Resin cutting device, granulator, and control method for resin cutting device

Abstract

Adjustment or grinding processing of a rotation shaft retreating force as a constituent element of a tool blade pressing force in a resin cutting device is automated. In a technical idea of controlling a tool blade pressing force for pressing a plurality of tool blades for cutting resin into pellets onto a mold provided on a resin discharge side of an extruder, after the amount of wear of the plurality of tool blades is detected, the magnitude of a rotating shaft retreating force applied to a rotating shaft is automatically controlled on the basis of the detected amount of wear of the plurality of tool blades.

Description

Technical Field

[0001] The present invention relates to a resin cutting device, a granulator and a control technology for the resin cutting device, for example, to a technology and effective technology for cutting resin with multiple tool blades while controlling the tool blade pressing force against a mold to be constant. Background Art

[0002] Japanese Patent No. 3751014 (Patent Document 1) describes a technique for controlling the pressing force of a tool edge to be constant.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 3751014 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The resin cutting device is a device that produces pellets by, for example, rotating a plurality of cutter blades in water while constantly pressing the plurality of cutter blades at a predetermined pressure against the surface of a die that discharges a linear molten resin, thereby cutting the resin.

[0008] Here, if the blade pressing force of the plurality of blades is not appropriate, there is a risk of excessive wear of the plurality of blades and poor cutting of the resin. In this case, there is a risk of shortening the life of each of the plurality of blades and reducing the quality of the pellets as a product.

[0009] In this regard, when the blade pressing force is not appropriate, the rotation axis retreat force, which is one of the forces constituting the blade pressing force, is adjusted, but this adjustment is performed manually. Therefore, the adjustment of the blade pressing force depends on the experience and skill level of the worker. Therefore, it is desirable to automate the adjustment of the blade pressing force.

[0010] Means for solving problems

[0011] A control method for a resin cutting device in one embodiment is a control method for a resin cutting device that produces pellets by cutting a resin discharged from an extruder with a plurality of tool blades. The control method for the resin cutting device includes: a process for controlling the tool blade pressing force of pressing the plurality of tool blades to a mold provided on the resin discharge side of the extruder. Furthermore, the process for controlling the tool blade pressing force includes: a wear amount detection process, which detects the wear amount of the plurality of tool blades during the operation of the resin cutting device that cuts the resin into pellets; and a rotating shaft retraction force control process, which controls the magnitude of the rotating shaft retraction force applied to the rotating shaft mounted on a tool head provided with the plurality of tool blades, according to the wear amount of the plurality of tool blades detected in the wear amount detection process.

[0012] A control method for a resin cutting device in one embodiment is a control method for a resin cutting device that produces pellets by cutting a resin discharged from an extruder with a plurality of blades, wherein the control method for the resin cutting device comprises: before performing the action of cutting the resin into pellets, grinding each of the plurality of blades. Here, the steps for implementing the grinding process include: (a) a step of making a plurality of tool blades contact with a mold arranged on the resin discharge side of the extruder according to the output from a position sensor for controlling forward and backward movement and an output from a position sensor for detecting the amount of wear, wherein the position sensor for controlling the forward and backward movement of a rotating shaft installed on a tool head equipped with a plurality of tool blades; (b) a step of obtaining a first position of the tool head according to the output from the position sensor for detecting the amount of wear after step (a); (c) a step of implementing the grinding process for a predetermined time after step (b); (d) a step of obtaining a second position of the tool head according to the output from the position sensor for detecting the amount of wear after step (c); (e) a step of calculating the difference between the first position and the second position after step (d); and (f) a step of comparing the difference with a preset setting value after step (e) to determine whether to end the grinding process.

[0013] A resin cutting device in one embodiment includes: a die disposed on the resin discharge side of an extruder; a plurality of nozzles disposed on the die; a plurality of blades for cutting the resin discharged from the plurality of nozzles into pellets; a cutter head provided with a plurality of blades; a rotating shaft mounted on the cutter head; a motor for rotating the rotating shaft; a flow path chamber constituting a flow path space connected to the cutter head; an inlet for allowing a fluid to flow into the flow path chamber; an outlet for allowing a fluid and pellets to flow out of the flow path chamber; a control unit for controlling the blade pressing force for pressing the plurality of blades to the die; a rotating shaft forward force generating unit for causing the rotating shaft to generate a rotating shaft forward force; a rotating shaft backward force generating unit for causing the rotating shaft to generate a rotating shaft backward force; a forward and backward movement control position sensor for controlling the forward and backward movement of the rotating shaft; and a wear amount detection position sensor for detecting the wear amount of the plurality of blades. The control unit controls the magnitude of the rotating shaft backward force applied to the rotating shaft according to the output from the wear amount detection position sensor.

[0014] A resin cutting device in one embodiment includes: a die disposed on the resin discharge side of an extruder; a plurality of nozzles disposed on the die; a plurality of blades for cutting the resin discharged from the plurality of nozzles into pellets; a cutter head equipped with a plurality of blades; a rotating shaft mounted on the cutter head; a motor for rotating the rotating shaft; a flow path chamber constituting a flow path space connected to the cutter head; an inlet for allowing a fluid to flow into the flow path chamber; an outlet for allowing a fluid and pellets to flow out of the flow path chamber; a control unit for controlling the blade pressing force for pressing the plurality of blades to the die; a rotating shaft forward force generating unit for causing the rotating shaft to generate a rotating shaft forward force; a rotating shaft backward force generating unit for causing the rotating shaft to generate a rotating shaft backward force; a forward and backward movement control position sensor for controlling the forward and backward movement of the rotating shaft; and a wear amount detection position sensor for detecting the wear amount of the plurality of blades. The control unit includes a grinding control unit for controlling the grinding process performed on the plurality of blades respectively before the action of cutting the resin into pellets is performed. The grinding control unit includes: a first position acquisition unit, which acquires a first position of a tool head equipped with multiple tool blades based on an output from a position sensor for detecting the amount of wear; a second position acquisition unit, which acquires a second position of the tool head after a predetermined time of performing a grinding process based on an output from the position sensor for detecting the amount of wear; a difference calculation unit, which calculates the difference between the first position and the second position; a comparison unit, which compares the difference with a preset set value; and a judgment unit, which judges whether to end the grinding process based on the comparison result of the difference and the set value.

[0015] A pelletizer in one embodiment includes: an extruder; and a resin cutting device for cutting the resin extruded from the extruder into pellets. The resin cutting device includes: a die provided on the resin discharge side of the extruder; a plurality of nozzles provided on the die; a plurality of blades for cutting the resin discharged from the plurality of nozzles into pellets; a cutter head provided with a plurality of blades; a rotating shaft mounted on the cutter head; a motor for rotating the rotating shaft; a flow path chamber constituting a flow path space connected to the cutter head; an inlet for allowing a fluid to flow into the flow path chamber; an outlet for allowing a fluid and particles to flow out of the flow path chamber; a control unit for controlling the blade pressing force for pressing the plurality of blades to the die; a rotating shaft forward force generating unit for causing the rotating shaft to generate a rotating shaft forward force; a rotating shaft backward force generating unit for causing the rotating shaft to generate a rotating shaft backward force; a forward and backward movement control position sensor for controlling the forward and backward movement of the rotating shaft; and a wear amount detection position sensor for detecting the wear amount of the plurality of blades. The control unit controls the magnitude of the rotating shaft backward force applied to the rotating shaft according to the output from the wear amount detection position sensor.

[0016] A pelletizer in one embodiment includes: an extruder; and a resin cutting device for cutting the resin extruded from the extruder into pellets. The resin cutting device includes: a die provided on the resin discharge side of the extruder; a plurality of nozzles provided on the die; a plurality of cutter blades for cutting the resin discharged from the plurality of nozzles into pellets; a cutter head provided with a plurality of cutter blades; a rotating shaft mounted on the cutter head; a motor for rotating the rotating shaft; a flow path chamber constituting a flow path space connected to the cutter head; an inlet for allowing a fluid to flow into the flow path chamber; an outlet for allowing a fluid and pellets to flow out of the flow path chamber; a control unit for controlling the cutting force of the cutter blades for pressing the plurality of cutter blades to the die; a rotating shaft forward force generating unit for causing the rotating shaft to generate a rotating shaft forward force; a rotating shaft backward force generating unit for causing the rotating shaft to generate a rotating shaft backward force; a forward and backward movement control position sensor for controlling the forward and backward movement of the rotating shaft; and a wear amount detection position sensor for detecting the wear amount of the plurality of cutter blades. The control unit includes a grinding control unit for controlling the grinding process performed on the plurality of cutter blades respectively before the action of cutting the resin into pellets is performed. The grinding control unit includes: a first position acquisition unit, which acquires a first position of a tool head equipped with a plurality of tool blades based on an output from a position sensor for detecting the amount of wear; a second position acquisition unit, which acquires a second position of the tool head after the grinding process is performed for a predetermined time based on an output from the position sensor for detecting the amount of wear; a difference calculation unit, which calculates the difference between the first position and the second position; a comparison unit, which compares the difference with a preset set value; and a judgment unit, which judges whether to end the grinding process based on the comparison result of the difference and the set value.

[0017] Effects of the Invention

[0018] According to one embodiment, the adjustment of the rotary shaft retraction force or the grinding process which is a component of the blade pressing force in the resin cutting device can be automated. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a diagram showing a schematic configuration of a granulation system.

[0020] Figure 2 It is a diagram showing a schematic configuration of a resin cutting device.

[0021] Figure 3 It is a top view showing a schematic configuration example of a mold.

[0022] Figure 4 It is a plan view showing a schematic configuration example of a tool head.

[0023] Figure 5 It is a diagram showing a schematic configuration of a main part of the resin cutting device.

