JP3236069B2 - Flow analysis evaluation system for injection molds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow analysis of an injection molding die for evaluating the size of a resin flow path from an injection molding machine to a die in order to prevent the appearance failure during the injection molding. Regarding the evaluation system.

[0002]

2. Description of the Related Art In the field of injection molding, when a mold for a new product is produced, the design of the mold has been performed by relying on the empirical know-how of a designer.

That is, the gate diameter is determined by an 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 an empirical rule regardless of the resin flow rate and the runner length. For this reason, temporary tacking is performed with the designed mold, and when problems such as burnout or deformation occur at that point, the gate diameter and runner diameter etc. are reviewed for the first time, the mold is reworked, and temporary tacking is performed again One new product has been developed through such a process.

[0004]

As described above, in the conventional mold design, not only does the mold designed by the experience of the designer vary, but also a quantitative evaluation based on scientific calculations can be performed. Therefore, the range of application of the determined numerical value is 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 and evaluation system for an injection mold which enables quantitative evaluation based on scientific calculations. .

[0006]

In order to solve the above-mentioned problems, a flow analysis and evaluation system for an injection mold according to the present invention is provided. A system for evaluating the size of a resin flow path from a molding machine to a mold, wherein the resin flow path is constituted by sprue, runner, and gate portions in order from the injection molding machine side, a sprue diameter, a runner diameter. , Game
By performing resin filling analysis preparative size as each of the parameters, pressure, and filling analysis unit for calculating a distribution of the temperature, based on an analysis result in the filling analyzer, the sprue diameter, runner diameter, the gate diameter An index calculation unit that calculates the index value of each part under the initial conditions, and based on the initial analysis result by this index calculation unit, calculates a change in the index value of the part by changing the sprue diameter, A sprue diameter index determining unit that determines an appropriate index value in which the amount of change is equal to or less than a predetermined amount and replaces the index value of the sprue part of the initial analysis result, based on the analysis result in which the index value is replaced by the sprue diameter index determining unit. Then, a change in the index value of the part due to the change in the runner diameter is calculated, an appropriate index value in which the amount of change is equal to or less than a predetermined amount is determined, and the index value of the runner portion of the analysis result is substituted. Based on the runner diameter index determining unit to be replaced and the analysis result in which the index value has been replaced by the runner diameter index determining unit, a change in the index value of the part by subsequently changing the gate diameter is calculated, and the change amount A gate diameter index determining unit that determines an aptitude index value that is equal to or less than a predetermined amount and replaces the index value of the gate unit of the analysis result, and a display that graphically displays the aptitude index value of each part obtained by each index determining unit And a part.

[0007]

The relationship between sprue diameter, runner diameter, gate diameter and burn in relation to poor appearance is generally said to be as large as each diameter is large. Therefore, if the diameter is increased in each part, the burn index ( for example, the maximum resin temperature)
[Hereinafter referred to as “maximum temperature”) ) can be reduced. However, if each diameter is excessively large, not only will each part fail to perform its function, but also waste of raw material costs will occur. Therefore, a point at which the rate of decrease of the index value begins to slow down when the diameters are increased is defined as the design dimension of the portion. Here, the temperature rise in the flow in the cylinder is proportional to the fourth power of the radius.

That is, in the filling analysis section, the sprue diameter,
Runner diameter, by performing resin filling analysis gate size as the parameters to calculate the pressure, the distribution of temperature.

The index calculating section calculates an index value ( for example, maximum temperature) of each part under the initial conditions of the sprue diameter, the runner diameter, and the gate diameter based on the analysis result of the filling analyzing section.

Thereafter, based on the results of the initial analysis, the suitability index values are sequentially calculated in the order from the injection molding machine side to the mold side.

That is, the sprue diameter index determination unit calculates a change in the index value of the part when the sprue diameter is arbitrarily changed based on the initial analysis result by the index calculation unit, and the change amount is a predetermined amount ( This predetermined amount is set in advance to a level that hardly changes) and an aptitude index value that is less than or equal to is obtained and replaced with the index value of the sprue part of the initial analysis result.

The runner diameter index determining unit calculates a change in the index value of the part when the runner diameter is changed next based on the analysis result in which the index value is replaced by the sprue diameter index determining unit. An aptitude index value at which the amount of change is equal to or less than a predetermined amount (this predetermined amount is also preset to a level that hardly changes) is obtained and replaced with the index value of the runner part of the analysis result.

