JP2008207440A - Quality forecasting apparatus, method, and program of injection-molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To forecast the quality of a molded product by estimating a weld interface shape from the result of the flow analysis of a shell mesh on the molded product in injection molding of resin. <P>SOLUTION: The present invention is embodied as a method estimating the weld interface shape inside of a weld line generated in the injection molding of the resin. The method has a step analyzing the flow of the shell mesh, the step of extracting the position of the weld line from the result of the flow analysis, the step of estimating the time change of the moving quantity along the flowing direction of the resin around the weld line from the result of the flow analysis, the step of estimating the time change the thickness of the flow layer of the resin around the weld line from the result of the flow analysis, and the step of estimating the weld interface shape based on the time change of the moving quantity along the flowing direction of the resin around the weld line and the time change of the thickness of the flow layer of the resin around the weld line. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for predicting quality in resin injection molding. More specifically, the present invention relates to an apparatus, method, and program for estimating a weld interface shape related to a weld line appearing on the surface of a molded product and predicting the quality of the molded product based on the estimated weld interface shape.

  The resin injection molding method is used in various fields because it can accurately produce parts having complicated shapes in one process. In the field of automobile manufacture, for example, many injection molded products such as instrument panels, door inside panels, bumpers, handles, lever handles, various operation buttons, lamp covers, moldings, bonnets, roofs, and small parts are used. Such injection-molded products are required to have high performance such as large size, complicated shape, high accuracy, and high strength.

  One of the problems of the injection molding method is a weld defect. In resin injection molding, a linear mark called a weld line is generated on the surface of a portion where two or more flows of molten material meet at the time of molding. Linear surface distortion may occur in the vicinity of the weld line. When this surface distortion occurs, the appearance of the molded product is impaired depending on the degree of unevenness on the surface, and the commercial value is lowered.

  It is known that the generation mode of surface strain in the vicinity of the weld line changes at the boundary surface between the resin flow and the resin flow in accordance with the distance that one fluid resin sinks into the other fluid resin. Hereinafter, the boundary surface of the resin flow is referred to as a weld interface, and the distance at which one resin sinks into the other resin is referred to as a sinking amount.

  If the behavior of the resin during injection molding can be predicted by flow analysis and the amount of resin penetration at the weld interface can be estimated, it is possible to predict the quality of the molded product in advance without actually conducting a prototype test. It becomes. Against this background, the inventors of the present application have developed the technique of Patent Document 1 so far.

  In the technique of Patent Document 1, the behavior of the resin at the time of injection molding is predicted by the flow analysis of the shell mesh, and the amount of the resin submerged at the weld interface is estimated from the change over time of the flow rate of the resin around the weld line. The quality of the molded product is predicted based on the estimated amount of penetration. According to this technique, it is not necessary to repeatedly perform injection molding while actually changing the mold in order to improve quality, and it becomes possible to determine optimal molding conditions based on the result of flow analysis. The molded product can be designed at a low cost in a short time.

JP-A-2005-74786

  In order to identify factors that affect the occurrence of surface strain in the vicinity of the weld line, the inventors of the present application made a prototype under various molding conditions, and observed the cross section of the weld interface shape and the surface strain in the vicinity of the weld line. The relationship with the aspect was investigated in detail. As a result, it has been found that the aspect of the surface strain appearing on the surface of the molded product is related to the curvature at the central portion in the thickness direction of the weld interface. The sharper the weld interface is in the central part in the thickness direction, the smaller the surface distortion of the surface, and the better the quality of the molded product. Conversely, the flatter the weld interface at the center in the thickness direction, the greater the surface distortion of the surface, and the poorer the quality of the molded product. Based on the above findings, the inventors of the present application have conceived that if the weld interface shape can be predicted by flow analysis, the quality of the molded product can be predicted more accurately.

  Since the weld interface shape is not uniform in the resin thickness direction, it cannot be directly calculated by the shell mesh flow analysis, and it is necessary to perform a solid mesh flow analysis. However, the flow analysis of solid meshes has a drawback that it requires abundant calculation resources and takes a long time for calculation. There is a need for a technique that can predict the quality of a molded product by estimating the weld interface shape from the results of shell mesh flow analysis that can be performed in a short period of time with a small amount of computing resources.

  The present invention provides a technique capable of estimating the quality of a molded product by estimating the weld interface shape from the result of shell mesh flow analysis for a molded product in resin injection molding.

