JP2009226936A - Injection molding nozzle, injection molding apparatus, injection-molded product, and method of injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding nozzle, an injection molding apparatus, and a method of injection molding which can efficiently vibrate melted resin in injection molding, and also to provide an injection-molded product. <P>SOLUTION: The injection molding nozzle includes a channel through which the melted resin 7 filled from a resin filling port 11 flows, an injection port 16 for injecting this melted resin 7 to a mold, an opening and closing pin 4 for opening and closing the injection port by advancing and retreating the pin in an axial direction, a vibrator 2 fixed to this opening and closing pin 4 to oscillate an ultrasonic wave, and an opening and closing pin drive actuator 12 for advancing and retreating the opening and closing pin. The melted resin is vibrated through the opening and closing pin 4 by the ultrasonic wave oscillated from this vibrator 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injection molding nozzle, an injection molding machine, an injection molded product, and an injection molding method.

  Conventionally, when high-precision resin molding is performed, there is a problem that a resin is not sufficiently filled in a mold, and it is difficult to obtain necessary molding accuracy. FIG. 5 is a partial cross-sectional view showing a conventional injection molding machine together with a part of a mold. In the injection molding machine shown in FIG. 5, a screw is rotatably attached to the flow path of the injection nozzle 1. The injection nozzle 1 is fixed to the fixed mold 5 by a nozzle fixing plate 3. The nozzle tip 15 is connected to the cavity 8 which is a recess of the movable mold 6 so that the molten resin 7 can be injected. The vibrator 2 that generates ultrasonic waves is fixed to the side surface of the injection nozzle 1.

  In the injection molding machine of FIG. 5, the pellet-shaped molding resin filled from the material inlet (not shown) on the right side of the figure is moved through the injection nozzle 1 by the rotation of the screw 14. It is sent to the side space and heated and melted in the process. Along with this, the screw 14 is moved to the right side of the drawing, and the molten resin 7 is filled into the cavity 8 through the gate 9. After the resin is melted, the vibrator 2 vibrates the injection nozzle 1 and the vicinity thereof. The vibration of the nozzle causes the molten resin in the flow path to vibrate through the vibration of the injection nozzle. In this manner, ultrasonic waves can be propagated from the outside of the injection nozzle to the molten resin through the injection nozzle, the frictional force between the molten resin and the injection nozzle can be reduced, and the apparent fluidity of the molten resin can be increased. (For example, refer to Patent Document 1).

JP 2002-370255 A

  However, in the method of applying vibration to the nozzle, since the outer peripheral surface of the injection nozzle 1 is vibrated, the efficiency of transmitting vibration to the molten resin flowing inside the nozzle inner surface and inside the nozzle is poor.

  The present invention has been made in view of such circumstances, and an object thereof is to efficiently vibrate the molten resin.

  An injection molding nozzle according to the present invention opens and closes the injection port by advancing and retreating in the axial direction, a flow path through which the molten resin injected from the resin injection port flows, an injection port for injecting the molten resin into a mold, and An open / close pin, an oscillator fixed to the open / close pin and oscillating ultrasonic waves, and an open / close pin drive actuator for moving the open / close pin forward and backward, and the ultrasonic wave oscillated from the vibrator passes through the open / close pin. The molten resin is vibrated.

  With such a feature, the vibrator vibrates the molten resin through the open / close pin, and therefore the molten resin can be efficiently vibrated.

  It is preferable that the vibrator of the injection molding nozzle according to the present invention is fixed to an end portion of the open / close pin facing the injection port.

With such a feature, the vibrator can be efficiently arranged inside the injection molding machine, and the injection molding machine can be configured in a small size.
In the injection molding nozzle according to the present invention, it is preferable that the open / close pin penetrates to the outside of the flow path.

With such a feature, the opening / closing pin 4 can be vibrated more stably than when operated inside a resin melted at a high temperature, and high-precision molding can be performed.
The opening / closing pin drive actuator of the injection molding nozzle according to the present invention is preferably disposed on an end surface of the injection nozzle facing the injection port.
With such a feature, since the shaft, the vibrator, and the open / close pin are arranged in a straight line, the open / close pin can be efficiently advanced and retracted.

