JP2000301570A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding machine which is of a runner structure such as not becoming complicated on the parting line of a mold, although the mold is of a multi-cavity type and requires only a low percentage of increase in the necessary mold clamping force. SOLUTION: A cavity retainer plate 11, an intermediate retainer plate 15 and a movable retainer plate 13 are arranged in one mold opening/closing direction in such a manner that the adjacent retainer plates are mutually openable/ closable, and thus two parting lines 17, 19 are provided. In addition, a required cavity 35, a runner 39 and a nozzle touch 41 which lead to the cavity 35 are formed in each of these parting lines 17, 19. Further, a heating cylinder 5 for injecting a molten resin into the cavity 35 has two injection nozzles 65R, 65L. A runner 69 is formed to connect a resin flow path 61a to the injection nozzles 65R, 65L in the heating cylinder 5 and a band heater 67 for heating the runner 69 is provided. Besides, an ejector mechanism 51 is mounted on the cavity retainer plate 11 and the movable retainer plate 13 respectively. Thus it is possible to offset each one half of the resin pressure on each of the parting lines with each other half of the resin pressure on the other parting line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine including a mold device, a mold clamping device, an injection device, and the like.
The present invention relates to a novel injection molding machine capable of obtaining a large number of pieces even with a small mold clamping force.

[0002]

2. Description of the Related Art An injection molding machine for molding a product using a molding material such as a synthetic resin is basically a mold device having a cavity defining an outer shape of the product, and a mold plate for opening and closing the mold plate of the mold device. Further, it comprises a mold clamping device for pressing, an injection device for injecting a molding material into a cavity of a mold, and the like. The mold device is equipped with an eject mechanism and a water cooling mechanism for releasing the molded product, the mold clamping device has a pneumatic or hydraulic actuator, and the injection device has a screw inside the cylinder And an injection nozzle attached to the end of the heating cylinder.

[0003] The structure of the conventional mold apparatus generally has only one fixed-side mold plate and one movable-side mold plate, and therefore has only one parting line. Therefore, when a large number of products are taken, a large number of necessary cavities are arranged on one parting line.

FIG. 6 shows an example a of a parting surface of a mold plate when four conventional mold devices are used. The parting surface a has a sprue tip opening b at its center.
Are formed. Four cavities c are formed at positions equidistant from each other from the tip opening b, and these cavities c are connected to the tip opening b by runners d of the same length. e indicates a runner gate. Therefore, the molten resin injected from the injection device (not shown) through the opening b of the sprue is injected into each cavity c through the runner d and the gate e. In addition, as a main gate method in the mold apparatus, there is a direct gate method in which a sprue is directly connected to a cavity, in addition to the side gate method shown in FIG.

[0005]

The conventional injection molding machine has a problem that, in the case of multi-cavity molding, the mold runner structure becomes complicated and a high mold clamping force is required. In other words, when a large number of cavities are to be obtained, the required number of cavities must be developed on one parting line, so that the number of runners d and gates e increases in proportion to the increase in the number of cavities. The runner structure becomes very complicated. Also, as is known, the mold clamping force (F) required for the mold clamping device increases with an increase in the projected area of the cavity, so that the greater the number of cavities, the greater the required mold clamping force. Will be. As a result, a large-sized actuator is required, a huge frame is required, and the apparatus is very large and expensive.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has a large number of individual pieces. It is an object of the present invention to provide an injection molding machine that requires a small increase in the mold clamping force.

[0007]

In order to achieve this object, an injection molding machine according to the present invention is provided such that three or more mold plates arranged in one mold opening and closing direction can be freely opened and closed by adjacent ones. A mold device having a plurality of parting lines and having a runner opened at one end of each parting line and communicating with the cavity; a mold clamping device for opening and closing the mold device; and a molding material in the cavity. An injection device having a heating cylinder for injecting, the heating cylinder,
At least the same number of injection nozzles as the number of the runners are provided, and after the closing of the mold apparatus is completed, the injection nozzle is pressed against the entrance of the runner to inject the molding material.

