JPH09262887A - Simulation method of mold shrinkage process in crystalline resin molding and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate a shrinkage factor by a method wherein the PVT curve of resin in accordance with the crystallization behavior in molding and the specific volume of the resin are calculated. SOLUTION: The outputs from an input part 11, in which various data necessary for analysis are fed to a PVC characteristic curve analysing part 12 for calculating the PVC characteristic curve of resin at any crystallinity, a PVC curve calculating part 13 for calculating the PVC curve of resin in accordance with the crystallization behavior at molding and a specific volume calculating part 14 of the resin. The output of the PVC curve calculating part 13 is fed to a storage part A16 and the specific volume calculating part 14. The output of the specific volume calculating part 14 is fed to a storage part, in which the analytical result is stored, and to a shrinkage factor calculating part 15 for calculating the shrinkage factors at molding. The output of the shrinkage factor calculating part 15 is fed to the storage part, in which the analytical result is stored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for simulating a molding process of a crystalline resin molded product,
More specifically, the present invention relates to a shrinking process simulation method and apparatus capable of predicting the amount of molding shrinkage including shrinkage due to crystallization, which is indispensable for analysis of warpage, sink marks, and shrinkage of molded products.

[0002]

2. Description of the Related Art In recent years, it is possible to predict a shape defect closer to an actual molding phenomenon by analyzing a deformation behavior of a resin in a mold and a temperature behavior in the mold after the deformation starts, which has not been considered in recent years. A molding process simulation system has been developed.

For example, in the injection molding process simulation system disclosed in Japanese Examined Patent Publication No. 6-22840, a change in resin temperature in the molding process is calculated, and at the time when the molten phase of the molding material is disconnected due to the decrease in the resin temperature due to cooling. After that time, the deformation due to cooling is calculated using the linear expansion coefficient of the resin calculated from the PVT data of the resin.

However, this method does not consider crystal shrinkage of the crystalline resin at all, and therefore has a problem that the calculation result of the shrinkage ratio for the molding of the crystalline resin is estimated to be smaller than the actual shrinkage ratio. .

Further, Japanese Patent Laid-Open No. 4-282746 proposes a method for evaluating the appearance defect of a molded product. In this method, the filling analysis of the injection-molded product, the holding pressure flow analysis, and the resin cooling analysis are sequentially performed, and the temperature change of the molding material during the injection molding process,
Calculate the pressure and specific volume change, and calculate the temperature distribution of the molded product during mold release or removal based on the calculation results, and the heat shrinkage and crystallites from the calculated distribution temperature to the ambient temperature. The shrinkage amount evaluation index value M is calculated by the following equation by accumulating the crystal shrinkage amount in consideration of the crystallization rate in the crystallization region.

[0006]

## EQU1 ## M = α (T-T0) + βf [(T-T0) / t] (1) where α: linear expansion coefficient, β: 100% crystal shrinkage,
T: take-out temperature, T0: outside air temperature, f: function, t: time, where f defines a function for obtaining an increase in crystallinity from the take-out temperature to the outside air temperature. it is obvious.

[0007]

However, although this method can predict the occurrence of mella, it cannot quantitatively calculate the change in specific volume and shrinkage during molding, and it cannot be calculated from the temperature taken out from the outside air. There is a problem that a function for accurately calculating the increment of crystallinity up to temperature cannot be defined.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a shrinkage process simulation method and apparatus for quantitatively predicting a specific volume and a shrinkage rate in a molding process in a crystalline resin. .

[0009]

