CN111452314A

CN111452314A - Injection molding machine

Info

Publication number: CN111452314A
Application number: CN202010053660.1A
Authority: CN
Inventors: 樽家宏治; 中田匡英; 水岛启人
Original assignee: Toyo Machinery and Metal Co Ltd
Current assignee: Toyo Machinery and Metal Co Ltd
Priority date: 2019-01-18
Filing date: 2020-01-17
Publication date: 2020-07-28
Also published as: JP2020116747A; JP7190916B2

Abstract

The invention provides an injection molding machine which reduces the operation burden of an operator in the cleaning operation. An injection molding machine having a mold clamping unit for opening and closing a mold and clamping the mold, and an injection unit for injecting a plasticized resin, wherein a heating cylinder of the injection unit moves between an injection position and a standby position, a nozzle for injecting the plasticized resin is formed at a tip of the heating cylinder, the injection position is a position where the heating cylinder communicates with a cavity of the mold clamped by the mold, and the standby position is a position where the heating cylinder is separated from the mold, the injection molding machine having a conveyor disposed on a discharge path for discharging the plasticized resin from the heating cylinder at the standby position, and conveying the plasticized resin discharged from the nozzle to the outside of the injection molding machine.

Description

Injection molding machine

Technical Field

The present invention relates to an injection molding machine that injects a plasticized resin into a mold to produce an injection-molded product.

Background

Patent document 1 discloses a vertical injection molding machine having a heating cylinder that moves up and down between a contact position where the heating cylinder contacts a resin injection hole of a mold and a retreat limit position above the contact position. Further, patent document 1 describes that a purging operation for discharging the plasticized resin in the heating cylinder is performed.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2012-153110

Disclosure of Invention

Problems to be solved by the invention

In the injection molding machine described in patent document 1, the operator needs to place the receiving tray for receiving the plasticized resin directly below the heating cylinder before performing the cleaning operation and remove the receiving tray from the positioning portion before performing the injection molding. In addition, when the amount of the plasticized resin discharged by the purge operation is large, the operator needs to remove the plasticized resin in the receiving tray in the middle of the purge operation.

Therefore, the injection molding machine having the above-described configuration has a problem in that the operation load of the operator is large when the machine cleaning operation is performed. This problem occurs not only in a vertical injection molding machine but also in a horizontal injection molding machine in which a heating cylinder moves in the horizontal direction.

The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide an injection molding machine that reduces the operation load on the operator during the machine cleaning operation.

Means for solving the problems

In order to solve the above problems, the present invention provides an injection molding machine including a mold clamping unit that opens and closes a mold, and an injection unit that injects a plasticized resin, wherein a heating cylinder of the injection unit moves between an injection position that communicates with a cavity of the mold that has been clamped and a standby position that is separated from the mold, a nozzle that injects the plasticized resin is formed at a tip of the heating cylinder, the injection molding machine includes a conveyor that is disposed on a discharge path that discharges the plasticized resin from the heating cylinder in the standby position, and conveys the plasticized resin discharged from the nozzle to the outside of the injection molding machine.

According to the above configuration, the plasticized resin discharged from the heating cylinder when the injection unit is located at the standby position is automatically conveyed to the outside of the injection molding machine by the conveyor. As a result, when the machine cleaning operation is performed, the operation burden of the operator who attaches and detaches the tray and the like can be reduced.

In the injection molding machine according to the present invention, the conveyor may switch the conveying speed in conjunction with a discharge speed of the plasticized resin from the nozzle.

If the conveying speed of the conveyor is too slow compared to the discharge speed of the plasticized resin, the plasticized resin is formed into a dough state on the conveying surface of the conveyor. On the other hand, if the conveying speed of the conveyor is too high compared with the discharge speed of the plasticized resin, excessive electric power may be consumed or the motor driving the conveyor may be in an overheated state. Therefore, as in the above-described configuration, it is desirable to switch the conveying speed of the conveyor in conjunction with the discharge speed of the plasticized resin.

For example, the injection molding machine of the present invention may be characterized in that the injection unit has a screw that is rotatable, movable forward, and movable backward in the heating cylinder, and the conveyor conveys the plasticized resin at a first speed when the screw moves and at a second speed slower than the first speed when the screw stops in a state where the injection unit is located at the standby position. By this, the resin dropping from the nozzle hole while the screw is stopped can be removed.

