JP2004025457A - Injection molding simulation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding simulation method capable of performing a highly precise simulation in view of mold deformation, while shortening the time for analyzing the resin pressure in particular. <P>SOLUTION: The injection molding simulation method 10, which successively performs filling analysis, pressure holding/cooling analysis and molding warping deformation analysis, detects the timing with a maximum clamping force detecting section 18 when the maximum clamping force is reached during filling time and pressure holding time from the start of filling resin into the mold to start analyzing the resin pressure within the mold with an analyzing section 14, on the basis of the timing to attain the maximum clamping force in view of the mold deformation. This enables analysis at an appropriate timing considering the mold deformation to perform highly precise analysis, while drastically reducing the load of the analysis calculation for shortening the processing time required for the entire simulation. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an injection molding simulation method, and more particularly to an improvement in a simulation method capable of shortening the simulation time while maintaining the accuracy of the simulation.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, when performing injection molding, simulation is performed in advance to analyze the behavior of a resin in a mold (mold) and the state of a molded product at the time of injection molding. Conventional injection molding simulations are performed by analysis using the finite element method or the like. In the analysis, the thickness (plate thickness) of the molded product does not change during molding, that is, the mold does not deform. It was done on the assumption. However, in practice, as shown in FIG. 9, when the mold is filled with resin or during the subsequent pressure holding, the inner wall surface of the mold is bent by receiving the resin pressure (the middle diagram in FIG. 9). Thereafter, when the resin is cooled and shrunk and the pressure is reduced, the bent mold starts elastic recovery, and a phenomenon occurs in which the pressure due to the elastic recovery force is applied to the resin side, that is, the molded product side. (Right figure in FIG. 9). Therefore, although the mold deformation is a large pressure change factor, since the mold deformation is not considered in the simulation, it has been difficult to say that the conventional simulation is performed with high accuracy.
[0003]
Therefore, an injection molding simulation method considering the elastic recovery force due to the mold deformation is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-269961. According to this simulation, in addition to the normal injection molding simulation, a simulation taking into account the deformation of the mold is performed, so that a simulation close to the actual pressure behavior can be performed.
[0004]
[Problems to be solved by the invention]
However, in the method disclosed in Japanese Patent Application Laid-Open No. 2001-269961, since the mold deformation simulation is performed for all the processes from the start of the injection molding, there is a problem that the total calculation time becomes very long. . Further, since the normal injection molding simulation and the mold deformation simulation are set as one set and the simulation is repeated for each time step and for each element, the calculation load increases and the calculation time further increases. Have been. Although it depends on the size of the molded article to be simulated, a large one such as an automobile bumper may take several weeks to several months, and there is a problem that the analysis efficiency is extremely low.
[0005]
The present invention has been made in view of the above problems, and provides a high-accuracy simulation in consideration of mold deformation, particularly a simulation method capable of shortening the simulation time while maintaining the simulation accuracy. Aim.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is an injection molding simulation method for sequentially performing a filling analysis, a holding pressure cooling analysis, and a molding warpage deformation analysis. A timing at which the mold clamping force becomes maximum within a time is detected, and an analysis of the resin pressure in the mold in consideration of the mold deformation is started from the maximum timing.
[0007]
Here, the mold clamping force is a force for clamping the opposing molds, and is necessary because when the molten resin is injected into the cavity under high pressure, the mold is not pushed open by the pressure of the resin. Force and can be obtained by the product of the projected area of the molded product and the resin pressure in the mold. Therefore, the point at which the mold clamping force becomes maximum can be regarded as the state in which the mold is deformed to the maximum. At this time, since the resin is applying pressure to the mold until the mold reaches the maximum deformation, the resin pressure in the mold can be easily obtained from the linear displacement data of the mold or the injection pressure data of the resin. be able to. Therefore, after the mold reaches the maximum deformation, it is a portion where the pressure is exerted on the resin due to the elastic recovery of the mold, and an analysis there is necessary.
