JP2003112349A - Method and apparatus for analyzing injection molding as well as injection molding analytical program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for analyzing in which a flow analysis in the step of manufacturing a molding having an insert by injection molding is accurately, easily and rapidly performed and to provide a computer program for realizing such an analyzing method. SOLUTION: The method for analyzing the injection molding comprises the steps of performing the flow analysis by dividing into a plurality of time steps and predicting the deformed state of the insert due to a flowing pressure. The method further comprises the steps of correcting the channel of the flowing matter from the displacing amount of the insert, and performing the flow analysis of the next step. This is performed until the flow is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding analysis method and apparatus for insert molded products.

[0002]

2. Description of the Related Art In the case of resin injection molding as an example, an insert molded product is a process in which a so-called insert such as a metal fitting is placed in a mold as shown in FIG. 8 and a resin is injection molded therein. It is a molded product obtained by (so-called overmolding) in which the insert and the resin are integrated.

Conventionally, as a method of analyzing the flow state of a fluid when manufacturing a molded article into which the insert has been inserted by injection molding, the insert has been regarded as an undeformed obstacle. That is, the insert was set as a part of the wall forming the flow path, and the flow analysis and the deformation analysis were performed only on the fluid overmolded around it.

[0004]

However, in such an insert molding flow analysis, the actual flow pattern may be inconsistent with the prediction by the flow analysis, or the deformation of the molded product may be predicted based on the result of the flow analysis. However, there was a problem that it did not match the actual state.

The present invention has been made in view of the above situation, and an analysis method capable of accurately, easily and quickly performing flow analysis in the process of manufacturing a molded article having an insert by injection molding. And an apparatus and a computer program for realizing such an analysis method.

[0006]

According to the present invention, when performing a flow analysis in the process of manufacturing a molded article having an insert by injection molding, the initial shape data of the insert and the initial shape data of the flow path of the fluid are obtained. An initial analysis shape data setting step for setting, a flow analysis step for executing a flow analysis of a fluid in the flow path, and an insert for analyzing a deformed state of the insert due to a flow pressure generated by the flow obtained by the flow analysis step It is an injection molding analysis method characterized by having an object deformation analysis step.

The present invention is also an injection molding analysis device for performing flow analysis in the process of manufacturing a molded article having an insert by injection molding, wherein the initial shape data of the insert and the initial shape of the flow path of the fluid. Initial analysis shape data setting means for setting data, flow analysis means for executing flow analysis of fluid in the flow path, and analysis of deformation state of insert due to flow pressure generated by flow obtained by the flow analysis means The injection molding analysis apparatus is characterized by having insert deformation analysis means for

Further, the present invention is a program for executing each step of the above-described flow analysis method by using a computer, and a computer-readable storage medium storing the program.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the flow analysis of insert molding, the inventors examined the cause of the actual flow pattern being inconsistent with the prediction by the flow analysis. As a result, as described above, the conventional flow analysis method in insert molding considers the insert as an obstacle that does not deform, but in reality, the insert is deformed by the flow pressure generated by the flow of the fluid, Along with that, it was found that the shape of the flow path was also greatly affected by the change from the initial shape.

In the present invention, in the initial analysis shape data setting step, the initial shape data of the insert is set, and the initial shape of the flow path of the fluid is obtained from the shape of the mold and the initial shape of the insert. Set the data. The shape data is created using shape input software such as I-DEAS (SDRC).

In the flow analysis step, first, the flow analysis of the fluid in the flow channel is executed based on the initial shape data of the flow channel.

Flow analysis is performed by giving flow shape data, flow characteristic data such as viscosity, and molding conditions such as temperature and inlet velocity to obtain TIMON (Toray), MOLDFLOW (Moldflow), Star-CD. It is executed by flow analysis software such as (C-Adapco). By flow analysis,
A flow state such as a flow velocity of the fluid in the flow channel or a flow pressure generated by the flow is required.

In the insert deformation analysis step, the influence of the flow pressure around the insert obtained on the flow analysis step on the insert is calculated and executed. Deformation analysis uses NASTRAN (MSC) and NASTRAN (MSC) as constraints with the installation method of the insert in the mold and the flow pressure as the load condition.
Conducted using structural analysis software such as ABAQUS (HKS). Here, the installation method of the insert in the mold refers to a condition of how to fix the insert when installing the insert in the mold.

