JPH09314616A - Molded article ejecting device and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ejector pin marks from appearing on the surface of a molded article by a method wherein the ejecting force of the molded article is damped by means of an ejecting force damping part provided at least on an ejector pin, on an ejecting plate, on which the ejector pin is mounted, or on an ejector rod. SOLUTION: An ejector pin 17 is planted to an ejecting plate 21 comprising a first and a second ejecting plates 15 and 16. At the end on an ejector rod 22 side of the first ejecting plate 15, a metal coiled spring 18, at the end of which an oil damper 19 is connected, is provided. The metal coiled spring 18 and the oil damper constitute an ejecting force damping part 19a. The ejector rod 22 pushes the ejecting plate 21 through the ejecting force damping part 19c passing through the hole part 23 of a movable mounting plate 11. The ejecting plate 21 moves together with the ejector pin 17 so as to release a molded article from a movable core part 14. Thus, by the simple structure that the ejecting force damping part 19a is fixed to the ejecting plate 21, the deformation of a molded article is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded product ejecting device used for discharging a molded product when a synthetic resin is injection-molded, and in particular, an ejector pin bites into the molded product when the molded product is ejected. The present invention relates to a molded product projecting device and a molded product molded by this device, which can prevent deformation such as whitening of the traces.

[0002]

2. Description of the Related Art A conventional technique for discharging a molded product without causing deformation such as whitening is disclosed in JP-A-6-254916. This device is composed of a protruding member having a large molded product pressing surface movably provided on a mold and a molded product pressing surface fitted axially movably in the axial direction of the protruding member. It is composed of a small protruding pin (ejector pin) and a protruding drive device for moving these two members.

A method of ejecting a molded product in an injection molding machine using this device is such that a protruding member having a large molded product pressing surface provided movably in a mold and an axial direction of the protruding member coincide with the moving direction of the protruding member. The projecting pin, which has a small pressing surface of the molded product and is movably inserted in the axial direction, is moved relative to the mold in synchronization with each other by the projecting drive device to pre-project the molded product in the mold. After that, the ejection pin is ejected and moved in the axial direction by the driving device to perform the actual ejection of the molded product.

In addition to the above, Japanese Unexamined Patent Publication (Kokai) No. 6-114897 discloses a method of discharging a molded product without causing deformation such as whitening. This method controls either one or both of protrusion pressure control and speed control.

That is, according to this method, from the start of ejection to the start of release of the molded product, the adhesive force between the molded product and the mold is loosened at a low speed by either the ejection pressure control or the speed control. Make the first protrusion. Then, after the mold release is started, the ejector pin performs the second protrusion at high speed until reaching the drop position of the molded product, and the ejector pin performs the third protrusion accompanied by minute vibration after reaching the drop position of the molded product. It is a thing.

In addition to these methods, a method of discharging a molded product by compressed air (air) without using an ejector pin is also commonly used.

[0007]

The conventional nuclear technology described above has the following problems. JP 6
The technology disclosed in Japanese Patent No. 254916 has a much more complicated structure than that of the conventional mold, which makes not only the manufacturing troublesome but also the control of the drive becomes difficult.

The technique disclosed in Japanese Unexamined Patent Publication No. 6-114897 also has the same problem as described above because the structure is far more complicated than the conventional molding machine. Further, even in the case of the protrusion by air, it is troublesome to manufacture a mold and a device for the protrusion by air, which not only raises the manufacturing cost but also causes a noise due to the air.

The present invention has been made in consideration of such conventional problems. Even in a molding machine that does not have the function of controlling the ejecting pressure and the speed, the ejecting force of the ejector rod is directly applied to the molded product. Therefore, it is possible to obtain a molded product that is free from deformation, such as whitening, because the ejector pin bites into the molded product when ejecting the molded product, leaving a trace on the surface, even though it is simple. An object of the present invention is to provide a molded product ejecting device. Another object of the present invention is to provide a molded product obtained by this device.

[0010]

A molded product ejecting apparatus of the present invention is provided with at least one of an ejector pin provided in a molding die, a protruding plate to which the ejector pin is attached, or an ejector rod constituting an injection molding machine. ,
It is characterized in that a protruding force buffering portion for buffering a protruding force when the molded product is protruded is provided.

An elastic body, a viscous body, or a combination thereof can be used as the above-mentioned projecting force buffering section. In the case of an elastic body, the ejection force can be adjusted by changing its elastic modulus, and in the case of a viscous body, the ejection force can be adjusted by changing its viscosity. When the elastic body and the viscous body are combined, the ejection force can be adjusted by changing either the elastic modulus or the viscosity.

In the present invention, a spring made of metal or synthetic resin can be used as the elastic body. As the shape of this spring, a coil spring, a leaf spring or the like can be selected. As the elastic body other than the spring, rubber such as synthetic rubber and natural rubber can be used.

As the viscous body, a damper such as an air damper or an oil damper can be used, and further, a damper that operates both oil and air as a viscous fluid can be used.

