JP2005330141A - Press molding simulation device, press molding simulation method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press molding simulation device by which the simulation result having sufficiently satisfied practical precision is attained while the computation scale is reduced. <P>SOLUTION: The press molding simulation apparatus estimating the shape of a molding obtained by heating a forming mold and a base material and press molding is constituted so as to be provided with a deformation analysis model forming means 12 in which the mold is defined as a rigid surface model and the base material is defined as a solid element model and an expansion conversion means 13 in which the mold and/or the base material as the deformation analysis model are thermally deformed corresponding to respective coefficient of linear thermal expansion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a press molding simulation apparatus, a press molding simulation method, and a program capable of obtaining a simulation result that can sufficiently satisfy a practical accuracy while reducing a calculation scale.

  In recent years, aspherical lenses have been widely used to reduce the size and weight of optical devices, and prisms with lens functions have been desired mainly in the field of digital cameras. An optical element having such a complicated surface shape is difficult to manufacture by grinding and polishing, and is generally manufactured by press-molding a material such as heat-softened glass.

  In order to manufacture a high-precision optical element such as an aspheric lens by press molding, it is necessary to test a number of molding conditions and mold shapes and set them to an optimum state. However, it takes a lot of time and money to actually prepare a mold, adjust the molding conditions, perform molding, and prototype and evaluate the molded product. Therefore, in recent years, a simulation technique related to a molding process at the time of molding an optical element has attracted attention, and simulation analysis related to the molding process is performed to set an optimal molding condition and an optimal mold shape.

  For example, in Japanese Patent Application Laid-Open No. 9-156937, in a stress deformation analysis, after a glass material is pressed with a mold, it is determined whether the glass material and the mold are fixed or separated during cooling. If it is determined that the glass material and the mold are slipping, an analysis is performed using an optical element accuracy prediction system that advances the calculation, and the accuracy of the optical function surface of the optical element is determined based on the analysis result. If it is determined that the accuracy is poor in this evaluation, each molding condition is revised based on the degree of influence of each molding condition on the accuracy failure occurring in the optical element, and the optical element accuracy is revised based on each revised molding condition. When the analysis by the prediction system is performed and it is determined that there is no poor accuracy in the evaluation, there is an optical element molding method that sets each molding condition as the optimum molding condition. It is draft.

  In JP-A-2003-11199, heat transfer analysis means for performing heat transfer analysis of a mold and a molded product, and flow analysis means for performing thermofluid analysis of filling pressure keeping cooling behavior of molten resin in the mold, An injection molding process simulation apparatus for predicting the shape accuracy of a molded product, comprising: a structural analysis means for performing structural analysis of a mold and a molded product, the heat transfer analysis of the mold and the molded product, and the heat of the molded product A fluid temperature analysis is performed alone or in combination to provide a pressure temperature calculation means for calculating the temperature of the mold and the pressure and temperature of the molded product, and the structural analysis means uses the calculated pressure and temperature as initial values. As a result, considering the mold and the molded product at the same time, the structural analysis considering the mold constraint between the mold and the molded product and the viscoelastic properties of the resin is performed, and the shape accuracy of the molded product that deforms due to thermal shrinkage is calculated. Injection molding process simulation equipment And the like have been proposed.

In addition, as a conventional press molding simulation for optimally designing the shape of a material or a mold based on the result of predicting the shape of a molded product, those proposed in Japanese Patent Application Laid-Open Nos. 2002-97025 and 2003-40629 are available. is there.
JP-A-9-156937 JP 2003-11199 A JP 2002-97025 A JP 2003-40629 A

  In order to improve the accuracy of simulation results in conventional press forming simulations, it is conceivable to increase the number of division elements by strictly modeling the mold and material, but if the number of division elements is increased, the simulation calculation The scale becomes enormous, and depending on the model, the calculation time may exceed 100 days. Therefore, in order to reduce the calculation scale while ensuring the accuracy of the simulation results, conventionally, only the molding surface as designed by the molding die has been modeled as a rigid surface that is not thermally deformed at all.

  However, the actual phenomenon is that when the molding surface processed according to the design of the mold is heated to the molding temperature, the molding surface is thermally deformed according to the linear expansion coefficient of the mold material, and the material is molded with this thermally deformed molding surface. Has been. The thermal deformation becomes more prominent as the difference between the room temperature and the molding temperature is larger, and the molded product having a larger dimension is more prominent. Therefore, if only the molding surface of the mold is modeled as a rigid surface, even if the mold reaches the molding temperature, a simulation is performed with the shape as designed without any thermal deformation. There is a problem that sufficient accuracy cannot be obtained in the simulation result.

