JP4765883B2 - Foam injection molded product quality prediction system, program, and method - Google Patents

Description

  The present invention relates to a technique for evaluating the surface quality of a foam injection molded article.

A foam injection molding method is known in which a raw material resin to which a foaming agent or gas is added is injection-molded to obtain a molded product that is a foam. Such a foam injection molding method is characterized in that a molded product having a good appearance and foamed only inside is obtained.
For example, the USM method, which is one of the foam injection molding methods, is a method in which a foaming agent or a gas-containing raw material resin is injected into a cavity in a mold, and then a part of the cavity is expanded and foamed. is there.

Conventionally, in injection molding, the quality of a molded product is predicted by simulation using a computer before actually producing a molding die and mounting the die on an injection molding machine to produce a resin molded product. Computer aided engineering (CAE) analysis techniques have been proposed. For example, Patent Document 1 proposes a method for predicting the quality of an injection molded product at the stage of simulation using a CAE analysis method.
In such a CAE analysis method, first, CAE is added by adding incidental conditions such as gates and runners to the molded product model data corresponding to the final resin molded product created by the computer aided design (CAD) system. Create a finite element model data of the molded product consisting of finite elements for analysis, and then perform CAE analysis to simulate the flow and solidification state of the molten metal in the mold in injection molding using the created finite element model data of the molded product. The mold shape and the molding conditions (such as the profile of temperature and pressure for setting in the injection molding machine) for determining the shape of the molded product are determined.

However, in the foam injection molding, unlike the injection molding as described above, since there is foaming by a foaming agent or gas in the molding process, the influence of this foaming is not considered in the same method as the injection molding. The surface quality of the molded product cannot be evaluated.
In other words, unlike injection molding, the molded product by foam injection molding may have surface irregularities due to foaming, which may impair quality. Also, unlike injection molding, foam injection molding has a rapid increase in resin volume due to foaming in the molding process, but due to restrictions on the shape of the mold, the degree of increase in volume varies depending on the part. This may cause the surface quality of the molded product to be impaired.
JP 10-138308 A

  Therefore, the present invention proposes a quality prediction method for a resin molded product in which the quality of a resin molded product molded by the foam injection molding method is predicted at the stage of simulation in CAE analysis.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, after the foamable resin is injected and filled in the cavity in the mold, the surface quality of the foamed injection molded product obtained by expanding a part of the cavity and foaming is predicted. In the quality prediction system, each physical quantity of the resin pressure at the completion of resin filling into the cavity, the resin temperature, the gas solubility in the resin, and the expansion amount of the resin when expanding a part of the cavity is used as at least variables. A regression equation is set to calculate the evaluation standard value of the surface quality of the molded product including the physical quantities obtained by the foam injection molding simulation between the first point and the second point on the surface of the molded product. An evaluation reference value calculation unit that calculates an evaluation reference value by substituting into the regression equation, and a determination unit that determines the quality of the surface quality of the molded product based on the evaluation reference value A.

  In claim 2, the quality for predicting the surface quality of the foamed injection-molded product obtained by injecting and filling the foamable resin into the cavity in the mold and then expanding and foaming a part of the cavity In the prediction system, CAD means for creating molded product finite element model data, CAE analysis means for performing foam injection molding simulation based on the molded product finite element model data, resin pressure when resin filling into the cavity is completed, and resin A regression equation is set to calculate the evaluation standard value of the surface quality of a molded product that includes at least each physical quantity as a variable, including the temperature, gas solubility in the resin, and the amount of expansion of the resin when a part of the cavity is expanded. The physical quantities obtained by the simulation between the first point and the second point on the surface of the molded product are substituted into the regression equation. An evaluation reference value calculating means for calculating an evaluation criterion value based on said evaluation criterion value, the judging means for judging quality of the surface quality of molded products, those provided.

  In Claim 3, said 2nd point is located in the upstream or downstream of the flow direction of a foamable resin rather than said 1st point.

  In Claim 4, the said determination means calculates the differential value of the said evaluation reference value, and when the said differential value exceeds the preset threshold value, it determines the surface quality defect of a foam injection molded product. is there.

