JPS58107321A - Resin molding die device - Google Patents

Abstract

PURPOSE:To provide a titled device which molds a thin part having an accurate through hole by forming a floating punch and part of a cavity at one end of a punching punch provided at the position corresponding to the floating punch and driving the punches after hardening the resin. CONSTITUTION:The top end of a punching punch 19 is supported to the same plane surface as the upper surface of the cavity 9 of a movable side mold 8, and a floating punch 17 is urged by a spring 18 to the same plane surface as the lower surface of the cavity 9 of a stationary side mold 4. After the injection and filling are completed, a piston rod 23 is lifted in the state that the molds 4, 5 are contacted by the mold clamping force, a resin forming plate 15 is punched and sheared.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold apparatus for resin molding, and more specifically to a mold apparatus for resin molding suitable for molding thin-walled parts having through holes.

In recent years, injection molded products have been used for functional parts that require high precision.For example, as shown in FIG. 1(A), through holes 1a are partially arranged in a relatively thin disk 1. As shown in Figure 1(B), there is a through hole 1a in the thin plate l.
An injection molded product is used for a sliding groove IC such as a fitting part 1b or a lever to which power is distributed.

First, the general configuration of a resin molding mold apparatus for processing this type of molded product will be explained, and its problems will be mentioned.

Figure 2 is a cross-sectional view showing the general configuration of a mold device for resin molding, with (A) showing the state during resin injection and filling, and (B) showing the removal of the molded product. FIG. A fixed side mold 4 is integrally provided on the fixed side bolster 2, and a nozzle hole 5 is provided in the center of the mold 4.
A nozzle tip 6 is provided. An injection gate 7 is bored in the mold 4 at a portion corresponding to the tip of the nozzle tip 6. A movable side mold 8 is attached to the movable side bolster 4.
are integrally provided, and a cavity portion 9 is provided on the distal end surface of the mold 8. An ejector bin 11 for taking out the molded product is provided in the center of the cavity 9 so as to be able to slide up and down, and is fixed to an ejector rod 14 connected to a drive device (not shown) via a plate 12. . The upper end surface of the ejector bin 11 is set to be on the same plane as the cavity portion 9 in the resin injection filling pattern. A protrusion 10 is provided in the cavity 9 in order to form the through hole 1a of the molded product when the cavity 9 is filled with heated and melted resin through the injection gate 7 at a high injection pressure.

When the cavity flI9 is completely filled with resin and the resin temperature has decreased to a predetermined temperature so that the surface layer can be released from the cavity part 9, the movable side bolster is removed as shown in FIG. 2(B). -3 to a predetermined position to open the mold, and then push up the ejector bin 11 with the ejector rod 14 to release and discharge the resin molded body 15.

However, as shown in FIG. 1(A), if there is no through hole, the heated molten resin injected into the cavity 9 from the gate 7 at the center of the disk l will pass through the gate 7 at the center as shown by the arrow on the left half. The resin is evenly and homogeneously diffused in the radial direction. However, when forming the through hole 1a, the protrusion 10 is partially disposed in the cavity 9, so
The filling and diffusion of the resin flows along the outer periphery of the protrusion 10 by changing the flow path in a complicated manner.

For this reason, the packing density between the center side and the outer circumferential side of the protrusion 10 becomes uneven, and when the resin flows merge again on the outer circumferential side of the protrusion 11, a layered uneven layer, so-called flow marks, is generated. Put it away. Then, the mechanical strength at that point decreases, and since there is a difference in the contact area between the cavity part 9 and the resin, the gradient of the temperature drop of the resin becomes uneven, resulting in a decrease in dimensional accuracy and flatness, resulting in a thin plate. Inconveniences such as deformation and warping occurred.

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin molding mold device that solves the above-mentioned problems and is capable of injection molding thin-walled parts having through-holes that require highly precise positioning and dimensions.

In order to achieve the above object, the resin molding mold device according to the present invention is an injection molding device for processing a resin molded product having holes by injecting resin into a cavity space formed by a fixed side mold and a movable side mold. In a molding die apparatus, a separating punch is slidably supported by one of the molds and has one end capable of forming a part of a cavity, and the other mold is provided at a position corresponding to the floating punch. a punching punch whose one end can form a part of the cavity; supporting means for supporting the floating punch so that the end face of the floating punch forms a part of the cavity during resin injection; After the resin to be molded has hardened, the two dies are clamped by a punch driving device that drives the punch downward to shear and punch the resin plate.