  Here, in Japanese Patent Laid-Open No. 9-156937 described above, modeling is performed in consideration of thermal expansion in all components including the mold and the glass material. However, this makes the calculation scale of the simulation enormous and practical. There is a problem that simulation results cannot be obtained in a short calculation time.

  In Japanese Patent Application Laid-Open No. 2003-11199 described above, the mold is properly used as an elastic body or a rigid body by simulation. However, regarding the analysis of a part that is considered to be greatly affected by thermal deformation, the deformation is considered as an elastic body. For this reason, there exists a problem that a calculation scale becomes large in the limit which simulates using a shaping | molding die as an elastic body.

  On the other hand, in the conventional press molding simulation described above, it is impossible to predict the molding defect in which the transfer is not continuously obtained from the center of the molding surface, that is, the occurrence of air accumulation, and in this respect the reliability of the simulation result is There was also a problem of being low. In addition, from the viewpoint of rigorously modeling conventional components, it is also possible to model the atmospheric gas in the mold and predict the occurrence of air pools. There is a problem that simulation results cannot be obtained in a reasonable calculation time.

  The present invention has been made in view of the above problems, and a press molding simulation apparatus, a press molding simulation method, and a press molding simulation method capable of obtaining a simulation result capable of sufficiently satisfying practical accuracy while reducing the calculation scale. The purpose is to provide a program.

  In order to achieve the above object, a press molding simulation apparatus according to the present invention is a press molding simulation apparatus for predicting the shape of a molded product obtained by heating and pressing a molding die and a material. In addition to the surface model, the material is a solid element model, and the mold and / or material as the deformation analysis model is thermally deformed according to the respective linear expansion coefficient to perform simulation.

  Preferably, when the shape of the molded product is axisymmetric, the simulation is performed by thermally deforming only one of the radial direction and the axial direction of the mold and / or the material according to the respective linear expansion coefficient. To do.

  Preferably, when the shape of the molded product is non-axisymmetric, only one of the X, Y and Z directions in the orthogonal coordinate system of the mold and / or material is thermally deformed according to the respective linear expansion coefficient. When the shape of the molded product is non-axisymmetric, the linear expansion is performed in any of the X, Y, and Z directions in the orthogonal coordinate system of the mold and / or material. The simulation is performed by thermal deformation according to the rate.

  Preferably, the difference between the linear expansion coefficients of the mold and the material is the linear expansion coefficient of either of the mold or the material, and either the mold or the material is thermally deformed according to the linear expansion coefficient. The simulation is performed.

  In order to achieve the above object, another press molding simulation apparatus of the present invention is a press molding simulation apparatus for predicting the shape of a molded product obtained by press molding by heating a mold and a material. Based on the calculation result of the deformation analysis process, the deformation analysis is performed using the mold and the material as the analysis model, and the molding failure in which the transfer of the mold to the material is not continuously performed from the inside to the outside. This is a configuration to judge.

  Preferably, the molding defect is determined based on a force acting between the mold and the material in the deformation analysis process, or the molding defect is used as position information of the outer shape of the material in the deformation analysis process. It is set as the structure judged based on.

  In order to achieve the above object, a press molding simulation method of the present invention is a press molding simulation method for predicting the shape of a molded product obtained by heating and pressing a molding die and a material. In addition to the surface model, the material is a solid element model, and the molding die and / or the material as the deformation analysis model is thermally deformed according to the respective linear expansion coefficient for simulation.

  In order to achieve the above object, another press molding simulation method of the present invention is a press molding simulation method for predicting the shape of a molded product obtained by press molding by heating a mold and a material. Based on the calculation result of the deformation analysis process, the deformation analysis is performed using the mold and the material as the analysis model, and the molding failure in which the transfer of the mold to the material is not continuously performed from the inside to the outside. Judgment is made.

  In order to achieve the above object, the program of the present invention is a program for causing a computer to execute a press molding simulation for predicting the shape of a molded product obtained by heating and pressing a molding die and a material. The computer is processed with a rigid surface model, the material is a solid element model, and the mold and / or material as a deformation analysis model is thermally deformed according to the respective linear expansion coefficient and simulated. I am trying to make it.

  In order to achieve the above object, another program of the present invention is a program for causing a computer to execute a press molding simulation for predicting the shape of a molded product obtained by heating and pressing a mold and a material. In addition, the deformation analysis is performed using the mold and the material as a deformation analysis model, and the molding failure in which the transfer to the material of the mold is not continuously performed from the inside to the outside, the calculation result of the deformation analysis process Judgment is based on this.

  According to the press molding simulation apparatus, the press molding simulation method, and the program of the present invention, both or one of the mold and the material is thermally deformed according to the coefficient of linear expansion, and a rigid surface model is obtained by a value obtained by thermally deforming the mold. As a result, it is possible to perform a press forming simulation in accordance with an actual phenomenon, and a simulation result with sufficiently practical accuracy can be obtained with a model having a small calculation scale.