  In claim 5, in order to predict the surface quality of a foam injection molded product obtained by injecting and filling a foamable resin into a cavity in a mold and then expanding a part of the cavity to foam. In addition, the surface of the molded article includes at least the physical quantities of the resin pressure, the resin temperature, the gas solubility in the resin, and the expansion amount when a part of the cavity is expanded, at the completion of resin filling into the cavity. The physical quantities obtained by the foam injection molding simulation between the first point and the second point on the surface of the molded product are acquired in a computer in which a regression equation for calculating the quality evaluation standard value is set in advance. Then, by substituting each acquired physical quantity into the regression equation, an evaluation reference value calculation process for calculating an evaluation reference value, and a determination process for determining the quality of the surface quality of the molded product based on the evaluation reference value. It is intended to execute and.

  In Claim 6, in the said determination process, when the differential value of the said evaluation reference value is calculated and the said differential value exceeds the preset threshold value, the defect of the surface quality of a foam injection molded product is determined. is there.

  In claim 7, comprising an evaluation reference value calculation means and a determination means, and after injecting and filling the foamable resin into the cavity in the mold, a part of the cavity is expanded and foamed. In the quality prediction system for predicting the surface quality of the foam injection molded product obtained in the above, the evaluation reference value calculation means uses the resin pressure at the completion of resin filling into the cavity, the resin temperature, the gas solubility in the resin, and the cavity. In the step of setting a regression equation for calculating the evaluation standard value of the surface quality of the molded product, including at least a variable as the amount of expansion when expanding a part of, and the evaluation standard value calculation means, A step of calculating an evaluation reference value by substituting each physical quantity obtained by the foam injection molding simulation between the first point and the second point on the surface of the molded product into the regression equation. When, in the determination unit, based on the evaluation reference value, and determining the quality of the surface quality of the molded article, those provided.

  According to an eighth aspect of the present invention, a CAD unit, a CAE analyzing unit, an evaluation reference value calculating unit, and a determining unit are provided. After the foamable resin is injected into the cavity in the mold and filled, In the quality prediction system for predicting the surface quality of the foam injection molded product obtained by expanding the part and foaming, the CAD means creates the molded product finite element model data, and the CAE analysis means Performing foam injection molding simulation based on the finite element model data of the molded product, and the resin pressure at the completion of the resin filling into the cavity, the resin temperature, and the gas solubility in the resin by the evaluation reference value calculating means And the amount of expansion when expanding a part of the cavity, calculate the evaluation standard value of the surface quality of the molded product, including at least each physical quantity as a variable. In the step of setting a regression equation, the physical quantity obtained by the simulation between the first point and the second point on the surface of the molded product in the evaluation reference value calculation means is converted into the regression equation. Substituting and calculating an evaluation reference value, and determining the quality of the surface quality of the molded product based on the evaluation reference value by the determination means.

  In Claim 9, said 2nd point is located in the upstream or downstream of the flow direction of raw material resin rather than said 1st point.

  In Claim 10, the said determination means calculates the differential value of the said evaluation reference value, and when the said differential value exceeds the preset threshold value, it determines the surface quality defect of a foam injection molded product. is there.

  As effects of the present invention, the following effects can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the surface quality (surface uneven | corrugated shape defect) of the resin molded product shape | molded by the foam injection molding method can be evaluated in the stage of the simulation in CAE analysis.

Next, embodiments of the invention will be described.
FIG. 1 is a flow chart of foam injection molding according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the structure of a foam injection molding machine, and FIG. 3 is a diagram showing a state of a mold during core back.
4 is a block diagram of a quality prediction system according to an embodiment of the present invention, FIG. 5 is a flow chart of quality prediction processing, FIG. 6 is a view showing a state of hot water flow in the cavity, and FIG. FIG. 8 is a diagram showing an example of an evaluation reference value in AA ′, FIG. 9 is a diagram showing an example of a judgment reference value in AA ′, and FIG. 10 is a judgment. FIG. 11 is a diagram for explaining another example of the reference value calculation method, and FIG. 11 is a diagram for explaining an example of the determination reference value output method.