The gate diameter index determining section calculates a change in the index value of the portion when the gate diameter is changed next based on the analysis result in which the index value is replaced by the runner diameter index determining section. An aptitude index value at which the amount of change is equal to or less than a predetermined amount (this predetermined amount is also set in advance to a level that hardly changes) is obtained, and is replaced with the index value of the gate part of the analysis result. Then, the suitability index values of the respective parts thus replaced are graphically displayed on the display unit.

As described above, as a result of replacing each part with the suitability index value, an appropriate dimension in which the temperature rise is suppressed most in each part of the sprue, the runner, and the gate is determined.

[0015]

An embodiment of the present invention will be described below with reference to the drawings.

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

In the figure, sprue diameter, runner diameter,
With the diameter of the sheet as each parameter, the set resin flow rate and
The output of the filling analysis unit 11 that performs resin filling analysis based on the length of the runner, the length of the runner, the gate length, etc. is based on the analysis result of the filling analysis unit 11 under the initial conditions of the sprue diameter, the runner diameter, and the gate diameter. The index calculation unit 12 calculates the index value of each part. The output of the index calculation unit 12 is:
A change in the index value of the part when the sprue diameter, the runner diameter, and the gate diameter are arbitrarily changed is calculated, and the change amount is a predetermined amount (this predetermined amount is preset to a level that hardly changes). The following suitability index values are obtained and led to the index determining unit 13 for replacing the index values of the respective parts in the initial analysis result. The output of the index determining unit 13 is led to the filling analyzing unit 11 and the display unit 14. Configuration.

In the filling analysis unit 11, as input data,
Molding condition data, product shape data, and resin physical property data are given. Here, molding condition data refers to data such as filling time (injection rate), dwell pressure, dwell time, mold temperature distribution, injected resin temperature, and the like. Resin physical property data includes viscosity, density, Thermal properties (thermal conductivity, specific heat, solidification temperature,
Heat of crystallization).

Although not shown, the index judging section 13 comprises a sprue diameter index judging section 131, a runner diameter index judging section 132, a second sprue diameter index judging section 133, and a gate diameter index judging section 134. Have been.

Next, the operation of the flow analysis evaluation system having the above configuration will be described.

However, in this embodiment, the resin flow path from the injection molding machine to the mold is constituted by a sprue, a runner, a second sprue, and a gate. FIG. 2 shows an operation flowchart for evaluating the dimensions of the resin flow path, and the description will be made with reference to this flowchart.

First, the designer sets each value of the resin flow rate (flow velocity) Q, the gate diameter R, and the number n of gates in the filling analysis unit 11 (step S1). Thereafter, the filling analysis unit 11 performs a filling analysis based on the input data such as the given molding condition data, product shape data, and resin property data (Steps S2 and S3). For example, the shape model of the molded product is a shape shown in FIG. 3, and a vinyl chloride resin is used as a resin to be used. Further, as the molding conditions, the injection flow rate 100
cm ³ / sec, injection time ³ sec, injection resin temperature 205 °, mold temperature 55 °, maximum injection time 15 sec, limit injection pressure 1
Inputting each data, such as 500 kg / cm ^2. Also, sprue,
The initial values of the dimensions of the runner and the gate are set to the values in the table shown in FIG. That is, the number of gate points is one point gate,
The sprue diameter is 3 mm on the resin inflow side and 8 mm on the resin outflow side. The runner diameter is 6 mm. The second sprue diameter is 8 mm on the resin inflow side and 3 mm on the resin outflow side. The gate diameter is 2 mm. Shape. However, each diameter is a diameter.

[0023] In filling the analysis here, a flow field in each state assuming Hell-Shaw flow, solved using the finite element method, calculating the pressure, the distribution of temperature. Since this calculation method is the same as the conventional one, a detailed description is omitted here.

The index calculation unit 12 processes the analysis result obtained by the filling analysis unit 11 to obtain an index value (for example, a maximum temperature ) indicating a burn which is a defective appearance during injection molding.
Degrees) the required Mel (step S4). The index value is
In addition to the maximum temperature, it can be obtained by the following equation.

[0025]

(Equation 1)

However, A, B: constant, T: temperature, t: time Based on the index value obtained in step S4, the occurrence state of the burn under the current input condition is predicted. This index value is displayed on the display unit 14 via the index determination unit 13.

