JP2695762B2 - Device for detecting metal fragments in resin material and injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for supplying a granular resin material from a material hopper to a heating cylinder of a resin molding machine such as an injection molding machine or an extrusion molding machine, or for transferring the material to a predetermined place. The present invention relates to an apparatus for detecting a metal piece in a resin material for detecting a metal piece mixed in a feed passage, and an injection molding machine provided with the metal piece detection apparatus.

[0002]

2. Description of the Related Art In plastic molding, when molding is performed with metal pieces mixed in a molding material, the metal pieces are clogged in a nozzle of a molding machine and cannot be molded, or the metal pieces pass through the nozzle and are embedded in a molded product. Problems arise. Especially,
In the injection molding of industrial plastics, the hardness of the industrial plastics is high, so that the pulverizer is liable to be spilled. If the metal piece is molded while being mixed with the resin material, the metal piece bites into the molten resin check valve disposed at the end of the heating cylinder of the injection molding machine, and molding becomes impossible. In this case, wait until the resin in the heating cylinder cools down, remove the check ring from the heating cylinder, and remove the clogged metal pieces. Had been significantly reduced.

[0003] In order to prevent the metal pieces from being mixed, there is known an apparatus utilizing a metal sensor (4) as follows. As shown in FIG. 4, the material hopper is located vertically above the material supply side of the heating cylinder (92) in the molding machine.
(90) is provided, and the material hopper (90) and the heating cylinder (92) are connected through the transfer pipe (91). A metal sensor (4) is provided around the transport pipe (91), and below the sensor (4),
A metal discharge mechanism (93) such as a switchgear and a suction pump is provided. The sensor (4) and the discharging mechanism (93) are electrically connected via the amplifier (40) and the controller (42). The metal sensor (4) generates an oscillating magnetic field or a stationary magnetic field in the transport pipe (91) using a coil, and uses the coil or another coil to generate an electric field due to a change in impedance or induced voltage of the coil. Detect changes. Conveying pipe (91)
When a metal piece passes through the inside, the sensor (4) transmits a detection signal. The amplifier (40) amplifies the detection signal from the sensor (4) and sends it to the controller (42). Controller (4
2) controls the discharge mechanism (93) to transfer the metal pieces to the transport pipe (9).
Set to discharge from 1).

[0004]

However, in this apparatus, since the falling speed of the material is accelerated by gravity,
The longer the time delay between the detection of the metal sensor (4) and the activation of the metal discharge mechanism (93), the more
It is necessary to increase the distance H between (4) and the discharge mechanism (93), and the device becomes large. In addition, it is difficult to detect and remove a metal piece falling freely in the transport pipe (91) during a short time when the metal piece passes through the sensor (4) and the discharge mechanism (93). Operation was difficult.

The inventor of the present application has previously provided a helical shaft made of a non-magnetic material in a granular material feed passage, embedded a magnet in the helical shaft, and when the helical shaft sent the granular material, A device for adsorbing metal pieces to prevent the mixing of metal pieces was proposed (Japanese Utility Model Publication No. 4-35142). Although this device is excellent in preventing the mixing of metal pieces, it has the inconvenience of having to periodically pull out the helical shaft from the cylinder to check for the presence of metal pieces adsorbed by the magnet. .

[0006]

Means for Solving the Problems To solve the above problems,
The present invention is configured as follows. The cylinder has a material supply unit, a material discharge unit, and a detection unit. The detection unit is formed of a non-magnetic material, and is provided between the supply unit and the discharge unit. A helical shaft formed of a non-magnetic material is rotatably provided in the cylinder, and a rotation driving device is connected to the helical shaft. A metal sensor is provided on the outer periphery of the detection unit of the cylinder. The sensor generates an oscillating magnetic field or a steady magnetic field in the detection unit using a coil, and detects an electrical change of the coil using the coil or another coil. Further, at least one permanent magnet can be embedded in the shaft between the spiral blades on the spiral shaft on the side of the discharge unit or on the side of the supply unit remote from the detection unit. Further, an alarm may be electrically connected to the sensor, and the alarm may be set to be activated when the operation of the sensor detects that a metal piece is mixed in the resin material in the detection unit. Further, the sensor is electrically connected to a rotary drive device,
The rotation of the helical shaft can be set to stop when the detection of the incorporation of a metal piece in the resin material in the detection section by the operation of the sensor. Further, an opening / closing device is provided at a material discharge port of the discharging portion, and the opening / closing device is electrically connected to the sensor. When the operation of the sensor detects mixing of a metal piece into the resin material in the detection portion, the opening / closing device is provided. Can be set to close the material outlet.

