JP2007230031A - Injection mold and injection molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection mold which is improved in the smoothness and gloss of an outer surface or a side end part of a molded product even if a coating material is injected in a stage that the product is cured after injection molding and is free from the leakage of coating to the outside of a mold, and an injection molding method using the mold. <P>SOLUTION: The injection mold 1 is composed of a movable mold 1a and a fixed mold 1b and constituted so that a synthetic resin is injected in the mold and the coating material is injected in the mold after the molding of the synthetic resin to coat the surface of an injection-molded product by in-mold coating. The injection mold 1 is equipped with the core 2 arranged in one of the movable mold 1a and the fixed mold 1b to form a cavity 9 and a core moving means for horizontally moving the core 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an injection mold for coating an injection molded product in a mold and an injection molding method thereof.

When resin is used for the outer panels of automobiles, etc., coating is performed with the aim of improving appearance, improving weather resistance, chemical resistance, and scratch resistance. When performing this painting, a wide painting booth is required. In addition, the exterior coating of resin products is a factor that increases the cost of products.
Therefore, recently, a technique for painting in a mold has been proposed in order to reduce the cost without requiring a painting booth.

  FIG. 9 is a front view showing a conventional injection molding machine. As shown in FIG. 9, the injection molding machine 100 has a mold clamping device 110 disposed on the left side and an injection device 120 disposed on the right side. A mold clamping cylinder 105 is disposed at the left end of the mold clamping device 110 and moves the movable mold 104. An injection cylinder 125 is disposed at the right end of the injection device 120 and injects a plasticized synthetic resin molding material into the cavity.

  FIG. 10 shows a mold for applying a coating material to an injection-molded product in the mold, and is an enlarged sectional view of a part a shown in FIG. As shown in FIG. 10, in the mold clamping device 110 of the injection molding machine 100, the movable platen 102 is moved in the advance / retreat direction by the mold clamping cylinder 105. A cavity 106 is formed in the fixed mold 103 and the movable mold 104, and a synthetic resin molding material (hereinafter referred to as a synthetic resin) is injected from the injection cylinder 107 into the cavity 106 through the nozzle 108 and the sprue 109.

When the synthetic resin is properly cured in the mold, the mold clamping pressure is reduced, and the fixed mold 103 and the movable mold 104 are opened to such an extent that the fitting portion is not separated. Next, the injector 112 operates its shut-off pin 112A to open the injection port of the injector 112. Next, the plunger regulator 113A for injecting the coating material of the measuring cylinder 113 is operated to inject and fill the coating material, which is the coating material, between the cavity 106, that is, the inner wall of the fixed mold 103 and the injection molded product. .
After injecting the coating material, the shut-off pin 112A is popped out to close the injection port, the mold clamping cylinder 105 is operated, the mold clamping operation is performed again, the coating material is diffused in the mold, and the surface of the injection molded product is spread. Coating is performed, the coating material is cured, and an injection molded product is taken out from the mold to obtain a product.

JP-A-11-277777 (paragraph numbers 0011 to 0016, FIGS. 1 and 2)

  However, in the conventional method, there is a problem that if the injection molding is performed after the mold is clamped and the coating material is injected when the product is cured, the outer surface of the molded product, the smooth surface and the glossy surface of the side edge are poor. there were. In addition, since the mold is slightly opened after the product is cured and the paint is injected, there is a problem that the paint leaks out of the mold.

  Therefore, the present invention has a good smooth surface and glossy surface on the outer surface and side edges of the molded product even when the coating material is injected after the product is cured after the injection molding, and the paint is out of the mold. It is an object to provide an injection mold that does not leak and an injection molding method thereof.

  The invention according to claim 1 is composed of a movable mold (1a) and a fixed mold (1b), injecting a synthetic resin by applying clamping pressure in the mold, and after molding into the mold In an injection mold (1) in which a coating material is injected to cover the surface of an injection molded product in the mold, the cavity (9) is disposed on one of the movable mold (1a) and the fixed mold (1b). And a core moving means for horizontally moving the core (2).

  The invention according to claim 2 is the injection mold (1) according to claim 1, wherein the core moving means is the movable mold (1a) or the fixed mold (1b). A plurality of cylinders (30, 31) in which a plurality of piston rods (30b, 31b) having different lengths are provided in one of the cylinders (3) arranged in either one of the cylinders (3) are provided.

  The invention according to claim 3 is the injection mold (1) according to claim 1 or 2, wherein the fixed mold (1b) covers the outer surface of the injection molded product (22). The first injector (6) is provided, and the movable mold (1a) is provided with a second injector (7) for covering the back surface of the injection molded product (22).

