INJECTION METHOD OF INJECTION MEDIUM AND INJECTION SYSTEM OF INJECTION MEDIUM

Abstract

According to one aspect of the present disclosure, an injection method of an injection medium is provided. The injection method of the injection medium is an injection method of injecting the injection medium to a workpiece with gas. The injection method comprises: acquiring an injection state of the injection medium with respect to the workpiece; and injecting intermittently the injection medium to the workpiece while controlling supplying of the gas on a basis of the injection state of the injection medium.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2022-158722 filed on Sep. 30, 2022, and the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an injection method of an injection medium and an injection system of the injection medium.

BACKGROUND

An apparatus that performs surface treatment of a workpiece (treatment target object) by injecting abrasive particles (injection media) to the workpiece has hitherto been known. For example, in Japanese Unexamined Patent Publication No. 2004-154894, a sandblasting apparatus that injects a mixed fluid of high-pressure gas and abrasive particles is described. The apparatus includes an injection nozzle to which the high-pressure gas and the abrasive particles are supplied and which continuously injects the abrasive particles.

SUMMARY

In the sandblasting apparatus described in Japanese Unexamined Patent Publication No. 2004-154894, there is a fear that the supply amount of gas may increase in accordance with the amount of injection time and the electricity consumption in a supply source that supplies gas may increase. The present disclosure provides an injection method of an injection medium and an injection system of the injection medium that suppress the increase of the supply amount of gas used in the injection of the injection medium.

An injection method of an injection medium according to the present disclosure is a method of injecting the injection medium to a workpiece with gas and includes steps of (1) and (2).

• • (1) Acquiring an injection state of the injection medium with respect to the workpiece.
  • (2) Injecting intermittently the injection medium to the workpiece while controlling supplying of the gas on a basis of the injection state of the injection medium.

An injection system of an injection medium according to another aspect of the present disclosure includes an injection apparatus, a measuring apparatus, and a control apparatus. The injection apparatus is configured to inject the injection medium to the workpiece with gas. The measuring apparatus is configured to measure an injection state with respect to the workpiece by the injection apparatus. The control apparatus is configured to control the injection apparatus. The control apparatus includes an acquisition unit and an injection control unit. The acquisition unit is configured to acquire the injection state with respect to the workpiece from the measuring apparatus. The injection control unit is configured to control the injection apparatus such that the injection apparatus intermittently injects the injection medium to the workpiece and configured to control supplying of the gas on a basis of the injection state of the injection medium.

According to the present disclosure, the increase of the supply amount of the gas used in the injection of the injection medium can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view schematically showing an injection system according to one embodiment;

FIG. 2 is a block diagram showing a functional configuration of the injection system of an injection medium according to one embodiment;

FIG. 3 is a flowchart showing the injection method of the injection medium according to one embodiment;

FIG. 4 is a graph showing one example of a relationship between the residual stress and the depth of a workpiece;

FIG. 5 is a graph showing one example of a relationship between the AE parameter and the amount of time;

FIG. 6 is a graph showing one example of a relationship between the pressure of gas and the amount of time; and

FIG. 7 is a graph showing one example of a relationship between the flow rate of the gas and the amount of time.

DETAILED DESCRIPTION

Overview of Embodiment of Present Disclosure

First, an overview of an embodiment of the present disclosure is described.

(Clause 1) An injection method of an injection medium according to one aspect of the present disclosure is a method of injecting the injection medium to a workpiece with gas, and includes: acquiring an injection state of the injection medium with respect to the workpiece; and injecting intermittently the injection medium to the workpiece while controlling supplying of the gas on a basis of the injection state of the injection medium.

