JP2001071064A - Mold design apparatus, mold design method, and storage medium - Google Patents

Abstract

(57) [Problem] To efficiently perform setting work of an appropriate arrangement position and shape of an ejector pin. SOLUTION: In a design stage, a pressure acting on each ejector pin when a molded product is separated from a movable side mold is calculated,
Under the condition that the maximum pressure exceeds the yield pressure of the molding material, the shape and arrangement position of the set (input) ejector pins are evaluated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for evaluating an ejector pin for removing a molded product from a mold.

[0002]

2. Description of the Related Art Conventionally, a fixed-side mold and a movable-side mold which form the outer surface of a molded article are provided, and when the fixed-side mold and the movable-side mold are opened, the molded article attached to the movable-side mold is ejected. 2. Description of the Related Art There is known a mold provided with a protruding mechanism for protruding and separating by a pin.

As described above, when the ejector pins are protruded to separate the molded product from the movable side mold, and when the molded product is removed from the mold by moving the protruded amount (distance) while holding the molded product, A load corresponding to the release resistance generated when the molded product is separated from the movable mold is applied to the ejector pin.

[0004] The release resistance is determined by the surface roughness of the molded product, the draft angle of the surface, the thickness, the surface treatment condition of the mold, and the like. For this reason, the pressure applied to each ejector pin differs depending on the shape of the molded product, the state of the contact surface between the mold and the molded product, the shape of the ejector pin, and the position of the ejector pin. When the maximum pressure exceeds the yield stress of the molding material, plastic deformation occurs inside the molded product, which may cause molding failure.

Conventionally, the position and shape of the ejector pins are often determined only by the experience of the designer, and even when utilizing the results of flow analysis, the load applied to the ejector pins has not been considered.

[0006]

For this reason, conventionally, at the design stage, it was not possible to know whether or not plastic deformation would occur in a molded product.

Therefore, after the plastic deformation actually occurs in the molded product, the position and shape of the ejector pins are changed, and when the plastic deformation occurs even by this change, the position of the ejector pins is changed again. It is necessary to repeat such a work process many times, and it has not been possible to efficiently perform the work of setting the appropriate arrangement position and shape of the ejector pins.

The present invention has been made under such a background, and an object of the present invention is to make it possible to efficiently perform an operation of setting an appropriate arrangement position and shape of an ejector pin.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a fixed mold and a movable mold that form the outer surface of a molded product. In the mold designing apparatus for designing a mold having a projection mechanism for ejecting the molded product adhered to the movable side mold by an ejector pin at the time of opening and separating the molded article, evaluate the set arrangement position and shape of the ejector pin. Evaluation means.

The present invention also includes a fixed mold and a movable mold that form the outer surface of the molded article, and the molded article adhered to the movable mold when the fixed mold and the movable mold are opened. In a mold design apparatus for designing a mold having a projection mechanism for projecting and peeling off by an ejector pin, the set arrangement position and shape of the ejector pin, the three-dimensional shape of the molded product, and the molded product Using the mold release resistance generated when peeling from the movable mold, the pressure acting on the ejector pin when the molded article is peeled from the movable mold is calculated. Evaluating means is provided for evaluating the set arrangement position and shape of the ejector pin on condition that the yield stress is not more than the yield stress.

Further, the present invention has a fixed mold and a movable mold that form the outer surface of the molded article, and the molded article adhered to the movable mold when the fixed mold and the movable mold are opened. A mold design method for designing a mold having an ejecting mechanism for projecting and separating the ejector pins by an ejector pin includes an evaluation step of evaluating the set arrangement position and shape of the ejector pin.

Further, the present invention has a fixed mold and a movable mold that form the outer surface of the molded article, and the molded article adhered to the movable mold when the fixed mold and the movable mold are opened. In a mold design method for designing a mold having a protrusion mechanism for projecting and peeling off by an ejector pin, a set position and a shape of the ejector pin, a three-dimensional shape of the molded product, and Using the mold release resistance generated when peeling from the movable mold, the pressure acting on the ejector pin when the molded article is peeled from the movable mold is calculated. An evaluation step is provided for evaluating the set arrangement position and shape of the ejector pin on condition that the yield stress is not more than the yield stress.