The invention according to claim 4 is composed of a movable mold (1a) and a fixed mold (1b), injecting a synthetic resin by applying clamping pressure in the mold, and after molding into the mold In an injection mold (1) for injecting a coating material and coating the surface of an injection molded product in the mold,
A core (2) that is disposed on one of the movable mold (1a) and the fixed mold (1b) to form a cavity (9), and a core moving means that moves the core (2) horizontally. An injection molding method (1) including: a step of advancing the movable mold (1a); and the movable mold (1a) is a fixed mold (1b). ), The cavity (9) is formed, the synthetic resin melted by heating is injected into the cavity (9) at a high pressure, and the injection molded product (22) is molded, and the core The moving means is operated to advance the piston (3a), press the thickness of the coating film of the injection molded product (22), homogenize the density of the molded product, and then retract the core (2). A step of forming a gap, and the fixed mold (1b) and the injection molded product (22) A step of injecting a coating material into the gap provided in the step, and a step of retracting the movable mold (1a) after the injection molded product (22 ′) is cured to obtain a finished injection molded product (22 ″), It is characterized by including.

  The invention according to claim 5 is the injection molding method according to claim 4, wherein the core moving means is re-actuated to press the core (2), and the coating material for the injection molded product (22) is provided. The method further includes a re-pressing step of pressing, and an injection step of providing a gap in the back surface portion of the injection molded product (22 ′) by the re-pressing step and injecting a coating material into the gap of the back surface portion. .

  The invention according to claim 6 is the injection molding method for an automobile body outer plate member according to claim 4 or claim 5, wherein the injection-molded product (22) is a synthetic resin, Is a thermosetting resin.

  The invention according to claim 7 is the injection mold (11) according to claim 1, wherein the first injection mold (11a) is the first movable mold (1a) or the first mold. A first core (2a) disposed in one fixed mold (1b), a first cavity (9a) formed by the first core (2a), and the first core (2a) horizontally And a second injection mold (11b) is connected to the second movable mold (1c) or the second fixed mold (1d). Similarly, a second core (2b) is incorporated to form a second cavity (9b), and second core moving means for moving the second core (2b) horizontally is provided. The injection mold (11a) and the second injection mold (11b) are characterized in that they are arranged vertically or in parallel.

The invention according to claim 8 is the claim 7 injection mold according (11), said first injection mold (11a) is a synthetic resin molding mold, the second injection mold (11b) is a coating mold.

  The invention according to claim 9 is the injection mold (11) according to claim 8, wherein the second cavity (9b) of the second injection mold (11b) is more than the first cavity (9a). In order to ensure the clearance gap of a coating | covering material, it is produced 20-200 micrometers large, It is characterized by the above-mentioned.

In the invention according to claim 10, the first injection mold (11a) is the first movable mold (1a) or the first core (2a) disposed in the first fixed mold (1b). And a first cavity (9a) formed by the first core (2a) and first core moving means for moving the first core (2a) horizontally, and a second injection In the molding die (11b), the second movable die (1c) or the second fixed die (1d) contains the second core (2b) in the same manner as described above, and the second cavity (9b) ) And a second core moving means for moving the second core (2b) horizontally, the first injection mold (11a) and the second injection mold (11b) An injection molding method in which injection molding is performed by an injection mold (11) arranged in a vertical arrangement, or in a horizontal arrangement on the left and right, The moving mold (1a) advances, the first movable mold (1a) is pressed against the first fixed mold (1b) and closed, and the first cavity (9a) is heated and melted. Synthetic resin is injected at a high pressure to mold the injection-molded product (22), the first core moving means is operated, the first piston (3a) is advanced, and the injection-molded product (22) is applied. When the thickness of the film is pressed and the density of the molded product is homogenized, and the injection molded product (22) is cured, the first movable mold (1a) is retracted, and the injection molded product (22). And a coating material from the first injector (6) into the gap provided between the second fixed mold (1d) and the injection molded product (22). Injecting, and
A step of retracting the second movable mold (1c) when the injection molded product (22 ') is cured to obtain a finished injection molded product (22 ").

The invention according to an eleventh aspect is the injection molding method according to the tenth aspect, in which the second core moving means is operated to press the second core (2b) to thereby produce an injection molded product (22 '). By the re-pressing step of pressing the covering material and the re-pressing step, a gap is provided in the back surface portion (22b) of the injection molded product (22 ′), and the covering material is injected into the gap from the second injector (7). The injection process
Furthermore, it is characterized by including.

  The invention according to claim 12 is the injection molding method according to claim 10, wherein the first injection mold (11a) arranged in one of the two is formed by injecting a synthetic resin to form an injection molded product. The second injection mold (11b) arranged on the other side is in charge of the molding process to be performed, and is in charge of the coating process of applying the coating material to the injection molded product (22).