[0008]
According to this configuration, since the pressure analysis considering the mold deformation is started from the point where the pressure effect due to the elastic deformation of the mold occurs, it is possible to perform the analysis considering the mold deformation at an appropriate timing. As a result, the load of the analysis operation can be significantly reduced, so that the processing time of the entire simulation can be reduced while performing a highly accurate simulation.
[0009]
In order to achieve the above object, the present invention provides the above-described configuration, wherein after the mold clamping force is maximized, the resin in the mold based on a time series change in the thickness of a molded product due to elastic recovery of the mold. It is characterized by performing pressure analysis.
[0010]
According to this configuration, by acquiring the time-series change of the plate thickness after the mold clamping force becomes maximum, the analysis of the resin pressure in the mold in the necessary portion is efficiently performed, so that the processing time of the entire simulation is reduced. Shortening can be performed.
[0011]
Further, in order to achieve the object as described above, in the above configuration, after the mold clamping force is maximized, the mold structural analysis is performed at each time step to calculate the amount of deformation of the mold. In addition, the resin pressure in the mold is analyzed by PVT resin characteristic analysis taking into account the change in the volume of the resin based on the deformation amount.
[0012]
According to this configuration, since the structure analysis is applied at the appropriate timing in the related art, the load of the pressure analysis calculation can be efficiently reduced, and a quick simulation can be performed.
[0013]
In addition, in order to achieve the above object, in the above configuration, in the above configuration, after the mold clamping force is maximized, a deformation amount of the mold for each time step is obtained from a model prepared in advance. Estimate based on the matrix table showing the relationship between the mold thickness and the pressure to deflect the mold, correct the resin pressure obtained by PVT resin characteristic analysis taking into account the volume change of the resin based on the estimated amount of deformation, and mold It is characterized in that the internal resin pressure is analyzed.
[0014]
In addition, in order to achieve the above object, in the above configuration, in the above configuration, after the mold clamping force is maximized, a deformation amount of the mold for each time step is obtained from a model prepared in advance. Estimate based on the regression equation showing the relationship between the mold thickness and the pressure to deflect the mold, correct the resin pressure obtained by PVT resin characteristic analysis taking into account the volume change of the resin based on the estimated amount of deformation, and mold It is characterized in that the internal resin pressure is analyzed.
[0015]
Here, the matrix table or the regression equation showing the relationship between the mold thickness obtained from the model prepared in advance and the pressure to deflect the mold means an experimental value or an analytical statistical method for a simple structure (for example, a multiple regression analysis). For various types of molds, it is possible to prepare mold materials with different material properties (eg, Young's modulus, Poisson's ratio, etc.) and mold sizes (large, medium, small, etc.). desirable.
[0016]
According to this configuration, it is possible to easily and quickly perform a pressure analysis after the mold clamping force is maximized using a matrix table or a regression equation, and take into account the deformation of the mold and perform the entire simulation. Can be shortened.
[0017]
Further, in order to achieve the above object, the present invention provides the above-mentioned configuration, wherein after the mold clamping force is maximized, the amount of deformation of the mold at each time step is determined by the thickness of the previously prepared mold. Estimating based on the actual measurement data of the deflection in the direction, correcting the resin pressure obtained by the PVT resin characteristic analysis in consideration of the volume change of the resin based on the estimated deformation amount, and analyzing the resin pressure in the mold. Features.
[0018]
Here, the actual measurement data is obtained by installing a sensor or the like on an actual model or a simplified model.
[0019]
According to this configuration, high-precision pressure analysis after the mold clamping force becomes maximum can be performed easily and quickly while taking into account the deformation of the mold, and the processing time of the entire simulation can be reduced. It can be carried out.
[0020]
In addition, in order to achieve the above object, the present invention is characterized in that, in the above-described configuration, a molding warpage deformation analysis is performed by further using an analysis result using the calculated pressure as an input condition.
[0021]
According to this configuration, a simulation including a molding warpage deformation analysis can be performed in a short time.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention (hereinafter, referred to as embodiments) will be described with reference to the drawings.
