JPH05189526A - Drift analysis/evaluation system for injection molding metallic mold - Google Patents

Abstract

PURPOSE:To provide a drift analysis/evaluation system for injection molding metallic mold in order to evaluate the gate size or the runner size for prevention of the burning caused by the injection molding. CONSTITUTION:The resin pack analysis is carried out with the resin flow velocity, the gate diameter and the number of gates defined as the parameters or the resin flow rate, the runner length, the runner diameter and the number of runners defined as the parameter respectively. Thus the distributions of the pressure, the temperatures, etc., are calculated by a fill analyzing part 11. An index calculating part 12 calculates the index value to show the burning for each number of gates with a fixed resin flow rate or the index value showing the burning for each number of runners with a fixed resin flow rate and the fixed runner length and also decides a combination to attain the value expecting a safety rate from the occurring limit of the burning based on the index value calculated for each parameter. Then a display part 13 shows the relation of the parameters attaining each of attained combinations in a graph.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow analysis and evaluation system for an injection molding die for evaluating a gate dimension or a runner dimension for preventing burnout which is a defective appearance occurring during injection molding.

[0002]

2. Description of the Related Art In the field of injection molding, when a mold for a new product is raised, the mold is designed by relying on the empirical know-how of the designer.

That is, the gate diameter is determined by the empirical rule regardless of the resin flow rate and the number of gate points at the time of filling, and the runner diameter is determined by the empirical rule regardless of the resin flow rate and the runner length. For this reason, temporary die punching is performed using the designed die, and when problems such as burnout or deformation occur at that point, the gate diameter and runner diameter are re-examined for the first time, and the die is reworked and provisional die firing is performed again. One new product was being developed through the process of performing.

[0004]

As described above, in the conventional die design, not only variations in the die designed by the experience of the designer occur but also quantitative evaluation based on scientific calculation can be performed. Since there is no such value, the applicable range of the determined numerical value is also limited, and there is a problem that even if it is applied to a new field, it is hardly applicable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flow analysis evaluation system for an injection molding die which enables quantitative evaluation based on scientific calculation. ..

[0006]

In order to solve the above problems, a flow analysis evaluation system for an injection molding die according to the present invention sets a gate size for preventing burnout which is a defective appearance that occurs during injection molding. A system for evaluation,
The resin flow rate, gate diameter, and number of gate points are used as parameters to perform resin filling analysis, and the filling analysis unit that calculates the distribution of pressure, temperature, etc., and the resin flow rate is kept constant based on the analysis results of this filling analysis unit. While calculating the index value that represents the burn for each gate score, based on the calculated index value for each parameter, the index calculation unit that finds a combination that achieves a value that anticipates a safety factor from the burn limit, A relationship is provided for each parameter that achieves each combination calculated by the index calculation unit, and a display unit that displays a graph for each number of gate points.

A flow analysis evaluation system for an injection molding die according to the present invention is a system for evaluating a runner dimension for preventing burnout which is a defective appearance that occurs during injection molding. Length, runner diameter,
By performing a resin filling analysis using the number of runners as each parameter, the filling analysis unit that calculates the distribution of pressure, temperature, etc., and the resin flow rate (filling time) and the runner length are calculated based on the analysis results of this filling analysis unit. With an index calculation unit that calculates the index value that represents the burn for each number of runners as a constant, and an index calculation unit that calculates a combination that achieves a value that anticipates a safety factor from the occurrence limit of the burn based on the calculated index value for each parameter And a display unit that graphically displays the relationship of each parameter that achieves each combination obtained by the index calculation unit for each number of runners.

[0008]

[Function] Regarding the relationship between the flow rate, the gate diameter, the number of gate points, and the burn, which are related to the poor appearance, it is generally easy to burn when the resin flow rate (flow velocity) is large, difficult to burn when the gate diameter is large, and difficult to burn when the number of gate is large. Is said. Therefore, the distribution of pressure, temperature, etc. is calculated by performing the resin filling analysis in the filling analysis unit using these conditions, that is, the resin flow rate, the gate diameter, and the number of gate points as parameters.
After that, the index calculation unit calculates the index value representing the burn for each gate point based on the analysis result while keeping the resin flow rate constant. Then, based on the calculated index value for each parameter, find a combination that achieves a value that anticipates a safety factor from the limit of occurrence of burn, and display the relationship of each parameter that achieves this combination for each gate score in a graph. ..
That is, when two of the three parameters are determined, the remaining one parameter can be automatically determined.

