JP2003266471A - Molding method and molding die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding method for molding an injection press-molded product and an injection-molded product simultaneously, and a molding die. <P>SOLUTION: Cavities 56a and 56d are arranged so that a resultant force of a press pressure and a resultant force of an injection pressure, both acting upon a movable half 10b of a mold, is balanced against a pressurizing force imparted by a pressurizing means(a hydraulic cylinder and the like) from a positional viewpoint. Further, during molding, a resin for injection press-molding is injected into an injection press cavity 55 (56a and 56b) and is pressed to obtain an injection press-molded product. In addition, after completing a pressing operation, a resin for injection molding is injected into an injection cavity 57 (56c and 56d) to obtain an injection-molded product. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding method and a molding die, and more particularly to a molding method for a plastic product using both an injection press molding method and an injection molding method, and a molding die used in the molding method.

[0002]

2. Description of the Related Art As a method for molding a plastic product,
Injection press molding and injection molding are widely known.

In the injection press molding method, a molten resin is injected into a cavity with a mold slightly opened, and the molten resin is pressed by a pressurizing operation of a mold closing device, and the molten resin is cooled to form a molded product. Is a way to get. The injection press molding apparatus used in this method is configured to perform a pressing operation together with an injection operation, and the injection press molding die is
Generally, it is composed of a male type and a female type.

On the other hand, the injection molding method is a method in which a molten resin is injected into a cavity with a mold closed and the molten resin is cooled to obtain a molded product. The injection molding apparatus used in this method is configured to perform the injection operation after the mold closing operation, and the injection molding die is configured to define the cavity filled with the molten resin.

Since both the injection press molding method and the injection molding method have a step of closing a mold and a step of injecting a molten resin, a single device can be used for both methods by changing a control program. Is possible. However, there has been no idea of simultaneously performing injection press molding and injection molding using a single molding die to simultaneously mold an injection press molded article and an injection molded article.

[0006]

Conventionally, there was no idea of simultaneously molding an injection press molded product and an injection molded product. Therefore, in order to mold an injection press molded product and an injection molded product at the same time, A mold and a molding machine must be prepared for each of these molding methods, which causes a problem of high equipment cost.

Therefore, a main object of the present invention relates to a molding method and a molding die which can reduce equipment costs by simultaneously molding an injection press molded product and an injection molded product.

[0008]

According to a first aspect of the present invention, an "injection press cavity (55) used in injection press molding, an injection cavity (57) used in injection molding, and an injection press are performed. A molding method (10) having at least two or more types of common cavities (58) used for common molding in which resin is injected and filled. ) Molds for molding (10)
The movable mold (10b) that constitutes the above is displaced in the closing direction, the injection press molding resin is injected into the injection press cavity (55) before the molding mold (10) is completely closed, and the injection press molding is performed. Injection molding process, in which the molding die (10) is completely closed while pressing the resin for molding, (b) the movable die (10b) constituting the molding die (10) is displaced in the closing direction, and molding is performed. Mold (1
(0) after completely closing the injection molding resin injection cavity
Injecting and filling the inside of (57), (c) displacing the movable mold (10b) constituting the molding mold (10) in the closing direction,
Shared cavity (58) before the mold (10) is completely closed
Injecting injection press molding resin into the mold, completely closing the molding die (10) while pressing the injection press molding resin, and after the molding die (10) is completely closed, the common cavity ( 58), the injection molding resin is further injected and filled, the common molding step, (d) When molding at least two kinds of molding steps from (a) to (c) above, molding is first performed. After performing pressing, injection is performed, (e) the injection press molding resin and the injection molding resin are cooled, and (f) the molded product is released from the mold. "

In this invention, the injection press molding resin is injected into the injection press cavity (55) and then the injection press molding resin is pressed to obtain an injection press molding product. After the completion of pressing, injection molding resin is injected into the injection cavity (57) to obtain an injection molded product. In addition, in the common cavity (58), the injection press molding resin is injected into the common cavity (58),
Mold for molding while pressing the injection press molding resin
After completely closing (10) and the molding die (10) completely closed,
Further, a common molded article is obtained by injection-filling the common cavity (58) with an injection molding resin.

