JP2007118233A - Nozzle for injection molding machine and injection molding method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle for an injection molding machine for performing multiple-material molding which first forming a sandwich molded part having a skin layer and a core layer using three kinds of resins and two nozzle tips and subsequently further joining a third resin on the sandwich molded part integrally. <P>SOLUTION: Three ports, three flow channels and two nozzle tips are provided to the nozzle 10. The first flow channel 31 starts from the hole-like flow channel continued to the first port 21 and becomes an annular flow channels 31a passing the periphery of a core 41 to be connected to the flow channel 15 in the first nozzle tip 11 and the second first flow channel 32 is the hole like flow channel parallel to the center axis of the nozzle 10 to connect the second part 22 and the flow channel 16 in the second nozzle tip 12 while the third flow channel 33 is the flow channel obliquely extending from the third port 23 to be connected to the flow channel 15 in the first nozzle tip through the interior of the core 41. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a nozzle for an injection molding machine used for multi-material molding, and in particular, a sandwich molding part comprising a skin layer and a core layer is formed, and then a third resin is joined thereon to form an integral part. The present invention relates to a nozzle for an injection molding machine used for multi-material molding as a molded product. The invention also relates to an injection molding method using such a nozzle.

  A technique of performing sandwich molding using two kinds of resins to form a skin layer and a core layer and a technique of performing two-color or two-material molding using two kinds of resins are already known.

  The mold used in this two-color or two-material molding is different in the volume of the mold cavity when injecting the first resin and the second resin, and the sprue that injects the resin into the mold cavity. The gate position is also different. That is, after the first resin is injected from the first sprue and gate to the mold cavity, the mold cavity is enlarged, and the second resin is injected from the second sprue and gate. Therefore, in order to perform two-color or two-material molding, an injection unit having two nozzle chips is necessary, which is also a known technique.

  Also, a technique for selecting and molding sandwich molding and two-color or two-material molding using two kinds of resins and two nozzle chips is also known. However, using three kinds of resins and two nozzle tips, first, a sandwich molding part having a skin layer and a core layer is formed, and then a third resin is used in the sandwich molding part. A technique for multi-material molding in which the layers are integrally joined is not yet known.

  FIG. 5 shows a structure described in Japanese Patent Application Laid-Open No. 07-227878 as an example of a conventional nozzle for an injection molding machine (Patent Document 1). This nozzle is used when performing injection molding using two types of resins, and is configured to be able to select and switch between sandwich molding and two-color or two-material molding.

  That is, the nozzle includes a merging nozzle 83 and a nozzle 84 and is connected to the first injection unit 81 and the second injection unit 82. The joining nozzle 83 is configured to perform sandwich molding by joining the resins supplied from the first injection unit 81 and the second injection unit 82. The nozzle 84 is used when only the resin from the second injection unit 82 is injected alone. The switching valve 85 is used to switch whether the resin sent from the second injection unit 82 is sent to the merging nozzle 83 or the nozzle 84. When switching to the merging nozzle 83 side, sandwich molding is performed using the resin from the first injection unit 81 as a skin layer and the resin from the second injection unit 82 as a core layer. When switching to the nozzle 84 side, the resin sent from the second injection unit 82 is injected from the nozzle 84, and only the resin sent from the first injection unit 81 is injected from the merge nozzle 83, and two-color or two-material molding is performed. Done.

That is, this nozzle is formed by selecting either sandwich molding, two-color molding or two-material molding. The two nozzles 83 and 84 are used simultaneously or sequentially, and are first composed of a skin layer and a core layer. It is not possible to perform a multi-material molding in which a sandwich molding part is formed and then a third resin is joined and integrated thereon.
Japanese Patent Application Laid-Open No. 07-227878

  As described above, using three types of resin and two nozzle tips, first, a sandwich molded part having a skin layer and a core layer is formed, and then a third resin is joined to the sandwich molded part. The technology for multi-material molding that integrates with each other is not yet known. An object of the present invention is to provide an injection molding machine nozzle for enabling such multi-material molding, and an injection molding method using such an injection molding machine nozzle.

