JPS6067126A - Injection molding apparatus - Google Patents

Abstract

PURPOSE:To obtain a molded article having no hollows inside and no sinkmarks on the surface, by injecting resin into a mold cavity formed between a fixed half of a mold and a movable half thereof, and then by reducing the volume of the cavity before the resin is set. CONSTITUTION:After a fixed half 1 of a mold and a movable half 2 thereof are made to contact with each other under a prescribed pressure, melted thermoplastic resin is injected into a mold cavity 3 of a movable block 10 through a sprue 4, runners 5 and 6 and a gate 7. Before the resin in cooled down to be set, the block 10 is moved, by a block driving means B, from a position indicated by a solid line to a position indicated by a dot-and-dash line A, so as to reduce the volume of the cavity 3. The resin is thereby compressed and then cooled down to be set, and thereafter the movable half 2 is separated apart to open the mold. Next, a pressure rod 20 is moved in the direction opposite to the direction of an arrow (a) to make a pressure plate 18 integral therewith being abutted against an ejector plate 15 so as to move it by pressure, and thus a molded article sticking on the wall surface of the mold cavity 3 is separated by an ejector pin 16.

Description

Detailed Description of the Invention Technical Field The present invention relates to a method of injecting molten thermoplastic or thermosetting resin into mold cavities of a fixed mold and a movable mold, solidifying the resin, and then transferring the resin from the fixed mold to the movable mold. Take out the molded product at a distance and use the 1-output hV excitation.

Conventional technology Molten resin is injected into the mold holes of a fixed mold and a movable mold.
In addition, an injection molding apparatus is known that solidifies the resin using a fixed mold and a movable mold without changing the volume of the mold cavity.

However, this injection molding apparatus has the disadvantage that small cavities may be formed inside the molded product, and dents may be formed on the surface of the molded product.

Purpose An object of the present invention is to provide an injection molding device that can effectively prevent the formation of cavities inside a molded product and also effectively prevent the formation of depressions on the surface of a molded product. .

Configuration Next, the configuration of the present invention will be explained based on illustrated embodiments.

In FIG. 1, reference numeral 1 indicates a stationary mold that is fixed at a predetermined position. A movable mold 2 is arranged so as to be movable in the direction of contacting and separating from the fixed mold 1.

A mold cavity 3 is formed in a portion where the fixed metal IJil and the movable mold 2 face each other. As shown in FIG. 2, the fixed mold IVc is formed with a glue 4 and a runner 5 for guiding the heated and melted thermoplastic resin injected from a resin injection means (not shown) to the mold cavity 3. has been done. The above movable mold 2. A runner 6 and a gate 7 communicating with the runner 5 are formed therein.

The fixed mold IK has a hole 8 communicating with the mold cavity 3 and a large hole 9 communicating with the hole 8.

A movable block 10 is movably arranged in the holes 8 and 9 and the mold cavity 3Vc. One surface of this movable block 1o constitutes one wall surface of the mold cavity 3.

A plurality of guide shafts 11 are arranged in the hole 9 of the identification mold 1, and both ends of these guide shafts 11 are fixed to the wall of the hole 9. The guide shaft 11 has a port 12.
is movably mounted. A movable block 10 is fixed to this plate 12. Above play) 1
A suppressing spring 13 is arranged between the guide shaft 2 and the wall of the hole 9 in a state where it is wound around the guide shaft 11. These springs 13 urge the plate 12 toward the movable mold 2.

A hole 14 is formed in the movable mold 2.

This hole 14 is connected to the large diameter part located on the fixed mold l side.
and a small part formed to have a step. An ejector plate 15 is arranged in the large diameter portion of the hole 14 of the movable mold 2. This ejector plate 1
An ejector bin 16 is fixed to 5. Fixed metal 8 of the movable mold 2 above! ! The front part near l has mold hole 3 and hole 14.
A small hole 17 is formed to communicate with each other. The tip of the ejector pin 16 is disposed in this small hole 17.