Further, the present invention has a fixed mold and a movable mold that form the outer surface of the molded article, and the molded article adhered to the movable mold when the fixed mold and the movable mold are opened. Is a storage medium for storing a program executed by a mold designing apparatus for designing a mold having a protrusion mechanism for projecting and separating the ejector pins by an ejector pin, wherein the program includes a set arrangement position of the ejector pin and An evaluation routine for evaluating a shape is included.

Further, the present invention has a fixed mold and a movable mold that form the outer surface of the molded article, and the molded article adhered to the movable mold when the fixed mold and the movable mold are opened. Is a storage medium for storing a program executed by a mold designing apparatus for designing a mold having a protrusion mechanism for projecting and separating the ejector pins by an ejector pin, wherein the program includes a set arrangement position of the ejector pin and By using the shape, the three-dimensional shape of the molded article, and a release resistance generated when the molded article is separated from the movable side mold,
Calculate the pressure acting on the ejector pins when the molded product is separated from the movable mold, and set the ejector on the condition that a maximum pressure is not more than a yield stress of a molding material. An evaluation routine for evaluating the position and shape of the pin is provided.

In the present invention, the evaluation means / process /
The routine is based on whether or not the maximum pressure among the pressures acting on the ejector pins when the molded product is separated from the movable mold is equal to or less than the yield stress of the molding material. 2. The apparatus according to claim 1, wherein the position and the shape of the pin are evaluated.

Further, according to the present invention, the evaluation means / process /
The routine uses the set disposition position and shape of the ejector pin, the three-dimensional shape of the molded product, and the release resistance generated when the molded product is peeled from the movable mold, and the molded product The pressure acting on the ejector pin when separating from the movable mold is calculated.

Further, according to the present invention, the set position and shape of the ejector pin are determined by the evaluation means, step,
If the routine determines that the ejector pin is inappropriate, a guide means, a process, and a routine are provided for guiding the operator to reset the arrangement position and shape of the ejector pin.

Further, in the present invention, the mold designing apparatus includes:
The program is applied to a three-dimensional CAD device, and the program is executed by the three-dimensional CAD device.

[0019]

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

FIG. 1 is a functional block diagram of a three-dimensional CAD apparatus to which the present invention is applied. The three-dimensional CAD device is C
Various design processes are performed using the PU 13 as a core, and various processing programs to be executed by the CPU 13 are stored in the ROM 6. In addition, this processing program has a fixed mold and a movable mold that form the outer surface of the molded product, and when the fixed mold and the movable mold are opened,
It also includes a program for designing a mold having a protrusion mechanism for protruding and separating the molded product attached to the movable mold by an ejector pin. Also, the ejector pin pressure calculation unit 1 and the pressure condition determination unit 2 shown in FIG.
2 and a program corresponding to the flowchart of FIG. 2 are also included.

The CPU 13 has an input unit 3, a display unit 5, RAMs 7 to 10, a storage device 11, and a communication line 12 in addition to the ejector pin pressure calculation unit 1, the pressure condition determination unit 2, and the ROM 6. An output unit 4 for outputting data and the like to the outside is connected.

The storage device 11 stores a drawing database in which three-dimensional shape data of a plurality of molded products created by the three-dimensional CAD device are collected. The dimension data is RA
It is stored in M7. When the yield stress of the molding material is input by the input unit 3, the yield stress is determined by the RAM.
8 is stored. The release resistance generated when the molded product input by the input unit 3 is peeled from the movable mold is determined by the RAM 9.
The shape and arrangement position of the ejector pin are stored in RA
It is stored in M10.

The ejector pin pressure calculating section 1 has a RAM 7
The pressure applied to each ejector pin is calculated based on the molded article shape data stored in the RAM, the release resistance stored in the RAM 9, and the shape and position of the ejector pin stored in the RAM. The pressure condition determination unit 2 determines whether or not the maximum pressure among the calculated pressures of the ejector pins is equal to or lower than the yield stress of the molding material stored in the RAM 8.

Next, a process of evaluating the shape and arrangement position of the ejector pin, which is unique to the present invention, will be described with reference to the flowchart of FIG.