[0024] Figure 6 This is a diagram for explaining an example of the operation of the control unit.

[0025] Figure 7 It is a diagram showing a schematic configuration of a resin cutting device in a specific embodiment.

[0026] Figure 8 This is a diagram for explaining the division of the operating range of the wear amount detection position sensor and the operating range of the front-rear movement control position sensor.

[0027] Fig. 9 This is a functional block diagram of the rotary axis retraction force control unit.

[0028] Fig.10 is a flowchart showing the flow of the first control action example.

[0029] Fig.11 is a flowchart showing the flow of the second control action example.

[0030] Fig.12 This is a functional block diagram of the control unit.

[0031] Fig.13 This is a functional block diagram of the grinding control unit.

[0032] Fig.14 This is a flowchart showing the flow of the control operation of the grinding process. DETAILED DESCRIPTION

[0033] In all the drawings for explaining the embodiments, the same reference numerals are given to the same components in principle, and their repeated descriptions are omitted. It should be noted that, in order to make the drawings clear and easy to understand, hatching may be given even in top views.

[0034] <Granulation system>

[0035] Figure 1 It is a diagram showing a schematic configuration of a granulation system.

[0036] The granulation system 100 includes a granulator 10 including an extruder 1 and a resin cutting device 2 , a pipe 4 , a pump 5 , a dehydrator 6 , a container 7 , a centrifugal dehydration dryer 8 , and a vibrating screen 9 .

[0037] The extruder 1 is configured to knead a resin raw material 20 by a rotating screw and extrude the kneaded resin from a plurality of nozzles provided in a die of the resin cutting device 2 .

[0038] The resin cutting device 2 is configured to produce pellets by cutting, with a plurality of cutter blades, molten resin extruded from a plurality of nozzles provided in a die.

[0039] The pipe 4 is used as a flow path for allowing warm water (fluid) to flow. In addition, the pump 5 has a function of circulating the warm water flowing through the pipe 4. Furthermore, the container 7 is a storage tank for storing warm water.

[0040] The dehydrator 6 has a function of separating the granules from the warm water, and the centrifugal dehydration dryer 8 has a function of further drying the granules. The vibration screen 9 is configured to separate the granules by size.

[0041] The granulation system 100 constructed as described above operates in the following manner. That is, first, the resin raw material 20 is supplied to the extruder 1. Then, after the resin raw material 20 supplied to the extruder 1 is kneaded by the screw, the molten resin is extruded from a plurality of nozzles provided in the mold. The extruded resin is cut by a plurality of knife edges provided in the resin cutting device 2. The resin cutting is performed inside a flow path chamber where warm water flows. Thus, the molten resin is cut into pellets 30 of a predetermined size and then solidified by warm water cooling. In this way, solidified pellets 30 are manufactured by the granulator 10 including the extruder 1 and the resin cutting device 2.

[0042] Here, the warm water is circulated between the container 7 and the flow path chamber by the pipe 4 and the pump 5. As a result, the slurry 3 as a mixture of the particles 30 and the warm water generated in the flow path chamber is transported to the dehydrator 6 via the pipe 4. In the dehydrator 6, the particles 30 and the warm water are separated, and the warm water flows back to the container 7. On the other hand, the slurry 3 as a mixture of a small amount of warm water and the particles 30 is transported to the centrifugal dehydration dryer 8. In the centrifugal dehydration dryer 8, a small amount of warm water attached to the particles 30 is separated. And, the particles 30 separated from the small amount of warm water and dried at the centrifugal dehydration dryer 8 are transported to the vibrating screen 9, and the small amount of warm water separated at the centrifugal dehydration dryer 8 flows back to the container 7. Thereafter, in the vibrating screen 9, the particles 30 are separated by size.

[0043] In the above manner, the granulation system 100 can produce the granules 30 .

[0044] <Basic structure of resin cutting device>

[0045] Next, the structure of the resin cutting device 2 which is a component of the granulation system 100 will be described.

[0046] Figure 2 It is a diagram showing a schematic configuration of a resin cutting device.

[0047] exist Figure 2 In the embodiment, the resin cutting device 2 includes a mold 50, a cutter head 51, a rotating shaft 52, a motor 53, a sleeve 54, a housing 55, a flow path chamber 60, an inlet 60a, and an outlet 60b.

[0048] The die 50 is provided on the resin discharge side of an extruder for kneading and extruding the resin, and is provided with a plurality of nozzles. The resin extruded from the extruder is discharged from each of the plurality of nozzles.

[0049] The cutter head 51 is disposed so as to be pressed against the mold 50 and is provided with a plurality of cutter blades. The plurality of cutter blades have a function of cutting the resin discharged from the plurality of nozzles provided in the mold 50 into particles.

[0050] Moreover, the rotating shaft 52 is attached to the tool head 51, and the motor 53 is attached to the rotating shaft 52. As a result, since the tool head 51 is attached to the rotating shaft 52 rotated by the motor 53, it is comprised so that rotation is possible.

[0051] A sleeve 54 is provided around the rotating shaft 52 so as to be slidable in the axial direction of the rotating shaft 52, and a housing 55 is provided outside the sleeve 54. Here, the rotating shaft 52 is configured to be rotatable relative to the sleeve 54, but cannot be relatively moved relative to the sleeve 54 in the axial direction of the rotating shaft 52. That is, the rotating shaft 52 and the sleeve 54 are configured to move integrally in the axial direction of the rotating shaft 52. The sleeve 54 is configured to be relatively moved relative to the housing 55 in the axial direction of the rotating shaft 52.

[0052] The flow path chamber 60 constitutes a flow path space connected to the cutter head 51. The flow path chamber 60 is provided with an inlet 60a for allowing a fluid such as warm water to flow in, and an outlet for allowing the fluid and particles to flow out of the flow path chamber 60.

[0053] <<Example of mold configuration>>

[0054] Figure 3 It is a top view showing a schematic configuration example of a mold.

[0055] exist Figure 3 In the embodiment, for example, the planar shape of the die 50 is a substantially circular shape, and has a plurality of nozzles 50a. The resin kneaded and melted by the extruder is discharged from each of the plurality of nozzles 50a.

[0056] <<Tool head configuration example>>

[0057] Figure 4 It is a plan view showing a schematic configuration example of a tool head.

[0058] exist Figure 4 In the embodiment, for example, the planar shape of the tool head 51 is substantially circular, and the tool head 51 is provided with a plurality of tool blades 51a. The planar shape of each of the plurality of tool blades 51a is substantially rectangular.

[0059] The cutter head 51 is configured to rotate while being pressed against the mold 50 , whereby the resin discharged from the plurality of nozzles 50 a provided in the mold 50 is cut by the plurality of cutter blades 51 a provided in the cutter head 51 .

[0060] <Basic operation of resin cutting device>

[0061] The resin cutting device 2 is constructed as described above. Figure 2 Describe its action.

[0062] First, the resin kneaded by the extruder is discharged in a molten state from a plurality of nozzles provided in a die 50 to a flow path chamber 60. The discharged molten resin is cut by a plurality of tool blades provided in a tool head 51, wherein the tool head 51 is mounted on a rotating shaft 52 rotated by a motor 53 and rotates at a high speed. Then, the cut resin is cooled and solidified by warm water flowing in from an inlet 60a of the flow path chamber 60, thereby generating particles. Here, as the warm water flowing into the flow path chamber 60 flows out from an outlet 60b of the flow path chamber 60, the generated particles are also discharged from the outlet 60b. A slurry as a mixture of the discharged warm water and the particles, for example, Figure 1 As shown, it is transported to the dehydrator 6 via the pipe 4. The subsequent operation is as for Figure 1 The operation of the granulation system shown is performed as described above. As described above, in the resin cutting device 2, solidified pellets can be produced by cutting the molten resin.

[0063] <Necessity of controlling the pressure of the tool edge>

[0064] Here, it is necessary to control the pressure of the multiple tool blades provided on the tool head 51 against the mold 50 to an appropriate constant value. The reason is that when the tool blades are pressed against the mold 50, the tool blades are worn. Therefore, if the pressure of the tool blades pressing against the mold is too large, the wear of the tool blades increases. On the other hand, if the pressure of the tool blades pressing against the mold is small, the tool blades will be separated from the mold, which will cause a cutting failure that cannot normally cut the resin into particles. Therefore, the resin cutting device 2 has a structure for controlling the pressure of the tool blades to be constant. This structure is described below.

[0065] <Structure for controlling the pressing force of the tool edge>

[0066] exist Figure 2 In the embodiment, the resin cutting device 2 includes a control unit 70 , a rotation axis forward force generating unit 80 , and a rotation axis backward force generating unit 90 .

[0067] The rotating shaft advancing force generating unit 80 is configured to generate a rotating shaft advancing force Ff for the rotating shaft 52. For example, the rotating shaft advancing force generating unit 80 is configured to generate the rotating shaft advancing force using the pressure of the pressure medium injected into the first gap chamber. Specifically, the product of the pressure receiving area of ​​the first gap chamber and the pressure based on the pressure medium becomes the rotating shaft advancing force Ff. The rotating shaft advancing force Ff is a force in the direction in which the rotating shaft 52 (sleeve 54) approaches the mold 50, and is a force generated by the rotating shaft advancing force generating unit 80.

[0068] The rotating shaft retreat force generating unit 90 is configured to generate a rotating shaft retreat force Fb on the rotating shaft 52. For example, the rotating shaft retreat force generating unit 90 is configured to generate the rotating shaft retreat force using the pressure of the pressure medium injected into the second gap chamber. Specifically, the product of the pressure receiving area of ​​the second gap chamber and the pressure based on the pressure medium becomes the rotating shaft retreat force Fb. The rotating shaft retreat force Fb is a force in the direction of moving the rotating shaft 52 (sleeve 54) away from the mold 50, and is a force generated by the rotating shaft retreat force generating unit 90.