  The present invention is embodied as a method of estimating a weld interface shape inside a weld line generated in resin injection molding. The method is based on the flow analysis of the shell mesh, the step of extracting the position of the weld line from the flow analysis result, and the movement along the flow direction of the resin around the weld line from the flow analysis result. The process of estimating the change over time of the quantity, the process of estimating the change over time of the fluidized bed thickness of the resin around the weld line from the results of the flow analysis, and the flow direction of the resin around the weld line And a step of estimating the weld interface shape based on the change with time of the moving amount and the change with time of the fluidized bed thickness of the resin around the weld line.

  In injection molding, the resin is not cured uniformly in the thickness direction, but gradually cured from the outside in contact with the mold toward the inside. At this time, the outer cured resin does not move any more, but the inner uncured resin moves along the flow direction of the resin according to the collapse of the pressure balance at the weld interface. Therefore, even if the weld interface with which the resin flow is associated is initially flat, the shape is disturbed in the process of curing the resin, and the resin enters.

  In the method of the present invention, based on the result of flow analysis using a shell mesh, the position where the resin flows meet is extracted as the position of the weld line. Then, a temporal change in the amount of movement along the resin flow direction around the weld line and a temporal change in the fluidized bed thickness of the resin around the weld line are estimated. The time-dependent change in the amount of movement along the resin flow direction can be estimated from, for example, the time-dependent change in the resin flow speed included in the flow analysis result. The change with time of the fluidized bed thickness of the resin can be estimated, for example, by taking the difference between the overall thickness of the resin and the thickness of the solidified layer of the resin included in the result of the flow analysis. In the vicinity of the weld line, the resin of the solidified layer that has already hardened does not move any more, and the resin in the fluidized bed that has not yet hardened moves along the flow direction, so the amount of movement along the flow direction changes over time. By combining the change with time of the fluidized bed thickness, the final weld interface shape can be estimated.

  According to the method of the present invention, the weld interface shape can be estimated from the result of the flow analysis of the shell mesh. Compared to the flow analysis of solid meshes, the weld interface shape can be estimated quickly with less computational resources.

  The above method for estimating the weld interface shape is also embodied as an apparatus. The apparatus of the present invention is an apparatus for estimating the shape of a weld interface inside a weld line that occurs in resin injection molding. The device includes a means for analyzing the flow of the shell mesh, a means for extracting the position of the weld line from the result of the flow analysis, and a movement along the flow direction of the resin around the weld line from the result of the flow analysis. A means for estimating the change in quantity over time, a means for estimating the change over time of the fluidized bed thickness of the resin around the weld line from the results of the flow analysis, and a flow direction of the resin around the weld line There is provided means for estimating the weld interface shape based on the change over time in the amount of movement and the change over time in the fluidized bed thickness of the resin around the weld line.

  The method for estimating the weld interface shape is also embodied as a program. The program of the present invention is a program for estimating a weld interface shape inside a weld line generated in resin injection molding. The program analyzes the flow of the shell mesh, extracts the position of the weld line from the flow analysis result, and moves along the flow direction of the resin around the weld line from the flow analysis result. A process that estimates the change over time in the volume, and a process that estimates the change over time in the fluidized bed thickness of the resin around the weld line from the results of the flow analysis, along the flow direction of the resin around the weld line The computer is caused to execute processing for estimating the weld interface shape based on the change over time in the amount of movement and the change over time in the fluidized bed thickness of the resin around the weld line.

  The present invention is also embodied as a method for predicting the quality of a molded product. The method of the present invention is a method for predicting the quality of a molded article in resin injection molding. The method consists of a flow analysis of the shell mesh, a step of extracting the position of the weld line generated in the injection molding from the result of the flow analysis, and a resin flow around the weld line from the result of the flow analysis. The process of estimating the change over time of the moving amount along the direction, the process of estimating the change over time of the fluidized bed thickness of the resin around the weld line from the results of the flow analysis, and the resin around the weld line Estimating the shape of the weld interface inside the weld line based on the change over time in the amount of movement along the flow direction and the change over time in the fluidized bed thickness of the resin around the weld line, and the weld interface shape A step of judging the quality of the molded product based on the above. In this method, when the curvature at the central portion in the thickness direction of the weld interface is large, it is determined that the quality of the molded product is good.