  Also, in the process of deformation analysis, based on the force acting between the mold and the raw material, or the position information of the outer shape of the raw material, a molding failure where transfer is not continuously obtained from the center of the molding surface, that is, Air accumulation can be easily determined, and the reliability of simulation results can be improved without increasing the calculation scale.

  Hereinafter, a press forming simulation apparatus, a press forming simulation method, and a program according to an embodiment of the present invention will be described with reference to the drawings. First, the principle configuration of the press molding simulation apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a principle configuration diagram of a press forming simulation apparatus according to the present embodiment.

  In the figure, reference numeral 1 denotes a press molding simulation apparatus, which is a storage means 11, a deformation analysis model creation means 12, an expansion conversion means 13, a deformation analysis means 14, a press time measurement means 15, and an air clogging determination means. 16. Note that the input / output device 26 and the display device 27 in FIG.

  The storage means 11 stores the set values relating to the molding conditions such as the material property data of the raw material and the mold, the two-dimensional or three-dimensional shape data of the mold and the raw material, and the molding temperature T (° C.). Input from the operation input unit 25 (see FIG. 2) and store.

  The deformation analysis model creating means 12 creates a rigid surface model of the mold and a solid element model of the material based on the shape data of the mold and the material. As the deformation analysis model creation means 12, for example, an analysis preprocessor can be applied.

  Here, the rigid surface model of the mold is obtained by dividing only the transfer surface in contact with the material in the mold by the rigid surface element, and the solid element model of the material is a two-dimensional or three-dimensional material as a whole of the solid. It is divided by elements. In the following description, these may be collectively referred to simply as a deformation analysis model.

  The expansion conversion means 13 heat-deforms one or both of the rigid surface model of the mold and the solid element model of the material created based on the design value based on the molding temperature and the linear expansion coefficient of the material. That is, the expansion conversion means 13 performs modeling by converting the coordinates of these deformation analysis models into coordinates after thermal deformation at the molding temperature.

  Based on the deformation analysis model, the deformation analysis means 14 analyzes the deformation of the material when a press load is applied by the finite element method. Moreover, the press time measuring means 15 measures these times based on the setting of the determination timing of the air accumulation determining means 16 described later and the setting of the press time.

  The air accumulation determination means 16 calculates whether or not air accumulation has occurred based on the contact pressure for each node of the mold and the material as a deformation analysis model. That is, when the present inventors numerically analyzed the contact pressure generated between the mold and the material in the calculation process of the simulation for each node divided into these elements, the inside of the mold or the material (the center) The contact pressure of the node located outside before the node located on the side) does not become larger than 0 (MPa), and on the contrary, the contact pressure of the node located outside before the node located inside It has been confirmed that air clogging occurs in the molded product when becomes larger. Therefore, the presence or absence of air accumulation is calculated by the air accumulation determination means 16 based on the contact pressure for each node of the mold and the material as the deformation analysis model.

  Next, the hardware configuration of the above-described press molding simulation apparatus will be described with reference to FIG. FIG. 2 is a hardware configuration diagram of the press molding simulation apparatus.

  In the figure, 21 is a CPU, 22 is a ROM, 23 is a RAM, 24 is a hard disk device, 25 is an operation input unit, 26 is the input / output device, and 27 is the display device. These CPU 21, ROM 22, RAM 23, hard disk device 24, operation input unit 25, image output device 26 and display device 27 are all connected to a bus 28 so that data can be exchanged between them.

  A CPU (Central Processing Unit) 21 is a central processing unit that controls operation of the press molding simulation apparatus. A ROM (Read Only Memory) 22 is a memory in which a control program to be executed by the CPU 21 is stored in advance, and the CPU 21 executes this control program to control the operation of the press molding simulation apparatus. A RAM (Random Access Memory) 23 is a memory used as a temporary storage area for various data and as a work memory when the CPU 21 executes a control program stored in the ROM 22 as necessary. .

  The hard disk device 24 is used as a database for sequentially storing calculation results of element units (or node units) in the deformation analysis model. The above-described control program is stored in advance in the hard disk device 24 instead of being stored in the ROM 22, and the CPU 21 reads the control program from the hard disk device 24 when the press molding simulation apparatus is activated, and the RAM 23 May be temporarily stored, and then the control program may be read from the RAM 23 and executed to control the operation of the entire press molding simulation apparatus.

  The operation input unit 25 includes input devices such as a keyboard and a mouse operated by an operator who uses the press molding simulation device, and acquires the status of operations performed on these input devices.

  The input / output device 26 receives information input from the outside, for example, data of the two-dimensional or three-dimensional shape of the material and the mold created by the CAD system, and sends the information to the CPU 21, or the CPU 21 For example, a simulation result output by the deformation analysis model is performed.

