JPH08127049A - Resin molding machine - Google Patents

Abstract

PURPOSE: To provide an excellent resin molding machine capable of constituting a sprue runnerless system at low cost in an extremely simple structure and capable of smoothly pushing back the unnecessary molded article in a sprue part to a resin injection part still more even when the molded article is not in a solidified state. CONSTITUTION: In a resin molding machine sending the molten resin 4 into a cavity 3 from a resin injection part 1 through a sprue runner part 2 such as a sprue part 2A or a runner part 2B to mold the same, the resin push-back member 5 allowed to protrude into the sprue part 2A of the sprue runner part 2 to be moved into the sprue part 2A toward the resin injection part 1 to push back the unnecessary molded article 6 in a solidified or sem-solidified state within the sprue part 2A into the resin injection part l by the heat of the resin injection part 1 is arranged to the sprue part 2A in a freely movable manner. A capsule cylindrical element 50 has a bottomed cup shape of which the leading end part on the side of the resin injection part l is opened and is set to the shape arranged to the sprue part 2A in an inscribed state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding method and a resin molding machine in which molten resin is fed into a cavity from a resin injection portion through a runner portion such as a sprue portion or a runner portion and resin molding is performed. is there.

[0002]

2. Description of the Related Art In conventional resin molding, an injection nozzle (resin injection portion) is provided at the tip of a cylinder, and, for example, from this injection nozzle, from a sprue portion, a gate portion, a runner portion, etc. The molten resin in the cylinder is injected into the cavity from the injection nozzle through the runner, and the inside of the cavity is cooled to a predetermined temperature to solidify or cure the resin in the cavity to form a molded product. Molding is performed, the mold is released, the cavity is opened, and the molded product is released from the cavity and discharged.

In this case, in the conventional method, at the same time as the molding of the molded product is discharged, an unnecessary molded product called a runner (sprue runner) which is molded in the runner is discharged.
Conventionally, since this runner is a waste of material, it has been devised to crush the runner, mix it again with the resin virgin material, and reuse it in order not to waste the material.

However, such discharge of the runners, distribution of the runners and molded articles, and the reuse (recycling) system of the runners are very troublesome.
Therefore, a hot runner system has been developed in which the runner is constantly heated during forming, and the runner is not forcibly cooled and solidified and the runner is not discharged.

However, since the runnerless method using the hot runner system is a method of providing a heating device in the vicinity of the cavity that should be cooled originally, a heat insulating structure must be provided between the cavity and the heating device. It is an expensive system, not a general-purpose system.

Therefore, in general, the idea that the runner is discharged and the runner is reused without waste has been the mainstream.

Therefore, in view of such a current situation, the applicant has considered
Although the idea was completely changed from the conventional one, we developed an excellent resin molding method and resin molding machine that does not discharge the runner with an extremely simple means without relying only on heating means such as a hot runner system ( Japanese Patent Application No. 5-84732.
The present invention is further prototyped.
It is an object of the present invention to provide a resin molding machine capable of favorably pushing back undesired moldings in the sprue part, which has been improved through repeated studies.

[0008]

The gist of the present invention will be described with reference to the accompanying drawings.

[0009] In the resin molding machine for feeding the molten resin 4 into the cavity 3 from the resin injecting section 1 through the runner section 2 such as the sprue section 2A and the runner section 2B, the sprue section of the runner section 2 is used. When the sprue portion 2A is moved toward the resin injecting portion 1 by protruding into the 2A, the unnecessary molded product 6 in the solidified state or the semi-solidified state in the sprue portion 2A is formed.
The resin push-back body 5 for pushing back the resin injection section 1 is movably arranged in the sprue section 2A, and the capsule cylinder 50 enclosing the resin 4 in the sprue section 2A is moved by the resin push-back body 5 in the resin injection section 1A. Is disposed in the sprue portion 2A in an inscribed state so that the molten resin 4 injected from the resin injection portion 1 is provided at the tip end portion of the capsule cylinder 50 on the resin injection portion 1 side. It has an introduction opening 51 that is guided into the capsule cylinder 50, and the bottom 52 on the opposite side is formed in a closed state. To the runner 2B on the side closer to the bottom 52 in this closed state, the molten resin in the capsule cylinder 50 is formed. Gate opening where 4 is guided
The present invention relates to a resin molding machine in which 53 is formed.

Further, the capsule cylinder 50 is attached to the resin injection portion 1
The resin molding machine according to claim 1, wherein the resin molding machine has a bottomed cup shape with an open front end portion, and is set to be inscribed in the sprue portion 2A.

Further, the bottom surface position of the capsule cylinder 50 in which the bottom surface of the bottom portion 52 of the capsule cylinder 50 is formed in a raised state and the molten resin 4 flows in is the gate opening formed on the side portion of the capsule cylinder 50. The molten resin 4 is set so as to be substantially flush with 51, and the molten resin 4 does not stay at the bottom portion 52 of the capsule cylinder 50. 5. The present invention relates to a resin molding machine.

[0012]

Function: After the molten resin 4 is fed from the resin injecting section 1 into the cavity 3 through the runner section 2, the resin push-back body 5 projects into the runner section 2 (sprue section 2A) and further the resin injecting section Move toward 1 and runner part 2 (sprue part 2A)
The unnecessary molding 6 inside is pushed back to the resin injection part 1. The unnecessary molded product 6 pushed back is pushed back into the resin injection part 1 in a molten state by the heat of the resin injection part 1.