[0023]
The simulation in the injection molding includes the boundary of the resin viscosity, PVT characteristics, specific heat, physical properties such as thermal conductivity, the mold (die) used for injection molding to be subjected to element division, product shape, injection molding conditions, and the like. Calculation of resin properties such as temperature, pressure, orientation, shrinkage, and warpage is performed using conditions and constituent equations such as a motion equation, a continuity equation, and an energy equation. The analysis is usually a filling analysis to analyze the inflow of resin, a packing and cooling analysis to analyze the packing process to compensate for the shrinkage of the resin in the mold after filling, and a cooling process afterwards, and the product warpage after molding. It consists of a warpage deformation analysis for analyzing deformation.
[0024]
By the way, in injection molding, a cavity for receiving the molten resin is formed by combining a plurality of divided molds, but opposing molds are formed so that the molten resin injected during the injection molding does not leak. Need to be combined without gaps. Therefore, the dies must be pressed against each other so as to maintain a clamping force greater than the product of the resin pressure in the mold (average pressure in the mold) and the molding area (projected area) of the molded product. .
[0025]
FIG. 1 shows an example of a change in the mold clamping force during the injection molding process, that is, the filling time, the dwell time, and the cooling time of the resin.
[0026]
Normally, the resin is injected into the mold cavity at a high pressure, but the resin pressure in the mold increases due to an increase in flow resistance and a filling amount due to a change in the viscosity of the molten resin. Thereafter, when a predetermined amount of resin is injected into the cavity, the filling process ends. However, the resin filled in the cavity may shrink when cooled and solidified, causing "sink". Therefore, a predetermined pressure is applied to the resin even after the predetermined amount of the resin is filled, and the resin for the shrinkage is further added to suppress the sink of the molded product. That is, the injection pressure of the resin is maintained for a predetermined time. This time corresponds to the dwell time.
[0027]
In the resin filling stage and the dwelling stage, since the resin in a high pressure state exists in the cavity, the mold is bent by the resin pressure. Thereafter, the resin in the cavity is gradually cooled and starts shrinking. If there is no bending of the mold due to the resin pressure as described above, the pressure in the mold will decrease sharply when the resin begins to cool and shrink, but in reality there is elastic recovery of the mold, so the mold side is closer to the resin side. To apply pressure. The pressure based on the elastic recovery of the mold is one of the causes of the pressure fluctuation phenomenon on the resin during the simulation. As described above, the analysis considering the deformation of the mold has a large computational load. Therefore, the point at which the pressure analysis in consideration of the deformation of the mold is performed is a point of improving the efficiency of the analysis.
[0028]
The characteristic feature of the present embodiment is to reduce the time of the entire simulation by detecting the timing at which the mold clamping force becomes maximum and starting the analysis of the resin pressure in the mold in consideration of the mold deformation from the maximum timing. By the way.
[0029]
In other words, in the range where the mold undergoes linear deformation under the pressure from the resin, the injection pressure of the resin governs the resin pressure in the mold, so the pressure analysis of this part can be grasped with higher accuracy than before. it can. Therefore, if the behavior from the time when the mold starts to recover elastically is obtained, the analysis of the actual resin pressure in the mold can be accurately grasped as a whole.
[0030]
FIG. 2 is a functional block diagram illustrating an example of a simulation device 10 including a computer or the like that executes an injection molding simulation according to the present embodiment. The simulation apparatus 10 according to the present embodiment includes an input unit 12 for inputting various condition data, an analysis unit 14 for performing various analyzes based on the input data, and an output unit 16 such as a display or a printer for outputting an analysis result. In addition, a portion that performs processing of the features in the present embodiment, for example, a maximum mold clamping force detecting unit 18 that detects a timing at which the mold clamping force becomes maximum, A displacement calculating unit 20 that calculates the amount of displacement (bending amount) of the mold from the generation timing, and a database (a matrix table and measured data to be described later) used as needed when calculating the amount of bending (bending amount) of the mold. 22). In the present embodiment, the analysis processing itself is used while appropriately selecting a well-known analysis method such as a finite element method. FIG. 2 for explaining the simulation apparatus 10 according to the present embodiment is shown in a functional block diagram for clarifying the function of the simulation apparatus 10, but, of course, the maximum mold clamping force detection unit 18 and the displacement calculation unit The function 20 can be realized by software, and the simulation apparatus 10 may perform the processing in a CPU including the analysis unit 14 and the like. In the present embodiment, the molded article to be simulated is, for example, an automobile bumper.