According to the first aspect of the present invention, the core forming the cavity is provided with the core moving means, so that the re-pressurization and coating of the injection-molded product with the movable mold and the fixed mold closed. Since the injection of the material is possible, instead of moving the conventional movable mold, the smaller core is moved, so that there is an energy saving effect and the mass is small, so that the processing speed and productivity can be improved.
In addition, the conventional mold has a problem that the coating material leaks out of the mold because the coating material is applied by opening one end as small as the thickness of the coating film. Since the coating material can be applied in the closed state, the paint does not leak out of the mold, and a decrease in the mold temperature can be prevented.
Furthermore, the energy loss can be minimized by providing the core moving means in the movable mold closest to the core. Moreover, since the surface of the injection molded product becomes smooth and glossy, and the strength increases, the quality of the injection molded product can be improved.

  According to the invention of claim 2, the core moving means includes a plurality of cylinders in which a plurality of piston rods are passed through a cylinder disposed in either the movable mold or the fixed mold. Thus, by combining a plurality of cylinders, it is possible to select from a predetermined moving distance of the core, and it is possible to reliably move with high precision to the selected specified moving distance. Further, it is possible to provide a core moving means that can move the core with a simple configuration.

  According to the invention of claim 3, since each injector is provided in the immediate vicinity of the covering molding surface to be coated, the injection pressure can be controlled with high accuracy, the quality of the injection molded product is improved, and the mold The temperature management of is easy.

According to the invention of claim 4, since the injection molded product is pressed with the movable mold and the fixed mold closed after the injection molding, the density in the injection molded product can be homogenized and the distortion is eliminated. As well as being able to produce a product without warping and deformation, the smoothness, gloss and strength of the molding surface are improved, and the quality is improved.
In addition, injection molding in which the covering material is coated in a state where the movable mold and the stationary mold are closed can be performed, and a decrease in mold temperature can be prevented. In addition, as compared with the conventional mold that moves the movable mold, since it can be performed only by moving the small core, the processing speed can be improved and the productivity can be improved. Furthermore, by pressing the injection molded product, it is possible not only to secure the thickness of the coating film but also to homogenize the density of the molded product.

According to the invention which concerns on Claim 5, the stage which the product hardened | cured after injection molding by including the re-pressing process which act | operates a core moving means, presses a core, and presses the coating material of an injection molded product Even when the covering material is injected, an injection molding method can be provided in which the outer surface of the molded product, the smooth surface and the glossy surface of the side end portion are improved, and the strength is improved.
In addition, by further including a step of providing a gap in the back surface of the injection molded product and injecting a coating material into the gap in the back surface portion, the outer surface of the injection molded product and the back surface of the injection molded product are placed in the same mold. Injection molding can be performed to cover the coating material, which can reduce the cost of mold production, improve the quality of the injection-molded product, and improve the productivity by increasing the speed.

  According to the invention of claim 6, the injection molded product is a synthetic resin, and the coating material is a thermosetting resin, so that the outer surface of the injection molded product is excellent in smoothness, gloss, strength, and durability. Therefore, it is convenient for an automobile outer plate member. Further, in the case of an automobile outer plate member, the covering of the side end surface is also a high quality point, which is convenient.

According to the invention which concerns on Claims 7-11, the suitable temperature of the shaping | molding process which injects a thermoplastic synthetic resin and shape | molds an injection-molded article is 70-80 degreeC (However, when shaping a thermosetting synthetic resin. The appropriate temperature of the molding process is 150 to 170 ° C.), and the appropriate temperature of the coating process for applying the coating material to the injection-molded product is 120 to 140 ° C., with a temperature difference of about 50 ° C. Therefore, by arranging the molds in parallel and dividing the process, it becomes easier to manage the temperature at the optimum temperature for each process, and by arranging the molds in parallel, injection molded products Temperature drop can be minimized. In addition, since two injection molds are provided side by side, the conventional process can be performed in two steps, and an injection-molded product can be obtained for each shot, improving productivity twice. can do.
Further, an injection mold for the injection-molded product and a coating mold for applying the coating material are provided separately, and the second cavity of the coating mold is compared with the first cavity of the injection mold, and the coating material As a gap for injection, it can be made larger by 20 to 200 μm, and not only can the gap of the covering material in the flat portion be ensured, but also a sufficient gap for injection of the covering material can be ensured on the standing wall surface.

<First embodiment>
Hereinafter, a first embodiment of the present invention will be described with respect to an injection mold and an injection molding method with reference to the drawings. FIG. 1 shows a mold of a mold clamping device of an injection molding machine, and is a cross-sectional view of an injection mold 1 for applying a coating material after injection molding. In addition, in above-mentioned FIG. 9, FIG. 10, since the structure of the injection molding machine was demonstrated in detail, the overlapping description is abbreviate | omitted.
As shown in FIG. 1, the injection mold 1 includes a movable mold 1a and a fixed mold 1b. The mold clamping device 110 of the injection molding machine 100 presses the movable mold 1 a against the fixed mold 1 b to perform mold clamping, thereby forming the cavity 9.