For example, in the injection molding machine according to the present invention, the conveyor may convey the plasticized resin at the first speed in a purge operation of advancing the screw to discharge the plasticized resin in the heating cylinder, and the conveyor may convey the plasticized resin at a third speed slower than the first speed in a metering operation of rotating and retracting the screw to store the plasticized resin in the heating cylinder.

In the injection molding machine according to the present invention, the injection molding machine may include a cap that moves between a blocking position at which a nozzle hole at a tip end of the nozzle is blocked and an open position at which the nozzle hole is opened, the cap being disposed at the blocking position, the injection unit may perform the metering operation, the cap being disposed at the open position, and the injection unit may perform the purge operation.

According to the above configuration, the plasticized resin can be prevented from leaking from the heating cylinder when the injection unit is located at the standby position. Further, by performing the metering operation with the lid disposed at the closed position, the back pressure in the heating cylinder increases, and the efficiency of the metering operation improves.

In the injection molding machine according to the present invention, the injection molding machine may include a cooling device that cools the plasticized resin conveyed by the conveyor.

The plasticized resin in a molten state sticks to the surface of the conveyor and becomes difficult to peel. Therefore, according to the above configuration, the effect of promoting the solidification of the plasticized resin and facilitating the separation from the surface of the conveyor can be expected.

As an example, the injection molding machine of the present invention may be a vertical type in which the standby position is located vertically above the injection position, wherein the conveyor is moved to an advanced position directly below the heating cylinder after the injection unit is moved to the standby position, and the conveyor is moved to a retracted position away from a movement path of the heating cylinder before the injection unit is moved to the injection position.

In the injection molding machine according to the present invention, the conveyor may advance and retreat along a conveying direction of the plasticized resin between the advance position and the retreat position.

According to the above configuration, the space required for moving the conveyor can be reduced.

In another example, the injection molding machine of the present invention may be of a horizontal type in which the injection position and the standby position are separated in a horizontal direction, and the conveyor may be fixed directly below the nozzle of the heating cylinder in the standby position.

In the injection molding machine according to the present invention, the injection molding machine may include a guide plate that moves between a guide position on a movement path of the heating cylinder and a retracted position away from the movement path of the heating cylinder, the conveyor may be fixed directly below the guide plate at the guide position, the guide plate may move to the guide position after the injection unit moves to the standby position, and the guide plate may move to the retracted position before the injection unit moves to the injection position.

According to the above configuration, the plasticized resin discharged in large quantities from the heating cylinder by the purge operation is guided to the conveyor by being abutted against the guide plate at the guide position. As a result, in the horizontal injection molding machine, the plasticized resin discharged by the purge operation can be reliably and efficiently discharged to the outside of the injection molding machine by the conveyor.

Effects of the invention

According to the present invention, the plasticized resin discharged from the heating cylinder when the injection unit is located at the standby position is automatically conveyed to the outside of the injection molding machine by the conveyor. As a result, when the machine cleaning operation is performed, the operation burden of the operator who attaches and detaches the tray and the like can be reduced.

Drawings

Fig. 1 is a front view of a vertical injection molding machine of a first embodiment.

Fig. 2A-2D are schematic enlarged views of the injection unit.

Fig. 3 is a hardware block diagram of an injection molding machine.

Fig. 4 is a flowchart of the resin discharge process.

Fig. 5 is a flowchart of the purge control process.

Fig. 6 is a side view of the horizontal injection molding machine of the second embodiment.

Fig. 7A and 7B are front views of the heating cylinder as viewed from the front end side.

Description of the reference numerals

10. 10a … injection molding machine, 20 … mold closing unit, 21 … mold, 22 … fixed mold, 23 … fixed mold plate, 24 … movable mold, 25 … movable mold plate, 26 … pull rod, 30 … injection unit, 31 … heating cylinder, 32 … screw, 33 … conveyor, 34 … fan (cooling device), 35 … cover, 36 … nozzle, 36a … nozzle hole, 37 … box, 37a, 37b, 37c … slit, 38 … guide plate, 40 … operation panel, 50 … controller, 51 … CPU, 52 … ROM, 53 … RAM, 61 … mold opening and closing motor, 62 … nozzle contact motor, 63 … metering motor, 64 … injection motor, 65 … conveyor advancing and retreating motor, 66 … conveyor driving motor, 67 cap advancing and retreating motor 67 …

Detailed Description

The injection molding machine 10 of the present invention is explained below based on the drawings. The embodiments of the present invention described below are merely examples of embodying the present invention, and the scope of the present invention is not limited to the described scope of the embodiments. Therefore, the present invention can be implemented with various modifications to the embodiments.

