JP2008001088A - Prediction method, apparatus, its program, storage medium for secondary weld line, manufacturing method of moldings by using them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an analyzing method and an apparatus to examine a secondary weld line easily and quickly by exactly securing a generation phenomenon of the secondary weld line generated in a series of steps comprising applying an arbitrary pressure for suppressing a contraction of a product by cooling, during filling a molten material into a mold and after completion of the filling, correctly securing the secondary weld line generated, and also to provide a storage medium for storing a computer program for providing such an analyzing method. <P>SOLUTION: The method for predicting the secondary weld line comprises: executing a flow analysis, based on an analytical geometric model for a flow analysis; acquiring a fluid vector and a primary weld line from the result of the flow analysis; making the secondary weld line virtual particles generate by making the primary weld line serve as the starting point: and carrying out to analyzing to secure a secondary weld line prediction to make a figure of the secondary weld line prediction virtual particle distribution, which shows that the secondary weld line prediction virtual particles move by flow vector, serve as the secondary weld line. However, the position where the secondary weld line prediction virtual particles generate is moved according to the flow vector. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the molding process of a molded product such as an injection molded product, a die-cast product, a thixo molding product, and a cast product, the present invention provides a portion where a plurality of melt molding materials flow in the molding die and a thickness difference in the molded product die. The present invention relates to a method and an apparatus for predicting the position of a secondary weld line formed by moving a weld line (referred to as a primary weld line) generated at a site where a flow rate is significantly changed by a subsequent flow of molten material.

  One of the molding defects in injection molding is the weld line. This weld line causes various problems by appearing as defects in appearance and strength in plastic products. As a pattern for generating a weld line, (1) When different flow fronts merge at a multi-point gate, etc., (2) When flowing around a hole such as a fault pin, the flow front once branches and merges again. In this case, (3) a case where a large difference appears in the way the flow front proceeds at a step portion having a difference in thickness.

  In particular, in a resin containing a filler, a weld line (secondary weld line) that is newly formed by once a generated weld line (referred to as a primary weld line) is moved by a subsequent resin flow. Are often problematic. While this secondary weld line is problematic in appearance because it produces shades and irregularities in the product, the area of the weld interface is reduced because one of the fluid resins sinks into the other fluid resin. Spreading is known to improve mechanical strength. Conventionally, as a method for predicting such a secondary weld line, in Patent Document 1, a plurality of virtual particles are generated on a weld line generated when fluid resins come into contact with each other, and a moving path of the virtual particles is obtained. By calculating the moving distance, the position of the secondary weld line is obtained by obtaining the submerged distance that one of the fluid resins penetrates into the other fluid resin.

  Further, in Patent Document 2, the resin flow rate distribution after forming the weld is obtained by injection flow analysis software, and the deformation dimension of the weld surface is calculated from the product of the obtained resin flow rate and the time until completion of filling after forming the weld line. The position of the secondary weld line is obtained by calculation.

Patent Publication 2000-343575 Patent Publication No. 7-68616

  In Patent Document 1, virtual particles are generated on a primary weld line generated when fluid resins come into contact with each other, and the movement path of the virtual particles is calculated by calculating the movement distance of one of the fluid resins. In order to determine the submerged distance that has entered the resin, on the primary weld line on which the virtual particles generated when the direction of the subsequent flow resin flow after the generation of the virtual particles is parallel to the primary weld line are already formed. Even in the case of tracing, it is obtained as a submerged distance that one of the fluid resins penetrates into the other fluid resin. That is, there is a problem that even if one of the fluid resins does not sink into the other fluid resin, it is recognized that one of the fluid resins penetrates into the other fluid resin.

  In Patent Document 2, similarly to Patent Document 1, it is not assumed that the molten material flow is parallel to the primary weld line after the primary weld line is formed.

  Therefore, the present invention provides a method for accurately predicting the position of the secondary weld line that moves according to the flow vector that changes through the filling process after the primary weld line is generated.