First, the three-dimensional shape data of a molded product created by the three-dimensional CAD device is read from the storage device 11 (step S1). Here, it is assumed that the three-dimensional shape data of FIG. 3 has been read. This three-dimensional shape is represented by XZ in FIG.
In a plane, the sectional shape is as shown in FIG. 4, and the sectional shape in FIG. 4 is a three-dimensional shape extruded in the Y direction. Next, the yield stress of the molding material is set and input (step 2). Here, it is assumed that the yield stress of the molding material is set and input as S.

Then, a release resistance generated when the molded product is peeled from the movable mold is set and inputted (step S3).
Here, it is assumed that the surfaces indicated by reference numerals F1 to F9 in FIGS. 4 and 5 are in contact with the movable side mold, and the release resistance is considered with respect to the surfaces F1 to F9. In addition, the direction in which the movable die is pulled out and the direction in which the ejector pins protrude are the same, and are directions indicated by reference sign E in FIGS. Here, the mold release resistance is determined by the surface roughness of the molded product, the draft angle of the surface, the wall thickness, the surface treatment condition of the mold, and the material of the molded product, and these values are predicted based on the results of experiments and analysis. Is what is done. Here, F
The release resistance per unit area with respect to the surface area of the surfaces 1 to F9 is predicted to be R1 to R9, respectively, and is assumed to be input. The surface areas of the surfaces F1 to F9 are A
1 to A9.

Next, the shape and position of the ejector pins are set and inputted (step S4). Here, as shown in FIG. 6, the ejector pins have P11 and P1 on the surface F1.
2 and P13, not on the planes F2, F4 and F6, but on the plane F3 at one point P31, on the plane F5 at two points P51 and P52, and on the plane F7 Has P71, P
72 and P73, and the plane F8 has P81, P8
2 and two points P91, P92 and P93 on the surface 9. In addition, it is assumed that all the ejector pins have the same cross-sectional shape and are circles with a radius r.

Next, the pressure applied to each ejector pin is calculated based on the molded article shape data, the release resistance, and the shape and position of the ejector pin (step S5). In addition,
When the molded product is separated from the movable mold, each surface F1 of the molded product
F9 includes release resistances R1 to R1 per unit area set as described above.
Since a load obtained by multiplying R9 by the surface area of each of the surfaces F1 to F9 acts, a distributed load is applied to the entire molded product. Therefore, the pressure applied to each ejector pin is
The load component in which each ejector pin supports the distributed load at its position is divided by the cross-sectional area of each ejector pin. Here, it is assumed that F11 to F93 are calculated as the pressure applied to each ejector pin as a result of the calculation.

Next, it is determined whether or not the maximum pressure among the calculated pressures applied to the ejector pins is equal to or less than the set yield stress S of the molding material (step S6). Here, it is assumed that the maximum value of the pressures of the ejector pins calculated in step S5 is the pressure F31 at the point P31 on the surface F3, and that F31> S.

As described above, when the maximum pressure among the pressures applied to the respective ejector pins is larger than the yield stress S of the molding material, the set shape and arrangement position of the ejector pins are inappropriate, and the molding product Since there is a possibility that plastic deformation may occur in the molded product when the mold is removed from the mold, a message for allowing the user to set the shape and the arrangement position of the ejector pins again is displayed on the display unit 5 (step S7). It returns to S4.

Here, in step S4, it is assumed that the shape and the arrangement position of the ejector pins are reset and the arrangement positions of the ejector pins shown in FIG. 7 are input (the cross-sectional shape of each ejector pin is FIG. 6). That is, in FIG. 7, in the previous ejector pin arrangement state, the pressure F31 at the point P31 on the surface F3 was larger than the yield stress S, so that the load applied to the surface F3 was shared and supported by the plurality of ejector pins. , P31 and P3 on the surface F3
The ejector pins were arranged at three points, 2 and P33, and the ejector pins on the other surfaces were arranged at exactly the same positions as in FIG.