  The input / output device 26 is a portable type such as an FD (Floppy (registered trademark) Disk), a CD-ROM (Compact Disc-ROM), a DVD-ROM (Digital Versatile Disc-ROM), or an MO (Magneto-Optics) disk. A recording medium reading and writing device is used. Further, an interface device for exchanging these input / output information with other devices via a communication network may be provided as the input / output device 26.

  The display device 27 performs display instructed by the CPU 21, and is, for example, a device using a CRT (Cathode Ray Tube) or an LCD (Liquid Crystal Display). The display device 27 displays the simulation result based on the above-described deformation analysis model as an image that can be visually recognized by graphics software.

  The hardware configuration shown in FIG. 2 is provided in many computer systems having a standard configuration. Therefore, the present invention can be implemented by such a computer system.

  Next, a first example including a press forming simulation method and a program according to the present embodiment will be described with reference to FIGS. FIG. 3 is a partial cross-sectional view showing a molding machine used for manufacturing an actual optical element. FIG. 4 is a partial sectional view in the radial direction with the actual mold and the rotation axis of the material as a boundary. FIG. 5 is a flowchart showing the operation procedure or processing contents of the press forming simulation method and program according to the first embodiment. 6 is an explanatory view showing a deformation analysis model of the mold and the material shown in FIG. FIGS. 7A, 7B and 7C are explanatory views showing the process from the start to the end of the deformation analysis model.

  Note that the press molding simulation method and program procedures and processes described below are realized by the CPU 21 executing the control program of the press molding simulation apparatus described above.

  In the first embodiment, a molding of a glass concave meniscus aspheric lens (optical element) used for a digital camera lens that secures desired performance such as MTF (Modulation Transfer Function) will be considered.

[Prerequisites]
First, the configuration of an actual molding machine that performs press molding simulation in the first embodiment will be described with reference to FIGS. 3 and 4. The mold includes a nest 31 having a molding surface, a mold die 32 that supports the nest 31 from the periphery, a die plate 33 that supports the nest 31 and an end surface of the mold die 32, and an upper mold portion is a fixed shaft above the molding machine. At the lower end, the lower mold part is attached to the upper end of the movable shaft below the molding machine via a heat insulating cylinder 34.

  A driving device and a load detection device 35 are installed below the movable shaft, and can be clamped, pressurized, and opened by the vertical movement of the lower mold part during molding. In addition, a transparent quartz tube 36 is attached around the upper and lower mold parts, and the upper and lower ends of the transparent quartz tube 36 are brought into contact with the seal plate 37, thereby forming a molding chamber having airtightness around the molding die. Forming. An infrared lamp unit 38 is attached around the transparent quartz tube 36, and the mold is heated together with a reflection mirror disposed behind the infrared lamp unit 38. Inside the upper shaft (fixed shaft) and the lower shaft (moving shaft), there is a gas supply channel 39 for introducing dry nitrogen gas into the back of the die plate 33 in the molding chamber to cool the upper die and the lower die. It is formed. In addition, 40 shown in FIG. 4 is the glass blank which is a raw material.

[Shape data]
From the design values of the concave meniscus aspheric lens described above, the initial design of the mold and material (glass blank) is performed using the values of the aspheric coefficient, curved radius of curvature, wall thickness, functional effective diameter, glass material, etc. The CAD system defined the shapes of these molds and materials.

[Material property data]
Physical property values necessary for executing press molding simulation with these shapes are prepared. For the mold, a cemented carbide material of 4.9 × 10 ⁻⁶ (/ K) was used as the linear expansion coefficient. As for the materials, the elastic properties are 89.1 (GPa), Poisson's ratio 0.247, and the linear expansion coefficient is 8.8 × 10 ⁻⁶ (/ K), which are physical properties of glass material L-BAL42 (manufactured by OHARA INC.). ) Was used. In the first embodiment, the material is handled as an elastic body model. Although the friction coefficient acting between the mold and the material is 0.4, the friction coefficient is not limited to 0.4.

[Molding condition]
In addition, molding conditions such as a room temperature of 25 (° C.), a molding temperature of 600 (° C.), and a press load of 1000 (N) were defined.

[Press molding simulation]
Subsequently, the press molding simulation according to the first embodiment is started. First, the shape data, material property data, and setting values of the molding conditions described above are read by a computer system or the like (see S1 to S3 in FIG. 5).

  Then, the analysis preprocessor (deformation analysis model creation means) creates a deformation analysis model of the mold and the material based on the shape data (see S4 in FIG. 5). As described above, the deformation analysis model is a rigid surface model of a mold and a solid element model of a material. In the first embodiment, since the optical element (concave meniscus aspherical lens) to be subjected to the press molding simulation is rotationally symmetric, the two-dimensional rotational axis symmetric finite element method deformation analysis that performs calculation only with a symmetric cross section. The model was adopted. As a result, the calculation load can be greatly reduced.