At this time, the sprue portion 2A is arranged so that the capsule cylinder 50 enclosing the resin in the sprue portion 2A can be moved into the resin injecting portion 1 by the resin pushing back member 5.
The resin push-back body 5 is arranged in the inscribed state inside.
When is pushed back and moved, the resin push-back body 5 pushes the capsule cylinder 50 into the resin injecting section 1, and the unnecessary molded product 6 in the sprue section is pushed back to the resin injecting section 1 while being housed in the capsule cylinder 50. . Therefore, the unnecessary molded product 6 (resin) in the capsule cylinder 50 is pushed back together with the capsule cylinder 50.

When the resin 4 is injected again from the resin injection section 1, the capsule cylinder 50 may be moved back to a predetermined position along with the return movement of the resin push-back body 5. Even when the capsule cylinder 50 is pushed out, the capsule cylinder 50 is pushed back into the sprue portion 2A by the injection pressure from the resin injection part 1, and the capsule cylinder 50 is again inserted from the introduction opening 51 at the tip.
The resin 4 is injected into the inside of the capsule 50, introduced into the runner portion 2B from the gate opening 53 on the side of the capsule cylinder 50, and injected into the cavity 3.

[0015]

EXAMPLE This example is a sprueless method developed by the applicant as described above (Japanese Patent Application Nos. 5-84732 and 6).
No. -4103, etc.), but in order to make it easier to understand the improvements of the present invention, the basic configuration and basic operation before the improvement will be described in detail with reference to FIGS. 1 to 15.

This embodiment is based on the following method.

In the resin molding method in which the molten resin 4 is fed from the resin injecting section 1 through the runner section 2 consisting of the sprue section 2A into the cavity 3 through the gate section 9 (or the runner section 2B), After the molten resin 4 is fed into the cavity 3 by the movement of the screw 13 and the molded product 8 in the cavity 3 is cured, the rod-shaped resin push-back member 5 is projected into the sprue portion 2A and further into the resin injection portion 1. The unnecessary molded product 6 in the semi-solidified state is pushed back to the resin injection part 1 to move the unnecessary molded product 6 to the resin injection part 1
It is pushed back into the resin injecting section 1 in a molten state by the heat of. At this time, the resin push-back body 5 is moved by the movement of the resin push-back body 5.
The gate closing portion 5A on the side of the side closes the gate portion 9 into the cavity 3, and the injection closing portion 5B at the moving front end portion of the resin push-back body 5 closes the injection inlet of the resin injection portion 1.

Therefore, the resin molding machine in this embodiment has a concrete construction as shown in FIGS.

In the illustrated first embodiment based on this basic technique, it can be said that only the so-called sprue portion 2A is provided, and the cavities 3 are arranged on the left and right sides of the sprue portion 2A, and the sprue portion 2A and the cavity 3 are formed. It may be considered that the runner part 2 connecting the above is omitted, and that the gate part 9 and the runner part 2B are slightly present between the sprue part 2A and the cavity 3.

Further, the mold 7 is released, the cavity 3 is opened, and the molded product 8 in the cavity 3 is ejected by an ejector rod.
A push-back ejector device 11 that moves by the drive source of the ejector device 10 that pushes out and discharges at 10 A is provided.
On the moving plate 11A of the push-back ejector device 11, a rod-shaped resin push-back body 5 is provided so as to project toward the sprue portion 2A.

Therefore, the resin push-back member 5 is constructed such that the movable tip portion closes the tip portion of the sprue portion 2A before moving, and after the molded article 8 in the cavity 3 is hardened, the rod rod The resin push-back body 5 is pushed into the sprue portion 2A by moving the moving plate 11A of the push-back ejector device 11 forward, and further moved toward the resin injecting portion 1 to remove the semi-solidified unnecessary molding 6 from the resin. Push back to the injection part 1. After the unnecessary molded product 6 in the sprue 2A is pushed back, after moving, the peripheral surface of the resin push-back body 5 serves as the gate closing portion 5A, and the gate closing portion 5A connects the left and right gate portions 9 which are the injection introducing portions in the cavity 3. The injection closing portion 5B that is closed and formed at the movable tip portion is configured to go straight toward the resin injection portion 1 and close the resin injection portion 1.

In this way, the unnecessary molded product 6 in the runner part 2 is pushed back by the movement of the resin push-back body 5, and the unnecessary molded product 6 is pushed back to the resin injection part 1 in a molten state by the heat of the resin injection part 1. The resin injection part 1 is closed. The injection blocking part 5B at the tip of the resin push-back body 5 may be inserted deep into the injection injection port of the resin injection part 1.

Thereafter, the mold 7 is released and the cavity 3 is removed.
Ejected, ejector rod 10 of ejector device 10
A is projected and moved by the movement of the ejector moving plate 10B, and the molded product 8 attached to the cavity 3 is extruded and discharged.

Further, in this embodiment, there is no tapered (small diameter) injection nozzle portion as in the prior art, and the runner portion 2 (sprue portion 2A) is formed with the diameter substantially the same as the diameter of the cylinder 12. The runner portion 2 and the resin injection portion 1 cannot be clearly distinguished from each other. Therefore, the sprue portion 2A has a diameter larger than that of the conventional sprue portion.