[0007]

According to the present invention, the helical shaft is rotated by the rotary driving device, and the resin material is conveyed by the screw thrust generated by the rotation of the helical shaft. Then, an oscillating magnetic field or a steady magnetic field is generated in the detection unit by the metal sensor. At this time,
If a metal piece is mixed in the material, it appears as an electrical change due to a change in the impedance or induced voltage of the coil in the sensor, and by detecting this, the metal piece is mixed in the material in the detection unit. Is detected, the sensor outputs a detection signal by the detection. Since the material conveying speed by the helical shaft is determined by the rotation speed of the shaft and the blade angle, a constant speed other than high speed can be maintained.
Further, since the material can be conveyed densely by the helical shaft, the speed can be reduced. Therefore, reliable operation can be expected in the detection and discharge of the metal piece by the sensor and the elimination device. In order to generate a magnetic field in the resin material inside the detection unit that is sufficient for the metal sensor to detect a metal piece, the detection unit and the helical shaft of the cylinder are made of a non-magnetic material such as plastic, ceramic, or glass. Can be

Further, if a permanent magnet is embedded in the helical shaft on the side of the material discharge section remote from the detection section, the metal piece detected by the sensor can be surely attracted to the magnet, so that it is smaller than a conventional metal piece detection device. Can be realized. Also, if a permanent magnet is embedded in the helical shaft on the side of the material supply unit that is remote from the detection unit, the magnet will attract the metal piece before the sensor detects the metal piece, thereby reducing the number of times the sensor detects the metal piece. Work efficiency can be improved. If an alarm is used, a metal piece detection signal from the sensor is transmitted to the alarm, and the alarm notifies that the metal piece has been mixed. Therefore, it is more convenient than the conventional method of embedding the magnet in the helical shaft because the mixing of the metal pieces can be confirmed by the alarm. Also,
If a method of stopping the rotation drive device is used, the rotation drive device receives a metal piece detection signal from the sensor, stops rotation of the helical shaft, and interrupts material conveyance. Therefore, the metal piece can be reliably prevented from being sent to the heating cylinder, and the size can be reduced as compared with the conventional metal piece detection device. further,
If the switchgear provided at the material discharge port is used, the material discharge port is closed by the metal piece detection signal from the sensor,
The metal pieces can be more reliably prevented from being sent to the heating cylinder.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 2, in the injection molding machine, a heating cylinder (90) is provided between a conveying passage through which a material supplied from a material hopper (90) is sent to a heating cylinder (92).
In parallel with (92), the apparatus for detecting metal fragments in the resin material of the present invention (1)
Is deployed. The cylinder (2) of the device is
(6), a detection section (7) and a material discharge section (8).

As shown in FIG. 3, the material supply section (6) has a material supply port (60) at an upper portion thereof, and the material from the material hopper (90) is supplied to the cylinder (2) through the supply port (60). Supplied inside. The material discharge portion (8) has a through hole (8
0) is formed, and the through hole (80) communicates with the cylinder (2). The lower opening of the through hole (80) serves as a material discharge port (81) for discharging the material to the heating cylinder (92) through the transfer pipe (91). The upper opening (82) of the through hole (80) is closed by the upper lid (83). A valve body (84) is removably provided at a material discharge port (81), which is a lower opening of the through hole (80). Valve body (84)
Is controlled by the controller (42). A detection unit (7) is provided between the supply unit (6) and the emission unit (8), and generates a magnetic field sufficient to detect a metal piece in a feed passage (70) therein. And the detection unit (7)
Is made of a non-magnetic material such as plastic, ceramics, and glass. Supply unit (6) and discharge unit (8)
Is fixed and supported by the cylinder support (20) of FIG.

A metal sensor (4) is provided so as to surround the detecting section (7). The sensor (4) is the same as the sensor described in (Prior Art). The detection signal from the sensor (4) is transformed and amplified into an appropriate waveform by the amplifier (40), and the alarm (4) is output.
1) and transmitted to the controller (42).