As described above, by analyzing the deformation state of the insert, it becomes possible to calculate the change in the flow path due to the deformation of the insert during molding. Specifically, the analysis result in the flow analysis process is output in a plurality of time steps, the deformation of the insert is analyzed by the insert deformation analysis process at each hour step, and the flow path shape data correction process is performed. The shape data is corrected, and the flow analysis at the next time step is executed based on the corrected flow path shape data. As a result, it is possible to perform a flow analysis that is more suitable for an actual flow condition than a flow analysis method that performs a flow analysis by regarding a conventional insert as an undeformed obstacle.

In the conventional insert molding,
Due to the deformation of the insert, a portion originally supposed to be overmolded with resin may be exposed on the surface, and a molded product as designed may not be obtained. On the other hand, according to the flow analysis method of the present invention, by analyzing the deformation state of the insert, the shape of the insert after molding can be predicted before actual molding. Therefore, it is possible to simulate the shape of the insert after molding when the molding conditions, the initial shape of the insert, and the conditions such as a fixing place when the insert is installed in the mold are changed. This makes it possible to perform insert molding under appropriate conditions and obtain an insert molded product as designed.

Further, the molded product has a temperature higher than room temperature at the time of being projected out of the mold due to the heat received from the fluid at the time of molding, and deforms in the process of cooling to room temperature. In the deformation analysis process, this deformation is analyzed. The inventors investigated the cause of the difference between the analysis result and the actual deformation state of the molded product in the conventional deformation analysis process of the insert molded product. As a result, the following was found. That is, in the conventional deformation analysis of the insert-molded product at the time of molding, the insert was used as a rigid body and completely deformed. However, in reality, the insert and the fluid having different linear expansion coefficients are integrally deformed in the cooling process. Therefore, it was found that the deformed state was different from that when the insert was analyzed as a rigid body without deformation.

According to the injection molding analysis method of the present invention, when a molded product having an insert is injection molded and a deformation analysis for analyzing a deformed state after the molded product is ejected from a mold is performed, the insert and the flow are analyzed. Cooling analysis step to analyze the temperature change of the animal, deformation of the molded product that occurs when the molded product is cooled by using the temperature change obtained in the cooling analysis step, and the insert and the fluid are integrated It is preferable to have a deformation analysis step of analyzing as what is deformed. Here, a fluid such as a resin is referred to as a fluid after being solidified in order to distinguish it from an insert.

In the present invention, in the cooling analysis step, the temperature shift of the fluid during the flow is calculated in consideration of the physical properties such as the density of the mold and the insert, the specific heat, the thermal conductivity, the heat transfer coefficient and the initial temperature. To do. It is common to analyze the temperature shift by setting the initial temperature of the mold as the set temperature and the initial temperature of the insert as room temperature, but it is difficult to obtain an accurate value for the heat transfer coefficient, which is one of the thermophysical properties. Therefore, for simplicity, the surfaces of the mold and the insert may be subjected to cooling analysis with a constant temperature, and the surface temperature of the fluid when ejected may be calculated as the temperature of the insert when ejected.

In the deformation analysis step, the temperature of the fluid at the time of ejection and the temperature of the insert obtained in the cooling analysis step are used as thermal loads, and the elastic modulus, Poisson's ratio and linear expansion coefficient of the fluid and the insert are taken into consideration. As a result, a deformation analysis is performed assuming that both are deformed as a unit and the deformation state of the molded product is predicted.

If the fluid is a resin, it may contain a substance such as glass fiber that causes anisotropy in the mechanical properties of the fluid. In this case, the fiber orientation analysis is performed to determine the anisotropy. By considering the mechanical properties of the fluid, a more accurate deformation analysis of the insert molded product can be executed.

As a result, the deformation analysis of the insert-molded product, which could not be predicted accurately in the past, can be executed in a more practically suitable form.

If the anisotropic property of the fluid and the mechanical property of the insert used in the deformation analysis during molding are used and it is assumed that the fluid and the insert part are integrally deformed, a load other than temperature is applied. It is also possible to predict the strength of the insert-molded product in consideration of the anisotropy when added.