FIG. 5 shows the initial analysis results when the sprue, runner, and gate dimensions are set to the above-mentioned initial values. The vertical axis represents the maximum temperature as an index value, and the horizontal axis represents the injection molding machine. The distance from the injection part is respectively taken. In the figure, the maximum temperature of 350 ° C. is the burn limit temperature, and this temperature is a value already known depending on the resin. The results of this initial analysis show that 300
After passing through the runner part and the second sprue part in a high temperature state within the range of 300 to 350 degrees, it is injected into the gate part, exceeding the limit temperature of 350 degrees, and Will be filled.

Based on the result of the initial analysis, the index determination unit 13 first compares the change amount of the current index value with the previous change amount of the index value in the sprue diameter index determination unit 131 (step S5). . However, in this case,
Since there is no change amount data in both cases, the sprue diameter index determining unit 131 advances the operation to step S9 to set the sprue diameter to a constant width (this constant width is set in advance, for example, 0.5 mm). Then, the processing of steps S2 to S4 is performed using the sprue diameter, and a new index value (referred to as a first index value) of the sprue portion is calculated.
The sprue diameter index determining unit 131 obtains a difference between the first index value and the previous index value (initial index value), and stores the difference as a current change amount (this is referred to as a second change amount).

Next, the sprue diameter index determining unit 131 advances the operation to step S9 again to increase the sprue diameter by a certain width, performs the processing of the above steps S2 to S4 with the sprue diameter, and newly executes the processing of the sprue part. Calculation of an appropriate index value (referred to as a second index value). The sprue diameter index determining unit 131 calculates a difference between the second index value and the previous first index value, and stores the difference as a current change amount (referred to as a second change amount).

Thereafter, the sprue diameter index determining unit 131
A comparison is made between the current change amount (ie, the second change amount) and the previous change amount (ie, the first change amount), and the difference between the change amounts is equal to or smaller than a predetermined amount (this predetermined amount is almost equal to the change amount). (Predetermined to a level not to perform).

The sprue diameter index determining unit 131 repeats the above operation, and when the difference between the current change amount and the previous change amount is equal to or less than a predetermined amount, the sprue diameter index value at that time is set to the suitability index. It is stored as a value and replaced with the index value of the sprue part of the initial analysis result.

FIG. 6 shows a process in the sprue diameter index determining unit 131, that is, a change in the index value due to an increase in the sprue diameter. In this figure, the curve of the index value plotted by a square shows the case where the difference between the current change amount and the previous change amount is equal to or smaller than a predetermined amount, and this index value is set as the appropriate index value.

After the suitability index value of the sprue portion is determined in this way, the index determination unit 13 first determines the runner diameter index determination unit 132 based on the analysis result obtained by replacing the index value of the sprue portion. Then, the change amount of the current index value is compared with the change amount of the previous index value (step S6).
However, in this case, since there is no data of the amount of change both in the previous time and this time, the runner diameter index determination unit 132
The operation proceeds to step S9 to increase the runner diameter by a constant width (this constant width is set in advance and is, for example, 0.5 mm), and the processes of steps S2 to S4 are performed using the runner diameter. A new index value (referred to as a first index value) of the runner section is calculated. The runner diameter index determining unit 132 obtains a difference between the first index value and the previous index value (initial index value), and stores the difference as a current change amount (this is referred to as a second change amount).

Next, the runner diameter index judging section 132 advances the operation to step S9 again to increase the runner diameter by a certain width, and uses the runner diameter to execute the above steps S2 to S9.
4 is performed to calculate a new index value of the runner section (referred to as a second index value). Runner diameter index determination unit 13
In step 2, the difference between the second index value and the previous first index value is obtained, and this difference is stored as the current change amount (referred to as a second change amount).

Thereafter, the runner diameter index determining unit 132 compares the current change amount (ie, the second change amount) with the previous change amount (ie, the first change amount), and compares the change amount. It is determined whether or not the difference is equal to or less than a predetermined amount (this predetermined amount is preset to a level that hardly changes).

The runner diameter index determining section 132 repeats the above operation, and when the difference between the current change amount and the previous change amount is equal to or smaller than a predetermined amount, the runner diameter index value at that time is set to the suitability index. While memorizing as a value,
The suitability index value is replaced with the index value of the runner part of the analysis result obtained by replacing the index value of the sprue part.