The present invention has the following configuration in order to solve the above problems.
That is, when the secondary weld line position is predicted by performing flow analysis on the behavior of the molten material in the mold during the molding process of the molded product, Analytical condition reading step for reading physical property data and molding condition data into memory, flow analysis step for performing flow analysis based on analysis shape model, material property data, and molding condition data, and data in memory of flow analysis step A flow vector creation step for obtaining a flow vector at each element or node in the analysis shape model based on the above, and a primary weld line position determination step for obtaining a position that becomes a primary weld line at a flow tip portion at a certain time from the start of flow analysis; The primary weld line position is set to the initial secondary weld line virtual particle generation. An initial secondary weld line virtual particle generation position determining step determined as a position and the secondary weld line virtual particle at any time step after the flow front passes through the initial secondary weld line virtual particle generation position until the flow analysis ends. A secondary weld line virtual particle generating step, a secondary weld line virtual particle tracking step of moving the secondary weld line virtual particle by the flow vector, and the secondary weld line virtual particle is the initial secondary weld. A secondary weld line that moves the secondary weld line virtual particle generation position closest to the position of the secondary weld line virtual particle to the position of the secondary weld line virtual particle when moved to a position different from the line virtual particle generation position. Virtual particle generation position moving step and secondary weld line virtual particle A secondary weld line virtual particle generation position re-determining step for re-determining the secondary weld line virtual particle generation position moved by the generation position moving step as a secondary weld line virtual particle generation position; There is provided a secondary weld line prediction method characterized in that the distribution form of secondary weld line virtual particle generation positions is a secondary weld line.

[Action / Effect]
In the conventional analysis method, a prediction of only the primary weld line formed by the locus of the point where a plurality of molten materials meet, or a simulation for predicting the movement of the primary weld line by controlling the molding conditions of a plurality of gates, etc. In the method of the present invention, the flow analysis is performed based on the analysis shape model, the material property data, and the molding condition data, and the flow vector at each element or node in the analysis shape model is calculated based on the data on the memory. In parallel, the primary weld line is obtained by connecting the molten resin confluence prediction points at the flow front end portion at a certain time from the start of the analysis. Each time the flow front reaches the predicted position of the conventional primary weld line, the initial secondary weld line virtual particle generation position is continuously defined, and the secondary weld line virtual particle generation position is further defined at each secondary weld line virtual particle generation position. Weld line virtual particles are generated and moved by the flow vector of the molten material. When the secondary weld line virtual particles moved and tracked disappear at the primary weld line or the secondary weld line virtual particle generation position, and the secondary weld line virtual particles move to other positions, the secondary weld line virtual particles The secondary weld line virtual particle generation point closest to the particle is moved to the position of the secondary weld line virtual particle. Thus, the secondary weld line virtual particle generation position moving step and the secondary weld line virtual particle generation position re-determining step are repeated until the molten material filling is completed, and the secondary weld line virtual particle generation points that have moved are continuously connected. By defining the approximate curve as the secondary weld line, it is possible to predict and analyze the weld line generation position to be confirmed in the actual molded product.

  Further, in the second aspect of the invention, the secondary weld line virtual particle generation position moving step of the above-mentioned two-weld line prediction method is such that the flow vector at the secondary weld line virtual particle generation position is the primary weld line generation direction or A secondary weld line prediction method is provided, wherein the secondary weld line virtual particle generation position is moved by the flow vector when the secondary weld line virtual particle generation position is changed.

[Action / Effect]
Instead of generating and moving the secondary weld line virtual particles, the primary weld line generation direction and the secondary weld line virtual particle generation position are stored at the secondary weld line virtual particle generation position, and the flow vector is different from these directions. When the secondary weld line virtual particle generation position is moved by the flow vector when the direction changes, the flow vector at the position where the primary weld line is formed is different from the generation direction of the primary weld line after a certain time. It becomes possible to predict the secondary weld line that is formed when it is changed to.

  According to a third aspect of the present invention, the flow vector creation step of the two-weld line prediction method obtains a flow vector at each element or node in the analysis shape model based on an output result of the flow analysis step. A secondary weld line prediction method is provided.

[Action / Effect]
When the present invention is implemented in the filling analysis, the memory used increases, so the secondary weld line position is calculated while reducing the memory used by calculating the secondary weld line position based on the result of the filling analysis. It is characterized by seeking.

  Further, the invention according to claim 4 provides a secondary weld line prediction method characterized in that the distribution form of secondary weld line virtual particles at the end of the analysis is a secondary weld line.

