JPS5894440A - Injection molding of synthetic resin and the like - Google Patents

Abstract

PURPOSE:To unnecessitate the removing process of a gate section of a molded piece and to prevent the mold piece from flaws, stains, dust, etc. by a method wherein a movable sleeve is pushed up, resin at a gate section is cut off by fixedly fitting a projected part to a recessed part to close the gate section. CONSTITUTION:The gate 38 is composed of the gate forming and choking convex section 55 provided on the lower end of the outside fixed sleeve 33 and the gate forming and choking concave section 56 provided on the upper end of the movable sleeve 40. The convex section 55 and the concave section 56 stick and fit to each other by the push-up performance of the movable sleeve 40 to cut resin at the gate section, to choke the gate section and to cure the molten resin in the cavity 54.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection molding method for synthetic resin or the like in which a gate portion is not integrally formed in a molded product.

Conventionally, in the injection molding method for synthetic resins, etc., a method has been proposed in which molten resin is injected into a cavity and then the resin is sealed and solidified. This is the txI warehouse shown in Figure 1. That is, in FIG. 1, a fixed plate 4 is fixed to a fixed side mounting plate 3 having a sprue bush 1 and a locate ring 2 attached to the center thereof. 9 is a movable plate, and a spacer block 12.

It is attached to a movable platen 17 via a movable side attachment plate 16. 5 is a fixed insert fitted into a groove provided on the fixed plate 4; 6 is a movable insert fitted loosely into a groove provided on the movable plate 9; A cavity force is formed between the 8 is a compression rod, the upper end of which is fixed to the bottom surface of the movable insert 6, and the lower end of which is fixed to the compression plate 10.
It is clamped and fixed to 11. The compression plates 10 and 11 are housed in the recess of the spacer block U, and both ends of the lower surface thereof are engaged with the shoulders of the recess. Reference numeral 13'% 14 denotes a gate shut plate, which is housed in the lower recess of the spacer block, its lower end is engaged with the movable mounting plate 16, and the upper surface and the lower surface of the compression plates 10 and 11 are connected to each other. The configuration is such that a predetermined distance of 1111 m is formed between the two.

tS is a compression rod attached to the lower surface of the gate shut plate 14, which is housed in an opening provided in the movable mounting plate 16, and is connected between the upper surface of the step provided on the outer periphery of the compression rod and the lower surface of the shoulder of the opening. A predetermined gap is formed between the two. 1
Reference numeral 8 denotes a compression piston bored in the movable platen 17 and slidably housed in the cylinder 9, with the upper end surface of the compression piston in contact with the lower surface of the compression rod 15. Both m portions of the cylinder are connected to a hydraulic pump via a hydraulic switching valve 19.

7 is a gate shut bottle, the proximal end of which is fixed to the gate shut plate 13 and 14, and the distal end thereof is connected to the middle part. The gate 22 communicates with the nozzle through the launch or spur.

In the conventional injection compression molding apparatus configured as described above, after the fixed plate 4 and the movable plate 9 are brought into close contact with each other at the parting line 231fi and the mold is clamped, molten resin is injected through the nozzle bush 1. Then, W fat is filled into the cavity 4 through the gate 4 through the sprue A and runner B, and the filling pressure presses the movable insert 6 downward and compresses the plate by 10% through the compression rod 8. 11 to the figs of the spacer block 12. In addition, the gate shut bin 7 is also pressed by the resin pressure, and the gate shut plates 13 and 14 are pressed, and its lower surface is attached to the movable side mounting plate 16 [IK crimped and compressed plate] 1 to open the bottom opening gate shut. A predetermined gap 1 is formed between the upper surface of the plate 130, and a predetermined gap 1 is further formed between the upper surface of the step part of the compression rod 150 connected to the lower surface of the gate shut plate 14 and the shoulder of the opening of the movable side mounting plate 160. form. When the cavity is completely filled with molten resin, the hydraulic switching valve 19 is switched to push up the compression piston 18. As a result, compression rond 15, gate shut plate 13
．． Gate shirt through 14) Biy? d; It is pushed up and operated, and the tip of the gate shut bottle 7 closes the gate part n. When the gate shut plate 13
When the movable insert 6 is moved, the movable insert 6 comes into contact with the compression plate 11 and is pressed via the compression rod 8 fixed to the compression plate 10.11, thereby compressing the molten N fat in the cavity 2. The operating amount of the movable insert 6 corresponds to the volumetric contraction of the resin filled into the cavity, and corresponds to the operating amount b td of the compression rod and the volumetric contraction of the resin. gate shut bin 7
It is the same as the tip MO operation amount.