That is, the present invention uses the data of resin temperature, pressure, and crystallinity in the molding process and the method for determining the PVT characteristics of the resin at an arbitrary crystallinity, and the crystallization behavior during molding is A method for simulating a molding shrinkage process in a crystalline resin molded article, which is characterized by calculating a PVT curve of a resin and a specific volume of the resin, and further predicting a shrinkage ratio, an amorphous resin, a supercooled liquid, and a crystalline resin. Determine the temperature and pressure dependence of the specific volume in each state, further from the specific volume and crystallinity of crystals and amorphous, or crystals and supercooled liquid,
A method for determining the PVT characteristics of a resin at an arbitrary crystallinity, a specific volume considering only heat shrinkage from the actually measured PVT curve of the resin, and a crystallinity from a crystalline and amorphous specific volume at room temperature. And a change in the specific volume due to crystal shrinkage, and a method for obtaining the PVT characteristic of the resin at an arbitrary crystallinity from the two, a data input section for inputting at least resin temperature, pressure, and crystallinity data in the molding process. And a PVT characteristic analysis section for obtaining the PVT characteristic of the resin at an arbitrary crystallinity, and a PVT curve of the resin and a specific volume of the resin according to the crystallization behavior at the time of molding P
A shrinkage process in a crystalline resin molded product, characterized by comprising a VT curve analysis unit, a specific volume calculation unit, and a shrinkage ratio calculation unit for predicting the shrinkage ratio, and calculating changes in the specific volume and shrinkage ratio during the molding process. A molding apparatus and a molding process simulation system for supporting manufacturing, which incorporates the above-described molding shrinkage process simulation method to calculate the design of a resin molded product, warpage, sinking, and shrinkage of the molded product. System, a method of setting molding conditions of a resin molded product, characterized by optimizing molding condition setting by calculating warp, sink, shrinkage of the molded product using the molding process simulation system, By using the shrinkage process simulation method to calculate the shrinkage of the molded product,
A method for designing a mold characterized by optimizing a mold shape, characterized in that the mold shape is optimized by calculating shrinkage of a molded product using the above-mentioned molding process simulation system. A method for designing a mold, a mold designed by the method for designing a mold, and a molded article characterized by molding a resin or a resin composition under the molding conditions set by using the method for setting the molding conditions. A manufacturing method, a method for manufacturing a molded article characterized by molding using the above-mentioned mold, and a molded article manufactured by the above manufacturing method.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the molding shrinkage process simulation method of the present invention, data of resin temperature, pressure and crystallinity in the molding process and PVT of resin at an arbitrary crystallinity are used.
It is necessary to find a method for obtaining the characteristics. In addition, in the present invention, the PVT characteristic means a property peculiar to a substance existing between the pressure P, the specific volume V, and the temperature T. What is a PVT curve? A specific volume V is obtained as a function of a pressure P and a temperature T according to a PVT characteristic, and a change in the specific volume V obtained when the pressure P and the temperature T are selected on both axes of the graph is obtained when illustrated. A curved line.

The method for obtaining the resin temperature, pressure, and crystallinity in the molding process is not particularly limited, but can be calculated, for example, by sequentially performing filling analysis, holding pressure analysis, and cooling analysis by an existing molding process simulation system. it can.

Also, the PVT of the resin at any crystallinity
It is desirable to use the following method (A) or (B) as a method for obtaining the characteristics.

(A) The temperature and pressure dependence of the specific volume of the resin in the amorphous, supercooled liquid and crystal states are determined, and the specific volume and crystallinity of the crystal and the amorphous, or the crystal and the supercooled liquid. To determine the PVT characteristics of the resin at any crystallinity.

(B) The specific volume considering only heat shrinkage was determined from the actually measured PVT curve of the resin, and the change in the specific volume due to the crystallinity and the crystal shrinkage was calculated from the crystalline and amorphous specific volumes at room temperature. Is obtained, and the PVT characteristics of the resin at an arbitrary crystallinity are obtained from the two relationships.

The above methods (A) and (B) will be described in detail below.

First, the method (A) will be described.

FIG. 2 is a conceptual diagram showing the relationship between the temperature and the specific volume of each of the amorphous, supercooled liquid, and crystalline states of the resin at atmospheric pressure. However, the specific volume of the crystal at Vc 0: 0K (cm ³ / g), the specific volume of the amorphous at Vg 0: 0K, ΔVg: the difference between the specific volume of the crystal and the amorphous at a temperature below the glass transition temperature Tg, ΔVm: the melting point Tm , The difference in specific volume between the liquid and the crystal, El: thermal expansion coefficient of liquid, supercooled liquid (cm ³ / gK), Eg: amorphous thermal expansion coefficient, Ec: thermal expansion coefficient of the crystal, and The coefficient of thermal expansion Eg of the amorphous material and the coefficient of thermal expansion Ec of the crystalline material at the glass transition temperature or lower are equal. The specific volumes of the amorphous, supercooled liquid and crystals at the temperature T are calculated by the following equations (2), (3) and (4).

