JPH11170317A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely control all of injection timing, injection speed, a pressing speed, pressing pressure and the others by controlling all of the operations of injection work by a servo motor. SOLUTION: In an injection molding machine using servo motors 11, 12, 31, 40, 45 in the respective drive sources of the injection of a weighed resin into a mold cavity (2), the weighing of a kneaded resin, the opening and closing of a mold 1, the gate cutting after the filling of the mold cavity 2 with the weighed resin, the ejection of a molded product after molding and the taking-out of the molded product in an injection molding process, the gate cutting and the ejection of the molded product are performed by one servo motor 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine using a servomotor as each drive source in an injection molding process.
In particular, the present invention relates to an injection molding machine in which a gate cut and a molded product projecting process are performed by a single servomotor.

[0002]

2. Description of the Related Art Injection molding machines using a servomotor as a drive source for each step are already widely used at present. However, if one servo motor is used for all the operating mechanisms, the number of servo motors is too large, which not only increases the equipment cost but also complicates the control.

[0003]

SUMMARY OF THE INVENTION The present invention aims at reducing the manufacturing cost of the apparatus and simplifying the control without lowering the performance by performing the gate cutting and the molded article protruding step with a single servomotor. Is the solution.

[0004]

Means for Solving the Problems Claim 1 achieves the above-mentioned object. In the injection molding step, injection of a measuring resin into a mold cavity (2), measurement of a kneading resin, and a mold (1 )
Servo motors (11), (12), (31), and (40) for each drive source for opening / closing the mold, cutting the gate after filling the resin into the mold cavity (2), projecting the molded product after molding, and removing the molded product And (45)
An injection molding machine characterized in that the gate cut and the molded product ejection are driven by one servomotor (40).

According to this, since all operations of the injection work are controlled by the servo motors (11), (12), (31), (40) and (45), the timing, injection speed, pressurization speed, You can freely control the pressurizing pressure and everything else,
Not only can the transferability of the fine irregularities engraved in the mold cavity (2) to the molded product (26) be significantly improved, but also the servomotors (11) (12) (31) (40) and ( 45) The compound operation can be performed, so the cycle can be increased, and the gate cut and the protrusion of the molded product can be performed by one servo motor.
Since the drive is performed in (40), the number of servomotors can be reduced without lowering the device performance, and the control can be simplified.

[0006] The injection molding machine (A) of "claim 2" is claim 1
In a further specific example, in an injection molding machine that drives gate cut and protrusion of a molded product by one servo motor (40), a screw mechanism (G) for gate cut driving a gate cut member (30) and a molded product ( The ejecting screw mechanism (E) for driving the ejecting member (27) of (26) is driven by the same servomotor (40), and the screw portions (27a) (30a) of both mechanisms (G) and (E) are connected. Are configured with mutually opposite screws ”.

[0007] According to this, the gate cut member (30) and the eject member (27) can be obtained simply by changing the rotation direction of one servomotor (40) from normal rotation to reverse rotation or from reverse rotation to normal rotation.
Can be controlled.

A third aspect of the present invention relates to a specific example of the injection molding machine (A) of the present invention, which comprises "a hollow gate cut member (30) and an eject member (27) slidably inserted into the gate cut member (30). ), A gate cut drive nut (44) that is screwed into the threaded portion (30a) of the gate cut member (30) to advance and retract the gate cut member (30), and an eject member (27). The eject nut (4) is screwed into the screw (27a) of the eject member (27) to advance and retract the eject member (27).
9) and a pulley (43) for simultaneously rotating the gate cut drive nut portion (44) and the eject nut portion (49), and the gate cut drive nut portion (44) and the eject nut portion (49). ) Are oppositely screwed to each other.]

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. The injection molding machine (A) of the present invention is roughly divided into an injection mechanism (a) and a mold mechanism (b) as shown in FIG. The injection mechanism (a) includes a drive mechanism (10) for moving the screw (4) forward and backward, a rotation servomotor (11) for rotating the screw (4), and moving the screw (4) forward and backward. Servo motor for injection (12), screw for kneading and injection of raw resin
(4), an injection cylinder (13) in which the screw (4) is retractable and rotatable, and a heater (1) wound around the injection cylinder (13).
4), disposed between the screw (4) and the drive mechanism (10),
The load cell for injection (15) that detects the pressure applied to the screw (4), the raw material supply hopper (16), and each servo motor (1
1) A pulse generator (11a) (12a) mounted on (12).