Further, regarding the relationship between resin flow rate, runner length, runner diameter, number of runners and burnout relating to poor appearance, it is generally easy to burn when the resin flow rate (flow velocity) is high and easy to burn when the runner length is long. It is said that if the diameter is large, it is difficult to burn, and if the number of runners is large, it is difficult to burn.
Therefore, these conditions, that is, resin flow rate, runner length, runner diameter, and number of runners are used as parameters.
By performing the resin filling analysis in the filling analysis unit, the distribution of pressure, temperature, etc. is calculated. After that, the index calculation unit calculates the index value representing the burn for each number of runners, with the resin flow rate (filling time) and the runner length being constant, based on the analysis result. Then, based on the calculated index value for each parameter, find a combination that achieves a value that anticipates a safety factor from the limit of burn occurrence, and display the relationship of each parameter that achieves this combination for each number of runners. .. That is, by determining three parameters out of four parameters, it becomes possible to automatically determine the remaining one parameter.

[0010]

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 the electrical construction of a flow analysis and evaluation system for an injection molding die according to the present invention.

In the figure, the output of the filling analysis section 11 for performing resin filling analysis with the resin flow rate, the gate diameter, the number of gates, the runner length, the runner diameter, the number of runners, etc. as parameters is set for each gate point with the resin flow rate being constant. An index calculation unit 12 that calculates an index value representing the burn for each runner score
The output of the index calculation unit 12 is guided to the filling analysis unit 11 and the display unit 13.

The filling analysis unit 11 receives as input data,
Molding condition data, product shape data, and resin physical property data are given. Here, the molding condition data is data such as filling time (injection rate), holding pressure, holding time, mold temperature distribution, and injection resin temperature, and the resin physical property data is viscosity, density, Thermal properties (heat conductivity, specific heat, solidification temperature,
Crystallization heat).

Next, the operation of the flow analysis evaluation system having the above configuration will be described separately for (1) when evaluating the gate dimension and (2) when evaluating the runner dimension.

(1) To evaluate the gate size.

FIG. 2 shows an operation flow chart in the case of evaluating the gate dimension, which will be described below with reference to this flow chart.

First, the designer sets the resin flow rate (flow velocity) Q, the gate diameter R, and the number of gate points n in the filling analysis unit 11 (step S1). After that, the filling analysis unit 11 performs the filling analysis based on the input data such as the given molding condition data, product shape data, and resin physical property data (steps S2 and S3). For example, a vinyl chloride resin is used as a resin, a resin temperature is 205 degrees as a molding condition, and a mold temperature is 5
Input each data such as 5 degrees.

In the filling analysis here, the flow field in each state is assumed to be a Hell-Shaw flow and solved using the finite element method to calculate the distribution of pressure, temperature and the like. Since this calculation method is the same as the conventional one, detailed description thereof is omitted here.

The index calculation unit 12 processes the analysis result obtained by the filling analysis unit 11 to obtain an index value representing a burn which is a defective appearance at the time of injection molding by the following formula (step S4).

[0020]

[Equation 1]

However, A, B: constants, T: temperature, t: time, based on the index value obtained by this equation, it is predicted whether or not burns will occur under the current input conditions (resin flow rate, gate diameter, number of gate points). To be done.

The filling analysis section 11 and the index calculation section 12 arbitrarily change the value of each parameter and repeat steps S2 to S4 (step S7). That is, if the degree of freedom of each parameter is N, the series of steps S2 to S4 is repeated 3 ^N times. Then, the presence / absence of the occurrence of burning in each condition thus obtained and the index value are stored in a storage unit (not shown).

When the analysis and index value calculation under all the conditions are completed, the index calculation unit 12 finally finds a combination in which no burn occurs among the combinations of the parameters. That is, a safety factor (for example,
80%) to obtain an index value that clears the burn limit (step S5). Fig. 3 shows the flow rate Q
The figure shows an evaluation chart for the burnout limit of the gate diameter when the gate diameter is constant.

The display unit 13 graphically displays the relationship of each parameter for clearing the limit of occurrence of burn-off obtained by the index calculation unit 12 in this manner for each gate point. In each curve diagram shown in FIG. 4, the vertical axis represents the gate diameter R and the horizontal axis represents the flow rate Q.
The relationship for each number of gate points is shown.

Therefore, if the filling time is obtained from the entire cycle, the number of gate points is determined due to the limitation of product design, and the runner length is also determined at the same time, the gate diameter is automatically determined from FIG. Further, if the gate diameter is determined from the releasability of the gate, the number of moldable gate points is determined.

(2) When evaluating runner dimensions.

FIG. 5 shows an operation flow chart in the case of evaluating the runner size, which will be described below with reference to this flow chart.

First, the designer sets the resin flow rate (flow velocity) Q, runner length L, runner diameter R, and number of runners n in the filling analysis unit 11 (step S11). After this,
The filling analysis unit 11 performs the filling analysis based on the input data such as the given molding condition data, product shape data, and resin physical property data (steps S12 and S13). For example, vinyl chloride resin is used as the resin to be used, resin temperature of 205 ° and molding temperature of 55 ° are input as molding conditions.

In the filling analysis here, the flow field in each state is assumed to be the Hell-Shaw flow, and the solution is solved using the finite element method to calculate the distribution of pressure, temperature and the like. Since this calculation method is the same as the conventional one, detailed description thereof is omitted here.

