KR19990065716A - Injection mold apparatus and injection molding method - Google Patents

Abstract

The present invention relates to an apparatus and a method for forming an injection molding having a plurality of holes having a high density of gaps. Conventionally, injection molding is not only difficult, but also has a problem of lowering mechanical strength due to strength reduction and unformed shape due to flow marks on the surface of the injection molding. Therefore, the present invention is a fixed mold; A movable mold coupled to the fixed mold to form a space; A core pin mold which moves to the internal injection molding surface of the fixed mold and forms a plurality of holes having a high density of spacing between the local parts of the injection molded solidified into the space; A core pin movable mold for moving the core pin mold to an internal injection molding surface of the fixed mold; The coaffin movable mold is composed of an injection-molded ejection ejection mold for ejecting an injection-molded product in the space portion in which a plurality of holes having a high density of gaps are formed, and a molten resin in the space formed by coupling a movable mold to the fixed mold. Performing an injection process for injecting; Raising the fixed mold lower side movable plate while overcoming the elastic force of the spring to move the core pin mold interlocked with the movable plate to the internal injection molding surface of the fixed mold to form a hole in the injection part in the space; Cooling the core pin by lowering the restoring force of the spring mold; The fixed mold lower side eject plate is raised so that ejection by the eject pin of the eject plate may be performed, thereby preventing unformed defects and flow marks on the surface of the injection-molded product, as well as strength. Is more effective.

Description

Injection mold apparatus and injection molding method

The present invention relates to an injection mold apparatus and an injection molding method for producing an injection molded article having a plurality of holes having a high density of gaps therebetween.

Generally, the injection mold apparatus includes a mold part 1 and an injector part 5 for injecting molten resin into the mold part 1, as shown in FIGS. 1A to 1E. The mold part 1 includes a stationary mold 2 having a gate 2A at its center, a movable mold 3 coupled to the stationary mold 2 to form a space 2B therein, and the stationary mold 2. A take-out device 4 is provided for taking out the injection molded product 100B formed by filling a space 2B between the mold 2 and the movable mold 3 with a molten resin. In addition, the injector 5 is installed on the cylinder 6 in contact with the gate 2A of the fixed mold 2 and the upper side of the cylinder 6 so as to communicate with the inside of the cylinder 6, and the cylinder (6) a hopper 7 which allows the molding material 100 to be introduced into the inside, and a molding material which is installed on the outer surface of the cylinder 6 and introduced into the cylinder 6 through the hopper 7 ( Heater 8 which makes 100 a fluid melt resin by heating, and a molding material which is provided inside the cylinder 6 and becomes a fluid melt resin by heating of the heater 8 by forward movement by rotation. A transfer screw 9 for pushing the 100 to the tip end nozzle 6A side of the cylinder 6 and a rear side of the transfer screw 9 for forward and reverse rotation of the transfer screw 9; A driving device 9A for moving forward and backward is provided. In the conventional injection mold apparatus configured as described above, the molding material 100 is first introduced into the hopper 7, and the injected molding material 100 is introduced into the cylinder 6 while being installed on the outer surface of the cylinder 6. The heating of the heater 8 changes the molten resin 100A having fluidity. In addition, the molten resin 100A having the fluidity is pushed to the front end nozzle 6A side of the cylinder 6 by the rotation and forward transfer of the transfer screw 9 provided in the cylinder 6, and the nozzle ( The molten resin transferred to 6A) passes through the nozzle 6A at high pressure to inject molten resin into the mold part 1. The molten resin 100A injected into the mold part 1 is formed by the combination of the fixed mold 2 and the movable mold 3 through a gate 2A formed at an intermediate portion of the fixed mold 2. The molten resin 100A is filled into the space part 2B in the mold part 1, and when the filling is completed, the transfer screw 9 in the cylinder 6 stops without moving forward to maintain a constant pressure. It is. Then, after cooling for a predetermined time, it is taken out by the take-out device 4 of the mold part 1. That is, the molding process of the injection mold apparatus includes the step of forming a space portion 2B therein by coupling the stationary mold 2 and the movable mold 3 together; An injection step of injecting the molten resin (100A) into the space (2B); When the filling of the molten resin 100A to the space 2B is completed, the operation of the transfer screw 9 for forwarding the molten resin 100A to the front end nozzle 6A side of the cylinder 6 is stopped to maintain a constant pressure. A holding step to ensure; A cooling step of cooling the molten resin (100A) in the space portion (2B); The molten resin 100A is cooled and solidified, and the ejected injection molded product 100B is taken out. On the other hand, the resin is usually about 10 to 15% by volume shrinkage when cooling from high temperature to low temperature, the holding step is to supplement the molten resin (100A) as the volume shrinkage in the cooling step to maintain a constant pressure It is a step to do it.