  As shown in FIG. 1, the movable mold 1 a is provided with a cylinder 3, and a piston 3 a is fitted to the cylinder 3. Further, a screw portion 3b is formed at the tip of the piston rod of the piston 3a. Further, a core 2 is disposed in a space formed by the movable mold 1a and the fixed mold 1b, and a cavity 9 is formed. The threaded portion 3b of the piston rod of the piston 3a is screwed to the core 2 and fixed integrally. The core 2 is movable in the left-right direction within the cylinder 3. In addition, illustration of a sealing member etc. is abbreviate | omitted. A cavity 9 in the form of an injection molded product is formed from the movable mold 1a, the fixed mold 1b, and the core 2, and a sprue 8 for injecting a molten synthetic resin material is formed above the cavity 9. Is arranged.

  A first injector 6 for surface coating for coating the outer surface of the injection-molded product 22 is disposed below the fixed mold 1b, and an injection hole 6a is formed. Furthermore, a second injector 7 for back surface coating for coating the back surface (end surface) of the injection-molded product 22 is also disposed below the movable mold 1a, and an injection hole 7a is formed.

The core moving means will be described. 8A is an enlarged cross-sectional view in which the cross section shown in FIG. 1 is enlarged, and FIG. 8B is a left side view thereof. As shown in FIG. 8 (a), when the completed injection-molded product (22) is simply extracted, the piston 3a of the cylinder 3 is moved through the stroke and the core 2 is moved. The core moving means is a means for moving the core 2 for the thickness of the coating film that is a coating material.
As shown in FIG. 8 (b), an intermediate cylinder 30 and a plurality of small cylinders 31, 32,... Are newly provided on the end surface of the movable mold 1a, and these cylinders 30, 31, 32,. By operating, the stroke can be moved and the combination of multiple cylinders can be selected from the predetermined movement distance of the core, ensuring high accuracy with the selected specified movement distance You can move. Further, it is possible to provide a core moving means that can move the core with a simple configuration.
That is, in order to move the piston 3a of the cylinder 3 corresponding to the thickness of the covering material, for example, 100 μm, an oil amount necessary for the movement of the piston 3a may be supplied into the cylinder 3.
For example, when the inner diameter φD of the cylinder 3 is 200 mm, the area is 31400 mm ² , and therefore the volume p of the amount of oil required to move the piston 20 μm is 628 mm ³ (31400 mm ² × 20 μm).
The volume s of the oil amount required for the movement of the piston 100 μm is 3140 mm ³ (31400 mm ² × 100 μm).

As shown in FIG. 8B, the middle cylinder 30 is arranged at the center, and the middle cylinder 30 is for moving 100 μm, for example. In addition, five small cylinders 31, 32, 33, 34, and 35 having a small diameter are arranged around the cylinder. These small cylinders 31, 32, 33, 34, and 35 are each for, for example, 20 μm movement. It is.
Therefore, when the middle cylinder 30 makes one stroke, as shown by a two-dot chain line in FIG. 8A, when the piston rod corresponding to the volume s of 3140 mm ³ is projected, the piston 3a moves by 100 μm. Further, when the small cylinder 31 around it makes a stroke, when one piston rod corresponding to a volume p of 628 mm ³ is projected, the piston 3a moves by 20 μm per one.
That is, since the thickness of the coating film is 20 to 200 μm, the piston 3a can be changed to 20 to 200 μm by combining the middle cylinder 30 and the small cylinders 31, 32, 33, 34, and 35 in this way. The amount of movement can be controlled by simple control. This is called core moving means.
Therefore, according to this core moving means, in the case of a coating thickness of 20 μm, it is possible to realize a coating thickness of 20 μm by driving one small cylinder 31, which is 200 μm. In the case of the coating thickness, it is possible to accurately realize a coating thickness of 200 μm by driving the middle cylinder 30 and the five small cylinders 31, 32, 33, 34, and 35. .

For example, if the diameter of the piston rod 30b of the middle cylinder 30 is φ20 mm and the stroke amount is 10 mm, the volume s shown in FIG. 8 corresponds to exactly 3140 mm ³ . Further, if the diameter of the piston rod 31b of the small cylinder 31 is, for example, φ10 mm and the stroke amount is 8 mm, the volume p shown in FIG. 8 corresponds to just 628 mm ³ . Thus, the cylinder diameter and stroke amount may be determined in accordance with the inner diameter φD of the cylinder 3.

