JP2008200859A - Warpage analysis method, its program, and warpage analysis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for simply and precisely predicting the shrinkage rate and warpage quantity of a molding in the injection molding process. <P>SOLUTION: In order to analyze the warpage of the molding, the total warpage quantity is calculated on the basis of (1) a branching structure warpage quantity obtained from the angle between a base part and a branching body in a branching part, the wall-thicknessward average of an inward shrinkage rate in a branching part, etc., and (2) a bimetal warpage quantity obtained from the inward and wall-thicknessward distribution of the inward shrinkage rates of the base part and the branching part in the branching part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a warp deformation analysis method, a program thereof, and a warp deformation analysis apparatus.

  The background art will be described below with reference to the accompanying drawings.

  1A to 1E are diagrams schematically illustrating a typical example of an injection molding process for performing injection molding of a molded product made of resin, metal, or the like. In the injection molding, the molding material 6 is heated and melted into a fluid state by an injection molding machine as shown in FIG. 1A, and pressurized and injected into the cavity 5 (mold cavity) of the mold 4. In this technique, the shape corresponding to the cavity 5 is formed by solidifying with, and the mold is opened, and the solidified molded product 7 is taken out from the inside of the mold. Usually, the injection molding process can be roughly divided into four processes shown in FIGS. 1B to 1E. Hereinafter, an explanation will be given by taking injection molding of a resin product as an example.

  FIG. 1B is a diagram illustrating an example of a resin filling step in a resin product injection molding step. In the filling process of FIG. 1B, the granular molding material 6 put into the hopper 2 by the motor 1 is melted in the cylinder 3 and filled into the cavity 5 of the mold 4 with the screw in the cylinder 3. . FIG. 1C is a diagram illustrating an example of a resin pressure holding step in the resin product injection molding step. In the pressure-holding process of FIG. 1C, pressure is applied to the melted molded article material 6 to compensate and stabilize the shrinkage of the material at the initial stage of the cooling process. FIG. 1D is a diagram illustrating an example of a resin cooling step in the resin product injection molding step. In the cooling process of FIG. 1D, the molded product material 6 is cooled and solidified by the mold 4 to shape the shape of the cavity 5 into the molded product. The pressure holding process in FIG. 1C and the cooling process in FIG. 1D may be collectively referred to as a cooling process or a pressure holding cooling process. FIG. 1E is a diagram illustrating an example of a mold release process (mold opening) in the resin product injection molding process. 1E, the mold 4 is opened, and the solidified molded product 7 is taken out from the mold 4. Injection molding is typically a technique for obtaining a product by shaping the shape of the cavity 5 of the mold 4 into a molded product through these four steps.

  However, in any of the filling process, pressure holding process, and cooling process, the behavior inside the mold is a black box. Conventionally, when performing injection molding, the prototype mold is modified based on experience and intuition. The mold was designed while the molding conditions were set by trial and error. As a result, the number of mold prototyping increases, and the product development period becomes longer, which tends to increase the development cost.

  On the other hand, instead of relying on experience and intuition, the flow of melting in the mold in the filling process in advance, the orientation of the molding material, molding material and reinforcing fiber, the temperature and pressure in the holding pressure cooling process, etc. Analyzes the physical history of the machine numerically by computer, predicts shrinkage and deformation after taking out the molded product from the mold, and feeds back the result to mold design and molding condition setting, shortening the development period A method has been proposed.

  FIG. 2 is a flowchart showing an example of the configuration of the conventional injection molding process numerical analysis technique disclosed in Patent Document 1 and Patent Document 2. Conventionally, as shown in the flow chart of FIG. 2, the injection molding analysis shape data is input (step 200), the gate that is the injection point of the molded product material is designated, and the density, specific heat, and heat conduction of the molded product material are specified. Rate, heat transfer coefficient between the molding material and the mold, melt viscosity characteristics of the molding material, PVT characteristics (pressure-volume-temperature characteristics, ie, the specific volume or volume of the molding material is the relationship between temperature and pressure. The physical property data such as those expressed by the formula) and molding conditions such as molding temperature, mold temperature, injection rate (or injection time), holding time, holding pressure, etc. are input (step 201, step 202). Then, analysis of the injection molding process (step 203) (filling process analysis (step 204), pressure holding / cooling process analysis (step 205), orientation analysis (step 208)) is performed, and each of the shape data for injection molding analysis is analyzed. Element The shrinkage rate at each node is calculated (step 206), and structural analysis is performed to analyze warpage deformation of the molded product (warp deformation due to the bimetal effect) (step 207) and output (step 209). .

  For example, when a flat plate is molded, if there is a difference in the mold temperature between the front and back of the flat plate, the surface with the high mold temperature will shrink more than the surface with the low mold temperature when cooled to room temperature, and the bimetal will Due to the effect, it becomes warped deformation like a concave surface with a high mold temperature, but in the injection molding analysis, not only the shrinkage distortion caused by the temperature difference between the front and back of the mold, but also the density and specific heat of the molded product material, The distribution of shrinkage strain due to thermal conductivity, heat transfer coefficient, melt viscosity, and PVT characteristics is calculated at all parts of the molded product, and the warpage deformation of the molded product as a whole is calculated. .

  There are many injection molding analysis software that performs warp deformation analysis, but it is pointed out that analysis accuracy is lower than that of linear structural analysis such as beam deflection calculation, and absolute value evaluation and relative value evaluation may not be possible. ing. This is because in warp deformation analysis, there are various error factors such as temperature, pressure, resin data, resin flow history, conditions after removal from the mold, analysis model, etc., which are not in linear structure analysis. is there.

  For example, Non-Patent Document 1 states that it is difficult to obtain an absolute value for the warpage deformation amount analysis result of injection molding, and it is difficult to obtain an accuracy exceeding the range of comparative study.

  In particular, it is particularly difficult to analyze the amount of warpage deformation of a molded product having a flat plate shape on which branch bodies such as ribs are formed.

  For example, in Non-Patent Document 2, a simple rib-shaped molded product is compared between an actual measurement value and an analysis value, but the warpage deformation amount is different from 2 to 11 times between the actual measurement value and the analysis value. Evaluation of values has become difficult.

  Furthermore, in Non-Patent Document 3, since the result of warping is not a normal analysis condition, it is stated that the actual measurement value and the analysis value are combined by adjusting the parameter for adjusting the thermal conductivity coefficient of the L-shaped corner portion. It can be seen that the experience and know-how of the analyst are necessary to match the measured value and the analyzed value of the sled.

  In order to share the experience and know-how of this analyst, in Non-Patent Document 4, material manufacturers, mold manufacturers, software vendors, etc. participate and compare measured values and analyzed values for ribbed plates. ing. In this, it is shown that there is a difference in analysis results not only between analysis softwares but also between analysts. In other words, it suggests that different results occur depending on the experience and know-how of the person in charge of analysis, and the present situation is that a universal warpage deformation analysis method has not yet been established.

  For this reason, the injection molding phenomenon cannot be predicted by numerical calculation in advance, and the design of the mold proceeds in the wrong direction due to the analysis by numerical calculation. However, the development cost may be high. Therefore, increasing the accuracy of warping analysis is a very big issue.

  By the way, the analysis of the injection molded product is performed using a shell element or a solid element. FIG. 3A is a diagram illustrating an example of a method of replacing a certain shape of a three-dimensional volume with a two-dimensional plane (shell element). As shown in FIG. 3A, a two-dimensional shell element means that a shape having a three-dimensional volume is replaced with a two-dimensional plane (shell element), and thickness data is given to the two-dimensional plane shape. It represents a dimensional shape. In general, an injection-molded molded article is configured to have a thin shape, and thus is often analyzed using a shell element. This is because when shell elements are used, there is no need to create analysis elements in the thickness direction, so there is an advantage that the calculation cost can be reduced, and there is an advantage that it is easy to study the shape such as changing the wall thickness. Because there is.

  FIG. 3B is an example in which a filling analysis of injection molding is performed using the solid element 301 and the shell element 304, respectively. For the filling analysis, the result is almost the same whether the solid element is used or the shell element is used.

  Next, the warpage deformation amount deformation analysis of a molded product will be described by taking an L-shaped shape as an example. FIG. 4A is an example of an L-shaped shape, and FIGS. 4B to 4F schematically show the behavior of contraction deformation and warpage deformation of a shell element with a three-dimensional volume. In FIG. 4A, it is assumed that the mold surface 402 of the inner part of the L-shaped shape 401 is hotter than the mold surface of the outer part, cooled to room temperature, and contracted. In this case, due to the bimetal effect, a warp deformation 403 that falls inward at an L-shaped corner portion occurs. When this is modeled by the shell element of FIG. 4B, deformation calculation is performed so that the inner surface of the L-shaped corner is more contracted than the outer surface of each element of FIG. 4B. As a result, the warp deformation that falls inward at the corner portion of the L-shaped shape can be reproduced in the computer by the bimetal effect, similar to the contraction deformation in the solid element. As a result, warpage deformation due to the bimetal effect generated by the temperature distribution in the in-plane direction and the thickness direction (in-plane direction, shrinkage rate distribution in the thickness direction) is analyzed with the shell element at the corner portion of the L-shape. Even if a solid element having a three-dimensional volume is analyzed, a reasonable result can be obtained to some extent.

  However, unlike the flat plate portion, the L-shaped corner portion has an in-plane shrinkage rate (in this case, an in-plane direction that is bent at the corner portion and an intersection forming the corner portion). The warp deformation also occurs due to the difference between the shrinkage rate in the direction perpendicular to the direction of the line (the shrinkage rate in the in-plane bending direction at the corner portion of the L-shaped shape) and the shrinkage rate in the thickness direction. It is enough.

  This mechanism will be described with reference to an L-shaped molded product in FIG. 4C.