In the injection method of the injection medium, the supplying of the gas is controlled on the basis of the injection state of the injection medium, and the injection medium is intermittently injected to the workpiece with gas. The injection method of the injection medium can decrease the amount of the injection medium that is not contributing to the surface treatment on the workpiece while appropriately securing the amount of the injection medium contributing to the surface treatment on the workpiece by appropriately controlling the supplying of the gas on the basis of the injection state of the injection medium. As a result, the injection method of the injection medium can appropriately apply the surface treatment to the workpiece as with a case where the injection medium is continuously injected, for example. By controlling the injection state of the injection medium, it can be monitored whether the surface treatment has been able to be appropriately applied to the workpiece, and the certainty of the processing of the workpiece can be checked. The injection method of the injection medium can provide an amount of time by which the injection medium is not injected as compared to when the injection medium is continuously injected by intermittently injecting the injection medium. Therefore, the injection method of the injection medium can suppress the supply amount of the gas used in the injection of the injection medium.

(Clause 2) In the injection method of the injection medium according to Clause 1, the injecting includes intermittently injecting the injection medium to the workpiece while adjusting at least one of a flow rate and a pressure of the gas to be supplied on a basis of the injection state of the injection medium. In this case, in the injection method of the injection medium, the injection medium is injected with an appropriate output on the basis of at least one of the adjusted flow rate and pressure. In the injection method of the injection medium, even when the supply amount of the gas is decreased and the injecting amount of the injection medium is decreased as compared to when the injection medium is continuously injected, the surface treatment of the workpiece is performed by the injection medium injected with an appropriate output. As a result, the injection method of the injection medium can appropriately apply the surface treatment to the workpiece as with a case where the injection medium is continuously injected, for example. The injection method of the injection medium can appropriately apply the surface treatment to the workpiece with a small supply amount of gas even when the amount of time is similar to that when the injection medium is continuously injected.

(Clause 3) In the injection method of the injection medium according to Clause 1 or 2, the acquiring further acquires a residual stress value requested for the workpiece; and the injecting includes intermittently injecting the injection medium to the workpiece while adjusting an injection time interval in injection of the injection medium per time on a basis of the injection state of the injection medium and the residual stress value. In this case, the injection method of the injection medium can intermittently inject the injection medium at an appropriate time interval, efficiently apply the surface treatment to the workpiece, and appropriately obtain the workpiece to which the residual stress corresponding to the requested residual stress value has been applied.

(Clause 4) The injection method of the injection medium according to any one of Clauses 1 to 3, the acquiring further acquires front surface information relating to a front surface state requested for the workpiece, and the injecting includes intermittently injecting the injection medium to the workpiece while adjusting an injection time interval in injection of the injection medium per time on a basis of the injection state of the injection medium and the front surface information. In this case, the injection method of the injection medium can intermittently inject the injection medium at an appropriate time interval, efficiently apply the surface treatment to the workpiece, and appropriately obtain the workpiece corresponding to the requested front surface state.

(Clause 5) A injection system of an injection medium according to another aspect of the present disclosure comprises: an injection apparatus configured to inject the injection medium to a workpiece with gas; a measuring apparatus configured to measure an injection state of the injection medium with respect to the workpiece by the injection apparatus; and a control apparatus configured to control the injection apparatus. The control apparatus includes: an acquisition unit configured to acquire the injection state of the injection medium from the measuring apparatus; and an injection control unit configured to control the injection apparatus such that the injection apparatus intermittently injects the injection medium to the workpiece and configured to control supplying of the gas on a basis of the injection state of the injection medium. In the injection system of the injection medium, the same effect as that of the injection method of the injection medium according to Clause 1 is exhibited.

Exemplification of Embodiment of Present Disclosure

The embodiment of the present disclosure is described below with reference to the drawings. In the description below, the same or equivalent elements are denoted by the same reference characters, and overlapping description is not repeated. The dimension ratio in the drawings does not necessarily match with the dimension ratio in the description.

[Overview of Injection System]

FIG. 1 is a view schematically showing an injection system of an injection medium according to one embodiment. An injection system 1 of an injection medium S (hereinafter may be simply referred to as the “injection system 1”) shown in FIG. 1 injects (sprays) an injection medium to a workpiece with gas in order to process a workpiece W (treatment target object). In this embodiment, treatment of injecting the injection medium S in the injection system 1 is referred to as “injection treatment”. The injection treatment includes shot blasting processing of which purpose is descaling, deburring, surface roughness adjustment, and the like, and shot peening treatment of which purpose is to apply residual compressive stress to the workpiece. As one example, the injection treatment of this embodiment means shot peening treatment.

