JP2009000854A - Injection molding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding device capable of manufacturing excellent injection-molded products while reducing injection pressure and clamping pressure. <P>SOLUTION: A plurality of injection units 12 are mounted to injection ports 22 communicating with a cavity 10. Each injection unit 12 injects a resin material at the injection speed to the extent of filling each injection region in the cavity 10, and the resin material injected from each injection unit 12 contacts and joins a resin material injected from the adjacent injection unit 12. Since the resin material is injected from the plurality of injection units 12, the injection pressure can be reduced and thereby clamping force is also reduced. Further, since each injection unit 12 is provided with a servo motor 36, a heater 28 and a material feeder 26, each injection unit 12 can be independently controlled, and various molded products can be formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an injection molding apparatus, and more particularly to a low pressure injection molding apparatus that injects a resin material into a mold at a low pressure.

  The injection molding apparatus includes an injection plunger that injects resin into a cavity formed between a fixed mold and a movable mold, and a mold clamping device that clamps the fixed mold and the movable mold (Patent Document 1). In such an injection molding apparatus, resin is injected into the cavity from one injection plunger, but when a plurality of cavities are provided in the mold, the resin from the injection plunger branches in the mold. Distributed to each cavity by the runner.

  An injection molding apparatus having two injection plungers is known (Patent Document 2). This injection molding apparatus molds a so-called two-color molded product. The first color resin is injected into the cavity from one injection plunger, and thereafter or simultaneously with the second color resin from the other injection plunger into the cavity. inject.

JP 2002-355856 A JP 2004-237460 A

In general, injection molding apparatuses such as these are required to inject a resin at a high injection pressure in order to shorten the molding cycle and improve productivity. However, in order to increase the injection pressure, an injection plunger with high injection capability (injection pressure) is required, and the mold clamping pressure required for the mold clamping device to withstand the high injection pressure also increases. There is a problem that the entire injection molding apparatus is enlarged.
In addition, when manufacturing large molded products, it is required to quickly spread the resin to every corner of the large cavity, which requires higher injection pressure and higher mold clamping pressure. There was a problem that the apparatus became very large.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an injection molding apparatus capable of producing an injection molded product with a low injection pressure.

  According to the present invention, an injection molding apparatus for injecting resin into a cavity of a mold having a plurality of resin injection ports, wherein the plurality of injection units and each injection unit communicate with resin injection ports having different cavities. A plurality of injection ports, and each injection unit has a plunger, a material supply means for supplying a resin material to the plunger, and a plasticizing means for plasticizing the resin in the plunger. A featured injection molding apparatus is provided.

  According to the present invention configured as described above, since a plurality of plungers and injection ports are provided, the resin can be injected simultaneously or sequentially from the plurality of plungers into the cavity. As a result, even if the injection pressure is low, the resin can be quickly spread to every corner of the cavity, so that the necessary mold clamping pressure is lowered. For this reason, structural strength required for the injection molding apparatus can be reduced, the structure of the injection molding apparatus can be simplified, and the downsizing and cost saving of the injection molding apparatus can be promoted. This is particularly useful when manufacturing large molded articles. Furthermore, the injection pressure required for each plunger is reduced.

  In addition, since a plurality of plungers are provided, the injection timing of the resin from the plunger, the injection conditions such as the injection amount and the injection speed can be set for each plunger. Therefore, it is possible to flexibly cope with the production of molded products having various shapes.

  Furthermore, since the plunger, the plasticizing means, and the material supply means are provided for each injection unit, the same kind or different kinds of materials can be supplied to each plunger. Therefore, for example, a plurality of types of materials can be injected into the cavities to perform multicolor molding, or when a plurality of cavities are formed in the mold, different materials can be injected into each cavity. Thus, the injection molding apparatus of the present invention can flexibly cope with various molding conditions.