According to this structure, the projection surface of the cavity provided on one parting line overlaps with the projection surface of the cavity provided on another parting line at all or most of the time. ,
The pressure applied to the mold clamping device can be offset. That is, almost half of the material pressure applied to the inner wall of the cavity on each parting line and almost half of the material pressure applied to the inner wall of the cavity on another adjacent parting line cancel each other out. This is because it is sufficient that the mold clamping force is set based only on the material pressure applied to the inner wall of the cavity on one parting line. Therefore, even a small-sized injection molding machine can easily realize multi-cavity molding. Further, since the cavities can be distributed to a plurality of parting lines, the structure of the runner and the gate on each parting line can be simplified, and the manufacturing cost of the mold can be reduced accordingly.

According to a second aspect of the present invention, in the injection molding machine according to the first aspect, all the cavity patterns in each parting line are made identical. In this way, the projection surfaces of the cavities on each parting line can be completely matched.

According to a third aspect of the present invention, in the injection molding machine according to the first aspect, the shape of the cavity is made different between the parting lines. The present invention
By utilizing the fact that the invention of claim 1 has a plurality of parting lines, it is possible to simultaneously perform molding of a deformed product. In practicing the present invention,
Depending on the shape and number of the cavities, the inner diameter of the injection nozzle, the runner gate, and other factors related to the resin pressure (pressure on the inner surface of the cavities) may be made different depending on the size of the cavities.

According to a fourth aspect of the present invention, in the injection molding machine according to any one of the first to third aspects, the injection device has a structure in which a plurality of injection nozzles are provided at a tip of one heating cylinder, and a material in the heating cylinder is provided. The runner is continuous between the flow path and the injection nozzle and includes a heater for heating the runner. Therefore, only one injection device is required, and the solidification of the material by the runner in the heating cylinder can be reliably prevented.

According to a fifth aspect of the present invention, there is provided the injection molding machine according to any one of the first to fourth aspects, wherein each of the fixed-side mold plate and the movable-side mold plate, and the fixed-side mold plate or the movable-side mold plate. In this example, two parting lines are provided by providing an openable and closable intermediate mold plate, and an ejection mechanism is mounted on each of the fixed mold plate and the movable mold plate. With this configuration, the eject mechanism can be easily mounted, and the molded product can be reliably released.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an injection molding machine 1 according to an embodiment of the present invention will be described with reference to the drawings. Injection molding machine 1
Is composed of a mold device, a mold clamping device, an injection device, and the like. In the drawings, only the main part of the mold device 3 and the tip of the heating cylinder 5 of the injection device are shown. .

The mold apparatus 3 has three mold plates arranged along the mold opening and closing direction. That is, reference numeral 11 denotes a fixed-side template, and 13 denotes a left side of the fixed-side template 11 (a leftward direction in FIG. 1 is a left side, and a downward direction in FIG. 1 is a front side. When saying
Follow this direction. ) Shows the movable mold plate arranged in 1).
Reference numeral 5 denotes an intermediate template located between the fixed template 11 and the movable template 13.

The fixed mold plate 11 has a parting surface 17a on the left side, and the movable mold plate 13 has a parting surface 19a on the right side. Intermediate template 15
The left and right sides are parting surfaces 17b and 19b. One parting line 17 is formed by the parting surface 17a of the fixed mold plate 11 and the right parting surface 17b of the intermediate mold plate 15, and the parting surface 19a of the movable mold plate 13 and the Another parting line 19 is constituted by the left parting surface 19b.

Reference numeral 21 denotes a fixed-side mounting plate fixed to a fixed base (not shown). The fixed-side mold plate 11 is mounted on a left side surface of the fixed-side mounting plate 21 via a spacer block 23. Reference numeral 25 denotes a movable-side mounting plate, and the movable-side mold plate 13 is mounted on a right side surface of the movable-side mounting plate 25 via a spacer block 27.