[0031]
FIG. 3 is a flowchart illustrating a procedure of the injection molding simulation according to the present embodiment.
[0032]
First, when starting the simulation, the simulation apparatus 10 inputs basic data on injection molding via the input unit 12 (S100). Here, for example, data necessary for the simulation, such as molding conditions, physical conditions of the mold and the resin, and the like are input as appropriate. When acquiring the necessary data, the simulation apparatus 10 starts the filling / holding pressure analysis by the analysis unit 14 (S101). In the filling analysis, the start of the resin injection is set to time “0”, and the resin flowing pattern when the molten resin is injected into the cavity is analyzed. Here, the resin is injected in an amount determined in advance for each molded product.
[0033]
When the filling of the predetermined amount of resin is completed, the analysis unit 14 starts the pressure-holding analysis, and analyzes the state in which the pressure propagation by the resin spreads over the entire mold. While the conventional general filling / holding pressure analysis is performed by the analyzing unit 14, the maximum mold clamping force detecting unit 18 performs a process of detecting the maximum mold clamping force during the filling time and the holding pressure time. The simulation device 10 divides a molded product (for example, a bumper) in a mold cavity into elements (for example, a mesh of 10 mm × 10 mm), and applies a pressure acting on each element, a projected area of the element in the mold opening / closing direction, and the like. , And the sum of the calculated values of all the elements is calculated to determine the force acting on the mold at an arbitrary time step (an arbitrary time step that can be arbitrarily set according to a simulation). (S102). The calculated mold clamping force at an arbitrary time step is compared with the mold clamping force calculated at the previous time step (S103), and the mold clamping force at the current time step is larger than the mold clamping force at the previous time step. If so, the mold clamping force is overwritten and stored in the memory (S104). At the time of calculating the first mold clamping force, since there is no previous data, the first mold clamping force is stored in the memory as it is. In the comparison in (S103), when the mold clamping force in the current time step is smaller than the mold clamping force in the previous time step, the process returns to (S102), and the mold clamping force is calculated again in the next time step. Subsequently, the simulation device 10 determines whether or not the preset dwell time has ended (S105). The pressure holding time varies depending on the molding conditions and the molded product, but is, for example, several seconds to several tens of seconds. If the dwell time has not elapsed, the process returns to (S102), and the process of calculating the mold clamping force again and comparing it with the previously calculated value is repeated as described above. That is, by the processes of (S102) to (S105), the maximum mold clamping force after the start of filling (filling time and pressure holding time) is stored in the memory. Since the supply of the injection pressure is stopped after the end of the dwell time, there is no need to perform the process of detecting the maximum mold clamping force after the end of the dwell time. If the simulation device 10 determines that the preset dwell time has ended, it ends the filling and dwell analysis process in the mold (S106).
[0034]
Subsequently, the simulation device 10 generates the maximum mold clamping force generation timing t stored in the memory._sIs extracted (S107). That is, the timing at which the influence of the pressure due to the elastic recovery of the mold, which is a feature of the present embodiment, starts to be considered is extracted. Then, the simulation device 10 calculates the time t of each element by the displacement calculating unit 20._sT, which is affected by the elastic recovery of the mold, based on_{s + i}(T_sThen, the displacement amount in the direction of the plate thickness (thickness of the molded product) at the time after i time step is calculated (S108). Here, i indicates the lapse of a time step, and i = i₀+1 and i₀= -1, 0, 1, 2,... Here, time t_{s + i}The thickness of the molded product can be calculated by, for example, a method based on a conventional mold structure analysis.