  According to another aspect of the present invention, there is provided an injection molding apparatus for injecting resin into a cavity of a mold having a plurality of resin injection ports, wherein a plurality of injection units and each injection unit are respectively injected with a resin having a different cavity. A plurality of injection ports communicating with the inlet, each injection unit has a plunger, a material supply means for supplying a resin material to the plunger, and a plasticizing means for plasticizing the resin in the plunger, There is provided an injection molding apparatus characterized in that a cavity is assigned to each injection unit as an area where each injection unit can distribute resin, and the injection unit is arranged for each assigned area.

  According to the present invention configured as described above, the cavity is assigned to each injection unit as a region where one injection unit can spread the resin before curing, and the injection unit is arranged for each region. For this reason, the area | region filled with resin with one injection | pouring unit can be set smaller than before. Therefore, even if an injection unit having a low injection pressure is used, the resin can be spread over the entire cavity, and the required mold clamping pressure is reduced. In addition, since a good molded product can be obtained even when the injection pressure is lowered, the structural strength and the like necessary for the injection molding apparatus can be reduced, and the structure of the injection molding apparatus can be simplified. Further, it is possible to promote downsizing and cost saving of the injection molding apparatus.

  That is, the present invention sets the injection conditions (injection pressure, injection speed, injection amount, etc.) of the injection unit in advance, unlike the conventional injection molding apparatus that sets the injection conditions of the injection unit according to the shape of the cavity, A cavity area that can spread the resin when injected under this injection condition is allocated, and an injection unit is arranged in each area. Therefore, regardless of the shape of the cavity, a good molded product can be obtained while injecting the resin under the desired injection conditions. Further, since the injection conditions can be set as desired, it is possible to inject the resin at a low pressure without increasing the mold clamping pressure.

  In the present invention, preferably, each plunger is configured to sequentially inject resin into the cavity at different injection timings.

  According to such a configuration, since the resin is injected from the plurality of plungers while sequentially shifting the timing, the pressure applied to the mold can be further reduced. Therefore, the mold clamping pressure for clamping the mold can be further reduced.

  In the present invention, preferably, the plurality of injection ports are arranged in a lattice shape, and each plunger is configured to selectively inject resin according to the shape of the cavity.

  According to the present invention configured as described above, a plurality of injection ports are arranged in a lattice shape, and each plunger selectively injects resin in accordance with the shape of the cavity. The degree of freedom is high, and it is possible to deal with the production of molded products having various shapes. Further, even when a plurality of cavities are formed in the same mold, each cavity can be efficiently arranged in the mold.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is simplified or omitted.

[First Embodiment]
An injection molding apparatus according to a first embodiment of the present invention will be described. The injection molding apparatus according to the present embodiment is an injection molding apparatus that manufactures large molded articles such as automobile bumpers.
FIG. 1 is an overall perspective view schematically showing an injection molding apparatus 1 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a state where the mold 2 is attached to the injection molding apparatus 1 according to the first embodiment of the present invention.

  As shown in FIGS. 1 and 2, the injection molding apparatus 1 includes a lower platen 4 that contacts the lower surface of the mold 2, an upper platen 6 that contacts the upper surface of the mold 2, an upper platen 6, and a lower platen. A mold clamping device 8 that performs mold clamping and mold opening of the mold 2 by moving the 4 close to and away from each other, and an injection unit 12 that injects resin into a cavity 10 formed in the mold 2 are provided.

  The mold 2 includes a fixed mold 14 and a movable mold 16 that can move in the vertical direction with respect to the fixed mold 14. The mold 2 has a shape corresponding to the shape of the molded product between the fixed mold 14 and the movable mold 16. A cavity 10 is formed. A plurality of through holes are formed in the fixed mold 14 so as to communicate the upper surface of the fixed mold 14 and the inside of the cavity 10, and the upper surface opening of these through holes serves as a resin injection port 18 from the injection unit 12.