The right end of a guide rod (not shown) extending in the left-right direction is fixed to the corners at the upper and lower ends of the fixed-side mounting plate 21.
5 is slidably supported. Also, the movable side mounting plate 2
5 is equipped with a sub-clamping device (not shown) that uses a hydraulic cylinder or an air cylinder as a driving source, and a drive rod of the sub-clamping device is connected to the intermediate template 15, and the sub-clamping device is By driving, the intermediate template 1
5 is opened and closed with respect to the movable mold plate 13. A main mold clamping device (not shown) is disposed on the left side of the movable mounting plate 25. The main clamping device integrally moves the movable mounting plate 25, the movable mold plate 13, and the intermediate mold plate 15 right and left. Moved in the direction.

Opening and closing between the fixed mold plate 11, the movable mold plate 13, and the intermediate mold plate 15 is performed in the following order. That is, as shown in FIGS. 1 and 5, a state in which the fixed-side mold plate 11, the movable-side mold plate 13, and the intermediate mold plate 15 are all separated from each other is a mold open state. First, as shown in FIG. 2, the intermediate template 15 is moved to the left by the sub-clamping device and closed with respect to the movable-side template 13 (parting line 19 is closed). Next, the movable-side mounting plate 25 is moved rightward by the main mold-clamping device, whereby the intermediate template 15 is closed with respect to the fixed-side template 11 as shown in FIG. 3 (parting line 17). Is closed). The mold opening is performed in the reverse order of the mold closing order described above.

On each of the parting surfaces 17a and 19a of the fixed mold plate 11 and the movable mold plate 13, a cavity half 31 and a runner 39 having the same shape are formed. It is continuous through 37. The cavity halves 33 having the same shape are formed on both parting surfaces 17b and 19b of the intermediate mold plate 15. Therefore, the fixed side template 11
When the mold half and the intermediate mold 15 are closed, a pair of cavities 35 are defined by the cavity halves 31 and 33, and when the movable mold plate 13 and the intermediate mold 15 are closed, these cavity halves 31 and 33 are closed. Another set of cavities 35 is defined by 31 and 33. Therefore, the patterns (the shapes and numbers of the cavities 35 and the runners 39) on the left and right parting lines 17 and 19 completely match each other.

As can be seen from the drawing, the cavities 35 and the runners 39 on each parting line are aligned in the left-right direction,
That is, they are provided at exactly the same position when viewed from the mold opening and closing direction. Therefore, despite the fact that there are two cavities 35 and two runners 39, respectively, the projected area is the size of one cavity 35 and one runner 39.

Small recesses are formed at the end of the runner 39 and the parting surfaces 17b and 19b of the intermediate mold plate 15 corresponding to the end of the runner 39. As a result, a nozzle touch 41 (see FIGS. 2 and 3) that forms a substantially hemispherical concave portion by the concave portion is formed. This nozzle touch 41 (runner 3
9) is a portion that functions as an opening to which an injection nozzle described later is pressed against, and has a radius of curvature larger than the radius of curvature of the tip end surface of the injection nozzle.

An ejection mechanism 51 is mounted on the fixed mold plate 11 and the movable mold plate 13. That is, a hydraulic cylinder (or an air cylinder) 53 is fixed to the opposite side surfaces of the fixed-side and movable-side mounting plates 21, 25, and the ends of the piston rod 55 are provided with the template plates 11, 13.
Is fixed behind the eject plate 57. The eject pin 59 protruding from the eject plate 57 is slidably passed through a through hole reaching the bottom surface of the cavity half 31. Eject plate 57
Is in the retracted position shown in FIG. 1 and the like, except when the molded product is taken out. In this state, the tip surface of the eject pin 59 is
It forms a part of the bottom surface.

