Abnormal Diagnosis Method for Shut-off Nozzle, Injection Device, and Injection Molding Machine

Abstract

To provide an abnormality inspection method of a shutoff nozzle capable of determining whether replacing or not.SOLUTION: The present disclosure has an injection molding device (3) provided with a shut-off nozzle (5) composed of a nozzle portion (25) and a needle valve (26) inserted into a needle hole (36) formed obliquely with respect to an axial direction reaching an inner injection passage (34) from the outer peripheral surface as a target. The needle valve (26) is advanced to close an injection channel (34) and in this condition a screw (20) is driven to apply pressure to the injection material. The presence or absence of injection material leakage (43, 44) from the needle hole (36) or from the injection port (41) at the tip of the nozzle portion is detected.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a needle valve wear diagnosis method for diagnosing abnormalities in a shut-off nozzle, an injection device provided with a shut-off nozzle, and an injection molding machine provided with a shut-off nozzle.

Background Art

[0002] The shut-off nozzle provided in the injection device of an injection molding machine can open and close the flow path through which the injection material of the injection nozzle flows to prevent so-called drooling. There are various types of shut-off nozzles, and the type targeted by the present invention is, for example, the type described in Patent Document 1. That is, the shut-off nozzle includes a nozzle portion and a needle valve provided obliquely with respect to this nozzle portion. In this type of shut-off nozzle, an oblique hole, that is, a needle hole, reaching from the outer peripheral surface of the nozzle portion to the injection flow path inside the nozzle portion is formed. A needle valve is inserted into this needle hole so as to be able to advance and retreat. When the needle valve is advanced, the injection flow path is closed, and when it is retracted, the injection flow path is opened.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a slight gap between the needle hole and the needle valve, and the needle valve can move forward and backward smoothly. In some cases, a small amount of injection material may leak through this gap. After a long period of operation, the leaked injection material may come into contact with the heater installed in the shut-off nozzle, generating smoke. In such cases, the shut-off nozzle must be cleaned. However, if the gap has widened due to wear of the needle hole or needle valve during long-term operation, injection material leakage will occur again soon even after cleaning, so the shut-off nozzle needs to be replaced. Injection material may also leak from the tip of the nozzle part due to abnormal sealing by the needle valve in the shut-off nozzle. In such cases as well, cleaning etc. is necessary, but if wear has progressed, the shut-off nozzle also needs to be replaced.

[0005] Conventionally, there has been a problem that it is impossible to determine whether the shut-off nozzle should be replaced.

[0006] In the present disclosure, there is provided an abnormality diagnosis method for a shut-off nozzle capable of determining whether the shut-off nozzle should be cleaned or replaced.

[0007] Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.

Means for Solving the Problems

[0008] The present disclosure targets an injection device including a shut-off nozzle including a nozzle part and a needle valve inserted into the needle hole on its outer peripheral surface. The needle valve is advanced to close the injection flow path, and in this state, the screw is driven to apply pressure to the injection material, and the presence or absence of injection material leakage from the needle hole or the injection port at the tip of the nozzle part is detected. It is opened obliquely with respect to the axial direction and reaches the internal injection flow path

Effects of the Invention

Effects of the Invention

[0009] The present disclosure can determine whether the shut-off nozzle should be cleaned or replaced.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] Hereinafter, specific embodiments will be described in detail with reference to the drawings. However, it is not limited to the following embodiments. For clarity, the following description and drawings are appropriately simplified. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations are omitted as necessary. Also, there are parts where hatching is omitted so that the drawings do not become complicated.

[0012] This embodiment will be described. <Injection Molding Machine> As shown in FIG. 1, the injection molding machine 1 according to this embodiment includes a toggle type mold clamping device 2 and an injection device 3. The injection device 3 according to this embodiment is provided with a shut-off nozzle 5, and a camera 6 is provided in the vicinity of the shut-off nozzle 5. The injection molding machine 1 is provided with a control device 4, and the mold clamping device 2, the injection device 3, the shut-off nozzle 5, the camera 6, etc. are connected to the control device 4 and are controlled by the control device 4.