[0069] The control unit 70 is configured to control the tool blade pressing force for pressing the plurality of tool blades against the die 50 , and includes a rotation speed control unit 71 , a rotation axis forward force control unit 72 , and a rotation axis backward force control unit 73 .

[0070] The rotation speed control unit 71 is configured to control the rotation speed of the rotating shaft 52. Specifically, the rotation speed control unit 71 is configured to control the rotation speed of the rotating shaft 52 by controlling the rotation of the motor 53 to which the rotating shaft 52 is attached.

[0071] The rotating shaft advancing force control unit 72 is configured to control the rotating shaft advancing force Ff by adjusting the pressure of the pressure medium injected into the first gap chamber.

[0072] The rotating shaft retreat force control unit 73 is configured to control the rotating shaft advancing force Fb by adjusting the pressure of the pressure medium injected into the second gap chamber.

[0073] The control unit 70 configured in this manner is configured to perform control so that the tool edge pressing force represented by the following relational expression becomes constant, for example.

[0074] Specifically, when the tool blade pressing force is set to F, the forward force of the rotating shaft is set to Ff, the tool blade propulsion force generated by the rotation of multiple tool blades and the magnitude of which varies according to the rotation speed of the rotating shaft is set to Fs, the retraction force of the rotating shaft is set to Fb, the retraction force caused by the fluid pressure of the fluid filled in the flow path chamber is set to Fw, and the sliding resistance caused by the advancement or retraction of the rotating shaft is set to Fr, the tool blade pressing force F is expressed by F=Ff+Fs-Fb-Fw±Fr.

[0075] For example, Figure 5 1 is a diagram showing a schematic configuration of the main parts of the resin cutting device. Figure 5 , the rotation axis forward force is denoted as Ff, the tool blade thrust force is denoted as Fs, and the rotation axis retract force is denoted as Fb, and the retract force Fw and the sliding resistance Fr caused by the fluid pressure of the fluid filling the flow path chamber are illustrated.

[0076] Here, "Fw" and "Fr" are basically constant values ​​(constants) determined by the structure of the resin cutting device 2 and can be estimated in advance. Therefore, the control unit 70 of the resin cutting device 2 controls so that the value of "Ff+Fs-Fb" is constant in order to keep the blade pressing force F constant. The following describes an example of the operation of the control unit 70.

[0077] <Operation Example of Control Unit 70>

[0078] Figure 6 It is a diagram for explaining an example of the operation of the control unit 70 .

[0079] exist Figure 6 In FIG. 5 , the horizontal axis represents the rotation speed (Nc) of the rotating shaft, and the vertical axis represents the force. First, after the control unit 70 operates the motor 53, the rotation speed Nc of the rotating shaft 52 also increases in accordance with the increase in the motor speed. Here, the rotation speed Nc of the rotating shaft 52 is adjusted in accordance with the resin production of the granulator 10. That is, when the resin production of the granulator 10 is small, the rotation speed Nc of the rotating shaft 52 decreases, and when the resin production of the granulator 10 is large, the rotation speed Nc of the rotating shaft 52 increases. Here, the tool blade thrust force Fs has a characteristic of increasing as the rotation speed Nc of the rotating shaft 52 increases.

[0080] Therefore, in order to keep "Ff+Fs-Fb" constant even if the rotation speed Nc changes, it is necessary to control the rotation axis forward force Ff and the rotation axis backward force Fb. Figure 6 As shown, as the rotation speed Nc of the rotating shaft 52 increases, the rotating shaft forward force control unit 72 reduces the rotating shaft forward force Ff to offset the increase in the tool blade thrust force Fs. In addition, the rotating shaft retracting force control unit 73 controls so that even if the rotation speed Nc of the rotating shaft 52 changes, the rotating shaft retracting force Fb is also a constant value. Here, the reason why the rotating shaft retracting force control unit 73 controls so that even if the rotation speed Nc of the rotating shaft 52 changes, the rotating shaft retracting force Fb is also a constant value is because the stability of the control and the simplicity of the adjustment are emphasized. That is, if the rotating shaft forward force Ff is variably controlled by the rotating shaft forward force control unit 72, and the rotating shaft retracting force Fb is also variably controlled by the rotating shaft retracting force control unit 73, the control will be complicated. Therefore, if the rotating shaft forward force Ff can be reduced by the rotating shaft forward force control unit 72 to offset the increase in the tool blade thrust force Fs, there is no need to variably control the rotating shaft retraction force Fb by the rotating shaft retraction force control unit 73, and control stability and ease of adjustment can be achieved.

[0081] Like this, according to Figure 6 The illustrated operation example of the control unit 70 can maintain the tool edge pressing force F constant even if the rotation speed Nc of the rotary shaft 52 changes.

[0082] <Improvement Discussion>

[0083] As described above, as the rotation speed Nc of the rotary shaft 52 increases, the tool blade thrust Fs also increases. Therefore, in order to offset the increase in the tool blade thrust Fs, the rotary shaft forward force control unit 72 controls so that the rotary shaft forward force Ff decreases. Figure 6 In the figure, for easy-to-understand description, an example is shown in which the rotating shaft forward force Ff decreases in the form of a linear function as the rotation speed Nc of the rotating shaft 52 increases.

[0084] However, in reality, the rotation axis advancement force control unit 72 controls the rotation axis advancement force Ff so that the sum of the rotation axis advancement force Ff and the tool blade advancement force Fs is constant according to the rotation speed Nc of the rotation axis 52 based on a curve represented by a quadratic function called a "pressing curve". That is, the "pressing curve" is a relational expression for controlling so that the sum of the rotation axis advancement force Ff and the tool blade advancement force Fs is a constant value even if the rotation speed Nc of the rotation axis 52 changes. Through the control of the rotation axis advancement force control unit 72 based on the "pressing curve", the tool blade is pressed against the mold 50 with a substantially constant force at any rotation speed Nc.

[0085] As described above, although the tool blade pressing force F is controlled to be constant, as the resin cutting action continues in the resin cutting device, there is a case where the tool blade pressing force F deviates from the constant value due to various factors. In this case, there is a possibility of failure due to abnormal wear of the tool blade or poor cutting. In this regard, in the case where the tool blade pressing force F deviates from the constant value, it can be considered to adjust the rotating shaft forward force Ff so that the tool blade pressing force F is an appropriate value. However, since it is desirable to maintain the relationship between the rotating shaft forward force Ff and the tool blade thrust force Fs ("pressing curve"), the tool blade pressing force F is adjusted to an appropriate value by changing the rotating shaft retracting force Fb without changing the rotating shaft forward force Ff. The adjustment of the rotating shaft retracting force Fb is performed manually.

[0086] Specifically, the worker performs the following work.

[0087] (1) Check the wear of the tool edge (every day, every half day).

[0088] (2) Determine whether the amount of wear is appropriate or abnormal.

[0089] (3) Determine whether to increase or decrease the value of the rotating shaft retreat force Fb.

[0090] (4) Determine to what extent the value of the rotation axis retreat force Fb is changed.

[0091] (5) Return to (1) and repeat.

[0092] Therefore, if the rotary shaft retraction force Fb is manually adjusted, it is necessary to regularly investigate and record the wear amount of the tool blade, which requires labor and time. In addition, the accuracy of the adjustment varies depending on the proficiency of the worker. Therefore, in this embodiment, consideration is taken to reduce the workload of the worker and adjust the rotary shaft retraction force Fb without relying on the worker's skills. The technical idea in this embodiment in which this consideration is taken is described below.

[0093] <Basic Concept of Implementation>

[0094] The basic idea in this embodiment is a technical idea about the control technology of a resin cutting device that produces pellets by cutting a resin discharged from an extruder that kneads and extrude the resin. In addition, the basic idea is such an idea that after detecting the wear amount of the plurality of tool blades, the magnitude of the rotary shaft retreat force Fb applied to the rotary shaft is automatically controlled according to the detected wear amount of the plurality of tool blades in the technical idea of ​​controlling the pressure of the tool blades that press the plurality of tool blades that cut the resin into pellets to a die provided on the resin discharge side of the extruder.

[0095] Specifically, the control method of the resin cutting device in this embodiment includes: a wear amount detection process, detecting the wear amount of multiple tool blades during the operation of the resin cutting device to cut the resin into particles; a rotating shaft retraction force control process, controlling the magnitude of the rotating shaft retraction force Fb applied to the rotating shaft installed on the tool head equipped with multiple tool blades according to the wear amount of the multiple tool blades detected by the wear amount detection process.

[0096] Thus, according to the basic idea, the adjustment of the rotary shaft retreat force, which was previously adjusted manually, can be automated by providing a wear amount detection process and a rotary shaft retreat force control process. As a result, according to the basic idea, the magnitude of the rotary shaft retreat force Fb can be adjusted to an appropriate value without relying on the skill level of the worker. Thus, according to the basic idea, since the tool blade pressing force F can be automatically controlled to be constant, the occurrence of faults caused by abnormal wear of the tool blade and poor cutting can be suppressed. Therefore, according to the basic idea, in a particle manufacturing method for cutting resin to manufacture particles, the shortening of the life of the tool blade and the reduction in the quality of the manufactured particles can be suppressed.

[0097] The following describes a specific implementation method for realizing the basic idea.

[0098] <Specific implementation method>

[0099] The above basic idea is characterized in that it is an idea that includes a wear amount detection process and a rotary shaft retreat force control process. When the basic idea is specifically implemented, the specific implementation of the wear amount detection process and the specific implementation of the rotary shaft retreat force control process are required. Therefore, the specific implementation of the wear amount detection process and the specific implementation of the rotary shaft retreat force control process are described below.