Here, an injection molding method according to claims 4 and 5 will be described with reference to FIG.
(A)-(g) of FIG. 2 is process drawing which shows each process order of the metal mold | die attached to the mold clamping apparatus of the injection molding machine of this invention.
(A) shows a 1st process, the movable mold 1a is arrange | positioned at the left side, the fixed mold 1b is arrange | positioned at the right side, and the core 2 and the cylinder 3 are arrange | positioned at the movable mold 1a. In the first step, the movable mold 1a moves forward (moves from left to right in the figure) by a mold clamping cylinder (not shown).
(B) shows a 2nd process and the movable metal mold | die 1a is pressed by the stationary metal mold | die 1b, and closes. As a result, a cavity 9 is formed in the movable mold 1a and the fixed mold 1b.
(C) shows a third step, in which a synthetic resin heated and melted in the cavity 9 is injected at a high pressure to mold an injection molded product 22.
(D) shows a 4th process, operates a core moving means (refer FIG. 8), advances piston 3a and the core 2, and, thereby, moves the core 2 to the fixed mold 1b side. Thus, the thickness of the coating film of the injection molded product 22 is pressed and the density of the molded product is made uniform. Thereafter, the piston 3a is retracted by the thickness of the coating film to form a gap.
(E) shows a fifth step, in which a coating material is injected into a gap provided between the fixed mold 1b and the injection molded product 22 '.
Further, a re-pressing step is performed in which the core moving means is re-actuated to press the core 2 and press the covering material of the injection molded product 22 ′.
(F) shows a sixth step, in which a gap is provided in the back surface portion of the injection molded product 22 'by the re-pressing step described above, and a coating material is injected into the gap in the back surface portion.
(G) shows the seventh step. When the coating material of the injection molded product 22 'is cured, the movable mold 1a moves backward, separates the runner 21, and obtains a finished injection molded product 22 ".
The injection molded product 22 may be an automobile body outer plate member. In this case, the injection molded product 22 is preferably a thermoplastic resin.

<Second Embodiment>
FIG. 3 shows a mold attached to a mold clamping device of an injection molding machine according to the second embodiment, and is a cross-sectional view of an injection mold in which a coating material is applied after injection molding. 1 and 2 show the mold clamping cylinder with a horizontal injection molding machine, but FIG. 3 shows a configuration in which the mold clamping cylinder is vertically formed. Thus, you may make it vertical.
As shown in FIG. 3, the injection mold 10 is composed of a movable mold 1a and a fixed mold 1b in the same manner as the injection mold 1 described above. The major difference is that the movable mold 1a shown in FIG. 1 is a fixed mold 1b, and a cylinder 3 is provided in the fixed mold 1b. The same components as those already described with reference to FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.
Here, the fixed mold 1b is placed on the base 5 to form a fixed mold. However, the base 5 may be reversed as the tip of the piston rod of the clamping cylinder. The mold 1b is a movable mold 1a, and the movable mold 1a is a fixed mold 1b.

<Third Embodiment>
FIG. 4 shows a mold attached to a mold clamping device of an injection molding machine according to a third embodiment, and is a cross-sectional view of an injection mold in which a coating material is applied after injection molding. As in FIGS. 1 and 2, the clamping cylinder is a horizontal injection molding machine.
As shown in FIG. 4, the injection mold 11 is different from the above-described injection mold 1 in addition to the first movable mold 1a and the first fixed mold 1b. The second movable mold 1c and the second fixed mold 1d are provided. That is, the upper first injection mold 11a is a mold for performing injection molding, and the lower second injection mold 11b is a mold for applying a coating material. Thus, there is a big feature in the division of work processes.
In addition, the same structure already demonstrated in FIG. 1, FIG. 2 is attached | subjected the code | symbol with the upper stage as 1st, and the lower stage as 2nd, and the overlapping description is abbreviate | omitted.

As shown in the upper diagram of FIG. 4, the upper first injection mold 11a of the injection mold 11 includes a first movable mold 1a and a first fixed mold 1b.
The first movable mold 1a is provided with a first cylinder 3, and a first piston 3a is fitted into the first cylinder 3. A first screw portion 3b is formed at the tip of the piston rod of the first piston 3a. Further, a first core 2a is disposed in a space formed by the first movable mold 1a and the first fixed mold 1b. Further, the first screw portion 3b of the piston rod of the first piston 3a is screwed to the first core 2a and is fixed integrally therewith. The first core 2 a is movable in the left-right direction by the flow of high-pressure oil into the first cylinder 3. A first cavity 9a in the form of an injection molded product 22 is formed from the first movable mold 1a, the first fixed mold 1b, and the first core 2a, and a melt is formed on the upper portion of the first cavity 9a. A sprue 8 for high-pressure injection of the synthetic resin material is disposed.

As shown in the lower part of FIG. 4, the second injection mold 11b at the lower stage of the injection mold 11 is composed of a second movable mold 1c and a second fixed mold 1d.
The second movable mold 1c is provided with the second cylinder 4 as described above, and the second piston 4a is fitted into the second cylinder 4. A second screw portion 4b is formed at the tip of the piston rod of the second piston 4a. Further, a second core 2b is disposed in a space formed by the second movable mold 1c and the second fixed mold 1d. Further, the second screw portion 4b of the piston rod of the second piston 4a is screwed to the second core 2b and fixed integrally therewith. The second core 2b is movable in the left-right direction by the flow of high-pressure oil into the second cylinder 4.

