JPS63270112A - Mold - Google Patents

Abstract

PURPOSE:To shorten cycle time by enabling saving in a molding material, by a method wherein injection molding of a large number of molded products is performed simultaneously by a hot runner system, gate cut is performed by a punch after molding and a sprue communicating with a cavity is shortened. CONSTITUTION:Molten resin is pressed in through a nozzle 19 of a molding machine under a state where a stationary side and movable side molding parts 3, 4 have been brought close to each other. The pressed-in molten resin is pressed into sprues 8, 8 of sprue bushings 9, 9 through a hot sprue 18, runner 17a and hot nozzles 16, 16 and cavities 5, 5 are filled with the molten resin. After the lapse of predetermined dwell time, dwell is released, cooling is effected for a predetermined period of time and the molten resin within the cavities 5, 5 and sprues 8, 8 is solidified. Piston rods 24, 24 of air cylinders 23, 23 are moved backward in the direction of an arrow 28b. When a space is generated among spacers 26, 26 and a fitting plate 22 and a punch 12 is moved forward in the direction of an arrow 32a, the nozzle 19 of the molding machine is moved backward in the direction of the arrow 32a by amount of the space and the solidified molded bodies 33, 33 and sprue parts 34, 34 are separated by the punch 12 from one other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a mold for injection molding, for example, an optical disk.

(Prior Art) Optical disks as storage media have characteristics such as large storage capacity, low cost per bit, and excellent operability. These optical discs are made by injection molding, but because they are required to transfer minute bits and groups and have low distortion without optical anisotropy, they are basically single-cavity discs. Precision molding method is used.

However, the single-piece method has extremely poor productivity;
It does not adapt to the smaller diameter of optical disks, and is an obstacle to cost reduction. Therefore, a multi-cavity molding system for optical discs is required. However, with conventional molds, it has not been possible to simultaneously injection mold a plurality of optical disks and to punch out the center hole of the molded optical disks smoothly.

(Problems to be Solved by the Invention) The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a mold that allows efficient injection molding of optical discs.

[Structure of the invention] (Means and effects for solving the problem) Hot 2-na
This is a mold that simultaneously injection molds multiple molded products using a system and performs a gate cut using a punch after molding.By shortening the sprue that communicates with the cavity, it is possible to save molding material. This shortens the cycle time.

(Example) Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

The drawing shows the mold of this example. This mold is
Two mutually juxtaposed disc forming parts (1).

(1) and a resin supply section (2) that simultaneously supplies molten resin to these disk molding sections. However,
The disk molding part (1) is a fixed side molding part (3) which is fixedly installed.
), and a movable molded part (4) that is provided so as to be able to move toward and away from the fixed molded part (3). The fixed-side molding part (3) is a cylindrical fixed-side molding part (3) in which a disc-shaped cavity (5) in which an optical disc is molded is recessed.
6) and the fixed side template (6) on which this nest (6) is held.
The force and the guide (7) for this spruop trousers are
), and has a sprue (9) having a sprue (8) and opening one end of the sprue (8) into the center of the cavity (5). On the other hand, the movable side molded part (4) is a cylindrical movable side nest OI provided so as to be able to move toward and away from the stationary side nest (6).
J, a punch guide aυ fitted and fixed to this movable nest α [, a cylindrical punch α2 slidably fitted to this punch guide <11), and a punch that is coaxial with and fixed to this punch (13). It has an ejector bin Q3 slidably fitted into the punch α2, and a ring-shaped stamper presser α4 inserted through the punch guide C1υ so as to be exposed to the parting surface α of the nest at1. Therefore, the resin supply section ae is connected to the hot nozzles αQ and αe fitted to the upper ends of the sprue bushes (9) and (91) of the pair of disk molding sections (1) and (1), respectively. Hot nozzle α
e, a manifold block housing η having a bifurcated runner (17a) communicating with The machine nozzle (I!lI), the connecting bar ■... that fixes the hot sprue αυ to this machine nozzle a3 via a heat insulating plate (20...), and this machine nozzle (IIK movement guide (21a) The heating cylinder Qυ of the molding machine, which is movably connected to prevent cooling of the molten resin, and the fixed side mounting plate (time), which is fixedly installed on the mold clamping mechanism, and this fixed side mounting plate (
2) A pair of air cylinders Ω and @ are installed at symmetrical positions on both sides of the hot sprue α mark at the bottom of the hot sprue, and these air cylinders C! 3), c! 3 piston rod ■, (2
4) A pair of pressure receiving plates (c) and (c) attached to the tip of
and a pair of spacers (supports) fixed to the manifold block <171 at a position directly below the pressure receiving plate (c) and (2!19).

It has a strong point. Therefore, the lower part of the mounting plate is provided with guide recesses (3) and (27) for guiding the pressure receiving plates (C) and @, and the pressure receiving plates (C) and (C) are guided through these guide recesses α. , @ in the directions of arrows (28a) and (28b). A heater (not shown) is embedded in the manifold block α to prevent assimilation of the molten resin in the runner (17a).

Further, a band heater shield (C30) for preventing assimilation of the molten resin is wrapped around the outer periphery of the hot sprue α inlet and the molding machine nozzle 19. Similarly, a band heater 6υ is also wrapped around the outer periphery of the hot knobs αQ and αQ to prevent assimilation of the molten resin.

