TWI626141B - Injection molding apparatus - Google Patents

Abstract

An injection molding machine prevents breakage of the mold and shortens the cycle time of injection molding. The mold clamping device 4 moves the movable mold 31 from the mold opening position A to the mold clamping position B by elongating the piston rod 48 of the mold clamping cylinder 45. The deceleration start position C is set closer to the mold opening position A than the mold clamping position B. The mold clamping device 4 moves the movable mold 31 from the mold opening position A toward the deceleration start position C at a high speed. When the movable mold 31 is located at the deceleration start position C, the moving speed of the movable mold 31 is decelerated.

Description

Injection molding machine

The present invention relates to an injection molding machine for injecting molten material into a mold.

Patent Document 1 discloses an injection molding machine.

The injection molding machine includes a stationary mold, a movable mold, and a mold cylinder that moves the movable mold to a mold clamping position and a mold opening position. The mold clamping cylinder moves the movable mold to the clamping position by elongating the piston rod. Further, the mold clamping cylinder moves the movable mold to the mold opening position by contracting the piston rod. At the time of mold clamping, the clamping cylinder causes the stroke of the piston rod to be fixed to shorten the cycle time of the injection molding.

[Prior Art Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Publication No. 64-1061

Injection molding machine When the thickness of the mold changes due to the replacement of the mold, the movable mold The position of the clamping is changed. The mold clamping cylinder of the conventional injection molding machine is fixed at any position by a screw. Moreover, the position of the mold clamping cylinder can be displaced in the moving direction of the movable mold by loosening the screw. Thereby, when the thickness of the mold is changed, the position of the mold clamping cylinder is displaced without adjusting the stroke amount of the piston rod, so that the mold clamping cylinder stops the movable mold accurately at the mold clamping position.

Therefore, in the conventional injection molding machine, when the mold is replaced with a mold having a different thickness, the position of the mold clamping cylinder must be shifted, which is troublesome and labor-intensive.

Further, in the conventional injection molding machine, the expansion and contraction of the piston rod of the mold clamping cylinder are repeated, and the screw of the fixed mold clamping cylinder is sometimes loosened. In this case, the mold clamping cylinder is displaced during the mold clamping operation and cannot be correctly clamped.

The present invention has been made in view of the above problems, and an object thereof is to provide an injection molding machine which can shorten a cycle time of injection molding in a state in which a mold clamping cylinder has been fixed, and can prevent a mold from being damaged.

The injection molding machine of the present invention is characterized in that: the fixed mold 30; the movable mold 31, can be displaced to the mold opening position A from the fixed mold 30, and the mold clamping position B in contact with the fixed mold 30; And the mold clamping device 4 moves the movable mold 31 from the mold opening position A toward the mold clamping position B; and a deceleration start position C is set closer to the mold opening position A than the mold clamping position B, the injection The molding machine includes: a control device 10 that shifts the mode-locking speed of the mold clamping device 4; and a detecting unit 20 and a detecting unit 50 that detects that the movable mold 31 moves to the deceleration start position C; the mold clamping device 4 Slowly opening the movable mold 31 from the mold opening position A The start position C moves, and when the movable mold 31 is located at the deceleration start position C, the moving speed of the movable mold 31 is decelerated.

In the injection molding machine of the present invention, the mold clamping device 4 includes a mold clamping cylinder 45 including a piston rod 48 elongated in a mold clamping direction, and the control device 10 is located at the movable mold 31 The deceleration start position C decelerates the elongation speed of the piston rod 48.

If it is constructed in this way, the cycle time of injection molding can be made shorter.

In the injection molding machine of the present invention, the detecting unit includes a stroke detecting unit 20 that detects a stroke amount when the piston rod 48 is extended, and the control device 10 can detect the detected amount according to the detected stroke amount. The movable mold 31 is moved to the deceleration start position C.

In the injection molding machine of the present invention, the detecting unit includes a speed detecting unit 50 that detects an elongation speed of the piston rod 48, and the control device 10 can be based on an elapsed time from the start of the mold clamping, and The detected elongation speed is detected, and the movable mold 31 is detected to move to the deceleration start position C.