[0013] <Mold Clamping Device> The clamping device 2 includes a fixed platen 7 fixed to the bed B, a movable platen 8 slidably provided on the bed B, and a clamping housing 9. The fixed platen 7 and the clamping housing 9 are connected by a plurality of tie bars 11, 11, …, and the movable platen 8 is slidable between the fixed platen 7 and the clamping housing 9. A clamping mechanism, that is, a toggle mechanism 13 in this embodiment, is provided between the clamping housing 9 and the movable platen 8. Fixed-side molds 15 and movable-side molds 16 are provided on the fixed platen 7 and the movable platen 8, respectively. Therefore, when the toggle mechanism 13 is driven, the molds 15, 16 are opened and closed.

[0014] <Injection device> The injection device 3 includes a heating cylinder 19, a screw 20 provided in the heating cylinder 19, and a screw driving device 22. The heating cylinder 19 is supported by the screw driving device 22, and the screw 20 is driven in the rotational direction and the axial direction by the screw driving device 22. The heating cylinder 19 is provided with a hopper 23 and a shut-off nozzle 5 according to this embodiment described below. As shown in FIG. 2, a backflow prevention ring 24 is provided at the tip of the screw 20 of the injection device 3.

[0015] In such an injection device 3, the heating cylinder 19 is heated according to a command from the control device 4, the injection material is supplied from the hopper 23, and the screw 20 is rotated. Then, the injection material melts, flows through the backflow prevention ring 24, and is sent to the tip of the screw 20. That is, it is metered. When the injection material is metered, the screw driving device 22 is controlled according to a command from the control device 4 to drive the screw 20 in the axial direction. Then, the backflow of the injection material is prevented by the backflow prevention ring 24, and the injection material is pushed forward as the screw 20 advances. That is, the injection material is injected into the molds 15, 16.

[0016] <Shut-off nozzle according to this embodiment> As shown in Fig. 2, the shut-off nozzle 5 according to this embodiment includes a nozzle portion 25, a needle valve 26, a needle valve driving means 28 for driving the needle valve 26, and a support structure 30 for supporting the needle valve driving means 28. The nozzle portion 25 is provided with respect to the heating cylinder 19 via an adapter 32.

[0017] In the nozzle portion 25, a flow path through which the injection material flows, that is, an injection flow path 34, is formed inside. The injection flow path 34 is formed on the axial center of the nozzle portion 25. In this specification, the axial direction means the direction of the axis of the nozzle portion 25. That is, the injection flow path 34 is formed axially inside the nozzle portion 25. And the injection flow path 34 opens at the tip of the nozzle portion 25 and becomes an injection port 41 from which the injection material is injected. In such a nozzle portion 25, a hole reaching the injection flow path 34 from its outer peripheral surface, that is, a needle hole 36, is also formed. The needle hole 36 is opened obliquely with respect to the axial direction. The needle valve 26 is inserted into the needle hole 36 so as to be able to advance and retreat.

[0018] In this embodiment, the needle valve 26 is formed of a large-diameter shaft portion 38 having a large shaft diameter, a small-diameter shaft portion 39 provided at the tip of the large-diameter shaft portion 38 and having a small shaft diameter, and a hemispherical head portion 40 formed at the tip of the small-diameter shaft portion 39. A part of the small-diameter shaft portion 39 is slidably inserted into the needle hole 36 with the head portion 40 at the front. The needle valve driving means 28 for driving the needle valve 26 is composed of a piston cylinder unit and is supported by the support structure 30. When the needle valve driving means 28 is driven according to a command from the control device 4 (see Fig. 1), the needle valve 26 moves forward and backward, and the head portion 40 closes and opens the injection flow path 34. When the injection flow path 34 is closed, leakage of the injection material from the injection port 41 is prevented.

[0019] As described above, the camera 6 is provided in the vicinity of the shut-off nozzle 5 configured as described above. More specifically, the camera 6 is configured to photograph the vicinity of the outlet of the needle hole 36 and the vicinity of the injection port 41 of the nozzle portion 25.

[0020] When the needle valve 26 is advanced, injection material leakage from the injection port 41 should be prevented as described above. However, if residues of the injection material accumulate on the head 40 of the needle valve 26, or if wear of the head 40 or the injection flow path 34 of the nozzle portion 25 progresses, the sealing effect by the needle valve 26 decreases. As will be described later, in the abnormality detection method for detecting an abnormality of the shut-off nozzle 5, pressure is applied to the injection material with the injection flow path 34 closed by the head 40 of the needle valve 26. At this time, the camera 6 is configured to detect whether there is injection material leakage 43 from the injection port 41 as shown in FIG. 3.