As shown in FIG. 1, the injection system 1 includes an injection apparatus 10, a measuring apparatus 20 (sensing unit), and a control apparatus 30. The injection apparatus 10 injects the injection medium S to the workpiece W with gas. The injection apparatus 10 processes a front surface of the workpiece W by injecting the injection medium S to the workpiece W and causing the injection medium S to collide with the workpiece W. For example, the injection apparatus 10 is a shot peening apparatus that applies compressive residual stress to a front surface of the workpiece W. Examples of the workpiece W on which the injection treatment is performed by the injection apparatus 10 are automobile parts such as a cylinder head and a crankshaft, a gear, and a die, but the workpiece W is not limited to the above. When the compressive residual stress is applied to the front surface of the workpiece W by the injection treatment, fatigue characteristics of the workpiece W improve.

The injection apparatus 10 is a gravity (suction) shot peening apparatus. The injection apparatus 10 may be a direct-pressure shot peening apparatus. Steel balls are used as the injection medium S injected to the workpiece W, for example. The particle size of the steel ball is selected, as appropriate, in accordance with the compressive residual stress required for (to be applied to) the workpiece W.

The injection apparatus 10 includes an injection medium tank 11, a compressor 12, and a nozzle 15. The injection medium tank 11 stores therein the injection medium S. The injection medium tank 11 is connected to the nozzle 15 via a pipe 60. In the injection medium tank 11, an outflow port 11A that causes the injection medium S to flow out is provided. An openable and closeable cut gate 61 is provided on the outflow port 11A. The pipe 60 is connected to the outflow port 11A via the cut gate 61. An adjustment valve that adjusts the amount of the injection medium S injected from the nozzle 15 may be provided in the pipe 60.

The compressor 12 generates compressed gas (compressed air) and supplies the compressed gas to the nozzle 15. The compressor 12 is connected to the nozzle 15 via a pipe 62. An air filter 63 is provided in a position between the nozzle 15 and the compressor 12 in the pipe 62. The air filter 63 removes dust from the compressed gas supplied to the nozzle 15 from the compressor 12. A regulator 64 is provided in a position between the nozzle 15 and the air filter 63 in the pipe 62. The regulator 64 is a valve that reduces the pressure of the compressed gas supplied from the compressor 12 to the nozzle 15 to a predetermined pressure.

A first pressure sensor 65 is provided in a position between the nozzle 15 and the regulator 64 in the pipe 62. The first pressure sensor 65 measures the pressure of the compressed gas of which pressure has been adjusted by the regulator 64. A solenoid valve 66 is provided in a position between the nozzle 15 and the first pressure sensor 65 in the pipe 62. The solenoid valve 66 controls passage or stoppage of the compressed gas supplied from the compressor 12 to the nozzle 15. A flow rate sensor 67 is provided in a position between the nozzle 15 and the solenoid valve 66 in the pipe 62. The flow rate sensor 67 measures the flow rate of the compressed gas supplied from the compressor 12 to the nozzle 15. A second pressure sensor 68 is provided in a position between the nozzle 15 and the flow rate sensor 67 in the pipe 62. The second pressure sensor 68 measures the pressure of the compressed gas that has passed through the solenoid valve 66 (flow rate sensor 67).

The injection apparatus 10 has an intermittent injection unit 69 in a position between the nozzle 15 and the second pressure sensor 68 in the pipe 62. The intermittent injection unit 69 is provided on the upstream side (compressor 12 side) of a mixing portion 15A described below. The intermittent injection unit 69 performs intermittent injection of the compressed gas supplied from the compressor 12. The intermittent injection unit 69 is electrically or mechanically controlled. The intermittent injection unit 69 of this embodiment has a valve that is electrically controlled, for example. The intermittent injection unit 69 adjusts the flow rate of the compressed gas supplied to the nozzle 15 to a predetermined flow rate.