The heating cylinder 5 is arranged on the rear side of the mold apparatus 3. The heating cylinder 5 is housed in a cylinder 61 provided in a front-rear direction, that is, a direction extending in a direction orthogonal to the mold opening and closing direction of the mold apparatus 3, and a resin flow channel 61 a which is an internal space of the cylinder 61. Screw shaft 63 (only the head portion is shown in the drawing), and two left and right injection nozzles 65R and 65 attached to the tip end surface of cylinder 61.
L, and a number of band heaters 67 (only those provided at the tip of the cylinder 61 are shown in the drawing) and the like, which are externally fitted to the cylinder 61. A runner 69 is connected between the tip of the resin flow path 61a and the injection nozzles 65R and 65L, and the runner 69 is constantly heated by a band heater 67.

The two injection nozzles 65R and 65L are
It is provided at a position facing each of the two parting lines 17 and 19 in a state where the mold closing of the mold apparatus 3 is completed (see FIG. 3). Then, the heating cylinder 5 is moved in the front-rear direction by a heating cylinder moving mechanism (not shown), and in a state other than when performing injection, the injection nozzles 65R, 65L are connected to the template plates 11, 13, 15 as shown in FIG.
Is held at a standby position that is separated from the rear by a certain distance. The injection molding machine 1 is configured as described above.

Next, the operation of the injection molding machine 1 will be described. As described above, when there is a mold closing command from the mold opening state, the intermediate mold plate 15 and the movable mold plate 13 are closed, then the intermediate mold plate 15 and the fixed mold plate 11 are closed, and the nozzle The touch 41 is formed (the state shown in FIG. 3). In this state, the right injection nozzle 65R of the heating cylinder 5 faces the nozzle touch 41 of the right parting line 17, and the left injection nozzle 65L faces the nozzle touch 41 of the left parting line 19.

When the mold closing is completed in this way, the heating cylinder 5 advances at a predetermined timing, and the injection nozzles 65R and 65L are individually pressed against the nozzle touch 41 as shown in FIG. When the completion of the pressure contact is detected, the screw shaft 63 moves forward and injects the molten resin into the cavity 35. That is, the molten resin in the cylinder 61 flows from the resin flow path 61 a to the runner 69 and the injection nozzle 6.
The molten resin is injected into the runners 39 of the mold plates 11 and 13 through 5R and 65L, and the injected molten resin is injected into the cavity 35 through the gate 37. After the molten resin is injected into the cavity 35, the heating cylinder 5 is held at the forward position until a predetermined pressure holding time elapses.

Since the mold unit 3 has two cavities 35, the resin pressure applied to the mold unit 3 is twice the resin pressure A required for each cavity 35, but is applied to the mold clamping unit. The pressure is approximately the resin pressure A for one cavity. That is, about half of the respective resin pressures A applied to the inner surfaces of the left and right cavities 35 act on the parting surfaces 17b and 19b of the intermediate mold plate 15, and these are offset from each other. Therefore, although there are two cavities 35, the mold clamping force required for the mold clamping device is sufficient to withstand the resin pressure for one cavity.

When the molten resin in the cavity 35 is cooled and solidified, a product 71 is formed. At a predetermined timing, the heating cylinder 5 retreats to the standby position, and then the mold is opened. And
When the mold opening is completed, the eject plate 57 moves forward as shown in FIG. 5, pushes the product 71 out of the cavity 35, and waits for the next mold closing command. The operation of the injection molding machine 1 is performed as described above.

Although the embodiment of the present invention has been described in detail above, the specific configuration is not limited to this embodiment, and there are changes in the design without departing from the gist of the present invention. Are also included in the present invention. For example, in the embodiment, two parting lines are provided by three mold plates, but the number of the parting lines is limited as long as the molded product can be ejected.
Any number of 2 or more is acceptable.

Further, in the embodiment, one cavity is provided in one parting line. However, the number of cavities may be any number, and one runner is provided for one parting line. It is not limited to. Furthermore, in the embodiment, the nozzle touch, which is the entrance of the runner of the template, is concave and the tip end surface of the injection nozzle is spherical. However, in implementing the present invention, the nozzle touch or the nozzle touch Both the tip and the tip surface of the injection nozzle may be flat. In addition, it is a matter of course that the specific shape or the driving means of each part such as the mold plate and the injection nozzle which constitute the present invention is not limited to the one shown in the embodiment. It is also conceivable to use a motor and a ball screw.