  The present invention is a foam injection molding method in which a raw material resin to which a foaming agent or a gas is added (hereinafter referred to as “foamable resin”) is injected into a mold to obtain a molded product as a foam. In particular, the present invention relates to a technique for predicting the surface quality of a molded article, which is suitable for a method (USM method) in which a foamable resin is injected into a mold and then a part of the mold is expanded and foamed.

  For example, as shown in FIG. 2, the foam injection molding machine includes a mold 20 having a cavity 19 and an injection device 10 that injects a foamable resin into the cavity 19. The injection device 10 includes a cylinder 11 that holds the foamable resin introduced from the hopper 12 while being heated and melted, a screw 13 that extrudes the foamable resin in the cylinder 11, an injection cylinder 15 that drives the screw 13, and hydraulic pressure The motor 14 is configured.

The molding process using the foam injection molding machine having the general configuration as described above is, for example, as shown in FIG.
First, the mold 20 is clamped (S1), and the cavity 19 is formed inside the mold 20. Next, a foamable resin, which is a raw material resin to which a foaming agent such as carbon dioxide gas is added, is injected from the cylinder 11 into the cavity 19 through the nozzle and the runner 16 (S2). After the foamable resin is filled in the cavity 19, as shown in FIG. 3, the slide core 17 of the mold 20 is moved in a direction in which the mold 19 moves backward from the cavity 19 (S3). Thereby, a part of the cavity 19 is enlarged, the gas contained in the foamable resin is foamed and expanded, and the volume of the foamable resin (the thickness of the molded product) is increased.
Subsequently, after cooling for a predetermined time (S4), the mold 20 is released and the molded product is taken out from the mold 20 (S5).

Next, the quality prediction system 30 according to the embodiment of the present invention will be described.
FIG. 4 is a conceptual diagram showing the configuration of the quality prediction system 30 in foam injection molding.
The quality prediction system 30 includes a CAD device 32, a CAE analysis device 34, a quality prediction device 36, and the like each formed of an electronic computer (computer).

  Data can be transmitted from the CAD device 32 to the CAE analysis device 34 and from the CAE analysis device 34 to the quality prediction device 36. Note that the CAD device 32 and the CAE analysis device 34, and the CAE analysis device 34 and the quality prediction device 36 can be configured to transmit and receive information to and from each other via communication means, and information is recorded on a recording medium. Thus, information can be transmitted from one device to another device.

The CAD device 32 is a means for creating finite element model data of a molded product by a computer aided design technique.
The CAD device 32 has a function of designing (creating) a molded product model such as a solid model or a shell model based on a product, and mesh data which is finite element model data of the molded product based on the molded product model. A function to create is provided.
As the CAD device 32, a commercially available general CAD dedicated device or a general-purpose computer that is an electronic computer in which a CAD program is installed can be adopted.

The CAE analyzer 34 is a means for performing a foam injection molding simulation based on molded product finite element model data by a computer aided engineering technique.
The CAE analysis device 34 is a computer in which a foam injection molding CAE analysis program is installed in a general-purpose computer that is an electronic computer, and includes a storage unit in which the foam injection molding CAE analysis program and a database are stored. In the database of the CAE analysis device 34, accessory condition data of the mold, molding condition data, performance data, and the like are stored.
In addition, as the CAE analysis device 34, a dedicated device that performs foam injection molding simulation may be employed.

The CAE analyzer 34 gives a foaming injection molding simulation, which is a simulation of the flow of the foamable resin in the mold and the solidified state in the foam injection molding by giving molding conditions to the molded product finite element model data. The function to perform is provided.
In the present embodiment, the foaming resin flow pattern and the cavity 19 are filled with the foaming resin through the foaming injection molding simulation by the CAE analysis device 34 (hereinafter referred to as “when resin filling is completed”). The pressure of the foamable resin (resin pressure P), the temperature of the foamable resin (resin temperature T), the solubility of the gas for foaming the foamable resin in the resin (gas solubility C), and the like can be obtained.