However, the conventional injection molding apparatus configured as described above has the following drawbacks. In other words, (1) the gate shut bin is placed at a distance from the cavity part for reasons of mold structure such as mold strength, so the gate can be closed with a part of the gate part communicating with the cavity part. (2) Since a part of the gate part is formed integrally with the molded product, after the molding process is completed, there are There were drawbacks such as the need for processing work to remove the gate portion.

The present invention was made in order to eliminate the drawbacks of the conventional injection molding method, and is directed to a fixing member consisting of an outer fixing sleeve, an inner fixing sleeve, and a fixing piece having a convex portion on the lower end surface. , a movable member consisting of a movable sleeve with four parts provided on the upper end surface and a movable piece slidably mounted within the movable sleeve is arranged facing each other, and the fixed piece and the movable piece form a cavity, and the convex part and the concave part. After forming the molten resin and injection molding into the cavity, the movable sleeve is operated to cut the molten resin and close the gate, solidifying the resin in the cavity. It is a duck whose purpose is to provide law.

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

FIG. 8 and FIG. 3 show an embodiment of an apparatus for carrying out the injection molding method according to the present invention. In the figure, Minoru is a fixed plate and is attached to a fixed side mounting plate 31. The fixing plate n is provided with a hole, and the hole has a
The outer fixing sleeve (in which the fixing piece is inserted and fixed via the inner fixing sleeve) is fitted and fixed so that its tip protrudes.Outer fixing sleeve 33
As shown in Fig. 4 (4), (to)), a convex part for forming and closing the gate is formed on the lower end surface, and has the function of cutting the resin of the gate part. Fixed slot lj −
The outer sleeve (as shown in Figure 4 (01)
It is formed longer, and its lower end surface constitutes the upper surface of the cavity I together with the lower end surface of the fixed piece grave that is fitted and fixed thereto. 1 is a movable plate, which is supported by a receiving plate 42, and attached to the movable side mounting plate via a receiving plate 42Fi space stick. 11, and a movable side mounting plate 51 is attached to the movable platen S. A gate shut plate 44, 45 is placed in the upper part of the space formed by the receiving plate, the spacer block, and the movable side mounting plate, and a compression plate 49, 50 is placed in the lower part. A hole is provided in the movable plate 3 and the receiving plate C so as to communicate with each other. Figure 5 (4
), as shown in (B), a movable sleeve having the same diameter as the outer fixed sleeve is provided with a concave portion corresponding to the convex portion provided on the lower end surface of the outer fixed sleeve on the upper surface G1. ,
It is slidably inserted through the gate, and its lower end is clamped and fixed with the gate shut plate. The gate shut plate (K) is connected to a gate shut piston (K) operated by a hydraulic switching valve 47, and when the piston is inactive, the lower surface of the receiving plate (a) and the gate shut plate (K) 44 ( A predetermined distance of 11t between the upper surface of D
Form a. There is a movable piece 4 inside the movable sleeve.
1 is movably fitted, the upper surface g14 corresponds to the lower end surface of the fixed piece I, forming the lower surface of the cavity 8,
Its lower end is connected to a compression rod C
The lower end portion of is clamped and fixed to the compression plate 49 (material).

Reference numeral 52 denotes a protruding rod that is in contact with the lower surface of the compression plate, and is slidably arranged in a hole bored in the movable side mounting plate j and the movable platen group, and its lower end is connected to a protruding rod operation part (not shown). Connected - Next, the operation of the device configured in this way will be explained. First, by a mold clamping operation, the fixed plate thickness and the movable plate 1 are brought into close contact with each other, and the parting line is closed. At this time, the tip of the inner fixing sleeve that holds the fixed piece, which is assembled so that its tip protrudes inside the outer fixing sleeve supported by the fixed plate, can slide into the movable plate 1. The movable piece 41 is inserted into the supported movable sleeve 1 and is slidably fitted into the movable sleeve. A cavity is formed between the distal end of the movable piece 41 and the protrusion 1 on the outer fixed sleeve. S55 and the recess of the movable sleeve ψ do not fit tightly together, forming a passage for the molten W fat into the cavity. As shown in FIG. 2, the interval fl[a is maintained.

In this state H, when the molten resin is injected through the nozzle, the injection pressure causes the resin to flow into the sprue winch, runner 1, and
Due to the loose fit between the convex part 5 and the concave part provided on the outer fixed sleeve part and the movable sleeve part, the cavity 8 is passed through the gate formed between the tip and bottom part thereof.
is filled with.

The state is shown in Fig. 6. When the cavity 8 is filled with the filler, as shown in Fig. 3, the hydraulic switching lever 47 is operated to push up the gate shut piston casting, and as shown in Fig. 3. Push up the movable sleeve 4 through the connected gate shut plate.
When the outer fixed sleeve is pushed up, the convex part of the outer fixed sleeve and the four parts of the movable sleeve fit tightly together, cutting the resin present in the gate iris, closing the gate, and opening the cavity ( The resin filled inside is completely confined and solidified in the cavity 8. Then, when the resin in the cavity is cooled and solidified, the mold is opened and the molded product is taken out.