  A first injector 6 for surface coating for coating the outer surface of the injection molded product 22 is disposed below the second fixed mold 1d, and an injection hole 6a is formed. Further, a second injector 7 for back surface coating for coating the back surface (end surface) is also disposed below the second movable mold 1c, and an injection hole 7a is formed.

As shown in FIG. 4, comparing the upper first cavity 9a and the lower second cavity 9b, the second cavity 9b is formed to be larger than the thickness of the coating film by coating, for example, a predetermined 100 μm. Yes. Therefore, a gap corresponding to the thickness of the coating film is secured by transferring the injection molded product 22 to the second cavity 9b.
Further, the second cylinder 4 provided in the second movable mold 1c at the lower stage compresses the molding resin to make the thickness of the coating film uniform, and the outer surface of the molded product and the smooth surface and gloss of the side edges. Improve the surface. Furthermore, the strength is improved.

Here, an injection molding method according to claim 10 will be described with reference to FIGS.
(A)-(d) of FIG. 5 is process drawing which shows each process of the first half of the injection mold of this invention. (A)-(d) of FIG. 6 is process drawing which shows each process of the second half of the injection mold of this invention.
As shown in FIG. 5, the first movable mold 1a and the second movable mold 1c are integrated and move together. However, since the explanation is complicated, the upper part in FIG. The lower part will be explained.
The first half process will be described. As shown in FIG.
The upper stage of (a) shows the first step, the first movable mold 1a is arranged on the left side, and the first core 2a and the first cylinder 3 are arranged on the first movable mold 1a. In the first step, the first movable mold 1a moves forward (from left to right in the figure) by a mold clamping cylinder (not shown).
The upper part of (b) shows the second step, in which the first movable mold 1a is pressed by the second fixed mold 1b and closed. As a result, a first cavity 9a is formed in the first movable mold 1a and the first fixed mold 1b.
The upper part of (c) shows the third step, in which the synthetic resin heated and melted is injected into the first cavity 9a at a high pressure to mold the injection molded product 22.
The upper part of (d) shows the fourth step, in which the first core moving means described above is operated (see FIG. 8), the first piston 3a is advanced, and the thickness of the coating film of this injection molded product 22 And a uniform injection-molded product 22 without warping and distortion, by pressing the molded product 22 uniformly.
The first injection mold 11a, which is the upper stage of the injection mold 11, repeats the first to fourth steps. That is, the third to fourth steps of the first injection mold 11a are linked together with the fifth to eighth steps of the second injection mold 11b at the lower stage.

As shown in FIG.
(A) The upper and lower stages show the fifth step. When the injection molded product 22 is cured, the first movable mold 1a is retracted, the injection molded product 22 is discharged, and the discharged injection molded product 22 is discharged to the lower stage. Move and set to the second movable mold 1c. The runner 21 is also separated.
The lower part of (b) shows the sixth step, in which the coating material is injected from the injection hole 6a of the first injector 6 into the gap provided between the second fixed mold 1d and the injection molded product 22.
Furthermore, a re-pressing step is performed in which the second core moving means is reactivated to press the core 2b and press the covering material of the injection molded product 22 ′.
The lower part of (c) shows the seventh step. By the re-pressing step, a gap is provided in the back surface portion 22b of the injection molded product 22 ', and the covering material is injected into the gap from the injection hole 7a of the second injector 7. To do.
The lower part of (d) shows the eighth step. When the injection molded product 22 'is cured, the second movable mold 1c is retracted to obtain a finished injection molded product 22 ".
Thereafter, the process returns to the sixth step (b), and another step is completed by repeating the seventh step (c) and the eighth step (d). That is, thereafter, by repeating the sixth to seventh to eighth steps, the injection molded product 22 ″ is completed one after another.
The injection molded product 22 ″ may be an automobile body outer plate member. In this case, the injection molded product 22 ″ is preferably a thermoplastic resin.
5 and 6, the injection molded product 22 is an injection molded product before coating, and the injection molded product 22 ′ is a coated injection molded product. The injection molded product 22 ″ was easily distinguished as a finished injection molded product.
Further, a molded product that does not require painting on the back surface may be a finished product by an injection molded product 22 '. At this time, the coating process on the back surface can be omitted.