  The quality prediction device 36 is an electronic computer such as a general-purpose computer, and by executing a quality prediction program on the electronic computer, an evaluation reference value calculation means, a determination means, and an evaluation reference value of the surface quality of the molded product It functions as a storage unit for regression equation for calculating R.

In addition, the quality prediction device 36 includes a storage unit in which the quality prediction program and the database are stored.
The database of the quality prediction device 36 includes the resin pressure P, the resin temperature T, the gas solubility C in the resin, and the expansion amount (core back amount L) when a part of the cavity is expanded. The regression equation for calculating the evaluation standard value R of the surface quality of the molded product including at least each physical quantity as a variable is preset and stored. Further, in the database of the quality prediction device 36, a threshold value q used for determining the quality of the surface quality of the molded product based on the determination reference value Q is set and stored in advance.
The “evaluation reference value R” and “determination reference value Q” will be described later.

The evaluation reference value calculation means means that each physical quantity (resin filling completed) obtained by foam injection molding simulation by the CAE analyzer 34 between the first point and the second point on the surface of the molded product. This is a means for calculating the evaluation reference value R by substituting the resin pressure P, the resin temperature T, the gas solubility C into the resin, and the core back amount L) into the regression equation.
Further, the determination means is a means for determining the quality of the surface quality of the molded product based on the evaluation reference value R. Specifically, the determination reference is an absolute value of a differential value of the evaluation reference value R. The value Q is calculated, and when the determination reference value Q exceeds the threshold value q, the surface quality defect of the molded product is determined.

  In the present embodiment, the CAD device 32, the CAE analysis device 34, and the quality prediction device 36 are configured as independent electronic computers (computers), but they are provided in one electronic computer. The quality prediction system 30 can also be configured with all functions.

  Next, the flow of quality prediction processing by the quality prediction system 30 will be described with reference to FIG.

In the quality prediction system 30, first, a CAD product 32 designs a molded product model corresponding to a molded product as a product (S21), and based on the molded product model, the molded product model data (molded product shape data). ) Is created (S22).
At this time, after the foamable resin is filled in the cavity 19, the movement amount when the slide core 17 of the mold 20 moves in the direction of retreating from the cavity 19, that is, the expansion amount of the foamable resin (core back amount L ) Is also calculated. It should be noted that the core back amount L differs depending on each part due to the shape of the mold even in the same mold.
The molded product model data is three-dimensional mesh data in the present embodiment, but may be shell data or the like. This molded product model data is transmitted to the CAE analyzer 34.

Next, in the CAE analyzer 34, the incidental conditions of the mold such as the gate and the runner are added to the molded product model data (S23).
The incidental conditions can be read out from those previously set in the CAE analyzer 34 or can be newly designed and set.

Then, analysis modeling is performed on the molded product model data to which the accessory condition data of the mold is added by the CAE analysis device 34, and analysis model data is created (S24).
In this case, the molded product model data with incidental conditions is automatically decomposed into three-dimensional finite elements, and analysis model data composed of finite elements for CAE analysis is created.

  Further, the CAE analyzer 34 supplies the analysis model data with specifications of the foamable resin such as mold temperature, foaming resin injection speed, temperature, viscosity, specific heat, gas pressure, and volume supplied from the database. Similarly, the performance data of the foam injection molding apparatus supplied from the database is added (S25) and the foam injection molding simulation (CAE analysis) is performed (S26).

  Through the foam injection molding simulation by the CAE analyzer 34, the flow pattern of the foamable tree is analyzed. For example, as shown in FIG. 6, the foamable resin has a flow pattern that flows from the gate 18 to the cavity 19 through the runner 16 and spreads around the gate 18. In FIG. 6, constant velocity lines of the foamable resin flowing from the gate 18 into the cavity 19 are shown. The direction in which the foamable resin flows is a direction substantially orthogonal to the tangential direction of the constant velocity line.