According to the present invention, the injection molding machine 1 moves the movable mold 31 to the deceleration start position C at a high speed when the movable mold 31 is clamped, so that the cycle time of the injection molding can be shortened. Further, the movable mold 31 is moved to the mold clamping position B while being decelerated, so that the mold is not damaged. Further, even when the thickness of the mold changes due to the replacement of the mold, the injection molding machine 1 can shorten the cycle time of the injection molding without changing the deceleration start position C, and the mold is not damaged.

1‧‧‧Injection molding machine

2‧‧‧Frame

3‧‧‧Mold

4‧‧‧Clamping device

5‧‧‧Injection device 5

10‧‧‧Control device

20‧‧‧Travel detection unit (detection unit)

21‧‧‧ pole

22‧‧‧Encoder

22a‧‧‧Rotating Department

23‧‧‧ Roller

30‧‧‧Fixed mould

30a‧‧‧Mold joint

31‧‧‧ movable mold

41‧‧‧1st fixed disk

42‧‧‧2nd fixed disk

43‧‧‧ lever

44‧‧‧ movable plate

45‧‧‧Clock cylinder

46‧‧‧Cylinder

46a‧‧‧Extension room

46b‧‧‧Shrinking room

47‧‧‧Piston

48‧‧‧ piston rod

50‧‧‧Speed detection unit (detection unit)

A‧‧‧Opening position

B‧‧‧Molding position

C‧‧‧Deceleration start position

H‧‧‧thickness

L‧‧‧ prescribed distance

Fig. 1 is a front view showing an embodiment of an injection molding machine of the present invention.

Fig. 2 is an explanatory view showing a control device of a mold clamping cylinder;

3 is an explanatory view showing a second embodiment of the detecting device.

As shown in Fig. 1, the injection molding machine 1 of the present invention comprises a frame 2, a mold 3, a mold clamping device 4, and an injection device 5. The mold 3, the mold clamping device 4, and the injection device 5 are disposed on the upper surface of the frame 2.

The mold 3 includes a fixed mold 30 and a movable mold 31. The fixed mold 30 is attached to the first fixed disk 41 of the above-described mold clamping device 4. The movable mold 31 is attached to the movable plate 44 of the above-described mold clamping device 4. The fixed mold 30 is disposed opposite to the movable mold 31 in the longitudinal direction of the frame 2.

The mold clamping device 4 includes a first fixed disk 41, a second fixed disk 42, a plurality of tie rods 43, and a movable disk 44. The first fixed disk 41 and the second fixed disk 42 are disposed apart from each other in the longitudinal direction of the frame 2. Further, the first fixed disk 41 and the second fixed disk 42 are fixed to the upper surface of the frame 2. The plurality of tie rods 43 are disposed between the first fixed disk 41 and the second fixed disk 42. Each of the tie rods 43 extends in parallel with the longitudinal direction of the frame 2. The movable plate 44 is movable along the tie rod 43 in the direction toward the first fixed disk 41 and in the direction away from the first fixed disk 41. That is, the movable mold 31 can be displaced by the movable disk 44 to be displaced to the mold opening position A from the fixed mold 30 and the mold clamping position B in contact with the fixed mold 30.

In addition, the clamping device 4 includes a clamping cylinder 45. Clamping cylinder 45 installation In the second fixed disk 42. The mold clamping cylinder 45 includes a cylinder tube 46, a piston 47 slidably disposed in the cylinder barrel 46, and a piston rod 48 coupled to the piston 47. The piston rod 48 protrudes from the cylinder bore 46.

The piston rod 48 expands and contracts in a direction parallel to the longitudinal direction of the tie rod 43. The cylinder bore 46 includes an expansion chamber 46a and a contraction chamber 46b. The expansion chamber 46a and the contraction chamber 46b are disposed with the piston 47 interposed therebetween in the longitudinal direction of the cylinder bore 46. The mold clamping cylinder 4 presses the piston 47 toward the longitudinal direction of the cylinder bore 46 by supplying pressure oil to the expansion chamber 46a, whereby the piston rod 48 is extended. Further, the mold clamping cylinder 45 presses the piston 47 to the other side in the longitudinal direction of the cylinder bore 46 by supplying the pressurized oil to the contraction chamber 46b, whereby the piston rod 48 contracts.