  In the present embodiment, a single cavity 10 is formed in the mold 2, and six through holes (resin injection ports 18) communicate with the cavity 10. Thus, in the present embodiment, a plurality of resin injection ports 18 are provided for one cavity 10. In the present embodiment, the gate formed in the mold 2 is a direct gate. Further, the fixed mold 14 and the movable mold 16 are formed with a cooling path (not shown) for cooling and solidifying the resin injected into the cavity 10. A cooling means 44 (see FIG. 4) for cooling the mold 2 by circulating a cooling medium therein is attached to the cooling path.

  The mold 2 is configured by joining a plurality of divided mold parts together with the fixed mold 14 and the movable mold 16. With such a configuration, the fixed mold 14 and the movable mold 16 of the mold 2 can be manufactured with a small cutting machine for each mold part, and therefore the mold 2 can be manufactured in a short period of time.

  The upper platen 6 is formed with the same number (6 in this embodiment) of the injection ports 12 of the injection units 12 as the plurality of resin injection ports 18 at positions corresponding to the resin injection ports 18 of the mold 2. By attaching the injection unit 12 to the attachment port 20, the front end opening of the injection unit 12 becomes a resin injection port 22.

  FIG. 3 is a partially broken view showing the injection unit 12 of the injection molding apparatus 1 according to the first embodiment of the present invention. Referring to FIG. 3 and FIG. 1 described above, each injection unit 12 includes a plunger 24, a material supplier 26 that supplies resin to the plunger 24, and a heater 28 that heats (plasticizes) the resin in the plunger 24. It has.

  The plunger 24 includes a cylinder 30 and a screw 32 that can move forward and backward in the cylinder 30. The plunger 24 is supported above the upper platen 6 by a guide rod 34 erected around the plunger 24. A servo motor 36 that rotationally drives the screw 32 is disposed above the guide rod 34, and the servo motor 36 is connected to the screw 32 via appropriate transmission means. When the rotation of the servo motor 36 is transmitted to the screw 32 by the transmission means, the screw 32 advances and retreats in the cylinder 30 while rotating around the shaft.

  Therefore, in this embodiment, since the screw 32 is driven by the servo motor 36, the resin injection operation can be controlled not by the injection pressure but by the injection speed. The resin injection speed can be controlled with high accuracy by the rotation angle of the servo motor 36. In addition, since one servo motor 36 is provided for each injection unit 12, the injection conditions such as the injection timing, injection speed, and injection amount of the resin from each injection unit 12 can be adjusted independently. it can.

  One material supply unit 26 is provided for each injection unit 12 and communicates with the space between the cylinder 30 and the screw 32 from the side surface of the cylinder 30 of the plunger 24 so that the resin material is supplied to this space. It is configured. Since one material feeder 26 is provided for each plunger 24, the same kind or different kind of material can be supplied to each plunger 24 according to the type of the molded product.

  The heater 28 is disposed outside the lower portion of the cylinder 30 of the plunger 24. The material supplied into the cylinder 30 from the material supply machine 26 is kneaded and plasticized by being heated by the heater 28 while being transferred toward the injection port 22 in the cylinder 30 by the screw 32. Therefore, in this embodiment, each injection unit 12 is provided with one plasticizing means, whereby the injection temperature of the resin of each injection unit 12 can be adjusted independently.

The injection molding apparatus 1 further includes control means 42 for controlling the injection operation of each injection unit 12 and the mold opening and mold clamping operations of the mold clamping device 8.
FIG. 4 is a block diagram showing a control configuration of the injection molding apparatus 1. The control means 42 is connected to the servo motor 36 and the heater 28 of each injection unit 12. The control means 42 is also connected to the mold clamping device 8 and the cooling means 44. The control means 42 outputs the rotation angle (rotation amount) and rotation speed signals to the servo motors 36 of each injection unit 12 separately to control the movement amount and movement speed of the screw 32 of each injection unit 12. . Accordingly, the injection amount and injection speed (injection pressure) of the resin of each injection unit 12 are independently adjusted by the control means 42. Further, the control means 42 independently controls the resin temperature in the plunger 24 of each injection unit 12 by separately outputting a resin heating temperature signal to the heater 28 of each injection unit 12.