[0018]

## EQU00002 ## Vg (T) = Vg0 + Eg.T = Vc0 + .DELTA.Vg + Ec.T (2) where Vg (T) is the amorphous specific volume at temperature T, where T is 0
It is the temperature (K) from K to the glass transition temperature.

[0019]

## EQU00003 ## Vl (T) = Vc0 + El.T = Vg (Tg) + El. (T-Tg) (3) where Vl (T) is the amorphous specific volume at temperature T, where T is the glass transition temperature or higher. Is.

[0020]

## EQU4 ## Vc (T) = Vc0 + Ec.multidot.T (4) where Vc (T): specific volume of crystal at temperature T, T is 0
The temperature is from K to the melting point. In addition, ΔVg is the following formula (5)
You can ask for it.

[0021]

ΔVg = Vl (Tg) -Vc (Tg) (5) Therefore, if at least El, Ec, and Vc0 are known, the relation between the temperature and the specific volume at atmospheric pressure for the amorphous, supercooled liquid, and crystal is expressed by the formula ( 2) (3) (4) can be obtained.

The relationship between the pressure and the specific volume can be obtained by performing the calculation according to the Tait equation of the following equation (6).

[0023]

[Equation 6] V (P, T) = V (0, T) [1-C · ln (1 + P / B (T))] (6) where P: pressure, V (P, T): pressure P, It is a term showing the temperature dependence of the formulas of specific volume at temperature T, C: constant, B (T): Tait.

As described above, the equations (2), (3), (4), (5) and (6)
Thus, the pressure-specific volume-temperature relationship can be obtained for amorphous, supercooled liquid, and crystal.

Further, assuming that the crystallinity at the time of molding is x, the resin temperature T, the pressure P (MPa), and the specific volume Vx (P, T) at the crystallinity x (T) can be calculated by the following equation. I can.

[0026]

## EQU00007 ## Vx (P, T) = Vc (P, T) .multidot. (1-x (T)) + Vl (P, T) .x (T) = [Vc (0, T). (1-x (T)) + Vl (0, T) .x (T)]. [1-C.ln (1 + P / B (T))] (7) However, the expression (7) relates to the temperature from the glass transition temperature to the melting point. That is, below the glass transition temperature, not the specific volume Vl of the supercooled liquid but the amorphous specific volume Vg is used. Further, as is clear from the formula (7), the pressure dependence of the specific volume may be considered after first calculating the crystallinity x (T) under atmospheric pressure. Above, the formulas (2) (3) (4) (5)
(6) P of the resin at an arbitrary crystallinity according to (7)
VT characteristics can be obtained.

Next, a method for obtaining the PVT characteristic of the resin at the arbitrary crystallinity (B) will be described.

According to the method (B), the PVT characteristics of the resin at any crystallinity are obtained by determining the specific volume only by thermal contraction from the actually measured PVT curve of the resin, and the crystalline and amorphous at room temperature. The relationship between the crystallinity and the change in the specific volume due to crystal shrinkage is obtained from the specific volume of, and both are obtained.

FIG. 3 shows a PVT curve prepared by combining pressure-specific volume data measured for a polybutylene terephthalate resin under isothermal conditions. A point Vc shown in the figure indicates a crystal at atmospheric pressure and room temperature. Specific volume, Vl
Is an amorphous specific volume. It can be seen from FIG. 3 that the specific volume changes abruptly between the temperatures Ta and Tb, but this is due to shrinkage due to crystallization. The measurement is performed by changing the pressure at a constant temperature as in the PVT measurement, or the temperature is raised by several degrees centigrade per minute,
Under the condition that the measurement is performed by cooling, crystallization occurs in a narrow temperature range Ta and Tb near the melting point, and further crystallization hardly progresses at a temperature of Tb or lower. Then, it is safe to assume that only heat shrinkage will occur. Further, it can be considered that the change in the specific volume due to heat shrinkage is constant regardless of the crystallinity. Since the crystal shrinkage due to crystallization is obtained by the difference between the specific volume of the amorphous at room temperature and the actually measured atmospheric pressure, the specific volume at room temperature,
After all, the specific volume of the resin in the case of considering only the heat shrinkage is not affected by the crystallization at the temperature of Ta or more from the actually measured PVT curve of the resin, and thus the actually measured PVT is obtained.
The curve can be used as it is, and at a temperature of Tb or lower, the PVT curve can be obtained by translating upward by Vl-V in order to cancel the crystal shrinkage. The specific volume at a temperature between Tb and Ta is not particularly required because the cooling rate during molding is very fast and crystallization occurs at a temperature lower than Tb. V
It is also possible to formulate each curve of the specific volume that has been translated upwards by a mathematical expression by least-squares approximation or the like, and apply this at temperatures of Tb and Ta to obtain it.