Next, the mold mechanism (b) will be described. The mold (1) is composed of a movable / fixed mold (1a) (1b), the fixed mold (1a) is mounted on the fixed die plate (17), and the movable mold is mounted on the movable die plate (18). (1b) is mounted, and a housing (50) is mounted on a movable die plate (18) via a pressure sensor (7) on the opposite side of the movable mold (1b).
The back of the housing (50) (ie opposite the moving mold (1b))
In the center, a gate cut screw mechanism (G) is provided, and behind it is provided an eject screw mechanism (E) integrally with the gate cut screw mechanism (G). The feature of the present invention is that the servo motor (40) performs gate cutting and molded product projection, and this portion will be described in detail below. A tie bar (19) is provided between the fixed die plate (17) and a tailstock (20) described later, and the movable die plate (18) is slidably mounted on the tie bar (19).

Next, a gate cutting screw mechanism (G) and an eject screw mechanism formed in the housing (50).
(E) will be described. A rotary housing (50a) is disposed in the housing (50) via a bearing, and a driven pulley (4) is provided at a protruding end of the rotary housing (50a).
3) is fixed, and the gate cut drive nut part (44) is fixed in the hollow part (50b) of the rotating housing (50a). The gate cut drive nut (44) is screwed with a hollow threaded portion (30a) so that the gate cut drive nut (44) moves forward and backward by rotation of the gate cut drive nut (44). A hollow threaded portion (30a) is screwed at the center of the threaded portion, so that the threaded portion (30a) moves forward and backward in accordance with the forward and reverse rotation of the driven pulley (43). A hollow gate cut pin (30b) is arranged on the movable mold (1b) in accordance with the hollow screw portion (30a). A center pin (27c) is slidably disposed in the gate cut pin (30b).

The driven pulley (43) is connected to a drive pulley (41) of a servo motor (40) via a timing belt (42). The gate cut member (30) is operated by the servo motor (40). Here, the gate cut member (30) is composed of a hollow screw portion (30a) and a gate cut pin (30b) attached to the tip thereof. (40a) is a pulse generator mounted on the servomotor (40).

To explain the eject screw mechanism (E), a straight portion (27b) of an eject member (27) is rotatably and slidably inserted into the hollow screw portion (30a). The screw portion (27a) of the eject member (27) is screwed into an eject nut portion (49) mounted inside the protruding end of the rotary housing (50a). Therefore, in the case of the structure of the present embodiment, the ejection member (27) is
7a), its straight portion (27b), and center pin (27c).

A connecting bar is provided at the end of the screw portion (27a).
(39) is attached and the nut is fixed. Guide bars (37) are attached to both ends of the connection bar (39), and guide holes (3) formed in the housing (50) are provided.
8) It is slidably arranged. As described later, when projecting the molded product (26), first, the gate portion (26a) attached to the tip of the center pin (27c) is dropped first, and then the molded product (26) is moved. It will be detached from the mold (1b).

Next, the mold opening / closing toggle mechanism (T) will be described. The tailstock (20) has a die control servomotor (3
1) is mounted, and its rotary drive shaft has a drive pulley
(32) is attached. In addition, tailstock (20)
A toggle drive nut part (51) is rotatably arranged inside the bearing via a bearing, and a driven pulley (34)
Is mounted, and a toggle actuating screw (34a) is threadably mounted on the toggle drive nut (51) so as to advance and retreat. The drive pulley (32) and the driven pulley (34) are connected via a timing belt (33), and transmit the torque of the servomotor (31) to the driven pulley (34). A pulse generator (31a) is mounted on the mold control servomotor (31).

The torque transmitted to the driven pulley (34) is transmitted to the screw portion (34a) via the toggle drive nut portion (51), and is movable forward and backward in accordance with the rotation of the toggle drive nut portion (51). The projecting end of the screw portion (34a) is attached to the mold opening / closing crosshead (35). The mold opening / closing toggle connects each of the long and short arms (36) to a link mechanism, one end of which is rotatably connected to the tailstock (20) and the other end is rotatably connected to the housing (50). The other end is attached to the mold opening / closing crosshead (35). Since this link mechanism is a known technique, further details will be omitted.

Next, the product take-out device (S) will be described.
The servo motor (45) of the product take-out device (S) is installed on the movable die plate (18), and in this embodiment, the product take-out arm (4) is provided via an actuator (46) constituted by a cylinder.
7) is attached, and a suction pad (48) is provided at the tip thereof. Further, a pulse generator (45a) is provided at the rear end of the servo motor (45), and the servo motor (45)
It controls the rotation angle and angular velocity.