  It is assumed that the shrinkage 407 in the thickness direction is larger than the shrinkage 408 in the in-plane direction (in-plane bending direction component at the corner portion) due to the orientation of the molded article material and the influence of the filler. 4D is an in-plane cross-sectional view including the bending direction of the molded product surface of FIG. 4C. As shown in FIG. 4D, the angle formed by the two surfaces constituting the L-shaped shape of the L-shaped corner portion. When the half shape is considered with the surface 409 that equally divides the angle as the boundary, since the shrinkage in the thickness direction is large, the angle 410 becomes small, and when the shape after the shrinkage is combined on the surface 409 that equally divides the angle, L Sled deformation that falls inward at the corners of the letter shape occurs. This is warpage deformation in which warpage deformation occurs due to the difference between the in-plane direction shrinkage rate (component perpendicular to the L-shaped corner portion) and the thickness direction shrinkage rate.

  When the solid element is used, such a corner behavior can be reproduced. When this is modeled by the shell element of FIG. 4E, the shell element has an L-shaped shape such as an angle 410 of FIG. 4D. Since the angle of the corner portion is not taken into consideration, even if the angle 410 changes, the shell element does not undergo warping deformation that falls inward at the L-shaped corner portion.

  However, even when a solid element is used, the warp deformation of the L-shaped corner part is correctly analyzed when the contraction 407 in the thickness direction is larger than the contraction 408 in the in-plane direction (in-plane bending direction component of the corner part). It is not always possible. FIG. 4F is a model of the L-shaped molded product of FIG. 4C with a different number of divisions. As shown in FIG. 4F, in the case of a solid element 411 having an insufficient number of element divisions in an L-shaped corner part, the analysis is correctly performed as if the solid element 412 has an adequate number of element divisions in an L-shaped corner part. Can not do it. This is because a solid element with an insufficient number of element divisions, like a shell element, cannot divide an L-shaped corner portion by a surface 409, and represents an angle change of the L-shaped corner portion. It is because it cannot be done. Therefore, when using solid elements, it is necessary to create a model including a large number of elements, which is disadvantageous in terms of calculation cost and model creation man-hours.

  In addition, as described above, the two-dimensional shell model considering only the bimetal effect cannot analyze warp deformation caused by the difference between the in-plane direction shrinkage rate and the thickness direction shrinkage rate.

  Therefore, in Non-Patent Document 5, with respect to the L-shaped corner portion, the L-shaped corner portion is determined from the shrinkage in the in-plane direction and the shrinkage in the thickness direction as in Equations (1) to (3). The angle between the two sandwiched surfaces causes an angle change before and after the contraction, thereby expressing the contraction and warping deformation behavior of the L-shaped corner portion.

  FIG. 5A is an example of a diagram illustrating a method of calculating the angles of Expression (1) and Expression (2), and is a cross-sectional view illustrating the shape before and after contraction of an L-shaped corner curved surface. FIG. 5B is an example of a diagram illustrating a method of calculating the angle of Expression (3), and two surfaces constituting an L-shaped shape indicating a shape before and after contraction of a corner portion of an L-shaped corner. 5 is a cross-sectional view of a half shape with a plane that equally divides the angle formed by

  Hereinafter, FIGS. 5A and 5B will be described in detail.

  Here, an L-shaped corner shape having a curved corner surface is assumed instead of a branched portion.

  Assuming that the shape 501 before shrinkage is an inner diameter R and a wall thickness d, shrinkage is caused by shrinkage of Sx in the in-plane direction (circumferential direction) and Sz in the wall thickness direction (radial direction) due to heat shrinkage after molding. A change in shape when the shape 502 is changed to the later shape is shown. At this time, if the in-plane direction shrinkage rate Sx and the thickness direction shrinkage rate Sz are equal, and if the shrinkage rate is the same on the inside and outside of the corner curved surface, the angle change after shrinkage does not occur, and the shrinkage The later angle change amount Δα = 0. However, when the thickness direction shrinkage rate Sz is larger than the in-plane direction shrinkage rate Sx, distortion occurs between the in-plane direction (circumferential direction) and the thickness direction (radial direction), and the equation (1), A change in the angle of the corner as shown in Equation (2) occurs.

FIG. 5B illustrates an L-shaped corner portion that is divided by a plane that equally divides an angle formed by two surfaces constituting the L-shaped shape. When the tip of the L-shaped corner portion is not a curved shape, the corner portion can be expressed by the model shown in FIG. 5B. The angle α before contraction and the angle β after contraction are expressed by the equation (3) from FIG. 5B. Can be converted to
It should be noted that equations (1) to (3) can be considered to be substantially the same when the amount of change in angle before and after contraction is considered to be minute.

  The warpage deformation analysis of the L-shaped corner portion considering the difference between the in-plane direction shrinkage rate and the wall thickness direction shrinkage rate shows that when a filler such as fiber is contained in the molded product, Since warpage appears particularly prominently, the method of Non-Patent Document 5 is very effective.

However, according to the knowledge of the present inventors, in the case of a molded product such as a rib shape in which a branched body such as a rib is formed on the base portion, the same formula (1) as the L-shaped corner portion is obtained for the branched portion. ) To Equation (3), there is a problem that it is not possible to consider that the warpage deformation at the branching portion changes depending on the flow rate of the material containing the filler such as fiber to each branching body. . In addition, since it has not been scrutinized as a shape that induces warping as a shape, for example, even if the shape is a small protrusion with respect to the base portion as shown in FIG. There was a problem that would be calculated if.
JP 62-34282 A JP-A-2-258229 Yonekawa, “CAE analysis of plastic products (current situation and issues)”, molding, Japan, 2000, VOL. 12, no. 3, P133 Hiromi Otsuka / Tomohito Mochizuki / Harunobu Osuka, “Prediction accuracy of rib deformation by warp deformation analysis”, Molding, Japan, 2001, VOL. 13, no. 2, P102 Kazuyoshi Yamada / Eihito Saigo / Hirotaka Tanaka, “Prediction of warpage deformation in corners of injection molded products”, Molding, Japan, 2002, VOL. 14, no. 8, P496 Masaru Yamabe / Hiroki Otsuka / Takao Kameda / Masahiro Seto / Takayuki Doi, “Activity Report of Injection Molding CAE Technical Committee -Comparison between Analysis and Molding Experiment by Each Member”, Molding, Japan, 2002 , VOL. 14, no. 11, P690 A. AMMAL / V. LEO / G. REGNIER, “Corner Deformation of Injected Thermoplastic Part”, International Journal of Forming Processes, France, 2003, ARTICLE VOL 6/1-, P53

  As described above, simply applying the approach of Non-Patent Document 5 to a shape having a branch such as a rib shape, the amount of change in the angle of the branch portion due to the difference between the in-plane direction shrinkage rate and the thickness direction shrinkage rate is calculated. In this case, the influence of the flow at the branching part and the influence of the shape of the branching body were not taken into consideration, so that the actually measured warpage deformation amount and the analysis warpage deformation amount were sometimes different.

  Therefore, as a result of the diligent study by the present inventors, in addition to the shrinkage calculation based on the temperature distribution, the shrinkage calculation based on the temperature and pressure distribution, the anisotropic shrinkage calculation based on the orientation distribution, and the calculation of the change in the angle of the corner portion. Regarding the warpage deformation of the branch part, it was found that the warpage deformation amount of the analysis value can be made very close to the actually measured warpage deformation amount by taking into consideration the shape of the branch part and the flow history.

  An object of the present invention is to provide an injection molding analysis method capable of accurately performing a warp deformation analysis on a branch portion of a shape having a branched body such as a rib shape, in consideration of the problems of the above prior art, and a warp deformation amount analysis related to injection molding. The purpose is to provide the program.

In order to achieve the above object, according to the present invention, there is provided a warpage deformation analysis method for analyzing warpage deformation of a molded product by a programmed computer, wherein warpage deformation at a branch portion of the molded product is performed.
(1) The angle formed by the base portion and the branch body at the branch site, the average value in the thickness direction of the in-plane shrinkage rate at the branch site, and the thickness direction average of the thickness direction contraction rate at the branch site A branch structure warpage deformation amount calculating step for calculating a branch structure warpage deformation amount calculated based on the value and the branch structure parameter;
(2) In-plane direction and thickness direction distribution of in-plane direction shrinkage rates of the base portion and the branch body in the branch portion, and in-plane thickness direction shrinkage rates of the base portion and the branch body in the branch portion A bimetal warp deformation amount calculating step for calculating a bimetal warp deformation amount calculated based on the direction and thickness direction distribution;
(3) a branch part total warpage deformation amount calculating step of calculating a total warpage deformation amount based on the calculation results of the branch structure warpage deformation amount calculation step and the bimetal warpage deformation amount calculation step;
There is provided a warp deformation analysis method characterized by comprising:

  According to a preferred embodiment of the present invention, as the branch structure parameter, the distance from the branch site to the tip of the branch body, the flow history at the branch site, the thickness of the base portion at the branch site and the branch site At least one or more of the ratio between the thickness of the branch body and the thickness of the base portion at the branch site and the distance from the branch site to the tip of the branch body is used. A warp deformation analysis method is provided.

  Further, according to a preferred embodiment of the present invention, as the branching structure parameter, a warpage deformation characterized by using a ratio between the thickness of the base portion at the branching portion and the thickness of the branching body at the branching portion. An analysis method is provided.

  According to a preferred aspect of the present invention, there is provided a warp deformation analysis method characterized by using the following equation or a mathematically equivalent equation for calculating the branch structure warp deformation amount.

  According to a preferred aspect of the present invention, there is provided a warp deformation analysis method characterized by using the following equation or a mathematically equivalent equation for calculating the branch structure warp deformation amount.

  Further, according to a preferred embodiment of the present invention, as the branching structure parameter, a ratio between a thickness of the base portion at the branching portion and a thickness of the branching body at the branching portion, and the base at the branching portion. A warp deformation analysis method is provided, which uses a ratio between a thickness of a portion and a distance from the branching portion to the tip of the branching body.

  According to a preferred aspect of the present invention, there is provided a warp deformation analysis method characterized by using the following equation or a mathematically equivalent equation for calculating the branch structure warp deformation amount.

  According to a preferred aspect of the present invention, there is provided a warp deformation analysis method characterized by using the following equation or a mathematically equivalent equation for calculating the branch structure warp deformation amount.