As above, the first pressure sensor 65, the flow rate sensor 67, and the second pressure sensor 68 are provided on the upstream side (compressor 12 side) of the nozzle 15 (the mixing portion 15A described below) in the pipe 62. The flow rate sensor 67 is provided in a portion close to a source pressure of the gas of which pressure has been adjusted in the pipe 62, and is provided in the vicinity of the regulator 64. The intermittent injection unit 69 is provided on the upstream side (the compressor 12 side) immediately before the nozzle 15 (the mixing portion 15A described below) in the pipe 62, for example. The order of each configuration in the pipe 62 is not limited to the above.

The cut gate 61, the regulator 64, the first pressure sensor 65, the solenoid valve 66, the flow rate sensor 67, the second pressure sensor 68, and the intermittent injection unit 69 in the injection system 1 are communicably connected to the control apparatus 30. The flow rate sensor 67 converts the measured flow rate to digital data and outputs the digital data to the control apparatus 30. The first pressure sensor 65 and the second pressure sensor 68 converts the measured pressure to digital data and outputs the digital data to the control apparatus 30.

The nozzle 15 is provided on distal end portions of the pipe 60 and the pipe 62 and injects the injection medium S supplied from the injection medium tank 11 with the compressed gas as a gas-solid two-phase flow. The inner portion of the nozzle 15 configures the mixing portion 15A in which the injection medium S supplied from the injection medium tank 11 and the compressed gas supplied from the compressor 12 are mixed with each other as a result of the pipe 60 and the pipe 62 connecting to the nozzle 15.

The nozzle 15 is disposed on the inner portion of a cabinet 70. The cabinet 70 defines a processing chamber 70s that is a space for processing the workpiece W. The workpiece W is disposed on a mounting table 71 in the processing chamber 70s. When the injection treatment of the workpiece W is performed, the workpiece W is disposed in the processing chamber 70s, the injection medium S is injected toward the workpiece in the processing chamber 70s from the nozzle 15, and the injection medium S is caused to collide with the workpiece W.

Although not shown in FIG. 1, the injection apparatus 10 may further include a dust collection apparatus, a classification apparatus, and a circulation apparatus for reusing the used injection medium S. The dust collection apparatus is connected to the processing chamber 70s via the classification apparatus and transfers the injection medium S and swarf of the workpiece W that have dropped to a lower portion of the processing chamber 70s to the classification apparatus by sucking the injection medium S and swarf of the workpiece W. The classification apparatus is a cyclone classification apparatus, for example, and receives the injection medium S and the swarf of the workpiece and classifies the injection medium S and the swarf of the workpiece into powder reusable as the injection medium S and powder that cannot be used as the injection medium S. The circulation apparatus returns the usable injection medium S to the injection medium tank 11 via a packet elevator, a screw conveyor, a separator, and the like.

The measuring apparatus 20 detects the injection state of the injection medium S in the injection apparatus 10. FIG. 2 is a block diagram showing a functional configuration of the injection system of the injection medium according to one embodiment. As shown in FIG. 1 and FIG. 2, the measuring apparatus 20 includes a sensor 21, an AD conversion unit 22, and a communication unit 23. The sensor 21 acquires a feature amount indicating the injection state of the injection medium S. The sensor 21 of this embodiment is an AE sensor, for example. The sensor 21 is fixed to the nozzle 15, measures an acoustic emission (AE) that is generated when the injection medium S is injected from the nozzle 15 of the injection apparatus 10, and outputs a signal waveform (hereinafter referred to as an “AE signal waveform”) relating to the measured AE. The AE signal waveform is a signal waveform relating to elastic waves such as sound waves or vibration generated when the injection medium S passes (injected) through the nozzle 15. In the AE signal waveform, as characteristic parameters relating to the intensity of the injection treatment, the amplitude, the duration, the AE count, the rise time, the AE count rate, and the average frequency, for example, are included.