That is, the resin injection portion 1 is closed by the injection closing portion 5B of the resin push-back member 5 during molding as in this embodiment, and the runner portion 2 is cooled and hardened, semi-molten or melted. Since it can be molded, it does not require a conventional injection nozzle having a small diameter. Therefore, there is no injection resistance by the nozzle portion as in the conventional case, and the low-pressure injection of the molten resin 4 is possible, so that the warpage and deformation of the molded product 8 can be reduced, and the dispersion of goodness and badness of the molded product 8 for each molding shot. The effect is also reduced.

That is, the injection blocking portion 5B of the resin push-back body 5
Since the resin injection part 1 is closed by the above, even if the resin injection part 1 and the runner part 2 (sprue part 2A) have a large diameter, the resin leakage can be reliably prevented, and the unnecessary molded product 6 at the sprue part 2A has a large diameter. Since there is no hindrance to the molding of the molded product 8 even in the semi-molten state, it is possible to design the structure without the small-diameter injection nozzle portion that exhibits the excellent effect as described above.

The present invention may be applied to a structure in which the runner part 2 is composed of only the sprue part 2A as shown in FIG. 4, or a structure having a runner part 2B as shown in FIG. The sprue runner is not molded and discharged, but a structure in which a slight runner is discharged as the unnecessary molded product 6 may be used.

Further, the tip end portion of the resin push-back body 5 is divided to form a tip division portion 5S (shuttle rod portion), and the resin push-back body 5 is moved to make the tip division portion 5S (shuttle rod portion) the resin injection portion. 1, the unnecessary molded product 6 in the sprue portion 2A is pushed back into the resin injecting portion 1, and when the resin pushing back body 5 moves back (retracts), the tip cutting portion 5
S (shuttle rod part) does not move and remains inserted in the resin injecting part 1, and the tip cutting part 5S left behind is left.
The (shuttle rod portion) may be configured to be movable back in the sprue portion 2A by the injection pressure at the next resin injection.

FIGS. 6 to 12 show a second embodiment based on the basic method. In this embodiment, the following method is used.

The gate portion 9 and the runner portion 2 are provided in the cavity 3 on the left and right of the resin injection portion 1 through the sprue portion 2A.
In the resin molding method in which the molten resin 4 is fed through B to perform resin molding, the molten resin 4 is fed into the cavity 3 by the movement of the screw 13 and the molded product 8 in the cavity 3 is cured, and then the resin push-back body 5 is moved to push back the unnecessary molding 6 in the cured state to the resin injecting section 1, and the unnecessary molding 6 is pushed back into the resin injecting section 1 in a molten state by the heat in the resin injecting section 1. At this time, the gate closing portion 5A on the side of the resin pushing back body 5 closes the gate portion 9 into the cavity 3 by the movement of the resin pushing back body 5, and the injection closing portion 5B at the moving tip portion of the resin pushing back body 5 is closed. It is inserted into the resin injection part 1 and the resin injection part 1 is closed.

Therefore, the resin molding machine according to the present embodiment is specifically constructed as shown in FIGS.

In the illustrated second embodiment, it can be said that the runner portion 2 is almost composed of only the so-called sprue portion 2A, and the cavities 3 are arranged on the left and right sides of the sprue portion 2A, and the sprue portion 2A and the cavity. The runner part 2 that connects 3 and 3 has a structure in which a runner part 2B having a slight length is provided via a gate part 9.

The mold 7 is released, the cavity 3 is opened, and the molded product 8 in the cavity 3 is ejected by the ejector rod.
A push-back ejector device 11 that moves by the drive source of the ejector device 10 that pushes out and discharges at 10 A is provided.
On the moving plate 11A of the push-back ejector device 11, a rod-shaped resin push-back body 5 is provided so as to project toward the sprue portion 2A.

Therefore, the resin push-back body 5 is constructed so that the movable tip portion closes the tip portion of the sprue portion 2A before moving, and after the molded product 8 in the cavity 3 hardens, the rod-shaped rod 5 The resin push-back body 5 is pushed into the sprue portion 2A by moving the moving plate 11A of the push-back ejector device 11 forward, and further moved toward the resin injecting portion 1 to remove the semi-solidified unnecessary molding 6 from the resin. Push back to the injection part 1. After the unnecessary molded product 6 in the sprue 2A is pushed back, after moving, the peripheral surface of the resin push-back body 5 serves as the gate closing portion 5A, and the gate closing portion 5A connects the left and right gate portions 9 which are the injection introducing portions in the cavity 3. The injection closing portion 5B that is closed and formed at the movable tip portion is configured to go straight toward the resin injection portion 1 and close the resin injection portion 1.

The movement control section for moving the resin push-back body 5 comprises the push-back ejector device 11 and a drive source for controlling and driving the ejector device 11.

Further, in this embodiment, since the unnecessary molded product 6 is pushed back until the moving front end (injection blocking part) 5B of the resin push-back body 5 is inserted into the resin injection part 1, the unnecessary molded product 6 is surely made into resin. In addition to being able to push back into the injection portion 1, the moving tip portion (injection closing portion) 5B of the resin push-back body 5 is inserted into the resin injection portion 1 and heated each time the resin push-back body 5 is pushed back. The resin does not stick to the tip of the resin injection part 1 and hinder the movement of the resin push-back body 5.