The invention described in claim 2 is a "fixed mold (1
0a) and the movable mold (10b), the injection press cavity (5
5) and injection cavity (57), movable mold (10b)
A molding die (10) for holding the injection press pressure at the time of injection press molding and the injection pressure at the time of injection molding by the pressurizing means connected to, of the press pressure acting on the movable mold (10b). The resultant force is positionally balanced with the pressure applied by the pressurizing means,
In addition, a molding die in which the injection press cavity (55) and the injection cavity (57) are arranged so that the resultant force of the injection pressure acting on the movable mold (10b) is positionally balanced with the pressure applied by the pressurizing means. Type (10) ".

In the present invention, both the resultant force of the press pressure and the resultant force of the injection pressure acting on the movable mold (10b) are positionally balanced with the pressing force by the pressing means. That is, the combined force of the pressure acting on the molding die (10) from the resin in the cavity during the injection press molding and the injection pressure, and the pressing force acting on the molding die (10) from the pressing means. Balance at one point.

According to a third aspect of the invention, in the molding die (10) according to the second aspect, "at least one of the injection press cavity (55) and the injection cavity (57) is plural". It is a feature.

According to the present invention, the injection press cavity (55)
There may be multiple injection cavities (57),
Multiple injection press cavities (55)
7) may be one.

According to a fourth aspect of the invention, in the molding die (10) according to the third aspect, "a common cavity (58) in which the injection press cavity (55) and the injection cavity (57) are integrated. ) Is provided ".

In the present invention, the injection press cavities (55) (56a) and the injection cavities (57) (56c) which form the common cavity (58) are functionally independent, and therefore physically independent. There is no substantial difference with the injection press cavities (55) (56b) and the injection cavities (57) (56c) of.

[0016]

According to the invention described in claim 1, an injection press molded product molded in the injection press cavity, an injection molded product molded in the injection cavity, and a common cavity including the injection press cavity and the injection cavity. It is possible to simultaneously obtain at least two types of molded products among the common molded products molded in (1). Therefore, the equipment cost can be significantly reduced as compared to the case where at least two types of injection-press molded products, injection-molded products, and shared molded products are molded using different molding devices and molding dies. .

According to the invention described in claims 2 to 4, in the injection press molding and the injection molding, respectively,
The resultant force of the pressure acting on the movable mold forming the molding mold from the resin in the cavity and the pressurizing means (hydraulic cylinder, etc.)
Positionally balances with the pressing force acting on the movable mold (when there are a plurality of pressing forces, the resultant force). Therefore, in both the injection press cavity and the injection cavity, the press pressure and the injection pressure can be held uniformly, and the occurrence of molding defects such as burrs can be prevented.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A molding die (10) of one embodiment of the present invention shown in FIGS. 1 and 2 is shown in FIG. 3 for simultaneously molding an injection press molded product and an injection molded product. It is used by being attached to such an injection molding machine (12). Here, "injection press molded product" means an injection press cavity.
(55) refers to a molded product that is injection press molded, "injection molded product" refers to a molded product that is injection molded into the injection cavity (57), and "common molded product" refers to a common cavity ( 58)
(Injection press cavity (55) and injection cavity (57) are integrally formed) common molding (injection press in the common cavity, and then injection filling with resin) The molded product is defined as

The molding die (10) has a fixed die (10a) and a movable die (10b) which cooperate with each other to form a plurality of cavities (56a) to (56d). The arrangement of 56a) to (56d) is characteristic of this embodiment.

The arrangement of the cavities (56a) to (56d) is as follows.
Since it is determined in relation to the pressing force F0 received by the movable mold (10b) from the injection molding machine (12), the outline of the injection molding machine (12) will be first described below, and then the molding metal mold will be described. The mold (10) will be described in detail.