A spiral shaft (3) is provided in the cylinder (2). The spiral shaft (3) has a single spiral blade (3) on the peripheral surface of the shaft portion (30).
1) is protruding. The shaft portion (30) of the spiral shaft (3) and the spiral blade (31) are made of a non-magnetic material such as plastic, ceramics, glass or the like, similar to the detecting portion (7). Helical shaft (3)
The permanent magnets (32a) and (32b) are attached to the shaft (30) between the spiral blades (31) on the material supply part (6) side and the material discharge part (8) side from the position of the sensor (4). Is buried. Material supply unit (6)
, The end of the helical shaft (3) penetrates a bearing (62) provided in the base opening (61) of the cylinder (2) so as to be able to be inserted and removed, and the joint (50) of the rotary drive device (5). ), And are engaged with each other in a rotatable and detachable manner. The rotation drive of the rotation drive device (5) is controlled by the controller (42). In the material discharging section (8), the end of the spiral shaft (3) is connected to the proximal opening (8) of the cylinder (2).
It is rotatably supported by a lid (86) arranged in 5) via a bearing (87). When the lid (86) is removed and the spiral shaft (3) is pulled out, the spiral shaft (3) is disengaged from the joint (50) of the rotary driving device (5), and the spiral shaft (3) is disengaged from the cylinder (2). ) Can be taken out.

The alarm (41) is set so as to generate an alarm by light or sound when receiving a detection signal from the amplifier (40). When receiving the detection signal from the amplifier (40), the controller (42) stops the rotation drive of the rotary drive device (5), and simultaneously makes the valve body (84) advance to the material discharge port (81), and The outlet (81) is set to close.

However, the helical shaft is driven by the rotary driving device (5).
When (3) is rotated, the resin material carried in from the material hopper (90) is forced into the cylinder (2) by the screw thrust of the spiral shaft (3).
From the supply section (6) to the discharge section (8) through the detection section (7), and is discharged from the material discharge port (81) to the heating cylinder (92) through the transfer pipe (91). Then, an oscillating magnetic field or a steady magnetic field is generated in the detection unit by the metal sensor (4). At this time, if metal pieces are mixed in the resin material,
When the metal piece enters the area of the detection section, the sensor (4) detects the mixing of the metal piece and outputs a detection signal. When the detection signal is amplified by the amplifier (40) and transmitted to the alarm (41) and the controller (42), the alarm (41) issues an alarm by light or sound, and the metal piece is output from the sensor (4). Discharge part (8)
The metal magnets (32b) are attracted to the heating cylinder (92) to prevent the metal pieces from entering the heating cylinder (92). At this time, the controller (42) stops the rotation drive of the rotary drive device (5),
By projecting (84) into the material discharge port (81) and closing the material discharge port (81), the mixed metal pieces can be reliably confined in the cylinder (2).

After the rotation of the rotary drive unit (5) is stopped, the lid (86) is removed, the spiral shaft (3) is pulled out, and the spiral shaft (3) is removed.
Attach to magnets (32a) (32b) embedded in
(2) It is sufficient to remove the metal pieces confined in the inside. After removing the metal pieces, the helical shaft (3) is returned into the cylinder (2), the lid (86) is attached, and the valve (84) is retracted to release the material discharge port (81).
, Release the alarm of the alarm (41), and
By restarting the rotation drive of (5), the material conveyance can be restarted. In addition, since the metal piece is attracted to the upstream magnet (32a), the number of times the rotary drive device (5) stops due to the passage of the metal piece as described above can be reduced, and the working efficiency can be increased.

When the industrial plastic is crushed, the ratio of the blade of the crusher spilled and mixed into the plastic material is about once a day. In addition, it is sufficient to prevent metal pieces from being mixed in the process. The spiral shaft (3) is made of a non-magnetic material only for the portion corresponding to the detection unit (7), instead of being formed entirely of a non-magnetic material, and the material supply unit side and the material discharge unit side are made of a metal material. These may be integrally connected to form a single spiral shaft (3). Further, by forming the detection unit (7) and the helical shaft (3) from a non-magnetic and insulating material such as plastic, the detection unit (7) and the helical shaft (3) are connected to the sensor (4). )
And the sensor (4) can detect the metal piece with high accuracy. Further, since the magnets (32a) and (32b) embedded in the helical shaft (3) also rotate by the rotation of the helical shaft (3), the rotation of the helical shaft (3) does not affect the sensor (4). Are preferably arranged rotationally symmetrically with respect to the rotation axis of the helical axis (3). Further, the apparatus for detecting a metal piece in a resin material (1) of the present invention is not limited to a method of transporting a resin material from a material hopper (90) to a heating cylinder (92) of an injection molding machine. The present invention can be used for any device that needs to remove metal pieces mixed in the material during the transportation of the material.