Next, the improvements of the second embodiment will be described.

In the second embodiment, after the unnecessary molded product 6 is pushed back into the resin injection part 1 by the movement of the resin push-back body 5,
In the injection-free state until the injection of the molten resin 4 for the next molding, the plug mechanism 14 is operated to make the resin injection part 1 injectable. That is, the resin injection part 1 is provided with the plug mechanism 14 capable of switching between the injection possible state and the injection unnecessary state, and the unnecessary molded product 6 is pushed back into the resin injection part 1 by the movement of the resin push-back body 5, and the next molding For this reason, a switching mechanism 15 is provided to switch the plug mechanism 14 to the injection disabled state until injection of the molten resin 4 to make the injection disabled.
In particular, in this embodiment, the resin push-back body 5 is constituted by a rod rod slidably arranged in the sprue portion 2A which is the runner portion 2, and the tip of the resin push-back body 5 is inside the resin injection portion 1. A movement control unit for driving and controlling the push-back ejector device 11 so that the resin (sprue runner) in the sprue portion 2A, which is the unnecessary molded product 6, is pushed back into the resin injection unit 1 by moving the resin until it is inserted into the resin injection unit 1. .

As shown in FIGS. 9 to 12, the stopper mechanism 14 of this embodiment is provided with a stopper rod 14A in the resin injection passage 1A near the tip of the nozzle of the resin injection portion 1, and the stopper rod 14A is provided in this stopper rod 14A. 9
A communication hole that allows the resin injection path 1A to be in communication when rotated by 0 degrees
14B is formed. Further, the stopper rod 14A of the stopper mechanism 14 is rotated to close the resin injection passage 1A so that the resin injection portion 1 cannot be injected, and the stopper rod 14A is rotated 90 degrees to connect the communication hole 14B to the resin injection passage 1A. A switching mechanism 15 is provided which communicates with the switch and operates to switch to an injection ready state. This switching mechanism 1
5 is provided with a link mechanism 15A on the stopper rod 14A.
A movable rod 15B for operating the link mechanism 15A is connected to 5A, and a drive source for moving the movable rod 15B back and forth is provided. By controlling this drive source, the movable rod 15B and the link rod 15A via the link mechanism 15A. The plug mechanism 14 is switched and operated by rotating.

Therefore, after the resin push-back body 5 is pushed back and moved to push the unnecessary molded product 6 back into the resin injecting section 1, the movable side of the mold 7 is opened and released. When the body 5 retracts from the inside of the resin injecting section 1, the switching mechanism 15 is controlled in synchronism with this to switch and operate the stopper mechanism 14 to surely make the resin injecting section 1 in the injectable state,
When the mold 7 is closed and the molten resin 4 is injected again in the next molding, the switching mechanism 15 operates the stopper mechanism 14 to enable the injection.

Reference numeral 16 in the figure is a heat resistant Teflon packing.

Therefore, since the present embodiment is constructed as described above, it is an excellent resin molding method and resin molding machine which can construct a runnerless system (sprueless system) at an extremely simple structure and at low cost. Resin injection part 1
Therefore, it becomes an excellent resin molding method and a resin molding machine capable of surely preventing the so-called beating phenomenon in which the resin 4 is spontaneously injected when unnecessary.

13 to 15 show a third embodiment.

In this embodiment, the mold 7 is constructed so that the cavity 3 can be opened and closed by splitting it from the parting line 17 by a mold clamping mechanism, and a part of the cavity 3 is provided on the movable side of the mold 7. The forming block body 18 constituting the mold is arranged so that it can be released and moved, and the forming block body 18 is retracted by the movement drive mechanism 19 to open the cavity 3 from the parting line 17 and form the molded product 8 in the cavity 3. When the molded product 8 is released from the mold after molding, the mold clamping mechanism is kept as it is, and the mold block body 18 is moved in the mold releasing condition. The ejector device 10 ejects and ejects.

When performing the next molding again, the molding block 18 is moved back to close the cavity 3.

The cavity 3 is opened by operating the mold clamping mechanism at the time of maintenance of the cavity 3 and the like, and when the cavity 3 is opened and closed in a normal molding shot, only the block body 18 is slid (movably opened and closed). By doing.

Therefore, the mold opening / closing of the cavity 3 is sufficient if the molding block 18 is moved by a small distance so that the molded product 8 can be discharged. Therefore, it is not necessary to operate a large mold clamping mechanism for each molding shot, and the deviation due to this operation is unlikely to occur in the cavity 3. Therefore, the durability of the mold 7 and the mold clamping mechanism is improved, and the running cost is reduced. Markedly reduced.

This embodiment is applied to such a so-called open / close mold system developed by the applicant.

Further, in this embodiment, the sprue portion 2A is further provided on the fixed side of the mold 7, but the so-called unit system is formed in which the sprue portion 2A is formed by mounting the sprue block body 20.

The sprue block body 20 has a sprue portion 2A formed therein, and projecting ridge portions 21 are formed on the outer peripheral surface thereof at a predetermined interval to mount the sprue block body 20 on the fixed side of the mold 7. In doing so, the air insulating layer 22 as the heat insulating portion 22 that insulates the cavity 3 is formed around the sprue portion 2A by the space between the protruding ridge portions 21.