An ejector plate 15 is provided in the hole 14 of the movable mold 2.
A suppression plate 18 is movably arranged on the opposite side of the fixed mold l. A hole 19 is formed in the rear part of the movable mold 2 to communicate the hole 14 with the outside. A press rod 20 is inserted into the hole 19 of the movable mold 2 .

A pressing plate 18 is fixed to the tip of the pressing rod 20. This pressing rod 20 is reciprocated in the direction of arrow a and in the opposite direction by a driving means (not shown) using hydraulic pressure or the like.

A plurality of suppression pins 21 are fixed to the suppression plate 18 . Above ejector plate 15° movable mold 2
and the fixed mold l has f'L small holes 22, 23, respectively.
24 is formed. These small holes 22, 23, 24
The suppression bottle 21 is arranged so as to be inserted through it. A grate 12 is pressed against the tips of these press bottles 21 by the pressing force of a spring 13.

The pressing rod 20 is moved forward in the direction away from the fixed mold 1, that is, in the direction of arrow a, and the suppressing plate 1 is integrated with the pressing rod 20.
When the plate 12 and the press bottle 21 move forward, the spring 13 presses the plate 12 and moves the plate 12 forward.
The movable block 10 integrated with the mold cavity 3 is moved back and forth from the position shown by the solid line in FIG. 1 to the position shown by the dashed line A, and the volume of the mold cavity 3 is reduced. Next, the pressing rod 20 is moved back in the direction of the arrow a, and the counter 18 and the pressing bottle 21 are moved back, so the plate 12 and the movable block 10 are moved back against the pressing force of the spring 13, so that the mold hole is removed. The volume of 3 is expanded.

The above-mentioned suppression rod 20, drive means for reciprocating the same, press plate 18, suppression pin 21. The plate 12, the guide shaft 11, and the spring 13 constitute block driving means B for moving the movable block 10.

From the state where the movable mold 2 is separated from the fixed mold IK, the movable mold 2 is brought closer to the fixed mold 1 by mold clamping means (not shown), and a predetermined pressure is applied as shown in FIG. Apply pressure. In this case, one wall surface 7 of the mold cavity 3 of the movable block 10 is located at a position 9 indicated by a solid line,
In this state, thermoplastic resin heated and melted by the resin injection means is injected into the mold cavity 3 through the sprue 4, runners 5, 6, and gate 7. Before this resin is cooled and solidified by the fixed mold 1 and the movable mold 2, str +
7- While the resin is in liquid state, the moving block 10 or the block driving means B moves the resin from the position shown by the solid line to the dashed dot line A.
The mold cavity 3 is moved forward to the position indicated by , the volume of the mold cavity 3 is reduced, and the resin is compressed.

Pipes through which water passes are arranged in the fixed mold 1 and the movable mold 2, and water is supplied from the outside to these pipes, passes through the pipes, and is discharged to the outside. The water flowing through these pipes F1'3 cools the resin injected into the mold cavity 3.
The heat applied to the fixed mold 1 and the movable mold 2 during this process is released to the outside to maintain the fixed mold 1 and the movable mold 2 at a predetermined temperature.

After the resin injected into the mold cavity 3Vc is cooled and solidified by the fixed mold 1 and the movable mold 2, the movable mold 2 is separated from the fixed mold 1 by a mold opening means (not shown).

When the movable mold 2 is separated from the fixed mold l, the molded product is moved together with the movable mold 2 while being attached to the wall surface of the mold cavity 3 of the movable mold 2.

Next, after the movable mold 2 is separated from the fixed mold l by a predetermined distance, the press rod 2o is moved in the direction opposite to the direction of the arrow a, and the suppression plate 1-18 integrated therewith is moved to move the ejector plate. 15 and suppress it. This ejector plate 15 is moved ζ,
An ejector pin 16 integrated therewith is moved to press the molded product adhering to the wall surface of the mold cavity 3 and separate it from the movable mold 2.

After the molded product is removed from the movable mold 2 by a distance of N1 by the ejector vinyl 21, the suppression rod 20 is moved in the direction of arrow a, and the suppression grating 18 integrated therewith is also moved to return to the standby position. When the movable mold 2 is brought into contact with the fixed mold 1, the ejector plate 15 and the ejector bin 16 are moved to the standby position shown in FIG. It returns to the position where it abuts the stepped portion of No.14.

