JPH0623806A - Stack mold - Google Patents

Abstract

PURPOSE:To prevent the occurrence of resin leakage and air contamination during the opening period of mold. CONSTITUTION:A movable side extension manifold main body 61 is secured to a main manifold 46. A stationary side extension manifold 62 is secured to the nozzle 6 of an injection molding machine. The stationary side extension manifold 62 fits in the fixation hole 66 of the movable side extension manifold 61 in the mold opening and closing directions slidably at all times. A resin conduit 72 within the movable side extension manifold 61 is made opening to the inner peripheral surface of the fixation hole 66. resin conduit 69 within the stationary side extension manifold 62 Is made opening to the outer peripheral surface of the stationary side extension manifold 62. During the clamping period of mold, both the extension manifolds 61, 62 contract wholly, resulting in an intercommunication of the resin conduits 69, 72. During the opening period of mold, both the extension manifolds 61, 62 expand wholly, resulting in a mutual interruption of the resin conduits 69, 72.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stack mold used for resin molding, and more particularly to a resin passage opening / closing mechanism.

[0002]

2. Description of the Related Art Stack mold dies include a fixed mold and a movable mold that sandwich the intermediate mold and open and close with respect to the intermediate mold. Between the fixed mold and the intermediate mold and between the intermediate mold and the movable mold. Are used to mold products. The intermediate mold has a main manifold for distributing the resin supplied from the nozzle of the injection molding machine into cavities formed between the fixed mold and the intermediate mold and between the intermediate mold and the movable mold. While the intermediate plate including the main manifold opens and closes with respect to the fixed mold, in general, the position of the nozzle with respect to the fixed mold during molding is fixed,
The positional relationship between the nozzle and the main manifold changes as the mold is clamped and opened. Therefore, in a normal stack molding die, the resin passage from the nozzle to the main manifold is connected and disconnected as the mold is clamped and opened. For example, an extension manifold penetrating a fixed die is fixed to a main manifold, a nozzle of an injection molding machine is connected to the extension manifold when the die is clamped, and the nozzle is separated from the extension manifold when the die is opened. However, if the resin passage in the extension manifold is always open when the nozzle is separated from the extension manifold when the die is opened in this way, the nozzle of the extension manifold will be affected by the resin pressure in the manifold when the die is opened. Resin easily leaks from the touch part. If the resin leaks in this way, the next time the mold is clamped,
The leaked resin may be sandwiched between the mold and the nozzle, damaging the mold and the nozzle. With this,
Air easily enters the resin passage of the extension manifold. When air enters in this way, there is a risk of defective molding such as pattern formation on the molded product. In addition to the movable extension manifold fixed to the main manifold,
There is also one that fixed the fixed side extension manifold to which the nozzle of the injection molding machine is connected to the fixed mold, connected both extension manifolds at the time of mold clamping, and separated both extension manifolds when the mold was opened. The problem is similar.

Therefore, conventionally, a valve device for opening and closing the resin passage of the extension manifold has been provided, but the conventional valve device uses a hydraulic cylinder device or the like.
The structure is complicated. A shut-off nozzle is used as the nozzle of the injection molding machine.

[0004]

As described above, in the conventional stack-molding die, the extension manifold fixed to the main manifold provided in the intermediate die is usually injection-molded as the die is clamped and opened. Although the nozzle of the machine is attached and detached, if the resin passage of the extension manifold is always open, there is a problem that resin may leak or air may enter the resin passage when the mold is opened. Further, even in the case where the valve device that opens and closes the resin passage is provided, the conventional valve device uses a hydraulic cylinder device or the like, and there is a problem that the structure is complicated.

The present invention is intended to solve such a problem, and when the nozzle on the injection molding machine side is separated from the extension manifold, the resin is introduced from the resin passage of the extension manifold by the valve device having a simple structure. It is an object of the present invention to provide a hot runner die that can reliably prevent air leaks and air from entering the resin passage.