In the present invention, the molten resin 4 between the sprue portions 2A is
However, unlike the conventional method, it is not necessary to cool and solidify the molten resin 4 in the sprue portion 2A because the resin is pushed back into the resin injection portion 1 instead of being molded and discharged.

When pushing back, the resin injection part 1
Since the material is pushed back while being melted by the heat of, the molten material can be pushed back instantly or smoothly rather than being solidified.

Therefore, in this embodiment, the cavity 3 and the sprue portion 2A, which need to be cooled and solidified, are thermally insulated as much as possible so that the molten resin 4 in the sprue portion 2A is hardened to be solidified. .

In this embodiment, the sprue block 2 has a unit system for the heat insulating effect, and the sprue block body 20 is used.
The air heat insulating layer 22 is formed as the heat insulating portion 22 so as to surround the sprue portion 2A by simply providing the protruding strip portion 21 on the outer peripheral surface of the above. This is a method that is extremely excellent in mass productivity and does not cost much.

Based on this idea, the movable-side resin push-back body 5, the resin push-back body 5 moving block that communicates with the sprue portion 2A and moves the resin push-back body 5 forward and backward, and the drive mechanism for the resin push-back body 5 are provided. The sprueless mechanism according to the present invention can be easily installed in an existing conventional mold by simply making each unit into a unit and detachably mounting this unit together with the sprue block body 20 in the mold 7. . Furthermore, FIG. 13 and FIG. 1 show an injection molding machine configured based on the method of the third embodiment.
This will be specifically described with reference to FIG.

In the figure, reference numeral 23 is a fixed platen, 24 is a tie bar, and 25 is a movable platen. The movable platen 25 is constituted by a mold clamping device such as a toggle so that the mold clamping mechanism can be freely opened and closed.

The movable screw 13 is attached to the fixed platen 23 side.
A resin injection part 1 for injecting and injecting the molten resin 4 is provided.

The molten resin 4 extruded from the resin injection part 1 is filled in the cavities 3 at two places via the sprue part 2A having a large diameter and the runner part 2B branched to the left and right.

In this embodiment, a molding block body 18 forming a part of the cavity 3 is provided on the movable platen 25 side of the cavity 3 via the parting line 17, and the movable platen 25 of the molding block body 18 is provided. On the side (rear side), a molding block body 18 is provided so that it can be released and moved by forming a space in which it can be released and moved.

A block body movement drive mechanism 19 for releasing the molding block body 18 (moving it forward and backward) is provided behind the molding block body 18.

The sprue portion 2 is provided on the fixed side of the mold 7.
Although A is provided, the sprue portion 2A is formed by mounting the sprue block body 20 in a unit system.

The sprue block body 20 has a sprue portion 2A formed therein, and projecting ridge portions 21 are formed on the outer peripheral surface thereof at predetermined intervals, so that the sprue block body 20 is mounted on the fixed side of the mold 7. At this time, the air insulating layer 22 is formed as the heat insulating portion 22 by the gap between the protruding ridges 21.

Next, the discharge ejector device in this embodiment
10, a block body movement drive mechanism 19 commonly used as a push-back ejector device 11, and a discharge ejector device 10
The driving means for the ejector rod 10A and the resin push-back body 5 will be described. In this embodiment, the molded block body 18
Molding block 18 is moved to the rear of the mold (moving forward and backward)
The opening / closing rod 26 is connected, the ejector rod 10A and the resin push-back body 5 are coaxially arranged, and movement control is performed by a block body movement drive mechanism 19 configured by a hydraulic cylinder device capable of performing hydraulic pressure switching control by the same cylinder. There is.

In the figure, reference numeral 27 is a moving plate having the opening / closing rod 26 protruding, 10B is a moving plate having the ejector rod 10A protruding, and 11B is a moving plate having the resin push-back member 5 protruding. Connecting rods 30, 31, 32 are respectively projected to the rear of 10B, 11B,
31 and 32 are arranged in each of the three hydraulic chambers 33, 34 and 35 of the hydraulic cylinder device 19A of the block body movement drive mechanism 19.

Therefore, this embodiment operates as follows, and molding is performed from the mold clamping state of FIG. 13 to the state of releasing the molded product 6 shown in FIG.

First, when oil is injected into the third hydraulic chamber 35,
The resin push-back member 5 advances through the connecting rod 32 and the moving plate 11B to push the molten resin 4 in the sprue portion 2A back to the resin injection portion 1. This realizes the sprueless molding method described above.

Next, when oil is injected into the first hydraulic chamber 33, the opening / closing rod 26 is pulled through the connecting rod 30 and the moving plate 27, and the molding block body 18 is moved backward by a predetermined small distance. Then, the cavity 3 has a parting line 17
Open from.

Finally, oil is injected into the second hydraulic chamber 34 to eject the ejector rod through the connecting rod 31 and the moving plate 10B.
10A is pushed forward, and the molded product 8 in the cavity 3 of the molding block body 18 is projected, dropped and discharged.

After discharging the molded product 8 as shown in FIG. 14 in this way, the above-described reverse operation is performed to return the molding block body 18 to its original position and move it to close the cavity 3. Mold again.

As described above, in normal molding, the mold clamping mechanism is not operated at all, and while the mold clamping state is maintained, the molding block body 18 is opened and closed by a minimum distance, and the molding is discharged. Will be realized.