[Action / Effect]
By using the information of the secondary weld line virtual particle position, which has a larger amount of information than the secondary weld line virtual particle generation position, it becomes possible to predict the position of the next weld line in more detail.

  Further, the invention according to claim 5 predicts the secondary weld line position by performing flow analysis on the behavior of the molten material in the mold during the molding process of the molded product. Analytical condition reading means for reading data and molding condition data into a memory, flow analysis means for performing flow analysis based on the analytical shape model, the material property data, and the molding condition data, and data on the memory of the flow analysis means A flow vector creating means for obtaining a flow vector at each element or node in the analysis shape model, a primary weld line position determining means for obtaining a position that becomes a primary weld line at a flow front portion at a certain time from the start of flow analysis; The primary weld line position is the initial secondary weld line virtual particle generation position. Secondary weld line virtual particle generation position determining means and the initial secondary weld line virtual particle generation position to be determined at any time step after the flow front passes through the initial secondary weld line virtual particle generation position to the end of the flow analysis. Secondary weld line virtual particle generating means, secondary weld line virtual particle tracking means for moving the secondary weld line virtual particle by the flow vector, and the secondary weld line virtual particle is the initial secondary weld. A secondary weld line that moves the secondary weld line virtual particle generation position closest to the position of the secondary weld line virtual particle to the position of the secondary weld line virtual particle when moved to a position different from the line virtual particle generation position. Virtual particle generation position moving means and secondary weld line virtual particle generation Secondary weld line virtual particle generation position redetermining means for re-determining the secondary weld line virtual particle generation position moved by the placement moving means as the secondary weld line virtual particle generation position; There is provided a secondary weld line prediction apparatus characterized in that the distribution form of the next weld line virtual particle generation position is a secondary weld line.

  According to the sixth aspect of the present invention, the secondary weld line virtual particle generation position moving means of the two-weld line prediction apparatus is configured such that the flow vector at the secondary weld line virtual particle generation position is the primary weld line generation direction or 2 There is provided a secondary weld line prediction apparatus characterized by moving a secondary weld line virtual particle generation position by the flow vector at a time point when the generation position changes from the generation position of the next weld line virtual particle.

  The invention according to claim 7 is characterized in that the flow vector creation means of the two-weld line prediction method obtains a flow vector at each element or node in the analysis shape model based on the output result of the flow analysis means. A secondary weld line prediction apparatus is provided.

  The invention according to claim 8 provides a secondary weld line prediction device characterized in that the distribution form of secondary weld line virtual particles at the end of analysis is a secondary weld line.

  The invention according to claim 9 provides a computer program for executing each step of the secondary weld line prediction method using a computer.

  The invention according to claim 10 provides a computer-readable storage medium storing the computer program.

  The invention according to claim 11 predicts the secondary weld line position using the above-mentioned secondary weld line prediction method, finally determines the shape, material properties and molding conditions of the molded product. There is provided a method for manufacturing a molded product that efficiently manufactures a molded product in a short period of time through fabrication of a mold, trial shooting, and the like.

  The terms are defined below. In the present invention, an “analysis shape model” refers to data described by nodes, elements, element characteristics, etc. used in a flow analysis using a computer. “Flow vector” refers to a vector that represents the flow direction of the molten material at each element or node. The flow vector may further include the velocity of the flow, and may be held as a set of velocity components in each direction. “Molding conditions” refer to molten material temperature, filling time, filling speed, filling pressure, mold temperature, and the like.

  According to the present invention, an accurate secondary weld line position can be easily predicted based on the result of flow analysis. As a result, the position of the secondary weld line by changing the product thickness or gate position can be examined from the product / mold design stage, and the efficiency of the product / mold design can be improved.

  In this way, by predicting the position of the secondary weld line, the position of the secondary weld line under any manufacturing conditions can be known, so the shape of the molded product, material properties and molding conditions can be determined as necessary. The final manufacturing conditions may be determined by moving the secondary weld line to a preferable position by making appropriate corrections, and a molded product may be actually manufactured based on the result.