[0100] <<Specific implementation method of the wear amount detection process>>

[0101] If the tool blade pressing force F deviates from the appropriate value, abnormal wear of the tool blade and poor cutting will occur. In this regard, abnormal wear of the tool blade and poor cutting are judged based on the wear amount of the tool blade. Therefore, in order to judge the situation where abnormal wear of the tool blade and poor cutting occur, it is necessary to detect the wear amount of the tool blade. Therefore, in a specific embodiment, for example, in order to detect the wear amount of the tool blade, a wear amount detection position sensor is used. Specifically, the wear amount detection position sensor is set on the rotating shaft in a manner linked to the forward and backward movement of the rotating shaft. Thus, the position of the tool head mounted on the rotating shaft can be detected by the wear amount detection position sensor. That is, during the operation of the resin cutting device that cuts the resin into particles, a plurality of tool blades arranged on the rotating tool head are pressed against the mold. Therefore, the tool blade is worn, and the position of the tool head changes due to the wear of the tool blade. And the change in the position of the tool head means that the position of the rotating shaft mounted on the tool head changes. In this regard, if a wear amount detection position sensor is set on the rotating shaft, the position of the rotating shaft and the position of the tool head mounted on the rotating shaft can be detected by the wear amount detection position sensor. This means that the wear amount of the tool edge can be detected indirectly by the position of the tool head. As described above, in a specific embodiment, the wear amount of the tool edge is detected by installing a wear amount detection position sensor that is linked to the forward and backward movement of the rotating shaft on the rotating shaft.

[0102] Here, the rotating shaft is provided with a forward and backward movement control position sensor linked to the forward and backward movement of the rotating shaft. That is, in order to make a plurality of tool blades arranged on the tool head contact and separate with the mold, the rotating shaft installed on the tool head is moved forward and backward. Here, the forward and backward movement of the rotating shaft is controlled based on the output from the forward and backward movement control position sensor. Therefore, it is conceivable to use the forward and backward movement control position sensor that has been provided as a wear amount detection position sensor.

[0103] However, according to the inventor's research, it is found that it is difficult to use the position sensor for forward and backward movement control as a position sensor for wear detection. This point is explained below. For example, the position sensor for forward and backward movement control is constructed to detect the range of ±8mm as the starting point of the forward and backward movement, and the detection position accuracy is about 0.1mm. In contrast, the wear of the tool blade needs to be accurately detected with an accuracy of 0.01mm, and the resolution of the position sensor for forward and backward movement control cannot be said to be sufficient. That is, in order to detect the wear of the tool blade, it is necessary to accurately monitor the position of the tool head (the position of the rotating shaft) in units of 0.01mm, and there is a concern that the position sensor for forward and backward movement control has insufficient resolution. In addition, if the monitoring of the position of the tool head (the position of the rotating shaft) is inaccurate, the automatic control of the rotating shaft retraction force Fb will not work properly and cause malfunction, which becomes the cause of the failure.

[0104] Therefore, in a specific embodiment, in addition to the position sensor for forward and backward movement control, a position sensor for detecting the amount of wear of the tool blade is also provided. That is, the resin cutting device is provided with a position sensor for forward and backward movement control and a position sensor for detecting the amount of wear as position detection sensors. In particular, the position detection accuracy of the position sensor for detecting the amount of wear is higher than that of the position sensor for forward and backward movement control. Specifically, the position detection accuracy of the position sensor for forward and backward movement control is at the level of 0.1 mm, while the position detection accuracy of the position sensor for detecting the amount of wear is at the level of 0.01 mm. Thus, in a specific embodiment, the amount of wear of the tool blade, which is a tiny amount, can be detected with high accuracy.

[0105] Next, a configuration example of a resin cutting device equipped with a wear amount detection position sensor will be described.

[0106] Figure 7 2 is a diagram showing a schematic configuration of a resin cutting device 2 in a specific embodiment. Figure 7 In the embodiment, a wear amount detection position sensor 200A is provided on the rotating shaft 52. The wear amount detection position sensor 200A includes a detection plate 201, and the detection plate 201 is movably mounted on the rotating shaft 52 so as to follow the front-rear movement of the rotating shaft 52. The wear amount detection position sensor 200A is configured to detect the position of the rotating shaft 52 (the position of the tool head) using the detection plate 201 that follows the front-rear movement of the rotating shaft 52.

[0107] It should be noted that the resin cutting device 2 is also provided with a forward and backward movement control position sensor having the same structure as the wear amount detection position sensor 200A, but in Figure 7 This forward and backward movement control position sensor is also configured to detect the position of the rotation shaft using a detection plate.

[0108] Figure 8 2 is a diagram for explaining the division of the operating range of the wear amount detection position sensor 200A and the operating range of the front-rear movement control position sensor 200B. Figure 8 In the embodiment, the wear amount detection position sensor 200A is configured to detect the position of the tool head 51 using the detection plate 201, and is configured to detect the vicinity of the contact area between the tool head 51 and the mold 50 ( Figure 8 The position of the tool head 51 in the area indicated by the arrow 1).

[0109] On the other hand, the forward and backward movement control position sensor 200B is also configured to detect the position of the tool head 51 using the detection plate 201, and is configured to detect Figure 8 The position of the tool head 51 in the area indicated by arrow 2.

[0110] In other words, in the resin cutting device of the specific embodiment, the position of the tool head 51 is detected by the wear amount detection position sensor 200A in the vicinity of the contact between the tool head 51 and the mold 50, so that the wear amount of the tool edge can be detected with high accuracy.

[0111] <<Specific implementation method of the rotary axis retreat force control process>>

[0112] Next, a specific embodiment of the rotating shaft retreat force control process will be described.

[0113] Fig. 9 2 is a functional block diagram of the rotating shaft retreat force control unit 73 .

[0114] exist Fig. 9 In FIG. 7 , the rotating axis backward force control unit 73 includes an input unit 300 , a first position acquisition unit 301 , a second position acquisition unit 302 , a difference calculation unit 303 , a comparison unit 304 , a rotating axis backward force setting unit 305 , and a data storage unit 306 .

[0115] The input unit 300 is configured to input output data from the wear amount detection position sensor 200A, for example. In addition, the input unit 300 is configured to input a preset wear amount upper limit value. And the output data from the wear amount detection position sensor 200A and the preset wear amount upper limit value input to the input unit 300 are stored in the data storage unit 306. That is, the data storage unit 306 has a function of storing various data.

[0116] The first position acquisition unit 301 is configured to acquire the "first position" of the tool head provided with a plurality of tool blades based on the output data from the wear amount detection position sensor 200A stored in the data storage unit 306. Here, the "first position" means the position where the tool head is arranged when the tool head is brought into contact with the surface of the mold. The data related to the "first position" acquired by the first position acquisition unit 301 is stored in the data storage unit 306.

[0117] The second position acquisition unit 302 is configured to acquire the "second position" of the tool head provided with a plurality of tool blades based on the output data from the wear amount detection position sensor 200A stored in the data storage unit 306. Here, the "second position" refers to the position where the tool head is provided after the resin cutting operation by the resin cutting device has been performed for a predetermined time. The data related to the "second position" acquired by the second position acquisition unit 302 is stored in the data storage unit 306.

[0118] The difference calculation unit 303 is configured to calculate the difference between the "first position" and the "second position" based on the "first position" and the "second position" stored in the data storage unit 306. The difference between the "first position" and the "second position" is equivalent to the wear amount of the tool edge. That is, the difference calculation unit 303 calculates the wear amount of the tool edge by calculating the difference between the "first position" and the "second position". Data on the difference between the "first position" and the "second position" equivalent to the wear amount is stored in the data storage unit 306.

[0119] It should be noted that although the difference calculation unit 303 calculates the wear amount after the resin cutting action performed by the resin cutting device is performed for a predetermined time, for example, the difference calculation unit 303 can also have a function of estimating the wear amount corresponding to a time corresponding to several times the predetermined time.

[0120] Specifically, the difference between the "first position" and the "second position" calculated by the difference calculation unit 303 is equivalent to the amount of wear after the resin cutting action is performed for a predetermined time. By multiplying the difference by a certain multiple, the amount of wear after the resin cutting action is performed for a certain multiple of the predetermined time can be estimated. For example, if the difference between the "first position" and the "second position" calculated by the difference calculation unit 303 is the amount of wear after the resin cutting action is performed for two hours, the difference calculation unit 303 is configured to calculate the amount of wear after the resin cutting action is performed for 2×12=24 hours by multiplying the difference by 12 times.

[0121] The comparison unit 304 is configured to compare the difference between the "first position" and the "second position" stored in the data storage unit 306 with the wear amount upper limit value stored in the data storage unit 306, for example. In other words, the comparison unit 304 is configured to compare the wear amount after the resin cutting action is performed for a predetermined time with the wear amount upper limit value, and determine whether the wear amount after the resin cutting action is performed for a predetermined time is greater than the wear amount upper limit value, or whether it is less than the wear amount upper limit value. Then, the comparison result of the comparison unit 304 is stored in the data storage unit 306.

[0122] It should be noted that the comparison unit 304 may be configured to compare the wear amount after the resin cutting action is performed for a predetermined time with a certain multiple of the wear amount upper limit value. In this case, based on the comparison result of the comparison unit 304, it can be understood that abnormal wear (a certain multiple of the wear amount upper limit value) has occurred in which the wear amount is very large after the resin cutting action is performed for a predetermined time.