Here, since the control means 42 controls the servo motor 36 of each injection unit 12 independently, it is possible to change the output timing of the signal output to each servo motor 36 simultaneously or mutually. Therefore, the injection of the resin from each injection unit 12 to the cavity 10 can be performed simultaneously or differently, and the injection timing of the resin can be controlled independently for each injection unit 12. It can be done.
Further, the control means 42 performs mold clamping of the mold 2 by outputting a mold clamping signal to the mold clamping device 8 before resin injection. The control means 42 cools the mold 2 by outputting a cooling signal to the cooling means 44 after completion of the resin injection by the injection unit 12. Then, the control means 42 opens the mold 2 by outputting a mold opening signal to the mold clamping device 8 after a predetermined time after cooling the resin.

  The injection units 12 are arranged at intervals such that when the resin is injected into the cavity 10 under predetermined injection conditions, the resins from the plurality of injection ports 22 are coupled to each other before solidifying. Therefore, the arrangement interval of each injection unit 12 is such that the resin injected from the injection port 22 at a predetermined pressure contacts the resin from the adjacent injection port 20 in the cavity 10 to form a weld line at the contact portion. It is set so that they can be coupled to each other without causing a decrease in strength at the contact portion. Further, the injection conditions such as the injection speed, injection amount, and injection timing of each injection unit 12 are appropriately set so that the resin from each injection port 22 can be reliably combined with the resin from the adjacent injection port 22.

  FIG. 5 shows an injection region of the resin material that each injection unit 12 injects (covers). As shown in FIG. 5, each injection unit 12 is in charge of a predetermined injection region 23 around the injection port 22. Each injection unit 12 is injected at an injection speed at which the resin material at the outer edge portion is not solidified even when the resin material reaches the outer edge of the injection region 23 at a predetermined injection pressure (low pressure).

  Here, the injection pressure (molding pressure) of the resin from the injection unit 12 is desirably a low pressure, and the “low pressure” is preferably in the range of, for example, 5 to 25 MPa. Moreover, it is preferable that the molding pressure of the injection molding apparatus 1 of this embodiment is about 1/10 to 1/2 with respect to 30 to 60 MPa of the molding pressure of a general injection molding machine. Thus, the molding pressure of the injection molding apparatus 1 of the present embodiment is very low compared to the molding pressure of a general injection molding machine. The molding pressure of the injection molding apparatus 1 of the present embodiment is set in consideration of various setting conditions such as the size and shape of the cavity 10, the number of installed injection units 12, the size and position of the injection port 22, and the like. The

  Specifically, when the arrangement of the injection unit 12 is determined, first, the cavity 10 is considered in consideration of the shape of the cavity 10 according to the injection conditions such as the injection speed, injection amount, injection resin temperature, etc. of the injection unit 12. Each injection unit serves as an injection region 23 in which the resin injected from one injection unit 12 expands without being completely solidified in the cavity 10 and can be combined with the resin from the adjacent injection unit 12. Assign to 12. Then, the injection ports 22 of the injection unit 12 are arranged one by one with respect to the injection region 23, and the arrangement of the resin injection ports 18 of the mold 2 is determined according to the arrangement of the injection ports 22. Accordingly, the shape and size of each injection region 23 differ depending on the injection conditions of the resin and the shape of the cavity 10. For example, when there is an elongated portion in a part of the shape of the cavity, it takes more time than other portions to spread the resin over the portion. Therefore, the injection region 23 including the elongated molded portion may be set smaller than the other injection regions 23 so as to be aligned with other injection times.

Note that the injection conditions of each injection unit 12 may all be the same or different. For example, the injection pressure of the injection unit 12 that injects into the injection region 23 having an elongated molded portion may be set higher than the injection pressure of the other injection units 12. That is, the injection conditions of each injection unit 12 can be varied within a predetermined injection condition range.
In the present embodiment, an injection region 23 is assigned to each injection unit 12 and an injection unit 12 is arranged for each injection region 23 so that the injection unit 12 can inject resin at a low pressure. Then, by finely adjusting (readjusting) the injection conditions of each injection unit 12 within the injection condition range for low-pressure injection, the injection units 12 are arranged in a 2 × 3 grid.

