JP2010105220A - Injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine improving the separation of a runner from a nozzle without being affected by a molding material and a molding condition. <P>SOLUTION: The injection molding machine includes a nozzle 26 injecting molten resins to molds 2 and 3, a runner-holding member 1 holding a runner 4 formed during injection molding, and a drive part 10 making the runner-holding member enter the molds and leave therefrom. After molding a molded article, the runner-holding member is moved on the approximately same plane as the discharge direction of the runner and in a direction different from the discharge direction, and then moved in the discharge direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injection molding machine, and more particularly to an injection molding machine with improved runner separation from a nozzle.

  Conventionally, in an injection molding machine that molds a molded product by injecting molten resin from a nozzle into a mold, the runner is formed by a runner holding means that is a runner lock member for the runner formed together with the molded product. What is known to discharge out of the mold when opening is known.

  In such an injection molding machine, a proposal as in Patent Document 1 has been made. The runner lock take-out bar in this document is synonymous with the above runner lock member or runner holding means.

  The separation of the nozzle and the runner in Patent Document 1 has been performed by the weight of the runner lock take-out bar and the frictional force at the runner shape portion formed on the runner lock take-out bar.

On the other hand, the injection molding machine described in Patent Document 2 includes means for urging the runner lock take-out bar in the mold opening direction. According to Patent Document 2, the runner lock take-out bar is pushed down by the ball plunger simultaneously with the mold opening operation of the mold, and the runner held by the runner lock take-out bar is separated from the nozzle by a pulling force that pulls away from the nozzle.
JP 2003-117950 A JP 2007-111977 A

  However, when molding is performed with a material containing a reinforcing agent typified by glass fiber or the like, the runner is firmly fixed to the nozzle, and the ball plunger as described above can obtain a sufficient urging force and stroke. Due to difficulties, the runner could not be separated from the nozzle, which was not always satisfactory. In addition, when the molding conditions are increased, specifically, for example, when the holding pressure is increased or the holding time is increased, the runner is likely to be firmly adhered to the nozzle. In some cases, it was impossible to separate.

  However, if a means other than a ball plunger such as an air cylinder is used to obtain a large urging force, there has been a problem that the apparatus itself becomes large.

  Accordingly, the present invention has been made in view of the above-described problems, and its object is to provide an injection molding machine that improves the separation of the runner from the nozzle without being affected by the molding material and molding conditions. is there.

  In order to solve the above-described problems and achieve the object, an injection molding machine according to the present invention includes a nozzle that injects a molten resin into a mold, a runner holding member that holds a runner formed during injection molding, Driving means for moving the runner holding member into and out of the mold, and after the molding operation of the molded product, the direction of discharging the runner holding member in substantially the same plane as the direction of discharging the runner. It is characterized by moving in a different direction and then moving in the discharging direction.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the injection molding machine which improves isolation | separation from the nozzle of a runner, without being influenced by a molding material and molding conditions.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of an injection molding machine provided with a runner discharge mechanism according to an embodiment of the present invention. 2 to 6 are views showing the configuration of the runner discharge mechanism of the injection molding machine in the present embodiment.

  First, in FIG. 1, for the mold clamping operation, the rotation of the mold clamping motor 31 is converted into a linear motion by the ball screw 32, and further converted into the vertical motion of the movable platen 7 by the toggle link mechanisms 33 and 34.

  FIG. 1 shows a state where mold clamping is completed, and the movable platen 7 is pressed against the fixed platen 9 with the intermediate plate 6 interposed therebetween. The mold movable side mold plate 35 fixed to the movable platen 7 with screws (not shown) is pressed against the fixed platen 9 together with the mold fixed side mold plate 2 fixed to the intermediate plate 6 with screws (not shown). Yes.

  At this time, the runner holding member 1 is pressed against the fixed platen 9 in a state of being fitted into the fixed-side template 2.

  Next, the rotation of the injection motor 36 is transmitted to the ball screw nut 38 via the belt 37.

  The resin pellets supplied from the material supply port 39 are melted in a cylinder (not shown) heated by the heater 40 and injected from the nozzle 26 into the mold by a plunger (not shown) connected to the ball screw nut 38 (injection). During molding) a molded product is formed.

  After cooling the molded product, the mold clamping motor 31 is rotated in the reverse direction, the movable platen 7 is lowered to perform the mold opening operation, and the molded product is taken out by a take-out mechanism (not shown).

  At this time, the intermediate plate 6 is lowered to a predetermined position and stopped. As the intermediate plate 6 is lowered, the runner holding member 1 is separated from the fixed-side mold plate 2, and the resin path of the fixed-side mold plate 2. The runner formed on is fixed to the runner holding member 1.