[0123] The rotating shaft retraction force setting unit 305 is configured to set the magnitude of the rotating shaft retraction force applied to the rotating shaft according to the comparison result of the comparison unit 304. For example, in the case where the comparison result of the comparison unit 304 is "the amount of wear after the resin cutting action is performed for a predetermined time>the upper limit of the wear amount", the risk of excessive wear is high. Therefore, the rotating shaft retraction force setting unit 305 is configured to increase (increase) the magnitude of the rotating shaft retraction force. On the other hand, in the case where the comparison result of the comparison unit 304 is "the amount of wear after the resin cutting action is performed for a predetermined time<the upper limit of the wear amount", the rotating shaft retraction force setting unit 305 is configured to reduce (reduce) the magnitude of the rotating shaft retraction force. In addition, in the case where the comparison result of the comparison unit 304 is "the amount of wear after the resin cutting action is performed for a predetermined time=the upper limit of the wear amount", the rotating shaft retraction force setting unit 305 is configured to maintain the magnitude of the rotating shaft retraction force as it is. Furthermore, setting information on the magnitude of the rotating axis retreat force set by the rotating axis retreat force setting unit 305 is stored in the data storage unit 306 .

[0124] Next, the rotating axis backward force control unit 73 is configured to control the rotating axis backward force applied to the rotating axis according to the magnitude of the rotating axis backward force set by the rotating axis backward force setting unit 305. That is, the rotating axis backward force control unit 73 is configured to control the rotating axis backward force applied to the rotating axis according to the setting information of the magnitude of the rotating axis backward force stored in the data storage unit 306. The rotating axis backward force control unit 73 is configured as described above.

[0125] <<Control action of the rotary axis backward force (control method)>>

[0126] Next, an example of the control operation of the rotary axis retreat force will be described.

[0127] Hereinafter, an example of the control operation of the two rotation axis retreat forces will be described.

[0128] (1) Example of the first control action

[0129] Fig.10 is a flowchart showing the flow of the first control action example.

[0130] exist Fig.10 In the embodiment, first, as a premise, the preset upper limit value of the wear amount is stored in the data storage unit 306. Then, the control unit 70 of the resin cutting device 2 moves the rotating shaft 52 forward according to the output of the position sensor 200B for forward and backward movement control and the output of the position sensor 200A for wear amount detection, so that the tool head 51 mounted on the rotating shaft 52 contacts the mold 50 (S101). For example, the control unit 70 moves the rotating shaft 52 forward with a certain pressure to contact the tool head 51 with the mold 50. Here, the position of the rotating shaft 52 until the tool head 51 is about to contact the mold 50 is detected by the position sensor 200B for forward and backward movement control, and then, the position of the rotating shaft 52 until the tool head 51 contacts the mold 50 is switched to the wear amount detection position sensor 200A having a higher position detection accuracy than the position sensor 200B for forward and backward movement control.

[0131] Next, after the output from the wear amount detection position sensor 200A is input to the input unit 300 of the rotary shaft retraction force control unit 73, the input output data of the wear amount detection position sensor 200A is stored in the data storage unit 306. Then, the first position acquisition unit 301 acquires (S102) the “first position” of the tool head 51 based on the output data of the wear amount detection position sensor 200A stored in the data storage unit 306. The acquired “first position” of the tool head 51 is stored in the data storage unit 306.

[0132] Thereafter, the resin cutting operation is performed for two hours in the resin cutting device 2 (S103). As a result, the wear of the plurality of tool blades disposed on the tool head 51 is aggravated. Thereafter, the output from the wear amount detection position sensor 200A is input to the input unit 300 of the rotary shaft retraction force control unit 73, and then the input output data of the wear amount detection position sensor 200A is stored in the data storage unit 306. Then, the second position acquisition unit 302 acquires (S104) the "second position" of the tool head 51 based on the output data of the wear amount detection position sensor 200A stored in the data storage unit 306. The acquired "second position" of the tool head 51 is stored in the data storage unit 306.

[0133] Next, the difference calculation unit 303 inputs the "first position" and the "second position" stored in the data storage unit 306, and then calculates the difference between the "first position" and the "second position". This difference is equivalent to the wear amount of the tool blade in two hours. In addition, the difference calculation unit 303 multiplies the calculated wear amount of the tool blade in two hours by 12 times to calculate the wear amount converted to one day (S105). The wear amount converted to one day is stored in the data storage unit 306.

[0134] Next, the comparison unit 304 inputs the amount of wear converted to one day and the upper limit of the wear amount stored in the data storage unit 306, and then compares the input amount of wear converted to one day with the upper limit of the wear amount × 10 (S106). Then, the rotating shaft retraction force setting unit 305 sets the magnitude of the rotating shaft retraction force Fb according to the comparison result of the comparison unit 304. Specifically, when the comparison result of the comparison unit 304 is "the amount of wear converted to one day ≥ the upper limit of the wear amount × 10", the rotating shaft retraction force setting unit 305 determines that abnormal wear has occurred, and sets the magnitude of the rotating shaft retraction force to be increased (sets to increase) (S107). On the other hand, when the comparison result of the comparison unit 304 is "the amount of wear converted to one day < the upper limit of the wear amount × 10", the rotating shaft retraction force setting unit 305 determines that abnormal wear has not occurred, and sets the magnitude of the rotating shaft retraction force to be maintained at the current state (S108). It should be noted that these setting information is stored in the data storage unit 306.

[0135] Then, the rotating shaft retreat force control unit 73 controls the rotating shaft retreat force Fb according to the setting information stored in the data storage unit 306 (S109). For example, when the setting information is an increase setting, the rotating shaft retreat force control unit 73 performs control to increase the rotating shaft retreat force Fb. On the other hand, when the setting information is a maintain status setting, the rotating shaft retreat force control unit 73 performs control to maintain the rotating shaft retreat force Fb at the status quo.

[0136] Thereafter, when the resin cutting operation of the resin cutting device 2 is terminated (S110), the control unit 70 performs control to terminate the resin cutting operation of the resin cutting device 2. On the other hand, when the resin cutting operation of the resin cutting device 2 is continued, the process returns to S102 and the same operation is repeated.

[0137] As described above, according to the first control operation example, the wear amount can be determined for two hours, and abnormal wear (10 times the wear amount upper limit value) can be automatically detected as soon as possible.

[0138] (2) Example of the second control action

[0139] Fig.11is a flowchart showing the flow of the second control action example.

[0140] exist Fig.11 In the embodiment, first, as a premise, a preset wear amount standard value is stored in the data storage unit 306. Then, the control unit 70 of the resin cutting device 2 advances the rotating shaft 52 according to the output of the position sensor 200B for forward and backward movement control and the output of the position sensor 200A for wear amount detection, so that the tool head 51 mounted on the rotating shaft 52 contacts the mold 50 (S201). For example, the control unit 70 advances the rotating shaft 52 at a certain pressure to contact the tool head 51 with the mold 50. Here, the position of the rotating shaft 52 until the tool head 51 is about to contact the mold 50 is detected by the position sensor 200B for forward and backward movement control, and then, the position of the rotating shaft 52 until the tool head 51 contacts the mold 50 is switched to the wear amount detection position sensor 200A having a higher position detection accuracy than the position sensor 200B for forward and backward movement control.

[0141] Next, after the output from the wear amount detection position sensor 200A is input to the input unit 300 of the rotary shaft retraction force control unit 73, the input output data of the wear amount detection position sensor 200A is stored in the data storage unit 306. Then, the first position acquisition unit 301 acquires (S202) the “first position” of the tool head 51 based on the output data of the wear amount detection position sensor 200A stored in the data storage unit 306. The acquired “first position” of the tool head 51 is stored in the data storage unit 306.

[0142] Thereafter, the resin cutting operation is performed for 24 hours in the resin cutting device 2 (S203). As a result, the wear of the plurality of tool blades arranged on the tool head 51 is aggravated. Thereafter, the output from the wear amount detection position sensor 200A is input to the input unit 300 of the rotary shaft retraction force control unit 73, and then the input output data of the wear amount detection position sensor 200A is stored in the data storage unit 306. Then, the second position acquisition unit 302 acquires (S204) the "second position" of the tool head 51 based on the output data of the wear amount detection position sensor 200A stored in the data storage unit 306. The acquired "second position" of the tool head 51 is stored in the data storage unit 306.

[0143] Next, the difference calculation unit 303 inputs the "first position" and the "second position" stored in the data storage unit 306, and then calculates the difference between the "first position" and the "second position". The difference is equivalent to the wear amount of the tool edge in one day. The difference between the "first position" and the "second position" equivalent to the wear amount in one day is stored in the data storage unit 306.

[0144] Next, the comparison unit 304 inputs the wear amount of one day and the wear amount standard value stored in the data storage unit 306, and then compares the input wear amount of one day with the wear amount standard value (S206). Then, the rotating shaft retraction force setting unit 305 sets the magnitude of the rotating shaft retraction force Fb according to the comparison result of the comparison unit 304. Specifically, when the comparison result of the comparison unit 304 is "the wear amount of one day>the wear amount standard value", the rotating shaft retraction force setting unit 305 determines that abnormal wear has occurred, and sets the magnitude of the rotating shaft retraction force to be increased (sets to increase) (S207). On the other hand, when the comparison result of the comparison unit 304 is not "the wear amount of one day>the wear amount standard value", but "the wear amount of one day=the wear amount standard value" (S208), it is determined that abnormal wear has not occurred, and the magnitude of the rotating shaft retraction force is maintained at the current state (S209). In addition, when the comparison result of the comparison unit 304 is not "amount of wear per day> wear amount standard value" or "amount of wear per day=wear amount standard value", that is, "amount of wear per day<wear amount standard value" (S208), the rotary axis retraction force setting unit 305 determines that there is a risk of poor cutting and sets the magnitude of the rotary axis retraction force to be reduced (S210). It should be noted that these setting information is stored in the data storage unit 306.