  Further, according to a preferred embodiment of the present invention, as the branching structure parameter, a ratio between a thickness of the base portion at the branching part and a thickness of the branching body at the branching part, and a flow history at the branching part There is provided a warp deformation analysis method characterized by using

According to a preferred aspect of the present invention, there is provided a warp deformation analysis method characterized by using the following equation or a mathematically equivalent equation for calculating the branch structure warp deformation amount.

  According to a preferred aspect of the present invention, there is provided a warp deformation analysis method characterized by using the following equation or a mathematically equivalent equation for calculating the branch structure warp deformation amount.

  According to a preferred embodiment of the present invention, there is provided a warp deformation analysis method characterized in that the molded product is an injection molded product of a resin material.

  According to a preferred embodiment of the present invention, there is provided a warp deformation analysis method characterized in that the molded product is an injection molded product of a resin material containing a filler.

  According to another aspect of the present invention, there is provided a program for causing a computer to execute each step of any of the above warp deformation analysis methods.

  Moreover, according to another form of this invention, the computer-readable recording medium which recorded the said program is provided.

Moreover, according to another aspect of the present invention, an injection molding analysis apparatus for analyzing an injection molding process of a molded product,
Warpage deformation at the branch part of the molded product,
(1) The angle formed by the base portion and the branch body at the branch site, the average value in the thickness direction of the inward front direction shrinkage rate at the branch site, the thickness direction shrinkage rate at the branch site, and the branch structure parameter And (2) warpage deformation at the branch portion of the molded product, and the in-plane direction of the in-plane shrinkage of the base portion and the branch body at the branch portion, and (2) Bi-metal warp deformation amount calculating means for calculating based on the thickness direction distribution and the in-plane direction and the thickness direction distribution of the shrinkage rate in the thickness direction of the base portion and the branched body at the branch portion;
(3) a branch portion total warpage deformation amount calculation means for calculating warpage deformation at the branch portion of the molded product based on an output of the branch structure warpage deformation amount calculation means and an output of the bimetal warpage deformation amount calculation means;
There is provided an injection molding analyzer characterized by comprising:

  The terms are defined below.

  In the present invention, the “molded product” is a product molded by a molding process such as extrusion molding, blow molding, injection molding, injection compression molding, compression molding, transfer molding or the like. In the following description, injection molding will be described as a typical example in this specification. For example, the molded article is heated in a fluidized state by an injection molding machine as shown in FIG. 1A, and is injected into a cavity (cavity) of a closed mold and solidified in the mold. A product that is shaped to correspond to a mold cavity.

  In the present invention, “molded product material” refers to a polymer material or a metal material used for molding in injection molding or the like, and includes polyethylene (PE), polypropylene (PP), vinyl chloride (PVC), polyamide (PA), polyacetal. (POM), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), liquid crystal polymer (LCP), polyether nitrile ( PEN), polycarbonate (PC), modified polyphenylene ether (m-PPE), polysulfone (PSF), polyethersulfone (PES), polyarylate (PAR), polyamideimide (PAI), polyetherimide (PEI), Thermoplastic polyimide (PI), acrylonitrile butadiene styrene (ABS), and the like acrylonitrile styrene (AS), magnesium alloy (Mg alloy).

  In the present invention, the “L-shaped corner portion” refers to a portion where the surface is bent at an angle of less than 180 °.

  In the present invention, the “branch site” refers to a site where the cross-sectional shape in an arbitrary plane including the thickness direction of the base portion of the molded product branches into two or more. FIG. 6A to FIG. 6E show a typical example of the shape of a molded article having a branch portion by a shell model. As shown in FIG. 6A to FIG. 6E, the cross-sectional shape in the thickness direction of the molded product is T-shaped, Y-shaped, umbrella-shaped (2 branches), X-shaped (3 branches), star-shaped (maybe machine), etc. There is. Further, in the analysis, the “branch part” means that in the case of a shell element, an element 617 including a side 618 constituting the branch part as shown in FIG. 6F, and in the case of a solid element, a branch part as shown in FIG. 6G. The element 617 includes the node 619 of the element.

  In the present invention, the “base” refers to a part that forms the main shape of a molded product. For example, in the case of a T-shape, it refers to the remaining portion from which a protrusion such as a rib of a molded product is removed.

Which part of the molded product corresponds to the “base part” can be determined as follows. However, the determination of the base part based on this method does not have to be performed every time in the computer, and the procedure does not need to be the same. As a result, if there is a case where a part having the following definition is determined as the base part, the object of the present invention is achieved at least in that case.
(1) Recognize the number of branches at the branch site. In the case of two branches, the number of surfaces constituting the branch part is three, and if the number of branches is three, the number of surfaces is four.
(2) All the angles formed by the surfaces constituting the branching portions are calculated. For example, in the case of the T-shaped shape shown in FIG. 6A, an angle formed by the 606 surface and the 607 surface, an angle formed by the 606 surface and the 608 surface, and an angle formed by the 607 surface and the 608 surface (0 to 180 °). When it is assumed that the branch site is n-branch, there are n × (n + 1) / 2 angles formed by the surfaces.
(3) Of the angles (0 to 180 °) formed by the surfaces constituting the branching portion and the surfaces, the two surfaces having the largest angles are called base surfaces.

  For example, for the umbrella shape shown in FIG. 6C, there are three angles formed by the surfaces (the angle formed by the 609 surface and the 610 surface, the angle formed by the 610 surface and the 611 surface, and the angle formed by the 609 surface and the 611 surface). Of these, since the angle formed by the 609 plane and the 611 plane is the largest, the base planes are the 609 plane and the 611 plane.

  However, in the case of an X-shaped shape as shown in FIG. 6D or a star shape as shown in FIG. 6E, there may be a plurality of the largest angles (180 °). In that case, a surface having a large thickness is used as a base surface. For example, in FIG. 6D, if the 612 surface is 4 mm, the 613 surface is 3 mm, the 614 surface is 2 mm, and the 615 surface is 1 mm, the thickness of the 612 surface is the largest, so the 612 surface is paired with this. A surface 614 having a maximum angle of 180 ° with respect to the surface 612 is a base surface.

    In addition, when the base surface cannot be determined with the surface having the largest thickness (for example, when the surface of 612 is 4 mm, the surface of 613 is 4 mm, the surface of 614 is 3 mm, and the surface of 615 is 2 mm), it can be the base surface. Compare the surfaces (614 and 615) that are paired with the surface that is judged to have the largest wall thickness, and the two surfaces (612 and 614) including the larger one (614 and 614) And If the base surface cannot be determined, for example, when the thickness of the four surfaces is the same in the X-shaped shape as shown in FIG. 6D, any surface that can be the base surface can be regarded as the base surface. Absent. The part to which the base surface belongs becomes a “base part”. When using a solid element, it is essentially the same as described above.

  In the present invention, the “branch body” refers to a portion branched from a base portion in a branched portion of a molded product.

  In the present invention, the “angle formed between the base portion and the branch body” refers to an angle formed between the base portion and each branch body.

  For example, in the case of the T-shaped shape of FIG. 6A, the base portions are 606 and 608 surfaces, and the branch body is 607 surfaces, and the “angle between the base portion and the branch body” is 2 on the left and right sides of the branch body 607 surface. Exist (angle formed by 606 and 607 surfaces, angle formed by 607 and 608 surfaces). In the case of a T-shaped shape, the angle between the two surfaces constituting the base portion is 180 °, and therefore the two surfaces constituting the base portion are caused by the bimetal effect as shown in Patent Document 1 and Patent Document 2. Causes deformation only.

  Similarly, in the case of the umbrella-shaped shape in FIG. 6C, the base portion has 609 and 611 surfaces, and the branch body has 610 surfaces, and the “angle formed by the base portion and the branch body” is 2 on the left and right sides of the branch body 610 surface. Exist (the angle between the 609 plane and the 610 plane, the angle between the 610 plane and the 611 plane). However, when the two surfaces (609 surface and 611 surface) constituting the base portion are bent at an angle of less than 180 °, such as an umbrella shape, unlike the T shape, “the base portion is an L shape. The angle between the two surfaces constituting the “base” is considered to be a “corner part of the shape” and is deformed by the bimetal effect as shown in Patent Document 1 and the L-shaped corner part as shown in Non-Patent Document 5. Make a change.

  6D, the base portions are 612 and 614 surfaces, the branch bodies are 613 surfaces and 615 surfaces, and the “angle between the base portion and the branch body” is the branch body 613 surfaces and the branch bodies. There are two on the left and right sides of the 615 plane (total of four: the angle between the 612 plane and the 613 plane, the angle between the 613 plane and the 614 plane, the angle between the 614 plane and the 615 plane, and the angle between the 615 plane and the 612 plane ) The sum of the four angles is 360 ° before the deformation, but the sum of the four angles after the deformation calculated by calculation is not always 360 °. In that case, the angle change is converted into moment force, and the angle after deformation is calculated by force balance calculation.

  In the present invention, “bimetallic warpage deformation” refers to warpage caused by the distribution of shrinkage rate. This includes bow-shaped warp deformation with a concave portion having a large shrinkage rate. Further, “warp deformation at a branching portion” means that a change in an angle formed by a set of a “base portion” and a “branched body” occurs due to a distribution of molding shrinkage strain at the branching portion.

  In the present invention, the “shrinkage ratio” in a specific direction at a certain part means the dimension in the direction of the part of the molded product molded by injection molding or the like and the dimension in the direction of the corresponding part in the mold such as injection molding. Is the value obtained by dividing the difference by the dimensions of the injection mold. In the analysis of injection molding, the “shrinkage ratio” is calculated in consideration of temperature change in the injection molding process, shrinkage caused by PVT characteristics, anisotropy due to orientation, and the like. In general, the shrinkage rate can be obtained for each of the shell elements and solid elements in the analysis.