As shown in FIG. 3, the injection molding machine (12) has a fixed plate (14) and a base (16), and an upper part of the fixed plate (14) is
The mold clamping device (20) is connected through a plurality of (four in this embodiment) tie bars (18). Further, the fixed die (10a) of the molding die (10) is attached to the upper part of the fixed platen (14), and the movable die plate (24) is slidably attached to the tie bar (18). A hydraulic cylinder (22) as a pressurizing means is attached to the tightening device (20). Then, the movable die plate (2
On the surface facing the fixed mold (10a) of 4), the molding mold (10)
The movable mold (10b) is attached, and the piston (26) constituting the hydraulic cylinder (22) is connected to the surface facing the mold clamping device (20).

An injection machine (28) is mounted on the base (16).
The injection machine (28) includes a heating cylinder (30),
The screw (32) is housed inside the (30), and the hopper (34) is attached to the upper part of the heating cylinder (30). And the nozzle (36) formed at the tip of the heating cylinder (30)
Is connected to a sprue bush (38) formed on a side portion of the fixed mold (10a).

The type of injection molding machine is not limited to this embodiment, and an injection molding machine of a type in which a movable mold moves laterally may be used.

As described above, the molding die (10) includes the fixed die (10a) attached to the fixed platen (14) and the movable die (10b) attached to the movable die plate (24). including.

As shown in FIGS. 1 and 2, the fixed mold (10a) includes a plate-shaped mold body (40), and a surface of the mold body (40) facing the movable mold (10b). The cavity (56a) to the mold (44) (see FIG. 2) formed on the movable mold (10b).
(56d) a plurality of molds (female mold in this embodiment) (46)
And a guide pin hole (42) (see FIG. 1) engaged with a guide pin (54) formed in the movable mold (10b).
A sprue bush (38) (see FIG. 3) is formed on a side surface of the mold body (40) (a surface facing the injection machine (28)), and the sprue bush is provided inside the mold body (40). A plurality of runners (48) communicating with the bush (38) and each mold (46) is formed. Further, each runner (48) is provided with a valve gate (50) for adjusting the injection start timing and the injection amount of the molten resin.

As shown in FIGS. 1 and 2, the movable mold (10b) includes a plate-shaped mold body (52), and a surface of the mold body (52) facing the fixed mold (10a). In addition, a plurality of molds (male molds in this embodiment) (44) (FIG. 2) that cooperate with the mold (46) formed in the fixed mold (10a) to form the cavities (56a) to (56d). And a guide pin (54) engaged with the guide pin hole (42) formed in the fixed mold (10a).

In the molding die (10), as described above, the cavities (56a) to (56d) are formed by the die (46) of the fixed die (10a) and the die (44) of the movable die (10b). ) Is formed, in the molding die (10) of this embodiment, the cavities (56a) and (56
b) is the injection press cavity (55), and the cavity (56
c) and (56d) are injection cavities (57).

In these cavities (56a)-(56d), as shown in FIG. 2, the pressure P (injection pressure or press pressure) of the molten resin is applied to the inner surface of the mold (44) of the movable mold (10b). To work. Therefore, if the resultant force F1 of the pressure P acting on the entire movable mold (10b) is not positionally balanced with the pressing force F0 by the piston (26) of the hydraulic cylinder (22), the movable mold (10b). A shearing force acts on the movable mold (10b) by the pressing force F0 that tries to close and the resultant force F1 that tries to open, and the pressure of the molten resin is uniformly held in each cavity (56a) to (56d). Can not.

Therefore, in this embodiment, the injection press cavity (55) ((56a) and (56b)) and the injection cavity (57).
((56c) and (56d)) is the movable mold (10b) is the piston
It is arranged as follows in relation to the pressing force F0 received from (26).

That is, as shown in FIG. 4, the movable mold (1
The point where 0b) receives the pressing force F0 from the piston (26) is G0, and an xy coordinate system is assumed with this point G0 as the origin. Then, in this coordinate system, the injection press cavities (55) ((56a) and (56b)) are arranged in accordance with the formula 1, and the injection cavities (57) ((56c) and (56d)) are defined by the formula 2. Arrange according to the formula.