Here, since the reciprocating working distance of the actuator (46) operating for taking out the molded product (26) is short, a cylinder is sufficient, but a servomotor can also be used. When a servo motor is used, the take-out timing can be completely matched so that the loss time can be reduced to zero.However, when a cylinder is used, the response time is inferior to the servo motor and a slight loss time can occur. There is. However, since the working distance is sufficiently short, the performance of the present apparatus is not impaired.

A control device (8) controls the overall operation of the injection molding machine (A). One of the functions is a load cell for injection (15), a pressure sensor (7), a servo motor, and the like. (1
1) The pulse generator (1) attached to (12), (31), (40) and (45)
1a) (12a) (31a) (40a) and signals from (45a) and other signals are obtained and servo motors (11) (12) (31) (40) and (45) and other controls are performed. It has become. Since all control of the drive system is performed by the servomotor, arbitrary conditions such as a composite operation can be created by programming. (9) is an input / output device for the control device (8) and a CRT.

Next, the operation of the present invention will be described. The raw material resin (3c) is charged into the raw material supply hopper (16), and when the screw (4) is rotated by operating the rotation servomotor (11), the raw material resin (3c) is gradually fed toward the injection cylinder (13). Since the injection cylinder (13) is heated by a heater (14) wound around its outer periphery, the injection cylinder (13) is
(13) The raw material resin (3c) entered gradually melts and
It is kneaded by the rotating action of (4).

With the rotation of the screw (4), the melt-kneaded resin (3
b) is sent toward the tip of the injection cylinder (13), and is stored at the tip. As a result of this reaction, the screw (4) gradually retreats, and eventually reaches a preset retreat stop position. At this point, the resin measurement has been completed. continue,
The rotary servomotor (11) is stopped and the injection servomotor (12) is operated to push the screw (4) forward, and the metered molten kneading resin (3a) accumulated at the tip of the injection cylinder (13) Is injected into the mold cavity (2).

On the other hand, on the mold (1) side, the mold is firstly clamped as shown in FIG. That is, the mold control servomotor (3
1) to transmit its rotational force to the driven pulley (34) via the driving pulley (32) and the transmission belt (33), and
When (4) is rotated, the screw portion (34a) screwed into the toggle drive nut portion (51) advances rightward in the drawing, and the crosshead (3
Push the mold open / close toggle (T) by pushing 5). At this time, the moving die plate (18) and the moving mold (1a) attached thereto move to the fixed mold (1b) side in accordance with the extension, and the moving mold (1a) is moved to the fixed mold (1b). ) Is pressed at a predetermined pressure to perform mold clamping.

Next, in this state, the injection servomotor (12) is operated to operate the screw mechanism (10),
(4) is moved to the mold (1) side, and the metering and kneading molten resin (3a) at the tip of the injection cylinder (13) is injected into the mold cavity (2). The injection speed is optimally controlled by the control device (8). When the measured molten resin (3) is injected and filled into the mold cavity (2), a gate cut is performed subsequently.

That is, when the servo motor (40) is operated while the mold (1) is being clamped after the above-described resin filling, the drive pulley (41) rotates and the timing belt (42) is moved. The driven pulley (43) rotates via the driven pulley. Since the driven pulley (43) is screwed to the hollow screw portion (30a) via the rotary housing (50a) and the gate cut drive nut (44), the hollow screw is rotated by the rotation of the driven pulley (43). Section (30a) moves forward,
Connect the gate cut pin (30b) connected to this to the gate (1
Protrude toward c) and cut the gate.

On the other hand, the screw portion (27a) of the eject member (27)
Is screwed to the eject nut (49), so that when the driven pulley (43) rotates, the eject nut (49)
Also, since the screw part (27a) of the eject member (27) and the hollow screw part (30a) are formed as reverse screws, the hollow screw part (30a) is formed as described above. When the eject member 27 moves forward, the eject member 27 retreats. When the gate cut is completed in this way, the mold cavity (2) is completely shut out from the outside.

As described above, when the gate cut is completed, the mold clamping state is maintained or further tightened in this state, and the filling resin (3) is pressed with an extremely strong pressure, and the mold on the moving mold (1b) side is pressed. The fine irregularities formed on the inner peripheral surface of the mold cavity (2) are transferred to the curing filling resin (3). (See Fig. 3)

When the curing of the filling resin (3) is completed, the servo motor (31) is operated in reverse to loosen the toggle mechanism (T) to separate the movable mold (1b) from the fixed mold (1a) side. At this time, the molded product (26) moves together with the movable mold (1b) while being fitted into the mold cavity (2) of the movable mold (1b). (See Fig. 4)

Finally, when the mold opening is completed, the servo motor
Reverse (40). Then, the hollow screw part (30a) and the gate cut pin (30b) connected to it retreat and the molded product
At the same time, the eject member (27) moves away from (26) and advances to drop the gate portion (26a) attached to the tip of the gate cut pin (30b). (See Fig. 5)

Subsequently, for example, a compressed gas is press-fitted between the cavity (2) of the movable mold (1b) and the molded product (26) to slightly float the molded product (26) from the cavity (2). (See Fig. 6)
Although not shown, the molded product (26) may be slightly lifted from the cavity (2) by using a separately prepared projection pin.