Examples are given below. FIG. 4H is an example of a shell element. In the case of a shell element, each element 414 has a plurality of calculation points 415 in the thickness direction, and the shrinkage rate is also calculated for each of the plurality of calculation points. When the number of element divisions is small in the thickness direction, a solid element can be calculated like a shell element by providing a plurality of calculation points in the thickness direction like a shell element.
When the “shrinkage rate” is calculated for a larger region, the average shrinkage rate in that region is obtained. The case of averaging in the entire thickness direction is a value generally called molding shrinkage (= molded product dimension / mold dimension).

  In the present invention, the “in-plane direction (thickness direction) shrinkage ratio of the branching portion” represents the branching portion obtained based on the in-plane direction (thickness direction) shrinkage rate of the base portion and the branching portion at the branching portion. In-plane direction (thickness direction) shrinkage rate. For example, there may be a case where an average value or a weighted average value of the shrinkage rate in the in-plane direction (thickness direction) of the base part and the branch part at the branch part or a value obtained from the distribution near the branch part is used. In the case of the shell element illustrated in FIG. 6F, the branching portion is composed of the base element 627 and the branch element 628 with the side 618 constituting the branching portion interposed therebetween. In the case of the solid element illustrated in FIG. It comprises an element 619 constituting the part, an element 627 of the base part, and an element 628 of the branch part. The in-plane direction (thickness direction) shrinkage rate of elements constituting these branch parts may be averaged, or elements adjacent to the elements constituting the branch parts may be further considered.

  In the present invention, the “thickness direction shrinkage ratio” at a certain portion is the difference between the thickness at the corresponding portion of the molded product molded by injection molding and the thickness dimension at the corresponding portion of the injection mold. It is the value divided by the thickness dimension of the mold. For example, FIG. 4G shows an example of a molded product having a T-shaped branch portion in cross section, but the shrinkage rate in the direction as indicated by 407 in FIG. 4G.

  In the present invention, the “in-plane direction shrinkage ratio (in-plane bending direction component)” is a direction in the plane of the base portion or the branch body and is perpendicular to the direction of the intersecting line forming the branch portion. This is the shrinkage factor of the direction (in-plane bending direction) component. For example, FIG. 4G shows an example of a molded product having a T-shaped branch part in the cross section, but the shrinkage rate in the direction as indicated by 408 in FIG. 4G.

  In the present invention, “L-shaped corner structure warpage deformation” and “branch structure warpage deformation” are warpage deformation that occurs when the shrinkage rate in the in-plane direction and the shrinkage rate in the thickness direction are different. For example, when the thickness direction shrinkage rate 407 and the in-plane direction shrinkage rate 408 are different as shown in FIG. 4C, the warp deformation is caused by the mechanism shown in FIG. 4D.

  In the present invention, “shrinkage distribution” means “thickness direction shrinkage distribution” or “in-plane” generated by heat transfer to the mold wall surface, heat generation due to shear with the mold wall surface, mold temperature distribution, etc. "Directional shrinkage distribution". This is considered in the analysis element. In the analysis, data such as displacement and load are stored in the nodes, and stress, strain and shrinkage are stored in the elements. In the case of the shell element, since information in the thickness direction is stored, there are calculation points in the thickness direction. FIG. 4H is an example of a schematic diagram showing the nodes, elements, and calculation points of the shell element. In the case of the shell element of FIG. 4H, the “thickness direction shrinkage distribution” is the distribution of the shrinkage value at the thickness direction calculation point 415 of the element 414. , A distribution of shrinkage rates of a large number of elements 414 existing in the plane.

  In the present invention, the “average value of shrinkage rate in the thickness direction” is the average value of shrinkage rate at the calculation point 415 in the thickness direction. As the “average value”, an average value at all calculation points in the thickness direction may be used, or values of some calculation points among a plurality of calculation points may be regarded as an average value. Of course, one central point in the thickness direction may be used as a partial calculation point.

  In the present invention, the “flow history” is a history of a flow rate and an inflow direction to each branch body and the base portion ahead of each branch body in the injection molding filling analysis with respect to the entire flow rate at the branch site. For example, the flow rate and flow direction history of the flow rate flowing out from the base portion element 308 toward the corner portion in FIG. 3B and the amount flowing out from the base portion element 308 to the branching element 309 are shown. Here, the history may be a set of values at each point of time that changes over time, or an average or integration within a predetermined period.

  In the present invention, the “filler” refers to a filler for enhancing physical properties such as rigidity, strength, heat resistance, insulation, and corrosion resistance of a molded product. For example, reinforcing fibers such as glass fiber and carbon fiber, inorganic substances such as talc, mica, calcium carbonate, alumina, clay, diatomaceous earth, asbestos, barium sulfate, titanium oxide, caryon, wet or dry silica, colloidal silica, calcium phosphate, zirconia That's it.

  In the present invention, the “distance from the branching portion to the tip of the branching body” refers to the direction perpendicular to the line of intersection between the base portion forming the branching part and the branching body from the branching portion within the plane of the branching body. It is the distance to the tip.

  FIG. 6F shows an example of a shell element having a T-shaped cross section, and FIG. 6G shows an example of a solid element having a T-shaped cross section. The “distance from the branch portion to the tip of the branch body” is the dimension 620 in FIG. 6F for the shell element shown in FIG. 6F and the dimension 620 in FIG. 6G for the solid element shown in FIG. 6G. In FIG. 6F, the height of the part excluding the base part from the molded product is used, but considering the neutral surface (surface in the thickness direction center), the height of the part excluding the base part from the molded product is used. You may add what added the length of the half of the thickness of a base part.

  However, if there is no shape that becomes the tip in the direction perpendicular to the branch site in the plane of the branch body from the branch site, such as an annular shape or an H-shaped shape, from the branch site to the part that bends in an L shape The distance or the distance from the branch site to the portion that branches into two or more branches is defined as “distance from the branch site to the tip of the branch body”.

  FIG. 6H is an example of an annular shape, and FIG. 6I is an example of an H-shaped shape. In the case of a shape that gradually bends as shown in this figure, the “distance from the branch site to the tip of the branch body” is the direction vector orthogonal to the branch site in the plane of the branch body from the branch site and the direction vector at the branch site. The distance to the portion where the angle 629 formed by the above becomes 45 ° or more. In the case of FIG. 6H, this is the distance h (620). In addition, the distance from the branch site to branching into two or more branches is the distance h (620) in FIG. 6I.

  According to the present invention, although it is a simple calculation method, the shrinkage rate in each direction and the prediction accuracy of warpage in the injection molding analysis are improved, and the development cost of the molded product can be suppressed and the development period can be shortened.

  Embodiments of an injection molding analysis method and an injection molding analysis apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 7 is a block diagram showing a configuration of an example of the embodiment of the present invention. In the present embodiment, as shown in FIG. 7, (700) is a computer such as a computer or workstation, (701) is a keyboard, (702) is a mouse, (703) is a display, and (704) is an auxiliary storage device. is there. The auxiliary storage device (704) includes a hard disk device, a tape, an FD (flexible disk), an MO (magneto-optical disk), a PD (phase change optical disk), a CD (compact disk), and a DVD (digital versatile disk). ) Etc., removable media such as USB (Universal Serial Bus) memory, memory cards, etc. can also be used.

  The auxiliary storage device 704 includes a program 705 for analyzing an injection molding process, a shape data for injection molding analysis 706 or a program 705 for creating shape data for injection molding analysis, viscosity, PVT characteristics, elastic modulus, Poisson's ratio. Further, molding property data 707 such as linear expansion coefficient and molding condition data 708 such as set temperature, set pressure, set speed, and set time are stored.

  A computer 700 such as a computer or a workstation includes data reading means 709 that can read a program 705, shape data 706, molded article property data 707, molding condition data 708, and the like from the auxiliary storage device 704. Also, an injection molding process analyzing means 710 for analyzing the injection molding process, a shrinkage rate calculating means 711, a total warp deformation analyzing means 715, a thickness calculating means 712, a distance calculating means 713 from the branch site to the tip of the branched body, a flow rate calculating means 714, a warp deformation amount calculating means 715, a shape determining means 716 for classifying the shape data 706 into one of a flat plate portion, an L-shaped corner portion, and a branching portion, and an output means 717. The warp deformation amount analysis means 715 includes a bimetal warp deformation amount calculation means 718, an L-shaped corner structure warpage deformation amount calculation means 719, a branch structure warpage deformation amount calculation means 720, an L-shaped corner portion total warp analysis means 721, and a branch portion. It comprises total warp analysis means 722.

  The shape data 706 can be created by a general-purpose injection molding analysis preprocessor such as UNV format of “I-DEAS (registered trademark)” manufactured by UG Corporation, and is expressed by shell elements, solid elements, and the like. Of course, the format of the shape data 706 is not limited as long as the format of the file storing the model data is data in which nodes, elements, element properties, material properties, and the like are described.

  FIG. 8 is an example of a flowchart of the first to third embodiments of the present invention. Hereinafter, steps that are not substantially different from those in the flowchart of FIG. 2 may be denoted by the same reference numerals as those in FIG.

  The flowchart of FIG. 8 will be described below.

  CAD shape data is read into a computer such as a computer or a workstation, or input is performed using a keyboard or mouse (200). Similarly, resin physical property data and molding conditions are read or input (201, 202). The injection molding process analysis 203 is performed based on these data.

  The injection molding process analysis 203 carries out a filling process analysis 204, a pressure holding / cooling process analysis 205, a shrinkage rate calculation 206, and an orientation analysis 208, as in the analysis method shown in the flow of FIG.

  In addition, in order to perform the branch structure warp deformation amount analysis 807, a wall thickness calculation 801, a distance calculation 802 to the branch body tip, and a flow rate history calculation 803 are performed.

