JPH10154169A - Method for evaluating deformation of molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To show a specific part to be corrected for a molded product that is deformed by its warping, etc., by inputting the molded product model data divided into the finite elements to successively perform the flowing, cooling and warping analyses, deciding a deformed area of the molded product based on the analysis results and displaying a deformed model. SOLUTION: The molded product model data divided into the finite elements are inputted, and the flowing, cooling and warping analyses are successively performed to an input model. Then a deformed area of a molded product is decided based on the analysis results, and a deformed model is displayed. The thickness/shape information is added to the model itself, and the thickness is automatically inputted to every divided finite element. Then the thickness of every element is calculated from the thickness data on the lattice point of the element itself when the model data are divided into the finite elements. Thus, it's possible to show a specific part where the thickness should be changed and also to shorten the time needed for deciding an optimum shape and the optimum molding condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating deformation of a molded article for simulating and evaluating deformation occurring in the molded article.

[0002]

2. Description of the Related Art In an injection molded product, a temperature distribution in a cross section of the molded product due to a temperature difference between a fixed side and a movable side of a mold and the like, and a shrinkage distribution on the molded product due to imbalance of molding pressure and cooling. Warpage is caused by the difference in the flow behavior of the resin and the anisotropy of the shrinkage ratio due to the orientation of the filler and the like.

[0003] For this reason, when determining the shape of the molded product and setting the molding conditions, a deformation simulation of the molded product is performed, and based on the evaluation, the molding conditions and the shape of the molded product are reviewed to determine the optimal model. It is usual to decide. Conventionally, warpage deformation is predicted using a commercially available injection molding analysis system. However, the injection molding analysis system inputs molded article model data and molding conditions as shown in FIG. Then, by performing flow / packing / cooling analysis, the resin pressure, resin temperature, and density distribution in the mold cavity are calculated, and then these data are used to perform warpage analysis and sensitivity analysis. Which of the three factors, the variation in temperature distribution in the cross-section of the molded product, the difference in the distribution of shrinkage on the molded product, and the difference in orientation, which are the causes of the warpage of the molded product, has the greatest effect? Figure out.

Now, if the input model of the shape A shown in FIG. 32 is changed to the shape of B by the warpage analysis, in order to find the cause of this deformation, variations in the temperature distribution in the cross section of the molded product, When the shape shown in C, D, and E is obtained by displaying the effect of any one of the difference in the distribution of the shrinkage and the difference in the orientation of the material higher than the other two,
Since B is recognized as a combination of D and E, the deformation is determined to be caused by a difference in the distribution of shrinkage on the molded product and a difference in orientation.

[0005]

With the practical use of such an analysis, it has become possible to estimate the cause of deformation of the molded product and to take measures by setting guidelines for changing the molding conditions. Such as changing the position of the cooling pipe in the mold,
It is not possible to identify a part of the model to which a measure should be taken.

For example, comparing the model OM before deformation and the model SM after deformation as shown in FIG. 33, the largest displacement from the shape before deformation is A at the upper left corner in the figure. The deformed portion causing the entire deformation is B in the figure. In other words, even if the current analysis shows that the cause of the deformation is the temperature difference between the mold (the fixed side and the movable side), the warpage deformation will not be improved unless the location of the point b to be countermeasured can be specified. However, in the conventional analysis, it was not possible to specify the above-mentioned countermeasure b.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to indicate which part of a molded product deformed due to warpage or shrinkage should be treated. It is an object of the present invention to provide a method for evaluating deformation of a molded article which can be performed.

[0008]

According to the method for evaluating the deformation of a molded product according to the present invention, a model data of a molded product obtained by dividing a finite element is inputted, and a flow, cooling,
The first characteristic is that the warpage analysis is sequentially performed, a deformed portion of the molded product is obtained from the analysis result, and the deformed model is displayed, and the finite element-divided molded product model data is input. The flow, cooling, and warpage analyzes are sequentially performed on the model, and the model to which the analysis results are added is divided into components consisting of a plane portion, a curved surface portion, and a corner portion. The second feature is that the added model is displayed, and furthermore, the finite element-divided molded product model data is input, and the input model is divided into components including a plane portion, a curved surface portion, and a corner portion. The third feature is that the amount of deformation is obtained for each component, then the components to which the amount of deformation is added are combined, the location of the combined model is determined, and the model after deformation is displayed. ing.

[0009] The deformed portion is displayed to indicate a portion to be countermeasured, that is, a portion of the model to which a countermeasure such as a change in wall thickness or a change in a position of a cooling pipe in a mold is to be performed.
In any case, when converting the solid model into a shell data model when inputting the molded article model data, calculate the thickness of each finite element and pass it to the shell model as an attribute. Preferably, the shell data model is converted back to a surface model.