In the present invention, the above elastic body and viscous body may be arranged in parallel or in series. In these combinations, one of them may be used in plural, and the plural may be arranged in parallel or in series.

The molded product of the present invention is molded by a molding die or an injection molding machine or a molding die and an injection molding machine equipped with the molding product ejecting device according to the first aspect.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 shows a part of an injection molding machine equipped with Embodiment 1 of the present invention, and 20 is a movable side die plate as a component of the injection molding machine. An ejector rod 22 as a component of the injection molding machine is provided inside the movable die plate 20. The ejector rod 22 is reciprocally driven in the opening and closing direction of the mold, and the advancing drive thereof ejects the molded product.

The movable mold 10 is a movable mold mounting plate 11,
The spacer block 12, the movable die receiving plate 13, and the movable die core portion 14 are provided, and the first protrusion plate 15 and the first protruding plate 15 and the first protrusion plate 15 are provided inside the space formed by the movable die mounting plate 11, the spacer block 12, and the movable die receiving plate 13. 2 protruding plate 16
Is arranged. Reference numeral 17 denotes a plurality of ejector pins 17 which are constituent parts of the movable die 10 and also serve as projecting members for the molded product, and only one ejector pin 17 is shown in the illustrated example.

The movable mounting plate 11 is fastened to the movable die plate 20 with bolts or the like (not shown). The first projecting plate 15 and the second projecting plate 16 form a projecting plate 21 by being fastened with bolts or the like (not shown). The ejector pin 17 is embedded in the protruding plate 21. The entire projecting plate 21 is slidably supported by a return pin (not shown) and moves in the opening / closing direction of the mold.

A metal coil spring 18 is attached to the end of the first projecting plate 15 on the ejector pin 22 side, and an oil damper 19 is connected to the end of the metal coil spring 18 in the axial direction of the spring 19. Are connected together. The metal coil spring 18 and the oil damper 19 form a protruding force buffering portion 19a. In this case, by changing one or both of the elastic modulus of the metal coil spring 18 and the oil viscosity of the oil damper 19, the protruding plate 2 is protruded from the protruding force buffering portion 19a.
You can adjust the power to convey to 1.

The ejector rod 22 of the molding machine pushes the projecting plate 21 through a projecting force buffering part 19a consisting of an oil damper 19 and a metal coil spring 18 through a hole 23 opened in the movable die mounting plate 11. be able to.

In the above embodiment, the movable type mounting plate 1
1, the spacer block 12, the movable die receiving plate 13, and the movable die core portion 14 are components of the molding die, and the movable die plate 20 is a component of the injection molding machine. The ejector rod 22 is a component of the injection molding machine and a component of the molded product ejecting device. Furthermore, metal coil spring 18 and oil damper 1
9, the projecting plate 21, and the ejector pin 17 are components of the molding die and also of the molding product ejecting device.

Next, the operation of ejecting an injection-molded product by this apparatus will be described. After the injection process is performed by the injection molding machine, the movable mold 10 is separated from the fixed mold (not shown) of the mold by the mold opening operation of the injection molding machine, and moves to the position set at the start of molding. At this time, the molded product is in close contact with the movable core portion 14.

At the time when the mold opening operation of the movable mold 10 is completed, the ejector rod 22 of the injection molding machine moves forward, and the forward movement pushes the ejecting force buffer portion 19a. The projecting force buffering portion 19a presses the projecting plate 21, whereby the ejector pin 17 is projected. In such an operation, the projecting force buffering portion 19a has a projecting force necessary for the ejector pin 17 to release the molded product from the movable core portion 14 and does not cause deformation such as whitening when the molded product is released. Up to the force received from the ejector rod 22.

The projecting plate 21 receives the projecting force from the projecting force buffering portion 19a, and moves together with the ejector pin 17 that is implanted. Then, the ejector pin 17 is projected to release the molded product from the movable core portion 14, and the molded product is taken out by a take-out robot (not shown) or the like. When the above take-up operation is completed, the ejector rod 22 retracts and moves to the position before the start of the ejecting operation.

As a result, the projecting force buffer portion 19a is released from the projecting force received from the ejector rod 22,
It returns to the state before the protrusion operation started. After that, the mold clamping operation is performed by the injection molding machine, and the injection process is performed, as in normal injection molding. The above is defined as one process, and this process is repeated.

In such an embodiment, with a simple structure in which the protruding force buffering portion 19a is fixed to the protruding plate 21 with respect to the mold, it is possible to eliminate deformation such as whitening during protruding of the molded product.

(Embodiment 2) FIG. 2 shows Embodiment 2, in which only the points different from Embodiment 1 are described, the same components are assigned the same reference numerals, and the description thereof is omitted. In the above, reference numeral 24 denotes an ejector pin (hereinafter, referred to as a spring-loaded ejector pin 24) to which a metal coil spring 30 is attached in the axial direction, and particularly when ejecting a molded product,
Arbitrary numbers are arranged at arbitrary positions where deformation such as whitening is likely to occur or deformation is expected. The metal coil spring 30 of the ejector pin 24 with a spring projects and acts as a force buffer.