However, the "resulting force acting point" in the equations 1 and 2 means the point where the resultant force f (pressure P × area S: the same applies hereinafter) acts in each of the cavities (56a) to (56d). In this embodiment, the center of gravity of a figure obtained by orthographically projecting the cavities (56a) to (56d) onto the coordinate system (hereinafter referred to as "orthographic projection figure") is matched.

[Formula 1] Xa × P × Sa = Xb × P × Sb Ya × P × Sa = Yb × P × Sb Xa: Distance xb from the origin G0 to the resultant force acting point Ga of the cavity (56a) Xb : Distance from the origin G0 to the resultant force acting point Gb of the cavity (56b) in the x-axis direction Ya: Distance from the origin G0 to the resultant force acting point Ga of the cavity (56a) Yb: Yb: The resultant force from the origin G0 to the cavity (56b) Distance to the action point Gb in the y-axis direction Sa: area of the orthographic projection figure corresponding to the cavity (56a) Sb: area of the orthographic projection figure corresponding to the cavity (56b) P: pressure acting on the inner surface of the mold (46) ( Pressing pressure) [Equation 2] Xc x P x Sc = Xd x P x Sd Yc x P x Sc = Yd x P x Sd Xc: Distance xd in the x-axis direction from the origin G0 to the resultant action point Gc of the cavity (56c). : Distance in the x-axis direction from the origin G0 to the resultant force application point Gd of the cavity (56d) Yc: From the origin G0 to the resultant force application point Gc of the cavity (56c) Y-axis direction distance Yd: Y-axis direction distance from the origin G0 to the resultant force application point Gd of the cavity (56d) Sc: Orthographic projection area corresponding to the cavity (56c) Sd: Orthographic projection figure corresponding to the cavity (56d) Area P: Pressure acting on the inner surface of the mold (46) (injection pressure) Each cavity (56a) to (56d) according to the equations (1) and (2)
, The pressure P acting on the entire movable mold (10b)
The resultant force F1 of (1) is positionally balanced with the pressing force F0 by the hydraulic cylinder (22) (piston (28)). That is, in each of the cavities (56a) to (56d), the moment (centered around the origin G0) considered by the resultant force f is balanced, and the line of action of the pressing force F0 and the line of action of the resultant force F1 coincide.

Therefore, the origin G0 is attached to the movable mold (10b).
The force to rotate this around does not act,
The injection pressure and the press pressure can be uniformly held in each of the cavities (56a) to (56d).

In this embodiment, the surface on which the pressure P for opening the movable mold (10b) acts (hereinafter referred to as "pressurizing surface") is orthogonal to the mold opening direction. In the cavities (56a) to (56d), the center of gravity of the orthographic projection and the point of resultant force coincide. However, when the pressure surface is inclined with respect to the mold opening direction, the center of gravity of the orthographic projection and the resultant point of action of force may not match, and therefore the determination of the point of action of force requires caution.

A method for simultaneously molding a plurality of injection press-molded products and a plurality of injection-molded products using the molding die (10) will be described below with reference to the timing chart of FIG.

When the molding die (10) is mounted on the injection molding machine (12) and the drive switch of the injection molding machine (12) is turned on, first,
The mold closing operation of the molding die (10) starts, and the movable die (10b)
Is displaced in the closing direction. Then, the injection press molding process is started at a predetermined timing before the molding die (10) is completely closed. That is, the required amount of molten resin is injected into the injection press cavity (55) ((56a) and (56b)),
The movable mold (10b) is further displaced in the closing direction and the molten resin is pressed. Valve gate in injection press molding process
The injection cavity (57) ((5
Injection of molten resin into 6c) and (56d) is prohibited, and the injection pressure into the injection press cavity (55) ((56a) and (56b)) is set to a low pressure.

When the molding die (10) is completely closed, the next injection molding process is started. That is, the injection of the molten resin into the injection press cavity (55) ((56a) and (56b)) is prohibited by operating the valve gate (50), and the injection cavity (57) ((56c) and (56d )) Is injected into the molten resin. In this step, the injection pressure of the molten resin is set higher than in the injection press molding step. After the molten resin is filled in the injection cavities (57) ((56c) and (56d)), the injection is continued for a predetermined time to maintain the pressure.