[0031]

As described above, in the injection molding machine of the present invention, the projection surface of the cavity provided on one parting line is all or large with the projection surface of the cavity provided on another parting line. Since the portions overlap each other, the pressure applied to the mold clamping device can be offset by the overlapped area. Almost half of the material pressure applied to the inner wall of the cavity on each parting line and almost half of the material pressure applied to the inner wall of the cavity on another adjacent parting line cancel each other, so that the mold clamping required for the mold clamping device is completed. This is because the force only needs to be set based on the material pressure applied to the inner wall of the cavity on one parting line. Therefore, even a small-sized injection molding machine can easily realize multi-cavity molding. Also, since the cavities can be distributed over multiple parting lines, the runner structure on each parting line can be simpler,
Accordingly, the manufacturing cost of the mold can be reduced.

According to the second aspect of the present invention, the projection planes of the cavities on each parting line can be completely matched.

According to the third aspect of the present invention, it is possible to simultaneously perform the molding of the deformed product.

According to the fourth aspect of the present invention, only one injection device is required, and it is possible to reliably prevent the material from being solidified by the runner in the heating cylinder.

According to the fifth aspect of the present invention, the eject mechanism can be easily mounted, and the molded product can be reliably released.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view showing an initial state of an injection molding machine according to an embodiment of the present invention.

FIG. 2 is a horizontal sectional view showing a state in which a part of the injection molding machine shown in FIG. 1 is closed.

FIG. 3 is a horizontal sectional view showing a state in which the mold closing of the injection molding machine shown in FIG. 1 is completed.

FIG. 4 is a horizontal cross-sectional view showing a state where a heating cylinder is advanced in the injection molding machine shown in FIG.

FIG. 5 is a horizontal sectional view showing an ejected state of the injection molding machine shown in FIG.

FIG. 6 is a schematic front view showing an example of a conventional mold device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection molding machine 3 Mold apparatus 5 Heating cylinder 11 Mold plate (fixed mold plate) 13 Mold plate (movable mold plate) 15 Mold plate (intermediate mold plate) 17 Parting line 19 Parting line 39 (Mould machine ) Runner 51 Eject mechanism 61a Material flow path 65R Injection nozzle 65L Injection nozzle 67 Heater 69 Runner (of heating cylinder)

Claims (5)

[Claims] A plurality of parting lines are provided by providing three or more template plates arranged in one mold opening / closing direction so that they can be opened and closed by adjacent ones, and an opening is provided at one end of each parting line. A mold device provided with a runner communicating with the cavity, a mold clamping device for opening and closing the mold device, and an injection device having a heating cylinder for injecting a molding material into the cavity, wherein the heating cylinder has An injection molding machine having at least the same number of injection nozzles as the number of the runners, and injecting a molding material by pressing the injection nozzle against an entrance of the runner after the mold device is completely closed. 2. The injection molding machine according to claim 1, wherein
An injection molding machine wherein all cavity patterns in each parting line are made identical. 3. The injection molding machine according to claim 1, wherein
An injection molding machine characterized in that the shape of the cavity is different between the parting lines. 4. The injection molding machine according to claim 1, wherein the injection device has a structure in which a plurality of injection nozzles are provided at a tip of one heating cylinder, and a material flow path in the heating cylinder and an injection nozzle. And a heater for heating the runner. 5. The injection molding machine according to claim 1, wherein each of the fixed-side mold plate and the movable-side mold plate is supported by the fixed-side mold plate or the movable-side mold plate to be openable and closable. An injection molding machine characterized in that two intermediate parting plates are provided to provide two parting lines, and an ejection mechanism is mounted on each of a fixed-side mold plate and a movable-side mold plate.