By changing the elastic modulus of the metal coil spring 30 of the ejector pin 24 with spring, the protrusion force when the molded product is discharged can be adjusted. The ejector rod 25 of the molding machine passes through the hole 23 opened in the movable die mounting plate 11 like a normal die, and acts so as to push the ejecting plate 21.

In the above-described structure, the steps up to the step of completing the mold opening operation of the movable mold 10 and advancing the ejector rod 25 of the molding machine are the same as those in the first embodiment. As the ejector rod 25 advances, the ejector rod 25 protrudes from the plate 2.
Ejector pin 1 that is pushed in and is planted in the protruding plate 21
7 and the spring-loaded ejector pin 24 start moving.

The ejector pin 17 separates the molded product from the movable core portion 14 like a normal mold, but the ejector pin 24 with spring has its metal coil spring 30 separate the molded product from the movable core portion 14. It is necessary to be molded, and when the molded product is released, no deformation such as whitening occurs,
The force received from the ejector rod 25 is buffered. These ejector pin 17 and ejector pin 24 with spring
After the molded product is released from the movable core portion 14 by the protrusion by, the same as in the first embodiment.

In this embodiment, when the molded product is released from the mold,
For places where deformation such as whitening does not occur,
By arranging the normal ejector pins 17, the time required for releasing the molded product from the mold is shortened, and the cycle time per injection molding can be shortened.

(Third Embodiment) FIG. 3 shows a third embodiment, only the points different from the first embodiment are described, the same components are designated by the same reference numerals, and the description thereof will be omitted.

The ejector rod 26 in the figure is a component of the injection molding machine, and comprises a rod portion 28 and a polyurethane-based synthetic rubber 27 attached to the tip of the rod portion 28. Polyurethane synthetic rubber 2
Reference numeral 7 is a protruding force buffering portion arranged at the tip of the ejector rod 26, that is, between the rod portion 28 and the protruding plate 21. By changing the elastic modulus of the polyurethane-based synthetic rubber 27, the force transmitted from the ejector rod 26 to the plate 21 can be adjusted.

In the above-mentioned structure, the steps of completing the mold opening operation of the movable mold 10 and advancing the ejector rod 26 of the molding machine are the same as those in the first embodiment. While the ejector rod 26 advances and pushes the plate 26, the polyurethane-based synthetic rubber 27 is necessary for the ejector pin 17 to separate the molded product from the movable mold core portion 14 and separates the molded product. At the time of molding, the protruding force is buffered to the protruding force that does not cause deformation such as whitening, and is transmitted to the protruding plate 21 as the protruding force. After the protruding plate 21 moves together with the implanted ejector pin 17, the process is the same as in the first embodiment.

In such an embodiment, even in an injection molding machine that does not have the function of controlling either or both of the ejection pressure control and the speed control, it is possible to attach the ejection force buffering portion to the ejector rod and mount the die. Deformation such as whitening can be eliminated when releasing all molded products.

As described above, in the embodiment, by changing the elastic modulus of the elastic body and the viscosity of the viscous body of the protruding force buffering portion,
The ejector pin projects the molded product from the movable mold and adjusts the force. In this case, in general, the lower the elastic modulus and the lower the viscosity, the more the force received from the ejector rod can be absorbed, the molded product can be projected from the movable mold, and the force can be weakened. It can be prevented. However, if the force for ejecting the molded product from the movable mold is excessively weakened, the time required for releasing the molded product from the mold becomes long and the time for one injection molding also becomes long.
Therefore, it is preferable to adjust the elastic modulus of the elastic body and the viscosity of the viscous body of the projecting force buffering portion in consideration of the molding time.

Further, in each of the embodiments, the elastic body is a metal coil spring and a polyurethane-based synthetic rubber,
Although the viscous body was used as the oil damper, the material of the elastic body is not limited to this, and the material is not limited to metal or synthetic rubber, and the shape may be changed to a leaf spring or another spring instead of the coil spring. it can. Further, the shape of the polyurethane-based synthetic rubber can be variously modified. Further, as the viscous body, an air damper may be used instead of the oil damper.

[0038]

As described above, according to the present invention, the ejecting force of the ejector rod is not directly transmitted to the molded product even in the molding machine having no function of controlling either or both of the ejecting pressure control and the speed control. Therefore, when the molded product is discharged, the ejector pin bites into the molded product, and the trace thereof can be prevented from being deformed such as whitening with a simple structure and easily.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of Embodiment 1 of the present invention.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a sectional view of a third embodiment.

[Explanation of symbols]

 17 Ejector Pin 18 Metal Spring 19 Damper 21 Projection Plate 22 Ejector Rod

Claims (2)

[Claims] 1. A projecting force at the time of projecting a molded product is buffered to at least one of an ejector pin provided in a molding die, a projecting plate to which the ejector pin is attached, or an ejector rod constituting an injection molding machine. The molded product ejecting device is provided with a ejecting force buffering part for 2. A molding product or an injection molding machine equipped with the molding product ejecting device according to claim 1, or a molding product molded by a molding die and an injection molding machine.