JP3406083B2 - Molding mold design method and design support system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die designing method and a design support system capable of quantitatively evaluating the thermal deterioration amount of resin during temperature increase / decrease with the largest heat load.
It is related to CAE (CAD) system for mold / material design.

[0002]

2. Description of the Related Art Conventionally, as a method for predicting the degree of deterioration of a heat-degradable resin, for example, there is a flow analysis evaluation system for an injection molding die described in Japanese Patent Application Laid-Open No. 5-189526.

This system is a system for evaluating a gate size for preventing burnout, which is a defective appearance that occurs at the time of injection molding, and performs a resin filling analysis by using a resin gate passage flow rate and a gate diameter as parameters. As a result, a filling analysis unit that calculates the distribution of pressure, temperature, etc., and an index calculation unit that calculates an index value that represents the burn for each gate diameter with a constant gate passage flow rate, based on the analysis result, were calculated. Based on the relationship between the index value and each parameter, the display unit is configured to create and display a chart in which the horizontal axis represents the amount of resin passing through the gate and the vertical axis represents the index value representing the burn.

That is, the change in resin temperature during the filling process in injection molding is calculated, and the burnout, which is the appearance quality of the product, is predicted based on the maximum temperature during filling.

[0005]

As described above, the conventional flow analysis and evaluation system for injection molding dies simulates a short-time phenomenon called the filling process in the molding process, and the instantaneous temperature of the result is simulated. Only the (maximum temperature during filling) is used to evaluate the occurrence of burns.

That is, in the conventional system, the thermal history of the largest heat load on the resin (that is, the most likely thermal degradation) and the unsteady process (for example, at the start or stop) is predicted. However, since it is not configured to use this as the data for predicting thermal deterioration, there is a problem that it is not possible to design a mold that also considers unsteady processes. In other words, the conventional system can sufficiently cope with the phenomenon of filling, which is a high temperature and a short time, but the thermal deterioration phenomenon of the resin is a function of temperature and time. It cannot be applied to the prediction of low temperature and long term thermal deterioration phenomena such as when stopped (when the temperature is raised or lowered).

Further, the conventional system only evaluates the occurrence of burns, and cannot evaluate the degree of deterioration of the resin before the burns occur. Therefore, the process stability against burns cannot be evaluated. was there.

The present invention was devised to solve such a problem, and an object thereof is a molding metal capable of quantitatively evaluating the thermal deterioration amount of the resin at the time of temperature increase / decrease with the largest heat load. To provide a mold design method and a design support system.

[0009]

In order to solve the above-mentioned problems, the method of designing a molding die according to claim 1 of the present invention comprises:
Based on various data such as mold equipment data, resin physical property data, initial temperature data, and cooling condition data, heat history data during temperature increase / decrease, which is temperature data of the mold and resin at each time, is calculated, and obtained by measurement. A first approximation formula showing the relationship between the degree of thermal deterioration and the amount of change in the degree of thermal deterioration for each temperature, based on the thermal deterioration characteristic data with the temperature and time as parameters.
And a second approximate expression indicating the relationship between the thermal deterioration degree change amount and the temperature is obtained, and the thermal deterioration degree change amount is calculated from the second approximate expression based on the temperature data at a certain time of the thermal history data,
The heat deterioration degree is calculated from the first approximation formula based on the calculated heat deterioration degree change amount and the time data of the heat history data, and the heat deterioration degree up to the current calculation time is calculated by integrating the heat deterioration degree. Calculate the heat deterioration degree at each time by repeating this until the final time, and then, based on the mold device data, the heat deterioration data of the final time, and the heat deterioration limit value, the quality of the mold device is determined. In addition to performing the above, the heat deterioration degree correlation data with respect to the mold device parameters is calculated.

Further, according to a second aspect of the present invention, there is provided a molding die design support system in which various data such as mold equipment data, resin physical property data, initial temperature data and cooling condition data are used as input data. The heat history calculation unit that calculates the heat history data when the temperature is rising and falling, which is the temperature data of the resin at each time, and the temperature deterioration characteristics data with the temperature and time obtained by the measurement as parameters are input data, and A heat deterioration characteristic calculation unit that obtains a first approximate expression indicating a relationship between the heat deterioration degree and the change amount of the heat deterioration degree, and a second approximate expression indicating a relationship between the change amount of the heat deterioration degree and the temperature, and the heat history. The heat deterioration degree change amount is calculated from the second approximation formula based on the temperature data of the heat history data obtained at a certain time by the calculation unit, and the calculated heat deterioration degree change amount and the time data of the heat history data are calculated. And based on the above Calculating a degree of thermal degradation than one approximation formula,
By accumulating this, the heat deterioration degree up to the current calculation time is calculated, and this is repeated until the final time to calculate the heat deterioration degree at each time, the mold device data, the heat deterioration degree. The optimum mold that determines the quality of the mold device and calculates the heat deterioration degree correlation data for the mold device parameters, using the heat deterioration data and the heat deterioration limit value of the final time obtained by the temperature calculation unit as input data. And a design section.