The nozzle for an injection molding machine of the present invention is
A nozzle for an injection molding machine used for multi-material molding, in which a sandwich molded part composed of a skin layer and a core layer is formed, and then a third resin is joined thereon to form an integral molded product,
A first nozzle chip and a second nozzle chip connected to the mold;
A first port for receiving resin from the first injection unit;
A second port for receiving resin from the second injection unit;
A third port for receiving resin from the third injection unit;
A first flow path connecting the first port and the first nozzle tip;
A second flow path connecting the second port and the second nozzle tip;
A third flow path connecting the third port and the first nozzle tip, and joining the first flow path inside the first nozzle tip;
It is provided with.

In this injection molding machine nozzle, preferably,
The first flow path becomes a hole-shaped flow path parallel to the central axis of the nozzle for the injection molding machine at the upstream end and is connected to the first port. At the downstream end, the first flow path is an annular shape surrounding the central axis of the hole-shaped flow path. It becomes a flow path, connected to the flow path in the first nozzle tip,
The second flow path is a hole-shaped flow path parallel to the central axis of the injection molding machine nozzle at the upstream end and is connected to the second port, and the downstream end is parallel to the central axis of the injection molding machine nozzle. It remains connected to the flow path in the second nozzle chip while remaining a hole-shaped flow path.
The third flow path is a hole-shaped flow path that extends from the third port to an extension line of the central axis of the first nozzle tip and then passes over the central axis of the first nozzle chip, and the first nozzle It is comprised so that it may merge with said 1st flow path inside a chip | tip.

  Using the nozzle for an injection molding machine, for example, multi-material molding can be performed by the following procedure.

  First, the first injection unit is activated, and skin resin is supplied from the first port into the mold through the first flow path and the first nozzle tip in this order. After the skin resin is supplied in a predetermined amount, the third injection unit is activated, and the core resin is supplied from the third port through the first nozzle chip into the mold, and Stop supplying the skin resin from the first injection unit. After the core resin is supplied in a preset amount, the supply of the skin resin from the first injection unit is resumed and the supply of the core resin from the third injection unit is stopped. After the skin resin is supplied in a predetermined amount, the supply of the skin resin from the first injection unit is stopped. After the elapse of a preset time, the second injection unit is activated to supply the third resin from the second port to the mold through the second flow path and the second nozzle tip in this order. After the elapse of a preset time, the supply of the third resin from the second injection unit is stopped and the injection process is terminated.

  As a modification of the above method, the skin resin may be continuously supplied when the core resin is supplied into the mold in an intermediate stage of the process.

  By using the nozzle for an injection molding machine of the present invention, first, a sandwich molding part having a skin layer and a core layer is formed using three kinds of resins and two nozzle tips, and then this sandwich Multi-material molding can be realized in which the third resin is joined and integrated with the molding part.

  Sandwich molding is used as a technique for realizing various functions such as surface quality improvement, surface strengthening, weight reduction, and reuse of waste resin, depending on the combination of resins used, but the apparatus and method of the present invention. By using multi-material molding that additionally joins a third resin onto the sandwich molding part, the bottom part of the sandwich molded product is given a non-slip function, or a seal function part is given around the part. For example, it is possible to further enhance the functionality of the sandwich molded product.

  In FIG. 1, the example of the nozzle for injection molding machines of this invention is shown. FIG. 2 shows a state in which this nozzle is connected to three injection units. In the figure, 10 is a nozzle, 11 is a first nozzle tip, 12 is a second nozzle tip, 21 is a first port, 22 is a second port, 23 is a third port, 31 is a first flow path, and 32 is a second flow. Road, 33 is a third flow path, 51 is a first injection unit, 52 is a second injection unit, and 53 is a third injection unit.