In the next cooling step, the molten resin is cooled and cured with the molding die (10) kept closed. When the molten resin is completely cured, the mold opening operation of the molding die (10) is started and the movable die (10b) is displaced in the opening direction. Then, the molded product is released from the mold.

According to this embodiment, one molding die (1
Since (0) can be used to continuously perform injection press molding and injection molding, it is not necessary to prepare a plurality of molding dies for molding the injection press molded product and the injection molded product.
Therefore, the equipment cost can be significantly reduced.

Further, in the injection press molding and the injection molding, respectively, the resultant force F1 of the pressure P acting on the entire movable mold (10b) from the molten resin in the cavities (56a) to (56d) and the pressurization From the piston (28) as a means to the movable mold (10
Since the pressing force F0 acting on b) can be positionally balanced, the pressing pressure and the injection pressure can be uniformly held in any of the cavities (56a) to (56d). Therefore, it is possible to prevent the occurrence of molding defects such as burrs.

In the injection press molding process, the piston
(28) pressurizes the molten resin with a predetermined pressure, and in the injection molding process, holds the injection pressure of the molten resin with a predetermined holding force by the piston (28) so that a molded product is obtained at each stage. Therefore, the capacity of the piston (28) can be effectively utilized in two processes that are temporally mixed. Therefore, a hydraulic cylinder (22) (piston (2
Compared with the case where only one of injection press molding or injection molding is performed using 8)), the total projected area of the molded product that can be molded in one step can be significantly increased.

In the above embodiment, each cavity (5
Although the resultant force acting points Ga to Gd of 6a) to (56d) are displaced from each other in both the x-axis direction and the y-axis direction,
For example, as shown in FIG. 6, the resultant force action points Ga to Gd are represented by x.
It may be arranged on the axis (or on the y axis).

Further, in the above embodiment, the pressing force F0 is applied to the center of the movable mold (10b) by one hydraulic cylinder (22). However, for example, by a plurality of hydraulic cylinders (22). A pressure may be applied to the peripheral edge of the movable mold (10b). In this case, each hydraulic cylinder
(22) The point at which the resultant force F0 of the pressure applied by the piston (26) acts is G0.

As the pressurizing means, a hydraulic cylinder (2
Instead of 2), a toggle mechanism driven by a motor, an air cylinder, or the like may be used.

Further, for example, as shown in FIG. 6, the injection press cavities (55) (56a) and the injection cavities (57) (56c) may be integrally formed as a common cavity (58). Also in this shared cavity (58), since the injection press cavities (55) (56a) and the injection cavities (57) (56c) are functionally independent, the above equations (1) and (2) are applied to these. It can be applied as it is.

In each of the above embodiments, the number of injection press cavities (55) and injection cavities (57) (including those forming the shared cavity (58)) is plural, but the injection press There may be one of the cavity (55) or the injection cavity (57). For example, as shown in FIG. 7, there may be one injection press cavity (55) (60a) and two injection press cavities (57) ((60b) (60c)), or as shown in FIG. So that the injection press cavity (5
5) ((62a) (62b)) is two, injection cavity (57) (62c)
There may be only one.

Also, for example, in the embodiment of FIG. 7, the injection press cavity (55) (60a) and the two injection cavities
One of (57) ((60b) and (60c)) may be integrally formed as a common cavity (not shown), or two injection press cavities (55) (( 62
One of (a) and (62b)) may be integrally formed as a common cavity (not shown).

As described above, it goes without saying that even if one of the injection press cavity (55) and the injection cavity (57) is one, the above equations (1) and (2) can be applied as they are.

Further, in the injection press molding process,
Instead of pressing the molten resin while injecting it into the injection press cavity (55), a method of pressing after the molten resin has been injected may be adopted.

