JPS62111710A - Metal mold - Google Patents

Abstract

PURPOSE:To enable the titled mold to maintain the form of a cavity at high accuracy and to make form accuracy of a molded article especially a thickness of the same constant, by so constituting the titled mold that a moval side die plate is provided rotatably and simultaneously with mold clamping the moval side die plate and a stationary side die plate are fitted and stuck closely each other. CONSTITUTION:A movable side die plate 4 is moved forward in the direction of an arrow 25 by a mold clamping cylinder 19. A tapered part 14 comes into contact only with the lower part of the tapered surface 21 in the initial stage that the tapered part 14 has been fitted in a guide hollow part 20. Then when a movable side die plate 10 is moved forward further, an inclination of the movable side die plate 10 is corrected by the tapered surface 21 gradually through a spherical seat 6 and spherical part 12. Then when the tapered part 14 is tuck closely to the tapered surface 21 by fitting the tapered part 14 into the guide hollow part 20 completely, a closed thin-plate-like space whose parallelism between the bottom 20a of the guide hollow part 20 and the bottom 13a of a cavity 13 is extremely high is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a mold for injection molding that can reliably make the thickness of thin-walled parts uniform.

[Technical background of the invention and its problems]

To obtain thin-walled plastic parts using conventional injection molding technology, the temperature of the molten resin is raised to ensure high fluidity, and then high-speed injection is performed to fill the molten resin to the end of the cavity. . By the way, in such a case, since high-speed injection is performed, deformation and positional displacement of the mold are likely to occur, which is the main cause of errors in wall thickness accuracy of the molded product. Therefore.

In addition to increasing the rigidity of the mold itself, it is necessary to improve the shape accuracy of the fixed and movable mold plates, mounting plates, and die plates, and to strengthen the mold clamping force to maintain the required parallelism. In this way, desired wall thickness accuracy can be obtained.

In other words, as shown in Figure 45, the fixed side die rate (
A) and a pair of tie bars (B), the perpendicularity between the tie bars (B), (B), the parallelism between the tie bars (B), (B), the straightness of the movable die plate (C), and the movable die plate (C)
Guide bushette (D), which is installed in one piece in (
It was necessary to machine the clearance between D) and tie bars (B) and (B) with high precision.

However, it is extremely difficult to process the template, mounting plate, and die rate with high precision.
The problem is that processing costs are rising. In addition, increasing the mold clamping force has the disadvantage that the mold is easily damaged and the life of the mold is shortened.

[Purpose of the invention]

The present invention has been made by paying attention to the above-mentioned circumstances.

It is an object of the present invention to provide a mold for injection molding that can obtain a desired wall thickness accuracy regardless of the shape accuracy of the mold.

[Summary of the invention]

To support a movable side mold plate through a spherical pair so as to be able to roll freely, and at the same time as mold clamping, the movable side mold plate and the fixed side mold plate are fitted into each other and in close contact to securely position the cavity. It was made so that it could be done.

[Embodiments of the invention] An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the mold of this example. This mold consists of a fixed-side die plate (1) J, which is a plate-shaped fixed-side mounting plate (2) to which one main surface is fixed, and a fixed-side die plate (2) that is fixed to the other main surface of this fixed-side mounting plate (2). A side mold plate (3), a plate-shaped movable side mounting plate (5) fixed to the movable side die plate (4) with one main surface facing the fixed side mold plate (3), and this o
The spherical seat (6
), and this template support (fixed to the movable side mounting plate (5) so as to coaxially surround the force, and having a circular shape at the tip with a diameter smaller than the inner diameter of the main body). A cylindrical template locking body (9) in which an opening (8) is formed.
, an 0T movable side mold plate (10) having one end rotatably held in a spherical pair on the spherical seat (6) and the other end protruding from the opening (8); It consists of a side mold (2) plate a@, a movable side mounting bolt, and an ejector bin ring inserted through the mold plate support (7).
The movable template CIIJ is formed into a cylindrical shape as a whole,
A spherical part (121) is formed at one end to be held in a spherical pair on a spherical seat (6), and the other end has a cavity α3 for obtaining a molded product using the circular thin plate method. A protruding truncated conical tapered portion I is formed.
A flange portion 09 is formed in the middle.

This flange (15) engages with the engaging end (lE9) of the template locking body (9) forming the opening (8), and this template locking body (9) engages with the movable side mold. The plate QQI is held by the template support (to the extent that it can freely roll a small amount without being separated from the force. In other words, the main body aD of the movable template a0 and the opening (8) Between the flange a9 and the template locking body (9)
0, which allows minute rolling of the movable mold plate uC,
A play gap of 2 to 0.6 smoke is provided. Furthermore, a lubricating groove filled with oil to promote lubrication between the first spherical part (1z and the first spherical seat (6)) is carved to ensure smooth rolling of the movable mold plate C11. It is now possible to

Furthermore, the ejector bin (1υ) is installed coaxially with the movable side mold plate (10) and slidably in the axial direction. On the other hand, the fixed side template (3) has a guide recess (to) into which the tapered part I fits when tightening. The guide recess (A) has a concave portion formed between the tapered surfaces where the truncated cone-shaped taper portions come into close contact with each other. (20a
) and the bottom surface (13a3) of the cavity (13) are set so that the parallelism with the bottom surface (13a3) is extremely high.In addition, the fixed side mold plate (3) has a gate (
2 is open at one end into the guide recess Ca. The other end of this gate (24) is connected to one end of the sprue bushing Q fitted to the fixed side mounting plate (2).The other end of this sprue bushing 03 has a nozzle +241. The molten resin is connected to the cavity 0 and injected through the gate 12z. Thus, the movable mounting plate 0Q is moved forward and backward in the directions of arrows C25+ and i26+ by a mold clamping cylinder d9 integrally with the movable die plate (f=4). Namely.