The AD conversion unit 22 converts the AE signal waveform output from the sensor 21 to digital data and outputs the digital data. The communication unit 23 is a communication module that can perform wireless communication such as an LAN, Bluetooth®, and Wifi. The communication unit 23 acquires digital data (hereinafter described as signal data) of the AE signal waveform measured by the sensor 21 from the AD conversion unit 22 and transmits the signal data to the control apparatus 30 by wireless communication. The first pressure sensor 65, the flow rate sensor 67, and the second pressure sensor 68 may include an AD conversion unit and a communication unit similar to the AD conversion unit 22 and the communication unit 23 included in the measuring apparatus 20.

The control apparatus 30 controls the entire injection system 1 of the injection medium S. The control apparatus 30 is configured as a programmable logic controller (PLC) as one example. The control apparatus 30 may be configured as a normal computer system including a main storage apparatus such as a central processing unit (CPU), a random access memory (RAM), and a read only memory (ROM), an input device such as a touch screen and a keyboard, an output device such as a display, an auxiliary storage apparatus such has a hard disk, and the like.

On the control apparatus 30, a control panel that can be operated by a worker, for example, is provided. The control apparatus 30 is communicably connected to the injection apparatus 10 and the measuring apparatus 20. The control apparatus 30 outputs control signals to the injection apparatus 10 and the measuring apparatus 20 and controls the operation of each configuration. The control apparatus 30 reads a program prepared in advance and causes the injection apparatus 10 and the measuring apparatus 20 to operate. The control apparatus 30 may cause the injection apparatus 10 and the measuring apparatus 20 to operate in accordance with command operation of the worker accepted by the control panel (not shown). In the control apparatus 30, an operator can perform input operation of a command for managing the injection apparatus 10 and the like with use of the input device. The control apparatus 30 visualizes and displays the operation situation of the injection apparatus 10 by the output device.

In the injection system 1, for example, in order to perform control such that the injection medium S can be intermittently injected to the workpiece W by the injection apparatus 10 in an appropriate manner (such that the residual stress corresponding to a required stress value described below can be appropriately applied to the workpiece W), the injection treatment is performed before processing is performed on the workpiece W, and at least one of the AE parameter, the flow rate, and pressure is measured. The control apparatus 30 of this embodiment regularly controls (adjusts) injection conditions on the basis of the AE parameter. The injection conditions are conditions for an output set for the injection apparatus 10 in order to inject the injection medium S and include a condition for supplying gas, for example. The injection conditions include the flow rate and the pressure of the gas supplied to the nozzle 15 and the amount of injection time and the injection time interval of the injection medium S, for example. The control is performed once or a plurality of times before the injection treatment is performed on the workpiece W, for example. The control apparatus 30 controls the injection apparatus 10 so as to inject the injection medium S by the controlled (adjusted) injection conditions. The control apparatus 30 is communicably connected to the intermittent injection unit 69 in the injection apparatus 10 and outputs a control signal so as to intermittently supply the gas to the nozzle 15 in accordance with a program or command operation. Description is made in detail below.

As shown in FIG. 2, the control apparatus 30 includes an acquisition unit 31, an injection control unit 32, and a storage unit 35 as functional components. The acquisition unit 31 acquires the injection state of the injection medium S by the injection apparatus 10 from the measuring apparatus 20. The acquisition unit 31 acquires signal data transmitted from the communication unit 23 of the measuring apparatus 20 as one example of the injection state of the injection medium S by the injection apparatus 10. The acquisition unit 31 acquires the flow rate of the gas measured in the flow rate sensor 67, and acquires the pressure of the gas measured in at least one of the first pressure sensor 65 and the second pressure sensor 68.