(first embodiment)

Fig. 1 is a front view of an injection molding machine 10 of a first embodiment. Fig. 2A-2D are schematic enlarged views of the injection unit 30. Fig. 3 is a hardware block diagram of the injection molding machine 10. The injection molding machine 10 is a device for producing an injection molded product by injecting a plasticized resin into a mold. The injection molding machine 10 of the first embodiment is a so-called "vertical type". As shown in fig. 1 to 3, the injection molding machine 10 mainly includes a mold clamping unit 20, an injection unit 30, an operation panel 40, and a controller 50.

The mold clamping unit 20 opens and closes and clamps the mold 21. Specifically, the mold clamping unit 20 mainly includes a fixed platen 23 that supports the fixed mold 22, a movable platen 25 that supports the movable mold 24 directly above the fixed mold 22, and a mold opening/closing motor 61 that moves the movable platen 25 in the vertical direction along the tie bars 26.

The mold opening and closing motor 61 is a servomotor that moves the movable platen 25 in the vertical direction. The driving force of the mold opening and closing motor 61 is transmitted to the movable platen 25 by, for example, a toggle mechanism (not shown). As shown in fig. 1, when the movable platen 25 is raised, the fixed mold 22 is separated from the movable mold 24. On the other hand, when the movable platen 25 is lowered, the fixed mold 22 abuts against the movable mold 24, and a cavity (internal space) is formed inside the mold 21. When a downward pressure is further applied to the movable platen 25, the fixed mold 22 and the movable mold 24 are clamped.

The injection unit 30 plasticizes, meters, and injects the resin supplied from a hopper (not shown). The injection unit 30 of the first embodiment is disposed above the mold clamping unit 20. The injection unit 30 mainly has a heating cylinder 31, a screw 32, a conveyor 33, a fan 34, a cap 35, a nozzle contact motor 62, a metering motor 63, an injection motor 64, a conveyor advancing and retreating motor 65, a conveyor drive motor 66, and a cap advancing and retreating motor 67.

The heating cylinder 31 is a cylindrical member extending in the vertical direction. A nozzle hole 36a of a nozzle 36 for injecting plasticized resin is formed at the tip (lower end) of the heating cylinder 31, and a supply port (not shown) for receiving supply of resin from a hopper is formed at the base end (upper end) side. Further, a linear inner space from the supply port to the nozzle 36 is formed inside the heating cylinder 31. A belt heater (not shown) for heating the heating cylinder 31 may be attached to the outer peripheral surface of the heating cylinder 31.

The nozzle contact motor 62 is a servo motor that moves the injection unit 30 in the vertical direction. The driving force of the nozzle contact motor 62 is transmitted to the injection unit 30, and the injection unit 30 is moved in the vertical direction between the injection position (fig. 2A) and the standby position (fig. 2B to 2D). The injection position is a position where the nozzle 36 at the tip of the heating cylinder 31 enters an opening (not shown) provided in the movable die plate 25, and the internal space of the heating cylinder 31 communicates with the cavity of the mold 21. The standby position is a position where the nozzle 36 at the tip of the heating cylinder 31 is retracted from the opening of the movable die plate 25, and the heating cylinder 31 is separated from the mold 21. The standby position in the first embodiment is a position vertically above the injection position.

The screw 32 is a long rod-shaped member having a spiral groove formed on an outer peripheral surface thereof. The screw 32 is housed in an internal space of the heating cylinder 31 in a rotatable, forward-moving and backward-moving state. The metering motor 63 is a servomotor that rotates the screw 32 in the heating cylinder 31. The injection motor 64 is a servo motor that advances and retreats the screw 32 in the heating cylinder 31. The injection unit 30 performs a metering operation, an injection operation, and a purge operation by rotating or advancing and retreating the screw 32 in the heating cylinder 31.