That is, in order to uniformly and uniformly diffuse and fill the molten resin from the injection gate to the peripheral area in injection molding of thin-walled parts, it is desirable that there be no protrusions that would obstruct the flow path.

Focusing on this point, in the present invention, obstacles during resin diffusion such as protrusions are not cut, and after completion of diffusion and filling, the fixed mold and the movable mold close the cavity using mold clamping force. The object of the present invention can be completely achieved because the hole is formed by shearing with a punch while the sheet is in the same state.

Hereinafter, the present invention will be explained in more detail with reference to the drawings and the like.

FIG. 3 is a cross-sectional view showing an embodiment of the injection mold device according to the present invention, in which (A) shows the resin-filled stripes, (B) shows the punched state, and (C) shows the resin-filled strips. C is the open state of the mold.
D) is a diagram showing the discharge state. Note that parts having the same functions as those of the conventional device described above are given the same reference numerals.

A stepped space 16 is provided in the stationary mold 4, and a floating punch 17 is slidably provided in a small diameter portion of the serving space 16. A flange portion is provided at the upper end of the floating punch 17, and by being biased downward by a compression spring 18 inserted into the space 16, the flange portion of the floating punch 17 comes into contact with the stepped portion of the space 16. The lower end surface of the floating punch 17 is flush with the lower surface of the stationary mold 4 and forms part of the cavity 9.

The compression spring 18 has sufficient biasing force to prevent the floating bunch 17 from being pushed back upwards when the resin is compressed and filled.

Note that hydraulic pressure or pneumatic pressure can be used for this part as necessary.

The movable mold 8 is provided with a stepped space 21, and in the small diameter portion of the stepped space 21, a punch 19 having the same outline and coaxial with the floating bunch 17 provided in the fixed mold 4 is provided. The punch 19 is provided to be slidable up and down, and the lower end of the punch 19 is connected to a piston rod 23 of a hydraulic cylinder 22 through a mounting plate 20 .

The upper end surface of the punch 19 forms part of the cavity 9 with the lower surface of the mounting surface 20 in contact with the stepped portion of the stepped space 21 .

The hydraulic cylinder 22 is provided below the stepped space 21 and constitutes a punch driving device that drives the punch 19. A piston rod 23 connected to the punch 19 is fitted into the hydraulic cylinder 22 so as to be slidable up and down, and a hydraulic boat 24 for lowering and a hydraulic boat 25 for pushing up the piston rod 2''3 are provided.

Next, the operation of the resin molding mold device according to the present invention is shown in FIG.
This will be explained with reference to A) to (D').

Figure 3 (A) shows the state of mold clamping and resin filling, where the fixed mold 4 and the movable mold 8 are molded by the high pressure of the resin when the resin is injected into the can and tee 9. In order to prevent the mold from opening, a sufficient mold clamping force is applied between the stationary bolster 2 and the movable bolster 3 by a hydraulic device (not shown) so that the mold is tightly fixed. In this state, resin is injected from the injection gate 7 into the cavity portion 9 through the nozzle hole 5 of the nozzle chip 6. At this time, hydraulic cylinder 2
3 is at the bottom dead center position, the upper end of the punch 19 is on the same plane as the upper surface of the cavity part 9 of the movable mold 8,
Similarly, the floating bunch 17 is biased by the compression spring 18 and its lower end is on the same plane as the lower surface of the cavity part 9 of the stationary mold 4, so that it can fit into the hole 1a of the disk 1 as shown in FIG. 1(A). The corresponding portion is filled with resin to form a disc without holes 1a.

FIG. 3(B) shows the state in which the hole 1a is punched out after injection and filling is completed. When injection filling is completed, the fixed side mold 4
The movable mold 8 is brought into close contact with the hydraulic boat 25 by the hydraulic cylinder 22 for lifting.
Hydraulic pressure of a predetermined pressure is supplied from the piston rod 23.
is pushed up, the resin molded plate 15 is punched and sheared, and the floating bunch 17 is retreated, and the punch 19 is pushed up until it comes into contact with the cavity surface of the stationary mold 4, completing the punching. The punching chip 26 is completely pushed up into the stationary die 4. In order to perform this operation,
The upward force of the hydraulic piston rod 23 is applied to the floating bunch 17.
It goes without saying that the force must exceed the pressure of the compression spring 1B and the shear force for punching the resin molded plate 15.

