Patent Application
20250010532
The present invention relates to an injection device configured to inject an injection material by causing an injection nozzle to touch a sprue of a mold, an injection molding machine including such an injection device, and a nozzle touch method.
An injection molding machine includes a mold clamping device for clamping a mold and an injection device for melting and injecting an injection material. The injection device includes a heating cylinder, a screw, a screw driving mechanism for driving the screw, and a nozzle touch device. An injection nozzle is provided at a tip end of the heating cylinder. When the nozzle touch device is driven, the entire injection device slides so that the injection nozzle can touch a sprue of the mold.
In a nozzle touch in which the injection nozzle is caused to touch the sprue of the mold, it is necessary to prevent so-called misalignment, which is misalignment between the center of the injection nozzle and the center of the sprue of the mold. Since the sprue is formed in a spherical shape, when the injection nozzle touches in a state where misalignment occurs, the injection nozzle is guided by a spherical surface and slides in a direction in which the misalignment is eliminated. According to the related art, at the time of nozzle touch, an observer is placed in the vicinity of the injection nozzle to observe the presence or absence of sliding of the injection nozzle and to check the presence or absence of misalignment. However, an observer is required, which increases the work cost.
Patent Literature 1 describes a detection method for detecting an abnormality in various nozzle touches. In the method described in the literature, a normal nozzle touch is performed in advance, and a change in touch force at this time is stored as a reference pattern. When the injection nozzle is caused to touch a sprue of a mold, a change in the touch force is measured. The measured change in touch force is compared with the reference pattern, and when the deviation exceeds an allowable range, it is determined that there is an abnormality in the nozzle touch.
In the method described in Patent Literature 1, the nozzle touch can be performed without requiring an observer and without incurring the work cost. Further, the method described in Patent Literature 1 is excellent in that not only misalignment but also various abnormalities such as insert of a foreign matter between the injection nozzle and the mold and resin leakage can be detected. However, there is a problem that it is necessary to obtain the reference pattern in advance and to prepare in advance.
In view of the above problems, the present disclosure proposes an injection device that can easily detect the presence or absence of misalignment between the center of an injection nozzle and the center of a sprue of a mold, an injection molding machine, and a nozzle touch method.
Other problems and novel features will become apparent from description of the present description and the accompanying drawings.
The present inventors have found that the above problems can be solved by adopting the following configurations. An injection device includes a heating cylinder, a screw provided in the heating cylinder, a screw driving device configured to drive the screw, and a nozzle touch device. The screw driving device includes a load cell configured to detect an injection pressure at the time of injection. In the injection device according to the present disclosure, the load cell is disposed at a position separated from an extension line of an axis of the screw. In the injection device according to the present disclosure, in a case where the injection nozzle is caused to touch a sprue of a mold by the nozzle touch device, a pressure of the load cell is monitored, and misalignment between the injection nozzle and the sprue is detected based on the pressure.
According to the present disclosure, it is possible to provide an injection device that can easily detect the presence or absence of misalignment between an injection nozzle and a sprue of a mold, an injection molding machine including the injection device, and a nozzle touch method.
Hereinafter, specific embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment. In order to clarify the description, the following description and the drawings are simplified as appropriate. In the drawings, the same elements are denoted by the same reference numerals, and repeated description thereof is omitted as necessary. In addition, hatching may be omitted to avoid complicating the drawings.
The present embodiment will be described.
An injection device according to the present embodiment includes:
An injection molding machine according to the present embodiment includes:
A nozzle touch method according to the present embodiment is a method for an injection device,
The mold clamping device 2 includes a fixed platen 7 fixed on the bed B, a mold clamping housing 8 that is slidable on the bed B, and a movable platen 10 that is also slidable on the bed B. The fixed platen 7 and the mold clamping housing 8 are coupled by a plurality of, for example, four tie bars 11, 11 . . . . The movable platen 10 is slidable between the fixed platen 7 and the mold clamping housing 8. A mold clamping mechanism 12 is provided between the mold clamping housing 8 and the movable platen 10. The mold clamping mechanism 12 may be implemented by a direct pressure type mold clamping mechanism, that is, a mold clamping cylinder. In the present embodiment, the mold clamping mechanism 12 is implemented by a toggle mechanism.
The fixed platen 7 is provided with a fixed mold 14, and the movable platen 10 is provided with a movable mold 15. The mold clamping device 2 is covered with a safety cover 17, and the fixed platen 7, the fixed mold 14, and the like are exposed. The subunit injection device 5 according to the present embodiment is connected to the exposed fixed mold 14 from a side thereof.
The injection device 3, which is a part of the injection molding machine 1, includes a heating cylinder 19, a screw 20 provided in the heating cylinder 19, and a screw driving device 22 configured to drive the screw 20. A hopper 23 is provided in the vicinity of a rear end portion of the heating cylinder 19. An injection nozzle 24 is provided at a tip end of the heating cylinder 19. A nozzle touch device 27 is provided between the screw driving device 22 and the fixed platen 7. When the nozzle touch device 27 is driven, the entire injection device 3 slides in a direction toward or away from the fixed platen 7. Accordingly, the injection nozzle 24 touches the fixed mold 14 or is separated from the fixed mold 14. The screw driving device 22 of the injection device 3 will be described later.
In the present embodiment, the injection device is preferably a subunit injection device, which is adapted to be additionally connected to an injection molding machine.