One direction out of the directions in which the foamable resin flows is defined as the x direction, and a first point A on the surface of the molded product is set in the vicinity of the gate 18, and the second point advances from the first point A in the x direction. Point A ′ is set. The area between the first point A and the second A ′ is an evaluation target in the quality prediction process.
Note that the quality prediction process is repeated by changing the positions of the first point A and the second point A ′ to be evaluated so that the quality of the surface shape of the molded product can be evaluated without fail.

In the present embodiment, the second point A ′ is located upstream (or downstream) in the flow direction of the foamable resin from the first point A, and the straight line connecting the first point A and the second A ′ is It is substantially parallel to the direction in which the foamable resin flows. Thus, according to the straight line connecting the first point A and the second A ′ being substantially parallel to the direction in which the foamable resin flows, the resin filling is completed between the first point A and the second A ′. Changes in physical quantities of the resin pressure P, the resin temperature T, and the gas solubility C in the resin become the most clear and desirable because the quality can be easily evaluated.
However, the straight line connecting the first point A and the second A ′ may be a direction substantially orthogonal to the direction in which the foamable resin flows (that is, a direction substantially parallel to the constant velocity line shown in FIG. 6).

  The resin pressure P and the resin temperature T at the completion of the resin filling obtained by the foam injection molding simulation between the first point A and the second point A ′ on the surface of the molded article determined as described above. Each physical quantity of the gas solubility C in the resin is extracted as physical quantity data for quality evaluation (S27) and acquired by the quality prediction device 36.

  In FIG. 7, the resin pressure P (FIG. 7 a), the resin temperature T (FIG. 7 b), and the gas solubility C (FIG. 7 c) in the resin at the time of resin filling in the first point A-second point A ′ cross section are as follows. An example is shown. FIG. 7 shows that the resin pressure P, the resin temperature T, and the gas solubility C become lower toward the upstream side of the flow of the foamable resin (that is, from the first point A toward the second point A ′). .

Subsequently, the quality prediction device 36 calculates an evaluation reference value R (S28).
The “evaluation reference value R” is an evaluation reference value of the surface quality of a molded product, and is a value related to density. It is believed that the surface quality of a foam injection molded product correlates with the density of the molded product.
Therefore, in order to evaluate the quality of the foam injection-molded product, the resin pressure P when the resin filling is completed, the resin temperature T, the gas solubility C in the resin, and the expansion amount when a part of the cavity 19 is expanded (core back) The evaluation reference value R is calculated by using a regression equation (the following [Equation 1]) including at least each physical quantity as a variable. The regression equation for calculating the evaluation reference value R is a regression equation relating to density, and is set in the quality prediction device 36 in advance.

[Formula 1]
R = f (P, T, C, L)
(Evaluation reference value R, resin pressure P, resin temperature T, gas solubility C, core back amount L)

  As shown in FIG. 8, in this embodiment, the line representing the evaluation reference value R at the first point A−the second point A ′ is a curve that gently falls from the first point A toward the second point A ′. In the vicinity of the second point A ′, the slope of the curve changes abruptly.

Foamed injection-molded products have poor quality such as dents on the surface where the slope of the evaluation reference value R changes abruptly.
Therefore, in order to determine whether the quality of the foam injection-molded product is good or not, the quality prediction device 36 uses a determination reference value Q (the following [Equation 1]) that is a differential value of the evaluation reference value R (absolute value of the differential value). Is calculated (S29).

  Furthermore, in the quality prediction device 36, the threshold value q set in advance for the determination reference value Q is compared with the calculated determination reference value Q. If the determination reference value Q is larger than the threshold value q, the quality failure is determined. Is determined (YES in S30).

  As shown in FIG. 9, in the present embodiment, the line representing the determination reference value Q at the first point A−second A ′ has a slope that increases rapidly in the vicinity of the second point A ′. Is over. For this reason, in the present embodiment, unevenness occurs on the surface of the molded product in the vicinity of the second point A ′, and it is determined that the quality is poor.