An embodiment of flow analysis of an insert molded article will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of an apparatus for analyzing a flow state in consideration of an insert of the present invention. In this embodiment, (100) is a computer, (101) is a keyboard, (102) is a mouse,
(103) is a display and (104) is an auxiliary storage device. In (104), in addition to the hard disk device, M
Removable auxiliary storage devices such as O, PD, and DVD are also available.

The auxiliary storage device includes an insert and an initial shape data storage means (105) for the flow path of the fluid to be overmolded on the insert.

The computer (100) has an initial shape data setting means (106) for a flow path of an insert and a fluid flown overmolded on the insert, a flow analysis means (107), and a deformation analysis means (108) for the insert. ),
A means (109) for correcting the flow path shape of the fluid by the deformation of the insert is included.

FIG. 2 shows a flowchart of an embodiment of the present invention. The flow analysis means (107) of step 202 is
First, in step 201, the initial shape data for analysis created by the shape data setting means (106) for the flow path of the insert and the fluid is read, the flow characteristics and molding conditions of the fluid are input, and a plurality of output times are set. Perform a flow analysis of the first time step, divided into steps. The flow path shapes of inserts and fluids used for analysis are defined by CAE analysis shape data, which are generally called meshes and consist of nodes and elements, element properties, and material properties. This mesh has one-dimensional beam element, two-dimensional shell element, three-dimensional solid element type,
Most of the flow passage shapes of the fluid used in the present invention are shell elements or solid elements.

Generally, viscosity, density, specific heat and thermal conductivity are considered as the flow characteristics of the fluid. Further, as the molding conditions, the initial temperature of the fluid, the inflow speed, the mold temperature, etc. are input.

In step 204, the flow pressure generated by the flow during one time step is added to the mesh of the insert portion where the flow is completed during the time step as a load condition, and the insert in the mold is performed. The deformation state of the insert is analyzed under the constraint of the installation method of the insert. Step
205 corrects the flow path of the fluid from the displacement amount of the insert subjected to the deformation analysis, that is, corrects the flow path shape data,
In step 202, the flow analysis of the next time step is performed on the corrected flow path shape. Steps 202 to 205 are repeated until the flow is completed.

Next, the method of correcting the flow path shape of the fluid in step 205 will be described in detail. When the flow path is defined by a shell element, the element property has wall thickness information. A flow path that reflects the deformation of the insert by adding or subtracting the displacement amount of the insert calculated from the deformation analysis of the insert to the wall thickness data of the shell element that defines the flow path at the same position. The shape is obtained. By making the direction of the shell element defining the flow path in the direction in which the shell element is in contact with the insert, it is possible to easily determine the increase or decrease of the flow path thickness due to the deformation of the insert.

When the flow path is defined by a solid element, the displacement amount of the insert calculated from the deformation analysis of the insert is added to the node position forming the solid element defining the flow path at the same position. Then, the flow path shape is corrected. When the amount of displacement of the insert is large and the correction of the node position on the solid element that is considered to be in the same position becomes large, which affects the quality (aspect ratio, twist, collapse) of the solid element shape to which it belongs. Because there is
The surrounding nodes may be moved so as to maintain the quality of the solid element by matching the displacement amount of the insert with the movement amount of the node on the solid element at the same position. As a method of moving the surrounding nodes, there are the Laplacian method and the centroid method, which are also installed in FEMAP (made by SDRC).

FIG. 3 and subsequent figures show specific flow analysis examples of insert-molded products in resin injection molding.

FIG. 3 shows the shape data of an insert having a thickness of 100 mm × 100 mm and a thickness of 1 mm, which is formed by solid elements.

FIG. 4 shows the shape data of the resin flow path portion overmolded on the upper and lower surfaces of the insert of FIG.
The insert is exposed at four places of 20 mm × 30 mm in the mm × 100 mm portion. It is made of a shell element whose one side has a size of 10 mm, and has a channel wall thickness of 2.5 mm on the upper surface and a channel wall thickness of 2.0 mm on the lower surface as viewed in FIG.

FIG. 5 shows a filling time of 1 se for the flow path of FIG.
In c, the flow pattern was analyzed without considering the insert and the result of the pressure at the time of completion of filling is shown in FIG. 6. In FIG. 6, the flow pattern and filling considering the deformation of the insert under the same conditions as the filling time of 1 sec and the filling The pressure results at completion are shown. In the filling pattern, the state of progress of the flow front in the process of injection molding is displayed in contour lines every 0.2 sec, and the flow pressure result shows the pressure distribution of the fluid at the completion of filling of 2 MPa.
Each contour line is displayed.