However, such a conventional injection mold apparatus and a method of manufacturing an injection molded product not only generate a flow trace of a resin on the surface of an injection molded product when the injection molded product having a plurality of holes having a high density of intervals, such as a speaker of a television receiver, There was a problem that the mechanical strength is lowered. In addition, defects often occur due to unmolding phenomena, and at this time, even if the paint is sprayed on the exterior of the product, the degree is so severe that the marking is easily identified, and there is a problem that the product is damaged during the drop test performed at the development stage. . Therefore, an object of the present invention is to make it easier and more robust to manufacture an injection molding having a plurality of holes having a high density of gaps.

1A, 1B, 1C, 1D, and 1E illustrate a configuration and molding process of a conventional injection mold apparatus.

Figure 1a is a sectional view showing the mold closing step.

Figure 1b is a sectional view showing the injection step.

Figure 1c is a cross-sectional view showing the pressure holding step.

1d is a sectional view showing a cooling step.

Fig. 1E is a sectional view showing a taking out step.

Figure 2 is an exploded perspective view showing a mold structure of the present invention.

3 is an internal cross-sectional view of the coupled state of FIG.

4A, 4B, 4C, and 4D show the molding process according to the present invention.

Figure 4a is a sectional view showing the injection step.

Figure 4b is a sectional view showing the pressure holding step.

4C is a sectional view showing a cooling step.

4D is a sectional view showing a taking out step.

Figure 5 is a flow chart illustrating a simplified molding process of the present invention.

Figure 6 is a plan sectional view showing the flow of molten resin around the core pin according to the present invention.

Figure 7 is a longitudinal sectional view showing a flow state of the molten resin filled into the space portion of the present invention.

8 is a graph showing the pressure curve inside the mold of the present invention.

** description of the symbols for the main parts of the drawings **

10: mold part 20: fixed mold

21: gate 22: space part

23: pressure sensor 24: injection molding surface

30: movable mold 40: core pin mold

41: core pin plate 42: heating element

43: core pin 50: core pin movable mold

51: connecting pin 52: spring

53: movable plate 60: injection molding mold

61: eject plate 62: eject pin

Fixed mold and to achieve the object of the present invention; A movable mold coupled to the fixed mold to form a space; A core pin mold which moves to the internal injection molding surface of the fixed mold and forms a plurality of holes having a high density of spacing between the local parts of the injection molded solidified into the space; A core pin movable mold for moving the core pin mold to an internal injection molding surface of the fixed mold; An injection mold apparatus is provided which comprises an injection-molding ejection ejecting mold for ejecting an injection-molded product in the space part in which a plurality of holes having a high density of gaps are formed by the core pin movable mold. In addition, the core pin mold is composed of a core pin and a plurality of core pin, characterized in that the core plate is provided with a heating element for heating the core pin. The core pin movable mold may include a movable plate which is lifted from the lower side of the core pin plate, a connection pin that connects the core pin plate and the movable plate, and the movable plate is compressed when the movable plate is raised and is expanded by its own expansion force. It is characterized by consisting of a spring to lower the. In addition, the injection molding eject pin mold is characterized by consisting of an eject plate which is lifted from the lower side of the fixed mold, and an eject pin vertically installed on the eject plate in a manner that penetrates the fixed mold. And the present invention configured as described above comprises the steps of performing an injection process for injecting molten resin into the space formed by coupling the movable mold to the fixed mold; Raising the fixed mold lower side movable plate while overcoming the elastic force of the spring to move the core pin mold interlocked with the movable plate to the internal injection molding surface of the fixed mold to form a hole in the injection part in the space; Cooling the core pin by lowering the restoring force of the spring mold; There is provided a method of manufacturing an injection mold of the injection mold apparatus, comprising the step of raising the fixed mold lower side eject plate to perform the ejection by the eject pin of the eject plate.

Hereinafter, the structure of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is an exploded perspective view showing a mold structure of the present invention, Figure 3 is an internal cross-sectional view of the combined state of FIG. 4A, 4B, 4C, and 4D show a molding process according to the present invention, FIG. 5 is a flow chart illustrating a molding process according to the present invention, and FIG. 6 is a melting around the core pin according to the present invention. Fig. 7 is a longitudinal sectional view showing the flow state of the resin, Fig. 7 is a longitudinal sectional view showing the flow state of the molten resin filled into the space portion of the present invention, Fig. 8 is a graph showing the pressure curve inside the mold of the present invention. As shown therein, the present invention comprises a mold part 10 and an injector part 5. The injector part 5 has the same configuration as the conventional one, and the mold part 10 is as shown in FIG. That is, the mold part 10 is formed so that the fixed mold 20 having the gate 21 and the fixed mold 20 are combined with the space 22, that is, the resin injected into the desired shape. Movable mold 30 is provided to form an empty space. In addition, the fixed mold 20 is equipped with a pressure sensor 23 to detect the pressure in the space portion 22 formed by the combination of the fixed mold 20 and the movable mold 30. And the inside of the movable mold 30 is provided with a core pin mold 40 to move to the internal injection molding surface 24 of the fixed mold (20). The core pin mold 40 is formed in a structure in which a plurality of core pins 43 are formed on the top surface of the core pin plate 41 to form a plurality of holes having a high density of spacing therebetween, The pin plate 41 is provided with a heating element 42 such as a heater is configured to heat the core pin 43. Along with the core pin 40 is provided with a core pin movable mold 50 which is raised by the operation of the detection signal of the pressure sensor 23 mounted on the fixed mold (20). The core pin movable mold 50 has a pair of connecting pins 51 connected between the movable plate 53 and the core pin mold 40 in parallel with each other in a vertical line,