The piston rod 48 is coupled to the movable plate 44. When the piston rod 48 is extended, the movable platen 44 moves in the direction approaching the first fixed disk 41, whereby the movable mold 31 moves toward the direction close to the fixed mold 30, that is, in the mold clamping direction. The elongation of the piston rod 48 is the mold clamping action of the clamping device 4. Further, when the piston rod 48 contracts, the movable platen 44 moves in a direction away from the first fixed disk 41. That is, the movable mold 31 moves in the direction away from the fixed mold 30, that is, in the mold opening direction. The contraction of the piston rod 48 is the mold opening of the mold clamping device 4.

The injection device 5 is disposed adjacent to the first fixed disk 41 and is fixed to the upper surface of the frame 2. The injection device 5 ejects the molten material into the mold 3. The injection molding machine 1 shown in Fig. 1 is a die casting machine in which the injection device 5 ejects molten metal into the mold 3. Further, the injection molding machine 1 may be a resin injection molding machine in which the injection device 5 ejects molten resin into the mold 3.

The mold clamping time of the injection molding machine 1 is the time until the movable mold 31 moves from the mold opening position A to the mold clamping position B to return to the mold opening position A again. The cycle time of molding. In order to shorten the cycle time of the injection molding, the movable mold 31 may be moved from the mold opening position A to the mold clamping position B at a high speed. However, if the movable mold 31 moves to the mold clamping position B at a high speed, it will collide with the fixed mold 30. Thereby, the movable mold 31 and the fixed mold 30 are broken.

The fixed mold 30 and the movable mold 31 are mold-locked by elongating the piston rod 48 of the mold clamping cylinder 45. Therefore, the mode-locking speed of the mold clamping device 4 is the elongation speed of the piston rod 48. The elongation speed of the piston rod 48 is controllably controlled by the control device 10 described below. That is, the piston rod 48 is controlled such that the piston rod 48 is elongated at a predetermined speed and then decelerated from a predetermined speed. Further, the control device 10 can also control the elongation speed by shifting the speed to the first speed and the second speed. In this case, the piston rod 48 is controlled such that the piston rod 48 is decelerated to a second speed at a speed lower than the first speed and then at a second speed after being extended at the first speed.

The injection molding machine 1 of the present invention sets the deceleration start position C of the movable mold 31 in advance before the mold clamping operation of the mold clamping device 4. The deceleration start position C is set closer to the mold opening position A than the mold clamping position B. That is, the deceleration start position C is a position away from the mold clamping position B by a predetermined distance L. The predetermined distance L is a distance during which the movable mold 31 moves during deceleration from the start of the movable mold 31 to the stop. The predetermined distance L is determined according to the speed at which the movable mold 31 moves, for example, the first speed.

When the thickness of the mold changes due to the replacement of the mold, the deceleration start position C is reset according to the thickness H of the fixed mold 30. In this case, if the speed at which the movable mold 31 moves is the same, the deceleration start position C is determined by the thickness H of the fixed mold 30. In other words, the deceleration start position C can be set based on the mold joint surface 30a of the fixed mold 30.

The injection molding machine 1 of the present invention controls the mode-locking speed of the mold clamping device 4 in the following manner. The mold clamping device 4 elongates the piston rod 48 of the mold clamping cylinder 45 by moving the movable mold 31 from the mold opening position A to the mold clamping position B. First, when the movable mold 31 moves from the mold opening position A toward the deceleration start position C, the piston rod 48 is elongated at the first speed. Thereby, the movable mold 31 moves at a high speed. Next, when the movable mold 31 is at the deceleration start position C, the piston rod 48 is decelerated from the first speed. Thereby, the movement of the movable mold 31 is decelerated. Then, the piston rod 48 completes deceleration while the movable mold 31 reaches the mold clamping position B from the deceleration start position C.

Thereby, the injection molding machine 1 moves from the mold opening position A to the mold clamping position B in a short time by the movable mold 31, so that the cycle time of the injection molding can be shortened. Further, since the injection molding machine 1 does not collide with the fixed mold 30 because of the movable mold 31, it is possible to prevent breakage of the mold.