<Fourth embodiment>
FIG. 7 shows a mold of a mold clamping device of an injection molding machine according to a fourth embodiment, which is a cross-sectional view of an injection mold in which a coating material is applied after injection molding, and (a) shows a closed state. Sectional drawing which shows, (b) is sectional drawing which shows the open state. While FIG. 6 shows the mold clamping cylinder with a horizontal injection molding machine, FIG. 7 shows a configuration in which the mold clamping cylinder is vertically formed. Thus, you may make it vertical.
As shown in FIG. 7, in the same way as the above-described injection mold 11, the injection mold 12 includes a first movable mold 1a, a first fixed mold 1b, a second movable mold 1c, and a second fixed mold. It consists of a mold 1d. The major difference is that the first cylinder 3 is provided in the fixed mold 1b and the second cylinder 4 is provided in the fixed mold 1d. In addition, the same code | symbol is attached | subjected to the same structure already demonstrated in FIG. 6, and the overlapping description is abbreviate | omitted.

As shown in FIG. 7, the left mold and the right mold are substantially the same in appearance, but the second cavity 9b of the right mold is the first cavity 9a of the left mold. Compared to the thickness of the coating film, it is formed larger in order to ensure a gap of, for example, about 20 to 200 μm. By doing in this way, a 4th process can be deleted.
The first fixed mold 1b on the left side is provided with a first cylinder 3 for compressing the molding resin, ensuring the thickness of the coating film of the injection molded product, and homogenizing the density of the injection molded product. ing. The first cylinder 3 is fitted with a piston 3a, and a threaded portion 3b is formed at the tip of the piston rod of the piston 3a.
Further, the first core 2a is disposed in the first cavity 9a, and the screw portion 3b of the piston rod of the piston 3a is screwed to the first core 2a and fixed integrally therewith.
The first core 2 a is movable up and down by the flow of high-pressure fluid into the first cylinder 3.
Here, as described above, the fixed molds 1b and 1d are placed on the base 5 to form the fixed mold. However, the base 5 is turned upside down and the base 5 is used as the tip of the piston rod of the clamping cylinder. In this case, the fixed molds 1b and 1d are movable molds 1a and 1c, and the movable molds 1a and 1c are fixed molds 1b and 1d.

The present invention can be variously modified and changed within the scope of its technical idea. For example, although the cylinder 3 is disposed in the movable mold 1a, as shown in the drawing, it may be projected outward without being incorporated, and the piston rod may be a rod on both ends.
In addition, the arrangement and the number of the large cylinders 30 and the small cylinders 31, 32... Are not limited to this, and other sizes may be used, and the number may be increased.
Further, here, the piston rod is projected directly to the cylinder 3, but another piece may be provided so that this another piece projects.
Furthermore, it may be a method in which it is always projected oppositely and immersed.
Further, as another method for controlling the position of the core 2, a position control servo valve may be provided. When this position control servo valve is adopted, in addition to this, a linear scale attached to the cylinder and a hydraulic equipment assembly such as a feedback control amplifier (controller) may be provided as a core moving means for finely moving the core. .
Further, an NC control method combining a servo motor and a ball screw may be used as the core moving means. For example, assuming that the size of the workpiece W is 700 × 1050 mm, if one ball screw is arranged at a ratio of 1000 mm ² , the number is 74. In this way, the core may be moved by multi-axis control provided with a plurality of ball screws.

It is a sectional view of an injection mold which shows a metal mold of an injection molding machine of the present invention and coats a covering material after injection molding. (A)-(g) is process drawing which shows each process. It is sectional drawing of the injection mold which shows the metal mold | die of the injection molding machine of 2nd Embodiment, and coat | covers a coating material after injection molding. It is sectional drawing which shows the metal mold | die of the injection molding machine of 3rd Embodiment, and shows the structure of an injection molding machine. (A)-(d) is process drawing which shows each process of the first half of the injection mold of this invention. (A)-(d) is process drawing which shows each process of the second half of the injection mold of this invention. The mold of the mold clamping device of the injection molding machine of 4th Embodiment is shown, It is sectional drawing of the injection mold which apply | coats a coating material after injection molding, (a) is sectional drawing which shows the closed state, (B) is sectional drawing which shows the open state. The core moving means is shown, (a) is an enlarged cross-sectional view enlarging the cross section shown in FIG. 1, (b) is a left side view thereof. It is a front view which shows the conventional injection molding machine. It is an expanded sectional view of the a part shown in the conventional FIG.