[0145] Then, the rotating shaft retreat force control unit 73 controls the rotating shaft retreat force Fb according to the setting information stored in the data storage unit 306 (S211). For example, when the setting information is an increase setting, the rotating shaft retreat force control unit 73 controls to increase the rotating shaft retreat force Fb. On the other hand, when the setting information is a maintain status setting, the rotating shaft retreat force control unit 73 controls to maintain the rotating shaft retreat force Fb at the status quo. In addition, when the setting information is a decrease setting, the rotating shaft retreat force control unit 73 controls to decrease the rotating shaft retreat force Fb.

[0146] Thereafter, when the resin cutting operation of the resin cutting device 2 is finished (S212), the control unit 70 performs control to finish the resin cutting operation of the resin cutting device 2. On the other hand, when the resin cutting operation of the resin cutting device 2 is continued, the process returns to S202 and the same operation is repeated.

[0147] As described above, according to the second control operation example, it is possible to determine the amount of wear for 24 hours and automatically adjust the rotating shaft retracting force Fb so that the amount of wear becomes appropriate.

[0148] <<Features of the specific embodiment>>

[0149] Next, the characteristic points in the specific implementation are described.

[0150] The first characteristic point of the specific embodiment is that the resin cutting device is provided with a position sensor for wear detection in addition to the position sensor for forward and backward movement control, thereby being able to detect the wear of the tool blade with high accuracy based on the position information of the tool head (position information of the rotating shaft) output from the position sensor for wear detection.

[0151] Here, the technical significance of providing another wear detection position sensor in addition to the forward and backward movement control position sensor is explained. For example, it is conceivable to detect the wear of the tool edge by using the position information of the tool head output from the forward and backward movement control position sensor.

[0152] However, the position sensor for forward and backward movement control is a position sensor used to control the forward and backward movement of the rotating shaft. Although it has the advantage of a wide position detection range, it has the disadvantage of insufficient position detection accuracy for detecting the amount of wear. For example, the position detection range of the position sensor for forward and backward movement control is ±8mm of the reference position, while the position detection accuracy of the position sensor for forward and backward movement control is about 0.1mm.

[0153] In this regard, detecting the amount of wear on the tool blade requires a position detection accuracy of at least about 0.01mm. Therefore, if there is a position sensor for forward and backward movement control with a position detection accuracy of about 0.01mm, the position sensor for forward and backward movement control can be used to detect the amount of wear on the tool blade, but such a position sensor does not actually exist. Therefore, in a specific embodiment, in addition to the position sensor for forward and backward movement control, a position sensor for wear detection is also provided. The position detection range of the position sensor for wear detection is 3mm forward and 1mm backward, and it has a high resolution with a position detection accuracy of about 0.01mm. Therefore, in a specific embodiment, in order to detect the amount of wear on the tool blade with high precision, in addition to the position sensor for forward and backward movement control, a position sensor for wear detection is also provided.

[0154] Next, the second characteristic point of the specific embodiment is that the magnitude of the rotary shaft retraction force applied to the rotary shaft is appropriately set by the wear amount calculated based on the output of the position sensor for wear amount detection, and the rotary shaft retraction force is automatically controlled. Therefore, according to the second characteristic point, the magnitude of the rotary shaft retraction force can be adjusted to an appropriate value regardless of the skill level of the worker. That is, according to the second characteristic point, since the pressing force of the tool blade can be automatically controlled to be constant, the occurrence of faults caused by abnormal wear of the tool blade and poor cutting can be suppressed. Therefore, according to the second characteristic point, in the particle manufacturing method of manufacturing particles by cutting resin, the shortening of the life of the tool blade and the reduction in the quality of the manufactured particles can be suppressed.

[0155] Specifically, for example, Fig. 9 As shown, the second characteristic point relates to the point that the rotary shaft retreat force control unit 73 includes an input unit 300, a first position acquisition unit 301, a second position acquisition unit 302, a difference calculation unit 303, a comparison unit 304, a rotary shaft retreat force setting unit 305, and a data storage unit 306. Thus, the magnitude of the rotary shaft retreat force can be automatically adjusted according to the output of the wear amount detection position sensor. That is, by combining the first characteristic point and the second characteristic point, automatic control of the rotary shaft retreat force can be achieved.

[0156] <Application Examples>

[0157] In the above specific embodiment, in addition to the position sensor for forward and backward movement control, the resin cutting device is also provided with a position sensor for wear amount detection, which has a higher position detection accuracy than the position sensor for forward and backward movement control. Therefore, the following will describe an application example of using a position sensor for wear amount detection with high position detection accuracy.

[0158] The resin cutting device is a device that produces pellets by rotating a plurality of cutter blades in water while constantly pressing the plurality of cutter blades at a predetermined pressure against a surface of a mold from which a linear molten resin is discharged to cut the resin.

[0159] Here, if the operation of the resin cutting device is continued, the tool blade will wear. Therefore, the tool blade needs to be replaced regularly. When replacing the tool blade, a grinding process is performed before the operation of the resin cutting device, in which the tool blade is ground by pressing the tool blade against the surface of the mold with an appropriate force while rotating it. The grinding process is performed while the worker determines the amount of wear on the tool blade based on the output signal from the position sensor for forward and backward movement control provided in the resin cutting device. Specifically, during the grinding process, the worker monitors the equipment status while manually adjusting the operating parameters such as the tool blade pressing force to press the tool blade against the surface of the mold and the grinding time.

[0160] The position sensors currently used for forward and backward movement control have the problem of fluctuations in output signals due to noise, equipment vibration, etc., and the position detection accuracy is low. Therefore, it is difficult for workers to determine whether the grinding process is being carried out properly.

[0161] Since the current grinding process is performed by manual adjustment by the worker, the pass or failure of the grinding process is affected by the worker's skill level in judging the sound when the tool blade contacts the mold, the overall cutting condition of the tool blade, and the position detection accuracy of the position sensor used for forward and backward movement control. Therefore, there is room for improvement.

[0162] In this regard, the resin cutting device in the above-mentioned specific embodiment is provided with a position sensor for detecting wear in addition to the position sensor for forward and backward movement control, which has a higher position detection accuracy than the position sensor for forward and backward movement control. Therefore, it can be imagined that by using a position sensor for detecting wear with high position detection accuracy to detect the wear of the tool blade with high accuracy, and automating the determination of the end of the grinding process based on the detected wear, it is possible to realize a resin cutting device that can properly grind the tool blade regardless of the worker's skill level and experience. In the application example, a resin cutting device (also including a granulator equipped with a resin cutting device) that uses a position sensor for detecting wear to realize the automation of the grinding process is described.

[0163] <<Functional block configuration of control unit>>

[0164] Fig.12 70 is a functional block diagram of the control unit 70. Fig.12 As shown, similarly to the specific embodiment, the control unit 70 is configured to control the blade pressing force of the plurality of blades pressing against the mold 50, and includes a rotation speed control unit 71, a rotation axis forward force control unit 72, and a rotation axis backward force control unit 73. In addition, in the application example, the control unit 70 includes a grinding control unit 74 that controls the grinding process performed on each of the plurality of blades before the action of cutting the resin into particles is performed.

[0165] Fig.13 2 is a functional block diagram of the grinding control unit 74 .

[0166] exist Fig.13 In FIG. 4 , the grinding control unit 74 includes an input unit 400 , a first position acquisition unit 401 , a second position acquisition unit 402 , a difference calculation unit 403 , a comparison unit 404 , a determination unit 405 , a display unit 406 , and a data storage unit 407 .

[0167] The input unit 400 is configured to input the output data (output signal) from the wear amount detection position sensor 200A. In addition, the input unit 400 is configured to input a preset wear amount setting value. And the output data from the wear amount detection position sensor 200A and the preset grinding amount setting value input to the input unit 400 are stored in the data storage unit 407. That is, the data storage unit 407 has a function of storing various data.

[0168] The first position acquisition unit 401 is configured to acquire the "first position" of the tool head provided with a plurality of tool blades based on the output data from the wear amount detection position sensor 200A stored in the data storage unit 407. Here, the "first position" means the position where the tool head is provided when the tool head is brought into contact with the mold surface. And the data on the "first position" is stored in the data storage unit 407.

[0169] The second position acquisition unit 402 is configured to acquire the "second position" of the tool head having a plurality of tool blades arranged therein, based on the output data from the wear amount detection position sensor 200A stored in the data storage unit 407. Here, the "second position" refers to the position where the tool head is arranged after the grinding process has been performed for a predetermined time. The data on the "second position" is stored in the data storage unit 407.

[0170] The difference calculation unit 403 is configured to calculate the difference between the "first position" and the "second position" based on the "first position" and the "second position" stored in the data storage unit 407. The difference between the "first position" and the "second position" is equivalent to the grinding amount of the tool edge. That is, the difference calculation unit 403 calculates the grinding amount of the tool edge by calculating the difference between the "first position" and the "second position". Data on the difference between the "first position" and the "second position" corresponding to the grinding amount is stored in the data storage unit 407.

[0171] For example, the comparison unit 404 is configured to compare the difference between the "first position" and the "second position" stored in the data storage unit 407 with the grinding amount setting value stored in the data storage unit 407. In other words, the comparison unit 404 is configured to compare the grinding amount after the grinding process is performed for a predetermined time with the grinding amount setting value to determine whether the grinding amount after the grinding process is performed for a predetermined time is greater than the grinding amount setting value or less than the grinding amount setting value. And the comparison result of the comparison unit 404 is stored in the data storage unit 407.