[0011]

In the heat history calculation unit, various data such as mold device data, resin physical property data, initial temperature data and cooling condition data are used as input data, and the temperature data of the mold and the resin at each time is a temperature rise / fall temperature. Calculate historical data.

Here, the mold device data means, for example, data on material properties such as the shape, heat capacity, and thermal conductivity of mold parts. Further, the resin physical property data refers to data such as heat capacity and thermal conductivity of the resin. The initial temperature data means initial temperature data of the mold and the resin. Further, the cooling condition data refers to data such as the outside air temperature.

The thermal history calculation unit uses a numerical analysis method including a finite element method, a difference method, a boundary element method, a FAN method, etc., based on these input data, during temperature increase / decrease (unsteady process).
Calculate the heat history data of the mold or resin.

The heat deterioration characteristic calculation unit uses the heat deterioration characteristic data obtained by the measurement as parameters for the temperature and the time, as input data, and shows the relationship between the heat deterioration degree and the change amount of the heat deterioration degree for each temperature. An approximate expression 1 and a second approximate expression indicating the relationship between the amount of change in the degree of thermal deterioration and the temperature are obtained. That is, the heat deterioration characteristic calculation unit is a block that quantifies the heat deterioration degree and formulates it.

First, a method for quantifying the degree of thermal deterioration will be described.

The heat-degradable resin is colored by a heat load, as seen as a burn phenomenon. However, the visual judgment or the like can only make a judgment as to whether it is a clear colored state or a non-colored state, which is called discoloration.

Therefore, in the present invention, a sample having a known heat load temperature and time (preferably an initial color is white) is prepared by a heat load device such as a gear oven, and the amount of color change (color difference) of the sample is calculated. The color change (deterioration degree) of the uncolored region of the sample is quantified visually by measuring with a color difference meter or the like.

FIG. 9 is a graph showing an example of the heat deterioration characteristics of the resin quantified by this method. From this graph, the thermal deterioration limit value (coloring limit color difference) is determined. In the figure, YI = 22 is the thermal deterioration limit value.

Next, a method for formulating the degree of thermal deterioration will be described.

As can be seen from FIG. 9, the degree of thermal deterioration can be approximated to the first order with respect to time, and its approximate expression is shown as the expression (1).

[0021]

## EQU1 ## ΔYI (t) = k (T) × t + YI0 (1) where ΔYI: thermal deterioration degree (increment), k: thermal deterioration degree change amount, t: time, YI0: constant is there.

From the quantified heat deterioration characteristics of the resin, the constant YI0 and the heat deterioration degree change amount k (T) at each temperature are obtained.

FIG. 10 is a graph showing the relationship between the logarithm of the thermal deterioration degree change amount k obtained by the equation (1) and the reciprocal 1 / T of the temperature.

From the graph shown in FIG. 10, the relationship between the thermal deterioration degree change amount k and the temperature T is expressed by the equation (2).

[0025]

[Equation 2] k (T) = A × EXP (B / T) (2) Here, A and B are constants.

By obtaining the constants A and B, the thermal deterioration degree (increment) ΔYI is formulated as a function of the temperature T and the time t.

In the heat deterioration degree calculation unit, the heat deterioration degree change amount k is calculated from the equation (2) based on the temperature data of the heat history data obtained by the heat history calculation unit at a certain time, and the calculated heat is calculated. Based on the deterioration degree change amount k and the time data of the heat history data, the heat deterioration degree (increment) ΔYI is obtained from the equation (1). Then, the obtained thermal deterioration degree (increment) ΔYI
Is calculated using the equation (3) to calculate the heat deterioration degree YI up to the current calculation time.

[0028]

[Equation 3] By repeating the above calculation until the time t _end at which the temperature stabilizes, the final degree of thermal deterioration YI can be obtained.

The optimum mold designing unit judges whether the mold device is good or bad, by using the mold device data, the heat deterioration data of the final time obtained by the heat deterioration degree calculating unit, and the heat deterioration limit value as input data. , The thermal deterioration degree correlation data for the mold device parameters is calculated.

That is, when the value of YI obtained by the equation (3) exceeds the thermal deterioration limit value of 22, it is determined that the mold device is defective.