When inputting the wall thickness to each element of the model at the time of inputting the molded article model data, the wall thickness at the portion where the surfaces overlap may be determined by the shape of the overlapping surface and the actual measurement. Then, the deformed part is obtained by rotating the model before deformation and the model after deformed while matching the reference points, based on the displacement amount of each point from the reference position, or before and after the deformation. Is divided into meshes, the angle at each point is calculated from the coordinates of three or more adjacent points, and the angle is calculated based on the change in the inclination, or the mesh is divided into each model before and after deformation. , Or calculated based on the amount of change in the distance between adjacent points or the distance between the centers of gravity of adjacent elements, or perform mesh division on each model before and after deformation, calculate the normal vector at each point,
Calculate the area for each element of each model before and after deformation, or based on the angle made by the vectors,
It can be obtained from the area change rate.

In displaying the deformed model,
It is preferable to present a deformed portion that affects the entire deformation. It is possible to easily and reliably grasp the place where the countermeasure should be taken. When the input model is divided into components, grid points are allocated to the outer surface of the
It is preferable to perform division based on the angle between lattice points equal to or larger than the point. Even an input model having a complicated shape can be easily divided into simple components.

As the amount of deformation for each component, a value obtained from an actual measurement of the deformation of an actual molded product or a value obtained by analyzing the warpage of the components can be used. When combining the components with the added amount of deformation, each component is assumed to be an elastic body with a certain elastic modulus, and the deformation that minimizes the balance of the force and the total elastic energy between the components to be combined is assumed. It is good to give the components and combine them. Combinations can be easily performed regardless of the presence or absence of deformation.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a procedure for the above three features relating to a method for evaluating deformation of a molded article according to the present invention. The first feature is that, as shown in the figure, the finite element-divided molded product model data is input, and the input model is subjected to flow analysis, packing pressure analysis, cooling analysis, and warpage analysis in order, and the analysis is performed. The deformed part of the molded product is obtained by calculation from the result, and the deformed model is displayed.

The second feature is that, as shown in the figure, the finite element-divided molded article model data is input, and the flow analysis, the packing pressure analysis, the cooling analysis, and the warpage analysis are sequentially performed on the input model. Then, the model to which the analysis result is added is divided into components including a plane portion, a curved surface portion, and a corner portion, and a deformed portion is obtained by calculation for each component, and the deformed model is displayed.

Further, as a third feature, as shown in the figure, the finite element-divided molded product model data is input, and the input model is divided into constituent elements consisting of a plane portion, a curved surface portion, and a corner portion. Then, the amount of deformation is obtained for each component, then the components to which the amount of deformation is added are combined, the location of deformation of the combined model is obtained, and the model after deformation is displayed.

Next, each step will be described. The input model is a shell data model when inputting the finite element split molded product model data (commercial injection molding simulation software uses the shell model as an input model)
In the case of, the solid model MD1 is converted into the shell model MD3 via the surface model MD2 as shown in FIG. 2, but when the inner surface, outer surface or neutral surface of the model is set to the shell model MD3, the model itself has a thick wall. Information and shape information are stored, and the thickness is automatically input to each element obtained by the finite element decomposition.

Assuming now that there is a model whose wall thickness varies depending on the location as shown in FIG. 3, it is first determined which of the inner surface, outer surface and neutral surface is to be used as the shell data model for each surface. If the outer surface is the input model, the outer surface of the model is divided into grids, the perpendiculars are dropped from each grid point to the inner surface, and the distance (t1, t2, ...) to the inner surface is calculated, and the distance information is stored at each grid point. Let me know. That is, the grid points are formed in such a manner that the plane A coordinate 1, the thickness 1.5, the plane A coordinate 1, the thickness 2.1, the plane A coordinate 1, the thickness 1.6, the plane A coordinate 2, the thickness 1.7, and so on. It creates a position and distance data file.

When each surface is divided into finite elements, the thickness of each element is calculated from the thickness data of the lattice points included in the element or the lattice points surrounding the element. Now, when the element A and the lattice point are located as shown in FIG. 4, the thickness of the finite element surrounded by the triangle is represented by the thickness information (t1 to t5) of the five lattice points P1 to P5. For example, the average value of the thickness of the lattice points surrounded by the element A is av1, and the average value of the thickness of the outer lattice points (three points) closest to each of the three sides of the element A is av2. Then, the thickness of the element A is determined by (av1 + av2) / 2. In the case of the illustrated example, ((t2 + t5) / 2 + (t1 + t3
+ T4) / 3)) / 2.