When the metal piece detecting device (1) of the present invention is not used, a material hopper (90) is provided in the upper opening (82) of the through hole (80), and the opening of the cylinder (2) is closed. By closing with a lid or the like, the resin material can be supplied directly from the material hopper (90) to the heating cylinder (92).

The description of the above embodiment is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. or,
The configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a device for detecting a metal piece in a resin material of the present invention.

FIG. 2 is a sectional view of a main part showing an embodiment of the present invention.

FIG. 3 is an enlarged view of a main part of FIG. 2;

FIG. 4 is a sectional view showing a conventional device for detecting a metal piece in a resin material.

[Explanation of symbols]

 (2) Cylinder (3) Helical shaft (4) Metal sensor (5) Rotary drive (6) Cylinder material supply section (7) Cylinder detection section (8) Cylinder material discharge section

Claims (6)

(57) [Claims] 1. A material supply part (6) at one end, a material discharge part (8) at the other end, and a detection part formed of a non-magnetic material between the supply part (6) and the discharge part (8). Cylinder with (7) (2)
Inside, a helical shaft (3) formed of a non-magnetic material is rotatably provided, and a rotary drive (5) is connected to the helical shaft (3), and a detection unit (7) of the cylinder (2) is provided. A metal sensor (4) for generating an oscillating magnetic field or a stationary magnetic field in the detecting section (7) using a coil and using the coil or another coil to detect an electrical change of the coil on the outer periphery of the coil. A device for detecting metal fragments in the deployed resin material. 2. A material supply part (6) at one end, a material discharge part (8) at the other end, and a detection part formed of a non-magnetic material between the supply part (6) and the discharge part (8). Cylinder with (7) (2)
Inside, a helical shaft (3) formed of a non-magnetic material is rotatably provided, and a rotary drive (5) is connected to the helical shaft (3), and a detection unit (7) of the cylinder (2) is provided. A metal sensor (4) for generating an oscillating magnetic field or a stationary magnetic field in the detecting section (7) using a coil and using the coil or another coil to detect an electrical change of the coil on the outer periphery of the coil. Deploy and detect
At least one permanent magnet (32b) is attached to the shaft (30) between the spiral blades (31) of the spiral shaft (3) on the side of the discharge section (8) or the side of the supply section (6) away from (7). The apparatus for detecting a metal piece in a resin material according to claim 1, wherein (32a) is embedded. 3. An alarm (41) is electrically connected to the metal sensor (4), and the alarm (41) is activated by the operation of the sensor (4).
The apparatus for detecting a metal piece in a resin material according to claim 1 or 2, wherein the apparatus is operated. 4. The metal sensor (4) is electrically connected to the rotary driving device (5), and the detection unit is operated by the operation of the sensor (4).
The apparatus according to any one of claims 1 to 3, wherein the rotation of the helical shaft (3) is stopped when detecting the incorporation of a metal piece into the resin material in (7). 5. An opening / closing device (84) at a material discharge port (81) of a material discharging portion (8) of a cylinder (2), wherein the opening / closing device (84) is provided.
And the metal sensor (4) are electrically connected to each other. When the operation of the sensor (4) detects the incorporation of a metal piece into the resin material in the detection section (7), the opening / closing device (84) opens the material discharge port. The apparatus for detecting a metal piece in a resin material according to any one of claims 1 to 4, wherein (81) is closed. 6. A material hopper (90) of a resin molding machine is connected to a material supply port (60) of a material supply section (6) of a cylinder (2), and is connected to a material discharge section (8) of a cylinder (2). An injection molding machine equipped with a device for detecting a piece of metal in a resin material according to any one of claims 1 to 5, wherein the material discharge port (81) is connected to a heating cylinder (92) of the resin molding machine. .