[0021] The camera 6 is also configured to detect injection material leakage 44 from the needle hole 36. The inner diameter of the needle hole 36 is slightly larger than the shaft diameter of the small-diameter shaft portion 39 of the needle valve 26, and the needle valve 26 can be driven smoothly. In a normal state, since the gap between the needle hole 36 and the small-diameter shaft portion 39 is small, the injection material in the injection flow path 34 hardly leaks through this gap. However, after a long period of operation, the gap expands due to wear of the needle hole 36 and the small-diameter shaft portion 39 of the needle valve 26, resulting in injection material leakage. As will be described later, in the abnormality detection method for detecting an abnormality of the shut-off nozzle 5, pressure is applied to the injection material with the injection flow path 34 closed by the head 40 of the needle valve 26. At this time, the camera 6 is configured to detect the presence or absence of injection material leakage 44 from the needle hole 36.

[0022] The camera 6 detects injection material leakage 43 from the injection port 41 and injection material leakage 44 from the needle hole 36, and specifically detects them as follows. That is, the control device 4 (FIG. 1) inspects the image captured by the camera 6. Then, it compares the image when there is no injection material leakage 43, 44 (i.e., a normal image) with the image captured when the abnormality diagnosis method described below is being performed, and searches for a portion where the luminance has changed. If there is a changing portion and its size is equal to or greater than a specified size, it is determined that injection material leakage 43, 44 has occurred.

[0023] <Abnormal Diagnosis Method for Shut-off Nozzle According to this Embodiment> The abnormal diagnosis method for the shut-off nozzle 5 according to this embodiment is composed of the first to third phases. The first phase is to inspect whether the seal at the head 40 of the needle valve 26 is normal or abnormal, and to inspect whether the wear of the needle hole 36 and the small-diameter shaft portion 39 of the needle valve 26 is progressing. Then, the second phase is implemented when the wear of the needle hole 36 and the small-diameter shaft portion 39 of the needle valve 26 is progressing, and it is configured to inspect whether the wear has reached the specified wear amount.

[0024] The third phase is an independent phase, and it is configured to detect as many detectable abnormalities as possible to identify the problematic parts. That is, not only to inspect the presence or absence of seal abnormalities and wear of the shut-off nozzle 5, but also to inspect the wear of the backflow prevention ring 24. This enables the disassembly work of the shut-off nozzle 5 to be completed in one operation.

[0025] <The First Phase> Implement the first phase of the abnormal diagnosis method for the shut-off nozzle 5 according to this embodiment. As shown in FIG. 4, the needle valve 26 is advanced (step S01). That is, the control device 4 (see FIG. 1) drives the needle valve driving means 28 (see FIG. 2) to advance the needle valve 26. Then, the injection flow path 34 of the nozzle portion 25 is closed by the head 40.

[0026] The control device 4 performs the first pressure application step (step S02). The first pressure is set in the control device 4 and corresponds to the pressure during injection. The screw drive device 22 is driven so as to reach this first pressure, and pressure is applied to the injection material via the screw 20. In this step, the control device 4 may simply perform the injection step. In the injection step, the control device 4 controls the speed of the screw 20. However, if the speed does not reach the target speed, the control device 4 controls the screw 20 so as not to exceed a specified pressure limiter. This pressure limiter substantially corresponds to the pressure during injection and is the first pressure.

[0027] When performing the step S02, the presence or absence of injection material leakage 43, 44 (see FIG. 3) is detected. First, the control device 4 obtains an image by the camera 6 and detects the presence or absence of injection material leakage 43 at the injection port 41 (step S03). If there is injection material leakage 43 from the injection port 41, it is determined that there is a seal abnormality (step S04). That is, it is determined that the seal at the head 40 of the needle valve 26 is abnormal. The control device 4 issues an alarm that the shut-off nozzle 5 needs to be cleaned or replaced. If there is no injection material leakage 43 at the injection port 41, the control device 4 proceeds to step S05.

[0028] In step S05, the control device 4 inspects the presence or absence of injection material leakage 44 in the needle hole 36. If no injection material leakage 44 has occurred, the control device 4 determines that there is no wear in the needle valve 26 and the needle hole 36 (step S06). Here, the first phase is completed, and the control device 4 outputs a message that there is no abnormality in the shut-off nozzle 5. On the other hand, in step S05, if the control device 4 detects injection material leakage 44, it is determined that wear has occurred in the needle valve 26 and the needle hole 36 (step S07). The control device 4 warns that wear has occurred. Here, the first phase is completed. The control device 4 may end the process here. However, in the present embodiment, the second phase is continuously performed.