As for the method of determining the thickness, as shown in FIG. 5, an intermediate vector Vc of the corresponding surface is calculated by taking the sum of the vectors of the corresponding surfaces, and a direction in which the vector and the inner product become zero (intermediate vector Vc). May be used as the thickness calculation direction. In the case where the lengths of the outer surface and the corresponding surface are different as shown in FIG. 6, when the reference surface is divided, as shown in FIG. 6, the division ratio of the corresponding surface is determined correspondingly,
The distance between the two points may be the thickness.

As a method of determining the corresponding surface, a method of arbitrarily setting while observing the entire shape of the model or a method of modeling in a form in which a correspondence is previously provided at the time of model creation by CAD can be used. The corresponding surface may be determined as follows. That is, when the intersections of the lines perpendicular to the plane A passing through the points P1 to P8 of the plane A and the planes B, C, and D in FIG.
As shown in (b), B, C, D passing through these Q1 to Q8
Draw lines perpendicular to each surface, and these lines are the corresponding points (P
1 through P8), the plane is determined as the corresponding plane for each point if the plane passes through the plane (here, plane A).

When the optimum shape is determined by performing the evaluation using the deformation evaluation method according to the present invention, the shell data model MD3 is returned to the surface model MD2, but has the thicknesses t1, t2, and t3. Shell data model MD
When converting 3 into the surface model MD2, as shown in FIG. 8, there may be several types (A1, A2, A3...), And there is a possibility that an accurate surface model MD3 cannot be restored. Therefore, when converting the surface model MD2 to the shell model MD3, not only the thickness information but also the shape information is given to the shell model MD3 as an attribute, and the shape information is referred to when returning to the surface model MD2. And the correct surface model MD2 is restored. As the shape information in this case, the shape at the portion where the thickness changes is classified and defined into a plurality of types as shown in FIG. 9, and t1-t2: ty is used for the model A3 shown in FIG.
Shape information such as pe1, t2-t3: type2 is provided. Restoring the surface model MD2 with reference to this shape information is performed using the correct surface model MD2.
2 can be obtained with certainty, so that there is no need to recreate the optimally shaped surface model MD2, and conversion to NC data or the like can be performed in a short time.

When the wall thickness is input to each element of the model at the time of inputting the molded article model data, if the model has a shape as shown in FIG. 10, the surfaces S1, S2 and S3 have the wall thicknesses t1 and t2, respectively. , T3.
Actually, the measured value and the analysis value do not match because there is a difference in heat dissipation between the overlapping portion of the surface indicated by the hatched portion in the figure and the non-overlapping portion. For this reason, when inputting an analysis model, the thickness of each surface is not simply defined as t1, t2, and t3, and another thickness setting is performed for the overlapping portion of the surfaces as shown in FIG.

The thicknesses t4 and t5 set at this time are obtained as follows. That is, as shown in FIG. 12, in the overlapping portion of the surfaces, the cross-sectional area of the overlapping portion viewed from the normal direction of one of the overlapping surfaces and the volume of the solid cut in the normal direction at the cross section and the result of actual measurement The thicknesses t4 and t5 are determined from. With respect to a plane having an overlap of the cross-sectional area A and the volume V, measurement (relationship between temperature rise time, cooling time, etc. for each part) is performed with an actual molded product, and a database is created. As shown in FIG. 13 (a), when the temperature of the model having the thickness t1 after the analysis is T1 and the measured temperature is T0, the thickness at the surface overlapping portion of the analysis model is corrected to (T0). t2
-T1) The analysis is performed with the thickness increased by the amount. Actually, a graph as shown in FIG. 13B in which the graph shown in FIG. 13A is drawn with respect to several cross-sectional areas and volumes (cut volumes) is created and stored in a database.

Next, a description will be given of a calculation for obtaining a deformed portion in order to specify the deformed portion. Now, when the model divided into a lattice shape is cut along the lattice lines and the respective cross sections are deformed as shown in FIG.
By rotating the model about a ', b and b' are matched as shown in FIG. At this time, the distance between a and a 'and the adjacent h-h' is calculated, and if the distance is smaller than a preset allowable value, it is determined that the deformation is not performed between b-a-h. Next, c and c 'are matched to calculate the distance between bb' at that time, and if this value is within the allowable value, it is determined that there is no deformation between abc. By repeating this operation, as shown in FIG.
Are matched, ee ', dd', c-
If any of the distances c ′ and bb ′ exceeds the allowable value, it is determined that e ′ before f is the deformation start point.

Similarly, the distance between hh ′ when i and i ′ are made coincident with respect to a and a ′ is sequentially determined.
When k and k ′ are matched as shown in FIG.
If any of j ′, ii ′, and hh ′ exceeds the allowable value, j ′ is determined as the transformation start point. Next, focusing on the newly found deformation start points e and e ′, FIG.
15 (d), the model is rotated to evaluate ff ′ and gg ′, and as shown in FIG. 15 (e), the model is rotated about the j and j ′ points to obtain kk ′ , L ′ ′ are evaluated. It should be noted that the allowable value for determining whether or not deformation is possible depends on the size, shape, and number of mesh divisions of the model. The determination of the allowable value can be made automatically from data such as the size of the model, in addition to a method of arbitrarily inputting a value.