If the quality prediction device 36 does not determine that the quality is poor (NO in S30), the quality prediction process in the quality prediction system 30 is terminated, and the foam injection molding is performed favorably under the molding conditions. The effect is output and recorded by the quality prediction device 36.
On the other hand, when it is determined that the quality is poor in the process of step 30 by the quality predicting device 36 (YES in S30), the incidental conditions and molding conditions of the mold are changed (S31), and again from step S23. The process is repeated.
In addition, as ancillary conditions and molding conditions of the mold, one or more combinations of gate position, product plate thickness, injection speed, gas pressure, mold temperature, resin temperature, etc., are changed. It is given as an incidental condition or molding condition of the mold. The collateral conditions and molding conditions of these molds can be arbitrarily set by the operator, and the quality predicting device 36 is controlled to change each item by a predetermined quantity according to the program. You can also.

  In the quality prediction process by the quality prediction system 30 described above, an example of performing a process of calculating the determination reference value Q by two-dimensionally differentiating the evaluation reference value R in the x direction in the cross section of the first point A-second A ′. As described below, the evaluation reference value R at a point B on the surface of the molded product is expressed as a function of the x direction and the y direction substantially orthogonal to the x direction, and the evaluation reference value R is expressed in three dimensions. Thus, the determination reference value Q can be obtained by performing three-dimensional calculation of the product surface gradient at point B. In this case, for example, as shown in FIG. 10, the determination reference value Q can be obtained by the following [Equation 2] as a gradient of a point B on the surface of the molded product.

In the above [Equation 2], B ₀ is the coordinates of point B on the surface of the molded product, and B _{1 to} B ₄ are the coordinates of points on the surface of the molded product in the vicinity of point B. _Moreover, r 1 ~r ₄ from _{B 0,} the distance B 1 ~B _4.
In this way, the gradients at all points existing in the range where the quality of the surface of the molded product is to be predicted are calculated, and quality defects are determined based on the calculation results. Note that, for example, as shown in a color map in which the magnitude of the gradient is displayed for each color as shown in FIG.

The flowchart of the foam injection molding which concerns on the Example of this invention. The figure explaining the structure of a foam injection molding machine. The figure which shows the mode of the metal mold | die at the time of a core back. The block diagram of the quality prediction system which concerns on the Example of this invention. The flowchart of a quality prediction process. The figure which shows the mode of the hot water flow in a cavity. The figure which shows an example of each physical quantity at the time of the resin filling completion in an A-A 'cross section. The figure which shows an example of the evaluation reference value in A-A '. The figure which shows an example of the criterion value in A-A '. The figure explaining another form of the calculation method of a judgment reference value. The figure explaining an example of the output method of a judgment reference value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Injection apparatus 20 Mold 19 Cavity 30 Quality prediction system 32 CAD apparatus 34 CAE analysis apparatus 36 Quality prediction apparatus

Claims (10)