  Unlike conventional methods, the warpage deformation amount analysis classifies the shape into three parts, that is, a plane portion, an L-shaped corner portion, and a branch portion by shape discrimination 804, and performs warpage deformation amount analysis for each shape (in the flat plate portion, Bimetal warp deformation amount analysis 805 is performed. In the L-shaped corner portion, in addition to the bimetal warp deformation amount analysis 805, an L-shaped corner structure warp deformation amount analysis 806 is performed, and the L-shaped corner portion total warpage is integrated. The deformation amount analysis 808 is performed, and the bifurcation warpage deformation amount analysis 805 is performed in addition to the bimetal warpage deformation amount analysis 805, and the branch portion total warpage deformation amount analysis 809 for integrating them is performed at the branch portion), and finally Then, a warp deformation analysis 810 for integrating them is performed and output 209. Hereinafter, the branch structure warp deformation analysis 807 by the branch structure warp deformation amount calculation means 720 will be described.

  In the first embodiment, the branch structure warpage deformation amount calculation means 720 includes the base portion thickness 622 (element thickness data in the case of a shell element) and the branch thickness 621 calculated at step 801. (In the case of a shell element, the element thickness data), the arithmetic average of the in-plane direction shrinkage 626 of the base portion and the in-plane direction shrinkage rate 624 of the base portion, the thickness direction shrinkage rate 625 of the base portion, and the thickness of the branch portion The thickness direction average value (in-plane bending direction component) Sx of the in-plane direction shrinkage rate of the branching portion, which is represented by the arithmetic average of the thickness direction shrinkage rate 623, the thickness direction average value Sz of the thickness direction shrinkage rate, the base The angle 905 (α) formed between the base and the branch body is substituted into the formula (4) or (5), and the change amount Δα between the base portion after the contraction and the branch body or the base portion after the contraction branches. The angle β formed by the body is calculated. Since the base surface exists on the opposite side with the branch body interposed therebetween, the same processing is performed between the base surface and the branch body existing on the opposite side. When there are many branch bodies, the same processing is performed between the base portion and each branch body.

  Expression (4) is an expression for deriving the amount of change in the angle after deformation from the angle between the base part before the deformation and the branch body, and Expression (5) is based on the angle between the base part before the deformation and the branch body after the deformation. Equations (4) and (5) have the same first-order terms in the case of Taylor expansion, and are substantially equivalent both physically and mathematically.

  Equations (4) and (5) show that the thickness 621 of the branch body (element thickness data in the case of a shell element) is smaller than the thickness 622 (element thickness data in the case of a shell element). This is an expression that incorporates the knowledge that the presence of the branching body has a small influence on the amount of change in the angle at the corner when the condition is small, and can provide high accuracy when such a condition is satisfied. Equation (4) is obtained by substituting Equation (2) for the angle variation Δα of the L-shaped corner portion after shrinkage in Non-Patent Document 5 with parameters for the thickness d2 of the base portion and the thickness d1 of the branch body ( exp (AB × (d1 / d2)) is added as a correction term. Equation (5) is the thickness of the base portion in Equation (3) for determining the angle β of the L-shaped corner portion after contraction. d2, the parameter of the wall thickness d1 (exp (AB × (d1 / d2))) is added as a correction term, that is, the amount of warpage is determined by the angle between the base part and the branch part and the base part The amount of warp deformation caused by the branch structure is obtained based on the ratio of the thickness of the slab to the thickness of the branch body.

  The bimetal warp deformation amount calculation means 718 calculates 805 the amount of warp deformation caused by the bimetal effect by calculating the balance of stress from the shrinkage rate distribution at the bifurcation site.

  Then, by executing the stress balance calculation again from the output of the branch structure warp deformation amount analysis 807 by the branch structure warp deformation amount calculation means 720 and the output of the bimetal warp deformation amount analysis 805 by the bimetal warp deformation amount calculation means 718, the total of the branch parts is calculated. A warp deformation amount analysis 809 is performed, and the result is output as a warp deformation of a branch portion in consideration of the warp deformation caused by two types of causes.

  The warp deformation amount calculation means 715 outputs the warp deformation amount of the flat plate portion calculated in the same manner as the bifurcation part (calculated by bimetal warp deformation amount analysis 805), and the warp deformation amount output of the L-shaped corner part (bimetal warp deformation amount analysis 805). In addition to the L-shaped corner structure warpage deformation amount analysis 806, the L-shaped corner portion total warpage deformation amount analysis 808 is performed, and the warpage deformation amount output of the branch portion is used to calculate the balance of stress in the entire molded product. The warpage deformation amount analysis 810 of the entire molded product is performed.

  In the second embodiment, the branch structure warpage deformation amount calculation means 720 calculates the thickness 622 of the base portion (the element thickness data in the case of a shell element) and the thickness of the branch body calculated in step 801. 621 (element thickness data in the case of a shell element), the distance 620 from the branching site to the tip of the branch body calculated in step 802, the in-plane direction shrinkage ratio 626 of the base portion, and the in-plane direction shrinkage ratio 624 of the branch body Thickness direction average value of the in-plane direction shrinkage rate of the branch portion, which is the arithmetic average of the arithmetic average, the thickness direction shrinkage rate 625 of the base portion, and the thickness direction shrinkage rate 623 of the branch body (in-plane bending direction component) ), The thickness direction average value of the contraction rate in the thickness direction, and the angle 905 formed by the base portion and the branch body are substituted into the formula (6) or the formula (7), and the change of the angle formed by the base portion and the branch body after the contraction Amount Δα or branch and base after shrinkage The angle β formed by the body is calculated. Since the base surface exists on the opposite side with the branch body interposed therebetween, the same processing is performed between the base surface and the branch body existing on the opposite side. When there are many branch bodies, the same processing is performed between the base portion and each branch body.

  Expression (6) is an expression for deriving the amount of change in the angle after deformation from the angle between the base part before the deformation and the branch body, and Expression (7) is based on the angle between the base part before the deformation and the branch body after the deformation. Equation (6) and Equation (7) are almost equivalent.

  In the equations (6) and (7), when the thickness d1 of the branch body is smaller than the thickness d2 of the base portion, the influence of the branch body on the change amount Δα of the angle at the branch site is small. When the distance 620 from the branch part to the tip of the branch body is smaller than the thickness 621 of the branch body, it incorporates the knowledge that the branch body has little influence on the angle change amount Δα at the corner, It is an expression that can obtain high accuracy when such a condition is satisfied. Equation (6) is the equation (2) for determining the angle change Δα of the L-shaped corner after contraction. The thickness d2 of the base portion, the thickness d1 of the branch body, and the distance from the branch site to the tip of the branch body The distance h parameter (exp (AB × (d1 / d2)), (exp (DE × (h / d1))) is added as a correction term. Equation (7) is the L-shaped shape after contraction. Equation (3) for determining the angle β of the corner part is a parameter (exp (AB × (d1 / d2)) for the thickness d2 of the base part, the thickness d1 of the branching body, the distance h from the branching site to the tip of the branching body, (Exp (DE × (h / d1)) is added as a correction term.In other words, the amount of warpage deformation is the angle between the base part and the branch body, the thickness of the base part, and the thickness of the branch body. The amount of warp deformation caused by the branched structure is obtained based on the ratio, the ratio of the branched part to the tip of the branched body, and the ratio of the branched body thickness.

  The bimetal warp deformation amount calculation means 718 obtains the deformation amount of the warp caused by the bimetal effect as in the first embodiment.

  Then, by executing the stress balance calculation again from the output of the branch structure warp deformation amount analysis 807 by the branch structure warp deformation amount calculation means 720 and the output of the bimetal warp deformation amount analysis 805 by the bimetal warp deformation amount calculation means 718, the total of the branch parts is calculated. A warp deformation amount analysis 809 is performed, and the result is output as a warp deformation of a branch portion in consideration of the warp deformation caused by two types of causes.

  The warp deformation amount calculation means 715 outputs the warp deformation amount of the flat plate portion calculated in the same manner as the bifurcation part (calculated by bimetal warp deformation amount analysis 805), and the warp deformation amount output of the L-shaped corner part (bimetal warp deformation amount analysis 805). In addition to the L-shaped corner structure warpage deformation amount analysis 806, the L-shaped corner portion total warpage deformation amount analysis 808 is performed, and the warpage deformation amount output of the branch portion is used to calculate the balance of stress in the entire molded product. The warpage deformation amount analysis 810 of the entire molded product is performed.

  In the third embodiment, the thickness 622 (element thickness data in the case of a shell element) and the branch thickness 621 (element thickness in the case of a shell element) at a branching site calculated in step 801. Thickness data), the flow history calculated in step 803, the arithmetic average of the in-plane direction shrinkage 626 and the in-plane direction shrinkage 624 of the base, the thickness direction shrinkage 625 of the base, the thickness of the branch The average value (in-plane bending direction component) of the in-plane direction shrinkage rate of the branch portion, the average value of the thickness direction shrinkage rate, the angle 905 formed by the base portion and the branch body, with the arithmetic average of the direction shrinkage rate 623 as a representative value. By substituting into Equation (8) or Equation (9), the amount of change Δα of the angle of the corner portion after contraction or the angle β of the corner portion after contraction is calculated. Since the base surface exists on the opposite side with the branch body interposed therebetween, the same processing is performed between the base surface and the branch body existing on the opposite side. When there are many branch bodies, the same processing is performed between the base portion and each branch body.

  Expression (8) is an expression for deriving the amount of change in the angle after deformation from the angle between the base part before the deformation and the branch body, and Expression (9) is based on the angle between the base part before the deformation and the branch body after the deformation. Equation (8) and Equation (9) are almost equivalent.

  Here, the flow history will be described in detail. The flow history is calculated in all of the branch portions, and taking FIG. 3B as an example, the flow history is calculated for the base portion element 308 and the branch body element 309 adjacent to the corner portion. When attention is paid to one of the elements 308 of the base part adjacent to the branch site, there are four base part elements and one branch element in the periphery. In the analysis of the filling process, the sum of the flow rates flowing in and out of each element can be calculated. In the injection molding and filling analysis, each branch body and the base part ahead of it are compared with the total flow rate at the branch site. The history of flow rate and inflow direction is called flow history.