[0172] The judgment unit 405 is configured to judge whether to end the grinding process based on the comparison result of the comparison unit 404. For example, when the comparison result of the comparison unit 404 is "the grinding amount after the grinding process is performed for a predetermined time ≥ the grinding amount setting value", it means that the grinding process has been fully performed. In this case, the judgment unit 405 performs a process of displaying that the grinding process has been completed on the display unit 406. As a result, the display unit 406 displays that the grinding process has been completed, and the worker who sees the display presses the stop button, the motor stops and the grinding process is completed. On the other hand, when the comparison result of the comparison unit 404 is "the grinding amount after the grinding process is performed for a predetermined time < the grinding amount setting value", the judgment unit 405 is configured to determine that the grinding process is insufficient and continue the grinding process. In addition, the judgment unit 405 is configured to also manage the grinding time by the timer. For example, even if the grinding process is insufficient, if the preset setting time has passed, a process is performed to display the meaning of forcibly ending the grinding process.

[0173] The grinding control unit 74 is configured as described above.

[0174] <<Control action (control method) of grinding process>>

[0175] Fig.14 This is a flowchart showing the flow of the control operation of the grinding process.

[0176] exist Fig.14 In the above process, first, as a premise, a preset grinding amount setting value is stored in the data storage unit 407. In addition, a preset setting time is stored in the data storage unit 407.

[0177] Before the operation of cutting the resin into particles is performed, the grinding control unit 74 prepares for grinding each of the plurality of blades ( S301 ). Specifically, for example, the motor is started.

[0178] Next, the grinding control unit 74 implements the sliding action of the tool blade (grinding action of the rotating shaft) (S302). Thereafter, the control unit 70 applies the rotating shaft forward force Ff to the rotating shaft 52 (S303) based on the output from the forward and backward movement control position sensor 200B (which is used to control the forward and backward movement of the rotating shaft 52 installed on the tool head 51 equipped with a plurality of tool blades). It should be noted that when the tool head 51 is not in contact with the mold 50 (S304), after the setting of increasing the magnitude of the rotating shaft forward force Ff is performed (S305), the application of the rotating shaft forward force Ff to the rotating shaft 52 is stopped (S306), and the process returns to S302.

[0179] The control unit 70 performs the following control: when the tool head 51 reaches the vicinity of the contact with the mold 50, the output of the forward and backward movement control position sensor 200B is switched to the output of the wear amount detection position sensor 200A, and the rotation axis forward force Ff is applied to the rotation axis 52 according to the output of the wear amount detection position sensor 200A. Here, the output from the wear amount detection position sensor 200A is input to the input unit 400 of the grinding control unit 74, and then the input output data (output signal) of the wear amount detection position sensor 200A is stored in the data storage unit 407.

[0180] Subsequently, when the tool head 51 contacts the mold 50 (S304), the first position acquisition unit 401 acquires the “first position” of the tool head 51 (S307) based on the output data of the wear amount detection position sensor 200A stored in the data storage unit 407. The acquired “first position” of the tool head 51 is stored in the data storage unit 407.

[0181] After that, the grinding process is performed in the resin cutting device 2 (S308). Thus, the grinding of the plurality of tool edges arranged in the tool head 51 is performed. Thereafter, the output from the wear amount detection position sensor 200A is input to the input unit 400 of the grinding control unit 74, and then the input output data of the wear amount detection position sensor 200A is stored in the data storage unit 407. Then, the second position acquisition unit 402 acquires the "second position" of the tool head 51 based on the output data of the wear amount detection position sensor 200A stored in the data storage unit 407 (S309). The acquired "second position" of the tool head 51 is stored in the data storage unit 407.

[0182] Next, the difference calculation unit 403 inputs the "first position" and the "second position" stored in the data storage unit 407, and then calculates the difference between the "first position" and the "second position" (S310). This difference is equivalent to the grinding amount of the tool edge in the grinding process. The difference between the "first position" and the "second position" equivalent to the grinding amount is stored in the data storage unit 407.

[0183] Next, the comparison unit 404 inputs the actual grinding amount and the grinding amount setting value stored in the data storage unit 407, and then compares the actual grinding amount and the grinding amount setting value (S311). Then, the judgment unit 405 judges whether to end the grinding process (S311) based on the comparison result of the comparison unit 404. Specifically, when the comparison result of the comparison unit 404 is "grinding amount ≥ grinding amount setting value", the judgment unit 405 judges that the grinding process has been fully implemented and ends the grinding process (S313). On the other hand, when the comparison result of the comparison unit 404 is "grinding amount < grinding amount setting value", the judgment unit 405 judges whether a preset time set in advance has passed (S312). If the judgment unit 405 judges that the set time has passed, even if the comparison result of the comparison unit 404 is "grinding amount < grinding amount setting value", the grinding process is forced to end. In contrast, if the judgment unit 405 judges that the set time has passed, the grinding control unit 74 determines that the grinding amount of the tool edge is insufficient, and returns to S308 and continues the grinding process. As described above, according to the control operation of the grinding process, the automation of the grinding process can be achieved using the wear amount detection position sensor 200A having a higher position detection accuracy than the forward and backward movement control position sensor 200B.

[0184] <<Effects in the application example>>

[0185] The resin cutting device in the application example is not only provided with a position sensor for forward and backward movement control, but also provided with a position sensor for wear detection having a higher position detection accuracy than that of the position sensor for forward and backward movement control. In addition, the resin cutting device in the application example is provided with a grinding control unit, which is used to determine the appropriate end time of the grinding process based on the output from the position sensor for wear detection. Therefore, according to the application example, the accurate grinding amount of the tool blade can be calculated based on the output from the position sensor for wear detection having a high position detection accuracy, and the grinding control unit can automatically determine the appropriate end time of the grinding process based on the calculated accurate grinding amount. Therefore, according to the application example, the tool blade can be ground (grinded) with an appropriate grinding amount without being affected by the worker's skill level and experience.

[0186] In addition, according to the application example, the following effects can be obtained.

[0187] (1) Since not only the grinding process but also the preparatory process for the grinding process can be automated, it can be expected that labor saving in the preparatory process can be achieved.

[0188] (2) Since the grinding process is automated, even the destination (customer) of the resin cutting device (granulator) can easily perform the grinding work independently.

[0189] (3) Since the tool edge can be properly ground through the automated grinding process, the service life of the tool edge can be extended.

[0190] (4) Since the grinding process is appropriately automated, the quality of pellets produced by the resin cutting device can be improved.

[0191] (5) Since the grinding process is automated, the workload of the grinding work can be reduced and the occurrence of faults during the grinding work can be reduced.

[0192] Although the invention made by the inventors has been specifically described based on the embodiments of the present invention, the present invention is not limited to the above-mentioned embodiments, and it is needless to say that various changes can be made within the scope not departing from the gist thereof.

[0193] Description of Reference Numerals

[0194] 1 Extruder

[0195] 2 Resin cutting device

[0196] 3 Slurry

[0197] 4 piping

[0198] 5 Pumps

[0199] 6. Dehydrator

[0200] 7 Container

[0201] 8 Centrifugal dehydration dryer

[0202] 9 Vibrating screen

[0203] 30 pcs

[0204] 50 Mould

[0205] 50a Nozzle

[0206] 51 Tool head

[0207] 51a Knife edge

[0208] 52 Rotation axis

[0209] 53 Motor

[0210] 54 Sleeve

[0211] 55 Housing

[0212] 60 Flow chamber

[0213] 60a inlet

[0214] 60b Outlet

[0215] 70 Control Department

[0216] 71 Speed ​​control unit

[0217] 72 Rotating axis forward force control unit

[0218] 73 Rotating axis backward force control unit

[0219] 74 Grinding Control Department

[0220] 80 Rotating axis forward force generating unit

[0221] 90 Rotation axis backward force generating part

[0222] 100 Granulation system

[0223] 200A wear detection position sensor

[0224] 200B Position sensor for forward and backward movement control

[0225] 201 test board

[0226] 300 Input

[0227] 301 First position acquisition unit

[0228] 302 Second position acquisition unit

[0229] 303 Difference Calculation Department

[0230] 304 Comparison Department

[0231] 305 Rotating shaft retreat force setting unit

[0232] 306 Data Storage Department

[0233] 400 Input

[0234] 401 First location acquisition unit

[0235] 402 Second location acquisition unit

[0236] 403 Difference Calculation Department

[0237] 404 Comparison Department

[0238] 405 Judgment Department

[0239] 406 Display

[0240] 407 Data storage unit.

Claims

1. A method for controlling a resin cutting device, wherein the resin cutting device produces pellets by cutting a resin discharged from an extruder with a plurality of cutter blades, the method comprising: a step of controlling a cutting blade pressing force of pressing the plurality of cutter blades to a die provided on a resin discharge side of the extruder, the step of controlling the cutting blade pressing force comprising: a wear amount detecting step of detecting the wear amount of the plurality of blades during operation of the resin cutting device to cut the resin into the pellets; and The rotary shaft retraction force control step controls the magnitude of the rotary shaft retraction force applied to a rotary shaft mounted on a tool head provided with the plurality of tool blades, based on the wear amount of the plurality of tool blades detected by the wear amount detection step.

2. The control method of the resin cutting device according to claim 1, wherein: The wear amount detection step detects the wear amounts of the plurality of tool edges based on output from a wear amount detection position sensor.

3. The control method of the resin cutting device according to claim 2, wherein: The resin cutting device is provided with a forward and backward movement control position sensor for controlling the forward and backward movement of the rotating shaft.

4. The control method of the resin cutting device according to claim 3, wherein: The position detection accuracy of the wear amount detection position sensor is higher than the position detection accuracy of the front-rear movement control position sensor.