In addition, at this time, by extruding the compression plate (material) by the keyaki company, the movable piece 41 is pushed up via the compression rod 1, and the molded product is discharged from the cavity. Next, the hydraulic switching valve 47 is operated to return the gate shut piston u to the initial state a, and the - cycle is completed.

FIG. 8 shows another example of the means for pushing up the gate shut plate 6.
A cam d is provided on the lower surface of the gate, and the cam is driven by a hydraulic device, pneumatic device, electromagnetic device, or other mechanical pressurizing device 4, and a return spring is provided for returning the gate shut plate 44, 45. Nails are installed between the strike plate and the play.

Further, the shape of the cavity is not limited to that shown in Fig. 2, etc., but can be applied to various shapes as shown in Fig. 9 CA), (B), and (C1l). Although the fixing sleeve and the fixing piece are shown as being formed separately, they can operate in the same way even if they are formed integrally.

As described above in detail based on the embodiments, the present invention provides an internally movable fixing member consisting of an outer fixing sleeve having a convex portion at the lower end, an inner fixing sleeve, and a fixing piece attached to a fixing plate. The fixed piece and the movable piece form a cavity with a movable sleeve and a movable member that is movably fitted on the movable plate and are arranged opposite to each other. A gate is formed by each part and a concave part, and by pushing up the movable sleeve, the convex part and the four parts are closely fitted, cutting the resin at the gate part, closing the gate, and solidifying the molten resin in the cavity. 2. Unlike the conventional method, which solidifies the resin with the gate part communicating with the cavity, the gate part does not communicate with the cavity part during molding, and the mass balance is improved. Good 9: Dimensional accuracy is stable. In addition, there is no need to remove the gate part as in conventional cases where the gate part is integrally molded into the molded product, and therefore, there is no need to remove scratches, dirt, or dust that may occur due to the removal process. It is possible to obtain effects such as being able to prevent

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway plan view of a conventional injection molding device;
The figure is a partially cutaway plan view showing a state during injection of an apparatus for carrying out an embodiment of the injection molding method according to the present invention;
The figure is a partially cutaway plan view showing the state of the device shown in FIG. 2 when the gate is closed; FIGS. 4(A) and CB) are partially cutaway plan views and front views of the outer fixation sleeve; Figure (0) is a partially cutaway plan view of the inner fixation sleeve, ta5 view (A), CB
) is a partially cutaway plan view and front view of the movable sleeve, Figure 6 is an enlarged view of the main part of Figure 2, Figure 7 is an enlarged view of the main part of Figure 's3, and Figure 8 is an enlarged view of the main part of Figure 2. 9(A), (B), and (0) are partially cutaway plan views of the modified example of the device shown in FIG.
FIG. 6 is a diagram showing a modified example of the shape of the cavity. In the diagram, 3! ke fixed mounting plate, n ke fixing plate, n is outer fixing sleeve, 34 is inner fixing sleeve, 35 is fixing piece,
36 is a sprue, 2 is a runner, 38 is a gate, 39 is a movable plate, 4o is a movable sleeve, 41 is a movable piece, 42 is a receiving plate, 43 is a compression rod, 4% 45 is a gate seal plate, 46 is a gate shut Piston, 47 hydraulic switching valves, 48 is a spacer plate, 49, ■ is a compression plate, 51 is a movable side mounting plate, ♀ is a protruding rod, S is a movable platen, (ke cavity, 5 is a convex part for gate formation and closing, 4 parts for forming and closing the gate, 4 parts for gate shut cam, and 4 parts for gate formation and closing.
Reference numeral 7 indicates a gate shut pressurizing device, and reference numeral 57 indicates a gate shut plate return spring. Patent applicant: Olympus Optical Industry Co., Ltd. Figure 3 Tomi Figure 4 (A) (B) 5 (C) Utsugi Figure 5 (A) (B) Figure 6
Chapter 7 Figure 9 (A) (B) (C)
No. 87 47' Place-

Claims (1)

[Claims] A movable member having a mutually movable gate forming liquid gap section and a cavity forming section is arranged opposite to a fixed member having a gate forming/closing section and a cavity forming section. A gate is formed by the forming/closing part, and a cavity is formed by both cavity-forming parts. After injecting and filling the molten resin into the cavity through the gate, the movable gate forming/closing aS is operated to press the gate part. An injection molding method characterized by cutting 1111 of the cavity, closing the gate, and then solidifying the molten resin in the cavity.