  As shown in FIG. 1, the main part of the nozzle 10 includes a nozzle body 13, two nozzle chips (first nozzle chip 11 and second nozzle chip 12), and a connection ring 14. The connection ring 14 is provided with three ports (first port 21, second port 22, and third port 23) for receiving three types of resins sent from the three injection units. In the nozzle body 13, three flow paths, that is, a first flow path 31, a second flow path 32, and a third flow path 33 are formed. The first nozzle tip 11 and the second nozzle tip 12 are each connected to a sprue provided on the back surface of the mold.

  The first flow path 31 is a flow path parallel to the central axis of the nozzle 10, and connects the first port 21 and the flow path 15 in the first nozzle chip 11. The second flow path 32 is a flow path parallel to the central axis of the nozzle 10, and connects between the second port 22 and the flow path 16 in the second nozzle chip 12. The central axes of the first nozzle chip 11 and the second nozzle chip 12 coincide with the central axes of the first flow path 31 and the second flow path 32, respectively. The third flow path 33 extends obliquely from the third port 23 and is connected to the flow path 15 in the first nozzle chip through the inside of the core 41 (described later).

  A core 41 is attached inside the first flow path 31, and the central axis of the core 41 coincides with the central axis of the first flow path 31. The front end (left end in the figure) of the core 41 protrudes into the flow path 15 in the first nozzle chip, and the rear end of the core 41 is located in the middle of the first flow path 31. Inside the core 41, a flow path starting from the side surface and passing through the central axis of the core and opening at the tip is formed.

  As described above, the first flow path 31 starts from the hole-shaped flow path that follows the first port 21 and becomes an annular flow path 31 a that passes around the core 41, thereby forming the flow path 15 inside the first nozzle chip 11. Connected to. The third channel 33 passes through a hole-like channel extending obliquely from the third port 23, enters the inside from the side surface of the core 41, and becomes a hole-like channel 33 a that passes on the central axis of the core 41. The first nozzle tip 11 is connected to the flow path 15.

  As shown in FIG. 2, the nozzle 10 is connected to three injection units (a first injection unit 51, a second injection unit 52, and a third injection unit 53) via a connection block 60. On / off valves 54, 55, and 56 are provided at the injection ports 57, 58, and 59 of the first injection unit 51, the second injection unit 52, and the third injection unit 53, respectively. Inside the connection block 60, flow paths are formed that connect the respective injection ports 57, 58, 59 to the first port 21, the second port 22, and the third port 23.

  Next, a procedure for forming a multi-material by first forming a sandwich molding part and then integrally joining a third resin thereon using the nozzle for an injection molding machine shown in FIGS. 1 and 2 will be described. . The mold used has a mechanism that allows the volume of the mold cavity to be changed during sandwich molding and when the third resin is integrally joined to the sandwich molded part.

  Molding begins with the mold cavity volume set for sandwich molding. First, the on-off valve 54 is opened, the first injection unit 51 is activated, and the skin resin is supplied to the nozzle 10. The skin resin sent from the first injection unit 51 passes through the first flow path 31 from the first port 21, enters the flow path 15 in the first nozzle chip 11 from the outer peripheral flow path 31a of the core 41, and passes through the first flow path 31. It is injected from the nozzle tip 11 into the mold. The surface of the injected resin is cooled in the mold cavity to form a skin layer.

  After a predetermined amount of resin is supplied from the first injection unit 51, the first injection unit 51 is stopped (or remains activated), the on-off valve 56 is opened, and the third injection unit 53 is started to supply the core resin to the nozzle 10. The core resin sent from the third injection unit 53 flows into the third flow path 33 from the third port 23, and flows from the flow path 33 a on the central axis of the core 41 to the flow path 15 in the first nozzle chip 11. It enters and is injected from the first nozzle tip 11 into the mold. This core resin flows into the mold while excluding the skin resin remaining in the flow path 15, and is already solidified after the surface has been cooled and solidified in the cavity of the mold. It flows through the inside, which is still in a molten state, and forms a core layer.