Based on this arrangement, in step S5,
When the pressure applied to each ejector pin is calculated, the maximum pressure among them is the pressure F72 at the point P72, and the step S
6, it is assumed that the maximum pressure F72 is determined to be equal to or lower than the yield stress S. When the maximum pressure F72 is equal to or lower than the yield stress S, plastic deformation does not occur in the molded product when the molded product is removed from the mold, so that the shape of the ejector pin set in step S4 is not changed. Assuming that the arrangement position is appropriate, the process ends without prompting the user to reset the shape and the arrangement position of the ejector pin.

As described above, in the present embodiment, at the design stage, the pressure acting on each ejector pin when the molded product separates from the movable mold is calculated, and the maximum pressure among them is the yield pressure of the molding material. By evaluating the shape (position) of the ejector pin set (input) on the condition that the ejector pin exceeds the threshold value, the plastic deformation of the molded product is prevented from actually occurring.

Therefore, as in the conventional case, the shape and arrangement of the ejector pins are changed after the plastic deformation actually occurs in the molded product, and when the plastic deformation occurs even by this change, the shape of the ejector pins is again changed. It is not necessary to repeat the work process such as changing the arrangement and the arrangement many times, and it is possible to efficiently perform the work of setting the appropriate arrangement position and shape of the ejector pin.

[0035]

As described above, according to the present invention,
A protrusion that has a fixed mold and a movable mold that form the outer surface of the molded article, and that when the molds of the fixed mold and the movable mold are opened, the molded article attached to the movable mold is ejected by an ejector pin and peeled off. In a mold designing apparatus for designing a mold having a mechanism, evaluation means for evaluating the set position and shape of the ejector pin is provided, so that the work of setting an appropriate position and shape of the ejector pin can be efficiently performed. It is possible to do well.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a three-dimensional CAD apparatus to which the present invention is applied.

FIG. 2 is a flowchart showing a process of evaluating the shape and arrangement position of an ejector pin unique to the present invention.

FIG. 3 is a perspective view showing an example of a three-dimensional shape of a molded product.

FIG. 4 is a side view of the molded product, showing an operation surface of a mold release resistance.

FIG. 5 is a bottom view of the molded product, showing an action surface of a release resistance.

FIG. 6 is a diagram showing an example of the arrangement of ejector pins.

FIG. 7 is a diagram showing another example of the arrangement of the ejector pins.

[Explanation of symbols]

 1: Ejector pin pressure calculation unit 2: Pressure condition determination unit 3: Input unit 5: Display unit 6: ROM 7 to 10: RAM 11: Storage device (drawing database) 13: CPU

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B22C 9/06 G06F 15/60 612G 680C

Claims (18)