The type of resin used in the present invention is not particularly limited. [Verification of Practicality by Prototype] The inventors of the present invention prototyped the molding die (10) of the embodiment of FIG. 6 according to the following conditions (a) to (d), and obtained a molded product of a target shape. I was able to confirm.

(A) Injection press cavity (55) (56b): area of orthographic projection Sb = 4100 cm ² resultant force acting point Gb (x, y) = (− 61,0) (b) injection cavity (57) ( 56d): Area of orthographic projection figure Sd = 1100cm ² Resulting point of action Gd (x, y) = (− 843,0) (c) Injection press cavity (56a) included in common cavity (58): Orthographic projection figure Area Sa = 1300 cm ² Resultant point of action Ga (x, y) = (193,0) (d) Injection cavity (5) included in common cavity (58)
6c): area of orthographic projection Sc = 1100 cm ² resultant force acting point Gc (x, y) = (843,0) (e) injection molding machine: mold clamping force 670 ton (f) material: MI (melt flow index) = 20 g / 10 mi
n

[Brief description of drawings]

FIG. 1 is a perspective view showing a molding die according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a molding die of FIG. 1 embodiment.

FIG. 3 is a diagram showing an injection molding machine to which the molding die of FIG. 1 embodiment is applied.

FIG. 4 is a diagram showing an arrangement state of each cavity in the embodiment of FIG.

FIG. 5 is a timing chart showing a molding method according to an embodiment of the present invention.

FIG. 6 is a diagram showing another arrangement state of each cavity.

FIG. 7 is a view showing still another arrangement state of each cavity.

FIG. 8 is a diagram showing still another arrangement state of each cavity.

[Explanation of symbols]

(10)… Molding mold (10a)… Fixed mold (10b)… Movable mold (12)… Injection molding machine (14)… Fixed plate (16) ... Base (18) ... Tie bar (20)… Clamping device (22) ... Hydraulic cylinder (24)… Movable die plate (26) ... Piston (28) ... Injection machine (38) ... Sprue Bush (48)… Runner (50)… Valve gate (44), (46) ... type (56a), (56b) ... Injection press cavity (56c), (56d) ... Injection cavity

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F202 CA11 CB01 CK07 CL02                 4F206 JA03 JA07 JN12 JN15 JN25                       JN33 JQ81 JQ90

Claims (4)

[Claims] 1. At least two of an injection press cavity used for injection press molding, an injection cavity used for injection molding, and a common cavity used for common molding in which a resin is further injected and filled after injection pressing. A molding method for molding using a molding die having more than one type of cavity, comprising: (a) displacing a movable mold forming the molding die in a closing direction to complete the molding die. Injection-molding resin is injected into the injection-press cavity before closing, and the molding die is completely closed while pressing the injection-molding resin, (b) the molding die An injection molding step, in which a movable mold forming the mold is displaced in a closing direction, and injection molding resin is injected and filled into the injection cavity after the molding mold is completely closed, before (c) The movable mold forming the molding die is displaced in the closing direction, the injection press molding resin is injected into the common cavity before the molding die is completely closed, and the injection press molding resin is pressed. While the mold for molding is completely closed, and after the mold for molding is completely closed, injection molding resin is further injected and filled into the common cavity, (d) (a) to (a) When at least two types of molding processes are selected from the process c) and molding is performed, first, injection press molding is performed and then injection molding is performed. (e) The injection press molding resin and the injection molding resin And (f) releasing the molded product from the mold. 2. An injection press cavity and an injection cavity are constituted by a fixed mold and a movable mold, and a press pressure at the time of injection press molding and an injection pressure at the time of injection molding by a pressurizing means connected to the movable mold. A mold for holding, wherein the resultant force of the press pressure acting on the movable mold is positionally balanced with the pressure applied by the pressing means, and the injection acts on the movable mold. A molding die in which the injection press cavity and the injection cavity are arranged so that the resultant force of the pressures balances in position with the pressure applied by the pressing means. 3. The molding die according to claim 2, wherein at least one of the injection press cavity and the injection cavity is plural. 4. The molding die according to claim 3, further comprising a common cavity in which the injection press cavity and the injection cavity are integrated.