The metering operation is an operation of storing a predetermined amount of the plasticized resin on the tip side (nozzle 36 side) of the heating cylinder 31 by rotating the screw 32. At this time, the resin supplied to the heating cylinder 31 is plasticized by frictional heat, shear heat, and heat generated by the belt heater generated between the heating cylinder 31 and the screw 32. The plasticized resin moves to the distal end side of the heating cylinder 31 along the spiral groove of the screw 32 and accumulates on the distal end side of the heating cylinder 31. As a result, the screw 32 moves backward while rotating in the heating cylinder 31.

The injection operation and the purge operation are operations for causing the plasticized resin accumulated on the tip side of the heating cylinder 31 to be injected (discharged) from the heating cylinder 31 through the nozzle 36 by advancing the screw 32. In the present specification, the operation of injecting the plasticized resin from the heating cylinder 31 when the injection unit 30 is located at the injection position is referred to as "injection operation", and the operation of discharging the plasticized resin from the heating cylinder 31 when the injection unit 30 is located at the standby position is referred to as "purge operation".

The conveyor 33 functions to convey the plasticized resin discharged from the heating cylinder 31 to the outside of the injection molding machine 10 when the injection unit 30 is located at the standby position. That is, the conveyor 33 is disposed on a discharge path (directly below the nozzle hole 36a) through which the plasticized resin is discharged from the heating cylinder 31 at the standby position. The conveyor advancing and retreating motor 65 is a servo motor that advances and retreats the conveyor 33. The conveyor drive motor 66 is a servo motor that drives the conveyor 33 to rotate.

The driving force of the conveyor advancing-retreating motor 65 is transmitted to the conveyor 33, and the conveyor 33 is advanced and retreated between the advanced position (fig. 2C, 2D) and the retreat position (fig. 2A, 2B)). The forward position is a position where the conveyance surface (upper surface) of the conveyor 33 is disposed directly below the nozzle 36 (nozzle hole 36a) at the front end of the heating cylinder 31 in the standby position. The retreat position is a position where the conveyor 33 is separated from the moving path of the heating cylinder 31. The forward position and the retreat position are positions separated in the conveying direction (i.e., the left-right direction in fig. 2A to 2D) in which the conveyor 33 conveys the plasticized resin. That is, the conveyor 33 advances and retreats in the conveying direction of the plasticized resin.

When the conveyor 33 is located at the forward position, the plasticized resin discharged from the nozzle 36 (nozzle hole 36a) at the tip of the heating cylinder 31 at the standby position falls on the conveyance surface of the conveyor 33, and the injection unit 30 (heating cylinder 31) cannot move from the standby position to the injection position. On the other hand, when the conveyor 33 is located at the retreat position, the plasticized resin discharged from the nozzle 36 (nozzle hole 36a) at the tip of the heating cylinder 31 at the standby position does not fall on the conveyance surface of the conveyor 33, and the injection unit 30 (heating cylinder 31) can move between the injection position and the standby position.

Further, the driving force of the conveyor driving motor 66 is transmitted to the conveyor 33, and the conveyor 33 rotates in a direction (counterclockwise direction in fig. 2A to 2D) in which the plasticized resin dropped on the conveying surface is discharged to the outside of the injection molding machine 10. The conveyor 33 may be configured to be capable of switching the conveyance speed. The conveyor 33 according to the first embodiment can be switched at least between a high speed (first speed) and a low speed (second speed). The first speed is set based on, for example, the discharge speed of the plasticized resin during the purge operation. The second speed is a speed slower than the first speed.

The fan 34 is a cooling device that functions to cool the plasticized resin conveyed on the conveyor 33. Specifically, the fan 34 blows air toward the conveying surface of the conveyor 33. The fan 34 is fixed to a predetermined position of the conveyor 33. That is, the fan 34 moves forward and backward integrally with the conveyor 33 that moves between the forward position and the retracted position. The blowing speed of the fan 34 (blowing amount per unit time) can be switched in conjunction with the conveying speed of the conveyor 33.

The cap 35 abuts on the front end of the heating cylinder 31 and serves to close the nozzle 36. The lid advancing and retracting motor 67 is a servo motor that advances and retracts the lid 35. The driving force of the cap advancing-retracting motor 67 is transmitted to the cap 35, and the cap 35 is advanced and retreated between a blocking position (fig. 2D) at which the nozzle 36 is blocked and an opening position (fig. 2A to 2C) at which the nozzle 36 is opened.