  Embodiments of a one-dimensional element generation method and apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an embodiment of an apparatus for performing one-dimensional element generation according to the present invention. In this embodiment, (100) is a computer, (101) is a keyboard, (102) is a mouse, (103) is a display, and (104) is an auxiliary storage device. In addition to the hard disk, removable auxiliary storage devices such as FD (flexible disk), CD (compact disk), MO (magneto-optical disk), PD, DVD (digital multipurpose disk) can be used for (104).

  The auxiliary storage device (104) includes CAD data storage means (105), analysis shape model storage means (106), flow analysis result storage means (107), primary weld line position storage means (108), and secondary weld line. Virtual particle movement locus storage means (109), secondary weld line virtual particle generation position storage means (110) is included.

  The computer (100) includes a CPU and a subroutine developed on a memory, CAD data creation means (111), analysis shape model creation means (112), analysis condition reading means (113), flow analysis means (114), flow Analysis result reading means (115), flow vector creation means (116), primary weld line position determination means (117), initial secondary weld line virtual particle generation position determination means (118), secondary weld line virtual particle generation means (119) Secondary weld line virtual particle tracking means (120), secondary weld line virtual particle generation position moving means (121), and secondary weld line virtual particle generation position re-determination means (122) are included.

  The CAD data creation means (111) is a means for creating the shape of a molded product on a computer, and for example, those installed in many CADs such as CATIA (Dassult) and UniGraphics (UGS) can be used.

  The analysis shape model creation means (112) creates a neutral plane from the CAD data for the CAD data created by the CAD data creation means (111) as shown in FIG. 3, and automatically creates a two-dimensional shell element. Or automatically create 3D solid elements. The method of creating an analytical shape model from CAD data in this way is an existing technology installed in many CADs such as CATIA (Dassult) and UniGraphics (UGS).

  Based on the analysis shape model created by the analysis shape model creation means (112) and the material physical properties read by the analysis condition reading means (113) and the analysis conditions, the flow analysis means (114) It is a means for obtaining temperature and flow velocity, and is an existing technology installed in flow analysis software such as 3D TIMON (Toray) and MOLDFLOW (MOLDFLOW). The shape, material properties, and molding conditions may be read into the memory from the auxiliary storage device (104). However, if the data already developed on the memory is used as it is, the reading is performed with the above expansion. It is considered to have been broken.

  The flow vector creation means (116) obtains the velocity vector of each element (mesh) or each node (mesh intersection point) at an arbitrary analysis step which is one of the results of the flow analysis performed by the flow analysis means (114). Create this and use it as the flow vector. Alternatively, a flow tip arrival time gradient vector may be created based on the flow tip arrival time data, which is one of the results of the flow analysis performed by the flow analysis means (114), and this may be used as the flow vector.

The primary weld line position determining means (117) is a means for determining the position of the primary weld line generated when the flow fronts of the molten material merge, and is obtained by means of, for example, Japanese Patent Publication No. 2002-200622. (See Figs. 6 and 7)
The initial secondary weld line virtual particle generation position determining means (118) is a node closest to the primary weld line position coordinates or the primary weld line position coordinates obtained by the primary weld line position determining means (117). Is stored as the initial secondary weld line generation position.

  The secondary weld line virtual particle generation means (119) has an arbitrary time step from when the flow front passes the generation position determined by the initial secondary weld line virtual particle generation position determination means (118) until the flow analysis is completed. To generate secondary weld line virtual particles.

  The secondary weld line virtual particle tracking means (120) moves the secondary weld line virtual particle along the flow vector created by the flow vector creating means (116), and the position where the virtual particle arrived at each time The coordinates of are stored. Alternatively, the position of the node closest to the coordinates of the position where the virtual particle has reached at each time is stored.

  The secondary weld line virtual particle generation position moving means (121) moves the secondary weld line virtual particle moved by the secondary weld line virtual particle tracking means (120) to a position different from the initial secondary weld line virtual particle generation position. Then, the initial secondary weld line virtual particle generation position closest to the secondary weld line virtual particle is moved to the position of the secondary weld line virtual particle. After the secondary weld line virtual particle generation position moves, the secondary weld line virtual particle is not generated from the past secondary weld line virtual particle generation position.