  Next, the transformation analysis model is coordinate-transformed based on the linear expansion coefficient (see S5 in FIG. 5). The processing will be described by taking a rigid surface model of the molding die as an example. As shown in FIG. 6, the rigid surface models of the upper die and the lower die constituting the molding die are created based on the design values. It is represented by coordinates 51, 52 with the top of the surface as the origin (0, 0).

These coordinates 51 and 52 are changed according to the linear expansion coefficient only in the radial direction using the linear expansion coefficient of the mold, for example, 4.9 × 10 ⁻⁶ (/ K) of the cemented carbide material. The change of the coordinate by the linear expansion coefficient can be calculated from the following equation (1). As a result, the coordinates 51 and 52 are changed as the coordinates 53 and 54, respectively.

However, X: coordinates after conversion (length after conversion), X ₀ : coordinates before conversion (representative length), α: linear expansion coefficient, T: molding temperature (600 ° C.), T ₀ : room temperature (25 ℃)
Finally, the rigid surface model of the mold is redefined based on the shape data in which the radial coordinate is changed. Similarly, coordinate conversion based on the linear expansion coefficient of 8.8 × 10 ⁻⁶ (/ K) is performed for the solid element model of the material.

  Next, deformation analysis is performed based on the deformation analysis model after the coordinate conversion (see S6 in FIG. 5). As shown in FIG. 7A, the material is placed between the upper die and the lower die in the above-described deformation analysis model, and the molding temperature 600 (° C.) is applied to the entire material using the material property values. A press molding simulation was applied uniformly, and the press load was set to 1000 (N), and the press process up to the desired thickness was calculated at the molding temperature during the manufacturing process of the glass press lens. For the press molding simulation, general-purpose finite element method analysis software ABAQUS / Standard (manufactured by ABAQUS. Inc) was used.

  Usually, the calculation up to the end of molding is carried out by deformation analysis software by dividing the time appropriately for the convenience of the software, but in the first embodiment, transfer is not continuously obtained from the center of the molding surface during the calculation. In order to detect an air clogging which is a molding defect, calculation is performed every 5 seconds (see S7 in FIG. 5). In the first embodiment, the determination interval for detecting air pockets is 5 seconds, but it can be changed according to the model as appropriate.

  Here, the coordinates of the material and the contact pressure are calculated (see S8 in FIG. 5), and if the predetermined press time (tmax) has not yet elapsed (see S9 in FIG. 5), the presence / absence of air accumulation is determined ( (See S10 in FIG. 5). That is, if the contact pressure (MPa) of the node located outside before the node located inside (center side) of the material increases, it is determined that there is air accumulation in the molded product, otherwise Determines that there is no air accumulation.

  As a result, when it is determined that there is no air accumulation, the steps after the above-described deformation analysis (see S6 in FIG. 5) are repeated. If it is determined that there is air accumulation, the shape of the material is changed, and the steps after reading the shape data (see S3 in FIG. 5) are repeated. Finally, if no air accumulation is detected until the predetermined press time (tmax) elapses, the present press molding simulation ends, and a shape of the material that does not cause molding defects is obtained.

  In the first embodiment, as shown in FIG. 7B, since the air pocket 55 is detected during the calculation of the deformation analysis, the shape of the material is changed again and the deformation analysis is repeated, so that FIG. As shown in (c), it was possible to obtain a satisfactory material shape without forming defects.

[Comparison of simulation results]
FIGS. 8A and 8B are explanatory diagrams showing the deformation analysis model according to the first embodiment and its simulation results, and FIGS. 9A and 9B show the deformation analysis model according to the comparative example and its simulation results. It is explanatory drawing which shows a simulation result.

  The deformation analysis model of the first embodiment shown in FIG. 8 (a) reduces the calculation load by using the rigid molds 61 and 62 as a molding die, whereas the deformation analysis model of the comparative example shown in FIG. 9 (a). In the deformation analysis model, the mold is used as solid element models 61 ′ and 62 ′ to improve accuracy. However, in the deformation analysis model of the first embodiment shown in FIG. 8A, the rigid surface model of the mold is coordinate-converted according to the linear expansion coefficient, and the presence / absence of the air pocket 63 is separately determined. As shown in FIG. 8B and FIG. 9B, a simulation result with substantially the same accuracy as that of the comparative example in which the mold is a solid element model can be obtained.

  In the first embodiment, the force acting between the mold that is the deformation analysis model and the material, that is, the presence or absence of air accumulation is determined based on the coordinate of the material and the contact pressure (MPa). However, the present invention is not limited to this, and it is possible to determine the presence or absence of air clogging by other methods as long as it is possible to detect that transfer from the center of the molding surface to the material of the molding surface of the mold is not continuously obtained. is there.