As shown in FIGS. 1 and 2, the mold clamping device 8 includes a plurality of tie bars 38 fixed to the upper platen 6 and a hydraulic cylinder 40 that moves the lower platen 4 up and down. The tie bars 38 are arranged along the vertical direction, and the lower platen 4 is guided by these tie bars 38.
The hydraulic cylinder 40 is installed below the lower platen 4, and when the hydraulic cylinder 40 pushes the lower platen 4 upward, the lower platen 4 moves so as to be close to the upper platen 6 while being guided by the tie bar 38. To do. Accordingly, the mold clamping device 8 performs mold clamping of the fixed mold 14 held by the upper platen 6 and the movable mold 16 held by the lower platen 4.

The operation of the injection molding apparatus 1 configured as described above will be described.
First, each injection unit 12 is installed in the attachment port 20, and the injection port 22 of the plunger 24 is communicated with the resin injection port 18. Further, the fixed mold 14 and the movable mold 16 are clamped with a predetermined mold clamping pressure by the mold clamping device 8 to form the cavity 10 inside the mold 2.
In the present embodiment, the same resin material is supplied to the material supplier 26 of each injection unit 12, and this resin material is supplied into the cylinder 30 of the plunger 24. The resin material supplied to the cylinder 30 is heated by the heater 28 and is kneaded and plasticized while being transferred by the screw 32.

  When the servo motor 36 of each injection unit 12 is rotated to move the screw 32 upward, the plasticized resin material is supplied to the space between the cylinder 32 and the screw 32 tip. Thereafter, when each screw 32 is moved downward, the resin material is pushed into the cavity 10 from the injection port 22 by the screw 32. At this time, the injection speed of the screw 32 is set so that the resin material in the cavity 10 is pushed and moved by the resin material supplied later and is supplied at a pressure that does not apply a large pressure to the resin. Yes. The injection pressure applied to the resin material at the time of injection is much lower than that of a conventional injection molding apparatus.

  Here, as described above, the injection conditions of the resin from each injection unit 12 may all be the same, or may be different within a predetermined injection condition range. For example, in addition to the above-described injection amount and injection pressure, the injection timing of each injection unit 12 may be the same or may be different within a predetermined injection condition range. Specifically, the injection unit 12 in charge of the injection region 23 that takes time to spread the resin to every corner of the injection region 23 is preceded by a timing earlier than the injection timing of the resin from the other injection units 12. The time for injecting and spreading the resin to the injection region 23 may be saved. In this case, the injection timing is set so that the resin from the adjacent injection unit 12 can be combined before the resin at the outer edge is solidified.

  The resin material injected into the cavity 10 from the injection port 22 proceeds through the cavity 10 mainly by its viscosity and spreads into the cavity 10 while being pushed out by the resin material further supplied from the injection port 22. The resin material injected from one injection port 22 travels through the cavity 10, fills the injection region 23, respectively, and contacts and bonds with the resin material injected from the adjacent injection port 22.

  After injecting the resin material, the mold 2 is cooled by the cooling means 44, and the resin material in the cavity 10 is solidified to form a molded product. After the resin material is solidified, the movable mold 16 is moved downward relative to the fixed mold 14 by the mold clamping device 8 to open the mold, and the molded product is taken out from the mold 2.

According to this embodiment having such a configuration, the following excellent effects can be obtained.
Since a plurality of injection units 12 are used to inject resin from a plurality of injection ports 22 into one cavity 10, the region in the cavity 10 into which one injection unit 12 is injected can be divided into small portions. Therefore, even if each injection unit 12 injects the resin material at a lower injection pressure (injection speed) than before, the injection material 12 can be distributed to the outer edge of the injection region 23 that each injection unit 12 takes over. The injection pressure of the entire apparatus 1 can be lowered.
In the conventional injection molding apparatus that injects from one injection port, when the molded product is large, a very large injection pressure is required to spread the resin material to the outer edge of the cavity. According to the injection molding apparatus, a good molded product can be obtained with a low injection pressure even in such a case. Moreover, since the injection pressure required for the injection unit 12 is low, the structure of the injection unit 12 can be simplified, and the miniaturization of the injection unit 12 can be promoted.