  After a predetermined amount of core resin is supplied from the third injection unit 53, the third injection unit 53 is stopped and the on-off valve 56 is closed. The first injection unit 51 is restarted (or left activated), the skin resin is supplied from the first nozzle chip 11 into the mold, and the skin resin is caused to flow so as to wrap the core resin. The sandwich molding with the skin resin covered is completed.

  Next, the volume of the mold cavity is enlarged and changed to a molding process in which the third resin is integrally joined to the sandwich molding part.

  After the completion of the sandwich molding, after a preset time has elapsed, the on-off valve 55 is opened, the second injection unit 52 is activated, and the third resin is supplied to the nozzle 10. The third resin sent from the second injection unit 52 flows into the second flow path 32 from the second port 22, enters the flow path 16 in the second nozzle chip 12, and molds from the second nozzle chip 12. It is injected in. After a preset amount of the third resin is supplied into the mold, the entire injection process of the multi-material molding is completed after a preset time has elapsed.

  FIG. 3 and FIG. 4 show an example of the relationship between the nozzle and the state in the mold when multi-material molding is performed using the injection molding machine nozzle shown in FIG. 1 and FIG.

  This metal mold is composed of a male mold 71 used in common and two types of female molds (first female mold 72 and second female mold 75) having different depths. The first female mold 72 and the second female mold 75 are moved by a slide mechanism (not shown), and either one is combined with the male mold 71 to form mold cavities having different volumes. Yes. The first female die 72 has a first sprue 73 and a first gate 74, and the second female die 75 has a second sprue 76 and a second gate 77.

  FIG. 3 corresponds to the case where sandwich molding is first performed, and a male die 71 is combined with a first female die 72 having a shallow depth. At this time, the first sprue 73 of the first female die 72 is in a positional relationship to be connected to the nozzle tip 11, and the skin resin and the core resin injected from the nozzle tip 11 are transferred from the first sprue 73 to the first gate. After 74, it flows into the mold cavity and sandwich molding is performed.

  When the sandwich molding is completed, the mold is opened, and the male mold 71 is retracted integrally with the sandwich molded product in close contact therewith. Thereafter, the female mold side is moved by a slide mechanism (not shown), and reaches the position where the second female mold 75 is combined with the male mold 71, and the mold is closed (FIG. 4). By closing the mold, the mold cavity is in a state in which a space 75a for the third resin is left as a space. In this space, the third resin is injected from the nozzle tip 12 and flows into the mold cavity from the second sprue 76 through the second gate 77, and the third resin is joined to the sandwich molding part and integrally molded. Is done.

  The method of expanding and changing the volume of the mold cavity by sandwich molding and subsequent integral molding of the third resin is a part of the mold by generally known rotation and sliding in addition to this example. It is also possible to enlarge the image partially. The necessary condition is that a mold cavity enlarged from the time of sandwich molding can be configured, and a flow path is formed in the expanded cavity space so that resin flows from a sprue different from that at the time of sandwich molding. .

It is sectional drawing which shows an example of the nozzle for injection molding machines based on this invention. It is a schematic block diagram which shows the state which connected the nozzle for injection molding machines based on this invention to three injection units. It is a figure which shows the relationship between a nozzle and the state in a metal mold | die at the time of performing multi-material shaping | molding using the nozzle for injection molding machines based on this invention, Comprising: The stage of the first sandwich molding is represented. It is a figure which shows the relationship between the state in a nozzle and a metal mold | die at the time of performing multi-material molding using the nozzle for injection molding machines based on this invention, Comprising: 3rd resin is integrally joined to a sandwich molding part Represents the stage to do. It is sectional drawing which shows an example of the nozzle for conventional injection molding machines.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Nozzle, 11 ... First nozzle tip, 12 ... Second nozzle tip, 13 ... Nozzle body, 14 ... Connection ring, 15, 16 ... Channel, 21 ... First port, 22 ... Second port, 23 ... First Three ports, 31 ... first flow path, 31a ... annular flow path, 32 ... second flow path, 33 ... third flow path, 33a ... porous flow path, 41 ... core, 51 ... first injection unit, 52 ... first Two injection units, 53 ... third injection unit, 54, 55, 56 ... on-off valve, 57, 58, 59 ... injection port, 60 ... connection block, 71 ... male type, 72 ... first female type, 73 ... first Sprue 74 ... first gate 75 ... second female type 76 ... second sprue 77 ... first gate 81 ... first injection unit 82 ... second injection unit 83 ... merge nozzle 84 ... nozzle 85: Switching valve.