Another embodiment of the invention is shown in FIG. 3 and will now be described.

In the embodiment shown in FIG.
It is made by arranging. The block driving means B for moving the movable block 10 includes a plurality of guide shafts 26 whose both ends are fixed to the wall of the hole 14 of the movable mold 2, and is movably attached to these guide shafts 26. A plate 27 to which the movable block IO is fixed, a suppressing spring 28 which is wound around the guide shaft 26 and biases the plate 27 in the rearward direction of the movable mold 2, and a spring 28 arranged in the small diameter part of the hole 14. a pressing plate 18 that is fixed to the pressing plate 181C and whose tip end is in contact with the grating 27KBE; and a suppressing bottle 29 that is arranged to be inserted through the hole 19 at the rear of the movable mold 2 and whose tip end is in contact with the grating 27KBE. It consists of a pressing rod 20 to which a pressing rod 1/-) 1.8 is fixed, and a driving means (not shown) for reciprocating the pressing rod 2o in the direction indicated by the arrow and in the opposite direction. In this case, a plurality of guide holes 3o are formed in the front part of the movable mold 2, a plurality of kite bins 31 are fixed to the plate 27, and the tips of these guide pins 31 are formed in the guide holes. 30&C has been inserted.

The movable block 10 shown in FIG. 3 and the block drive means B for moving it also serve as ejector means for pressing the molded product attached to the movable mold 2 and separating it from the movable mold 2.

The structure of the embodiment shown in FIG. 3 other than the above-mentioned structure is the same as the embodiment shown in FIGS. 1 and 2.

Another embodiment of the invention is shown in FIG. 4, which will now be described.

In the embodiment shown in FIG. 4, a hole 25 communicating with the mold cavity 3 is formed in the movable mold 2, and a movable block 10 is inserted into the hole 25.
It is made by arranging. The block driving means B for moving the movable block 10 includes a press rod 20 arranged to be inserted into the hole 19 at the rear of the movable mold 2, and a press rod 20 that moves the press rod 20 in the direction indicated by the arrow and in the opposite direction. A reciprocating drive means (not shown), a plate 32 fixed to the distal end of the suppression rod 20, a rear end fixed to the plate 32, and a movable block IO fixed to the distal end. and a connecting rod 33.

An ejector plate 15 is arranged in the large diameter portion of the hole 14 of the movable mold 2. This ejector play) 15
A hole 34 is formed in the center of the hole 34, and a connecting rod 33 is inserted through this hole 34. The ejector plate 15vc has an ejector bin 16 fixed thereto and a guide bin 35 fixed thereto. The above movable block l
OK, the tip of the small tap pin 16 is placed in the small hole 36, and the tip of the guide bin 35 is placed in the guide hole 37. A pressing spring 38 is arranged between the plate 32 and the ejector plate 15. These springs 38 press the ejector plate 15 toward the stationary mold 1 . When the fixed mold 1 and the movable mold 2 are in pressure contact, the guide bin 35 is stopped by the fixed mold 1, and the ejector plate 15 and ejector pin 16 remain stationary at the position shown in FIG. .

When the movable mold 2 is separated from the fixed mold 1 after the resin in the mold cavity 3 is cooled and solidified by the fixed mold 1 and the movable mold 2, the stopping force on the guide bin 35 is released. Then, the ejector plate 15 and ejector bin 16 move toward the fixed mold 1 due to the pressing force of the spring 38, and press the molded product attached to the wall surface of the mold cavity 3, thereby releasing the molded product from the movable mold 2. Separate.

The structure of the embodiment shown in FIG. 4 other than the above-mentioned structure is the same as that of the embodiment shown in FIGS. 1 and 2.

FIG. 5 shows the main part of another embodiment of the present invention, which will be explained next.