[0006]

In order to achieve the above-mentioned object, the present invention provides a fixed die, an intermediate die that opens and closes with respect to the fixed die, and a side opposite to the fixed die with respect to the intermediate die. A movable die that opens and closes; an extension manifold that has a resin passage to which a nozzle of a molding machine is connected; and a main manifold that has a runner that is provided in the intermediate die and that is connected to the extension manifold. A cavity is formed between the mold and between the intermediate mold and the movable mold, and the resin supplied from the nozzle of the molding machine is distributed to each cavity through the resin passage of the extension manifold and the runner of the main manifold. In addition, in the stack molding die that always keeps the resin in the resin passage and the runner in a molten state, A movable-side extension manifold fixed to the main manifold and a fixed-side extension manifold fixed to any of the nozzles of the fixed mold and the molding machine are provided, and both extension manifolds are opened and closed in a fixed-type and intermediate-type opening / closing direction. The resin passages in both extension manifolds are slidably always fitted, and the resin passages in both extension manifolds are the sliding surfaces of both extension manifolds. It is opened at each of the positions where it comes off.

[0007]

With the stack mold die of the present invention,
First, the fixed die and the movable die are clamped to the intermediate die to form cavities between the fixed die and the intermediate die and between the intermediate die and the movable die. With the mold clamping between the fixed mold and the intermediate mold, the movable extension manifold fixed to the intermediate mold and the fixed extension manifold fixed to the fixed mold or the nozzle of the molding machine slide in the mold opening and closing direction, Shrink as a whole. Accordingly, the resin passage in the movable-side extension manifold and the resin passage in the fixed-side extension manifold are communicated with each other because their openings to the sliding surfaces of both extension manifolds overlap each other. In this state, the resin is injected from the nozzle into the resin passage of the fixed-side extension manifold, but this resin passes from the resin passage in the fixed-side extension manifold to the runner of the main manifold through the resin passage in the movable-side extension manifold. It flows in and fills the cavity from there. After such an injection process, a pressure holding process is performed, and after the resin filled in the cavity is sufficiently cooled and solidified,
The mold is opened, and the molded product which is the resin solidified in the cavity is taken out. When the fixed mold and the intermediate mold are opened, the movable extension manifold and the fixed extension manifold slide with each other and extend as a whole, but they do not separate from each other.
At the same time, the resin passages in the movable extension manifold and the resin passages in the fixed extension manifold are blocked from each other because their openings to the sliding surfaces of the extension manifolds are displaced from each other. After the molded product is taken out, the mold is clamped again and the molding is repeated. Through such a molding cycle, the resin in the resin passage of the manifold is always kept in a molten state. However, in the mold open state, both extension manifolds are still fitted and the resin passages in both extension manifolds are blocked from each other, so that the resin does not leak from the resin passages of the extension manifolds and There is no reason for air to enter the passage. The volume of each resin passage does not change with the opening and closing of the resin passage.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the hot runner mold of the present invention will be described below with reference to the drawings. The mold of this embodiment is a stack mold as shown in FIGS. 1 and 4. First, the outline of the configuration of an injection molding machine to which this mold is attached will be described mainly based on FIG. Reference numeral 1 is a fixed platen, 2 is a tie bar, and 3 is a movable platen. The movable platen 3 is moved along the tie bar 2 by the driving of the mold clamping mechanism 4, and moves toward and away from the fixed platen 1. Further, 5 is a heating cylinder. A nozzle 6 is provided at the left end of the heating cylinder 5 in the drawing. A screw 7 (shown in FIGS. 1 and 2) is provided in the heating cylinder 5. The screw 7 is rotationally driven as well as axially driven to knead, measure, inject, and hold the resin. A hopper 8 for putting a pallet of thermoplastic resin is provided on the heating cylinder 5.