FIG. 7 shows the deformation mode of the insert due to the flow pressure when the filling rate is 50%.

As shown in FIGS. 5 to 7, in the analysis considering the insert, the resin pressure received from the upper surface where the flow is fast deforms the insert in the lower surface direction, so that the flow thickness of the lower surface portion is reduced. It has been analyzed that the lower surface has slower flow and the upper surface has faster flow.

The above embodiment is realized by a computer and a program including a flow analysis. Such programs include flexible disk, MO, CD-RO.
It is distributed through a transmission medium such as a computer-readable tangible medium such as M or a wired or wireless network.

[0039]

EFFECTS OF THE INVENTION According to the present invention, it is possible to easily and speedily predict the flow pattern and the deformation state of a molded product when the restraint conditions and shape of the insert are changed, and the insert is included. It is possible to improve the efficiency of product design of molded products.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a flow chart diagram of an example embodiment of the present invention.

FIG. 3 is shape data of inserts of 100 × 100 × 1 mm.

4 is flow path shape data of a fluid to be overmolded on the insert of FIG.

5 is a flow analysis result (flow pattern, pressure distribution) for the flow path of FIG.

6 is a flow analysis result (flow pattern, pressure distribution) considering deformation of the insert of FIG. 3 due to flow pressure with respect to the flow path of FIG. 4.

7 is a deformation analysis result (deformation mode diagram) of the insert of FIG. 3 due to a flow pressure when the filling rate of the flow path of FIG. 4 is 50%.

FIG. 8 is an insert-molded product molded by resin injection molding.

[Explanation of symbols]

100 computers 101 keyboard 102 mice 103 display 104 auxiliary storage 105 Insert, flow path shape data storage means 106 Insert, flow path shape data setting means 107 Flow analysis means 108 Deformation analysis means of insert due to resin pressure 109 flow path shape correction means

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Claims (9)

[Claims] 1. An initial analysis shape data setting step of setting initial shape data of an insert and initial shape data of a flow path of a fluid when performing a flow analysis in a process of manufacturing a molded article having an insert by injection molding. And a flow analysis step of performing a flow analysis of the flow material in the flow path, and an insert deformation analysis step of analyzing the deformation state of the insert due to the flow pressure generated by the flow obtained by the flow analysis step. Characteristic injection molding analysis method. 2. The injection molding analysis method according to claim 1, further comprising a flow path shape data correction step of correcting flow path shape data based on the deformation of the insert material obtained in the insert deformation analysis step. 3. An analysis result in a flow analysis step is divided into a plurality of time steps and output, and the insert deformation is analyzed by an insert deformation analysis step at every hour step, and a flow path shape data correction step is performed. 3. The injection-molding analysis method according to claim 2, wherein the step of correcting the shape data of 1. and repeating the flow analysis of the next time step based on the corrected flow path shape data. 4. A cooling analysis step of analyzing a temperature change of an insert and a fluid, a deformation of a molded article caused when the molded article is cooled, using the temperature change obtained in the cooling analysis step, and The injection molding analysis method according to claim 1, further comprising a deformation analysis step of analyzing that the insert and the fluid are integrally deformed. 5. An injection molding analyzer for performing flow analysis in the process of manufacturing a molded article having an insert by injection molding, wherein initial shape data of an insert and flow path initial shape data are set. Initial analysis shape data setting means, flow analysis means for performing flow analysis of the fluid in the flow path, and insert deformation for analyzing the deformation state of the insert due to the flow pressure generated by the flow obtained by the flow analysis means An injection molding analysis device comprising an analysis means. 6. The injection molding analysis apparatus according to claim 5, further comprising flow path shape data correction means for correcting the flow path shape data based on the deformation of the insert. 7. A cooling analysis means for analyzing a temperature change of an insert and a fluid, and a deformation of the molded product caused when the molded product is cooled, using the temperature change obtained in the cooling analysis step, and The flow analysis apparatus according to claim 5, further comprising deformation analysis means for analyzing that the insert and the fluid are integrally deformed. 8. An injection molding analysis program for executing each step of the injection molding analysis method according to claim 1 by using a computer. 9. A computer-readable storage medium storing the program according to claim 8.