Claims (4)

A nozzle for an injection molding machine used for multi-material molding, in which a sandwich molded part composed of a skin layer and a core layer is formed, and then a third resin is joined thereon to form an integral molded product,
A first nozzle chip and a second nozzle chip connected to the mold;
A first port for receiving resin from the first injection unit;
A second port for receiving resin from the second injection unit;
A third port for receiving resin from the third injection unit;
A first flow path connecting the first port and the first nozzle tip;
A second flow path connecting the second port and the second nozzle tip;
A third flow path connecting the third port and the first nozzle tip, and joining the first flow path inside the first nozzle tip;
A nozzle for an injection molding machine. The first flow path becomes a hole-shaped flow path parallel to the central axis of the nozzle for the injection molding machine at the upstream end and is connected to the first port. At the downstream end, the first flow path is an annular shape surrounding the central axis of the hole-shaped flow path. It becomes a flow path, connected to the flow path in the first nozzle tip,
The second flow path is a hole-shaped flow path parallel to the central axis of the injection molding machine nozzle at the upstream end and is connected to the second port, and the downstream end is parallel to the central axis of the injection molding machine nozzle. It remains connected to the flow path in the second nozzle chip while remaining a hole-shaped flow path.
The third flow path is a hole-shaped flow path that extends from the third port to an extension line of the central axis of the first nozzle tip and then passes over the central axis of the first nozzle chip, and the first nozzle Merging with the first flow path inside the chip,
The nozzle for an injection molding machine according to claim. An injection molding method for performing multi-material molding using the nozzle for an injection molding machine according to claim 2,
Start up the first injection unit, and supply the resin for skin from the first port through the first flow path and the first nozzle tip in this order,
After the skin resin is supplied in a predetermined amount, the third injection unit is activated, and the core resin is supplied from the third port through the first nozzle chip into the mold, and Stop supplying skin resin from the first injection unit,
After the core resin is supplied in a predetermined amount, the supply of the skin resin from the first injection unit is resumed, and the supply of the core resin from the third injection unit is stopped,
After the skin resin is supplied in a preset amount, the supply of the skin resin from the first injection unit is stopped,
After elapse of a preset time, start the second injection unit, supply the third resin from the second port through the second flow path, the second nozzle tip in order, into the mold,
An injection molding method characterized in that after a preset time has elapsed, the supply of the third resin from the second injection unit is stopped and the injection process is terminated. An injection molding method for performing multi-material molding using the nozzle for an injection molding machine according to claim 2,
Start up the first injection unit, and supply the resin for skin from the first port through the first flow path and the first nozzle tip in this order,
After the skin resin is supplied in a predetermined amount, the third injection unit is started while continuing to supply the skin resin from the first injection unit, and the core resin is supplied to the third port. From the first nozzle tip through the mold,
After the core resin is supplied in a preset amount, the supply of the core resin from the third injection unit is stopped while continuing to supply the skin resin from the first injection unit,
After the skin resin is supplied in a preset amount, the supply of the skin resin from the first injection unit is stopped,
After elapse of a preset time, start the second injection unit, supply the third resin from the second port through the second flow path, the second nozzle tip in order, into the mold,
An injection molding method characterized in that after a preset time has elapsed, the supply of the third resin from the second injection unit is stopped and the injection process is terminated.

Images