  According to said method, the quality of a molded article is estimated based on the curvature in the center part of the thickness direction of a weld interface. From the investigation results of the inventors of the present application, the greater the curvature at the central portion in the thickness direction of the weld interface, the smaller the surface distortion near the weld line becomes less conspicuous, and the better the quality of the molded product. I know. Therefore, according to said method, the quality of a molded article can be estimated more correctly than before.

  The present invention is also embodied as an apparatus. The method of the present invention is an apparatus for predicting the quality of a molded product in resin injection molding. The apparatus includes means for analyzing the flow of the shell mesh, means for extracting the position of the weld line generated in the injection molding from the result of the flow analysis, and the flow of the resin around the weld line from the result of the flow analysis. Means for estimating the time-dependent change in the amount of movement along the direction, means for estimating the time-dependent change in the thickness of the fluidized bed of the resin around the weld line from the results of the flow analysis, and resin around the weld line Means for estimating the weld interface shape inside the weld line based on the change over time in the amount of movement along the flow direction of the resin and the change over time in the fluidized bed thickness of the resin around the weld line, and the weld interface shape Means for determining the quality of the molded product based on the above. In the apparatus, when the curvature at the central portion in the thickness direction of the weld interface is large, it is determined that the quality of the molded product is good.

  The present invention is also embodied as a program. The program of the present invention is a program for predicting the quality of a molded product in resin injection molding. The program includes the flow analysis of shell mesh, the process of extracting the position of the weld line generated in injection molding from the result of flow analysis, and the flow of resin around the weld line from the result of flow analysis. Processing to estimate the time-dependent change in the amount of movement along the direction, processing to estimate the time-dependent change in the fluidized bed thickness of the resin around the weld line from the results of the flow analysis, and resin around the weld line Processing to estimate the weld interface shape inside the weld line based on the change over time in the amount of movement along the flow direction and the change over time in the fluidized bed thickness of the resin around the weld line, and the weld interface shape The computer is caused to execute processing for judging the quality of the molded product based on the above. In the program, when the curvature at the central portion in the thickness direction of the weld interface is large, it is determined that the quality of the molded product is good.

  According to the present invention, it is possible to estimate the quality of a molded product by estimating the weld interface shape from the result of the flow analysis of the shell mesh for the molded product in resin injection molding.

Hereinafter, preferred embodiments of the present invention will be described.
(Embodiment 1) When the weld interface shape is folded, the quality of the molded product is judged to be better than when the weld interface shape is not folded.

  FIG. 1 is a diagram showing a configuration of a molding quality prediction apparatus 100 according to an embodiment of the present invention. The molding quality prediction apparatus 100 is a computer such as a personal computer or a workstation, and inputs a calculation unit 102 that performs calculation processing, a design data storage unit 112 that stores design data of a molded product shape, and parameters in flow analysis. A parameter input unit 114 and an output unit 116 for outputting the flow analysis result, the estimated weld interface shape, the predicted quality of the molded product, and the like are provided. The calculation unit 102 converts the CAD data of the molded product shape into a shell mesh and performs a flow analysis, a data analysis unit 106 that extracts necessary data from the flow analysis result data, and a weld interface shape. An interface shape estimation unit 108 for estimation and a molding quality prediction unit 110 for predicting the quality of a molded product based on the weld interface shape are provided. Conversion of CAD data to shell mesh and flow analysis are performed by a commercially available CAE software program. Various parameters in the flow analysis, such as the characteristics of the resin used for injection molding, the parameters such as the gate position, the gas vent position, and the pressurization history are input by the parameter input unit 114. The output unit 116 may be a display that displays an image, a printer that prints on paper, or a communication device that communicates with other devices.

FIG. 2 is a flowchart of molding quality prediction processing using the molding quality prediction apparatus 100.
In step S202, CAD data indicating the reference shape of the molded product created by the designer is created. The created CAD data is stored in the design data storage unit 112 of the molding quality prediction apparatus 100.

  In step S204, the flow analysis unit 104 performs the flow analysis by converting the CAD data into a shell mesh. FIG. 3 illustrates a flow analysis model 300 represented by a shell mesh having a plurality of nodes. In the flow analysis, a process is simulated in which the resin injected from the gate positions 302 and 304 flows along the mold and is then cooled and hardened. Through the flow analysis, the position and shape of the weld line 306 where the two resin flows meet are specified. In addition, the flow analysis result includes time series data of the resin flow velocity at each node of the shell mesh and time series data of the solidified layer thickness.