The stack mold die includes a fixed die 11, an intermediate die 12 and a movable die 13. The fixed mold 11,
The movable mold 13 is attached to the fixed platen 1 of the injection molding machine, and the movable mold 13 is attached to the movable platen 2.
The movable platen 2 is moved integrally with the movable platen 2.
On the other hand, the intermediate mold 12 is fixed to the fixed mold 11 by the guide rod 14.
It is movably supported between the mold and the movable mold 13, and is driven by the mold clamping mechanism 4 via a coupling mechanism (not shown). In this way, the intermediate die 12 and the movable die 13 respectively move in the left-right direction in the drawing, and the fixed die 11 opens and closes with respect to the intermediate die 12 on the right side in the drawing, and the movable die
Is designed to open and close on the left side. Then, as shown in FIG. 1, a plurality of product-shaped cavities 15 and 16 are formed between the fixed die 11 and the intermediate die 12 and between the intermediate die 12 and the movable die 13 during mold clamping. It is like this.

As shown in FIG. 1, the fixed mold 11 includes a fixed side mounting plate 21 mounted on the fixed side platen 1 and a receiving plate fixed on the left side of the fixed side mounting plate 21 via a spacer block 22. 23 and a template 24 fixed to the left side of the receiving plate 23. Further, the fixed side mounting plate 21
A protruding plate 25 that moves in the left-right direction relative to these is provided between the receiving plate 23 and the receiving plate 23, and the protruding plate 25 is formed between the fixed mold 11 and the intermediate mold 12. An ejection pin 26 for releasing the formed product when the mold is opened is fixed. On the other hand, the movable mold 13 includes a movable side mounting plate 31 mounted on the movable side platen 3, a receiving plate 33 fixed to the right side of the fixed side mounting plate 31 via a spacer block 32, and the receiving plate 33. And a template 34 fixed to the right side. In addition, the movable side mounting plate 31 and the receiving plate 33
A protruding plate 35 that moves in the left-right direction relative to these is provided between and, and a molded product formed between the intermediate mold 12 and the movable mold 13 is provided on the protruding plate 35. The ejection pin 36 for releasing the mold when the mold is opened is fixed. Further, the intermediate mold 12 includes a pair of receiving plates 42 and 43 fixed to each other via a spacer block 41, a mold plate 44 fixed to the right side of the right receiving plate 42, and a left side of the left receiving plate 43. And a template 45 fixed to. Then, between the mold plate 24 of the fixed mold 11 and the right mold plate 44 of the intermediate mold 12, and between the mold plate 34 of the movable mold 13 and the left mold plate 45 of the intermediate mold 12, cavity 15, 16 are to be formed. Further, between the two receiving plates 42, 43 of the intermediate mold 12,
A main manifold 46 is provided. The main manifold 46 has therein a runner 47 as a resin passage for distributing the molten thermoplastic resin supplied from the nozzle 6 of the injection molding machine to the cavities 15 and 16, and
Built-in heater 48. Also, the main manifold
Bushings 49, 50 connected to both left and right sides of the support plate 42,
It penetrates through 43 and templates 44 and 45. These bush 4
9 and 50 have gates 51 and 52 at their tips that open into the cavities 15 and 16, respectively. That is, the final branch of the runner 47 of the main manifold 46 is
The cavities 15 and 16 are communicated with each other through the insides of 9 and 50. Further, valve pins 53 and 54 for opening and closing the gates 51 and 52 are built in the bushes 49 and 50. These valve pins 53 and 54 are connected to the main manifold 46.
And is driven by cylinder devices 55 and 56 embedded in the receiving plates 42 and 43 on the side opposite to the corresponding bushes 49 and 50.