Further, the thermal history data during temperature raising and lowering is used as a parameter for factors such as mold device capacity, heat capacity, and thermal conductivity, which influence the history during temperature raising and lowering. The data is obtained, and the respective heat deterioration degrees are obtained by the heat deterioration degree quantifying method and the heat deterioration degree formulation method in the heat deterioration characteristic calculating section. Then, based on these data, parameters of the thermal deterioration degree (for example, capacity,
Function approximation of heat capacity and thermal conductivity (three levels) is performed to obtain a thermal deterioration contour line with each parameter as an axis.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an electrical configuration of a molding die design support system according to the present invention.

In the figure, the temperature and time obtained by the measurement and the output of the heat history calculation section 1 to which various data such as mold equipment data, resin physical property data, initial temperature data and cooling condition data are input are used as parameters. The outputs of the heat deterioration characteristic calculating unit 2 to which the heat deterioration characteristic data is input are given to the heat deterioration degree calculating unit 3, respectively.
The output of is configured to be guided to the optimum mold design unit 4.

The heat history calculation unit 1 calculates the heat history data during temperature increase / decrease, which is the temperature data of the mold and the resin at each time, based on the above input data.

The thermal deterioration characteristic calculation unit 2 uses the first approximate expression [Equation (1)] indicating the relationship between the thermal deterioration degree ΔYI and the thermal deterioration degree change amount k for each temperature, and the thermal deterioration degree change amount k. The second approximate expression [Expression (2)] showing the relationship between the temperature T and the temperature T is obtained.

The heat deterioration degree calculation unit 3 calculates the heat deterioration degree change amount from the second approximate expression [Equation (2)] based on the temperature data of the heat history data obtained by the heat history calculation unit 1 at a certain time. k
Based on the calculated thermal deterioration degree change amount k and the time data of the thermal history data, the first approximate expression [(1)
The heat deterioration degree (increment) ΔYI is calculated by the following equation. And
The thermal deterioration degree (increment) ΔYI thus obtained is integrated using the equation (3) to obtain the thermal deterioration degree YI up to the current calculation time.
To calculate. Further, by repeating this calculation until the time t _end at which the temperature stabilizes, the final thermal deterioration degree YI
To get.

The optimum mold designing unit 4 obtains the mold device data, the heat deterioration data of the final time obtained by the heat deterioration degree calculating unit 3 and the heat deterioration limit value as the respective input data, and obtains the formula (3). If the YI value exceeds the thermal deterioration limit value of 22, it is determined that the mold device is defective. Further, based on the heat deterioration degree data obtained by the heat deterioration characteristic calculating unit 3, a function approximation of the parameters of the heat deterioration degree (capacity, heat capacity, thermal conductivity in this embodiment) is performed, and heat is obtained with each parameter as an axis. It is designed to obtain a deterioration contour line.

Next, an example of parameter design using the design support system having the above configuration will be shown.

First, in the heat deterioration characteristic calculation unit 2, the resin heat deterioration characteristic data is measured by the above-described heat deterioration degree quantification method. It is assumed that the measurement results are shown in FIGS. 9 and 10. Then, the thermal deterioration limit value is determined as 22 from the graph shown in FIG.

From the heat deterioration characteristic data shown in FIG.
The constants A and B in the equation (2) are calculated.

On the other hand, the mold history data of the mold and the resin is calculated by inputting the mold apparatus data, the resin physical property data, the initial temperature data, and the cooling condition data to the heat history calculation unit 1.

Here, in the present embodiment, the shape of the mold device is the shape shown in FIG. 2 (reference numeral 7 in the drawing is a resin flow path),
The heating / cooling conditions are the conditions shown in FIG. 3, and the mold device design parameters are the conditions shown in FIG. The thermal history data obtained under these conditions are shown in FIGS. 5 and 6. FIG. 5 shows heat history data at the time of temperature rise, and FIG. 6 shows heat history data at the time of temperature decrease.

Next, the heat history data (FIGS. 5 and 6) obtained by the heat history calculation unit 1, the constants A and B obtained by the heat deterioration characteristic calculation unit 2, and the heat deterioration degree limit value ( YI = 2
2) and are input to the heat deterioration degree calculation unit 3 to calculate the heat deterioration degree under each condition. Then, the quality is judged by comparing the calculated thermal deterioration degree under each condition with the thermal deterioration limit value. An example of this determination result is shown in FIG.

Next, the determination result (FIG. 7) obtained by the thermal deterioration degree calculation unit 3 and the design parameter (FIG. 4) are input to the optimum mold design unit 4. The optimum mold design unit 4 creates and outputs a contour line of the degree of thermal deterioration for the given design parameter (see FIG. 8).