In step S <b> 206, the data extraction unit 106 extracts the shell mesh nodes 308, 310, 312, 314, and 316 located around the weld line 306.
The data extraction unit 106 selects shell mesh nodes 308, 310, 312, 314, and 316 around the weld line 306 based on the distance from the weld line 306 whose position and shape are specified by the flow analysis.
For each of the nodes 308, 310, 312, 314, and 316 extracted as the nodes around the weld line 306, the data extraction unit 106 performs time series data on the resin flow velocity and time series data on the solidified layer thickness. Extract from the flow analysis results.

  In step S208, the interface shape estimation unit 108 estimates changes over time in the amount of movement along the resin flow direction at the shell mesh nodes 308, 310, 312, 314, and 316 extracted in step S206. Assuming virtual particles of the resin in the fluidized bed, the virtual particles move according to the flow of the resin until the resin is cured. Therefore, when the initial resin flow velocity is V1, the virtual particles move by V1 · Δt during the unit time Δt. Therefore, the moving amount along the flow direction of the particles is x1 = V1. Δt. When the flow velocity of the resin reaches V2 after the unit time Δt elapses, the virtual particles move by V2 · Δt during the unit time Δt. Therefore, the amount of movement along the flow direction of the particles is x2. = X1 + V2 · Δt. The interface shape estimation unit 108 performs time analysis data V1, V2,..., Vn of the resin flow velocity on all the shell mesh nodes 308, 310, 312, 314, 316 extracted in step S206, and a flow analysis. , Xn of the amount of movement along the resin flow direction is calculated from the unit time Δt.

  In step S210, the interface shape estimation unit 108 estimates changes over time in the fluidized bed thickness at the shell mesh nodes 308, 310, 312, 314, and 316 extracted in step S206. In the flow analysis, the process in which the resin gradually hardens from the outside in contact with the mold in the injection molding to the inside is simulated, and the flow analysis results show that the resin at each node of the shell mesh Time series data of the overall thickness and time series data of the thickness of the solidified layer are included. The interface shape estimation unit 108 calculates the difference between the time series data of the total resin thickness and the time series data of the solidified layer thickness for all the shell mesh nodes 308, 310, 312, 314, and 316 extracted in step S206. By calculating, time-series data of fluidized bed thickness is obtained.

In step S212, the interface shape estimation unit 108 is based on the time series data of the movement amount along the resin flow direction estimated in step S208 and the time series data of the fluidized bed thickness of the resin estimated in step S210. Estimate the weld interface shape.
FIG. 4 shows how the weld interface shape is estimated. In the following, as shown in FIG. 4A, the resin flow direction is the x direction, and the resin thickness direction is the z direction. The overall thickness of the resin is expressed as z0, and the central portion in the resin thickness direction is set to z = 0.
FIG. 4B shows time-series data of the movement amount along the resin flow direction estimated in step S208. Corresponding to the times t1, t2,..., Tn, movement amounts x1, x2,..., Xn along the resin flow direction at the respective times are estimated. FIG. 4C shows time-series data of the fluidized bed thickness of the resin estimated in step S210. Corresponding to times t1, t2,..., Tn, fluidized bed thicknesses z1, z2,. In FIG. 4C, it is assumed that the curing of the resin proceeds vertically symmetrically across the central portion.
As shown in FIG. 4C, the fluidized bed decreases as the resin cures, and the resin contained in the fluidized bed cures to form a solidified layer. The resin contained in the fluidized bed moves according to the amount of movement along the resin flow direction shown in FIG. 4B, and then hardens to form a solidified layer. . Under such assumption, by evaluating for each position in the thickness direction how much the resin around the weld interface 402 moves along the flow direction until it is cured, The shape of the weld interface 402 that is finally formed can be estimated. In this embodiment, the movement amounts x1, x2,... Along the resin flow direction at times t1, t2,... Are expressed as the fluidized bed thicknesses z1, z2,. ... Are combined to estimate the shape of the weld interface 402 as shown in FIG.