In the present invention, when the tip of the resin push-back member 5 is pushed back into the resin injection part 1 and inserted, the inner diameter of the resin injection part 1 is set so that the molten resin 4 surrounds the tip. It is desirable to design the resin injection part 1 to be slightly larger than the outer diameter. With this design, the resin (unnecessary molded product 6) in the sprue portion 2A pushed back by the resin push-back body 5 is surrounded by the molten resin 4 and easily melts instantly. Therefore, the unnecessary molded product 6 in the sprue part 2A is hard to solidify due to the heat insulating part 22, and even when solidified, the unnecessary molded product 6 is pushed back by the resin push-back member 5 so that the unnecessary molded product 6 is melted in the resin injection part 1. Since it is surrounded by 4 and melts quickly, a high cycle of molding shot can be achieved. Further, a sudden load on the heater provided in the resin injection part 1 can be suppressed.

The above is the resin molding machine which realizes the sprueless method developed by the applicant. In the present invention, the sprueless method shown in the above-mentioned embodiment is further improved. The improvement which is the gist of the present invention will be described with reference to FIGS. 16, 17, and 18.

In this embodiment, the capsule cylinder 50 enclosing the resin 4 in the sprue portion 2A is replaced by the resin push-back member 5.
Is disposed in the sprue portion 2A so as to be movable into the resin injecting portion 1 by means of the resin injecting portion 1 at the resin injection portion 1 side tip end. The molten resin 4 has an introduction opening 51 through which the capsule cylinder 50 is introduced, and the bottom 52 on the opposite side is formed in a closed state,
A gate opening 53 through which the molten resin 4 in the capsule cylinder 50 is guided to the runner portion 2B is formed on the side of the bottom portion 52 in this closed state.

Further, in this embodiment, the first and second aspects are set.
Belonging to the invention described above, the capsule cylinder 50 is a cup-shaped cup having an elongated bottom with an open end on the resin injection part 1 side, and is slidably disposed in the sprue part 2A in an inscribed state. The shape is set to be.

In the above-described embodiment based on the basic method described so far, which is shown in FIGS. 1 to 15 for explaining the basic construction, the resin push-back member 5 is simply pushed directly into the sprue portion 2A, and the resin push-back member 5 is used directly. The unnecessary molded product 6 in the sprue part 2A is pushed back to the resin injection part 1.

However, as a result of repeated experiments, if the unnecessary molded product 6 in the sprue portion 2A is completely cooled and solidified, the resin push-back member 5 relatively smoothly pushes the resin back into the resin injection portion 1. However, it was found that the unnecessary molded product 6 cannot be pushed back well unless the degree of solidification in the semi-solidified state is high.

As described above, since the diameter of the sprue portion 2A is large in this machine, the unnecessary molded product 6 is not completely solidified when the molded product 8 of the cavity 3 is cooled and solidified. When pushed back in this semi-solidified state, the outside of the unnecessary molded product 6 is likely to be melted due to friction with the inner surface of the sprue portion 2A and the like, so that it is relatively difficult to restore smoothly. If the unnecessary molded product 6 is pushed back in the molten state, the resin push-back body 5 and the sprue portion 2A
It was found that the resin push-back member 5 could not be pushed back satisfactorily due to the molten resin entering into the clearance for sliding with the inner peripheral surface and solidifying, and burrs and the like were also generated.

Therefore, the closer to the solidified state, the better the performance. Therefore, it is necessary to push back and move the resin push-back body 5 at a time interval when the unnecessary molded article 6 is sufficiently cooled and solidified. Therefore, it takes time for the molding cycle. I found a problem that would end up.

That is, as described above, it is preferable that the diameter of the sprue portion 2A is large. Therefore, the larger the diameter of the sprue portion 2A, the longer the solidification time is, and the longer the molding cycle is.

Therefore, the present invention is improved as described above in order to solve such a problem.

Therefore, in this embodiment, the resin push-back member 5 can be moved satisfactorily without any trouble and the above-mentioned sprueless method can be realized, and the capsule cylinder 50 enclosing the resin in the sprue portion 2A can push back the resin push-back member. Since the body 5 is disposed in the sprue portion 2A in an inscribed state so as to be movable into the resin injecting portion 1, when the resin pushing back body 5 is pushed back and movable, the resin pushing back body 5 causes the capsule cylinder body 50 to move. Are extruded into the resin injecting section 1, and the unnecessary molded product 6 in the sprue section is pushed back into the resin injecting section 1 while being housed in the capsule cylinder 50. Therefore, the unnecessary molded product 6 (resin) in the capsule cylinder 50 is
Therefore, even if the unnecessary molding 6 of the capsule cylinder 50 is insufficiently cooled and is in a semi-solidified or molten state, the molten resin 4 has been a problem in the above-described embodiment. That is, the resin push-back body 5 can move favorably without flowing out to the point, that is, the clearance, and burr does not occur. Therefore, the molding cycle is short and mass productivity is improved without waiting for the unnecessary molded product 6 to solidify.

In this embodiment, the capsule cylinder 50 has a bottomed cup shape, but the resin cylinder 4 does not leak from the introduction opening 51 at the tip into the gap between the capsule cylinder 50 and the sprue portion 2A. It suffices that the material is injected into the inside of the chamber 50 and then injected into the sprue portion 2A and the cavity 3 through the gate opening 53, and the shape material and the like can be set appropriately.