For example, one point (a,
Calculate all displacements at other points when a ') is rotated in accordance with a'), calculate the reference point that minimizes the sum, the rotation angle, and the minimum value of the sum, and evaluate the minimum value of the sum Points (a
, The average of the deformation amount is obtained, and α times the average value (α: determined by the shape and size of the model) is set as the allowable value. Allowable value = α (Σ (distance between two points before and after deformation) /
Σ (number of data)).

FIG. 16 shows another example of an operation for obtaining a deformed portion. When the model is divided into a square grid and a rectangular grid (the model may be divided into finite elements of a triangular mesh), adjacent models may be used. An angle at each point is calculated from coordinates of three or more points. The angle at point P12 is P2-
Evaluation is performed at an angle formed by P12-P22 and P11-P12-P13. 2 shown in FIG. 17 obtained by this method
Evaluate or average each of the two angles θa and θb to obtain P
12, and by applying this to the model OM before deformation and the model SM after deformation (FIG. 18 shows an averaged case), the amounts of change in the angles θ and θ ′ before and after deformation are calculated, and the change is calculated. If the amount exceeds a certain allowable angle, it is determined that there is deformation (warpage) near P12. The allowable angle at this time may be arbitrarily input and set, but the allowable angle = α
(Σ (angle difference before and after deformation) / Σ (number of points)) may be automatically set from the entire angle change amount. Note that α is determined by the shape (curvature) and size of the model.

FIG. 19 shows still another example of a calculation for obtaining a deformed portion. When the model is divided into a square, a rectangular grid, or a finite element of a triangular mesh, the distance between the points is calculated to determine the distance before and after the deformation. The amount of change in the distance (δ1, δ2) is calculated. Alternatively, the center of gravity of the element surrounded by four or three points is obtained by calculation, and the amount of change in the distance between the respective centers of gravity is calculated. If the amount of change exceeds a certain allowable value, it is determined that the point is deformed (contracted). The allowable value may be arbitrarily input and set, but assuming that the allowable value = α (Σ (difference in displacement before and after deformation) / Σ (number of evaluation points)), it is automatically calculated from the distance change between the points. You may make it set. Note that α is determined by the shape and size of the model. Further, by performing the above-described determination of warpage deformation and this determination of contraction deformation, it is possible to determine whether only contraction has occurred or whether both warpage and contraction have occurred.

In the calculation for obtaining the deformed portion, mesh division is performed on each model before and after the deformation, and FIG.
(a) As shown in (b), the normal vectors n1 and n2 at each point are calculated. If the angle θ formed by the vectors n1 and n2 is larger than a certain allowable value, it is determined that the part is deformed. You may decide. The angle theta is ^{θ = cos- -1 (| n1 |} 2 + | n2 | 2 - | n1-n2 | 2/2 | n1
|| n2 |). The allowable value may be arbitrarily input and set, or may be automatically set by calculating both the angle change of each point.

When the angle of change of the point is determined, an equiangular change line (a contour map connecting points having the same angle) is drawn on the model before and after the deformation as shown in FIG. May be specified. As shown in FIG. 22, the area (Sa, Sb) is calculated for each element obtained by dividing the element of each model before and after the deformation, and the area change rate s = (Sb−Sa) / Sa is obtained. If the rate of change s exceeds the allowable value, it may be determined that there is deformation. Although the allowable value may be arbitrarily input and set, the allowable value is automatically set based on the area change rate of each element, assuming that α = (Σ (amount of change in area of each element before and after deformation) / Σ (area of each element)). You may make it set. α is a value determined by the size and shape of the model.

However, only by evaluating the area change rate s,
Even if the contracted portion of the target element can be specified, the location cannot be specified when the element undergoes equal-volume deformation. Therefore, in practice, it is preferable to perform at least one of the above calculation methods for calculating the deformed portion. In displaying the model after the deformation, the display is performed in such a manner as to clearly indicate the deformation location that affects the entire deformation. In other words, instead of showing a portion where the displacement caused by the deformation is large, a portion (a component) where the deformation causing the above-mentioned displacement occurs is shown by, for example, adding a color as shown in FIG. It is.
By displaying in this way, the location where the shape, thickness, etc., of the molded product model must be changed becomes clear,
As a result, it is possible to take appropriate measures.
It is also preferable to color-code the deformed portions according to the degree of influence on the entire deformation. When indicating the deformed portion, it is also preferable to distinguish and display whether the deformation is only the contraction or the deformation caused by both the contraction and the warpage. In FIG. 23, F1 indicates a location where both contraction and warpage occur, and F2 indicates a location where only contraction occurs.