The acquisition unit 31 acquires processing conditions for the workpiece W that is a target to which the injection medium S is injected in the injection apparatus 10. The acquisition unit 31 may acquire processing conditions input by the operator of the injection apparatus 10 or may acquire processing conditions stored in the storage unit 35 in advance, for example. As described above, the injection medium S injected from the nozzle 15 of the injection apparatus 10 collides with the workpiece W. A beating and stretching force acts on the front surface of the workpiece W by the collision of the injection medium S, and hence a reaction force against the force is generated in the workpiece W. As a result, the residual stress (compressive residual stress) is applied to the workpiece W. The residual stress to be applied to the workpiece W is determined in accordance with the purpose of the workpiece W. In order to apply the requested residual stress to the workpiece W, it is required to perform the injection treatment on the workpiece W with an appropriate strength and at an appropriate time interval. The acquisition unit 31 acquires a required stress value (one example of a residual stress value) that is the residual stress requested for the workpiece W that is a target to which the injection medium S is injected in the injection apparatus 10 as the processing condition. The required stress value is a peak depth and/or a peak value of the compressive residual stress, the surface residual stress, and an integrated value in a residual stress distribution indicated by the residual stress and the depth, for example. The acquisition unit 31 may acquire the amount of injection time of the injection medium S described below, the injection time interval of the injection medium S described below, and information (the particle size, the hardness, and the like) relating to the injection medium S as the processing conditions. A case where the injection medium S is intermittently injected on the workpiece W by predetermined flow rate and pressure of the gas in order to obtain the required stress value in the workpiece W is expressed as “intermittent injection” below. A case where the injection medium S is continuously injected on the workpiece W by predetermined flow rate and pressure of the gas in order to obtain the required stress value in the workpiece W is expressed as “continuous injection” below.

The injection control unit 32 controls the supplying of the gas on the basis of the injection state of the injection medium S and controls the injection apparatus 10 such that the injection apparatus 10 intermittently injects the injection medium S to the workpiece W. The injection control unit 32 has a controller 33 and an intermittent injection control unit 34. The controller 33 controls the supplying of the gas on the basis of the injection state of the injection medium S with respect to the workpiece W. The control of the supplying of the gas includes setting and adjusting at least one of the flow rate and the pressure of the gas supplied by the injection control unit 32 after the measuring apparatus 20 detects the feature amount according to the supplying of the gas including at least one of the AE parameter, the flow rate, and the pressure. The control of the supplying of the gas also includes performing, after the measuring apparatus 20 detects the feature amount described above, control such that the injection control unit 32 supplies gas while maintaining the flow rate and pressure before the detection. The control of the supplying of the gas may include predicting and determining by the injection control unit 32 whether appropriate injection is performed in the injection apparatus 10 after the measuring apparatus 20 detects the feature amount described above. The controller 33 of this embodiment controls the flow rate and the pressure of the gas for obtaining the required stress value in the workpiece W on the basis of the processing conditions of the workpiece W and the AE parameter indicated as the injection state of the injection medium S.

The controller 33 calculates the AE parameter from the AE signal waveform included in the signal data acquired by the acquisition unit 31. As the AE parameter, the amplitude, the duration, the AE count, or the rise time of the AE signal waveform, for example, are used. The peak value, the average value, or the effective value of the AE signal waveform may be used as the AE parameter. A correlation exists between the AE parameter and the value of the residual stress of the workpiece W. From the above, for example, a model formula expressing the correlation between the AE parameter and the value of the residual stress is stored in the storage unit 35 of the control apparatus 30 in advance. The controller 33 calculates a requested AE parameter that is an AE parameter corresponding to the required stress value acquired by the acquisition unit 31 with use of the model formula, for example. The calculation is not limited to the model formula described above, and the requested AE parameter may be calculated by various other methods. For example, the requested AE parameter may be calculated on the basis of a data table indicating the relationship between the AE parameter and the value of the residual stress of the workpiece W and the like.

The controller 33 calculates the flow rate and the pressure of the gas supplied to the nozzle 15 on the basis of the AE parameter calculated from the signal data acquired by the acquisition unit 31 and the requested AE parameter. The controller 33 acquires a data table indicating the relationship between the pressure of the gas to be supplied and the AE parameter and a data table indicating the relationship between the flow rate of the gas to be supplied and the AE parameter stored in the storage unit 35 in advance. The controller 33 extracts the flow rate and the pressure of the gas corresponding to the requested AE parameter with use of those data tables.

The controller 33 calculates a difference between the flow rate of the gas at the time point of acquisition of the signal data and the flow rate of the gas corresponding to the requested AE parameter, and determines the value of the flow rate adjusted (increased or decreased) from the flow rate at the time of calculation of the measured AE parameter. The controller 33 allocates the maximum value of the flow rate of the gas at the time of the continuous injection with which the requested AE parameter (required stress value) can be obtained to the maximum value of the flow rate at the time of the intermittent injection as one example of the flow rate of the gas corresponding to the requested AE parameter.