[Claims] 1. A mold having a fixed mold and a movable mold that form an outer surface of a molded article, wherein the molded article attached to the movable mold is ejected by an ejector pin when the fixed mold and the movable mold are opened. A mold designing apparatus for designing a mold having a projecting mechanism for projecting and separating, comprising an evaluation means for evaluating the set position and shape of the ejector pin. 2. The method according to claim 1, wherein the evaluating unit determines whether a maximum pressure among pressures acting on the ejector pins when the molded product is separated from the movable mold is equal to or less than a yield stress of a molding material. The apparatus according to claim 1, wherein the set position and shape of the ejector pin are evaluated. 3. The evaluation means according to claim 1, wherein the set position and shape of the ejector pin, a three-dimensional shape of the molded product, and a release resistance generated when the molded product is separated from the movable mold. 3. The mold design apparatus according to claim 2, wherein a pressure acting on the ejector pin is calculated when the molded product is separated from the movable mold. 4. A mold having a fixed mold and a movable mold that form the outer surface of the molded article, wherein the molded article attached to the movable mold is ejected by an ejector pin when the fixed mold and the movable mold are opened. In a mold designing apparatus for designing a mold having a protrusion mechanism for protruding and separating, a set position and shape of the ejector pin, a three-dimensional shape of the molded product, and the movable mold Using the release resistance generated when peeling from the, the pressure acting on the ejector pin when the molded product is peeled from the movable mold, the maximum pressure of which is less than or equal to the yield stress of the molding material. Or not,
A mold designing apparatus comprising: an evaluation unit for evaluating the set position and shape of the ejector pin. 5. A guide means for guiding the operator to reset the position and shape of the ejector pin when the set position and shape of the ejector pin are determined to be inappropriate by the evaluation means. The mold designing apparatus according to claim 1, further comprising: 6. The die designing apparatus according to claim 1, wherein said die designing apparatus is applied to a three-dimensional CAD apparatus. 7. A fixed-side mold and a movable-side mold that form an outer surface of the molded article, and when the fixed-side mold and the movable-side mold are opened, the molded article attached to the movable-side mold is ejected by an ejector pin. A mold design method for designing a mold having a protrusion mechanism for projecting and separating, comprising: an evaluation step of evaluating a set arrangement position and a shape of the ejector pin. 8. The evaluation step is performed under the condition that a maximum pressure among pressures acting on the ejector pins when the molded product is separated from the movable side mold is equal to or lower than a yield stress of a molding material. 8. The method according to claim 7, wherein the set position and shape of the ejector pin are evaluated. 9. The evaluation step includes determining a set arrangement position and a shape of the ejector pin, a three-dimensional shape of the molded product, and a release resistance generated when the molded product is separated from the movable mold. 9. The mold design method according to claim 8, wherein a pressure acting on the ejector pin is calculated when the molded product is separated from the movable mold. 10. A fixed-side mold and a movable-side mold that form an outer surface of a molded product, and when the fixed-side mold and the movable-side mold are opened,
In a mold design method for designing a mold having a projection mechanism for projecting and peeling the molded product adhered to the movable side mold by an ejector pin, the arrangement position and the shape of the ejector pin set and the molded product The pressure acting on the ejector pin when the molded product is separated from the movable mold is calculated using the three-dimensional shape of the molded product and the release resistance generated when the molded product is separated from the movable mold. , Provided that the maximum pressure is not more than the yield stress of the molding material,
A die design method comprising an evaluation step of evaluating the set arrangement position and shape of the ejector pin. 11. A guiding step of guiding the operator to reset the arrangement position and shape of the ejector pin when the set arrangement position and shape of the ejector pin are evaluated as inappropriate by the evaluation step. The mold designing method according to claim 7, further comprising: 12. The mold design method according to claim 7, wherein said mold design method is applied to a three-dimensional CAD apparatus. 13. A fixed-side mold and a movable-side mold that form an outer surface of a molded product, wherein when the fixed-side mold and the movable-side mold are opened,
A storage medium for storing a program executed by a mold designing apparatus for designing a mold having a protrusion mechanism for protruding and separating the molded product attached to the movable side mold by an ejector pin, wherein the program includes: A storage medium including an evaluation routine for evaluating the set arrangement position and shape of the ejector pin. 14. The evaluation routine is performed under the condition that a maximum pressure among pressures applied to the ejector pins when the molded product is separated from the movable side mold is not more than a yield stress of a molding material. 14. The storage medium according to claim 13, wherein an arrangement position and a shape of the input ejector pin are evaluated. 15. The evaluation routine may include determining a set position and a shape of the ejector pin, a three-dimensional shape of the molded product, and a release resistance generated when the molded product is separated from the movable mold. 15. The storage medium according to claim 14, wherein a pressure acting on the ejector pin is calculated when the molded product is separated from the movable mold. 16. A fixed-side mold and a movable-side mold that form the outer surface of a molded product, and when the fixed-side mold and the movable-side mold are opened,
A storage medium for storing a program executed by a mold designing apparatus for designing a mold having a protrusion mechanism for protruding and separating the molded product attached to the movable side mold by an ejector pin, wherein the program includes: Using the set position and shape of the ejector pin, the three-dimensional shape of the molded product, and the release resistance generated when the molded product is peeled from the movable mold, the molded product is moved to the movable side. Calculate the pressure acting on the ejector pin when peeling from the mold, provided that the maximum pressure among them is not more than the yield stress of the molding material,
A storage medium including an evaluation routine for evaluating the set arrangement position and shape of the ejector pin. 17. A guide routine that guides the operator to reset the position and shape of the ejector pin when the set position and shape of the ejector pin are determined to be inappropriate by the evaluation routine. 17. The storage medium according to claim 13, wherein the storage medium is included. 18. The storage medium according to claim 13, wherein said program is executed by a three-dimensional CAD device.