FIG. 7 shows a process in the runner diameter index determining section 132, that is, a change in the index value due to an increase in the runner diameter. However, FIG. 7 also shows a change in the index value caused by enlarging the diameter of the second sprue described below. In this figure, the curve of the index value plotted by a square shows the case where the difference between the current change amount and the previous change amount is equal to or smaller than a predetermined amount, and this index value is set as the appropriate index value.

When the suitability index value of the runner section is determined in this way, the index determination section 13 first determines the second sprue diameter based on the analysis result obtained by replacing the index values of the sprue section and the runner section. The index determining unit 133 compares the current index value change amount with the previous index value change amount (step S7). However, in this case, since there is no data on the amount of change both in the previous time and in the present time, the second sprue diameter index determining unit 133 advances the operation to step S9 to set the second sprue diameter to a constant width (this constant width is (It is set in advance, for example, 0.5 mm).
The processing of steps S2 to S4 is performed using the sprue diameter, and a new index value (referred to as a first index value) of the second sprue unit is calculated. The second sprue diameter index determining unit 133 obtains the difference between the first index value and the previous index value (initial index value) and stores the difference as the current change amount (this is referred to as a second change amount). I do.

Next, the second sprue diameter index judging unit 133 advances the operation to step S9 again to increase the second sprue diameter by a certain width, and uses the second sprue diameter to execute step S9.
The processing of 2 to S4 is performed to calculate a new index value of the second sprue unit (referred to as a second index value). The second sprue diameter index determining unit 133 obtains a difference between the second index value and the previous first index value, and stores the difference as a current change amount (referred to as a second change amount).

Thereafter, the second sprue diameter index judging unit 133 compares the current change amount (ie, the second change amount) with the previous change amount (ie, the first change amount). It is determined whether or not the difference between the amounts of change is equal to or less than a predetermined amount (this predetermined amount is preset to a level that hardly changes).

The second sprue diameter index judging unit 133 repeats the above operation, and when the difference between the current change amount and the previous change amount becomes equal to or smaller than a predetermined amount, the index at the second sprue diameter set at that time. The value is stored as the suitability index value, and the suitability index value is replaced with the index value of the second sprue part of the analysis result in which the index values of the sprue unit and the runner unit have been replaced.

FIG. 7 shows a process in the second sprue diameter index determining unit 133, that is, a change in the index value due to the enlargement of the second sprue diameter. In this figure, the curve of the index value plotted by a square shows the case where the difference between the current change amount and the previous change amount is equal to or less than a predetermined amount,
This index value is used as the suitability index value.

When the suitability index value of the second sprue unit is determined in this way, the index judgment unit 13 next determines the sprue unit,
First, based on the analysis result in which the index values of the runner section and the second sprue section are replaced, the gate diameter index determining section 134 compares the change amount of the current index value with the change amount of the previous index value (step). S8). However, in this case, since there is no data on the amount of change both last time and this time,
The gate diameter index determining unit 134 advances the operation to step S9 to increase the gate diameter by a certain width, performs the processing of steps S2 to S4 with the gate diameter, and obtains a new index value of the gate unit (the first index value). Is calculated.)
The gate diameter index determination unit 134 obtains a difference between the first index value and the previous index value (initial index value), and stores the difference as a current change amount (this is referred to as a second change amount).

Next, the gate diameter index judging section 134 advances the operation to step S9 again to increase the gate diameter by a certain width, performs the processing of steps S2 to S4 with the gate diameter, and newly executes the processing of the gate section. Calculation of an appropriate index value (referred to as a second index value). The gate diameter index determining unit 134 calculates a difference between the second index value and the previous first index value, and stores the difference as a current change amount (referred to as a second change amount).

Thereafter, the gate diameter index determining section 134 determines
A comparison is made between the current change amount (ie, the second change amount) and the previous change amount (ie, the first change amount), and the difference between the change amounts is equal to or smaller than a predetermined amount (this predetermined amount is almost equal to the change amount). (Predetermined to a level not to perform).

When the difference between the current change amount and the previous change amount is equal to or smaller than a predetermined amount, the gate diameter index determining unit 134 determines the index value at the gate diameter set at that time as the suitability index. The appropriate index value is stored as a value, and the appropriate index value is replaced with the index value of the gate part of the analysis result obtained by replacing the index values of the sprue unit, the runner unit, and the second sprue unit.

FIG. 8 shows a process in the gate diameter index determining section 134, that is, a change in the index value due to the enlargement of the gate diameter. In this figure, the curve of the index value plotted with diamonds indicates when the difference between the current change amount and the previous change amount is equal to or smaller than a predetermined amount, and this index value is set as the appropriate index value.