A spring 52 is installed on the connecting pin 51 to support the movable plate 53 in a downward direction at all times. And the lower side of the movable plate 53 is provided with an injection molding eject mold 60 to take out the injection molded in the space portion 22 between the fixed mold 20 and the movable mold 30 in a completed molding state, The injection mold ejection mold 60 has a structure in which an eject pin 62 penetrating the movable mold 30 is installed in a vertical direction on one side surface of the eject plate 61.

The following describes the molding process and operation of the present invention configured as described above.

First, the worker puts the molding material 100 into the hopper 7 installed on the cylinder 6 of the injector 5 as in the prior art, and the injected molding material 100 moves into the cylinder 6. Then, it is heated and melted by the heater 8 outside the cylinder 6 to change into a flowable molten resin. This fluid melted resin 100A is pushed toward the front end side nozzle 6A side of the cylinder 6 by a transfer screw 9 inside the cylinder 6 which is rotated in the forward direction by the drive device 9A again. The injection molten resin 100A is injected into the space 22 between the stationary mold 20 and the movable mold 30 through the gate 21 of the stationary mold 20 at a high pressure. The space 22 is filled with the molten resin 100A. At this time, the internal pressure of the space 22 is rapidly increased as shown in the internal pressure curve as shown in FIG. 8, and the pressure change thereof is detected by the pressure sensor 23 mounted on the fixed mold 20. The lower movable plate 53 of the movable mold 30 is raised while overcoming the elastic force of the spring 52. Accordingly, by moving the core pin mold 40 connected to the movable plate 53 and the connecting pin 51 to the injection molding surface 24 inside the fixed mold 20, the density of the interval between the local parts of the injection molding is high. To form a plurality of holes, a plurality of core pins provided on the upper surface of the core pin plate 41 by the heating element 42 provided in the core pin plate 41 of the core pin mold 40 ( 43) is heated. In addition, the molten resin 100A filled in the space 22 between the stationary mold 20 and the movable mold 30 has an inner contact surface 20A of the mold 20, 30 as shown in FIG. 7. On the upper and lower surfaces in contact with the 30A, solidifying layers 110A and 110B having a predetermined thickness are formed, and a fluidized fluid layer 110C is formed between the solidifying layers 110A and 110B and heated by the heating element 42. The coa pin 43 is to melt through the solidified layer (110A) (110B) by heat, and the molten amount is to replenish the molten resin because the volume shrinks due to cooling during the pressure holding process. After a few seconds have elapsed in this state, the movable force of the movable plate 53 is released and the core pin mold 40 connected to the core pin mold 40 is connected to each other by the connecting pin 51 by the elastic force of the compressed spring 52. The plate 53 is lowered again to return to the original position, and enters the cooling process. In addition, the injection-solidified product cooled through the cooling process is opened by the rise of the eject plate 61 and the eject pin 62 of the injection-molded mold 60 provided on the lower side of the movable mold 30 together with the mold opening. Will be able to take out.

As described above, the present invention forms a plurality of holes having a high density of gaps by melting and drilling the heated coa pin after the injection process is performed in the absence of coa pin, and thus flows on the surface of the unmolded defect and the injection molded product as in the prior art. Not only does the mark not occur, there is an effect that can increase the strength more.

Claims (5)

A fixed mold; A movable mold coupled to the fixed mold to form a space; A core pin mold which moves to the internal injection molding surface of the fixed mold and forms a plurality of holes having a high density of spacing between the local parts of the injection molded solidified into the space; A core pin movable mold for moving the core pin mold to an internal injection molding surface of the fixed mold; The injection mold apparatus, characterized in that the injection molding injection ejection mold for taking out the injection in the interior of the space portion is formed a plurality of holes having a high density of gap between the core pin movable mold. The injection mold apparatus according to claim 1, wherein the coffin pin is composed of a coffin pin and a plurality of coffins. The injection mold apparatus according to claim 2, wherein a heating element for heating the core pin is provided at a predetermined position of the core plate. According to claim 1 or 2, wherein the core pin movable mold is movable plate lifted from the lower side of the core pin plate, a connecting pin for connecting the core pin plate and the movable plate, and when the movable plate is raised Injection mold apparatus, characterized in that consisting of a spring is compressed and descending the movable plate by its own expansion force. Performing an injection process of injecting molten resin into the space formed by coupling the movable mold to the fixed mold; Raising the fixed mold lower side movable plate while overcoming the elastic force of the spring to move the core pin mold interlocked with the movable plate to the internal injection molding surface of the fixed mold to form a hole in the injection part in the space; Cooling the core pin by lowering the restoring force of the spring mold; And raising the fixed mold lower side eject plate to perform ejection by the eject pin of the eject plate.