As shown in
The screw driving device 38 includes a front plate 44 to which the heating cylinder 35 is fixed, and an intermediate plate 45 provided parallel to the front plate 44. The front plate 44 and the intermediate plate 45 are connected by two ball screw mechanisms 46. More specifically, attachment holes 48, 48 are formed in the front plate 44. The ball screw mechanisms 46, 46 include respective ball screws 46a, 46a and ball nuts 46b, 46b. The ball nuts 46b, 46b are respectively provided in the attachment holes 48, 48 of the front plate 44. One of the ball nuts 46b is fixed to a load cell 50, and the other is fixed to a dummy load cell 51. The load cell 50 and the dummy load cell 51 are fixed to the front plate 44.
Through holes 53, 53 are formed in the intermediate plate 45. The ball screws 46a, 46a are rotatably supported in the through holes 53, 53 in a state where movement in an axial direction is restricted. The ball screws 46a, 46a are provided with pulleys 57, 57. A timing belt 58 is wound around the pulleys 57, 57. An injection motor 55 including a speed reducer 55a is provided on the intermediate plate 45, and rotates one ball screw 46a. Accordingly, when the injection motor 55 is driven, the ball screws 46a, 46a are synchronously rotated, and the intermediate plate 45 slides in a direction toward or away from the front plate 44.
In the intermediate plate 45, a screw support portion 60 is provided, which is rotatable and is configured to support the screw 36 at its rear end portion. Therefore, when the injection motor 55 is driven to slide the intermediate plate 45 in a direction toward the front plate 44, the screw 36 is driven in the axial direction to inject the injection material. The intermediate plate 45 includes a plasticizing motor 61 having a speed reducer 61a. Although not shown, the rotation of the speed reducer 61a is transmitted to the screw support portion 60 via a transmission mechanism, so that the screw 36 rotates. That is, the injection material is plasticized.
As described above, in the present embodiment, it is preferable that the screw driving device includes the front plate that supports the heating cylinder at an end portion and the intermediate plate that rotatably supports the screw, and the load cell is provided on the front plate.
As shown in
The nozzle touch method according to the present embodiment detects misalignment between the injection nozzle 34 and the sprue 14a of the fixed mold 14 based on the pressure detected by the load cell 50 as described below. The load cell 50 is originally used to detect the injection pressure at the time of injection, as described below. That is, the injection motor 55 is driven at the time of injection. Then, as shown in
<Nozzle Touch Method according to Present Embodiment>
The nozzle touch method according to the present embodiment will be described. The controller 32 starts monitoring the pressure detected by the load cell 50. The controller 32 drives a nozzle touch device (not shown) to drive the injection device main body 31 toward the fixed mold 14. Eventually, the injection nozzle 34 touches the sprue 14a of the fixed mold 14. If an axis of the injection nozzle 34 coincides with the center of the sprue 14a, even if a touch force acts on the front plate 44 via the injection nozzle 34 and the heating cylinder 35, the pressure is hardly detected in the load cell 50. This is because a distance between the front plate 44 and the intermediate plate 45 does not change during forward and backward movement of the injection device main body 31, so that no pressure is applied to the load cell 50.
However, if the axis of the injection nozzle 34 is deviated from the center of the sprue 14a as shown in
The reason why the occurrence of the misalignment can be detected in the load cell 50 in this way is that the occurrence of the moment 66 can be detected by the load cell 50. This is because the load cell 50 is disposed at a position separated from an extension line of the axis of the screw 36.
As shown in
As described above, when the pressure is detected in the load cell 50, the controller 32 can determine that the misalignment has occurred, and the controller 32 can also detect a direction of the misalignment based on whether the pressure is positive or negative. Further, the controller 32 can evaluate the magnitude of the misalignment based on the magnitude of the pressure.
The injection device 3 configuring the injection molding machine 1 (see
As shown in
The intermediate plate 73 and the rear plate 72 are coupled by four ball screw mechanisms 77, 77. Although only two ball screw mechanisms 77, 77 are shown in
As shown in
The rear plate 72 is provided with two injection motors 85, 85, and ball screws 77a, 77a, . . . are rotated by power transmission mechanisms 86, 86. Therefore, when the injection motors 85, 85 are driven, the intermediate plate 73 and the screw 20 are driven in the axial direction. A screw support portion 88 coupled to the screw 20 is rotatably provided on the intermediate plate 73. The intermediate plate 73 is provided with two plasticizing motors 89, 89 and the screw 20 is rotated by a power transmission mechanism 90 via the screw support portion 88.
Although the injection nozzle 24 is indicated by a dotted line in
The present embodiment can be variously modified. For example, in the present embodiment, a screw driving device may include a front plate that supports a heating cylinder at an end portion and an intermediate plate that rotatably supports a screw, and a load cell may be provided on the intermediate plate.
In both of the subunit injection devices 5 and 5′ (see
As described above, in the present embodiment, the load cells are preferably provided at two or more different positions in the screw driving device. Further, as the nozzle touch method, a method is also preferable in which the load cells are provided at two or more different positions in the screw driving device, and the pressure of the load cells at the two or more positions is monitored to detect the misalignment between the injection nozzle and the sprue.
The subunit injection device 5 according to the present embodiment described with reference to
Although the invention made by the present inventors is specifically described based on the embodiments, it is needless to say that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention. The plurality of examples described above may be appropriately combined.
According to the present disclosure, it is possible to provide an injection device that can easily detect the presence or absence of misalignment between an injection nozzle and a sprue of a mold, an injection molding machine, and a nozzle touch method.
Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.
The present application is based on Japanese Patent Application No. 2021-183864 filed on Nov. 11, 2021, and the contents thereof are incorporated herein as reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-183864 | Nov 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/041977 | 11/10/2022 | WO |