[0035]
Then, the analyzing unit 14 calculates the time t_{s + i}(S109) Specifically, the change in the thickness is determined by the volume V of the cavity of the mold._{s + i}(T_sTo each element volume after i time step), and the pressure P corresponding to the changed volume_{s + i}(T_sIs calculated based on the PVT resin characteristic analysis (analysis based on the relationship between pressure, volume, and temperature). At this time, time t_{s + i}Pressure P_{s + i}, Temperature T_{s + i}(T_sTo the resin temperature after the i-hour step), the plate thickness th_{s + i}(T_s, The sheet thickness after i time step), the sheet thickness correction value is th_{s + i}= Th₀+ Δ (t_{s + i}). And the element volume correction value is V_{s + i}= S × th_{s + i}Pressure correction value P_{s + i}Is V_{s + i}And T_{s + i}Can be obtained by substituting into the relational expression of PVT. Where t_sIs the time at the maximum clamping force, th₀Is the thickness of each element when the mold is not deformed, δ (t_{s + i}) Is t_sAnd i is the displacement amount of each element in the plate thickness direction after i time steps. Note that the first correction processing, that is, when i = 0 (t_s) Is a volume correction only, not a pressure correction.
[0036]
Correction pressure P for each element_{s + i}Is calculated, the simulation device 10 stores the pressure corrected for each element in the memory (S110), and reflects the pressure in the pressure analysis at the time of the filling analysis and the pressure-holding analysis. Further, a molding warpage deformation analysis is performed using the analysis result using the corrected (calculated) pressure as an input condition. That is, the residual stress of the resin is calculated based on the corrected pressure and the like, the structural analysis is performed based on the residual stress and the shape of the product (molded product), and the molding warpage deformation analysis of the molded product is performed. Thereafter, it is determined whether or not the preset cooling time has ended (S111). If the cooling time has not ended yet, the process returns to (S108), and the sheet thickness direction of the next time step is determined. The amount of displacement is calculated, and the pressure is corrected based on the time-varying thickness, and is reflected in the analysis. On the other hand, when it is determined that the cooling time has ended, the analysis processing is ended (S112), and the result is output to the output unit 16 as necessary, and the entire simulation is ended.
[0037]
As described above, the timing t at which the mold clamping force is maximized_sBy performing the analysis including the pressure correction in consideration of the elastic recovery of the mold only thereafter, the simulation processing is reduced, and the overall processing time can be reduced.
[0038]
By the way, the method shown in the flowchart of FIG. 3 can significantly reduce the entire processing time by limiting the analysis relating to pressure to a specific range as compared with the conventional simulation. Since the analysis of the structure of the mold is used, the processing time necessarily increases as the size of the molded product increases. Therefore, FIG. 4 shows a simple method of performing a simulation analysis approximately without using a structural analysis of a mold. Even in this simple method, the elastic recovery of the mold is taken into consideration because the timing (t) at which the mold clamping force becomes maximum within the filling time and the holding pressure time after the resin filling into the mold is started._s), And the processing up to the calculation of the maximum mold clamping force is the same as (S100) to (S107) in the flowchart of FIG. 3, and the illustration and description in the flowchart of FIG. 4 are omitted.
[0039]
In the flowchart of FIG. 4, when the maximum mold clamping force is calculated, the time t_{s + i}(T_sThen, the amount of bending of the mold at the time after i time step) is obtained (S200). Here, i indicates the lapse of a time step, and i = i₀+1 and i₀= -1, 0, 1, 2,... Here, the prediction of the amount of bending of the mold is performed not by performing the mold structure analysis every time as in the method shown in FIG. The relationship is shown in a matrix table as shown in FIG. 5, and by referring to the data, the analysis time is shortened while maintaining the analysis accuracy by performing the thickness correction. The matrix table is stored in the database 22.
[0040]
The factors in the matrix table shown in FIG. 5 are based on “die thickness” and “die bending force”, and mold material properties (for example, Young's modulus and Poisson's ratio) and die size (large , Medium size, small size, etc.). The force to bend the mold can be defined by the resin pressure in the mold × the projected area of the molded product.
[0041]
The mold model having a simple structure used at this time includes, for example, four members of a fixed die, a movable die, a fixed die plate, and a movable die plate as shown in FIG. 6A, and as shown in FIG. The amount of bending of the mold according to the thickness of the mold of the part to be actually analyzed can be selected from the matrix table. In addition, by considering the die plate as a factor of the matrix table, it is possible to improve the accuracy of predicting the amount of deflection when using a model having a simple structure. This is because, as shown in FIG. 6B, the bending of the mold extends not only to the fixed die and the movable die but also to the fixed die plate and the movable die plate. The prediction accuracy can be improved by setting the deflection amount in consideration of the above.