Next, the control device 10 for expanding and contracting the piston rod 48 of the mold clamping cylinder 45 will be described. As shown in FIG. 2, the control device 10 includes: an oil hydraulic pump 11; an operating valve 12, the pressure oil discharged from the hydraulic pump 11 is supplied to the expansion chamber 46a or the contraction chamber 46b of the mold clamping cylinder 45; a flow control valve 13; and a controller (controller) 14. The hydraulic pump 11 is rotationally driven by a motor 15. When the movable mold 31 is at the mold opening position A, the operation valve 12 is maintained at the neutral position N. Then, when the first solenoid 12a is energized, the operation valve 12 is switched to the extended position a. Further, when the second solenoid 12b is energized, the operation valve 12 is switched to the contraction position b.

When the operation valve 12 is at the neutral position N, the pressurized oil discharged from the hydraulic pump 11 is returned to the tank 16. At this time, the pressurized oil discharged from the hydraulic pump 11 is not supplied to the expansion chamber 46a and the contraction chamber 46b. Thereby, the piston rod 48 is stopped. In operation When the valve 12 is at the extended position a, the pressurized oil discharged from the hydraulic pump 11 is supplied to the expansion chamber 46a. At this time, the pressure oil of the contraction chamber 46b is returned to the oil tank 16. Thereby, the piston rod 48 is elongated. When the operation valve 12 is at the contraction position b, the pressure oil discharged from the hydraulic pump 11 is supplied to the contraction chamber 46b. At this time, the pressure oil of the expansion chamber 46a is returned to the oil tank 16. Thereby, the piston rod 48 is contracted and moved.

The flow rate control valve 13 controls the flow rate of the pressure oil discharged from the hydraulic pump 11 to the first flow rate and the second flow rate. The second flow rate is less than the first flow rate. That is, the flow rate control valve 13 increases or decreases the flow rate of the pressurized oil supplied to the operation valve 12. When the value of the current that energizes the solenoid 13a of the flow control valve 13 becomes large, the flow rate control valve 13 increases the flow rate supplied to the operation valve 12. Further, when the value of the current applied to the solenoid 13a of the flow control valve 13 becomes small, the flow rate control valve 13 reduces the flow rate supplied to the operation valve 12.

When the flow rate supplied to the operation valve 12 is increased, the moving speed of the piston rod 48 becomes faster. Further, when the flow rate supplied to the operation valve 12 is decreased, the moving speed of the piston rod 48 becomes slow. That is, the flow rate control valve 13 of the control device 10 is a unit that shifts the elongation speed of the piston rod 48, that is, the mold clamping operation speed of the mold clamping device 4.

When the mold opening signal is input to the controller 14, the controller 14 energizes the second solenoid 12b of the operation valve 12. Further, when a mode-lock signal is input to the controller 14, the controller 14 energizes the first solenoid 12a of the operation valve 12. Further, when the movable mold 31 is located at the deceleration start position C, the controller 14 switches the value of the current applied to the solenoid 13a of the flow rate control valve 13 from the first current value that was previously energized to the second current value. The second current value is smaller than the first current value. The deceleration start position C is stored in the controller 14. The deceleration start position C can be arbitrarily set.

Next, it is detected that the movable mold 31 is moved to the deceleration start position C. The first embodiment of the detecting unit will be described. As shown in FIG. 2, the detecting unit is a stroke detecting unit 20 that detects the stroke amount (moving distance) of the piston rod 48 of the mold clamping cylinder 45. As shown in FIG. 1, the stroke detecting unit 20 includes a rod 21 and an encoder 22. The rod 21 is supported by the second fixed disk 42 so as to move in the moving direction of the movable mold 31. The rod 21 is configured to be parallel to the tie rod 43. Further, one end of the rod 21 in the longitudinal direction is coupled to the movable platen 44. Thereby, the rod 21 moves together with the movable mold 31 in the moving direction of the movable mold 31.

The encoder 22 is mounted on the second fixed disk 42. The encoder 22 includes a rotating portion 22a. A roller 23 is mounted on the rotating portion 22a. The roller 23 is in contact with the surface of the rod 21. Thereby, the rotating portion 22a of the encoder 22 is rotated by the movement of the rod 21. Thereby, the encoder 22 detects the moving distance of the lever 21, that is, the stroke amount of the piston rod 48 of the mold clamping cylinder 45. Then, the encoder 22 outputs a detection signal based on the stroke amount of the piston rod 48. This detection signal is input to the controller 14.