As shown in fig. 2A to 2D, the injection unit 30 has a heating cylinder 31, a conveyor 33, and a case 37 that houses a cover 35. The box 37 has

slits

37a, 37b, and 37c through which the heating cylinder 31, the conveyor 33, and the cover 35 are inserted. That is, the heating cylinder 31, the conveyor 33, and the cover 35 pass through the

slits

37a, 37b, and 37c and advance and retreat with respect to the internal space of the case 37.

The nozzle 36 at the front end of the heating cylinder 31 is always located in the internal space of the case 37. Thereby, the operator can be prevented from hitting the plasticized resin injected from the nozzle 36. However, the case 37 may have a door (not shown) or the like that exposes the internal space for maintenance.

The operation panel 40 is a user interface having a display screen for displaying various information to be notified to the operator, and buttons, switches, a numeric keypad, and the like for receiving an operation by the operator. In addition, the operation panel 40 may have a touch panel overlapping with the display screen. The operation panel 40 receives, for example, an operation of the operator to start the injection operation and an operation of the operator to start the purge operation, and outputs an operation signal corresponding to the received operation to the controller 50.

The controller 50 controls the overall operation of the injection molding machine 10. The controller 50 acquires an operation signal output from the operation panel 40 and an encoding signal output from an encoder (not shown) of each of the motors 61 to 67. The controller 50 drives the motors 61 to 67 and the fan 34 based on the acquired various signals.

The controller 50 includes, for example, a CPU (Central Processing Unit) 51 as an arithmetic Unit, a ROM (Read-Only Memory) 52 in which various programs are stored, and a RAM (Random Access Memory) 53 as a work area of the arithmetic Unit. Further, each process described later can be realized by the CPU51 reading and executing a program stored in the ROM 52.

However, the specific configuration of the controller 50 is not limited to this, and may be realized by hardware such as an ASIC (application specific integrated Circuit) or an FPGA (Field-Programmable Gate Array).

Next, the operation of the injection molding machine 10 according to the first embodiment will be described with reference to fig. 4 and 5. Fig. 4 is a flowchart of the resin discharge process. Fig. 5 is a flowchart of the purge control process. The resin discharge process is started at a timing when the injection molding is ended, for example. As shown in fig. 2A, at the start of the resin discharge process, the injection unit 30 (heating cylinder 31) is disposed at the injection position, the conveyor 33 is disposed at the retreat position, and the cover 35 is disposed at the open position.

First, the controller 50 drives the nozzle contact motor 62 to raise the injection unit 30 (heating cylinder 31) from the injection position to the standby position (S11). As a result, as shown in fig. 2B, the heating cylinder 31 is lifted and separated from the mold 21, and the nozzle hole 36a of the nozzle 36 is exposed.

Next, the controller 50 drives the conveyor advancing-retreating motor 65 and the conveyor driving motor 66 to advance the conveyor 33 from the retracted position to the advanced position, and rotates the conveyor 33 at a low speed (S12). Thus, as shown in fig. 2C, the conveyor 33 is disposed directly below the heating cylinder 31 in the standby position. That is, the controller 50 moves the conveyor 33 to the forward position after moving the injection unit 30 (heating cylinder 31) to the standby position. In addition, the controller 50 rotates the fan 34.

Next, the controller 50 waits for the execution of the subsequent processing until an instruction is input by the operator through the operation panel 40 (S13). When the operation of the operator for instructing the execution of the purge operation is received through the operation panel 40 (S13: purge), the controller 50 executes the purge control process (S14).

As shown in fig. 5, the controller 50 drives the lid advancing-retracting motor 67 to advance the lid 35 from the open position to the closed position (S21). As a result, as shown in fig. 2D, the cap 35 abuts on the distal end of the heating cylinder 31, and the nozzle 36 is closed. As a result, the plasticized resin in the heating cylinder 31 can be prevented from leaking little by little from the nozzle 36 (nozzle hole 36a) by gravity.

Subsequently, the controller 50 rotates the metering motor 63 to rotate the screw 32 to retract (S22). Thereby, the plasticized resin is stored at the distal end side of the heating cylinder 31 (metering operation). Then, the controller 50 waits for the subsequent processing to be executed (no in S23) until the screw 32 reaches a predetermined position (stores a predetermined amount of plasticized resin) based on the encoder value output from the encoder of the metering motor 63.