  For example, in step S8 of the first embodiment described above, coordinate data for each node of the material in the deformation analysis process is output. Then, in step S9, compare whether the coordinate data is located on the same coordinate as the deformed rigid surface of the mold or on a line connecting the coordinates of the two rigid surfaces of the mold close to the material node. did.

  From this result, it was confirmed that air clogging occurs when the coordinates of the nodes located outside before the nodes located inside the material are located on the rigid surface of the mold. In this way, it is also possible to determine the presence or absence of air accumulation based on the position of the node of the material.

  As a method of confirming whether the outline coordinates of the material are located on the rigid surface of the mold, the coordinates of the rigid surface of the mold are approximated by an aspherical expression, etc., and the distance between the curve and the outline node of the material is calculated. Calculation may be made based on whether the distance is 0 (mm) or not.

  Next, a second embodiment of the present invention will be described with reference to FIGS. 10 (a) and 10 (b). 10A and 10B are explanatory views showing a deformation analysis model according to the second embodiment and a simulation result thereof.

In the second embodiment, the physical property values necessary for the material and the mold are prepared for constructing the deformation analysis model with the same molding machine and the same lens shape as the first embodiment. The material has an elastic modulus of 89.1 (GPa) and a Poisson's ratio of 0.247, and the linear expansion coefficient is 8.8 × 10 ⁻⁶ (/ K), which is the physical property value of the material. A value 3.9 × 10 ⁻⁶ (/ K) obtained by subtracting 4.9 × 10 ⁻⁶ (/ K) used for the linear expansion coefficient was used. The molding die used as a reference does not have a linear expansion coefficient because the shape is defined as designed.

  Modeling similar to that of the first example was performed using the physical property values (see FIG. 10A), and a press molding simulation was performed. In the deformation analysis process, the same air clogging as in the first embodiment was determined. As a result, the nodes located outside the nodes located inside (center side) of the material had contact pressure (MPa). The occurrence of air pockets was confirmed (see FIG. 10B). Therefore, we were able to obtain a satisfactory material shape by changing the shape of the material and repeating the deformation analysis and the determination of air accumulation again.

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a perspective view of an actual mold and material. FIG. 12 is an explanatory view showing a deformation analysis model of the mold and the material according to the third embodiment. FIG. 13 is an explanatory diagram showing a deformation analysis model of a mold and a material according to a comparative example.

  In FIG. 11, in the third embodiment, in the same molding machine as the first embodiment described above, the structure is changed so that the plane inserts 71 and 72 can be installed at an angle of 90 degrees on the lower shaft, and the cylinder Triangular prism molding using a shaped material 74 was modeled. The lower mold configuration is a configuration in which a tilt adjustment structure between the angle adjusting portion of the two planar inserts 71 and 72 and the upper mold 73 is provided. In the third embodiment, since the shape of the molded product is not rotationally symmetric, the deformation analysis model is a three-dimensional model as shown in FIG. In the figure, reference numerals 81 to 83 are rigid surface models of the mold, and reference numeral 84 is a solid element model of the material.

  Necessary material properties in the third embodiment are the same as those in the first embodiment. The creation of the shape model used for the deformation analysis model will be described in detail. In the third embodiment, the mold and the material are modeled as a material model that is thermally deformed. The shapes of the mold and the material at that time are modeled as designed, and the arrangement of the mold and the material is as shown in FIG. 11, which is an initial placement state at the time of actual molding.

  Using such a deformation analysis model, a deformation analysis is performed by expanding the molding temperature T from room temperature 25 (° C.) to 600 (° C.). From this result, when the material is deformed as the coordinates of the molding die, the molding die Only the molding surface including the part that is considered to contact the surface is selected, and the coordinates of the outer periphery of the material are output as the coordinates of the material. Then, the coordinates output as the coordinates of the mold are defined as a rigid surface model, and the coordinates of the material when thermally deformed are defined as a solid element model.

  Next, in the deformation analysis model created as described above, a press forming simulation in which the forming temperature 600 (° C.) is uniformly given to the entire material and the press load is 1000 (N) is shown in FIG. Performed in the same manner as S10. In addition, general-purpose finite element method analysis software ABAQUS / Standard was used for the simulation.

  In the third embodiment, in the deformation analysis process, the contact pressure generated between the mold and the material is displayed using ABAQUS / CAE. As a result, the analyst visually confirmed that the contact pressure of the node existing outside the node existing inside the material on one molding surface does not become larger than 0 (MPa), and the shape of the material As a result, no air accumulation occurred.