  By extracting the runner holding member 1 out of the mold by a mechanism described later, the runner is separated from the runner holding member 1 and discharged from the injection molding machine.

  Next, with reference to FIG.2 and FIG.3, the runner discharge mechanism of the injection molding machine in this embodiment is demonstrated. FIG. 2 is a diagram showing the configuration of the runner discharge mechanism and its peripheral part in the present embodiment, and FIG. 3 is a diagram showing the detailed configuration of the drive block.

  2 and 3, 1 is a runner holding member, 2 is a fixed side template, 3 is a molded product, 4 is a runner, 5 is a separation block, 6 is an intermediate plate, 7 is a movable platen, 8 is a runner frame, 9 Is a fixed platen.

  Further, 10 is a stepping motor (drive unit), 11 is a shaft, 12 and 13 are pulleys, 14 is a shoulder bolt, and 15 is a timing belt.

  Reference numerals 16 and 17 denote drive blocks, 18 denotes a shaft, 19 denotes a bush, 20 denotes a sensor light-shielding blade, 21 denotes a sensor mounting bracket, 22 denotes a first sensor, 23 denotes an E-ring, 24 denotes a fixed block, and 25 denotes a ball plunger. It is. Reference numeral 26 denotes a nozzle, 27 denotes a shoulder bolt, and 28 denotes a collar.

  A runner frame 8 that is a base of a drive mechanism of the runner holding member 1 is attached to a fixed platen 9 with screws. The runner frame 8 is provided with a long hole for passing the shaft 11 of the stepping motor 10.

  A pulley 12 is attached to the shaft 11, and a pulley 13 is also attached to the runner frame 8 with a shoulder bolt 14. A timing belt 15 is stretched between these two pulleys.

  Further, the timing belt 15 is sandwiched between the drive block 16 and the drive block 17 that are provided with grooves that match the teeth of the timing belt 15.

  In such a configuration, when the stepping motor 10 is driven, the timing belt 15 stretched on the pulleys 12 and 13 is rotated by the power transmitted to the pulley 12 via the shaft 11, and accordingly, the teeth of the timing belt 15 are rotated. The drive block 17 engaged with the mountain is driven straight.

  The drive block 17 is provided with a through hole in the direction of movement of the drive block 17 in order to restrict the movement of the drive blocks 16, 17, and a shaft 18 is passed therethrough. Further, a bush 19 is inserted into the through hole of the drive block 17 so that the drive block 17 is driven smoothly.

  By attaching the runner holding member 1 to the drive block 17, the runner holding member 1 moves linearly (in / out movement) together with the drive blocks 16 and 17. At that time, the linear motion of the runner holding member 1 is guided by the separation block 5 attached to the runner frame 8.

  With such a mechanism, the rotational motion of the stepping motor 10 can be converted into the linear motion of the runner holding member 1. The drive mechanism in this embodiment is constituted by this series of members.

  Next, the runner discharge operation in this embodiment will be described. 4A, 4B, 5A, and 5B are diagrams for explaining the runner discharging operation. FIGS. 4A and 4B show a state immediately before the runner is separated, and FIGS. 5A and 5B show just after the runner is separated. It is the figure which showed the state of.

  The rear end of the runner holding member 1 is attached to the drive block 17 with play with a collar 28 sandwiched between shoulder bolts 27.

  There is also play between the separation block 5 and the runner holding member 1, and the tip of the runner holding member 1 is normally inclined.

  Further, the drive blocks 16, 17 have a certain amount of gap A with the runner frame 8 and are stopped (the origin position at the start of molding).

  A groove having a shape corresponding to the tip portion of the runner holding member 1 is carved in the fixed side template 2, and the tip of the runner holding member 1 becomes a part of the fixed side template 2 at the time of clamping. It is inserted. Further, a U-shaped notch for forming a part of the runner 4 is provided at the tip of the runner holding member 1, and this tip is inserted near the lower portion of the nozzle 26 during mold clamping. The fixed platen 9 is fixed between the lower surface of the fixed platen 9 and the fixed-side template 2. By performing injection molding in this state, the molded product 3 is formed in the mold cavity by the injected molten resin, and a part of the runner 4 is formed by the notch portion of the runner holding member 1. 4 is fixed and held in the notch of the runner holding member 1.

  When the mold opening is completed (after the molding operation) and the mold opening is completed, the runner holding member 1 is placed in substantially the same plane as the discharge direction as a characteristic operation of the present embodiment at the start of the discharge operation of the runner 4. , Move in a direction different from the discharge direction. Thereby, the runner 4 is separated from the nozzle 26 by the shearing force.