On the other hand, regarding the relationship between the crystallinity and the change in specific volume due to crystal shrinkage, the specific volume (V
From c) and the amorphous specific volume (Vl), when the crystallinity is x (T), the change in specific volume due to crystal shrinkage Vh (T) is calculated by the following equation (8).

[0031]

## EQU8 ## Vh (T) = (V1-Vc) .multidot.x (T) (8) However, the change in specific volume due to crystal shrinkage Vh (T) is not affected by pressure. Therefore, the PVT characteristic of the resin in consideration of crystallization is obtained by substituting the crystallinity x (T) at the temperature T into the equation (8) and changing the specific volume due to crystal shrinkage Vh.
It can be calculated by calculating (T) and moving the specific volume of the resin considering only the heat shrinkage downward by Vh (T) in the vertical axis direction.

By using the above method (A) or (B), the PVT characteristic of the resin at any crystallinity can be obtained. Therefore, the data of the resin temperature and pressure in the molding process and the crystallinity are used. The PVT curve of the resin and the specific volume of the resin can be calculated according to the crystallinity of the molding process. It should be noted that which of the above methods (A) and (B) is selected is arbitrary.

Further, if the relationship between the resin temperature T and the time t at the time of molding can be obtained by a molding process simulation or the like, it is also possible to obtain the change with time of the specific volume of the resin.

Then, the volume shrinkage ratio at the temperature T is Sv
If (T) and the linear shrinkage ratio are Sl (T), the change in shrinkage ratio can be predicted by the following equation.

[0035]

Sv (T) = 1-V (T) / Vs (9) Sl (T) = 1- (V (T) / Vs) ^1/3 where Vs is the specific volume at the start of contraction, Shrinkage start temperature Ts
It is required by defining. If the relationship between the resin temperature T and the time t at the time of molding can be obtained, the change in shrinkage rate with time can also be obtained. Also, the contraction start temperature T
Regarding s, it is preferable to set Ts to a temperature at which the gate solidifies and resin does not flow into the cavity, a temperature at which each part of the resin solidifies and the resin does not flow, and a temperature at which the pressure reaches atmospheric pressure.

In the present invention, the above-described molding shrinkage process simulation method can be incorporated into a molding process simulation system for supporting the design and manufacture of a resin molded product to calculate the warp, sink mark and shrinkage of the molded product. The method of incorporating the molding shrinkage process simulation method into such a molding process simulation system is not particularly limited, but it can be incorporated in addition to the conventional molding process simulation system. The molding process simulation system capable of incorporating the molding shrinkage process simulation method by the conventional method is preferably replaced.

Further, a mold capable of molding a molded product having a desired shape and size by predicting the shrinkage rate by using the above-described molding shrinkage process simulation method and designing the mold in consideration of the shrinkage rate. It is possible to design, and by using the mold thus obtained, it is possible to obtain a molded product having a desired shape and size. In this case, it is more accurate to use the following molding process simulation system and to include the mold design as part of the optimization of molding conditions, rather than simply using the above-mentioned molding shrinkage process simulation method, to mold the desired shape and size. You can get the goods.

Further, by using the molding process simulation system incorporating the above-mentioned molding shrinkage process simulation method, the warp, sink and shrinkage of the molded product are calculated to set molding conditions such as mold temperature, injection temperature and holding pressure. Can be optimized to set molding conditions for the resin molded product. The method of optimizing the molding conditions is not particularly limited, but as conventionally used, sled, sinker,
It is preferable that the relationship between the shrinkage ratio and the resin temperature, pressure, and mold temperature be investigated by simulation and further studies be repeated.