[0029] <Second Phase> <When performing the second phase, it is assumed that the needle valve 26 (see FIG. 2) is advanced and the injection flow path 34 is closed by the head 40. Since the injection flow path 34 has already been closed in step S01 in the first phase, step S08 is performed as it is.>

[0030] <In step S08, a second pressure application process is performed. The control device 4 controls the screw 20 by the screw drive device 22 (see FIG. 1) to apply a second pressure set in the control device 4 to the injection material. The second pressure is smaller than the first pressure and corresponds to the back pressure during metering. The control device 4 may simply perform a metering process. This is because the injection material is metered by the metering process and the second pressure is applied to the injection material.>

[0031] <The control device 4 obtains an image by the camera 6 and determines the presence or absence of injection material leakage 44 from the needle hole 36 (see FIG. 3) (step S09). However, as already determined in step S07, injection material leakage 44 has occurred from the needle hole 36. In this step S09, it is to check whether the amount of injection material leakage 44 has increased in the process of step S08. If the amount of injection material leakage 44 has not increased, it is determined (step S10) that the wear of the needle valve 26 and the needle hole 36 has not reached the specified wear amount. For example, it is determined that the gap between the needle valve 26 and the needle hole 36 is less than 0.03 mm. The shut-off nozzle 5 does not necessarily need to be replaced and can continue to be used.>

[0032] <On the other hand, if it is detected in step S09 that the amount of injection material leakage 44 has increased, the control device 4 proceeds to step S11. That is, it is determined (step S11) that the wear of the needle valve 26 and the needle hole 36 has reached the specified wear amount. For example, it is determined that the gap between the needle valve 26 and the needle hole 36 has become 0.03 mm or more. The control device 4 issues an alarm prompting the replacement of the shut-off nozzle 5. The second phase ends.>

[0033] <Third Phase> The third phase in the method for diagnosing abnormalities of the shut-off nozzle 5 according to the present embodiment will be described with reference to FIG. 5. First, the control device 4 (see FIG. 1) drives the needle valve 26 (see FIG. 2) in step S21 to close the injection flow path 34 with the head 40. Next, the control device 4 drives the screw 20 by the screw drive device (22) to apply a first pressure to the injection material (step S22). At this time, the presence or absence of injection material leakage 43 from the injection port (41) (see FIG. 3) is checked (step S23). If there is injection material leakage 43, it is determined in step S23 that there is a seal abnormality. The control device 4 issues an alarm indicating that the shut-off nozzle 5 needs to be cleaned or replaced, and ends the process.

[0034] On the other hand, if there is no injection material leakage 43, the presence or absence of injection material leakage 44 from the needle hole 36 (see FIG. 3) is checked (step S25). If there is leakage, the control device 4 determines in step S26 that there is wear in the needle valve 26 and the needle hole 36, and warns that wear has occurred. The process ends. However, if the injection material leakage 44 from the needle hole 36 is not detected in step S25, the control device 4 performs step S27 and determines that there is no abnormality in the shut-off nozzle 5. The control device 4 proceeds with the process.

[0035] The control device 4 performs a third pressure application step (step S28). That is, the screw 20 is driven so that the injection material reaches the third pressure set in the control device 4. The third pressure is a pressure lower than the first pressure. When performing this step S28 in a vertical injection molding machine, the control of the servo motor that drives the screw 20 may be completely stopped to make it so-called servo-free. In this way, pressure is applied to the injection material by the self-weight of the screw 20. The third pressure is a pressure of approximately the same magnitude as the pressure applied at this time.

[0036] When a third pressure is applied to the injection material in this way, it is checked whether the screw 20 advances (step S29). If the advancement of the screw 20 is detected, it is determined in step S30 that wear has occurred in the backflow prevention ring 24 (see FIG. 2). The control device 4 (see FIG. 1) outputs an alarm prompting replacement of the backflow prevention ring 24. On the other hand, if the advancement of the screw 20 is not detected, it is determined in step S31 that the backflow prevention ring 24 is normal. The control device 4 ends the process.

[0037] <Modifications of the present embodiment> The present embodiment can be variously modified. For example, there is also a method that does not use the camera 6 to check for injection material leaks 43, 44 (see FIG. 3). Instead of the camera 6, an operator who operates the control device 4 (see FIG. 1) of the injection molding machine 1 may visually check for the presence or absence of injection material leaks 43, 44.