A movable extension manifold 61 fixedly connected to the main manifold 46 penetrates the fixed mold 11. On the other hand, a fixed side extension manifold 62 is fixedly connected to the nozzle 6 of the injection molding machine. That is, the nozzle 6 and the fixed-side extension manifold 62 are
For example, they are fixed to each other by a connector 63 and a bolt 64. The fixed-side extension manifold 61 is formed with a fitting hole 66 opening to the right end surface thereof, and the fixed-side extension manifold 62 is provided in the fitting hole 66 in the left-right direction in the drawing, that is, the fixed mold 11 and the middle. It is always fitted so that it can slide in the opening and closing direction of the mold 12. That is, the maximum fitting length of both extension manifolds 61, 62 is larger than the opening / closing stroke of the fixed die 11 and the intermediate die 12. The fixed extension manifold 62 has a flange portion 67 at the right end portion that abuts the right end surface of the movable extension manifold 61.
The movable extension manifold 61 has a fitting hole.
An air escape hole 68 is formed so as to escape from the inner part at the left end of 66 to the outer peripheral surface. A resin passage 69 is formed in the fixed-side extension manifold 62 in the axial direction, that is, in the left-right direction, which opens to the right end face to which the nozzle 6 of the injection molding machine is connected. The resin passages 69 are radially branched at the left end and open to the outer peripheral surface 62a of the fixed-side extension manifold 62, that is, the sliding surface with the movable-side extension manifold 63. More specifically, the outlet portion 70 of the resin passage 69 is located in a portion of the outer peripheral surface 62a of the fixed-side extension manifold 62 that is always located in the fitting hole 66 of the movable-side extension manifold body 61. An annular groove 71 is formed on the outer peripheral surface 62a of the fixed-side extension manifold 62 through the plurality of outlets 70. On the other hand, a resin passage 72 is also formed in the movable side extension manifold main body 61 in the axial direction, that is, in the left-right direction. The left end of the resin passage 72 communicates with the inlet of the runner 47 of the main manifold 46. On the other hand, the right end portion of the resin passage 72 is a branch portion that diverges to the outer peripheral side of the fitting hole 66 while branching.
It is 73. The ends of the branch portions 73 are bent inward and open to the inner peripheral surface 66a of the fitting hole 66, that is, the sliding surface with the fixed-side extension manifold 62. More specifically, the inlet portion 74 of each branch portion 73 has the inner peripheral surface 66 of the fitting hole 66.
The fixed-side extension manifold 62 at a is always located in the overlapping portion. And this fixed side extension manifold
Outlet 70 of resin passage 69 of 62 and movable side extension manifold 61
As shown in FIG. 1, the positional relationship between the resin passage 72 and the inlet portion 74 is such that when the movable extension manifolds 61 and 62 are contracted as a whole by mold clamping, the outlet portion 70 and the inlet portion 74 are mutually displaced. Overlapping, as shown in FIG. 2, the outlet portion 70 and the inlet portion 74 are set to separate from each other when extended. Thus, a valve device 75 for opening and closing the resin passages 69 and 72 that guide the molten resin supplied from the nozzle 6 of the injection molding machine to the runner 47 of the main manifold 46 is formed between the extension manifolds 61 and 62. A band heater 76 is provided on the outer peripheral surface of the extension manifold 61. Furthermore, FIG.
As shown in, a locate ring 77 is fixed to the fixed side mounting plate 21 so as to surround the extension manifolds 61 and 62.

Next, the operation of the above configuration will be described. As shown in Fig. 1, the fixed mold
The intermediate die 12 is clamped to 11 and the intermediate die 12
The movable mold 13 is clamped against the cavities between the fixed mold 11 and the intermediate mold 12 and between the intermediate mold 12 and the movable mold 13, respectively.
Form 15 and 16. The fixed side extension manifold 62 fixed to the fixed mold 11 as the fixed mold 11 and the intermediate mold 12 were clamped.
Is slidably fitted into the fitting hole 66 of the movable side extension manifold 61 fixed to the intermediate mold 12, and both extension manifolds 61,
62 shrinks as a whole. Then, in the mold clamping completed state, the inlet portion 74 of the resin passage 72 of the movable side extension manifold 61 and the annular groove 71 that penetrates the outlet portion 70 of the resin passage 69 of the fixed side extension manifold main body 62 overlap each other in the radial direction, The resin passages 69 and 72 of both extension manifolds 61 and 62 communicate with each other. When the fixed-side extension manifold 62 goes into the fitting hole 66 of the movable-side extension manifold 61, the air in the fitting hole 66 passes through the air escape hole 68 and escapes to the outside.