  Equation (8) is the equation (2) for calculating the amount of change in the angle of the L-shaped corner portion after contraction. The thickness of the base portion, the thickness of the branch body, and the flow history parameters (exp (AB × (d1 / d2)), (exp (FH × (∫G (t) Vcdt / ∫vmagdt)) is added as a correction term, and equation (9) is for the corner of the L-shaped shape after contraction. Equation (3) for calculating the angle is based on the thickness of the base part, the thickness of the branch body, and the flow history parameters (exp (AB × (d1 / d2)), (exp (FH × (∫G (t) Vcdt / ∫ vmagdt)) is added as a correction term, that is, the amount of warpage is the angle between the base and the branch, the ratio of the thickness of the base and the branch, and the flow history of the branch. Based on the above, the amount of warp deformation caused by the branch structure is obtained.

  The bimetal warp deformation amount calculation means 718 obtains the deformation amount of the warp caused by the bimetal effect as in the first embodiment.

  Then, by executing the stress balance calculation again from the output of the branch structure warp deformation amount analysis 807 by the branch structure warp deformation amount calculation means 720 and the bimetal deformation amount analysis 805 output by the bimetal warp deformation amount calculation means 718, the branch portion total warpage is performed again. A deformation amount analysis 809 is performed, and the result is output as a warpage deformation of a branch portion in consideration of warpage deformation caused by two types of causes.

  The warp deformation amount calculation means 715 outputs the warp deformation amount of the flat plate portion calculated in the same manner as the bifurcation part (calculated by bimetal warp deformation amount analysis 805), and the warp deformation amount output of the L-shaped corner part (bimetal warp deformation amount analysis 805). In addition to the L-shaped corner structure warpage deformation amount analysis 806, the L-shaped corner portion total warpage deformation amount analysis 808 is performed, and the warpage deformation amount output of the branch portion is used to calculate the balance of stress in the entire molded product. The warpage deformation amount analysis 810 of the entire molded product is performed.

  Here, the exponent part of the equations (4) to (9), which is also used in the branch structure warp deformation amount calculation means 720, will be described. A function as shown in Expression (10) is called a sigmoid function, and an S-shaped curve having F (X) = 0 and F (X) = 1 asymptotic lines is drawn. Equations (4) to (9) substitute the function of the thickness of the base part, the thickness of the branch body, the distance from the branch site to the tip of the branch body, and the flow history into the variable X of the sigmoid function. Is a mathematical expression. Instead of this sigmoid function, a HILL function as shown in the equation (11) with F (X) = 0 and F (X) = 1 asymptotic lines may be used as in the sigmoid function. . When the HILL function is used, the function of the thickness of the base part, the thickness of the branching body, the distance from the branching part to the tip of the branching body, and the flow history is substituted into the variable X, and the influences thereof are expressed numerically. When the constant k is increased or the constant n is decreased, the change to F (X) = 0 and F (X) = 1 becomes gradual. The HILL function is characterized in that the change near F (X) = 0 is steeper than the change near F (X) = 1. By using these functions, the thickness of the base part, the thickness of the branching body, the distance from the branching part to the tip of the branching body, and the flow history may or may not affect the corner warp. Can be expressed numerically continuously. The functions having the characteristics of the asymptotic line having the two extreme values as described above are treated as mathematically equivalent in the present invention. The case where mathematical corrections relating to the discrete handling of numerical values due to the use of a digital computer are added is also mathematically equivalent.

  Hereinafter, a method for creating these constants and variables from A to H will be described in detail. These constants are parameters obtained by experiments and the like.

  For the creation of constants and variables from A to H, comparative evaluation was performed on the amount of change in the angle after contraction by experiment and analysis, and the angle of inclination of the corner portion by analysis was expressed by equations (4) to (9). Use to match the actual measurement. The evaluation mold may be any of T-type, Y-type, umbrella-type, X-type, and star-type as long as it has a branched portion, but in order to simplify the evaluation, the T-type shown in FIG. 9A Good shape. FIG. 9A is a perspective view showing an example of a T-shaped molded product shape molded by the evaluation mold of the present invention, and FIG. 9B is a T-shaped molding molded by the evaluation mold of the present invention. It is sectional drawing which shows an example of goods, and sectional drawing which showed typically the calculation method of the angle of the base | substrate part before and behind shrinkage | contraction and a branching body.

  In the case of the T-shape, the branch body is a rib portion, the branch body thickness is the rib thickness, and the distance from the branch site to the branch body tip is the rib height. The angle α between the base portion and the branch body is an angle 905 between the base portion and the rib shown in FIG. 9B, and the angle β between the base portion and the branch body after contraction is an angle 906 between the base portion and the rib. It is. The amount of change in the angle between the base part and the branching body is the difference between the angle 905 and the angle 906. If the amount of change in the angle between the base and the rib is different on the left and right sides of the rib, a representative value such as an average value or a maximum value may be used. If the size is different, it may be classified as an inflow side angle and an outflow side angle.

  The mold has a nested structure, and the thickness of the base part, the thickness of the rib, and the height of the rib are variable, and the influence of the thickness of the base part, the thickness of the rib, and the height of the rib on the tilt angle of the branching part To evaluate.

  It is preferable to perform two gate positions: a position 907 where the filling direction is perpendicular to the rib and a position 908 where the filling direction is parallel. As for the shape condition, it is preferable to set the thickness of the base portion and the thickness of the rib between 1 mm and 4 mm. The height of the rib is preferably set between 3 mm and 8 mm. In addition, it is preferable to set two molding conditions, respectively. However, conditions that are considered to have a small influence may be omitted. Multiplying all cases results in an unrealistic number of experiments, so it is better to use an experimental design.

  Moreover, when analyzing using Formula (8) or Formula (9), the flow volume history of the material which flows into a branch body from a base part is calculated.

  With respect to the thickness of the base portion of the evaluation mold, the thickness of the rib, the mold shape condition of the height of the rib, and the flow history, the evaluation position may be arbitrary, but the center position in the thickness direction may be a representative point.

  FIG. 10A is a diagram showing an example of a result obtained by actually measuring the amount of change in angle after shrinkage with respect to the thickness of the rib / thickness of the base portion of the evaluation mold of the present invention, and FIG. FIG. 10C is a diagram showing an example of a result obtained by actually measuring the amount of change in angle after shrinkage with respect to the height of the rib / the thickness of the base portion of the evaluation mold of the present invention. It is a figure which shows an example of the result at the time of actually measuring the variation | change_quantity of the angle after shrinkage | contraction with respect to a flow history about this evaluation metal mold | die. The actual measurement result and the analysis result are graphed as shown in FIGS. 10A to 10C, and the change amount of the angle between the base portion and the branch body in the analysis is matched with the change amount of the angle between the base portion and the branch body in the measurement. Determine the constants and variables from A to H. As an example, a method for determining C from constants A will be described with reference to FIG. 10A. The thickness of the base of the actual measurement and analysis and the thickness of the rib should be set to 9 cases or more as much as possible from thin to thick. Specifically, the thickness of the base portion and the thickness of the ribs are 1 mm, 2 mm, and 3 mm, respectively, and the three levels are combined to obtain a total of 9 levels. For each of the experimental results and analysis results, the horizontal axis (rib wall thickness / base thickness) and the vertical axis are plotted as a tilt angle after contraction. The analysis result may be any value as an initial value. For example, A = 1, B = 1, C = 1, etc. When each is graphed, both the experimental result and the analysis result may change such that the tilt angle changes abruptly. In that case, A, B, and C are changed using a least square method or the like so that the inflection point of the analysis result is close to the inflection point of the measurement result.

  The constants and variables other than the constants A to C are determined in the same manner as the method for determining the constants A to C. When determining the constants A, B, C, D, and E using FIG. 10B, set a level of 9 cases or more for the thickness of the base portion and the height of the rib, and set the horizontal axis of the graph (the height of the rib). The thickness of the base portion) and the vertical axis are plotted as the tilt angle after contraction, and the constant is changed so that the analysis result matches the actual measurement. When determining the constants A, B, C, F, H, and the variable G (t) using FIG. 10C, the base part thickness, rib thickness, and rib height should be at least three cases. Set. In order to minimize the experimental level, an experimental design is used. Then, for each of the experimental results and the analysis results, the horizontal axis is a value obtained by an expression indicating the flow history of the branch portion, and the vertical axis is graphed as the amount of change in the tilt angle after contraction. As for the value of the horizontal axis, since it is difficult to measure the actual measurement result, the value obtained from the analysis is used.

  The measured angle change amount of the branch part is the sum of the deformation amount due to the bimetal effect at the branch part and the warp deformation amount at the branch part, and the sum of the warp deformation amount due to the bimetal effect of the flat plate portion following the branch part (total warpage). Deformation amount). Therefore, when determining constants and variables by comparison between analysis and actual measurement, the angle change amount of the bifurcation part is also calculated in the same way by calculating the total warpage deformation, and the angle at the same position as the actual measurement position. Measure the amount of change.

[Example 1]
By combining a T-shaped molded product (width 50 mm, depth 50 mm) shown in FIG. 9A with a mold insert, the thickness of the base portion is 1 mm, 2 mm, and 3 mm, and the rib thickness is 1 mm, 2 mm, and 3 mm. The height of the rib was set to 1 mm, 3 mm, and 5 mm, and a total of 27 shapes were molded by injection molding. Polyamide 6 resin (containing 30% by weight of reinforced glass fiber) is used as the material of the molded product. The molding conditions are a resin temperature of 260 ° C., a mold temperature of 80 ° C., a resin filling time of 1 second, a holding pressure of 50 MPa, and a holding pressure. The time was 10 seconds and the cooling time was 10 seconds. There were two gate positions: a position 907 where the flow was perpendicular to the ribs and a position 908 where the flow was parallel.

  The molded product taken out from the mold is cooled in a dry state for 2 days, three warp reference points 902 shown in FIG. 8A are fixed, and ribs are measured by a precision three-dimensional measuring instrument (Bright-STRATO 776 manufactured by Mitutoyo Corporation). The tilt angle after contraction of the cross-section 909 perpendicular to the rib was measured at the position of the central portion in the longitudinal direction. As for the analysis result, as with the actual measurement, three warp reference points shown in FIG. 9A were fixed, and the tilt angle after contraction was calculated.