The index calculation unit 12 processes the analysis result obtained by the filling analysis unit 11 to obtain an index value representing a burn which is a defective appearance at the time of injection molding by the following formula (step S4).

[0031]

[Equation 2]

However, A, B: constants, T: temperature, t: time, based on the index value obtained by this formula, the current input conditions (resin flow rate, runner length, runner diameter, number of runners)
The occurrence of burns is predicted.

The filling analysis unit 11 and the index calculation unit 12 arbitrarily change the value of each parameter and repeat Steps S2 to S4 (Step S17). That is, if the degree of freedom of each parameter is N, the above steps S2 to
The series of steps S4 is repeated 4 ^N times. Then, the presence / absence of the occurrence of burning in each condition thus obtained and the index value are stored in a storage unit (not shown).

When the analysis and index value calculation under all the conditions are completed, the index calculation unit 12 finally finds a combination in which no burn occurs among the combinations of the parameters. That is, a safety factor (for example,
80%) is applied to obtain an index value that clears the burn occurrence limit (step S15). FIG. 6 shows a burn-off limit evaluation chart of the runner diameter when the number of runners is 1, and the flow rate is constant and the runner length L is constant.

The display unit 13 graphically displays the relationship of each parameter for clearing the occurrence limit of burn-out obtained by the index calculation unit 12 in this manner for each flow rate. Each curve diagram shown in FIG. 7 shows the relationship for each flow rate, where the vertical axis represents the runner diameter R and the horizontal axis represents the runner length L.

Therefore, if the filling time (flow rate) is obtained from the entire cycle, the number of runners is determined due to the product design limitation, and at the same time the runner length is determined, the runner diameter is automatically determined from FIG.

[0037]

The flow analysis and evaluation system for the injection molding die according to the present invention uses the resin flow rate, the gate diameter, and the number of gate points as parameters, or the resin flow rate, the runner length, the runner diameter, and the number of runners as the parameters. By performing a resin filling analysis, a filling analysis unit that calculates the distribution of pressure, temperature, etc., and based on the analysis result, calculation of an index value that represents the burn for each gate point with the resin flow rate kept constant,
Alternatively, the resin flow rate and the runner length are kept constant, and the index value representing the burn for each number of runners is calculated, and based on the calculated index value for each parameter, a value that allows for a safety factor from the burn limit is achieved. Since the configuration is provided with an index calculation unit that obtains a combination to be obtained and a display unit that graphically displays the relationship of each parameter that achieves each obtained combination, 3 parameters or 4 that does not cause burns
Since the solution of the combination of parameters can be seen at a glance,
You can always perform quantitative evaluation in product design,
It is possible to prevent the conventional variation in the evaluation, the variation in the determination method, and the like. In addition, since quantitative evaluation can be performed, the number of times of mold modification can be reduced, and as a result, the development period of one product can be significantly shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a flow analysis evaluation system for an injection mold according to the present invention.

FIG. 2 is a flowchart for explaining an operation when evaluating a gate dimension.

FIG. 3 is a diagram for evaluating a gate diameter burnout limit.

FIG. 4 is an evaluation diagram of gate dimensions.

FIG. 5 is a flowchart for explaining an operation when evaluating runner dimensions.

FIG. 6 is a graph for evaluating the runner diameter burnout limit.

FIG. 7 is an evaluation diagram of runner dimensions.

[Explanation of symbols]

 11 Filling analysis unit 12 Index calculation unit 13 Display unit

Claims (2)

[Claims] 1. A system for evaluating a gate dimension for preventing burnout, which is a defective appearance that occurs at the time of injection molding, by performing a resin filling analysis by using a resin flow rate, a gate diameter, and a number of gate points as parameters. Based on the filling analysis unit that calculates the distribution of pressure, temperature, etc., and based on the analysis results from this filling analysis unit, the index value that represents the burn for each gate point is calculated with the resin flow rate kept constant, and the calculated parameters are calculated. Based on each index value, the relationship between the index calculation unit that finds a combination that achieves a value that anticipates a safety factor from the burn limit and each parameter that achieves each combination obtained by this index calculation unit A flow analysis and evaluation system for injection molding dies, comprising: a display unit for displaying a graph for each. 2. A system for evaluating a runner dimension for preventing burnout, which is a defective appearance that occurs during injection molding, and a resin filling analysis is performed using a resin flow rate, a runner length, a runner diameter, and the number of runners as parameters. Therefore, based on the filling analysis unit that calculates the distribution of pressure, temperature, etc., and based on the analysis results of this filling analysis unit, the resin flow rate (filling time) and the runner length are constant, and the index value that represents the burn for each runner And an index calculation unit that calculates a combination that achieves a value that anticipates a safety factor from the limit of occurrence of burn based on the calculated index value for each parameter, and each combination calculated by this index calculation unit. The flow analysis of the injection mold is provided with a display unit for displaying the relationship of each parameter that achieves Evaluation system.