  In this embodiment, the runner 4 is cut off from the nozzle 26 and separated in the direction opposite to the discharge direction, that is, until the drive block 17 hits the runner frame 8 in the left direction in FIG. 4A. .

  Therefore, the distance that the runner holding member 1 moves forward, that is, the distance A between the drive block 17 to which the runner holding member 1 is attached and the runner frame 8 is a distance that allows the runner 4 to be cut off from the nozzle 26 and separated. It has become. In the present embodiment, the diameter is 2 mm, but this is set to be larger than that because the diameter of the molten resin injection port of the nozzle 26 is φ1.2 mm to φ1.8 mm.

  Here, in this embodiment, as described above, the ball plunger 25 provided in the fixed block 24 acts simultaneously with the mold opening, and a force for pushing down the runner holding member 1 is also applied. As described above, the runner 4 may not be sufficiently separated from the nozzle 26 by the urging force of the ball plunger 25 alone. However, providing the ball plunger 25 closer to the nozzle 26 in order to increase the urging force of the ball plunger 25 is not preferable because the nozzle 26 is maintained at a high temperature for melting the resin material. . In addition, when the ball plunger 25 is brought close to the nozzle 26, the configuration of the fixed platen 9 becomes complicated and the cost increases.

  Moreover, the front-end | tip part of the runner holding member 1 is a U-shaped notch shape as mentioned above. Therefore, when the runner 4 is not separated from the nozzle 26 by the discharge operation only by moving the runner holding member 1 only in the discharge direction as the direction of extracting it from the mold, the runner 4 adheres to the nozzle 26 and runs. As the holding member 1 is driven, the runner holding member 1 may come off. In this case, when the next injection operation is performed while the runner 4 is fixed to the nozzle 26, the molding operation becomes an error and stops.

  In comparison with this, in the present embodiment, the runner 4 can be more reliably separated with a simple configuration in which the runner holding member 1 is simply moved in a direction different from the discharge direction. As a result, the runner is pushed in a direction that does not come out of the U-shaped notch of the runner holding member 1, so that shearing is ensured. In particular, if the runner holding member 1 is moved in the direction opposite to the discharge direction as in the present embodiment, the runner holding member 1 can be moved forward and backward without specially providing a drive mechanism for moving in another direction. Since shearing can be performed using driving, it is more preferable.

  Then, after the runner holding member 1 is advanced, the drive block 17 is moved backward in the right direction in FIG. 4A, and the runner holding member 1 is moved out of the fixed side template 2 while holding the runner 4. At that time, the runner 4 is separated from the runner holding member 1 and discharged by hitting only the runner 4 against the separation block 5 by using the operation of extracting the runner holding member 1 from the mold.

  In this embodiment, the runner holding member 1 is moved forward to cut and separate the runner 4, but the runner 4 comes off from the U-shaped notch formed at the tip of the runner holding member 1. You may drive in the direction which is not, for example, left-right direction. Further, the tip shape of the runner holding member 1 is not limited to the present embodiment formed in a U shape. For example, the tip shape formed in a U shape is provided with a claw that is fixed at one end and can be opened and closed to form a 0 shape. You may do it.

  Here, as the origin position of the runner holding member 1 at the start of molding, the sensor mounting bracket 21 is attached to the runner frame 8 for the control of the amount of the runner holding member 1 inserted into the fixed side template 2 with respect to the driving direction. This is performed by detecting the sensor light-shielding blade 20 attached to the drive block 17 by the first sensor 22 attached via the sensor.

  The amount of insertion of the runner holding member 1 is set as follows. That is, the drive blocks 16 and 17 are abutted against the runner frame 8 by advancing the runner holding member 1 in the mold direction by driving the stepping motor 10. After that, the number of pulses corresponding to the amount of the set gap A is sent to the stepping motor 10 in the discharge direction and stopped. In this state, the first sensor 22 is turned on to output an origin signal.

  Further, in order to prepare the runner holding member 1 for the next molding operation, when the positioning is performed by returning the runner discharge member from the runner discharge position to the origin position, the runner holding member 1 is advanced from the origin position and overrun is detected. In addition, the second sensor 30 (detection means) attached to the sensor attachment bracket 29 is also attached at a position where it is shielded by the sensor light shielding blade 20. When the runner holding member 1 cannot stop at the normal position and stops in a state where the runner holding member 1 has overrun the allowable value in the forward direction, the second sensor 30 cannot be shielded by the sensor light shielding blade 20 as shown in FIG. . As a result, the control unit that controls the operation of the injection molding machine stops the molding operation with an alarm and does not allow the subsequent operation. Similarly, when an overrun is detected at the stop position in the discharge direction, the molding operation is stopped.