  The frequency of the ultrasonic wave oscillated by the vibrator according to the present invention is preferably such that the resonance node is the same as the position of the cavity of the mold.

  With such a feature, the molten resin inside the cavity can be vibrated efficiently.

  The injection molding nozzle according to the present invention preferably has a nozzle fixing plate for fixing the side surface of the injection nozzle and the mold.

  With such a feature, the injection nozzle can be stably fixed to the stationary mold.

  The injection molding machine according to the present invention preferably includes a vibration isolating plate 17 between the nozzle fixing plate and the mold.

  With such a feature, it is possible to efficiently suppress the vibration of the entire injection molding machine without suppressing the vibration of the molten resin.

  An injection molding method according to the present invention includes a step of injecting a molten resin from a resin injection port provided in an injection nozzle, and an ultrasonic wave oscillated by a vibrator that opens and closes the molten resin via an opening / closing pin that opens and closes the injection port. The method includes a step of vibrating and an injection step of injecting the molten resin from an injection port.

  Due to such characteristics, the molten resin can be efficiently vibrated and injected into the cavity.

  In the injection molding method according to the present invention, after the injection step, a step of closing the injection port by the opening / closing pin and a post-injection vibration step of vibrating the opening / closing pin by a vibrator even after the injection port is closed are provided. It is characterized by having.

  Due to such characteristics, vibration is also transmitted to the resin inside the mold, and a highly accurate molded product can be obtained.

  In the post-injection molding step of the injection molding method according to the present invention, the mold is vibrated for a predetermined time after the mold is opened.

  With such a feature, it is possible to avoid the fixed mold from adhering to the solidified molded product and perform continuous molding.

  The molten resin used in the injection molding method according to the present invention is characterized by containing 10% to 50% inorganic filler.

  With such a feature, vibration can be efficiently applied and a highly accurate injection molded product can be obtained.

  According to the injection molding nozzle according to the present invention, the molten resin is vibrated by the opening / closing pin 4 that is disposed in the flow path inside the injection nozzle and vibrates by the vibrator 2, so that the molten resin can be efficiently vibrated.

1 is a schematic block diagram of an injection molding machine according to the present invention. It is a fragmentary sectional view which shows roughly the injection molding machine which concerns on this invention with a part of metal mold | die. It is a fragmentary sectional view which shows roughly what used the vibration-proof board for the injection molding machine which concerns on this invention with a part of metal mold | die. It is a fragmentary sectional view showing roughly what installed the vibrator of the injection molding machine concerning the present invention in the outside of a resin channel with a part of metallic mold. It is a fragmentary sectional view which shows schematically the injection molding machine which concerns on a prior art with a part of metal mold | die.

Hereinafter, a first embodiment of an injection molding nozzle according to the present invention will be described with reference to FIGS. 1 and 2.
(First embodiment)
FIG. 1 is a schematic block diagram of an injection molding machine according to the present invention. FIG. 2 is a partial sectional view schematically showing an injection molding machine according to the present invention together with a part of a mold. FIG. 2A shows a state where the gate is opened by the open / close pin, and FIG. 2B shows a state where the gate is closed by the open / close pin.

  As shown in FIG. 1, the injection molding machine according to the present invention includes a molding machine main body 101, an injection nozzle constituting part 102, and a mold part 103.

  The molding machine main body 101 includes a control unit 111. The control unit 111 controls the flow state and pressure state of the flow path inside the injection nozzle 2. Although not shown, the control unit 111 also performs adjustment of the vibration frequency of the vibrator 115, its power ON / OFF, and advance / retreat of the drive actuator 116.