Next, the point of dividing the model or the input model to which the analysis result is added according to the second and third aspects of the present invention into the components including the plane portion, the curved surface portion, and the corner portion will be described. In this division, when dividing by a smaller number than in the case of dividing by a finite element, paying attention to the fact that the deformation pattern depends on the shape of each molded product other than the molding conditions, a representative component having a characteristic shape And a plane part F and a curved part C as constituent elements.
And a corner K are set, and divided as shown in FIG.

In such a division, the plane portion F, the curved surface portion C, and the corner portion K must be discriminated and divided. For example, as shown in FIG. The grid points are allocated to the outer surface, and the angle α between three or more continuous grid points is sequentially obtained. When the angle α suddenly changes, it is assumed that the corner K includes several grid points before and after the angle α, When the angle α is constant at approximately 180 °, the portion is defined as a flat portion F, and the angle α is, for example, 90 ° to 18 °.
When a substantially constant value is maintained in an angle range such as 0 ° or when the value gradually changes within the above range, the portion is regarded as a curved surface portion C.

If the molded product model OM is divided into the elements of the plane portion F, the curved surface portion C, and the corner portion K, the second feature of the present invention is that the above-described calculation for finding the deformed portion is performed. Perform for each element. According to the third feature of the present invention, the amount of deformation is determined for the elements of the plane portion F, the curved surface portion C, and the corner portion K. This is based on flow analysis, pressure-holding analysis, cooling analysis, warpage. In addition to the analysis, if the amount of deformation is obtained based on the previously obtained amount of deformation data of the representative component, the time required for the calculation for obtaining the amount of deformation can be reduced.

As the deformation amount data in this case, for example, data obtained as a function from the ratio between the size before deformation (molded product model) and the size after deformation for each representative element as shown in FIG. 26 is preferable. Can be used. Deformation amount data may be created from a certain molding model and actual measurement data of the actual molded product. The molding resin used for molding of the molded article and the test piece 1 molded under the same molding conditions are divided into a lattice as shown in FIG. 27, and each divided model is divided by using a three-dimensional measuring device, a laser displacement sensor, or the like. The shape measurement is performed to determine the deformation amount data. Since there is no calculation error, a reliable deformation amount data database can be created.

In addition, as shown in FIG. 28, the deformation amount data may be created by obtaining the deformation amount of each component by warping analysis and making the relationship between the model shape and the deformation amount into a database. In this case, the deformation amount data of the elements having various thicknesses can be obtained without the need for a molding experiment. When the deformation amount for each element is obtained, the components F ′, C ′,
The model SM after deformation is obtained by combining K ′ with each other. In this combination, two or more reference points are set on the combination portion of the components to be combined so that these reference points match. Can be combined. However, if the amounts of deformation are different between the components to be combined, two or more reference points may not be able to match. In this case, each component is assumed to be an elastic body having a certain elastic modulus, and the components are deformed so as to minimize the balance of the force between the components to be combined and the total sum of the elastic energies. , And the above reference points are matched and combined. FIG. 30 shows the amounts of deformation of the two components 2 and 3 obtained by dividing the molded article model OM. When only one of the components 2 contracts and deforms, both components 2 ′ and 3 ′ are further deformed. It shows the case where they are combined.

When the combination is completed and the deformed model is determined as described above, the above-described calculation for obtaining the deformed portion is performed on the model. In addition, as described above, a display is provided in a form that presents the portion that causes the entire deformation, to indicate to the operator that the portion is the cause of the deformation and that a countermeasure should be taken.

[0038]

As described above, according to the present invention, a molded article model data obtained by dividing a finite element is input, a flow / cooling / warpage analysis is sequentially performed on the input model, and the molded article is deformed based on the analysis result. In order to find the location and display the deformed model, display the deformed location and take measures against any part of the model, such as changing the wall thickness or changing the position of the cooling pipe in the mold. It is possible to indicate whether or not it is good, so that the time required to determine the optimum shape and the optimum molding conditions can be shortened.

According to the second aspect of the present invention, the model data obtained by dividing the finite element into molded products is input, and the input model is subjected to flow / cooling / warpage analysis sequentially, and the model to which the analysis result is added is converted to a plane Divided into components consisting of parts, curved surfaces and corners, and for each component, the deformation location is determined,
Since the model with the added deformation is displayed, in this case also, the deformed portion can be displayed to indicate a portion to be dealt with, so that the time required to determine the optimum shape and the optimum molding conditions can be reduced.