5. The control method of the resin cutting device according to claim 4, wherein: The process of controlling the pressing force of the tool edge includes: (a) step of bringing the plurality of tool edges into contact with the die based on an output from the forward and backward movement control position sensor and an output from the wear amount detection position sensor; (b) a step of obtaining a first position of the tool head based on an output from the wear amount detection position sensor after the step (a); (c) a step of, after the step (b), performing the operation of the resin cutting device for cutting the resin into the particles for a predetermined time; (d) a step of obtaining a second position of the tool head based on an output from the wear amount detection position sensor after the step (c); (e) step, after the step (d), calculating a difference between the first position and the second position; (f) step, after the step (e), comparing the difference with a preset value; and (g) step, after the step (f), controlling the magnitude of the rotating shaft retracting force applied to the rotating shaft based on a comparison result between the difference and the set value.

6. The control method of the resin cutting device according to claim 5, wherein: In the step (g), when the difference is larger than the set value, control is performed so that the magnitude of the rotating shaft retracting force applied to the rotating shaft increases.

7. The control method of the resin cutting device according to claim 5, wherein: In the step (g), when the difference is smaller than the set value, control is performed so that the magnitude of the rotating shaft retracting force applied to the rotating shaft is reduced.

8. A method for controlling a resin cutting device, wherein the resin cutting device produces pellets by cutting a resin discharged from an extruder with a plurality of blades, the method comprising: before performing an action of cutting the resin into the pellets, performing a grinding process on the plurality of blades respectively, the grinding process comprising: (a) step of bringing the plurality of cutter blades into contact with a die disposed on a resin discharge side of the extruder based on an output from a position sensor for controlling forward and backward movement and an output from a position sensor for detecting wear, wherein: The forward and backward movement control position sensor is used to control the forward and backward movement of the rotating shaft installed on the tool head equipped with the plurality of tool blades; (b) a step of obtaining a first position of the tool head based on an output from the wear amount detection position sensor after the step (a); (c) step of performing the grinding process for a predetermined time after the step (b); (d) a step of obtaining a second position of the tool head based on an output from the wear amount detection position sensor after the step (c); (e) step, after the step (d), calculating a difference between the first position and the second position; as well as (f) step, after the step (e), comparing the difference with a preset value to determine whether to end the grinding process.

9. The control method of the resin cutting device according to claim 8, wherein: The position detection accuracy of the wear amount detection position sensor is higher than the position detection accuracy of the front-rear movement control position sensor.

10. The control method of the resin cutting device according to claim 8, wherein: In the step (f), even when it is determined that the grinding process is to be continued, the grinding process is forcibly terminated when a preset time has elapsed.

11. A resin cutting device comprising: A die disposed on the resin discharge side of the extruder; A plurality of nozzles disposed on the mold; a plurality of cutter blades for cutting the resin discharged from the plurality of nozzles into particles; a tool head provided with the plurality of tool edges; A rotating shaft mounted on the tool head; a motor for rotating the rotating shaft; a flow path chamber constituting a flow path space connected to the tool head; allowing a fluid to flow into an inlet of the flow path chamber; an outlet for allowing the fluid and the particles to flow out of the flow path chamber; a control unit that controls a tool blade pressing force for pressing the plurality of tool blades to the mold; A rotating shaft forward force generating unit, which enables the rotating shaft to generate a rotating shaft forward force; A rotating shaft retreat force generating unit causes the rotating shaft to generate a rotating shaft retreat force; A position sensor for controlling forward and backward movement, used for controlling the forward and backward movement of the rotating shaft; as well as a wear detection position sensor for detecting the wear of the plurality of tool edges, The control unit controls the magnitude of the rotating shaft retracting force applied to the rotating shaft based on an output from the wear amount detecting position sensor.

12. The resin cutting device according to claim 11, wherein: The position detection accuracy of the wear amount detection position sensor is higher than the position detection accuracy of the front-rear movement control position sensor.

13. The resin cutting device according to claim 11, wherein: The control unit has: a first position acquisition unit that acquires a first position of the tool head based on an output from the wear amount detection position sensor; a second position acquisition unit that acquires a second position of the tool head after the resin cutting device has been operating for a predetermined time based on an output from the wear amount detection position sensor; a difference calculation unit configured to calculate a difference between the first position and the second position; a comparing unit configured to compare the difference with a preset setting value; as well as a rotation axis retreat force setting unit, which sets the magnitude of the rotation axis retreat force according to a comparison result between the difference and the set value, The control unit controls the rotating axis retreat force applied to the rotating axis according to the magnitude of the rotating axis retreat force set by the rotating axis retreat force setting unit.

14. A resin cutting device comprising: A die disposed on the resin discharge side of the extruder; A plurality of nozzles disposed on the mold; a plurality of cutter blades for cutting the resin discharged from the plurality of nozzles into particles; a tool head provided with the plurality of tool blades; A rotating shaft mounted on the tool head; a motor for rotating the rotating shaft; a flow path chamber constituting a flow path space connected to the tool head; allowing a fluid to flow into an inlet of the flow path chamber; an outlet for allowing the fluid and the particles to flow out of the flow path chamber; a control unit that controls a tool blade pressing force for pressing the plurality of tool blades to the mold; A rotating shaft forward force generating unit, which enables the rotating shaft to generate a rotating shaft forward force; A rotating shaft retreat force generating unit causes the rotating shaft to generate a rotating shaft retreat force; a forward and backward movement control position sensor, used to control the forward and backward movement of the rotating shaft; and a wear detection position sensor for detecting the wear of the plurality of tool edges, The control unit includes a grinding control unit that controls grinding processing to be performed on each of the plurality of blades before the operation of cutting the resin into the particles is performed. The grinding control unit has: a first position acquisition unit that acquires a first position of the tool head based on an output from the wear amount detection position sensor; a second position acquisition unit that acquires a second position of the tool head after the grinding process is performed for a predetermined time based on an output from the wear amount detection position sensor; a difference calculating unit, which calculates a difference between the first position and the second position; a comparing unit, which compares the difference with a preset setting value; as well as The determination unit determines whether to terminate the grinding process based on a comparison result between the difference and the set value.

15. The resin cutting device according to claim 14, wherein: The position detection accuracy of the wear amount detection position sensor is higher than the position detection accuracy of the front-rear movement control position sensor.

16. A pelletizer comprising an extruder and a resin cutting device for cutting a resin extruded from the extruder into pellets, the resin cutting device comprising: a die disposed on the resin discharge side of the extruder; A plurality of nozzles disposed on the mold; a plurality of cutter blades for cutting the resin discharged from the plurality of nozzles into particles; a tool head provided with the plurality of tool edges; A rotating shaft mounted on the tool head; a motor for rotating the rotating shaft; a flow path chamber constituting a flow path space connected to the tool head; allowing a fluid to flow into an inlet of the flow path chamber; an outlet for allowing the fluid and the particles to flow out of the flow path chamber; a control unit that controls a tool blade pressing force for pressing the plurality of tool blades to the mold; A rotating shaft forward force generating unit, which enables the rotating shaft to generate a rotating shaft forward force; A rotating shaft retreat force generating unit causes the rotating shaft to generate a rotating shaft retreat force; A position sensor for controlling forward and backward movement, used for controlling the forward and backward movement of the rotating shaft; as well as a wear detection position sensor for detecting the wear of the plurality of tool edges, The control unit controls the magnitude of the rotating shaft retracting force applied to the rotating shaft based on an output from the wear amount detecting position sensor.

17. The granulator according to claim 16, wherein The position detection accuracy of the wear amount detection position sensor is higher than the position detection accuracy of the front-rear movement control position sensor.

18. The granulator according to claim 11, wherein The control unit has: a first position acquisition unit that acquires a first position of the tool head based on an output from the wear amount detection position sensor; a second position acquisition unit that acquires a second position of the tool head after the resin cutting device has been operating for a predetermined time based on an output from the wear amount detection position sensor; a difference calculation unit configured to calculate a difference between the first position and the second position; a comparing unit configured to compare the difference with a preset setting value; as well as a rotation axis retreat force setting unit, which sets the magnitude of the rotation axis retreat force according to a comparison result between the difference and the set value, The control unit controls the rotating axis retreat force applied to the rotating axis according to the magnitude of the rotating axis retreat force set by the rotating axis retreat force setting unit.

19. A pelletizer comprising an extruder and a resin cutting device for cutting a resin extruded from the extruder into pellets, the resin cutting device comprising: a die disposed on the resin discharge side of the extruder; A plurality of nozzles disposed on the mold; a plurality of cutter blades for cutting the resin discharged from the plurality of nozzles into particles; a tool head provided with the plurality of tool edges; A rotating shaft mounted on the tool head; a motor for rotating the rotating shaft; a flow path chamber constituting a flow path space connected to the tool head; allowing a fluid to flow into an inlet of the flow path chamber; an outlet for allowing the fluid and the particles to flow out of the flow path chamber; a control unit that controls a tool blade pressing force for pressing the plurality of tool blades to the mold; A rotating shaft forward force generating unit, which enables the rotating shaft to generate a rotating shaft forward force; A rotating shaft retreat force generating unit causes the rotating shaft to generate a rotating shaft retreat force; a forward and backward movement control position sensor, used to control the forward and backward movement of the rotating shaft; and a wear detection position sensor for detecting the wear of the plurality of tool edges, The control unit includes a grinding control unit that controls grinding processing performed on each of the plurality of blades before the operation of cutting the resin into the particles is performed, and the grinding control unit has: a first position acquisition unit that acquires a first position of the tool head based on an output from the wear amount detection position sensor; a second position acquisition unit that acquires a second position of the tool head after the grinding process is performed for a predetermined time based on an output from the wear amount detection position sensor; a difference calculating unit, which calculates a difference between the first position and the second position; a comparing unit, which compares the difference with a preset setting value; as well as The determination unit determines whether to terminate the grinding process based on a comparison result between the difference and the set value.

20. The granulator according to claim 19, wherein The position detection accuracy of the wear amount detection position sensor is higher than the position detection accuracy of the front-rear movement control position sensor.

Images