  The injection nozzle constituting unit 102 includes a resin injection port 112, an intra-nozzle path 113, an opening / closing pin 114, a vibrator 115, and a drive actuator 116. The resin injection port 112 is for injecting a shaping resin into the injection nozzle and communicates with the in-nozzle flow path 113. The in-nozzle flow path 113 is inside the injection nozzle 1 and allows the molten resin 7 to flow into the cavity 8 through the injection port 15. The open / close pin 114 propagates the opening / closing of the injection port 16 and the vibration from the vibrator to the molten resin 7. The vibrator 115 generates ultrasonic waves. The vibrator 115 is fixed to the opening / closing pin 114 and causes the opening / closing pin 114 to vibrate ultrasonically. The opening / closing pin drive actuator 116 is fixed to the injection nozzle 1. The open / close pin drive actuator 12 is fixed to the vibrator 115 or the open / close pin 114 via the shaft 10 and moves the open / close pin 114 in the axial direction.

  The mold part 103 includes a fixed mold 5 and a movable mold 6, and is provided with a gate 117 and a cavity 118. The gate 117 is an entrance that receives the molten resin 7 injected from the injection component 102 into the mold part 103. The cavity 118 is a recess provided in the mold, and is where the molten resin 7 from the injection component 102 accumulates.

  As shown in FIG. 2, the injection molding machine of the present invention comprises an injection nozzle 1, an opening / closing pin drive actuator 12, a nozzle fixing plate 3, a fixed mold 5 and a movable mold 6. The resin injection port 11 is for injecting resin from a molding machine main body (not shown), and is disposed on the side surface of the injection nozzle 1. The injection nozzle 1 is for injecting the resin injected from the resin injection port 11 into the mold part, and has a flow path through which the molten resin 7 flows, an open / close pin 4, a vibrator 2, and a shaft 10. The injection nozzle 1 is fixed by a nozzle fixing plate 3 so as not to move in the front-rear direction with respect to the mold during the injection molding process. Further, the injection nozzle 1 is always in close contact with the fixed mold 5 via the nozzle fixing plate 3.

  The open / close pin 4 has a rod shape and is connected to the open / close pin drive actuator 12 via the vibrator 2 and the shaft 10. When the drive actuator 2 drives the shaft 10, the open / close pin 4 also advances and retracts in the axial direction, and the tip of the open / close pin opens and closes the injection port 16. Thereby, injection of the molten resin 7 from the injection port 16 can be controlled.

  In FIG. 2A, the opening / closing pin 4 is retracted and the injection port 16 is open. In this state, the molten resin 7 can be injected from the injection port 16.

  The vibrator 2 is fixed to an end of the opening / closing pin opposite to the injection port 16 and connected to the control box 13 (not shown). When the vibrator 2 generates ultrasonic waves, the open / close pin 4 vibrates in the same manner due to the vibration of the vibrator 2. Here, the ultrasonic wave is a sound wave having a frequency exceeding the audible range, and generally means 20 kHz or more.

  The opening / closing pin drive actuator 12 is fixed to the end surface of the injection nozzle 1 opposite to the injection port 16 and is connected to the control box 13. The opening / closing pin drive actuator 12 moves the vibrator 2 and the opening / closing pin 4 forward and backward in the axial direction of the opening / closing pin 4 via the rod-shaped shaft 10. The opening / closing pin drive actuator 12 may be electromagnetic or mechanical.

  The control box 13 controls the operation of the opening / closing pin drive actuator 12 and the vibrator 2. For example, the movement of the shaft of the open / close pin drive actuator 12 is advanced, the frequency of the vibrator 2, and the start and stop of ultrasonic oscillation.

  The nozzle fixing plate 3 fixes the injection nozzle 1 to the fixed mold 5. The fixed mold 5 stably connects the nozzle tip 15 and the movable mold 6. The movable mold 6 is provided with a cavity 8 as a recess, and has a structure in which the molten resin 7 injected from the injection port 16 is accumulated. When the opening / closing pin 4 closes the injection port 16, the front end surface of the opening / closing pin 16 also serves as a lid for the cavity 8.