  FIG. 11A is a diagram showing the results of actual measurement and analysis of the amount of change in angle after shrinkage with respect to the rib thickness / base thickness for the evaluation mold of the present invention.

For Equation (4), constant A is set to 17, B is set to 21, C is set to 0.8 so that the corner tilt angle is matched with the measurement result and the analysis result, and the corner portion is expressed as Equation (4). The amount of change in the angle 905 formed by the base part and the rib (branched body) is calculated from the inward shrinkage rate and the thickness direction rate shrinkage, the base part thickness, and the rib thickness, and the horizontal axis (rib thickness) / Thickness of the base part), the vertical axis as the tilt angle after shrinkage (the sum of the angle changes generated by the bimetal effect, the amount of change between the base part and the rib (branched body) obtained from the formula (4)), The measurement results and analysis results are summarized as shown in FIG. 11A.
[Comparative Example 1]
Based on the method of Non-Patent Document 5, with respect to the branch part, the angle between the two surfaces sandwiching the corner branch part is changed before and after the contraction due to the shrinkage in the in-plane direction and the shrinkage in the thickness direction as shown in Equation (2). By calculating, the tilt angle at the corner after contraction was calculated, and the analysis results were obtained from the change in the tilt angle after contraction of the vertical axis and the wall thickness of the horizontal axis ribs / base part (formula (2)) The amount of change in the angle formed by the base portion and the rib (branch body) can be summarized as the sum of the change in angle caused by the bimetal effect) as shown in FIG. 11A.
[Example 2]
FIG. 11B is a diagram showing the results of actual measurement and analysis of the amount of change in angle after shrinkage with respect to the rib height / base wall thickness for the evaluation mold of the present invention.

For equation (6), the constant A is 17, the B is 21, the C is 0.8, the D is 18, and the E is 20 so that the angle of the corner falls is matched with the actual measurement result and the analysis result. The amount of change in the angle 905 between the base part and the rib (branched body) is calculated from the in-plane direction shrinkage rate and the thickness direction rate shrinkage, the base part thickness, and the rib height as shown in equation (6). The horizontal axis is (rib height / base thickness), and the vertical axis is the tilt angle after contraction (the amount of change in the angle between the base and rib (branch) obtained from equation (6)) As the sum of the generated angle changes), the results of measurement and analysis are summarized as shown in FIG. 11B.
[Comparative Example 2]
The analysis results of Comparative Example 1 are shown in FIG. 11B when the horizontal axis is (rib thickness / base thickness) and the vertical axis is the amount of change in the tilt angle after contraction.
[Example 3]
FIG. 11C is a diagram showing the results when the amount of change in the angle after contraction with respect to the flow history is measured and analyzed for the evaluation mold of the present invention.

For equation (8), constant F is set to 16, corner is set to 20, C is set to 0.8, and G is set to 1 so that the corner tilt angle is matched with the measurement result and the analysis result. From the in-plane direction shrinkage rate and the thickness direction rate shrinkage, the flow amount of the branch part, the change amount of the angle 905 formed by the base part and the rib (branch body) is calculated, and the horizontal axis is the flow history of the corner part, When the vertical axis is the tilt angle after contraction (the sum of the angle changes caused by the bimetal effect, the amount of change between the base and rib (branched body) obtained from equation (8)), As shown in FIG. 11C.
[Comparative Example 3]
The analysis results of Comparative Example 1 are shown in FIG. 11C when the horizontal axis represents the flow history and the vertical axis represents the amount of change in the tilt angle after contraction.
[Example 4]
FIG. 12A is a view of a resin molded product having four ribs (width 2 mm, length 80 mm, height 2 mm, spacing between ribs 20 mm) on a flat plate (width 100 × 100 mm, wall thickness 4 mm). Using polyamide 6 resin (containing 30% by weight of reinforced glass fiber), molding conditions are resin temperature 260 ° C., mold temperature 80 ° C., resin filling time 1 second, holding pressure 50 MPa, holding pressure 10 seconds, cooling The time was 10 seconds. The gate was the central portion 1201 of the side of the flat plate portion (side parallel to the rib).

  Molding was carried out under these conditions, and supported by reference points (1202, 1203, 1204). The deformation after shrinkage was measured, and as a result, the rib was recessed as shown in FIG.

On the other hand, the shape shown in FIG. 12A is modeled by a shell element, and according to the flowchart shown in FIG. 8, filling process analysis, pressure holding / cooling process analysis, orientation analysis, shrinkage rate calculation, wall thickness calculation are performed. Based on the calculated coefficient, the constant A is set to 17, B is set to 21, C is set to 0.8 for the formula (4), and the branch portion is an angle formed by the base portion and the rib (branched body) based on the formula (4). The amount of change was calculated. When the deformation after contraction was analyzed by supporting at the reference points (1202, 1203, 1204), the rib was recessed as shown in FIG.
[Example 5]
The shape shown in FIG. 12A is modeled by a shell element, and according to the flow chart shown in FIG. 8, a filling process analysis, a pressure holding / cooling process analysis, an orientation analysis, a shrinkage rate calculation, a wall thickness, and a distance to a branch body tip are calculated. Based on the coefficient calculated in Example 2, with respect to the equation (6), the constant A is 17, B is 21, C is 0.8, D is 18, E is 20, and the branch site is the equation (6) Based on this, the amount of change in the angle between the base part and the rib (branch body) was calculated. When the deformation after contraction was analyzed by supporting it at the reference points (1202, 1203, 1204), the deformation was concaved by 0.12 mm with the rib side recessed as shown in FIG. 12B.
[Example 6]
The shape shown in FIG. 12A is modeled by a shell element, and according to the flow chart shown in FIG. 8, filling process analysis, pressure holding / cooling process analysis, orientation analysis, shrinkage rate calculation, and flow history calculation are performed. Based on the coefficient, for formula (8), constant F is 16, H is 20, C is 0.8, G is 1, and the branch part is based on formula (8) and the base portion and rib (branched body) The amount of change in the angle formed was calculated. When the deformation after contraction was analyzed by supporting it at the reference points (1202, 1203, 1204), the deformation was concaved by 0.12 mm with the rib side recessed as shown in FIG. 12B.
[Comparative Example 4]
The shape shown in FIG. 12A is modeled by a shell element, and as shown in Non-Patent Document 5, according to the flow diagram shown in FIG. 2, a filling process analysis, a pressure holding / cooling process analysis, an orientation analysis, and a shrinkage rate calculation are performed. Based on 2) and the bimetal effect, the tilt angle at the branch site after contraction was calculated. When the deformation after contraction was analyzed by supporting at the reference points (1202, 1203, 1204), the rib side was recessed as shown in FIG.
[Summary]
Conventionally, it has been said that there is no problem if qualitative warpage can be evaluated by analysis of injection molding analysis. However, since the product development period is short in recent years, the error from the actual measurement can be kept within about ± 20%. It is desired to perform a quantitative evaluation and shorten the mold production period, and an analysis that causes an error of 200% or more as in Comparative Example 4 is insufficient as a prediction accuracy of the analysis. It is. As shown in Table 1, the error rate is 8.3% in Example 4, 0% in Example 5 and Example 6, and 283% in Comparative Example 4, and the example is compared to Comparative Example 4. The warpage prediction accuracy is greatly improved.

  INDUSTRIAL APPLICABILITY The present invention is not limited to use as an analysis method and apparatus that can predict the shrinkage rate and warpage of an injection molded product with high accuracy, but also evaluates the physical properties of the injection molded product, and the injection molded product inside the injection mold. Although it can be applied to behavior evaluation and the like, the application range is not limited to these.