In a quality prediction system for predicting the surface quality of a foam injection molded product obtained by injecting and filling a foamable resin into a cavity in a mold and then expanding a part of the cavity to foam,
The surface quality of the molded product including each physical quantity as a variable at least, including the resin pressure at the completion of resin filling in the cavity, the resin temperature, the gas solubility in the resin, and the resin expansion amount when part of the cavity is expanded A regression equation for calculating the evaluation reference value is set, and the physical quantities obtained by the foam injection molding simulation between the first point and the second point on the surface of the molded product are substituted into the regression equation. An evaluation reference value calculating means for calculating the evaluation reference value;
Based on the evaluation reference value, a determination means for determining the quality of the surface quality of the molded product,
A quality prediction system for a foam injection molded product, comprising: In a quality prediction system for predicting the surface quality of a foam injection molded product obtained by injecting and filling a foamable resin into a cavity in a mold and then expanding a part of the cavity to foam,
CAD means for creating molded article finite element model data;
CAE analysis means for performing foam injection molding simulation based on the molded product finite element model data;
The surface quality of the molded product including each physical quantity as a variable at least, including the resin pressure at the completion of resin filling in the cavity, the resin temperature, the gas solubility in the resin, and the resin expansion amount when part of the cavity is expanded A regression equation for calculating the evaluation reference value is set, and each physical quantity obtained by the simulation between the first point and the second point on the surface of the molded article is substituted into the regression equation, An evaluation reference value calculating means for calculating an evaluation reference value;
Based on the evaluation reference value, a determination means for determining the quality of the surface quality of the molded product,
A quality prediction system for a foam injection molded product, comprising: The second point is located on the upstream side or the downstream side in the flow direction of the foamable resin from the first point,
A quality prediction system for a foam injection-molded article according to claim 1 or 2. The determination means includes
A differential value of the evaluation reference value is calculated, and when the differential value exceeds a preset threshold value, the surface quality of the foamed injection molded product is determined to be poor.
The quality prediction system of the foam injection-molded article as described in any one of Claims 1-3. In order to predict the surface quality of a foamed injection molded product obtained by injecting and filling a foamable resin into a cavity in a mold and then expanding a part of the cavity and foaming,
The surface quality of the molded product, including at least variables, each physical quantity of resin pressure, resin temperature, and gas solubility in the resin upon completion of resin filling in the cavity, and the amount of expansion when expanding a part of the cavity. A computer with a regression formula for calculating the evaluation standard value is set in advance.
Obtain the physical quantities obtained by the foam injection molding simulation between the first point and the second point on the surface of the molded product, substitute the obtained physical quantities into the regression equation, and evaluate reference values. An evaluation reference value calculation process for calculating
A quality prediction program for a foamed injection-molded product, wherein a determination process for determining whether the surface quality of the molded product is good or not is executed based on the evaluation reference value. In the determination process,
A differential value of the evaluation reference value is calculated, and when the differential value exceeds a preset threshold value, the surface quality of the foamed injection molded product is determined to be poor.
A quality prediction program for a foam injection molded product according to claim 5. Foam injection molding obtained by providing an evaluation reference value calculating means and a determining means, and injecting and filling a foamable resin into a cavity in a mold and then expanding a part of the cavity to foam In the quality prediction system that predicts the surface quality of products,
In the evaluation reference value calculation means, at least the physical quantities of the resin pressure at the completion of resin filling into the cavity, the resin temperature, the gas solubility in the resin, and the expansion amount when part of the cavity is expanded are at least variables. Including a step of setting a regression equation for calculating the evaluation standard value of the surface quality of the molded article,
In the evaluation reference value calculating means, the physical quantities obtained by the foam injection molding simulation between the first point and the second point on the surface of the molded product are substituted into the regression equation, and the evaluation reference Calculating a value;
In the determination means, based on the evaluation reference value, determining the quality of the surface quality of the molded product,
A method for predicting the quality of a foam injection molded product, comprising: A CAD unit, a CAE analyzing unit, an evaluation reference value calculating unit, and a determining unit are provided. After the foamable resin is injected and filled into the cavity in the mold, the part of the cavity is expanded and foamed. In the quality prediction system that predicts the surface quality of the foam injection molded product obtained by
Creating the finite element model data of the molded product by the CAD means;
Performing foam injection molding simulation on the basis of the molded product finite element model data in the CAE analysis means;
In the evaluation reference value calculation means, at least the physical quantities of the resin pressure at the completion of resin filling into the cavity, the resin temperature, the gas solubility in the resin, and the expansion amount when part of the cavity is expanded are at least variables. Including a step of setting a regression equation for calculating the evaluation standard value of the surface quality of the molded article,
In the evaluation reference value calculation means, the physical quantities obtained by the simulation between the first point and the second point on the surface of the molded product are substituted into the regression equation, and the evaluation reference value is calculated. A calculating step;
In the determination means, based on the evaluation reference value, determining the quality of the surface quality of the molded product,
A method for predicting the quality of a foam injection molded product, comprising: The second point is located on the upstream side or the downstream side in the flow direction of the raw material resin from the first point,
A method for predicting the quality of a foam injection molded product according to claim 7 or 8. The determination means includes
A differential value of the evaluation reference value is calculated, and when the differential value exceeds a preset threshold value, the surface quality of the foamed injection molded product is determined to be poor.
The method for predicting the quality of a foam injection molded product according to any one of claims 7 to 9.

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