  Since the injection pressure of the injection unit 12 can be reduced, the mold clamping pressure by the mold clamping device 8 can also be reduced. Therefore, since the pressure required for the hydraulic cylinder 40 of the mold clamping device 8 can be low, the structure of the mold clamping device 8 can be simplified, and the size reduction of the mold clamping device 8 can be promoted.

  Since the injection region 23 of the cavity 10 is set according to the injection conditions of the injection unit 12 and the injection unit 12 is arranged for each injection region 23, the entire cavity 10 can be injected even if resin is injected from each injection unit 12 at a low pressure. Can spread resin. In particular, when the cavity 10 has an elongated molded part or a fine molded part, the conventional injection molding apparatus needs to inject the resin at a higher pressure in order to spread the resin to such a molded part. was there. On the other hand, in the injection molding apparatus 1 of the present invention, since the injection region 23 is set in consideration of the injection conditions of each injection unit 12, the region in the cavity 10 where each injection unit 12 must inject resin. Can be set smaller than in the prior art, and the cavity 10 having various shapes and sizes can be injected at a low pressure. Thereby, a good molded product can be obtained while achieving simplification of the structure of the mold 2 and the mold clamping device 8.

  Since the injection pressure of the injection unit 12 and the mold clamping pressure of the mold clamping device 8 can be reduced, the strength required for the mold 2 can be reduced. Therefore, the mold 2 can be made thinner, and cost saving and space saving can be promoted. Moreover, since the mold 2 can be further reduced in size, the cutting work of the mold 2 is facilitated, and the mold 2 can be created in a short period of time. As a result, for example, even in the case of multi-product small-volume production such as molding of a prototype, it is possible to quickly and flexibly cope with molded products of various shapes.

  Since each injection unit 12 includes an independent and separate material supply machine 26 and a heater 28, the same or different materials are supplied to each material supply machine 26 from each injection unit 12 to one cavity 10. The same or different materials can be injected in various combinations. Therefore, for example, flexible injection molding conditions such as supplying materials having different colors to different portions of the cavity 10 or supplying materials having different material properties such as strength can be set. Thereby, various kinds of molded products can be manufactured.

  Since the control means 42 controls the servo motor 36 and the heater 28 of each injection unit 12 independently, the injection conditions such as the injection amount, injection speed, and injection amount from each injection port 22 are set independently. can do. Therefore, for example, even when the shape of the cavity 10 is irregular, it is possible to perform control such that only one injection unit 12 is injected more slowly or faster than other injection units 12 within a predetermined injection condition range. . Therefore, molded products having more various shapes can be formed.

[Second Embodiment]
Next, the injection molding apparatus of 2nd Embodiment of this invention is demonstrated. The injection molding apparatus of the second embodiment is different from the injection molding apparatus of the first embodiment in that a resin material is injected into a mold in which a plurality of cavities are formed.

  FIG. 6 is an overall perspective view of an injection molding apparatus 50 according to the second embodiment of the present invention. FIG. 7 shows the arrangement of the injection ports 52 of the injection molding apparatus 50 according to the second embodiment of the present invention. As shown in FIGS. 6 and 7, the injection ports 52 of the injection molding apparatus 50 of the present embodiment are arranged in a grid pattern at equal intervals. In the present embodiment, eight injection ports 52 are arranged in 2 rows and 4 columns.

  A plurality of cavities 56, 57, 58 are formed in the mold 54. These cavities 56, 57, and 58 are formed in different shapes and sizes. Two injection ports 52 are arranged in the cavity 56, one injection port 52 is arranged in the cavity 57, and three injection ports 52 are arranged in the cavity 58. Further, two of the eight injection ports 52 do not communicate with any cavity.