According to the third aspect of the present invention, the finite element-divided molded product model data is input, and the input model is divided into components having a flat portion, a curved surface portion, and a corner portion. In order to determine the amount of deformation for each, then combine the components to which the amount of deformation has been added, determine the deformation location of the combined model, and display the model after deformation,
Again, the deformed part can be displayed to indicate the place to be countermeasured, so that the time required to determine the optimal shape and optimal molding conditions can be shortened, and each element is divided into representative elements having a characteristic shape In order to determine the amount of deformation taking into account the deformation characteristics due to the shape of the element, the number of divisions is small and the deformation characteristics due to the shape are also taken into account.
Simulation for obtaining the amount of deformation can also be accurately performed in a short time.

In any case, when the solid model is converted into a shell data model when inputting the molded article model data, the thickness of each finite element is calculated and passed to the shell model as an attribute, and the optimum shape is further determined. It is preferable to return the determined shell data model to the surface model. Compared to the conventional method of inputting wall thickness for each element after model data creation, the trouble of inputting wall thickness can be omitted, and mutual conversion between shell data and surface data is automatically performed. It can be carried out.

When inputting the wall thickness to each element of the model at the time of inputting the model data of the molded article, the thickness at the portion where the surfaces overlap is determined by the shape of the overlapping surface and the actual measurement. Since the error caused by the wall thickness at the point becomes small, accurate analysis can be performed.
The calculation of the deformed portion is performed by rotating the model before deformation and the model after deformation while matching the reference points to obtain the deformed portion based on the displacement amount of each point from the reference position, or before and after the deformation. Is divided into meshes, and the angle at each point is calculated from the coordinates of three or more adjacent points, and the angle is calculated based on the change in the inclination. Apply, or obtain based on the amount of change in the distance between adjacent points or the distance between the centers of gravity of adjacent elements, or perform mesh division on each model before and after deformation,
The normal vector at each point can be calculated and obtained based on the angle formed between the vectors, or the area can be calculated for each element of each model before and after deformation, and the area change rate can be obtained. In any case, not a deformation as a whole, but a deformation portion that affects each part can be accurately obtained.

In displaying the deformed model,
By presenting the deformed portions that affect the overall deformation, it is easy to grasp the locations where the countermeasures should be taken, the countermeasures can be easily taken, and the number of simulation iterations that lead to the determination of the optimal model can be reduced. When the input model is divided into components, it is preferable to allocate grid points to the outer surface of the model and perform the division based on the angle between three or more consecutive grid points. Even an input model having a complicated shape can be easily and automatically divided into simple components.

As the amount of deformation for each component, a value obtained by actually measuring the amount of deformation of the actual molded product or a value obtained by analyzing the warpage of the component can be used. In the former case, it is possible to obtain data free from the influence of calculation errors, and in the latter case, it is possible to obtain deformation amount data of various components without the need for a molding experiment. When combining the components with the added amount of deformation, each component is assumed to be an elastic body with a certain elastic modulus, and the deformation that minimizes the balance of the force and the total elastic energy between the components to be combined is assumed. By giving the combination to the constituent elements, the combination of the constituent elements can be easily and accurately performed.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a plurality of examples of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of data conversion among a solid model, a surface model, and a shell model in the same as above.

FIGS. 3 (a) and 3 (b) are explanatory diagrams relating to the same wall thickness.

FIG. 4 is another explanatory diagram relating to the wall thickness of the above.

FIG. 5 is an explanatory diagram of setting of a thickness calculation direction in the above.

FIG. 6 is another explanatory view of the thickness of the above.

FIGS. 7A and 7B are explanatory diagrams related to the determination of a corresponding surface according to the embodiment.

FIG. 8 is an explanatory diagram of conversion from a shell model to a surface model.

FIG. 9 is an explanatory diagram of a shape definition.

FIG. 10 is a perspective view of an example of a model.

FIG. 11 is an explanatory diagram of a wall thickness according to the embodiment.

FIG. 12 is an explanatory diagram of a thickness of the above.

FIGS. 13A and 13B are explanatory diagrams of data relating to wall thickness correction.

FIG. 14 is an explanatory diagram of a cross-sectional shape before and after deformation.

FIGS. 15 (a), (b), (c), (d), and (e) are explanatory diagrams of an operation for obtaining a deformation starting point due to rotation.

FIG. 16 is a perspective view of an example of an operation for obtaining a deformed portion.

FIG. 17 is an explanatory diagram of the above.

FIG. 18 is an explanatory diagram of the above.

FIG. 19 is an explanatory diagram of another example of an operation for obtaining a deformed portion.

FIGS. 20 (a) and (b) are explanatory views of still another example of the operation for obtaining a deformed portion.

FIG. 21 is an explanatory diagram of another example of an operation for obtaining a deformed portion.