Further, in this embodiment, which belongs to the invention described in claim 3, the bottom surface of the capsule cylinder 50 in which the bottom surface of the bottom portion 52 of the capsule cylinder 50 is formed in a raised state and the molten resin 4 flows in However, the molten resin 4 is set so as to be substantially flush with the gate opening 51 formed on the side portion of the capsule cylinder 50 so that the molten resin 4 does not stay at the bottom 52 of the capsule cylinder 50. .

Therefore, the gate opening 53 is connected to the runner portion 2B.
Even if it is formed slightly closer to the tip side than the bottom according to the position of
The bottom surface of 52 is raised to the position where the gate opening 53 is formed, and no recessed recess is formed at the bottom.

Therefore, no retention resin is injected and discharged to the bottom portion 52 of the capsule cylinder 50 (it is difficult to be melted and discharged even in the resin injection portion 1), so that molding failure is less likely to occur and burned retention is still difficult. Since the resin does not flow out, a good molded product can be obtained without causing stains in the resin molding with transparency or coloring.

In this embodiment, the bottom 52 is thickened to raise the bottom. However, the bottom 52 is formed with a concave outer surface so that the resin push-back body 5 fits into the bottom of the capsule cylinder 50. Is also good.

Further, the raised bottom surface is made to slightly project so that the outflow from the gate opening 53 is favorably promoted and the resin is further prevented from being retained.

Further, the resin push-back body 5 and the capsule cylindrical body 50
In order that the capsule cylinder 50 can move smoothly, the capsule cylinder 50 may be formed in a tapered tube shape whose diameter becomes smaller toward the resin push-back body 5 side.

In the present invention, as in the present embodiment shown in FIG. 17, only the resin push-back body 5 is opened when the mold is opened in a state where the capsule cylinder 50 is pushed back into the resin injection part 1 by the return movement of the resin push-back body 5. Since the capsule cylinder 50 is configured to return and move, the capsule cylinder 50 is left as it is in the resin injecting portion 1, and the capsule cylinder 50 is automatically returned and movable by injection pressure during injection. The capsule cylinder 50 performs the same function as the structure having the tip dividing portion 5S (shuttle rod portion) described above, and has the plug effect of preventing the resin leakage (hanging) phenomenon of the resin injection portion 1. Will also be fulfilled.

Further, the following resin molding machine can be realized by applying the concept of moving the capsule cylinder 50 of the present invention by the resin push-back body 5.

That is, the resin push-back body 5 serving as the capsule pushing body is moved from the resin injection part 1 to the capsule cylinder 50.
It is configured so that the movement of the molten resin 4 can be controlled during the injection operation of injecting the molten resin 4 into the cavity 3 through the cavity, and the mold is pushed from the gate opening 53 of the capsule cylinder 50 that is moved by the movement of the resin push-back body 5. The sprue portion 2A is removed or the gate opening portion of the sprue portion 2A is designed so that the molten resin 4 can be injected into the tee 3.

As a result, the capsule cylinder 50 functions as a runner part that moves forward and backward from the inside of the resin injecting part 1, spruelessness is realized as in the present invention, and the position of the gate opening which is the injection port can be easily adjusted. The resin molding machine can be movably controlled, and a resin molding machine with high availability can be realized.

Therefore, it is possible to escape from the conventional resin flow mechanism in which the resin flowing from the gate port can be fed to the cavity tip direction only by the pressure of the resin flowing from the rear. Capsule barrel
In the concept of controlling the movement of 50, the gate part moves while ejecting toward the injection part, so it is possible to shorten the distance from the tip of the cavity to the gate part (depending on the placement of the cavity part), Molding of ultra-thin materials, which has been impossible with conventional technology, is possible with extremely low injection pressure, and by shortening the flow distance of the resin, it is possible to fill while the flow resistance due to cooling of the flow resin is extremely low. Since it is completed, there is no need to raise the mold temperature, and it can be designed for a resin molding machine that enables a high cycle that has never been seen before.

Incidentally, as shown in FIG. 19, for example, by making the capsule cylinder 50 rectangular and making the shape of this capsule cylinder 50 the same as the shape of the tip end port of the resin injection part 1, the position of the gate opening 53 can be adjusted. It is desirable that the capsule cylinder body 50 is always maintained in a constant direction without being displaced due to forward and backward movements.

[0095]

As described above, the present invention is an excellent resin molding machine capable of constructing a runnerless system (sprue runnerless system) at a low cost with an extremely simple construction.

Moreover, the present invention has the introduction opening and the gate opening as described above, and the capsule cylinder for enclosing the resin in the sprue portion can be moved into the resin injecting portion by the resin pushing back member. Since it is installed in the sprue part in an inscribed state, the resin push-back body can be moved without any problems, and the sprueless method described above can be realized.
This resin push-back body pushes the capsule cylinder into the resin injection part, and the unnecessary molding product in the sprue part is pushed back to the resin injection part while being stored in the capsule cylinder, so even if the unnecessary molding product of the capsule cylinder is cooled. Even if it is insufficient and is in a semi-solidified or molten state, this molten resin has been a problem in the above-described embodiment, that is, the resin does not flow out into the clearance, and the resin push-back body can move satisfactorily, and the burrs Does not occur. Therefore, it becomes an excellent resin molding machine in which the molding cycle is short and mass productivity is improved without waiting for the unnecessary molded product to solidify.