When the controller 50 determines that the screw 32 has moved backward to the predetermined position (yes in S23), the drive current supplied to the conveyor drive motor 66 is increased to switch the conveyor 33 to high-speed rotation (S24). Further, the controller 50 drives the lid advancing-retreating motor 67 to retreat the lid 35 from the closing position to the opening position (S25). Thereby, the state of fig. 2D returns to the state of fig. 2C. Further, the processing in steps S24 and S25 may be performed in parallel or in reverse order.

Next, the controller 50 drives the injection motor 64 to advance the screw 32 (S26). Thereby, the plasticized resin accumulated on the distal end side of the heating cylinder 31 is discharged through the nozzle 36 (purge operation). The plasticized resin discharged from the nozzle 36 is dropped onto the conveying surface of the conveyor 33, and is conveyed to the outside of the injection molding machine 10 by the conveyor 33 rotating at a high speed. The plasticized resin is cooled by the air supplied from the fan 34 while being conveyed on the conveyor 33.

Next, the controller 50 determines whether the number of times of execution of the purge operation (i.e., the number of times of repetition of steps S21 to S26) reaches a predetermined number of times (S27). A predetermined default value for the number of times the purge action is performed may be stored in the RAM53, or the number of times the purge action is performed may be specified by the operator via the operation panel 40.

When the controller 50 determines that the number of times of execution of the cleaning operation has not reached the predetermined number of times (no in S27), the drive current supplied to the conveyor drive motor 66 is reduced, and the conveyor 33 is switched to the low-speed rotation (S28). Then, the controller 50 returns to step S21 to continue the processing.

On the other hand, when the controller 50 determines that the number of times of executing the cleaning operation has reached the predetermined number of times (yes in S27), the drive current supplied to the conveyor drive motor 66 is reduced, and the conveyor 33 is switched to the low-speed rotation (S29). Then, the controller 50 ends the purge control process. After the predetermined number of times of the cleaning operation is performed (S27: yes), the controller 50 may execute so-called "idle driving" in which the injection motor 64 is driven to advance and retract the screw 32 in the heating cylinder 31.

Subsequently, returning to fig. 4, the controller 50 executes the processing from step S13 again. When the operator has received an instruction to execute the injection operation via the operation panel 40 (S13: injection), the controller 50 stops the conveyor driving motor 66 and drives the conveyor advancing-retracting motor 65 to retract the conveyor 33 from the advanced position to the retracted position (S15). Also, the controller 50 stops the fan 34. Thereby, the state of fig. 2C returns to the state of fig. 2B.

Next, the controller 50 drives the nozzle contact motor 62 to lower the injection unit 30 (heating cylinder 31) from the standby position to the injection position (S16). Thereby, the state returns from fig. 2B to fig. 2A. That is, the controller 50 moves the conveyor 33 to the retreat position before moving the injection unit 30 (heating cylinder 31) to the injection position.

Then, the controller 50 performs injection molding (S17). Specifically, the controller 50 repeats a mold closing operation, a mold clamping operation, a metering operation, an injection operation, a mold opening operation, and a molded product discharge operation a predetermined number of times. Since the process of step S17 is already known, a detailed description is omitted. When the injection molding is performed a predetermined number of times, the controller 50 returns to step S11 again to continue the process.

According to the injection molding machine 10 of the first embodiment, for example, the following operational effects are achieved.

According to the first embodiment, the plasticized resin discharged from the heating cylinder 31 at the standby position by the purge operation is automatically conveyed to the outside of the injection molding machine 10 by the conveyor 33. As a result, when the machine cleaning operation is performed, the operation burden of the operator who attaches and detaches the tray and the like can be reduced.

When the conveying speed of the conveyor 33 is too slow compared to the discharge speed of the plasticized resin, the plasticized resin is in a state of a dough on the conveying surface of the conveyor 33. On the other hand, if the conveying speed of the conveyor 33 is too high compared to the discharge speed of the plasticized resin, excessive power may be consumed or the conveyor drive motor 66 may be in an overheated state. Therefore, as in the first embodiment, it is desirable to switch the conveying speed of the conveyor 33 in conjunction with the discharge speed of the plasticized resin.

Thereby, the plasticized resin discharged in step S26 is conveyed in a band shape on the conveying surface of the conveyor 33. As a result, the slit 37b can be formed to the minimum height at which the conveyor 33 can pass, and therefore, the operator can be prevented from mistakenly inserting his hand into the case 37 through the slit 37 b.