  Here, FIG. 13 is an explanatory view showing a deformation analysis model of a mold and a material according to a comparative example, and FIG. 14 is an explanatory view showing a state in which simulation results of the third embodiment and the comparative example are overlapped. .

  The deformation analysis model of the third embodiment shown in FIG. 12 uses a molding die as a rigid surface model to reduce the calculation load, whereas the deformation analysis model of the comparative example shown in FIG. The accuracy is improved as an element model. However, in the deformation analysis model of the third embodiment shown in FIG. 13, the rigid surface models 81, 82, 83 of the mold are coordinate-transformed according to the linear expansion coefficient, and the presence / absence of air pockets is separately determined. As shown in FIG. 14, a simulation result with almost the same accuracy as that of the comparative example in which the forming die is the solid element model 81 ′, 82 ′, 83 ′ can be obtained.

  According to the press molding simulation apparatus, the press molding simulation method, and the program for the optical element according to the present embodiment and each example, both the molding die and the material are thermally deformed according to the linear expansion coefficient, and the molding die By forming a rigid surface model with a value obtained by thermally deforming the sheet, it becomes possible to perform a press forming simulation in accordance with an actual phenomenon, and a simulation result with sufficiently practical accuracy can be obtained with a model having a small calculation scale.

  Also, either the mold or the material is defined as the design value, and the difference between the linear expansion coefficient of one member is defined as the other member based on the linear expansion coefficient of the member defined as designed. It is possible to ensure sufficient accuracy even in the press molding simulation that predicts the molding process in consideration of thermal deformation, given as the coefficient of linear expansion of the member, and if thermal deformation of only one member is considered Since it is good, a result similar to the filling condition in an actual mold can be obtained with a simple and small-scale model.

  Furthermore, in an axially symmetric molded product and a molded product having a large dimension in either the axial direction or the radial direction, sufficient accuracy can be secured by thermally deforming only each direction, or non-axisymmetric In a molded product and a molded product having a large dimension in a direction synthesized in one direction or two directions of an orthogonal coordinate system, sufficient accuracy can be secured by thermally deforming only each direction.

  In addition to this, in the process of deformation analysis, based on the force acting between the mold and the raw material, or the position information of the outer shape of the raw material, a molding defect whose transfer is not continuously obtained from the center of the molding surface, That is, it is possible to easily determine the air pool, and it is possible to improve the reliability of the simulation result without increasing the calculation scale.

In addition, the press molding simulation apparatus, the press molding simulation method, and the program of the present invention are not limited to the above-described embodiment and each example.
For example, in each of the embodiments described above, the linear expansion coefficient described in the catalog was used as the linear expansion coefficient of the mold and the raw material. However, experimentally measured values, values adjusted for the press molding simulation, and the like were used. Also good. Further, regarding the linear expansion coefficient having temperature dependence, it is still desirable to consider the dependence.

  In each of the above-described embodiments, the material is modeled as an elastic body, but a material model such as a viscoelastic body, a plastic body, or a superelastic body may be used in addition to the elastic body. In addition, it is desirable that the thermal deformation due to the heating of the material includes a step of raising the temperature in the press molding simulation and consider the thermal deformation of the preform according to the applied linear expansion coefficient. Furthermore, when the temperature of the material is not uniform, it is desirable to provide the temperature distribution.

  In each of the embodiments described above, ABAQUS / Standard, a general-purpose finite element method analysis program, is used for the simulation, but other finite element method analysis programs may be used instead of the above software. Also, the method of determining molding defects may be determined by a program that automatically outputs numerical values as shown in the embodiments and automatically determines molding defects in each calculation process.

  In each of the above-described examples, the glass blank press forming process is exemplified as the material. However, the scope of the present invention is not limited to glass press forming, but resin press forming, thermoplastic resin, glass and resin, Any processing method in which pressure is applied to the mold when the material and mold are heated and the mold shape is transferred to the material and molded, such as molding of organic-inorganic hybrid materials with the characteristics of metal and metal forging. In this case, the present invention can be applied.

  In addition, the mold can be applied to a mold made of a metal material such as cemented carbide including powder metallurgy or stainless steel, a mold made of ceramic material typified by glass or SiC, and the like. With respect to the method of installing the mold, there are vertical and horizontal molds depending on the molding machine, but in any case, the present invention can be applied. Furthermore, the present invention is not limited to the number of molds and the number of components around the mold.