Further, a mold capable of molding a molded product having a desired shape and size by predicting the shrinkage rate by using the above-described molding shrinkage process simulation method and designing the mold in consideration of the shrinkage rate. It is possible to design, and by using the mold thus obtained, it is possible to obtain a molded product having a desired shape and size. In this case, it is more accurate to include the mold design as a part of the optimization of the molding conditions by using the molding process simulation system, rather than only using the molding shrinkage process simulation method, to have a desired shape and size. A molded product can be obtained.

The shrinkage process simulation apparatus of the present invention includes a data input unit for inputting at least data of resin temperature, pressure, and crystallinity in the molding process, and a PVT characteristic analysis unit for obtaining PVT properties of the resin at an arbitrary crystallinity. And a PVT curve analysis unit for calculating the PVT curve of the resin and the specific volume of the resin according to the crystallization behavior during molding, a specific volume calculation unit, and a shrinkage ratio calculation unit for predicting the shrinkage ratio. Is.

In this apparatus, the PVT characteristic analysis unit obtains the PVT characteristic of the resin at an arbitrary crystallinity using the data input in the data input unit, and the data input in the data input unit in the PVT curve analysis unit are used. The PVT curve of the resin according to the crystallization behavior during molding is obtained from both of the PVT characteristics obtained by the PVT characteristic analysis unit, and the specific volume of the resin is calculated by the specific volume calculation unit using this PVT curve.

The apparatus for simulating the shrinkage process in the crystalline resin molded product of the present invention is not limited as long as it has a configuration satisfying the above-mentioned requirements, but preferably the calculation unit is provided in a single calculation device. , Or all parts are configured by independent computing devices,
It is desirable that each device be connected by a data transfer device.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 shows an electrical configuration (block diagram) of an apparatus to which the shrinkage process simulation method for crystalline resin of the present invention is applied.

In the figure, the output of the input section 11 for inputting various data required for analysis is in accordance with the PVT characteristic analysis section 12 for obtaining the PVT characteristic of the resin at an arbitrary crystallinity and the crystallization behavior during molding. PV to obtain PVT curve of resin
The output from the PVT characteristic analysis unit 12 is led to the T curve calculation unit 13 and the specific volume calculation unit 14 that calculates the specific volume of the resin, and the output from the PVT curve calculation unit 13 is output from the PVT curve calculation unit 13. Is led to the storage unit A17 for storing the analysis result and the specific volume calculation unit 14, and the output of the specific volume calculation unit 14 is the storage unit B18 for storing the analysis result and the contraction for calculating the change of the contraction rate at the time of molding. The output of the contraction rate calculation unit 15 is guided to the rate calculation unit 15, the storage unit B18 that stores the analysis result, and the output unit 16 that graphically displays the result. The storage unit A17 and the storage unit B18 are not always necessary, but by storing the analysis result as data, it can be used for verification of the accuracy of simulation. The storage medium of the storage unit is not particularly limited to a floppy disk or a compact disk.

The input section 11 inputs various data necessary for analysis, such as changes in resin temperature, pressure and crystallinity at the time of molding, and data obtained by digitizing the actually measured PVT curve of the resin.

FIG. 4 shows a polybutylene terephthalate resin pellet (relative viscosity: 1.45) having a length of 80 mm and a width of 8
The relationship between resin temperature, pressure, and crystallinity at the time of molding of a 0 mm × 3 mm thick rectangular plate-shaped product is expressed by the injection molding process simulation device (“TIMON” manufactured by Toray Industries, Inc.) and the Avrami formula. It is obtained by performing a crystallization simulation based on this, and this is converted into data and input to the input unit 11, and the PVT curve actually measured is also converted into a numerical value and input to the input unit 11. This is equivalent to incorporating the molding shrinkage process simulation method according to claim 1 into a molding process simulation system for supporting the design and manufacturing of a resin molded product, and calculating the warp, sink mark and shrinkage ratio of the molded product. .

The PVT characteristic analysis unit 12 calculates the PVT characteristic of the resin at any crystallinity. FIG. 5 shows the PVT characteristics of the polybutylene terephthalate resin in the supercooled liquid, liquid, and crystal calculated by the method of the second invention, where El, Ec, and Vc required for the calculation are the Van der Waals volume Vw of the resin. (Vw = 114.
6 (cm ³ / mol)), but this does not limit the method for obtaining El, Ec, and Vc (0).