Further, as in the first embodiment, by closing the nozzle 36 (nozzle hole 36a) with the cap 35, the plasticized resin can be prevented from leaking from the heating cylinder 31 when the injection unit 30 is located at the standby position. Further, by performing the metering operation with the lid 35 disposed at the closed position, the back pressure in the heating cylinder 31 becomes high, and the efficiency of the metering operation improves. Further, while the lid 35 is in the blocking position (S21 to S25), the conveyor driving motor 66 may be stopped.

Alternatively, the cover 35 may be omitted. In this case, the conveying speed of the conveyor 33 during the metering operation (S22 to S23) may be set to a third speed (medium speed) which is slower than the first speed and faster than the second speed. This enables the conveying speed of the conveyor 33 to be more accurately linked to the conveying speed of the plasticized resin passing through the nozzle 36. However, the relationship between the second speed and the third speed is not limited to the above example, and the second speed > the third speed may be used, or the second speed may be equal to the third speed.

The conveying speed of the conveyor 33 during the metering operation (S22 to S23) may be the first speed. That is, the controller 50 may cause the conveyor 33 to convey the plasticized resin at the first speed when the screw 32 moves (rotates, advances, and retreats) (S22 to S26), and cause the conveyor 33 to convey the plasticized resin at the second speed when the screw 32 stops (S12 to S13).

In addition, the plasticized resin in a molten state sticks to the surface of the conveyor 33 and becomes difficult to peel. Then, as in the first embodiment, the plasticized resin on the conveyor 33 is cooled by the fan 34, whereby the effect of promoting solidification of the plasticized resin and facilitating separation from the surface of the conveyor 33 can be expected. A specific example of the cooling device is not limited to the fan 34, and may be a device that generates cool air using a refrigerant.

In the first embodiment, the example in which the conveyor 33 is moved forward and backward in the conveying direction of the plasticized resin is described. This reduces the space required for moving the conveyor 33, and therefore, the slit 37b can be reduced in size. However, the moving trajectory of the conveyor 33 is not limited to the above example, and may swing on a horizontal plane.

(second embodiment)

Next, an injection molding machine 10A according to a second embodiment will be described with reference to fig. 6 and fig. 7A and 7B. Fig. 6 is a side view showing a schematic structure of the injection molding machine 10A. Fig. 7A and 7B are front views of the heating cylinder 31 as viewed from the distal end side thereof. Note that the same reference numerals are given to components that perform the same functions as those of the first embodiment, and detailed descriptions thereof are omitted.

The injection molding machine 10A of the second embodiment is a so-called "horizontal type" in which the injection unit 30 (heating cylinder 31) is moved in the horizontal direction between an injection position and a standby position, which are separated in the horizontal direction. That is, the injection molding machine 10A of the second embodiment is different from the injection molding machine 10 of the first embodiment in that the positional relationship of the main constituent members 22 to 26, 31 to 32 is reversed by 90 °.

In addition, the injection molding machine 10A of the second embodiment has a guide plate 38 instead of the cover 35. However, the injection molding machine 10A may also have a cover 35. The guide plate 38 functions to guide the plasticized resin discharged from the heating cylinder 31 by the purging operation to the conveying surface of the conveyor 33. The driving force of the guide plate advancing and retreating motor (not shown) is transmitted to the guide plate 38, and the guide plate 38 is moved between the retreat position (fig. 7A) and the guide position (fig. 7B).

The retracted position is a position away from the moving path of the heating cylinder 31. The guide position is a position on the moving path of the heating cylinder 31. That is, when the guide plate 38 is located at the retreat position, the plasticized resin discharged from the heating cylinder 31 at the standby position does not fall on the guide plate 38, and the injection unit 30 (the heating cylinder 31) can move between the standby position and the injection position. On the other hand, when the guide plate 38 is located at the guide position, the plasticized resin discharged from the heating cylinder 31 at the standby position falls on the guide plate 38, and the injection unit 30 (heating cylinder 31) cannot move from the standby position to the injection position.