Further, the bottom surface of the capsule cylinder is formed so that the bottom surface of the bottom of the capsule cylinder is raised, and the position of the bottom surface of the capsule cylinder into which the molten resin flows is substantially flush with the gate opening formed on the side of the capsule cylinder. By setting so that the molten resin does not stay at the bottom of the capsule cylinder,
Since non-retained resin that is not ejected and discharged to the bottom is not formed,
With an excellent resin molding machine that does not easily cause molding defects and does not cause burned non-resisting resin to flow out, so that it does not produce stains in resin molding that imparts transparency or color and can obtain good molded products. Become.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a sprueless molding method and a molding machine as a basic example of the present invention when a resin is injected.

FIG. 2 is a schematic sectional view of a sprueless molding method and a molding machine as a basic example of the present invention when a resin push-back body is movable after completion of resin injection.

FIG. 3 is a schematic cross-sectional view of a sprueless molding method and a molding machine as a basic example of the present invention at the time of discharging a molded product after mold release.

FIG. 4 is an enlarged explanatory cross-sectional view of a main part of a sprueless molding method and a molding machine as a basic example of the present invention at the time of resin injection.

FIG. 5 is an enlarged explanatory cross-sectional view of a main part at the time of resin injection of another example of the sprueless molding method and the molding machine as the basic example of the present invention.

FIG. 6 is a schematic sectional view of a sprueless molding method and a second embodiment of a molding machine as a basic example of the present invention at the time of resin injection.

FIG. 7 is a schematic sectional view of a sprueless molding method and a second embodiment of a molding machine, which are basic examples of the present invention, when a resin push-back body is movable after completion of resin injection.

FIG. 8 is a schematic cross-sectional view of a sprueless molding method and a molding machine according to a second embodiment of the present invention, at the time of discharging a molded product.

FIG. 9 is an enlarged explanatory cross-sectional view of a main portion of the second embodiment of the sprueless molding method and the molding machine, which is a basic example of the present invention, when the resin push-back body is movable after completion of resin injection.

FIG. 10 is an enlarged explanatory cross-sectional view of a main part of a sprueless molding method and a second embodiment of a molding machine, which are basic examples of the present invention, at the time of discharging a molded product.

FIG. 11 is an exploded perspective view of a sprueless molding method as a basic example of the present invention and a stopper mechanism of a second embodiment of a molding machine.

FIG. 12 is an enlarged plan view showing a sprueless molding method as a basic example of the present invention and a plug mechanism and a switching mechanism of a second embodiment of a molding machine.

FIG. 13 is a schematic sectional view of a sprueless molding method and a molding machine as a basic example of the present invention at the time of resin injection.

FIG. 14 is a schematic sectional view of a sprueless molding method and a molding machine as a basic example of the present invention when a molded product is discharged.

FIG. 15 is an enlarged perspective view of a sprue block body forming a sprue portion of a sprueless molding method and a third embodiment of a molding machine as a basic example of the present invention.

FIG. 16 is a schematic sectional view showing the structure of the embodiment of the present invention when resin injection is completed.

FIG. 17 is a schematic cross-sectional view of the configuration of the embodiment of the present invention when the resin push-back body is being pushed back and movable after the completion of resin injection.

FIG. 18 is an explanatory perspective view of a capsule cylinder showing an embodiment of the present invention.

FIG. 19 is an explanatory perspective view of another example showing a case where the capsule cylinder of the present invention has a rectangular shape.

[Explanation of symbols]

 1 Resin Injection Section 2 Runner Section 2A Sprue Section 2B Runner Section 3 Cavity 4 Resin 5 Resin Pushback Body 6 Unnecessary Molded Material 50 Capsule Cylindrical Body 51 Introduction Opening 52 Bottom 53 Gate Opening

Claims (3)

[Claims] 1. In a resin molding machine for injecting molten resin into a cavity from a resin injecting portion through a runner portion such as a sprue portion or a runner portion to perform resin molding, the resin is injected by projecting into the sprue portion of the runner portion. When the inside of the sprue part is moved toward the part, the resin push-back body that pushes back the unnecessary molded product in the sprue part in the solidified or semi-solidified state into the resin injection part is movably arranged in the sprue part. The capsule cylinder that wraps around the inside of the sprue part is inscribed so that it can be moved into the resin injection part by the resin push-back body. The molten resin injected from the has an introduction opening that is introduced into the capsule cylinder,
A resin molding machine characterized in that a bottom portion on the opposite side is formed in a closed state, and a gate opening portion for guiding the molten resin in the capsule cylinder to a runner portion is formed on a side portion near the bottom portion in the closed state. 2. The capsule cylinder has a bottomed cup shape in which a tip end on the resin injection portion side is open, and is set to be inscribed in the sprue portion. 1. The resin molding machine according to 1. 3. A bottom surface position of the capsule cylinder in which the bottom surface of the bottom portion of the capsule cylinder is formed in a raised state so that the molten resin flows in is substantially flush with the gate opening formed in the side portion of the capsule cylinder. The resin molding machine according to any one of claims 1 and 2, wherein the molten resin is set so that molten resin does not stay at the bottom of the capsule cylinder.