In step S214, the molding quality prediction unit 110 predicts the quality of the molded product from the weld interface shape estimated in step S212.
FIG. 5 shows the result of acquiring the relationship between the weld interface shape and the quality of the molded product by the prototype test. In FIG. 5, the weld interface shape does not fold into one resin (A1 and A2 in FIG. 5), and the weld interface shape folds in the middle of one resin (B1 in FIG. 5). , B2, B3) shows the results of evaluating the quality of the molded product according to the sharpness of the tip. The tip portion of the weld interface is located at the center portion in the resin thickness direction, and the one having a large curvature of the weld interface at the center portion in the thickness direction corresponds to the tip portion being sharp. In FIG. 5, the quality of the molded product is shown in five stages from 1 to 5, and the larger the value, the less the surface distortion near the weld line on the surface of the molded product and the better the quality. . The one where the weld interface shape was folded halfway was better in quality than the one where the weld interface shape was not folded halfway. In addition, the tip of the weld interface is sharp, that is, the curvature at the center of the weld interface in the thickness direction is larger, the tip of the weld interface is rounded, that is, the thickness of the weld interface. The quality was better than that with a small curvature at the center in the vertical direction.

  Such a relationship between the sharpness of the tip of the weld interface and the quality of the molded product is considered to be caused by talc orientation in the resin, as shown in FIG. FIG. 6A illustrates a cross section of a molded product having a rounded tip at the weld interface, and FIG. 6B illustrates a cross section of a molded product having a sharp tip at the weld interface. Yes. As shown in FIG. 6A, the talc 602 in the resin is usually oriented along the resin flow direction, but in the vicinity 604 of the weld interface 600 where the resin flow meets, Instead, the orientation is along the weld interface 600. When the tip of the weld interface 600 is rounded as shown in FIG. 6A, a talc alignment is formed in the vicinity 604 of the weld interface 600 along the resin thickness direction. Since the talc orientation is greatly different between the vicinity 604 of the weld interface 600 and other portions, the shrinkage amount in the thickness direction when the resin is cured is different, resulting in a large surface strain 606 on the surface of the molded product. It is formed. When the tip of the weld interface 610 has a sharp shape as shown in FIG. 6B, talc alignment along the thickness direction of the resin is not so formed in the vicinity 614 of the weld interface 610. Since the talc orientation is not so different between the vicinity 614 of the weld interface 610 and the other part, and the shrinkage amount in the thickness direction when the resin is cured is not so different, the surface of the molded product has a small surface strain 616 as a result. Only formed.

  Based on the above knowledge, in step S214 of FIG. 2, the molding quality prediction unit 110 determines (1) whether or not the weld interface is folded and (2) the curvature at the central portion in the thickness direction of the weld interface. Each is specified, and the quality of the molded product is judged using the evaluation function. The evaluation function is set so that the smaller the value is, the better the molding quality is. The evaluation function is set to have a smaller value when the weld interface is folded halfway than when the weld interface is not folded halfway. The evaluation function is set so as to be smaller as the curvature at the center portion in the thickness direction of the weld interface is larger.

  The weld interface shape estimated by the interface shape estimation unit 108 and the quality of the molded product determined by the molding quality prediction unit 110 are output to the output unit 116.

  According to the molding quality prediction apparatus 100 of the present embodiment, the quality of the molded product can be predicted based on the result of the flow analysis of the shell mesh. Therefore, it is not necessary to repeat the trial injection molding trial and error while changing the actual mold shape. In addition, it is possible to quickly evaluate with less computational resources than when performing flow analysis using a solid mesh.

  The molding quality prediction method of the present embodiment may be a computer-readable program prepared in advance, and is realized by executing the program on a computer such as a personal computer or a workstation. This program is recorded on a computer-readable recording medium such as a hard disk (HD), a flexible disk (FD), a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
Further, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

FIG. 1 is a diagram showing a configuration of a molding quality prediction apparatus 100 according to an embodiment of the present invention. FIG. 2 is a flowchart of the molding quality prediction process according to the embodiment of the present invention. FIG. 3 is a view showing a shell mesh model 300 used for the flow analysis. FIG. 4 is a diagram showing a state of estimating the shape of the weld interface inside the weld line. FIG. 5 is a diagram showing the relationship between the shape of the weld interface and the quality of the molded product. FIG. 6 is a graph showing the relationship between the talc orientation of the resin and the surface strain near the weld line.