[0042]
As described above, the time t_{s + i}After obtaining the amount of deflection of the mold, the volume correction for each element (V_{s + i}Is calculated (S201), and V_{s + i}And T_{s + i}Is substituted into the relational expression of the PVT resin characteristic to obtain the corrected pressure P for each element._{s + i}Is calculated (S202). Correction pressure P for each element_{s + i}Is calculated, the simulation device 10 stores the corrected pressure for each element in the memory (S203), and reflects the pressure in the pressure analysis at the time of the filling analysis and the pressure-holding analysis. Further, a molding warpage deformation analysis is performed using the analysis result using the corrected (calculated) pressure as an input condition. That is, the residual stress of the resin is calculated based on the corrected pressure and the like, the structural analysis is performed based on the residual stress and the shape of the product (molded product), and the molding warpage deformation analysis of the molded product is performed. Thereafter, it is determined whether or not the preset cooling time has ended (S204). If the cooling time has not ended yet, the process returns to (S200) and the next time of the next time step is performed. The amount of deflection for each element of the step is calculated, the volume is corrected, then the pressure is corrected, and the result is reflected in the pressure analysis and the warpage analysis. On the other hand, if it is determined that the cooling time has ended, or if it is determined that the cooling time has ended, the analysis process is ended (S205), and the result is output to the output unit 16 as necessary, thereby ending the entire simulation. .
[0043]
As described above, the pressure analysis is further simplified by using the matrix table based on the simplified model prepared in advance without using the structural analysis for the deformation analysis of the mold, and the method shown in the flowchart of FIG. It is possible to increase efficiency, further reduce simulation processing, and significantly reduce the overall processing time.
[0044]
In the above example, the amount of deflection was obtained by referring to a prepared matrix table.However, a necessary numerical value was directly substituted into a regression equation obtained at a stage before the matrix table was created, and the amount of deflection was calculated. This also enables efficient deflection amount calculation. Note that the regression equation can be stored in the database 22, the displacement calculator 20, or the like.
[0045]
In the above-described example, a matrix table showing the relationship between the thickness of the mold and the pressure for bending the mold is created using a simple model, and the time t_{s + i}(T_sAlthough the example in which the deflection amount of the mold at the time after the i-th time step is obtained is shown, as shown in FIG. 7, as shown in FIG. Data) may be created in advance and used for acquiring the amount of deflection in (S200) of the flowchart of FIG. In this case, the related table indicating the amount of displacement in the thickness direction with time can be created based on an empirical curve using actual measurement values obtained by attaching a sensor or the like to a similar part. Of course, from the result of the simple configuration analysis using the simple mold model as described above, a related table indicating the displacement amount in the thickness direction due to the time change may be created. These related tables are also stored in the database 22.
[0046]
Further, the resin pressure calculated by the conventional injection molding analysis (analysis not considering the deformation of the mold) in each time step using the deflection amount of the mold obtained from the database as described above is corrected. Good. By performing such processing, it is possible to easily and easily perform a simulation at the time of injection molding in consideration of mold deformation with a light load, and it is possible to significantly reduce the simulation processing time.
[0047]
The matrix shown in FIG. 6 and the association table shown in FIG. 7 may be used independently for each simulation object, or used separately for each element, that is, for each part in the simulation of the same molded article. You may.
[0048]
FIG. 8 shows the analysis results of the pressure of each element in comparison with the actually measured values for reference. That is, it shows how the case where the deformation of the mold is not considered and the case where it is considered as in the present embodiment are different. In FIG. 8, a thick solid line indicates the measured pressure, a line indicated by ● indicates a simulated pressure obtained when the deformation of the mold is not considered, and a line indicated by ▲ indicates the case where the deformation of the mold is considered. Is the simulation pressure obtained. As is clear from FIG. 8, according to the present embodiment, it is possible to realize a very accurate simulation. Then, as described in the present embodiment, the pressure analysis is started by considering the mold deformation from the point where the pressure is affected by the elastic deformation of the mold, that is, from the timing when the mold clamping force is maximized. Simulation time can be significantly reduced.