[0048] As described above, the final <br/>-format Dan'yui results of each index determination unit is outputted to the display unit 14, the display unit 14, the sprue portion is the final decision result, the runner portion, the 2 The appropriateness index values of the sprue portion and the gate portion are displayed in a graph. FIG.
Is a graph showing the final judgment result.

The display unit 14 displays the size of each part corresponding to the suitability index value. FIG. 10 shows the finally determined diameter of each part. In this embodiment, the sprue diameter is changed from 3-8 mm to 5-10 mm, and the runner diameter is set to 6 mm.
To 8 mm, the second sprue diameter from 8-3 mm to 9-4 mm,
It can be seen that by changing the gate diameter from 2 mm to 2.5 mm, the sprue portion, the runner portion, the second sprue portion, and the gate portion have optimal design dimensions with minimum temperature rise.

[0050]

Injection mold flow analysis evaluation system according to the present invention is, sprue diameter, runner diameter, by performing resin filling analysis gate size as the parameters to calculate the pressure, the distribution of temperature A filling analysis unit, an index calculation unit that calculates an index value of each part under initial conditions of the sprue diameter, the runner diameter, and the gate diameter based on an analysis result of the filling analysis unit; and an index calculation unit. Based on the results of the initial analysis, the change in the index value of the part by changing the diameter of each part is calculated, and the appropriate index value for which the amount of change is equal to or less than a predetermined amount is determined, and each part of the initial analysis result is calculated. And a display for graphically displaying the suitability index value of each part determined by the index determination unit, so that the dimensions of the resin flow path without burnout can be seen at a glance. then From Rukoto, can always be carried out quantitative evaluation in product design, the variation of the evaluation manual as in the prior art, variations in determination method is prevented. In addition, since the quantitative evaluation can be performed, the number of mold corrections can be reduced, and as a result, the development period of one product can be significantly reduced.

[Brief description of the 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 resin flow path dimension.

FIG. 3 is a diagram showing an example of a molded product shape model.

FIG. 4 is a table showing initial values of the diameter of each part.

FIG. 5 is a graph showing an initial analysis result.

FIG. 6 is a graph showing the effect of expanding the diameter of the sprue portion.

FIG. 7 is a graph showing the effect of enlarging the diameters of the runner portion and the second sprue portion.

FIG. 8 is a graph showing an effect of enlarging the diameter of a gate portion.

FIG. 9 is a graph showing a final determination result.

FIG. 10 is a table showing finally obtained values of diameters of respective parts.

[Explanation of symbols]

 11 Filling analysis unit 12 Index calculation unit 13 Index judgment unit 14 Display unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45 / 76,45 / 26 B22D 17/32 G06F 17/50 620-628

Claims (1)

(57) [Claims] 1. A system for evaluating the size of a resin flow path from an injection molding machine to a mold in order to prevent scorching, which is a defect in appearance, occurring during injection molding, wherein the resin flow path is formed by the injection molding machine. sprue in order from the side, a runner, when configured by the respective parts of the gate, sprue diameter, runner diameter, by performing resin filling analysis gate size as each of the parameters, filling analyzer for calculating pressure, the distribution of temperature And an index calculation unit that calculates an index value of each part under the initial conditions of the sprue diameter, the runner diameter, and the gate diameter based on the analysis result of the filling analysis unit, and an initial analysis by the index calculation unit. Based on the result, a change in the index value of the part by changing the sprue diameter is calculated, and an index value of the sprue part of the initial analysis result is obtained by obtaining an appropriate index value in which the change amount is equal to or less than a predetermined amount. And a sprue diameter index determining unit that replaces the index value, based on the analysis result in which the index value is replaced by the sprue diameter index determining unit, then calculates a change in the index value of the part by changing the runner diameter, and calculates the change A runner diameter index determining unit that determines an aptitude index value whose amount is equal to or less than a predetermined amount and replaces the index value with the index value of the runner unit of the analysis result, based on the analysis result in which the index value is replaced by the runner diameter index determining unit, Calculating a change in the index value of the part by changing the gate diameter, obtaining an appropriate index value in which the amount of change is equal to or less than a predetermined amount, and replacing the analysis result with the index value of the gate part of the analysis result. A flow analysis evaluation of an injection molding die, comprising: a display unit that graphically displays the suitability index value of each part obtained by each of the index determination units. Stem.