  Each injection unit 12 is provided with an injection region 59 to be covered by the injection unit 12 as represented by a dotted line in FIG. These injection regions 59 are set in consideration of the shapes of the cavities 56, 57, 58 according to the injection conditions of the injection unit 12, and the volume of the cavities 56, 57, 58 and the area of the mold 54 in plan view, It is preferable to determine according to the complexity of the shape of the cavities 56, 57, and 58.

In the injection molding apparatus 50 having such a configuration, the resin material is injected from each injection unit 12 into the corresponding cavities 56, 57, and 58 at a predetermined speed. At this time, the injection speed of the resin material is set to such a speed that the resin injected into the cavities 56, 57, and 58 spreads into the cavities 56, 57, and 58 so as to be pushed out into the resin that is subsequently injected. Has been. Resin material is injected into the cavity 56 from two injection ports 52, the cavity 57 from one injection port 52, and the cavity 58 from three injection ports 52. At this time, since the resin material is injected into the cavities 56 and 58 from the plurality of injection ports 52, the resin material injected from each of the injection ports 52 spreads toward the outer edge of the injection region 59 and is adjacent to the injection beam. The resin material injected from the outlet 52 is brought into contact with and bonded. The cavity 57 is filled with a resin material injected from one injection port 52.
The resin material is not injected from the injection unit 12 disposed in the injection port 52 that does not communicate with the cavities 56, 57, and 58.

According to the above embodiment, in addition to the same effect as that of the first embodiment, the following effect can be obtained.
That is, the injection units 12 are arranged in a grid at predetermined intervals, and the resin material is injected from the injection unit 12 selected according to the shape, arrangement, etc. of the cavities 56, 57, 58 formed in the mold 54. Therefore, the resin material can be filled into the cavity having an arbitrary shape. In addition, since the injection unit 12 that injects the resin material can be selected in accordance with the shape of the cavities 56, 57, and 58, the degree of freedom of arrangement of the cavities 56, 57, and 58 in the mold 54 is increased. A plurality of cavities 56, 57, 58 can be efficiently arranged in the mold 54.

  Since the injection operation of each injection unit 12 can be controlled independently, it can be controlled not to inject the injection unit 12 located in the portion where the cavities 56, 57, 58 of the mold 54 are not formed. Accordingly, since the resin material can be injected into the cavities 56, 57, and 58 having various shapes and arrangements without changing the arrangement of the injection unit 12, it is possible to flexibly handle molding of various shapes of molded products. be able to.

  Since the material feeder 26 and the heater 28 are provided in each injection unit 12, it is also possible to supply different resin materials to the cavities 56, 57, and 58, respectively. Therefore, molded products having different shapes can be obtained from different materials in a single molding process, and various molded products can be molded.

  The present invention is not limited to the above-described embodiment. For example, the injection of the resin material from a plurality of injection units may be performed simultaneously, or may be performed sequentially from adjacent injection ports at different timings. . That is, for example, in the first embodiment described above, the resin material is injected from the two end injection units 12 out of the six injection units 12, and after a predetermined time has passed, the two adjacent injection units 12, that is, the center. The resin material may be injected from the two injection units 12, and after a predetermined time has passed, the resin material may be injected from two adjacent injection units 12, that is, the two injection units 12 at the opposite ends.

  Alternatively, the resin material may be injected from the four injection units 12 at both ends, and after a predetermined time has elapsed, the resin material may be injected from the two central injection units 12 adjacent to them. Further, the resin material is injected from one or two injection units 12 in the center, and after a predetermined time has elapsed, the resin material is sequentially injected from one or a plurality of injection units 12 adjacent thereto. Good.