The conveyor 33 according to the second embodiment is fixed directly below the nozzle 36 at the tip of the heating cylinder 31 in the standby position and directly below the guide plate 38 in the guide position. That is, both the plasticized resin that leaks little by little from the heating cylinder 31 at the standby position and the plasticized resin that is discharged in large quantities from the heating cylinder 31 at the standby position and falls on the guide plate 38 fall on the conveying surface of the conveyor 33, and are conveyed to the outside of the injection molding machine 10A.

The injection molding machine 10A of the second embodiment executes the processing shown in fig. 4 and 5. However, in the second embodiment, the forward and backward movement of the conveyor in steps S12, S15 and the processing in steps S21, S25 are omitted. Further, the controller 50 of the second embodiment moves the guide plate 38 from the retracted position to the guide position after moving the injection unit 30 (heating cylinder 31) from the injection position to the standby position (i.e., immediately after performing step S11). The controller 50 of the second embodiment moves the guide plate 38 from the guide position to the retracted position before moving the injection unit 30 (heating cylinder 31) from the standby position to the injection position (i.e., immediately before performing step S16).

According to the second embodiment, the plasticized resin discharged in a large amount from the nozzle 36 at the tip of the heating cylinder 31 by the purging operation is guided to the conveying surface of the conveyor 33 while hitting the guide plate 38 at the guide position. As a result, in the horizontal injection molding machine 10A, the plasticized resin discharged by the purge operation can be reliably and efficiently discharged to the outside of the injection molding machine 10A by the conveyor 33.

Claims

1. An injection molding machine having a mold clamping unit for opening and closing a mold and clamping the mold, and an injection unit for injecting a plasticized resin,

a heating cylinder of the injection unit moves between an injection position where the heating cylinder communicates with a cavity of the mold to be clamped and a standby position where the heating cylinder is separated from the mold, a nozzle for injecting plasticized resin is formed at a tip of the heating cylinder,

the injection molding machine includes a conveyor disposed on a discharge path through which the plasticized resin is discharged from the heating cylinder at the standby position, and configured to convey the plasticized resin discharged from the nozzle to an outside of the injection molding machine.

2. The injection molding machine of claim 1,

the conveyor switches the conveying speed in conjunction with the discharge speed of the plasticized resin from the nozzle.

3. The injection molding machine of claim 2,

the injection unit has a screw capable of rotating, advancing and retreating within the heating cylinder,

in a state where the injection unit is located at the standby position,

the conveyor conveys plasticized resin at a first speed while the screw is moving,

the conveyor conveys plasticized resin at a second speed slower than the first speed while the screw is stopped.

4. The injection molding machine of claim 3,

the conveyor conveys the plasticized resin at the first speed in a purge operation of advancing the screw to discharge the plasticized resin in the heating cylinder,

the conveyor conveys the plasticized resin at a third speed slower than the first speed in a metering operation of rotating and retracting the screw to store the plasticized resin in the heating cylinder.

5. The injection molding machine of claim 4,

the injection molding machine has a cap that moves between a blocking position where a nozzle hole at a leading end of the nozzle is blocked and an open position where the nozzle hole is opened,

configuring the cap in the blocking position, the injection unit performing the metering action,

configuring the cap in the open position, the injection unit performing the purge action.

6. Injection molding machine according to one of claims 1 to 5,

the injection molding machine has a cooling device that cools the plasticized resin conveyed on the conveyor.

7. Injection molding machine according to one of claims 1 to 6,

the injection molding machine is of a vertical type in which the standby position is located vertically above the injection position,

after the injection unit is moved to the standby position, the conveyor is moved to an advanced position directly below the heating cylinder,

before the injection unit moves to the injection position, the conveyor moves to a retreat position that is separated from a movement path of the heating cylinder.

8. The injection molding machine of claim 7,

the conveyor advances and retreats in a conveying direction of the plasticized resin between the advance position and the retreat position.

9. Injection molding machine according to one of claims 1 to 6,

the injection molding machine is of a horizontal type in which the injection position and the standby position are separated in a horizontal direction,

the conveyor is fixed just below the nozzle of the heating cylinder in the standby position.

10. The injection molding machine of claim 9,

the injection molding machine has a guide plate that moves between a guide position on a movement path of the heating cylinder and a retracted position away from the movement path of the heating cylinder,

the conveyor is fixed directly below the guide plate in the guide position,

the guide plate moves to the guide position after the injection unit moves to the standby position,

the guide plate moves to the retreat position before the injection unit moves to the injection position.