The controller 14 detects at which of the mold opening position A, the mold clamping position B, and the deceleration start position C the movable mold 31 is based on the stroke amount of the piston rod 48. Further, the controller 14 may detect the object to be detected attached to the rod 21 by a sensor (not shown), and determine that the movable mold 31 is at a predetermined position. In this case, the sensor is preferably a sensor that detects the proximity of the object without contact like a proximity sensor or a displacement sensor.

Next, an operation of clamping the fixed mold 30 and the movable mold 31 to the mold clamping device 4 will be described. When the movable mold 31 moves from the mold opening position (A) toward the deceleration start position (C), the controller 14 energizes the first solenoid 12a of the operation valve 12. Thereby, the operation valve 12 is switched to the extended position a. Thereby, the pressurized oil discharged from the hydraulic pump 11 is supplied to the expansion chamber 46a of the mold clamping cylinder 45. At this point, the flow control The value of the current applied to the solenoid 13a of the valve 13 is the first current value. Further, the flow rate of the pressurized oil supplied to the expansion chamber 46a of the mold clamping cylinder 45 is the first flow rate. Thereby, the piston rod 48 is elongated at the first speed.

The stroke detecting unit 20 detects the stroke amount when the piston rod 48 is extended. The controller 14 detects that the movable mold 31 is located at the deceleration start position C based on the stroke amount of the piston rod 48 detected by the stroke detecting unit 20. Thereby, the controller 14 switches the value of the current that energizes the solenoid 13a of the flow control valve 13 to the second current value. Then, the flow rate control valve 13 switches the flow rate supplied to the operation valve 12 to the second flow rate. As a result, the piston rod 48 begins to decelerate.

The movable mold 31 is decelerated from the first speed by the piston rod 48, and is moved toward the mold clamping position B while being decelerated. That is, the movable mold 31 approaches the mold clamping position B at a speed lower than the first speed. At this time, since the movable mold 31 is in slow contact with the fixed mold 30, each mold is not damaged. Further, the movable mold 31 may approach the mold clamping position B at the second speed after the piston rod 48 is decelerated from the first speed to the second speed.

The controller 14 detects that the movable mold 31 is located at the mold clamping position B based on the stroke amount of the piston rod 48 detected by the stroke detecting unit 20. The controller 14 stops energization of the first solenoid 12a of the operation valve 12. Thereby, the operation valve 12 is switched to the neutral position N. Thereby, the piston rod 48 is stopped. Thereby, the movable mold 31 is stopped at the mold clamping position B.

Next, an operation of the mold clamping device 4 to mold the fixed mold 30 and the movable mold 31 will be described. When the movable mold 31 moves from the mold clamping position B toward the mold opening position A, the controller 14 energizes the second solenoid 12b of the operation valve 12. Thereby, the operation valve 12 is switched to the contraction position b. Thereby, the pressure oil discharged from the hydraulic pump 11 is It is supplied to the contraction chamber 46b of the mode locking cylinder 4. At this time, the value of the current applied to the solenoid 13a of the flow rate control valve 13 is the first current value. Further, the flow rate of the pressurized oil supplied to the expansion chamber 46a of the mold clamping cylinder 45 is the first flow rate. Thereby, the piston rod 48 contracts.

The stroke detecting unit 20 detects the amount of stroke when the piston rod 48 is contracted. The controller 14 detects that the movable mold 31 is located at the mold opening position A based on the stroke amount of the piston rod 48 detected by the stroke detecting unit 20. The controller 14 stops energization of the second solenoid 12b of the operation valve 12. Thereby, the operation valve 12 is switched to the neutral position N. Thereby, the piston rod 48 is stopped. Thereby, the movable mold 31 is stopped at the mold opening position A.

Next, a second embodiment in which the detecting unit that detects the movement of the movable mold 31 to the deceleration start position C will be described. As shown in FIG. 3, the detecting unit is a speed detecting unit 50 that detects the elongation speed of the piston rod 4. The speed detecting unit 50 outputs a detection signal based on the elongation speed of the piston rod 48. This detection signal is input to the controller 14.