FIG. 22 is an explanatory diagram of still another example of the operation for obtaining a deformed portion.

FIG. 23 is an explanatory diagram of display of a deformed model.

FIGS. 24A and 24B are explanatory diagrams of division into representative elements.

FIGS. 25 (a), (b) and (c) are explanatory diagrams of a dividing method.

26 (a) to (d) are perspective views of a plurality of examples of representative elements.

FIG. 27 is an explanatory diagram relating to an example of creating deformation amount data.

FIG. 28 is a flowchart related to another example of creating deformation amount data.

FIG. 29 is an explanatory diagram of a combination of elements after deformation.

FIG. 30 is an explanatory diagram of a combination of elements.

FIG. 31 is a flowchart of a conventional example.

FIG. 32 is an explanatory diagram of an input model, a model after warpage analysis, and a model after sensitivity analysis.

FIG. 33 is an explanatory diagram showing a modification.

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[Procedure amendment]

[Submission date] March 10, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 14

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

[0003] For this reason, when determining the shape of the molded product and setting the molding conditions, a deformation simulation of the molded product is performed, and based on the evaluation, the molding conditions and the shape of the molded product are reviewed to determine the optimal model. It is usual to decide. Conventionally, warpage deformation is predicted using a commercially available injection molding analysis system. However, the injection molding analysis system inputs molded article model data and molding conditions as shown in FIG. and, by performing flow-holding pressure and cooling analysis, the resin pressure and the resin temperature in the mold cavity, and the density distribution was calculated, then by performing the reaction Ri analysis and sensitivity analysis using these data The anti- molded product
Variation in temperature distribution in the cross section of the molded product
It grasps which factor has the most influence among the three kinds of differences in the distribution of shrinkage on the molded article and the difference in orientation.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

Now, if the input model of the shape A shown in FIG. 32 is changed to the shape of B by the warpage analysis, in order to find the cause of this deformation, variations in the temperature distribution in the cross section of the molded product, When the shapes shown in C, D, and E can be obtained by displaying one of the influences of the difference in the shrinkage ratio distribution and the difference in orientation higher than those of the other two, B becomes D Therefore, it is determined that the deformation is caused by the difference in the shrinkage distribution on the molded article and the difference in the orientation.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

As the amount of deformation for each component, a value obtained from an actual measurement of the deformation of an actual molded product or a value obtained by analyzing the warpage of the components can be used. In combining the components by adding the amount of deformation, assumes an elastic body having a constant modulus in each component, the sum of the elastic energy is minimized with the balance of forces between the components to be combined can take It is good to give a modification to a component, and to perform combination. Combinations can be easily performed regardless of the presence or absence of deformation.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

Next, each step will be described. The input model is a shell data model when inputting the finite element split molded product model data (commercial injection molding simulation software uses the shell model as an input model)
In the case of, the solid model MD1 is converted into the shell model MD3 via the surface model MD2 as shown in FIG. 2, but when the inner surface, outer surface or neutral surface of the model is set to the shell model MD3, the model itself has a thick wall. Information and shape information are provided so that the wall thickness is automatically input to each element obtained by dividing the finite element.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

Assuming now that there is a model whose wall thickness varies depending on the location as shown in FIG. 3, it is first determined which of the inner surface, outer surface and neutral surface is to be used as the shell data model for each surface. If the outer surface is the input model, the outer surface of the model
The lattice division, and calculates the distance (t1, t2, ...) from each lattice point to the inner surface down the perpendicular to the inner surface and allowed to have that distance information to each lattice point. That is, the grid points are formed in such a manner that the plane A coordinate 1, the thickness 1.5, the plane A coordinate 1, the thickness 2.1, the plane A coordinate 1, the thickness 1.6, the plane A coordinate 2, the thickness 1.7, and so on. It creates a position and distance data file.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

In the calculation for obtaining the deformed portion, mesh division is performed on each model before and after the deformation, and FIG.
(a) As shown in (b), the normal vectors n1 and n2 at each point are calculated. If the angle θ formed by the vectors n1 and n2 is larger than a certain allowable value, it is determined that the part is deformed. You may decide. The angle ^{θ θ = cos -1 (| n1} | 2 + | n2 | 2 - | n1-n2 | 2/2 | n1 |
| N2 |). The allowable value may be arbitrarily input and set, or may be automatically set by calculating from the angle change amount of each point.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction contents]