  In addition, as the movement amount during the runner discharge operation, the movement amount by which the runner holding member 1 moves backward out of the fixed-side template 2 is determined by the software setting of the molding machine. If the drive blocks 16 and 17 are overrun due to the stepping motor 10 being out of step or the like, an E-ring 23 is attached to the shaft 18 so as not to collide with the pulley 13.

  Furthermore, if the operation | movement which cuts and isolate | separates the runner 4 from the nozzle 26 can be cut-separated by one operation | movement, the runner holding member 1 will be retracted as usual and the runner 4 will be discharged | emitted. However, when the cutting and separation cannot be performed, the runner holding member 1 is advanced again to perform the cutting and separation operation.

  Whether or not the runner 4 is cut and separated from the nozzle 26 is determined by the third sensor 41 attached to the runner frame 8 via a sensor mounting bracket.

  The third sensor 41 is a reflection type photoelectric sensor. Before the operation of separating the runner 4 from the nozzle 26, the light hits the drive block 17, and the operation of separating the runner 4 from the nozzle 26 is performed. As the light travels forward, it is mounted such that the light does not strike or the light reflection area decreases and the amount of reflected light changes. It is determined whether or not the runner holding member 1 has moved more than the amount by which the runner 4 can be separated, based on the difference between the sensor reflected light amount before runner separation and the reflected light amount during the runner separation operation.

  The method for determining the separation of the runner 4 is not limited to the method of the present embodiment, and an encoder may be attached to the stepping motor 10 that is the driving means of the runner holding member 1 and the determination may be made based on the position information. Further, the position of the movable part such as the runner 4 or the runner holding member 1 may be detected by another sensor or the like.

  Needless to say, the present invention is not limited to the above-described embodiment, and can be applied to other similar techniques as needed without departing from the spirit of the present invention.

It is a figure which shows the whole structure of the injection molding machine provided with the runner discharge mechanism concerning one Embodiment of this invention. It is a figure which shows the structure of the runner discharge mechanism and peripheral part of an injection molding machine provided with the runner discharge mechanism in one Embodiment of this invention. It is a figure which shows the detailed structure of the drive block in one Embodiment of this invention. It is a figure explaining the operation | movement which separates the runner in one Embodiment of this invention from a nozzle, and is the figure which showed the state just before isolate | separating a runner. It is a figure explaining the operation | movement which separates the runner in one Embodiment of this invention from a nozzle, and is the figure which expanded the nozzle / runner part just before isolate | separating a runner. It is a figure explaining the operation | movement which separates the runner in one Embodiment of this invention from a nozzle, and is a figure which shows the state immediately after isolate | separating a runner. It is a figure explaining the operation | movement which separates the runner in one Embodiment of this invention from a nozzle, and is the figure which expanded the nozzle / runner part immediately after isolate | separating a runner. It is a figure explaining the positioning method of the runner holding member in one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Runner holding member 2 Fixed side template 3 Molded product 4 Runner 5 Separation block 6 Intermediate plate 7 Movable platen 8 Runner frame 9 Fixed platen 10 Stepping motor 11 Shaft 14 Shoulder bolt 15 Timing belt 20 Sensor light shielding blade 21 Sensor mounting bracket 22 First 1 sensor 23 E-ring 24 fixed block 25 ball plunger 26 nozzle 27 shoulder bolt 29 sensor mounting bracket 30 second sensor 35 movable side plate 41 third sensor

Claims (5)

A nozzle for injecting molten resin into the mold,
A runner holding member for holding a runner formed at the time of injection molding;
Drive means for allowing the runner holding member to enter and exit the mold,
After the molding operation of the molded product, the runner holding member is moved in a direction different from the discharge direction in substantially the same plane as the discharge direction of the runner and then moved in the discharge direction. And injection molding machine.   It further comprises detection means for detecting whether or not the runner is separated from the nozzle by movement of the runner holding member in a direction different from the discharge direction, and the runner is separated from the nozzle by the detection means. 2. The injection molding machine according to claim 1, wherein the runner holding member is repeatedly moved in a direction different from the discharging direction until it is detected.   The injection molding machine according to claim 1 or 2, wherein an amount of movement of the runner holding member in a direction different from the discharging direction is set larger than a diameter of an injection port of the nozzle.   The injection molding machine according to any one of claims 1 to 3, wherein the direction different from the discharging direction is a direction opposite to the discharging direction.   Control further comprising detecting means for detecting the stop position of the runner holding member, and when the detecting means detects that the runner holding member is misaligned, control is not allowed to allow subsequent operations. The injection molding machine according to any one of claims 1 to 4, further comprising means.

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