Then, the product take-out device (S) is operated at the above-mentioned separation timing. << When the molded product (26) is protruded with the protruding pin (not shown) as described above,
Since the protrusion pins are controlled by the servomotor (40), the reproducibility of the timing has extremely high accuracy. Since the operation of the servo motor (40) is sequentially input to the control device (8), it is possible to operate the servo motor (45) of the product unloading device (S) in accordance with the movement of the servo motor (40). it can.

On the other hand, on the side of the product unloading device (S), which has been waiting outside the mold (1), the arm (47) is rotated by a certain angle so that the leading end of the arm (47) is positioned within the parting surface of the mold (1). Insert
After stopping in front of the molded product (26), the actuator (46)
To move the suction pad (48) of the arm (47) to the molded product (26).
Moved toward the side, the protruding part (26) or the part at the moment of or at the moment of protruding
(26), and then the actuator (46) is reversely operated to release the molded product (26) from the mold cavity (2), and then the servomotor (45) is reversely operated to form the molded product ( 26) The mold
(1) Take it out. This series of operations is performed from 0.12 to 0.15.
Performed in seconds, the loss time in a series of operations from eject to product removal is minimized, contributing to an improvement in cycle up.

[0032]

As described above, according to the present invention, since all operations of the injection work are controlled by the servomotor, it is possible to freely control the timing, injection speed, pressurizing speed, pressurizing pressure, etc. As a result, the cycle can be improved. In particular, by performing the gate cutting and the molded product protruding process with one servomotor, the manufacturing cost of the device can be reduced and the control can be simplified without lowering the performance. I was able to achieve it.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic structure of a part of an entire injection molding machine according to the present invention;

FIG. 2 is an enlarged sectional view of the mold mechanism of FIG. 1 at the time of mold clamping;

FIG. 3 is an enlarged cross-sectional view showing a state where the mold is being filled with resin in the mold mechanism of FIG. 2;

FIG. 4 is an enlarged sectional view of the mold mechanism of FIG. 2 when the mold is opened;

FIG. 5 is an enlarged cross-sectional view of the mold mechanism of FIG. 2 when a gate portion is protruded.

FIG. 6 is an enlarged cross-sectional view of the mold mechanism in FIG. 2 when a molded product is protruded.

FIG. 7 is an enlarged sectional view taken along line XX of FIG. 2;

[Explanation of symbols]

 (A)… Injection molding machine (a)… Injection mechanism (b)… Mold mechanism (G)… Screw mechanism for gate cut (E)… Screw mechanism for eject (1)… Mold (1a)… Fixed Mold (1b)… Movable mold (2)… Mold cavity (3)… Resin (3a)… Measuring resin (3b)… Kneading resin (3c)… Material resin (4)… Screw (8)… Control device (11) (12) (31) (40) (45)… Servo motor (26)… Molded product (27)… Eject member (27a)… Screw part of screw mechanism for eject (30)… Gate cut pin (30a) ): Screw part of screw mechanism for gate cut (43) (54): Driven pulley (43a) (54a): Nut part of driven pulley

Claims (3)

[Claims] In the injection molding step, a measuring resin is injected into a mold cavity, a kneading resin is measured, a mold is opened and closed, a gate is cut after filling the measuring resin into the mold cavity, and a molded product after molding. An injection molding machine characterized by using a servomotor for each drive source for ejecting and removing a molded product, wherein the gate cut and the molded product ejection are driven by one servomotor. 2. An injection molding machine wherein a gate cut and a protrusion of a molded product are driven by a single servomotor. A screw mechanism for driving a gate cut member and an eject mechanism for driving an eject member of the molded product. An injection molding machine characterized in that the screw mechanism is driven by the same servomotor and the screws of both mechanisms are reverse screws. 3. A gate cutting drive for screwing a hollow gate cutting member, an ejecting member slidably inserted into the gate cutting member, and a threaded portion of the gate cutting member to advance and retreat the gate cutting member. A nut portion, an eject nut portion screwed to the eject member to advance and retreat the eject member, and a pulley for simultaneously rotating the gate cut drive nut portion and the eject nut portion. Injection molding machine characterized in that the part and the eject nut part have opposite threads.