  FIG. 2B shows a state in which each component is the same as (A), and the open / close pin 4 is advanced by the open / close pin drive actuator 12 to close the injection port 16 and is closed.

  Next, a method for injection molding using the present invention will be described. The molten resin 7 is injected into a resin injection port from a molding machine main body 101 (not shown) and reaches a flow path inside the injection nozzle. Here, the control box 13 generates ultrasonic waves in the vibrator 2 and vibrates the open / close pin 4. Since the molten resin 7 filled in the flow path inside the injection nozzle 1 is in contact with the opening / closing pin 4, the molten resin 7 also vibrates due to the vibration of the opening / closing pin 4.

  In a state where the molten resin 7 is sufficiently vibrated, the control box 13 controls the open / close pin drive actuator 12 to retract the open / close pin 4 through the shaft 10 and open the injection port 16. As a result, the molten resin 7 is injected from the injection port 16, reaches the cavity 8 through the gate 9, and the cavity 8 is filled with the molten resin 7.

  After a predetermined amount required for injection molding is injected, the control box 13 controls the open / close pin drive actuator 12 to advance the open / close pin 4 and close the injection port 16. The control box 13 continues to control the vibrator 2 so that ultrasonic waves oscillate even after the injection port 16 is closed. The control box 13 performs control so that the vibrator 2 transmits ultrasonic waves after a predetermined time has elapsed or until the movable cavity is opened and the molded product is taken out.

  Here, when the next molded product is continuously produced, if the molten resin 7 is filled in the flow path in the injection nozzle, the molten resin 7 is also ultrasonically vibrated by the open / close pin 4 that continues the ultrasonic vibration. It becomes a state. After a predetermined time has elapsed, the movable mold 6 is opened and the molded product is taken out. After the movable mold 6 is closed, the control box 13 controls the open / close pin drive actuator 12 to retract the open / close pin 4. Then, the next molten resin 7 is injected into the cavity 8. Thereby, the molten resin 7 which is ultrasonically vibrated again is injected into the cavity 8.

  As described above, the following effects can be obtained by the embodiment described above.

  First, since the molten resin 7 is vibrated via the opening / closing pin 4 inside the injection nozzle 1, the molten resin 7 can be vibrated efficiently. In particular, since the open / close pin 4 has a smaller mass than the injection nozzle 4, the vibrator 2 can be made small. Further, since the vibrator 2 can be disposed inside the injection nozzle 1, the entire injection molding machine can be reduced in size.

  Secondly, according to the present invention, since ultrasonic waves can be efficiently applied to the resin, the resin fluidity is improved. For this reason, when there is no restriction | limiting especially by a product shape, the diameter of the gate 9 and the front-end | tip diameter of the opening-and-closing pin 4 can be enlarged to (phi) 2.0 mm or more. This eliminates the need to pour the molten resin 7 at a high pressure into the narrow gate when the present invention is not used. That is, the molten resin 7 can be poured into the cavity 8 without generating shear heat at a high pressure. Therefore, since molding conditions such as temperature and pressure can be relaxed, it is possible to avoid mold wear and detailed shape damage due to thermal load and injection pressure, and extend the life of the mold.

  Thirdly, according to the present invention, ultrasonic waves can be continuously applied to the resin even after the molten resin 7 has been filled into the cavity 8, so that a highly accurate molded product can be obtained.

  Fourth, since the front end surface of the open / close pin 4 of the present invention device is directly part of the cavity 8, it is possible to avoid complication of the mold structure. For this reason, it is possible to shorten the time until the applied ultrasonic vibration is stabilized and the operation time such as mold opening and closing, the injection molding cycle time is shortened, and the injection molding can be speeded up.

  Fifth, since the present invention can be used even if the mold structure is made into a hot runner, the molten resin 7 in the vicinity of the cavity 8 remains in a molten state and does not create a runner. For this reason, a runner cutting and discharging mechanism is not required, and it is possible to avoid a complicated mold structure. In addition, since the mold size can be reduced, the mold manufacturing cost can be reduced.