In the injection molding machine, the thermoplastic resin P supplied from the hopper 8 into the heating cylinder 5 is melted by heating and the rotation of the screw 7, and when the screw 7 is retracted, the tip of the inside of the heating cylinder 5 is melted. A predetermined amount is collected in the section. Then, in the mold clamping state as described above, as the screw 7 advances, the molten thermoplastic resin P is injected from the nozzle 6 into the resin passage 69 of the fixed-side extension manifold 62. This injected molten resin P
Is the outlet of the resin passage 69 in the fixed-side extension manifold 62.
Movable side extension manifold 61 from 70 through annular groove 71
Flows into the inlet portion 74 of the branch portion 73 of the resin passage 72, passes through the resin passage 72 of the movable extension manifold 61, and is guided into the runner 47 of the main manifold 46. The resin P is distributed by the runner 47, passes through the bushes 49 and 50, and flows into the cavities 15 and 16 from the gates 51 and 52. After such an injection process, a pressure holding process is performed, and each cavity 1
Pressure is applied to the resin P filled in the parts 5 and 16 from the injection molding machine side by pressing the screw 7. After the pressure-holding process is completed, the injection molding machine side starts the measuring process, and the screw 7 turns back. At the same time, after the pressure-holding step, the resin P filled in the cavities 15 and 16 is sufficiently cooled and solidified, and then, as shown in FIG.
As the mold 12 opens, the movable mold 13
Opens the mold. With the mold opening of the fixed mold 11 and the intermediate mold 12, FIG.
As shown in, the fixed-side extension manifold 62 slides out of the fitting hole 66 of the movable-side extension manifold 61 to some extent. In this way, both extension manifolds 61 and 62 extend as a whole, but do not separate from each other. In this way, when both extension manifolds 61 and 62 extend, the inlet 74 of the resin passage 72 of the movable extension manifold 61 and the fixed extension manifold 61
The annular groove 71 passing through the outlet 70 of the resin passage 69 of 62 is displaced from each other. The inlet portion 74 is closed by the outer peripheral surface 62a of the fixed-side extension manifold 62, and the outlet portion 70 is
Inner peripheral surface 66a of the fitting hole 66 of the movable side extension manifold body 61
Is blocked by. Thus, both extension manifold body
The resin passages 69 and 72 of 61 and 62 are cut off from each other. When the fixed-side extension manifold 62 projects from the fitting hole 66 of the movable-side extension manifold 61, air enters the fitting hole 66 from the outside through the air escape hole 68. Along with this, the resin P solidified in the cavities 15 and 16 as the mold is opened.
And the molded product which is away from the mold plates 44 and 45, is ejected by the ejector pins 26 and 36 and separated from the mold plates 24 and 34,
Taken out. After that, the mold is clamped again as described above, and the molding is repeated. During such a molding cycle, the resin P in the resin passages 69 and 72 of the extension manifolds 61 and 62 is always kept in a molten state by the heating of the band heater 76. The resin P in the runner 47 of the main manifold 46 is also kept in a molten state by the heating of the heater 48.
The gates 51 and 52 are opened in the injection process and the pressure holding process, but in other cases, the valve pins 53 and 52 are opened.
Blocked by 54.

According to the structure of the above-described embodiment, the fixed-side extension manifold 62 on the fixed mold 11 side and the intermediate mold 12 are opened even when the mold is open.
Side movable side extension manifold 61 is still fitted,
Moreover, the resin passages 69, 72 in both extension manifolds 61, 62
Are isolated from each other, so the manifolds 46, 61, 62
Despite the pressure of the molten resin P inside, the molten resin P in the resin passages 69 and 72 of the extension manifolds 61 and 62 does not leak. At the same time, air does not enter the resin passages 69 and 72 of the extension manifold 61. By preventing the entrainment of air in this way, it is possible to prevent defective molding and also prevent defective operation due to resin leakage. Moreover, the structure of the valve device 75 for that purpose is simple. That is, since the valve device 75 opens and closes in conjunction with mold clamping and mold opening itself, the structure can be simplified and the operation is reliable. Further, with the opening and closing of the valve device 75, the volume of the resin passage 72 on the movable side extension manifold 61 side and the volume of the resin passage 69 on the fixed side extension manifold 62 side do not change at all. That is, the amount of the molten resin P on the movable side extension manifold 61 side does not change, and the pressure thereof does not change, either.