  According to such an injection molding method, the injection timing of the resin material from each injection unit 12 is shifted, so that the injection pressure applied to the mold 2 can be further reduced. Therefore, the mold clamping pressure of the mold 2 by the mold clamping device 8 can be further reduced. Therefore, simplification, cost saving, and miniaturization of the structure of the mold clamping device 8 can be further promoted. Further, if the resin is sequentially injected into the cavity 10 from the adjacent injection units 12, the flow of the resin in the cavity 10 is stabilized, and the gas or air in the cavity 10 is easily released, so that a good molded product can be obtained. it can.

  The number of plungers may not be the same as the number of injection ports. For example, more plungers may be provided than the number of injection ports, and a necessary plunger may be installed at a predetermined injection port to inject the resin material. Alternatively, the number of plungers may be less than the number of injection ports, and the resin material may be sequentially injected while moving with respect to the plurality of injection ports.

The plurality of injection ports are not limited to those arranged at regular intervals along the length direction and width direction of the mold, but are arbitrarily selected according to the shape range of the molded product handled by the injection molding apparatus Can be set to Therefore, the injection port may be arranged at random.
FIG. 8 is a view showing a modification of the arrangement of the injection units according to the present invention. An irregularly shaped cavity 62 is formed in the mold 60. As shown in FIG. 8, the injection region 66 of the cavity 62 is assigned to each injection unit so that the resin can be distributed into the cavity 62 under the injection conditions of the injection unit. Therefore, a relatively small injection region 66 is set in a region where the elongated molded portion of the cavity 62 is present. One injection port 64 of the injection unit is arranged for each of these injection regions 66. Thus, depending on the injection conditions of the injection unit and the shape of the cavity 62, the injection ports 64 may not be spaced apart from each other and may be arranged randomly.

  In the above-described embodiment, the injection molding apparatus is a vertical injection molding apparatus in which the movable mold moves up and down with respect to the fixed mold. However, in the present invention, the movable mold is lateral (horizontal) with respect to the fixed mold. It can also be applied to a horizontal injection molding apparatus that moves to).

1 is an overall perspective view showing an injection molding apparatus according to a first embodiment of the present invention. It is sectional drawing which shows the part of the metal mold | die of the injection molding apparatus by 1st Embodiment of this invention. It is a partial sectional side view which shows the injection unit by 1st Embodiment of this invention. 1 is a block diagram of an injection molding apparatus according to a first embodiment of the present invention. It is a figure which shows the injection area | region of the injection molding apparatus by 1st Embodiment of this invention. It is a whole perspective view which shows the injection molding apparatus by 2nd Embodiment of this invention. It is a figure which shows the injection | emission area | region of the injection unit by 2nd Embodiment of this invention. It is a figure which shows the modification of arrangement | positioning of the injection unit by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,50 Injection molding apparatus 2,54 Mold 8 Clamping apparatus 10,56,57,58 Cavity 12 Injection unit 22,52 Injection port 23,59 Injection area 24 Plunger 26 Material supply machine 28 Heater 42 Control means

Claims (4)

An injection molding apparatus for injecting resin into a cavity of a mold having a plurality of resin injection ports,
Multiple injection units;
A plurality of injection ports for communicating each of the injection units with the different resin injection ports of the cavity,
Each of the injection units has a plunger, a material supply means for supplying a resin material to the plunger, and a plasticizing means for plasticizing the resin in the plunger.
An injection molding apparatus characterized by that. An injection molding apparatus for injecting resin into a cavity of a mold having a plurality of resin injection ports,
Multiple injection units;
A plurality of injection ports for communicating each of the injection units with the different resin injection ports of the cavity,
Each injection unit has a plunger, a material supply means for supplying a resin material to the plunger, and a plasticizing means for plasticizing the resin in the plunger,
The cavity is assigned to each injection unit as a region where each injection unit can spread resin, and the injection unit is arranged for each assigned region,
An injection molding apparatus characterized by that. Each of the plungers is configured to sequentially inject resin into the cavity by shifting the injection timing.
The injection molding apparatus according to claim 1 or 2. The plurality of injection ports are arranged in a lattice pattern,
Each plunger is configured to selectively inject a resin according to the shape of the cavity.
The injection molding apparatus according to any one of claims 1 to 3.

Images