  The secondary weld line virtual particle generation position re-determination means (122) renews the initial secondary weld line virtual particle generation point moved by the secondary weld line virtual particle generation position movement means (121), and revises the secondary weld line virtual particle generation position. Determine as. The secondary weld line virtual particle generation means (119) newly generates secondary weld line virtual particle from the secondary weld line virtual particle generation position determined here, and the secondary weld line virtual particle tracking means (120). The secondary weld line virtual particle generation position is determined by repeatedly tracking the secondary weld line virtual particle by moving the secondary weld line virtual particle generation position by the secondary weld line virtual particle generation position moving means (121). By moving, the line connecting the distribution centers of the secondary weld line virtual particle generation positions is predicted as the secondary weld line.

  FIG. 4 and subsequent figures show specific secondary weld line prediction examples.

  FIG. 4 is a drawing and CAD data of a flat plate having a dimension of 85 mm × 40 mm, a wall thickness of 1 mm on a general surface, and an uneven wall thickness of 2 mm. FIG. 5 shows an analytical shape model automatically created by a three-dimensional solid element, which is composed of 239956 nodes and 219791 elements.

  About the shape of FIG. 5, the flow pattern which performed the flow analysis using the resin physical property data of polypropylene PP containing talc (Nippon Polypro Co., Ltd. MK3H) and the primary weld line output by the means of Patent Publication 2002-200622 FIG. 6 shows an example of a measured short shot pattern and a measured primary weld using the above resin.

  FIG. 7 shows a secondary weld line and an actual measurement secondary weld line output according to this embodiment. As described above, after the primary weld line is generated, the position of the secondary weld line that moves according to the flow vector that changes through the filling process can be accurately predicted.

  By predicting the position of the secondary weld line in this way, the position of the secondary weld line under any manufacturing conditions can be known, so that the molded product shape, material properties, and molding conditions can be determined as necessary. The final manufacturing conditions may be determined by moving the secondary weld line to a desired position by appropriately correcting the above, and a molded product may be actually manufactured based on the result.

As described above, the secondary weld line prediction apparatus of the present embodiment is realized by a computer and software (program) loaded on the computer. Such software includes hard disk, tangible storage media such as FD (flexible disk), CD (compact disk), MO (magneto-optical disk), PD, DVD (digital multipurpose disk), or transmission means such as a wireless or wired network. It is distributed through.

It is a block diagram which shows the structure of one embodiment of this invention. It is a flowchart of the embodiment of this invention. It is a CAD shape and an analysis shape model figure. 85 × 40 × (1 or 2) Uneven wall thickness flat drawing and CAD data of the flat drawing. 5 is an analytical shape model for the flat plate of FIG. FIG. 6 is a flow pattern, a primary weld line, an actual short shot pattern, and an actual primary weld line for the analysis shape model of FIG. FIG. 7 is a secondary weld line display according to the present invention for the flow pattern of FIG. 6 and the primary weld line.

Explanation of symbols

100 computers
101 keyboard
102 mouse
103 display
104 Auxiliary storage
105 CAD data storage means
106 Analytical shape model storage means
107 Flow analysis result storage means
108 Primary weld line position storage means
109 Secondary Weld Line Virtual Particle Movement Trajectory Storage Means
110 Secondary Weld Line Virtual Particle Generation Position Storage Means
111 CAD data creation means
112 Analytical shape model creation means
113 Method for reading analysis conditions
114 Flow analysis means
115 Flow analysis result reading means
116 Flow vector creation means
117 Primary Weld Line Position Determination Means
118 Initial secondary weld line virtual particle generation position determination means
119 Secondary weld line virtual particle generation means
120 Secondary Weld Line Virtual Particle Tracking Means
121 Secondary Weld Line Virtual Particle Generation Position Moving Means
122 Secondary Weld Line Virtual Particle Generation Position Re-Measuring Unit

Claims (11)