The present invention is not limited to the above embodiment, but various modifications can be made. For example,
In the above embodiment, the fixed-side extension manifold 62 is fixed to the nozzle 6 of the injection molding machine, but the fixed-side extension manifold may be fixed to a fixed mold. Further, in the above-described embodiment, the fixed extension manifold 62 is slidably fitted to the inner peripheral side of the movable extension manifold 61. Conversely, the fixed extension manifold is slid to the outer peripheral side of the movable extension manifold. Of course, it is possible to movably fit. Further, in the above embodiment, the gates 51 and 52 are connected to the valve pins 53 and 54.
Although it is opened and closed by means of a spear, it may be opened and closed by means of a spear.

[0016]

According to the present invention, in a stack mold, a movable extension manifold fixed to the main manifold and a fixed mold are used as extension manifolds between the nozzle of the injection molding machine and the intermediate main manifold. And a fixed-side extension manifold fixed to one of the nozzles of the molding machine, and both extension manifolds are always fitted slidably in the mold opening / closing direction. Both extension manifolds are always fitted because they are sliding surfaces of the extension manifolds, and when the extension manifolds are contracted as a whole by mold clamping, they overlap each other and when they extend, they are separated from each other. In addition, especially when the mold is opened, the resin passages of both extension manifolds are blocked from each other, so that the extension manifold And that the resin passage resin leaks of, and that the air enters the resin passage can be securely prevented, thereby, possible to prevent the die malfunction or defective molding. Moreover, since the opening and closing of the resin passage is performed in conjunction with the mold clamping and the mold opening itself, the structure of the valve device can be simplified,
Further, it can be performed without changing the volume of each resin passage.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a mold clamped state showing an embodiment of a hot runner mold of the present invention.

FIG. 2 is a vertical sectional view of an extension manifold portion in the same mold opening state.

FIG. 3 is a cross-sectional view of the extension manifold of the same.

FIG. 4 is a side view of a part of the injection molding machine having the mold attached thereto.

[Explanation of symbols] 6 Nozzle 11 Fixed mold (mold body) 12 Intermediate mold (mold body) 13 Movable mold (mold body) 15 Cavity 16 Cavity 46 Main manifold 47 Runner (resin passage) 61 Movable extension manifold 62 Fixed side extension manifold 62a Outer peripheral surface (sliding surface) 66a Inner peripheral surface (sliding surface) 69 Resin passage 72 Resin passage

Claims (1)

[Claims] 1. A fixed die, an intermediate die that opens and closes the fixed die, a movable die that opens and closes on the opposite side of the intermediate die from the fixed die, and a resin passage to which a nozzle of a molding machine is connected. And a main manifold having a runner to which the extension manifold is connected and which is provided in the intermediate mold, and between the fixed mold and the intermediate mold and between the intermediate mold and the movable mold, respectively. A cavity is formed, and the resin supplied from the nozzle of the molding machine is distributed to each of the cavities through the resin passage of the extension manifold and the runner of the main manifold, and the resin in the resin passage and the runner is constantly melted. In the stack mold for keeping, as the extension manifold, a movable side extension manifold fixed to the main manifold and A fixed-side extension manifold fixed to either the fixed die or the nozzle of the molding machine, and both extension manifolds are always fitted slidably in the opening and closing directions of the fixed die and the intermediate die. The resin passage in the extension manifold is a mutual sliding surface of both extension manifolds, and is opened at a position where both extension manifolds are overlapped with each other when they are contracted as a whole by mold clamping, and when they are extended, they are separated from each other. Stack mold to be used.