At the tip of multiple parallel round tie bars.

fixed side die play) (1), but its main surface is tie bar 1
It is fixed at an angle of 1 angle to the axis of 271.... The tie bar (27)... is connected to the guide bush C barrel... connected to the mold clamping cylinder Ql.
The l side die plate (4) is slidably attached.

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

First, the movable die plate (4
) in the direction of arrow 06), then move back to the direction of arrow 05).
move forward in the direction. Then, the movable template (10) moves forward together with the stationary template (3).At this time, the movable template (IQ) is inclined downward due to its own weight. In the initial stage when Qυ is inserted into the guide recess 4, it contacts only the lower part of the tapered surface Qυ, as shown in Fig. 2. However, it is possible (1111 template 00).

Further moving forward in the direction of arrow (2), the tapered surface (2] J
As a result, the inclination of the movable mold plate part is gradually corrected via the first spherical seat (6) and the spherical part α2 (see FIG. 3). Then, as shown in FIG. 4, the tapered part (141
When they come into close contact, the bottom tm (20a) of the four guide parts 121 and the bottom surface (13a) of the cavity (19) are extremely parallel, forming a closed thin plate-like space. While maintaining the mold clamping state with the side mold plate 110).

Molten resin is injected into the cavity C131 from the nozzles c2 through the gate (2). Then hold the pressure for a certain period of time.

After solidifying the molten resin, the movable mold plate 00 is moved back in the direction of the arrow by the cylinder σ1 to release the mold clamping.

Next, the ejector pin αυ is advanced in the direction of arrow (c), and the molded product (to) fitted in the cavity (13) is pushed out from the cavity (19).

In this way, the mold of this example has a movable side mold plate (tO)
is rotatable, and a cavity α is provided in the fixed side scattering plate (3).
Since the tapered part (14) where 9 is formed is fitted and positioned, the bottom surface (13a) and the bottom surface (20a)
It is possible to maintain parallelism with high accuracy, and the wall thickness and shape accuracy of the molded product can be maintained stably and constant. In addition, since the mold clamping force is applied to the parting surface through the single spherical pair, the filling impact force accompanying the injection of molten resin is also applied to the die play through the single spherical seat (6) (1)
, (4) Add to the whole mold.

Die plate (1), (41 and tie bar (η...
deformation can be suppressed to a minimum. Furthermore, it is no longer necessary to extremely increase the machining accuracy of the mold and the mold clamping mechanism, reducing machining costs.

In addition, in the above embodiment (in this case, a spherical part (1 piece) is provided on the movable side template (10), and a spherical seat (6) is provided on the template support (7).
However, a spherical seat is provided on the movable side template (1@), and vice versa.

A spherical part a may be provided on the template support (force) to form one spherical pair.
A guide recess having a cavity (14) may be provided in the guide recess, and a convex tapered portion that fits into the guide recess may be provided in the stationary template (3).

〔Effect of the invention〕

The uninvented mold has a movable side mold plate that can be freely rolled.

In addition, since the movable mold plate and the fixed mold plate are fitted into each other and brought into close contact with each other at the same time as the mold is clamped, the shape of the cavity can be maintained with high precision. As a result, the shape accuracy, particularly the wall thickness, of the molded product can be made constant. Furthermore, since the filling impact force accompanying the injection of molten resin is applied to the entire mold via the pair of spherical surfaces, deformation of the mold, die plate, and tie bars can be suppressed. Therefore, the present invention has a special effect when a plate-shaped molded product is injection molded at high pressure and high temperature. Also.

There is no need to make the processing precision of the mold and mold clamping mechanism extremely high, and processing costs are reduced.

[Brief explanation of drawings]

FIG. 1 is a structural explanatory diagram of a mold according to an embodiment of the present invention. 2 to 4 are explanatory diagrams of the operation of the mold shown in FIG. 1, and FIG. 5 is an explanatory diagram of the prior art. (3): Fixed side mold plate, (6B spherical seat (spherical pair). (Crab mold plate support, (9): Template locking body. aQ = Movable side mold plate, (13): Cavity. (141 : Tapered part (second fitting part). (202 guide concave part (first fitting part)

Claims (1)

[Claims] a fixed-side template fixed to the die plate and having a tapered first fitting portion formed therein; a template support provided so as to be movable forward and backward with respect to the fixed-side template; A second fitting part is formed at the other end of the template support so as to form a pair of spherical surfaces in sliding contact and converge on the first fitting part, and this second fitting part is filled with molten resin. A mold comprising: a movable mold plate having a cavity; and a mold plate locking body attached to the mold plate support and rotatably supporting the movable mold plate.