[0038] The first to third phases described in the abnormal diagnosis method of the shut-off nozzle according to the present embodiment can also be modified. For example, in the first phase, the order of step S03 and step S05 can be switched. Similarly, in the third phase, the order of step S23 and step S25 can be switched. If it is clear that there is no abnormality in the shut-off nozzle 5 (see FIG. 2), after step S21 is performed in the third phase, the process may proceed to step S28. Furthermore, although the second phase has been described as being continuously performed after the first phase, it can also be performed alone. When the second phase is performed alone, the control device 4 advances the needle valve 26 to close the injection flow path 34 with the head 40, and then performs step S08.

[0039] As described above, the invention made by the present inventor has been specifically described based on the embodiments. However, it goes without saying that the present invention is not limited to the embodiments already described, and various changes can be made without departing from the gist thereof. The plurality of examples described above can also be implemented in appropriate combinations.

Explanation of reference numerals

[0040] 1 Injection molding machine 2 Clamping device 3 Injection device 4 Control device 5 Shut-off nozzle 6 Camera 7 Fixed platen 8 Movable platen 9 Clamping housing 11 Tie bar 13 Toggle mechanism 15 Fixed-side mold 16 Movable-side mold 19 Heating cylinder 20 Screw 22 Screw drive device 23 Hopper 24 Backflow prevention ring 25 Nozzle part 26 Needle valve 28 Needle valve drive means 30 Support structure 32 Adapter 34 Injection flow path 36 Needle hole 38 Large-diameter shaft part 39 Small-diameter shaft part 40 Head 41 Injection port 43 Leakage of injection material 44 Leakage of injection material B Bed

Claims

1. A heating cylinder, a screw placed in the heating cylinder, and a shut-off nozzle provided on the heating cylinder, comprising: the shut-off nozzle includes a nozzle portion in which an injection flow path for flowing an injection material is formed in the axial direction, and a needle valve, in an injection device in which the needle valve is inserted through a gap with respect to a needle hole that is obliquely opened from the outer peripheral surface of the nozzle portion in the axial direction and reaches the injection flow path, and moves forward and backward to open and close the injection flow path, an injection flow path closing step of advancing the needle valve to close the injection flow path; a wear inspection step of driving the screw to apply pressure to the injection material in a state where the injection flow path is closed, and detecting the presence or absence of leakage of the injection material from the needle hole or from an injection port at the tip of the nozzle portion. A method for diagnosing an abnormality of a shut-off nozzle.

2. The shut-off nozzle includes a camera, and the detection of the presence or absence of leakage of the injection material in the wear inspection step is determined by an image of the shut-off nozzle obtained by the camera. The method for diagnosing an abnormality of a shut-off nozzle according to claim 1.

3. The detection of leakage of the injection material from the image is determined by a change in the luminance of the image. The method for diagnosing an abnormality of a shut-off nozzle according to claim 2.

4. The wear inspection step includes a first pressure application step of driving the screw to apply a first pressure corresponding to an injection pressure to the injection material. The method for diagnosing an abnormality of a shut-off nozzle according to any one of claims 1 to 3.

5. The wear inspection step includes a third pressure application step of applying, by the screw, a third pressure smaller than the first pressure to the injection material after the first pressure application step and maintaining it for a specified time. The method for diagnosing an abnormality of a shut-off nozzle according to claim 4.

6. The wear inspection step includes a second pressure application step of applying, by the screw, a second pressure corresponding to a back pressure during metering to the injection material. The method for diagnosing an abnormality of a shut-off nozzle according to any one of claims 1 to 5.

7. In the wear inspection step, when leakage of the injection material from the needle hole is detected, it is determined that wear has occurred between the needle valve and the needle hole. The method for diagnosing an abnormality of a shut-off nozzle according to any one of claims 1 to 6.

8. The abnormality diagnosis method of the shut-off nozzle according to any one of claims 1 to 6, wherein in the wear inspection step, when leakage of the injection material from the injection port is detected, it is determined that there is a seal abnormality at the tip of the needle valve.

9. The abnormality diagnosis method of the shut-off nozzle according to any one of claims 1 to 6, wherein in the wear inspection step, when the screw is advancing and no leakage of the injection material is detected from the needle hole or the injection port, it is determined that wear has occurred in the backflow prevention ring provided on the screw.