In addition, as shown in FIG. 28, the deformation amount data may be created by obtaining the deformation amount of each component by warping analysis and making the relationship between the model shape and the deformation amount into a database. In this case, the deformation amount data of the elements having various thicknesses can be obtained without the need for a molding experiment. When the deformation amount for each element is obtained, the components F ′, C ′,
The model SM after deformation is obtained by combining K ′ with each other. In this combination, two or more reference points are set on the combination portion of the components to be combined so that these reference points match. Can be combined. However, if the amounts of deformation are different between the components to be combined, two or more reference points may not be able to match. In this case, assuming that an elastic body having a constant modulus in each component, configured so that the sum of the bullet <br/> energy with the balance of forces between the components to be combined can be taken is minimized By deforming the elements, the reference points are matched and combined. FIG. 30 shows the amount of deformation of two components 2 and 3 obtained by dividing the molded article model OM. When only one of the components 2 is warped , both components 2 ′ and 3 ′ are further deformed. It shows the case where they are combined.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction contents]

As the amount of deformation for each component, a value obtained by actually measuring the amount of deformation of the actual molded product or a value obtained by analyzing the warpage of the component can be used. In the former case, it is possible to obtain data free from the influence of calculation errors, and in the latter case, it is possible to obtain deformation amount data of various components without the need for a molding experiment. In combining the components by adding the amount of deformation, assumes an elastic body having a constant modulus in each component, the sum of the elastic energy is minimized with the balance of forces between the components to be combined can take By giving a modification to the components and performing the combination, it is possible to easily and accurately combine the components.

[Procedure amendment 10]

[Document name to be amended] Drawing

[Correction target item name] Fig. 25

[Correction method] Change

[Correction contents]

FIG. 25

[Procedure amendment 11]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 33

Claims (14)

[Claims] 1. A molded product model data obtained by dividing a finite element is input, flow / cooling / warpage analysis is sequentially performed on the input model, a deformed portion of the molded product is obtained from the analysis result, and the deformed model is displayed. A method for evaluating deformation of a molded article, characterized in that: 2. A model data obtained by dividing a finite element into molded products is input, and flow / cooling / warpage analysis is sequentially performed on the input model. A method for evaluating the deformation of a molded article, wherein the method comprises the steps of dividing a component into components, obtaining a deformation portion of each component, and displaying a model to which the deformation is added. 3. The molded product model data obtained by the finite element division is input, and the input model is divided into components including a plane portion, a curved surface portion, and a corner portion, and a deformation amount is obtained for each component. A method for evaluating deformation of a molded product, comprising: combining constituent elements to which a deformation amount has been added; obtaining a deformed portion of the combined model; and displaying the deformed model. 4. When a solid model is converted into a shell data model upon input of molded article model data, the thickness of each finite element is calculated and passed to the shell model as an attribute. The method according to claim 1, wherein the data model is returned to a surface model. 5. A method for inputting a wall thickness to each element of a model when inputting molded article model data, wherein a wall thickness at a portion where a surface overlaps is determined by a shape of the overlapping surface and an actual measurement. The method for evaluating deformation of a molded product according to claim 1. 6. A deformed portion is obtained based on a displacement amount of each point from a reference position by rotating a model before deformation and a model after deformation while matching reference points. Item 4. The method for evaluating deformation of a molded article according to item 1, 2, or 3. 7. A mesh division is performed on each model before and after deformation, an angle at each point is calculated from coordinates of three or more adjacent points, and a deformation portion is obtained based on a change amount of the inclination. Claim 1 or 2
Or the method for evaluating deformation of a molded article according to 3. 8. The method according to claim 1, wherein a mesh is divided for each of the models before and after the deformation, and a deformed portion is obtained based on a variation of a distance between adjacent points or a distance between centers of gravity of adjacent elements. Or the method for evaluating deformation of a molded article according to 2 or 3. 9. The method according to claim 1, wherein mesh division is performed on each of the models before and after the deformation, a normal vector at each point is calculated, and a deformed portion is obtained based on an angle formed by the vectors. Or the method for evaluating deformation of a molded article according to 2 or 3. 10. The method according to claim 1, wherein an area is calculated for each element of each model before and after the deformation, and a deformation portion is obtained based on the area change rate. Method for evaluating deformation of molded products. 11. When displaying a model after deformation,
4. The method for evaluating deformation of a molded product according to claim 1, wherein a deformation location affecting the overall deformation is presented. 12. The method according to claim 2, wherein, when dividing the input model into components, grid points are allocated to the outer surface of the model and the model is divided based on angles between three or more successive grid points. 3. The method for evaluating deformation of a molded article according to 3. 13. The method according to claim 3, wherein the amount of deformation for each component is obtained from an actual measurement of the amount of deformation of the actual molded product or obtained by analyzing the warpage of the component.
A method for evaluating deformation of a molded article as described. 14. Assuming that each component is an elastic body having a certain elastic modulus, a combination in which the balance of force between the components to be combined and the total sum of the elastic energies are minimized is given to the components to combine the components. 4. The method for evaluating deformation of a molded article according to claim 3, wherein the method is performed.