The controller 14 measures the moving distance of the movable mold 31 based on the elapsed time from the start of the mold clamping and the elongation speed of the piston rod 48. When the moving distance of the movable mold 31 coincides with the distance from the mold opening position A to the deceleration start position C, the controller 14 detects that the movable mold 31 is located at the deceleration start position C.

The speed detecting unit 50 is a sensor that detects the flow rate of the pressure oil supplied to the expansion chamber 46a of the mode locking cylinder 45. The elongation speed of the piston rod 48 is detected based on the flow rate of the pressure oil detected by the sensor.

The controller 14 stores the deceleration start position C as a distance from the mold opening position A based on the mold opening position A. The controller 14 determines that the movable mold 31 moves when the moving distance of the movable mold 31 coincides with the stored distance. To the deceleration start position C.

The speed detecting unit 50 can also detect the elongation speed of the piston rod 48 based on the number of signals output per unit time by the encoder 22 of the stroke detecting unit 20.

The injection molding machine of the present invention is not limited to the embodiment. For example, the control device 10 may also be used instead of the flow control valve 13 to increase or decrease the flow rate of the pressurized oil by changing the rotational speed of the hydraulic pump 11. Further, the control device may also set the hydraulic pump 11 as a variable displacement pump. In addition, the detecting unit may also use a laser range finder that irradiates the movable mold 31 with a laser beam, and uses the reflected light of the laser beam to measure and move the mold. The distance between 31.

Claims (4)

An injection molding machine, comprising: a fixed mold (30); a movable mold (31), displaceable to a mold opening position (A) exiting from the fixed mold (30), and the fixed mold ( 30) a clamping position (B) of contact; and a clamping device (4) for moving the movable mold (31) from the mold opening position (A) toward the mold clamping position (B); The mold clamping position (B) is set closer to the mold opening position (A) with a deceleration start position (C), and the injection molding machine includes: a control device (10) for causing the mold clamping device (4) And the detecting unit (20, 50), the clamping device (4) comprises: a first fixed plate (41), the fixed mold (30) is mounted; and the second fixed plate (42) ) is disposed apart from the first fixed disk (41); the tie rod (43) is disposed between the first fixed disk (41) and the second fixed disk (42); and the movable disk (44) The movable mold (31) is attached and moved in a direction toward the first fixed disk (41) and a direction away from the first fixed disk (41) along the tie bar (43); The detecting unit (20, 50) comprises a rod (21) and an encoder (22), the rod ( 21) is disposed in parallel with the pull rod (43), moves together with the movable mold (31) in the moving direction of the movable mold (31), and is supported by the second fixed disc (42); An encoder (22) is mounted on the second fixed disk (42) and detects an action of the rod (21), thereby detecting that the movable mold (31) is located at the deceleration start position (C), the code The movable mold (31) and the movable mold (31) are located on opposite sides of the second fixed disc (42), and one end of the rod (21) in the longitudinal direction is coupled to the movable disc (44), and the other end is Extending through the second fixed disk (42) to the second fixed disk (42); the clamping device (4) moving the movable mold (31) from the mold opening position (A) Moving toward the deceleration start position (C), when the movable mold (31) is at the deceleration start position (C), the moving speed of the movable mold (31) is decelerated. The injection molding machine of claim 1, wherein the clamping device (4) comprises a clamping cylinder (45), the clamping cylinder (45) comprising a piston rod elongated in a clamping direction ( 48), the control device (10) decelerates the elongation speed of the piston rod (48) when the movable mold (31) is at the deceleration start position (C). The injection molding machine of claim 2, wherein the detecting unit comprises a stroke detecting unit (20), and the piston is detected by the encoder (22) detecting a moving distance of the rod (21) The amount of stroke when the rod (48) is extended, the control device (10) detects that the movable mold (31) is moved to the deceleration start position (C) based on the detected stroke amount. The injection molding machine of claim 2, wherein the detecting unit comprises a speed detecting unit (50) for detecting an elongation of the piston rod (48) by an output signal of the encoder (22) The speed, and the control device (10) detects that the movable mold (31) has moved to the deceleration start position (C) based on the elapsed time from the start of the mold clamping and the detected elongation speed.