[0049]

[Equation 10] El = 0.001 · Vw / Mw Ec = 0.00045 · Vw / Mw (10) Vc (0) = 1.3 · Vw / Mw−D where Mw: molecular weight (M = 220 (g / Mol)),
D: As a correction term, D = 0.041 was used, but the value can be obtained from crystalline or amorphous specific volume at room temperature. Also, a constant C necessary for calculating the pressure dependence by the Tait equation and a function B showing the temperature dependence.
Regarding (T), the constant C was calculated using the average value C = 0.00894 obtained for various resins, and B (T) was calculated using the function of the following equation.

[0050]

B (T) = B0 · exp (−B1 · (T−273.14)) (11) However, B0 and B1: are constants.

The PVT curve analysis unit 13 calculates the PVT curve of the resin according to the crystallization behavior during molding. FIG. 6 shows a PVT curve of a resin calculated based on the input data of the resin temperature and the crystallinity shown in FIG. 4 using the method of the second invention, and FIG. 7 shows the method of the third invention. And the PVT characteristics of the resin calculated based on the input data of resin temperature and crystallinity shown in FIG.

In the specific volume calculation unit 14, the resin temperature, pressure, and crystallinity data input by the input unit 11 and the PVT curve of the resin in accordance with the crystallization behavior at the time of molding obtained by the PVT curve analysis unit 13 are calculated. Calculate the specific volume of the resin during molding from.
FIG. 8 is a graph showing the specific volume at the time of molding using the resin temperature, pressure and crystallinity data shown in FIG. 4 and the PVT characteristics of the resin calculated by the method of the second invention as shown in FIG. The PVT characteristics of the resin shown in FIG. 6 are also shown by dotted lines in the figure in order to clearly show the relationship between the pressure, the crystallinity and the specific volume, as a result of calculating the change.

In the contraction rate calculating section 15, the specific volume calculating section 14
The change in shrinkage rate during molding is calculated using the result obtained in. FIG. 9 shows the change in linear shrinkage during molding. Se shown in the figure is the result of actually measuring the molding shrinkage (linear shrinkage) of the molded product, which is calculated using the present invention. The results and the actually measured results are in good agreement.

[0054]

【The invention's effect】

(1) The shrinkage process simulation method and apparatus for a crystalline resin molded article according to the present invention provides a method for obtaining data of resin temperature, pressure and crystallinity during the molding process and a PVT characteristic of the resin at an arbitrary crystallinity. It was configured to calculate the PVT curve of the resin and the specific volume of the resin according to the crystallization behavior during molding, and to predict the shrinkage rate, so calculate the shrinkage rate that matches the crystallinity during molding. In addition, it is possible to calculate an appropriate shrinkage amount as compared with the conventional method.

(2) The temperature and pressure dependence of the specific volume of the resin in each state of amorphous, supercooled liquid and crystal is determined, and further the specific volume and crystallinity of the crystal and the amorphous or the crystal and the supercooled liquid. By the method of obtaining the PVT characteristics of the resin at an arbitrary crystallinity from the above, the labor for actually measuring the PVT curve of the resin can be reduced, and further, the PVT characteristics of the resin having various crystallization behaviors for various resins can be obtained. I can do things.

(3) The specific volume considering only heat shrinkage was determined from the actually measured PVT curve of the resin, and the change in specific volume due to crystallinity and crystal shrinkage was calculated from the crystalline and amorphous specific volumes at room temperature. Of the resin at an arbitrary crystallinity from both of them, the PV at an arbitrary crystallinity can be easily obtained from the actual PVT curve.
The T curve can be obtained, and the PVT characteristics of the resin having various crystallization behaviors can be obtained.

(4) According to the molding process simulation system of the present invention, in the molding process simulation system for supporting the design and manufacturing of the resin molded product, the above-described molding shrinkage process simulation method is incorporated to bend the molded product. By calculating sink marks and shrinkage rates, new functions such as obtaining the PVT curve of the resin in the molding process can be added to the molding process simulation system, and the shrinkage rate calculation results can be used for sinking, warping, etc. of molded products. By using it for the analysis of the deformation related to the shrinkage of the molded product, it is possible to achieve various effects such that the accuracy of the analysis can be improved.