Explanation of symbols

1, 10, 11, 12 Injection mold 1a Movable mold (first movable mold)
1b Fixed mold (first fixed mold)
1c Second movable mold 1d Second fixed mold 2 Core 2a First core 2b Second core 3 Cylinder (first cylinder)
3a Piston (first piston)
3b Screw part (first screw part)
4 Second Cylinder 4a Piston 4b Threaded Part 5 Base 6 First Injector 6a First Injection Hole 7 Second Injector 7a Second Injection Hole 8 Sprue 9 Cavity 9a First Cavity 9b Second Cavity 11a First Injection Mold 11b First 2 Injection mold 22, 22 ', 22 "Injection molded product 30 Medium cylinder 30a Medium piston 30b Medium piston rod 31, 32, 33, 34, 35 Small cylinder 31a, 32a, 33a, 34a, 35a Small piston 31b, 32b , 33b, 34b, 35b Small piston rod

Claims (12)

It is composed of a movable mold and a fixed mold, and a synthetic resin is injected by applying clamping pressure in the mold, and after molding, a coating material is injected into the mold to inject the surface of the injection molded product into the mold. In the injection mold to coat,
A core disposed in one of the movable mold and the fixed mold to form a cavity;
A core moving means for moving the core horizontally;
An injection mold characterized by comprising:   The core moving means includes a plurality of cylinders in which a plurality of piston rods having different lengths are passed through a cylinder disposed in either the movable mold or the fixed mold. The injection mold according to claim 1. The fixed mold is provided with a first injector that covers an outer surface of an injection molded product,
The injection mold according to claim 1, wherein the movable mold includes a second injector that covers a back surface of an injection molded product. It is composed of a movable mold and a fixed mold, and a synthetic resin is injected by applying clamping pressure in the mold, and after molding, a coating material is injected into the mold to inject the surface of the injection molded product into the mold. In the injection mold to coat,
Injection molding that is injection-molded by an injection mold that includes a core that is arranged in one of the movable mold and the fixed mold to form a cavity, and a core moving means that moves the core horizontally. A method,
A step of moving the movable mold forward;
The movable mold is pressed against the fixed mold and closed, and a cavity is formed;
A step of high-pressure injection of a synthetic resin heated and melted into the cavity, and molding an injection molded product;
Actuating the core moving means to advance the piston, pressing the thickness of the coating film of the injection molded product and homogenizing the density of the molded product, and then retracting the core to form a gap; and ,
Injecting a coating material into a gap provided between the fixed mold and the injection-molded product;
After curing the injection-molded product, a step of retracting the movable mold to obtain a finished injection-molded product;
An injection molding method comprising: A re-pressing step of re-activating the core moving means to press the core and pressing the coating material of the injection molded product;
By the re-pressing step, a gap is provided in the back surface portion of the injection molded product, and an injection step for injecting a coating material into the gap in the back surface portion,
The injection molding method according to claim 4, further comprising:   The injection molding method for an automobile body outer plate member according to claim 4 or 5, wherein the injection molded product is made of a synthetic resin, and the covering material is a thermosetting resin. The first injection mold includes a first core disposed in the first movable mold or the first fixed mold,
A first cavity formed by the first core;
First core moving means for moving the first core horizontally;
Consisting of
In the second injection mold, the second movable mold or the second fixed mold has a second core built therein as described above, and a second cavity is formed.
Second core moving means for moving the second core horizontally;
2. The injection mold according to claim 1, wherein the first injection mold and the second injection mold are arranged vertically or in parallel on the left and right.   8. The injection mold according to claim 7, wherein the first injection mold is a synthetic resin mold, and the second injection mold is a coating mold.   9. The injection mold according to claim 8, wherein the second cavity of the second injection mold is made larger by 20 to 200 [mu] m than the first cavity in order to ensure a gap between the covering materials. The first injection mold includes a first core disposed in the first movable mold or the first fixed mold, a first cavity formed by the first core, and the first A first core moving means for moving the core horizontally, and the second injection mold is the second movable mold or the second fixed mold in the same manner as the second center. And a second core moving means for moving the second core horizontally, wherein the first injection mold and the second injection mold are arranged vertically. Or an injection molding method in which injection molding is performed with injection molds arranged in parallel on the left and right,
A step of advancing the first movable mold;
The first movable mold is pressed against the first fixed mold and closed;
A step of injecting a synthetic resin heated and melted into the first cavity at a high pressure to form an injection-molded article;
Actuating the first core moving means, advancing the first piston, pressing the thickness of the coating film of the injection molded product, and homogenizing the density of the molded product;
When the injection-molded product is cured, the first movable mold is retracted, and the injection-molded product is set in the second movable mold.
Injecting a coating material from the first injector into a gap provided between the second fixed mold and the injection molded product;
When the injection molded product is cured, the second movable mold moves backward to obtain a finished injection molded product;
An injection molding method for covering an injection-molded article, comprising: Re-pressing step of actuating the second core moving means, pressing the second core and pressing the coating material of the injection molded product;
By the re-pressing step, a gap is provided in the back surface portion of the injection molded product, and an injection step of injecting the coating material from the second injector into the gap,
The injection molding method according to claim 10, further comprising:   The first injection mold is in charge of a molding process for injecting a synthetic resin to form an injection molded product, and the second injection mold is in charge of a coating process for applying a coating material to the injection molded product. The injection molding method according to claim 10.

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