Explanation of symbols

100: Molding quality prediction device,
102: Calculation unit 104: Flow analysis unit 106: Data extraction unit 108: Interface shape estimation unit 110: Molding quality prediction unit 112: Design data storage unit 114: Parameter input unit 116: Output unit 300: Model 302, 304: Gate position 306: Weld line 308, 310, 312, 314, 316: Node 400 around the weld line 400: Weld line 402: Weld interface shape 404, 406: Resin flow direction 600, 610: Weld interface 602: Talc 604, 614: Weld Near the interface 606, 626: surface strain

Claims (6)

A method for estimating a weld interface shape inside a weld line generated in resin injection molding,
A process of analyzing the flow of the shell mesh,
A process of extracting the position of the weld line from the result of the flow analysis;
From the result of the flow analysis, a process of estimating the change over time of the amount of movement along the flow direction of the resin around the weld line;
From the results of the flow analysis, a process of estimating the change over time of the fluidized bed thickness of the resin around the weld line;
A method comprising a step of estimating a weld interface shape based on a change over time in the amount of movement along the resin flow direction around the weld line and a change over time in the fluidized bed thickness of the resin around the weld line. . An apparatus for estimating a weld interface shape inside a weld line generated in resin injection molding,
A means to conduct shell mesh flow analysis;
Means for extracting the position of the weld line from the results of the flow analysis;
From the results of the flow analysis, a means for estimating the change over time of the amount of movement along the flow direction of the resin around the weld line;
From the results of the flow analysis, a means for estimating the change over time of the fluidized bed thickness of the resin around the weld line,
An apparatus comprising means for estimating a weld interface shape based on a change over time in the amount of movement along the resin flow direction around the weld line and a change over time in the fluidized bed thickness of the resin around the weld line . A program for estimating a weld interface shape inside a weld line generated in resin injection molding,
Processing to analyze shell mesh flow,
From the results of flow analysis, the process of extracting the position of the weld line;
From the results of the flow analysis, a process for estimating the change over time of the amount of movement along the resin flow direction around the weld line;
From the results of the flow analysis, a process for estimating the change over time of the fluidized bed thickness of the resin around the weld line;
A computer is used to estimate the weld interface shape based on changes over time in the amount of movement along the resin flow direction around the weld line and changes over time in the fluidized bed thickness of the resin around the weld line. A program to be executed. A method for predicting the quality of a molded product in resin injection molding,
A process of analyzing the flow of the shell mesh,
Extracting the position of the weld line generated in the injection molding from the result of the flow analysis; and
From the result of the flow analysis, a process of estimating the change over time of the amount of movement along the flow direction of the resin around the weld line;
From the results of the flow analysis, a process of estimating the change over time of the fluidized bed thickness of the resin around the weld line;
Estimate the shape of the weld interface inside the weld line based on changes in the amount of movement along the flow direction of the resin around the weld line and changes in the fluidized bed thickness around the weld line. And a process of
It has a process to judge the quality of the molded product based on the weld interface shape,
A method in which the quality of a molded article is judged to be good when the curvature at the central portion in the thickness direction of the weld interface is large. An apparatus for predicting the quality of a molded product in resin injection molding,
A means to conduct shell mesh flow analysis;
Means for extracting the position of the weld line generated in the injection molding from the result of the flow analysis;
From the results of the flow analysis, a means for estimating the change over time of the amount of movement along the flow direction of the resin around the weld line;
From the results of the flow analysis, a means for estimating the change over time of the fluidized bed thickness of the resin around the weld line,
Estimate the shape of the weld interface inside the weld line based on changes in the amount of movement along the flow direction of the resin around the weld line and changes in the fluidized bed thickness around the weld line. Means to
It has a means to judge the quality of the molded product based on the weld interface shape,
An apparatus characterized in that the quality of a molded product is judged to be good when the curvature at the central portion in the thickness direction of the weld interface is large. A program for predicting the quality of a molded product in resin injection molding,
Processing to analyze shell mesh flow,
From the result of flow analysis, processing to extract the position of the weld line that occurs in injection molding,
From the results of the flow analysis, a process for estimating the change over time of the amount of movement along the resin flow direction around the weld line;
From the results of the flow analysis, a process for estimating the change over time of the fluidized bed thickness of the resin around the weld line;
Estimate the shape of the weld interface inside the weld line based on changes in the amount of movement along the flow direction of the resin around the weld line and changes in the fluidized bed thickness around the weld line. Processing to
It is for causing a computer to execute processing for judging the quality of a molded product based on the weld interface shape,
A program characterized in that the quality of a molded product is judged to be good when the curvature at the central portion in the thickness direction of the weld interface is large.

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