When predicting the secondary weld line position by performing flow analysis of the behavior of the molten material in the mold during the molding process of the molded product, the analysis shape model, material property data and molding condition data of the molded product are read into the memory. Each element in the analysis shape model based on the analysis condition reading step, the analysis shape model, the flow analysis step of performing flow analysis based on the material property data and the molding condition data, and the data on the memory of the flow analysis step A flow vector creation step for obtaining a flow vector at a node, a primary weld line position determination step for obtaining a position that becomes a primary weld line at a flow front portion at a certain time from the start of flow analysis, and the primary weld line position as an initial secondary. Initial secondary well determined as weld line virtual particle generation position A secondary weld line virtual particle generating step for generating a secondary weld line virtual particle at an arbitrary time step after the flow front passes through the initial virtual weld line virtual particle generation position and the initial secondary weld line virtual particle generation position until the flow analysis ends. A particle generation step, a secondary weld line virtual particle tracking step of moving the secondary weld line virtual particles by the flow vector, and a position where the secondary weld line virtual particles are different from the initial secondary weld line virtual particle generation position. A secondary weld line virtual particle generation position moving step of moving the secondary weld line virtual particle generation position closest to the position of the secondary weld line virtual particle to the position of the secondary weld line virtual particle when moving to Moved by the secondary weld line virtual particle generation position movement process A secondary weld line virtual particle generation position re-determining step for re-determining a secondary weld line virtual particle generation position as a secondary weld line virtual particle generation position, and the secondary weld line virtual particle generation position at the end of a predetermined analysis; A secondary weld line prediction method, characterized in that the distribution form is a secondary weld line. The secondary weld line prediction method according to claim 1,
The secondary weld line virtual particle generation position moving step is performed when the flow vector at the secondary weld line virtual particle generation position changes from the primary weld line generation direction or the generation position of the secondary weld line virtual particles. A secondary weld line prediction method, wherein the particle generation position is moved by the flow vector. The secondary weld line prediction method according to claim 1,
A secondary weld line prediction method, wherein a flow vector creation step obtains a flow vector at each element or node in the analysis shape model based on an output result of the flow analysis step. 2. The secondary weld line prediction method according to claim 1, wherein the distribution form of secondary weld line virtual particles at the end of the analysis is a secondary weld line. When predicting the secondary weld line position by performing flow analysis of the behavior of the molten material in the mold during the molding process of the molded product, the analysis shape model, material property data and molding condition data of the molded product are read into the memory. Analysis condition reading means, the analysis shape model, the flow analysis means for performing flow analysis based on the material property data and the molding condition data, and each element in the analysis shape model based on the data on the memory of the flow analysis means A flow vector creating means for obtaining a flow vector at a node, a primary weld line position determining means for obtaining a position of a primary weld line at a flow front end portion at a certain time from the start of flow analysis, and the primary weld line position as an initial secondary. Initial secondary well determined as the weld line virtual particle generation position A secondary weld line virtual for generating secondary weld line virtual particles at any time step after the flow front passes through the initial virtual weld line virtual particle generation position and the initial secondary weld line virtual particle generation position until the end of the flow analysis. Particle generation means, secondary weld line virtual particle tracking means for moving the secondary weld line virtual particles by the flow vector, and a position where the secondary weld line virtual particles are different from the initial secondary weld line virtual particle generation position Secondary weld line virtual particle generation position moving means for moving the secondary weld line virtual particle generation position closest to the position of the secondary weld line virtual particle to the position of the secondary weld line virtual particle when moving to Moved by secondary weld line virtual particle generation position moving means Secondary weld line virtual particle generation position re-determining means for re-determining the next weld line virtual particle generation position as a secondary weld line virtual particle generation position, and the secondary weld line virtual particle generation position at the end of a predetermined analysis A secondary weld line prediction apparatus characterized in that the distribution form is a secondary weld line. The secondary weld line prediction apparatus according to claim 5,
The secondary weld line virtual particle generation position moving means moves the secondary weld line virtual particle generation position by the flow vector when the flow vector of the secondary weld line virtual particle generation position changes. Weld line prediction device. The secondary weld line prediction apparatus according to claim 5,
A secondary weld line prediction apparatus, wherein a flow vector creation means obtains a flow vector at each element or node in the analysis shape model based on an output result of the flow analysis means. 2. The secondary weld line prediction method according to claim 1, wherein the distribution form of the secondary weld line virtual particles at the end of the analysis is a secondary weld line. A computer program for executing each step of the weld line prediction method according to claim 1 using a computer. A computer-readable storage medium storing the computer program according to claim 9. A method for manufacturing a molded product, wherein a weld line position is predicted using the weld line prediction method according to claim 1, the shape, material properties and molding conditions of the molded product are finally determined, and the molded product is manufactured based on the result.

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