In the embodiment shown in FIG. 5, a hole 8 communicating with a mold cavity 3 is formed in a fixed mold 1, and a movable block 10 is disposed in this hole 8. The block driving means B for moving the movable block 10 includes (2) a plurality of guide shafts 11 whose both ends are fixed to the wall of the hole 9 of the foot mold l, and a block drive means B that is movable to these guide shafts 11; a grate 12 to which the movable block 10 is fixed while being attached;
Between this plate 12 and the wall of the hole 9 there is a guide l1IIl
A suppressing spring 3 is wound around the IVc and biases the plate 12 in the direction away from the movable mold 2.
9, a rotating shaft 40 disposed near the plate 120 in the hole 9, a cam 41 fixed to the rotating shaft 40 and having a plate 12 pressed against it by the pressing force of a spring 39, and a rotating shaft 40. and a driving means (not shown) for rotating the .

When the rotating shaft 40 is rotated in the direction of arrow C, the cam 41 integrated therewith is rotated, and the plate 12 and movable block 10 are reciprocated in the direction of arrow a and the opposite direction.

The structure of the embodiment shown in FIG. 5 other than the above-mentioned structure is the same as that of the embodiment shown in FIGS. 1 and 2.

FIG. 6 shows the main part of another embodiment of the present invention, which will be explained next.

In the embodiment shown in FIG. 6, a hole 8 communicating with a mold cavity 3 is formed in a fixed mold 1, and a movable block 10 is arranged in this hole. The above movable plate, ,, 7 l 1
1 +ff1ItI+(訃subro,, /7 f!ji
lit -E=9 B A plurality of guide shafts 11 whose both ends are fixed to the wall of the hole 9 of the fixed foot ff1l, and a movable block lO which is movably attached to these guide shafts 11. Fixed Great 12 and
A guide shaft 111C is provided between this plate 12 and the wall of the hole 9.
A suppressing spring 13 that is wound around and urges the plate 12 toward the movable mold 2, an annular member 42 fixed to the plate 12, and a hole 43 at the rear of the fixed mold 1. a wedge-shaped member 44 that is inserted into the hole 9 from above and whose tip is inserted into the hole 42a of the annular member 42;
It comprises a driving means (not shown) for reciprocating the wedge-shaped member 44 in the direction of arrow d and in the opposite direction.

When the gravel member 44 is moved forward in the direction of the arrow d, the spring 13 presses the plate 12 and is moved toward the movable mold 2, so that the movable block 10 is moved forward in the direction of the arrow a. Next, when the wedge-shaped member 44 is moved back in the direction opposite to the direction of the arrow d, the wedge-shaped member 44 moves in the direction away from the annular member 42' and the movable mold 2 against the pressing force of the spring 13. The block 10 is moved back in the direction opposite to the direction of arrow a.

The structure of the embodiment shown in FIG. 6 other than the above-mentioned structure is the same as that of the embodiment shown in FIGS. 1 and 2.

Note that the present invention can also be applied to the case where a molded product is produced using a thermosetting resin.

Effects The injection molding apparatus of the present invention can effectively prevent the formation of cavities inside the molded product, and can also effectively prevent the formation of depressions on the surface of the molded product.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view showing an injection molding apparatus of the present invention;
FIG. 2 is an enlarged sectional view of the main parts of the injection molding apparatus, FIGS. 3 and 4 are partially cutaway plan views showing other embodiments of the present invention, and FIGS. The figure is a partially cutaway plan view showing the main part of another embodiment of the present invention. 1...Fixed mold, 2...Movable mold, 3...Mold hole,
lO...Movable block, B...Putsuk driving means

Claims (1)

[Claims] A fixed mold that is fixed at a predetermined position, a movable mold that is movable in contact with and away from the fixed mold, and a mold formed by these fixed molds and the movable mold. A hole formed in a fixed mold or a movable mold so as to communicate with the hole, a movable block which is movably arranged in the hole and the mold cavity and whose one side forms one wall of the mold cavity, and this movable block. and a block driving means for moving the movable block, and after injecting resin into the mold cavity, the movable block is moved before the resin is solidified to reduce the volume of the mold cavity.