[0049]
【The invention's effect】
According to the present invention, since the pressure analysis taking into account the mold deformation is started from the point where the pressure effect due to the elastic deformation of the mold occurs, that is, the timing at which the mold clamping force is maximized, the analysis taking into account the mold deformation at an appropriate timing Can be performed, and the load of the analysis operation can be significantly reduced. Therefore, the processing time of the simulation for performing the analysis with high accuracy can be easily reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an example of a change in a mold clamping force in an injection molding process.
FIG. 2 is a configuration block diagram of a simulation device that executes an injection molding simulation according to the embodiment of the present invention.
FIG. 3 is a flowchart illustrating a procedure of an injection molding simulation according to the embodiment of the present invention.
FIG. 4 is a flowchart illustrating another procedure of the injection molding simulation according to the embodiment of the present invention.
FIG. 5 is an example of a matrix table used in an injection molding simulation according to the embodiment of the present invention.
FIG. 6 is an explanatory diagram of a mold for explaining factors of a matrix table used in an injection molding simulation according to the embodiment of the present invention.
FIG. 7 is an example of a relation table used in an injection molding simulation according to the embodiment of the present invention.
FIG. 8 is an explanatory diagram showing a simulated pressure and a measured pressure in a case where mold deformation is not taken into consideration;
FIG. 9 is an explanatory diagram illustrating that a mold is deformed by injected resin.
[Explanation of symbols]
10 simulation device, 12 input unit, 14 analysis unit, 16 output unit, 18 maximum clamping force detection unit, 20 displacement calculation unit, 22 database.

Claims (7)

An injection molding simulation method for sequentially performing filling analysis, holding pressure cooling analysis, and molding warpage deformation analysis,
It is characterized by detecting the timing when the mold clamping force becomes maximum within the filling time and the dwelling time from the start of filling the resin into the mold, and starting the analysis of the resin pressure in the mold in consideration of the mold deformation from the maximum timing. Injection molding simulation method. The method of claim 1, wherein
An injection molding simulation method characterized in that after the mold clamping force becomes maximum, the resin pressure in the mold is analyzed based on a time-series change in the thickness of a molded product due to elastic recovery of the mold. The method of claim 1, wherein
After the mold clamping force becomes maximum, the mold structural analysis is performed at each time step to calculate the amount of deformation of the mold. An injection molding simulation method characterized by performing pressure analysis. The method of claim 1, wherein
After the mold clamping force is maximized, the amount of deformation of the mold at each time step is estimated based on a matrix table showing the relationship between the mold thickness and the pressure to deflect the mold obtained from a previously prepared model. An injection molding simulation method comprising correcting a resin pressure obtained by PVT resin characteristic analysis in consideration of a volume change of a resin based on an estimated deformation amount and analyzing a resin pressure in a mold. The method of claim 1, wherein
After the mold clamping force is maximized, the amount of deformation of the mold at each time step is estimated based on a regression equation showing the relationship between the mold thickness and the pressure to deflect the mold obtained from a previously prepared model, and An injection molding simulation method comprising correcting a resin pressure obtained by PVT resin characteristic analysis in consideration of a volume change of a resin based on an estimated deformation amount and analyzing a resin pressure in a mold. The method of claim 1, wherein
After the mold clamping force is maximized, the amount of deformation of the mold at each time step is estimated based on the measured data of the deflection in the thickness direction of the mold prepared in advance, and the resin is deformed based on the estimated amount of deformation. An injection molding simulation method, wherein a resin pressure obtained by a PVT resin characteristic analysis in consideration of a volume change is corrected and an in-mold resin pressure is analyzed. The method according to any one of claims 1 to 6, wherein
An injection molding simulation method characterized by performing a molding warpage deformation analysis by further using an analysis result using the calculated pressure as an input condition.

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