It is a schematic diagram which shows an example of the injection molding machine for implementing the injection molding of the resin product. It is a schematic diagram which shows an example of a resin filling process among the injection molding processes of a resin product. It is a schematic diagram which shows an example of the resin holding | maintenance process among the injection molding processes of a resin product. It is a schematic diagram which shows an example of the resin cooling process among the injection molding processes of a resin product. It is a schematic diagram which shows an example of a mold release process (mold opening) among the injection molding processes of a resin product. It is a flowchart which shows an example of a structure of the conventional injection molding process analysis. It is a perspective view which shows an example of the method of replacing a certain shape of a three-dimensional volume with a two-dimensional plane (shell element). It is the perspective view which showed an example of the filling analysis result when filling a molded article material in the shape (solid element) with a three-dimensional volume, and a two-dimensional plane (shell element). An example of the results of analysis using a three-dimensional volume shape (solid element) and a two-dimensional plane (shell element) for an example of the contraction behavior of a shape that is a small protrusion relative to the base part is there. It is a perspective view of an example of the curvature deformation | transformation behavior of a corner part when the metal mold | die surface inside a corner part of L-shape is high temperature. It is a perspective view which shows an example of the curvature deformation | transformation behavior at the time of analyzing using a shell element about the case where the metal mold | die surface inside a corner part of L-shape is high temperature. It is a perspective view which shows an example of the curvature deformation | transformation behavior of a corner part when it analyzes with a solid element about the case where a thickness direction shrinkage rate is larger than an in-plane direction shrinkage rate (in-plane bending direction component). It is sectional drawing which shows typically the curvature deformation behavior of a corner part about the case where a thickness direction shrinkage rate is larger than an in-plane direction shrinkage rate (in-plane bending direction component). It is a perspective view which shows the curvature deformation behavior of the corner part when analyzing by a shell element about the case where a thickness direction shrinkage rate is larger than an in-plane direction shrinkage rate (in-plane bending direction component). The perspective view which shows an example of the curvature deformation behavior of a corner part when the element division is insufficient and when the element division is insufficient when the contraction rate in the thickness direction is larger than the contraction rate in the in-plane direction (in-plane bending direction component) It is. It is a perspective view which shows an example of the molded article which has a T-shaped branch part in a cross section. It is an example of the schematic diagram which shows the node of a shell element, an element, and a calculation point. It is an example of the figure which shows the calculation method of the angle after shrinkage | contraction of the nonpatent literature 5, and is sectional drawing which shows the shape before shrinkage | contraction and the shape after shrinkage | contraction of the L-shaped corner curved surface. It is an example of the figure which shows the calculation method of the angle after shrinkage | contraction of a nonpatent literature 5, Comprising: The 2 surface which comprises the L square shape which shows the shape before shrinkage | contraction of the corner part of a L-shaped corner and the shape after shrinkage | contraction It is sectional drawing of a half shape on the surface which equally divides | segments an angle. It is the figure which showed an example of the shape of a molded article with a T-shaped branch part by a shell model. It is the figure which showed an example of the shape of a molded article which has a Y-shaped branch part. It is the figure which showed an example of the shape of a molded article which has an umbrella-shaped branch part. It is the figure which showed an example of the shape of a molded article which has an X-shaped branch part. It is the figure which showed an example of the shape of a molded article which has a star-shaped branch part. About the branch shape, taking the T-shaped shape as an example, the thickness direction shrinkage rate, in-plane direction shrinkage rate, angle between the base part and the branch body, and the distance from the branch site to the branch body tip are schematically shown in the shell model. It is shown. About the branch shape, taking the T-shaped shape as an example, the thickness direction shrinkage rate, in-plane direction shrinkage rate, angle between the base part and the branch body, and the distance from the branch site to the branch body tip in the solid model It is shown. It is a perspective view which shows an example of the shape where a branch body front-end | tip is cyclic | annular shape. It is a perspective view which shows an example of the shape whose branch body front-end | tip is a branch body. It is a block diagram which shows the structure of an example of embodiment of this invention. It is a flowchart of an example of embodiment of this invention. It is a perspective view which shows an example of the T-shaped molded product shape shape | molded with the evaluation metal mold | die of this invention. It is sectional drawing which shows an example of the T-shaped molded product shape | molded with the evaluation metal mold | die of this invention, and sectional drawing which showed typically the calculation method of the angle of the base | substrate part before and behind shrinkage | contraction and a branching body. It is a figure which shows an example of the result at the time of actually measuring the variation | change_quantity of the angle after shrinkage | contraction with respect to the thickness of a rib / the thickness of a base | substrate part about the evaluation metal mold | die of this invention. It is a figure which shows an example of the result at the time of actually measuring the variation | change_quantity of the angle after shrinkage | contraction with respect to the height of a rib / thickness of a base | substrate part about the evaluation metal mold | die of this invention. It is a figure which shows an example of the result at the time of actually measuring the variation | change_quantity of the angle after shrinkage | contraction with respect to the flow history about the evaluation metal mold | die of this invention. It is a figure which shows the result at the time of actually measuring and analyzing the variation | change_quantity of the angle after shrinkage | contraction with respect to the thickness of a rib / thickness of a base | substrate part about the evaluation metal mold | die of this invention. It is a figure which shows the result at the time of actually measuring and analyzing the variation | change_quantity of the angle after shrinkage | contraction with respect to the height of a rib / thickness of a base | substrate part about the evaluation metal mold | die of this invention. It is a figure which shows the result at the time of actually measuring and analyzing the variation | change_quantity of the angle after shrinkage | contraction with respect to the flow history about the evaluation metal mold | die of this invention. It is a perspective view which shows the injection molded product shape with a rib used in the Example of this invention. It is a perspective view which shows the shape before a deformation | transformation and the shape after a deformation | transformation when analyzing the injection molded product shape with a rib used in the Example of this invention with a shell element.

Explanation of symbols

1: Motor 2: Hopper 3: Cylinder 4: Mold 5: Cavity 6: Molded product material 7: Solidified molded product 301: T-shaped molded product (solid element)
302: T-shaped molded product base 303: T-shaped molded product rib 304: T-shaped molded product (shell element)
305: T-shaped molded product base portion 306: T-shaped molded product rib portion 307: Gate 308: Base portion branch portion element 309: Branch body branch portion element 310: With respect to the base portion Shape 311 that is a small protrusion 311: Shape after shrinking that is a protrusion that is small with respect to the base part 312: Shell element 313 that is a shape that is a small protrusion with respect to the base part 313 Shape 401 after shrinkage of shell element shaped like a small protrusion: Shape before shrinkage (L-shaped three-dimensional shape)
402: High-temperature surface of the mold 403: Shape after shrinkage (L-shaped three-dimensional shape)
404: Shape before shrinkage (L-shaped shape, shell element)
405: Shape after shrinkage (L-shaped shape, shell element)
406: Corner part 407: Thickness direction shrinkage 408: In-plane shrinkage (in-plane bending direction component)
409: A surface that equally divides an angle formed by two surfaces constituting the L-shaped shape 410: An angle of a corner portion divided by a surface that equally divides an angle formed by two surfaces constituting the L-shaped shape 413: In-plane direction Shrinkage (intersection line direction component of the corner part)
414: Element 415: Calculation point 501: Corner portion 502 of the L-shaped molded product before shrinkage 502: Corner portion 503 of the molded product after shrinkage: Base portion 504 before shrinkage: Base portion 601 after shrinkage T-shaped 602: Y-shaped 603: Umbrella-shaped 604: X-shaped 605: Star-shaped 700: Computer 701: Keyboard 702: Mouse 703: Display 704: Auxiliary storage device 901: T-shaped molded product 902: Sled Reference point 903: T-shaped molded product before shrinking 904: T-shaped molded product after shrinking 905: Shrinkage of flat plate portion (base portion) and rib (branched body) of T-shaped molded product Angle 906 formed in front: Angle formed after contraction of flat plate portion (base portion) and rib (branch body) of T-shaped molded product 907: Gate (filling direction perpendicular to rib)
908: Gate (filling direction is parallel to rib)
1201: Gate 1202: Warpage reference point 1203: Warpage reference point 1204: Warpage reference point 1205: Base portion 1206: Rib (branched body)
1207: Central portion of flat plate (depression amount measurement position)

Claims (16)

A warpage deformation analysis method for analyzing warpage deformation of a molded product by a programmed computer, wherein warpage deformation at a branch portion of the molded product is performed.
(1) The angle formed by the base portion and the branch body at the branch site, the average value in the thickness direction of the in-plane shrinkage rate at the branch site, and the thickness direction average of the thickness direction contraction rate at the branch site A branch structure warpage deformation amount calculating step for calculating a branch structure warpage deformation amount calculated based on the value and the branch structure parameter;
(2) In-plane direction and thickness direction distribution of in-plane direction shrinkage rates of the base portion and the branch body in the branch portion, and in-plane thickness direction shrinkage rates of the base portion and the branch body in the branch portion A bimetal warp deformation amount calculating step for calculating a bimetal warp deformation amount calculated based on the direction and thickness direction distribution;
(3) a branch part total warpage deformation amount calculating step of calculating a total warpage deformation amount based on the calculation results of the branch structure warpage deformation amount calculation step and the bimetal warpage deformation amount calculation step;
A warp deformation analysis method comprising: As the branch structure parameter, the distance from the branch site to the tip of the branch body, the flow history at the branch site, the ratio of the thickness of the base portion at the branch site and the thickness of the branch body at the branch site, 2. The warpage deformation analysis method according to claim 1, wherein at least one of ratios between a thickness of the base portion at the branching portion and a distance from the branching portion to a tip of the branching body is used. . The warpage deformation analysis method according to claim 2, wherein a ratio between a thickness of the base portion at the branch portion and a thickness of the branch body at the branch portion is used as the branch structure parameter. 4. The warp deformation analysis method according to claim 3, wherein when calculating the amount of deformation of the branched structure warp, the following expression or an expression mathematically equivalent thereto is used.

4. The warp deformation analysis method according to claim 3, wherein when calculating the amount of deformation of the branched structure warp, the following expression or an expression mathematically equivalent thereto is used.

As the branching structure parameter, the ratio between the thickness of the base portion at the branching portion and the thickness of the branch body at the branching portion, and the thickness of the base portion at the branching portion and the branching portion from the branching portion The warpage deformation analysis method according to claim 2, wherein a ratio to a distance to the tip of the body is used. 7. The warpage deformation analysis method according to claim 6, wherein, when calculating the amount of warpage deformation of the branched structure, the following equation or a mathematically equivalent equation is used.

7. The warpage deformation analysis method according to claim 6, wherein, when calculating the amount of warpage deformation of the branched structure, the following equation or a mathematically equivalent equation is used.

The ratio of the thickness of the base portion at the branch site to the thickness of the branch body at the branch site and the flow history at the branch site are used as the branch structure parameters. Warp deformation analysis method. 10. The warp deformation analysis method according to claim 9, wherein the following equation or an equation mathematically equivalent to the following equation is used in calculating the branch structure warpage deformation.

10. The warp deformation analysis method according to claim 9, wherein the following equation or an equation mathematically equivalent to the following equation is used in calculating the branch structure warpage deformation.

The warpage deformation analysis method according to claim 1, wherein the molded product is an injection molded product of a resin material. The warpage deformation analysis method according to claim 1, wherein the molded product is an injection molded product of a resin material containing a filler. The program for making a computer perform each process of the curvature deformation | transformation analysis method in any one of Claims 1-13. The computer-readable recording medium which recorded the program of Claim 14. An injection molding analyzer for analyzing the injection molding process of a molded product,
Warpage deformation at the branch part of the molded product,
(1) The angle formed by the base portion and the branch body at the branch site, the average value in the thickness direction of the inward front direction shrinkage rate at the branch site, the thickness direction shrinkage rate at the branch site, and the branch structure parameter And (2) warpage deformation at the branch portion of the molded product, and the in-plane direction of the in-plane shrinkage of the base portion and the branch body at the branch portion, and (2) Bi-metal warp deformation amount calculating means for calculating based on the thickness direction distribution and the in-plane direction and the thickness direction distribution of the shrinkage rate in the thickness direction of the base portion and the branched body at the branch portion;
(3) a branch portion total warpage deformation amount calculation means for calculating warpage deformation at the branch portion of the molded product based on an output of the branch structure warpage deformation amount calculation means and an output of the bimetal warpage deformation amount calculation means;
An injection molding analysis apparatus comprising:

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