(5) According to the molding condition setting method of the present invention, a molding process simulation system for supporting the design and manufacturing of a resin molded product, which incorporates the molding shrinkage process simulation method, is used. In order to optimize the setting of molding conditions such as mold temperature, injection temperature, holding pressure, etc. by calculating warpage, sink marks, shrinkage ratio,
When the quality standard of a molded product is set by the shrinkage amount, the present invention can be used to set an appropriate molding condition.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a shrinkage process simulation device to which a shrinkage process simulation method for a crystalline resin of the present invention is applied.

FIG. 2 is a conceptual diagram showing the relationship between the resin temperature and the specific volume under atmospheric pressure.

FIG. 3 is a PVT measurement result of polybutylene terephthalate.

FIG. 4 shows the relationship among resin temperature, pressure, and crystallinity during molding of a polybutylene terephthalate resin molded product.

FIG. 5 is a graph showing PVT characteristics of a polybutylene terephthalate resin in a supercooled liquid, a liquid, and a crystal calculated by the method of the second invention.

FIG. 6 shows a result of calculating a PVT curve of a resin according to a crystallization behavior during molding by using the method of the second invention.

FIG. 7 shows the results of calculating the PVT curve of the resin according to the crystallization behavior during molding, using the method of the third invention.

FIG. 8 shows the results of calculating the change in specific volume during molding using the PVT curve of the resin calculated by the method of the second invention.

FIG. 9 shows changes in linear shrinkage during molding.

[Explanation of symbols]

 11. Data input section 12. PVT characteristic analysis unit 13. PVT curve calculation unit 14. Specific volume calculation unit 15. Shrinkage rate calculator 16. Output unit 17. Storage unit A 18. Memory B

Claims (12)

[Claims] 1. A method for determining the PVT characteristic of a resin at a desired crystallinity and the data of the resin temperature, pressure and crystallinity during the molding process, to determine the P of the resin according to the crystallization behavior during molding.
A method for simulating a molding shrinkage process in a crystalline resin molded product, which comprises calculating a VT curve and a specific volume of a resin, and further predicting a shrinkage rate. 2. The temperature and pressure dependence of the specific volume of the resin in each state of amorphous, supercooled liquid, and crystal are determined, and further, from the specific volume and crystallinity of the crystal and the amorphous, or the crystal and the supercooled liquid. , A method for obtaining PVT characteristics of a resin at an arbitrary crystallinity. 3. A specific volume in which only heat shrinkage is taken into consideration is obtained from an actually measured PVT curve of a resin, and a change in specific volume due to crystallinity and crystal shrinkage is calculated from crystalline and amorphous specific volumes at room temperature. A method of obtaining the relationship and then obtaining the PVT characteristic of the resin at an arbitrary crystallinity from the two. 4. A data input section for inputting data of resin temperature, pressure and crystallinity at least during a molding process, a PVT characteristic analysis section for obtaining a PVT characteristic of resin at an arbitrary crystallinity, and a PVT characteristic analyzing section for molding the resin from both of them. P of resin according to crystallization behavior
A PVT curve analysis unit for calculating the VT curve and the specific volume of the resin,
A shrinkage process simulation device for a crystalline resin molded product, comprising a specific volume calculation unit and a shrinkage ratio calculation unit that predicts a shrinkage ratio, and calculates changes in specific volume and shrinkage ratio during the molding process. 5. A molding process simulation system, which incorporates the molding shrinkage process simulation method according to claim 1 in a molding process simulation system for supporting the manufacture of a resin molded product. 6. Molding in a resin molded product, characterized in that the setting of molding conditions is optimized by calculating the warp, sink mark and shrinkage of the molded product using the molding process simulation system according to claim 5. How to set the conditions. 7. A method for designing a mold, which comprises optimizing a mold shape by calculating a shrinkage rate of a molded product by using the molding shrinkage process simulation method. 8. A method of designing a mold, wherein the mold shape is optimized by calculating the shrinkage rate of a molded product using the molding process simulation system according to claim 5. 9. A mold designed by the mold designing method according to claim 7. 10. A method for producing a molded article, which comprises molding a resin or a resin composition under the molding conditions set by using the molding condition setting method according to claim 6. 11. A method of manufacturing a molded article, which comprises molding using the mold according to claim 7. 12. A molded product manufactured by the manufacturing method according to claim 11.