10. The wear inspection step includes first and second phases, and first and second inspections carried out in each of the first and second phases. The first phase is a phase in which a first pressure application step of applying a first pressure corresponding to the injection pressure to the injection material is carried out. The second phase is a phase in which a second pressure application step of applying a second pressure corresponding to the back pressure during metering to the injection material is carried out. The first inspection is an inspection for detecting leakage of the injection material from the needle hole. The second inspection is an inspection for detecting leakage of the injection material from the injection port. When the first phase is carried out and leakage of the injection material is detected by the first inspection, it is determined that wear has occurred in the needle valve and the needle hole. Next, when the second phase is carried out and leakage of the injection material is detected by the first inspection, it is determined that the amount of wear exceeds the specified wear amount, and when no leakage is detected, it is determined that the amount is equal to or less than the specified wear amount. The abnormality diagnosis method of the shut-off nozzle according to any one of claims 1 to 3, wherein when the first phase is carried out and leakage of the injection material is detected by the second inspection, it is determined that there is a seal abnormality at the tip of the needle valve.

11. The wear inspection step includes a third phase, and first and second inspections carried out in each of the third phase. The first inspection is an inspection for detecting leakage of the injection material from the needle hole. The second inspection is an inspection for detecting leakage of the injection material from the injection port. The third phase includes a first pressure application step of applying a first pressure corresponding to the injection pressure to the injection material, and a third pressure application step of applying a third pressure smaller than the first pressure to the injection material. In the first pressure application step, when the first and second inspections are carried out and no injection material leakage is detected, and when the forward movement of the screw is detected in the third pressure application step, it is determined that wear has occurred in the backflow prevention ring provided on the screw. The method for diagnosing an abnormality of a shut-off nozzle according to any one of claims 1 to 3.

12. A control device, A heating cylinder, A screw placed in the heating cylinder, A shut-off nozzle provided in the heating cylinder, comprising: The shut-off nozzle includes a nozzle portion in which an injection flow path for flowing an injection material is formed in the axial direction, A needle valve, The needle valve is inserted through a gap with respect to a needle hole that is obliquely opened in the axial direction from the outer peripheral surface of the nozzle portion and reaches the injection flow path, and advances and retreats to open and close the injection flow path. The control device includes an injection flow path closing step of advancing the needle valve to close the injection flow path, An injection device that, in a state where the injection flow path is closed, drives the screw to apply pressure to the injection material and detects the presence or absence of injection material leakage from the needle hole or from the injection port at the tip of the nozzle portion.

13. The injection device includes a camera, and the detection of the presence or absence of injection material leakage in the wear inspection step is determined based on an image of the shut-off nozzle obtained by the camera. The injection device according to claim 12.

14. The detection of injection material leakage from the image is determined based on a change in the brightness of the image. The injection device according to claim 13.

15. The wear inspection step includes a first pressure application step of applying a first pressure corresponding to the injection pressure during injection to the injection material. The injection device according to any one of claims 12 to 14.

16. The wear inspection step includes a third pressure application step of applying a third pressure smaller than the first pressure to the injection material by the screw after the first pressure application step and maintaining it for a specified time. The injection device according to claim 15.

17. The wear inspection step includes a second pressure application step of applying a second pressure corresponding to the back pressure during metering to the injection material by the screw. The injection device according to any one of claims 12 to 16.

18. A control device, A mold clamping device for clamping a mold, An injection molding machine comprising an injection device for injecting an injection material. The injection device includes a heating cylinder. A screw placed in the heating cylinder. A shut-off nozzle provided in the heating cylinder. The shut-off nozzle includes a nozzle portion in which an injection flow path for flowing the injection material is formed in the axial direction. A needle valve. The needle valve is inserted through a gap with respect to a needle hole that is obliquely opened from the outer peripheral surface of the nozzle portion in the axial direction and reaches the injection flow path, and advances and retreats to open and close the injection flow path. The control device includes an injection flow path closing step of advancing the needle valve to close the injection flow path. A wear inspection step of driving the screw with the injection flow path closed to apply pressure to the injection material and detecting the presence or absence of leakage of the injection material from the needle hole or from the injection port at the tip of the nozzle portion. An injection molding machine is configured to perform the steps.

19. The injection molding machine according to claim 18, further comprising a camera, wherein the detection of the presence or absence of leakage of the injection material in the wear inspection step is determined based on an image of the shut-off nozzle obtained by the camera.

Images