FIG. 3(C) shows the mold opening state and the punching chip ejection state. The punching tip 26 was pushed into the sliding hole of the floating bunch 17 of the stationary mold 4 at the same time as the mold was opened.
The floating bunch 17 is pushed out by the biasing force of the compression spring 18 and is discharged to the outside. Punch punch 19
is lowered by the hydraulic piston loft 23 when the mold opening is completed.

FIG. 3(D) shows the discharge state of the resin molded plate. When the ejector bin 11 is pushed up by the ejector rod 14, the resin molded plate 15 is ejected from the cavity portion 9.

As explained in detail above, the present invention enables uniform diffusion and filling of pressurized molten resin injected into a cavity when producing a thin plate-shaped resin injection molded product having an arbitrary number and arbitrary shape of openings. As is done in this process, a uniform resin plate is molded without any obstacles such as protrusions required for opening molding, and then the fixed side mold and the movable side mold are brought into close contact with each other under pressure to form the desired shape. Since the structure is such that the holes are formed by punching and shearing, the following unique effects are produced.

First, since there are no obstacles when the resin is diffused and filled, the diffusion and filling is performed homogeneously, local density differences can be restricted to a minimum, and the contact surface area between the mold and the resin is uniform. Therefore, the cooling rate becomes uniform, and problems such as non-uniform thickness due to density differences and cooling rate differences, warped deformation of the plane, etc., are solved. This is particularly effective when the resin plate itself is required to have optical refractive index, parallelism, etc.

Furthermore, since there is no deteriorated layer of the molded product caused by the diffusion channels branching off and remerging due to obstacles, the mechanical strength is improved and internal strain is reduced.

In addition, in the case of parts that have a large number of holes and require strict dimensional accuracy between hole positions, punching is performed after the resin has completed diffusion filling and the resin has cooled and surface solidified to the extent that it can be punched. The accuracy of the hole-inner body and the dimensional accuracy between hole positions were significantly improved compared to when molded in a high-temperature molten state.

[Brief Description of the Drawings] Fig. 1 is a diagram showing an example of a thin plate having a through hole, Fig. 2 is a sectional view showing the basic configuration of a conventional resin molding mold device,
FIG. 3 is a cross-sectional view showing an embodiment of the injection mold device according to the present invention, in which (A) shows a resin-filled state, (B) shows a punched state, and (C) shows an embodiment of an injection mold device according to the present invention. (D) shows the mold opening state, and (D) shows the discharging state. 1... Molded product 1a... Opening part 2... Fixed side bolster 3... Movable side bolster 4... Fixed side mold 5... Nozzle hole 6... Nozzle tip 7 ... Injection gate 8 ... Movable side mold 9 ... Cavity part 10 ... Projection part 11 ... Ejector bin 12.
... Mounting plate 13 ... Ejector pin vertical movement space 14 ... Ejector bind 15 ... Molded body 16 ... Spring chamber stepped space 17 ... Floating punch 18 ... Compression spring 19 ...・Punching bunch 20...
・Mounting plate 21...Stepped space 22...Hydraulic cylinder 23...Piston pull-down door 24...Piston pull-down boat 25...Piston push-up port 26...Hole punching chip patent application Person Mitsuo Takahashi Agent Patent Attorney Ino Ro Judai 1m1 (A) (B) r (A'1 (B) Sai'3 CB)

Claims (1)

[Claims] In an injection mold device that injects resin into a cavity space formed by a fixed mold and a movable mold to process a resin molded product having holes, a mold that is slidably supported by one of the molds is used. , a floating punch with one end capable of forming a part of the cavity; a punching punch provided on the other mold at a position corresponding to the floating punch and with one end capable of forming a part of the cavity; supporting means for supporting the end face of the floating punch so as to form part of the cavity; supporting means for supporting the punch so as to form part of the cavity during resin injection; A mold apparatus for resin molding, characterized in that the mold is tightened by a punch driving device which drives the punch downward to shear and punch the resin plate.