Sixth, in the present invention, since the fluidity is enhanced by imparting vibration to the molten resin 7, the temperature and pressure of the injection nozzle 1, the fixed mold 5 and the movable mold 6 are set to be higher than those of the prior art. It can be kept low. Thereby, the adjustment range of molding conditions is widened, and mold shape transferability and shape dimensional accuracy can be improved. Furthermore, workability is improved by lowering the mold temperature.
(Second Embodiment)
FIG. 3 shows a configuration in which a vibration isolating plate 17 is disposed between the nozzle fixing plate 3 and the fixed mold 5. The vibration isolator 17 has a function of not transmitting ultrasonic vibration to the opposite surface of the plate. The vibration isolator 17 can prevent inadvertent resonance without transmitting vibrations to each other even when the stationary mold 5 and the nozzle fixing plate 5 vibrate.
(Third embodiment)
FIG. 4 shows the vibrator 2 installed outside the resin flow path. By setting the vibrator installation location outside the flow path, vibration can be applied to the open / close pin 4 more stably than when operating inside the resin melted at high temperature, and high-precision molding can be performed.

DESCRIPTION OF SYMBOLS 1 Injection nozzle 2 Vibrator 3 Nozzle fixed plate 4 Opening / closing pin 5 Fixed side metal mold 6 Movable side metal mold 7 Molten resin 8 Cavity 9 Gate 10 Shaft 11 Resin injection port 12 Opening / closing pin drive actuator 13 Control box 14 Screw 15 Nozzle tip 16 Injection port 17 Antivibration plate 101 Molding machine main body unit 102 Injection nozzle component 103 Mold unit 111 Control unit 112 Resin injection port 113 Nozzle flow path 114 Opening / closing pin 115 Vibrator 116 Drive actuator 117 Gate 118 Cavity

Claims (13)

A flow path through which the molten resin injected from the resin injection port flows;
An injection port for injecting the molten resin into a mold;
An open / close pin that opens and closes the injection port by moving back and forth in the axial direction;
A vibrator that is fixed to the open / close pin and oscillates an ultrasonic wave;
An open / close pin drive actuator for moving the open / close pin forward and backward,
An injection molding nozzle, wherein an ultrasonic wave oscillated from the vibrator vibrates the molten resin through the opening / closing pin. The injection molding nozzle according to claim 1, wherein the vibrator is fixed to an end of the opening / closing pin facing the injection port. The injection molding nozzle according to claim 2, wherein the opening / closing pin penetrates to the outside of the flow path. The injection molding nozzle according to any one of claims 1 to 3, wherein the open / close pin drive actuator is disposed on an end surface of the injection nozzle facing the injection port.   5. The injection according to claim 1, wherein a frequency of an ultrasonic wave oscillated by the vibrator is the same as a position of a cavity of the mold at a resonance node. Molding nozzle.   The injection molding nozzle according to any one of claims 1 to 5, further comprising a nozzle fixing plate that fixes a side surface of the injection nozzle and the mold.   An injection molding machine comprising the injection molding nozzle according to any one of claims 1 to 6.   The injection molding machine having an injection molding nozzle according to claim 6, further comprising a vibration isolating plate between the nozzle fixing plate and the mold.   An injection molded product produced by the injection molding machine according to claim 7 or 8. Injecting molten resin from a resin injection port provided in the injection nozzle;
A step of vibrating the molten resin through an open / close pin that opens and closes an injection port by an ultrasonic wave oscillated by a vibrator;
And an injection step of injecting the molten resin from an injection port. After the injection step, closing the injection port with the opening and closing pin;
The injection molding method according to claim 10, further comprising a post-injection vibration step of vibrating the open / close pin by a vibrator even after the injection port is closed.   12. The injection molding method according to claim 11, wherein in the post-injection vibration step, the open / close pin is vibrated even after the mold is opened.   The injection molding method according to claim 11 or 12, wherein the molten resin contains 10% to 50% of an inorganic filler.

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