-molded product in each of the minute elements. The pressure change of the injection molding material in each of the minute elements is determined based on the obtained flow conductance κ, and the injection molding process of the injection molded article is analyzed based on the obtained pressure change. A method for analyzing an injection molding process, which comprises: 13. A three-dimensional model in which at least a part of an injection-molded article is divided into a large number of microelements is constructed, and a flow conductance κ of each of the microelements of the injection molding material is calculated as a flow conductance κ of each of the microelements. The flow velocity of the injection molding material in each of the minute elements is determined based on the obtained flow conductance κ, and the injection molding process of the injection molded article is analyzed based on the obtained flow velocity. A method for analyzing an injection molding process, which comprises: 14. A three-dimensional model in which at least a part of an injection-molded product is divided into a large number of microelements is constructed, and the flow conductance κ of the injection-molding material is calculated in each of the microelements belonging to the thin-walled part of the injection-molded product. Determined based on the thickness of the thin portion, on the other hand, the flow conductance κ in each of the microelements belonging to the thick portion of the injection-molded product is increased by increasing the shortest distance R between the microelement and the mold surface. The injection molding material in each of the microelements is determined by a function F (R, η) that increases and decreases with an increase in the material viscosity η of the injection molding material, and based on the obtained flow conductance κ. The method for analyzing an injection molding process is characterized in that the injection molding process of the injection-molded article is analyzed based on the obtained pressure. 15. A three-dimensional model in which at least a part of an injection-molded product is divided into a large number of microelements is constructed, and the flow conductance κ of the injection-molded material is calculated in each of the microelements belonging to the thin-walled part of the injection-molded product. The flow conductance κ is determined based on the thickness of the thin portion, while the flow conductance κ in each of the minute elements belonging to the thick portion of the injection-molded product is expressed by (Η represents the material viscosity of the injection molding material, x, y and z represent the positions of the microelements), and
The pressure of the injection molding material in each of the minute elements is obtained based on the obtained flow conductance κ, and the injection molding process of the injection molded article is analyzed by the obtained pressure. analysis method. 16. An injection molding condition for an injection molded product is defined, and a three-dimensional model in which at least a part of the injection molded product is divided into a large number of minute elements is constructed, and each of the minute particles belonging to the thin-walled portion of the injection molded product is constructed. In the element, the flow conductance κ of the injection-molding material is determined based on the thickness of the thin-walled portion, while, in each of the micro-elements belonging to the thick-walled portion of the injection-molded product, the micro-element is at a position close to the mold surface. If the flow conductance κ of the injection molding material is determined to be a small value, the flow conductance κ of the injection molding material is determined to be a large value at a distant position, and based on the obtained flow conductance κ The pressure of the injection molding material in each of the microelements is obtained, the injection molding conditions are finally determined based on the obtained distribution of the pressure, and the finally determined injection composition is obtained. Method for manufacturing an injection-molded article, characterized in that the production of injection-molded article based on a condition. 17. A three-dimensional model in which injection molding conditions for an injection molded product are defined, and at least a part of the injection molded product is divided into a large number of minute elements, and each of the minute particles belonging to the thin-walled portion of the injection molded product is constructed. In the element, the flow conductance κ of the injection-molding material is determined based on the thickness of the thin-walled portion, while, in each of the micro-elements belonging to the thick-walled portion of the injection-molded product, the micro-element is at a position close to the mold surface. If the flow conductance κ of the injection molding material is determined to be a small value, the flow conductance κ of the injection molding material is determined to be a large value at a distant position, and based on the obtained flow conductance κ Then, the pressure change of the injection molding material in each of the minute elements is obtained, the injection molding conditions are finally determined based on the obtained distribution of the pressure change, and the final determination is made. Method for manufacturing an injection-molded article, characterized in that the production of injection-molded article based on the injection molding conditions. 18. A three-dimensional model in which injection molding conditions for an injection-molded product are determined, and at least a part of the injection-molded product is divided into a large number of microelements, and each of the minute parts belonging to the thin-walled part of the injection-molded product is constructed. In the element, the flow conductance κ of the injection-molding material is determined based on the thickness of the thin-walled portion, while, in each of the micro-elements belonging to the thick-walled portion of the injection-molded product, the micro-element is at a position close to the mold surface. If the flow conductance κ of the injection molding material is determined to be a small value, the flow conductance κ of the injection molding material is determined to be a large value at a distant position, and based on the obtained flow conductance κ Then, the flow velocity distribution of the injection molding material in each of the minute elements is obtained, the injection molding conditions are finally determined based on the obtained flow velocity distribution, and the final determination is made. Method for manufacturing an injection-molded article, characterized in that the production of injection-molded article based on the injection-molding conditions. 19. The injection molding condition includes any one of a shape of the injection molded product, a molding die shape, a material injection speed, a material temperature, a molding die temperature, and an injection molding material. Item 19. A method for manufacturing an injection-molded article according to any one of Items 16-18.