Then, the mold design is examined using the contour lines shown in FIG. That is, it is assumed that a mold material having a thermal conductivity of 100 W / m · K is selected. Here, since the thermal deterioration limit value is 22, if the thermal deterioration limit value is 20 in consideration of safety, the pass region is the hatched portion in FIG. 8. From this, it is understood that the mold thickness D must be designed to be 45 mm or less.

[0047]

According to the molding die design method and the design support system of the present invention, the thermal history of the unsteady process in which thermal degradation is most likely to occur in the resin is predicted, and the thermal history is predicted. Since the configuration is used as the use data, it is possible to perform the prediction of the deterioration degree of the heat-deteriorated resin, the quality judgment, and the parameter design before the mold is made. Therefore, it is possible to reduce the time loss and the cost loss due to the structure at the time of mold development, the condition change.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a molding die design support system according to the present invention.

FIG. 2 is a diagram showing an example of a die device shape.

FIG. 3 is a chart showing an example of cooling and heating conditions.

FIG. 4 is a chart showing an example of design parameters.

FIG. 5 is a graph showing an example of thermal history data during temperature rise.

FIG. 6 is a graph showing an example of thermal history data during temperature reduction.

FIG. 7 is a chart showing a calculation result of a thermal deterioration degree.

FIG. 8 is a diagram showing a correlation between a mold device design parameter and a thermal deterioration degree.

FIG. 9 is a graph showing an example of heat deterioration characteristic data of resin.

FIG. 10 is a graph showing the relationship between the amount of change in thermal deterioration and temperature.

[Explanation of symbols]

1 Heat history calculator 2 Thermal deterioration characteristic calculation unit 3 Thermal deterioration degree calculation unit 4 Optimal mold design department

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-148062 (JP, A) JP-A-5-329905 (JP, A) JP-A-5-329903 (JP, A) JP-A-5- 189526 (JP, A) JP 4-345818 (JP, A) JP 4-331125 (JP, A) JP 60-252251 (JP, A) JP 7-214629 (JP, A) JP-A-6-344368 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/76 B29C 33/38 B29C 45/78 G06F 17/50

Claims (2)

(57) [Claims] 1. Thermal history data during temperature increase / decrease, which is temperature data of mold and resin at respective times, is calculated based on various data such as mold device data, resin physical property data, initial temperature data, and cooling condition data. On the other hand, based on the heat deterioration characteristic data obtained by the measurement using temperature and time as parameters, the first approximation formula showing the relationship between the heat deterioration degree and the heat deterioration degree change amount for each temperature, and the heat deterioration degree. A second approximate expression indicating the relationship between the amount of change and the temperature is obtained, the amount of change in the degree of thermal deterioration is calculated from the second approximate expression based on the temperature data of the thermal history data at a certain time, and the calculated heat is calculated. The heat deterioration degree is calculated from the first approximate expression based on the deterioration degree change amount and the time data of the heat history data, and the heat deterioration degree up to the current calculation time is calculated by integrating the heat deterioration degree. Repeat until the final time and heat at each time Deterioration degree is calculated, then, based on the mold device data, the heat deterioration data of the final time and the heat deterioration limit value, the quality of the mold device is determined, and the heat deterioration degree correlation data for the mold device parameters. A method for designing a molding die, which comprises: 2. Thermal history data during temperature rising / falling, which is temperature data of mold and resin at each time, is calculated by using various data such as mold device data, resin physical property data, initial temperature data, and cooling condition data as input data. A heat history calculation unit that performs the above, and a first approximation that indicates the relationship between the degree of thermal deterioration and the amount of change in the degree of thermal deterioration for each temperature, using the thermal deterioration characteristic data obtained by measurement as parameters as the thermal deterioration characteristic data. And a heat deterioration characteristic calculation unit that obtains a second approximate expression indicating the relationship between the amount of change in heat deterioration degree and temperature, and based on temperature data of the heat history data obtained by the heat history calculation unit at a certain time. A thermal deterioration degree change amount is calculated from the second approximate expression, and a thermal deterioration degree is calculated from the first approximate expression based on the calculated thermal deterioration degree change amount and the time data of the thermal history data, By accumulating this
It was obtained by the heat deterioration degree calculation unit that calculates the heat deterioration degree up to the current calculation time and repeats this until the final time to calculate the heat deterioration degree at each time, the mold device data, and the heat deterioration degree calculation unit. An optimum mold designing unit was provided which, using the heat deterioration data of the final time and the heat deterioration limit value as input data, determines the quality of the mold device and calculates the heat deterioration degree correlation data for the mold device parameters. A design support system for molding dies.