In other words, the molding machine heating cylinder Qυ, the molding machine nozzle 0. Hot sprue 081. Runner (17ri) and hot nozzle (I
In Q and ae, the molten resin is always in a molten state.

Next, the operation of the mold of the above embodiment will be described.

First, with the fixed side and movable side molding parts (3, 1, (4) in close contact with each other, molten resin is press-fitted from the molding machine nozzle αl. At this time, the air cylinder (c), the piston of c!3 The rods C24) and (F) are in the forward position (in the direction of arrow (28a)), and the pressure receiving plates (C) and (C) are located at the spacers 弼 and (C).
It is in contact with the manifold block αη via (g).

The press-fitted molten resin is then transferred to the hot sprue α, the runner (17) and the hot nozzle (1119, αe).
The molten resin is press-fitted into the sprue (8), (81) of the sprue bush (91, (9)) through the
δ Blue (8).

The cavities (5) and (5) are filled from (8). Then, after a predetermined holding pressure period has elapsed, the holding pressure is released and the cavities (5), (5) are cooled for a predetermined period of time.
and sprue (81, (the molten resin in 81 is solidified. Next, the air cylinder (c), the piston rod r24 of (23)).

C4l is retreated in the direction of arrow (28b). the result,
The pressure receiving plates (C) and (C) slide inside the guide recesses ■ and @, and there is a space between the spacer (A) 9g5 and the mounting plate (2) for the pressure receiving plates (C) and (C). occurs. Therefore, when the punch (121) is moved forward in the direction of the arrow (32a), the sprue bush (91, +9), the hot nozzle σe,
(Le, through the manifold block (17) and the hot sprue, the molding machine nozzle σl is connected to the spacer (c)
, (a) and the space of the mounting plate e3 in the direction of the arrow (32). Then, the solidified molded bodies (2), (c) and the sprue parts (2), (b) are moved back by the punch (l). Then, separate the movable side molding part (4) as indicated by the arrow (3).
8b) With the mold opened and retracted in the direction, the ejector bin 0. C3 is driven in the direction of arrow (321) to simultaneously project the pair of sprue portions -1 (b) to the outside. On the other hand, the two disc-shaped molded bodies (G) that will become optical discs are taken out by a take-out machine (not shown).

As described above, the mold of this embodiment allows for simultaneous injection molding of multiple molded bodies (up to) and C13, and subsequent punching of the large central part using the hot runner system. , productivity increases significantly. Furthermore, since the sprue portions (b) and (b) are shortened, molding material is saved, and this effect increases as the number of sprues increases. In addition, since the sprue is short, it is possible to prevent problems such as remaining sprue, and it can be easily taken out without the need for a special takeout machine such as a suction tube, so the amount of mold opening can be reduced. The minimum amount that can be taken out is sufficient, and the mold opening and closing time as well as the unloading time can be shortened, resulting in a shortened cycle time.

Note that the present invention is not limited to disk molding, but is also particularly effective in multi-piece molding using a hot runner system that performs gate cutting within a mold. Furthermore, the drive of the pressure receiving plate is not limited to an air cylinder, and may be hydraulically driven using a hydraulic circuit of an injection molding machine. Further, in the above embodiment, the manifold block (17) is guided for movement by the movement guide for the heating cylinder CI of the molding machine, but a guide may be provided within the mold. Furthermore, although the above-mentioned embodiments illustrate the molded body having two molded bodies, a greater effect can be obtained by molding a plurality of molded bodies, not limited to two molded bodies.

〔Effect of the invention〕

By using the mold of the present invention, without using a hot runner system, a large number of injection moldings and subsequent gate cutting can be performed simultaneously, and productivity is significantly improved. Since a portion of the sprue can be shortened, material costs can be saved, and removal from the mold can be performed reliably and easily, resulting in a significant reduction in cycle time.

[Brief explanation of the drawing]

The drawing is a sectional view of a main part showing the configuration of a mold according to an embodiment of the present invention. (1): Disc molding part, (5): Cavity, (8
) Varnish blue, (9) Varnish blue bush, C2: Punch, αQ: Hot nozzle, αη
: Manifold block, (17a): Runner, C8
: Hot sprue, C1l: Molding machine nozzle, (c): Pressure receiving plate, @varnish spacer.

Claims (1)

[Scope of Claims] A mold characterized by having the following configuration. (a) A molding section that can be opened and closed and has multiple cavities in which molded products are injection molded. (b) A plurality of punches that are provided in the molding section so as to be able to move in and out of each of the cavities and punch out the molded product in the cavities. (c) A plurality of sprue bushes are provided in the molding section to face each of the punches and to freely follow the protrusion movement of each of the punches toward the cavity, and to supply molten resin to each of the cavities. (d) A plurality of hot nozzles that are integrally and movably connected to each of the sprue bushes and supply molten resin to these sprue bushes. (e) A manifold block provided with a runner that is integrally movably connected to each of the hot nozzles and serves as a flow path for molten resin to each of the hot nozzles. (f) A hot sprue that supplies molten resin from a nozzle of an injection molding machine, one end of which is integrally movably connected to the manifold block and the other end of which is connected to the runner. (g) Provided on the opposite side of the molding section with the manifold block in between, and restricts movement of the manifold block due to the injection molding pressure, and also controls the sprue bush, the hot nozzle, and the manifold block due to the protrusion of the punch. and a movement regulating means for regulating the movement of the hot sprue.