It is a principle block diagram of the press molding simulation apparatus which concerns on this embodiment. It is a hardware block diagram of this press molding simulation apparatus. It is a fragmentary sectional view which shows the molding machine used for manufacture of the actual optical element in a 1st Example. It is a fragmentary sectional view of the radial direction bordering on the rotating shaft of the actual shaping | molding die and raw material in a 1st Example. It is a flowchart which shows the operation | movement procedure thru | or processing content of the press molding simulation method and program concerning a 1st Example. It is explanatory drawing which shows the deformation | transformation analysis model of the shaping | molding die shown in FIG. 4, and a raw material. (A), (b), and (c) are explanatory diagrams showing the process from the start to the end of the deformation analysis model. FIGS. 9A and 9B are explanatory views showing a deformation analysis model according to the first embodiment and a simulation result thereof. FIGS. 7A and 7B are explanatory diagrams showing a deformation analysis model according to a comparative example with respect to the first embodiment and a simulation result thereof. FIGS. 9A and 9B are explanatory diagrams showing a deformation analysis model according to the second embodiment and a simulation result thereof. It is a perspective view of the actual shaping | molding die and raw material in a 3rd Example. It is explanatory drawing which shows the shaping | molding die concerning this 3rd Example, and the deformation | transformation analysis model of a raw material. It is explanatory drawing which shows the deformation | transformation analysis model of the shaping | molding die and raw material which concern on the comparative example with respect to this 3rd Example. It is explanatory drawing which shows the state which accumulated the simulation result of the 3rd Example and the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Press molding simulation apparatus 11 Memory | storage means 12 Analytical model creation means 13 Expansion conversion means 14 Deformation analysis means 15 Press time measurement means 16 Air accumulation determination means 21 CPU
22 ROM
23 RAM
24 HDD
25 Operation Input Unit 26 Input / Output Device 27 Display Device 55 Air Puddle

Claims (12)

In a press molding simulation device that predicts the shape of a molded product obtained by heating and molding a mold and a material,
The mold is a rigid surface model, the material is a solid element model, and the mold and / or the material as the deformation analysis model is thermally deformed according to the respective linear expansion coefficient to perform simulation. Press molding simulation device.   When the shape of the molded product is axisymmetric, the simulation is performed by thermally deforming only one of the radial direction and the axial direction of the mold and / or the material according to the respective linear expansion coefficient. The press molding simulation apparatus for an optical element according to claim 1.   When the shape of the molded product is non-axisymmetric, only one of the X, Y, and Z directions in the orthogonal coordinate system of the molding die and / or material is thermally deformed according to the respective linear expansion coefficient for simulation. The press molding simulation device according to claim 1, wherein the press molding simulation device is performed.   When the shape of the molded product is non-axisymmetric, simulation is performed by thermally deforming any two directions of the X, Y, and Z directions in the orthogonal coordinate system of the molding die and / or material according to the respective linear expansion coefficients. The press molding simulation apparatus according to claim 1.   The difference between the linear expansion coefficients of the mold and the material is taken as the linear expansion coefficient of either of the mold or the material, and either the mold or the material is thermally deformed according to the linear expansion coefficient for simulation. 5. The press molding simulation apparatus according to claim 1, 2, 3 or 4, wherein: In a press molding simulation device that predicts the shape of a molded product obtained by heating and molding a mold and a material,
The deformation analysis is performed using the mold and the material as a deformation analysis model, and the molding failure in which the transfer to the material of the mold is not continuously performed from the inside to the outside is performed in the calculation result of the deformation analysis process. A press forming simulation apparatus characterized by determining based on the above.   The press molding simulation apparatus according to claim 6, wherein the molding failure is determined based on a force acting between the mold and a material in a deformation analysis process.   The press molding simulation apparatus according to claim 6, wherein the molding failure is determined based on position information of an outer shape of the material in a deformation analysis process. In a press molding simulation method for predicting the shape of a molded product obtained by heating and molding a mold and a material,
The mold is a rigid surface model, the material is a solid element model, and the mold and / or the material as the deformation analysis model is thermally deformed according to the respective linear expansion coefficient to perform simulation. Press molding simulation method. In a press molding simulation method for predicting the shape of a molded product obtained by heating and molding a mold and a material,
The deformation analysis is performed using the mold and the material as a deformation analysis model, and the molding failure in which the transfer to the material of the mold is not continuously performed from the inside to the outside is performed in the calculation result of the deformation analysis process. A press molding simulation method characterized by making a determination based on the above. In a program for causing a computer to execute a press molding simulation for predicting the shape of a molded product obtained by heating and molding a mold and a material,
The mold is a rigid surface model, the material is a solid element model, and the mold and / or material as a deformation analysis model is thermally deformed according to the respective linear expansion coefficient to perform a simulation. A program characterized by being executed by a computer. In a program for causing a computer to execute press molding simulation for predicting the shape of a molded product obtained by heating and molding a mold and a material,
The deformation analysis is performed using the mold and the material as a deformation analysis model, and the molding failure in which the transfer to the material of the mold is not continuously performed from the inside to the outside is performed in the calculation result of the deformation analysis process. A program for causing a computer to execute a process of making a determination based on a program.