The controller 33 calculates the difference between the pressure of the gas at the time of acquisition of signal data in at least one of the first pressure sensor 65 and the second pressure sensor 68 and the pressure of the gas corresponding to the requested AE parameter and determines the value of the pressure to be adjusted (increased or decreased). The controller 33 allocates the maximum value of the pressure of the gas at the time of the continuous injection with which the requested AE parameter (required stress value) can be obtained, for example, to the minimum value of the pressure at the time of surface treatment of the workpiece W by intermittent injection as one example of the pressure of the gas corresponding to the requested AE parameter. The minimum value of the pressure is the minimum value from when the treatment of applying residual stress to the workpiece W is started and intermittent supplying of the gas is performed to when the intermittent supplying of the gas ends.

The controller 33 does not necessarily need to calculate each of values of the flow rate and the pressure to be adjusted. The controller 33 may determine the flow rate to be adjusted, to thereby determine the value of the corresponding pressure, for example. The controller 33 may determine the pressure to be adjusted, to thereby determine the value of the corresponding flow rate, for example. The controller 33 may define the values of the flow rate and the pressure to be directly adjusted from the difference between the AE parameter and the requested AE parameter. The controller 33 saves the calculated flow rate and pressure of the gas in the storage unit 35.

The controller 33 sets the amount of injection time of the injection medium S until the predetermined residual stress is applied to the workpiece W, and the injection time interval of the injection medium S. The amount of injection time of the injection medium S may be the amount of supplying time of the gas. The controller 33 sets a required amount of time at the time of the continuous injection as the amount of injection time at the time of the intermittent injection, for example. The injection time interval of the injection medium S may be the supplying time interval of the gas. When the injection apparatus 10 intermittently injects the injection medium S, the injection apparatus 10 repeats an operation of starting the supplying of the gas and stopping the supplying of the gas with respect to the nozzle 15 by a plurality of times within the amount of injection time of the injection medium S. The injection time interval of the injection medium S means the amount of injection time in the injection of the injection medium S per time and specifically means the amount of time from the start of the supplying to the stop of the supplying of the gas per time. The injection time interval is 0.5 seconds, for example. The injection time interval of the injection medium S may be fixed or may be different for each injection of the injection medium S within the amount of injection time of the injection medium S. When the injection apparatus 10 intermittently injects the injection medium S, the injection time interval of the injection medium S necessary until the residual stress that is the same as that in continuous injection is applied to the workpiece W is defined in advance to correspond to at least one of the AE parameter, the flow rate, and pressure. The injection time interval may be set in advance in such a way so as to correspond to each required stress value requested for the workpiece W. The controller 33 acquires a data table indicating the relationship between the injection time interval of the injection medium S and the flow rate or the pressure of the gas to be supplied that is stored in the storage unit 35 in advance, for example. The controller 33 sets the injection time interval corresponding to the calculated flow rate or pressure of the gas with use of the data table, for example.

The intermittent injection control unit 34 controls the injection apparatus 10 such that the injection apparatus 10 intermittently injects the injection medium S to the workpiece W on the basis of the injection conditions controlled by the controller 33. The intermittent injection control unit 34 executes the control of the valve in the intermittent injection unit 69 such that the gas at the flow rate calculated in the controller 33 is supplied to the nozzle 15, for example. The intermittent injection control unit 34 executes the control of the regulator 64 such that the gas at the pressure calculated in the controller 33 is supplied to the nozzle 15, for example. The intermittent injection control unit 34 acquires the pressure of the compressed gas generated from the compressor 12 and decreases the pressure of the gas to the pressure calculated in the controller 33, for example. The intermittent injection control unit 34 adjusts the opening degree of the valve in the intermittent injection unit 69 and opens and closes the valve during the amount of injection time such that the injection time interval set in the controller 33 is obtained. The intermittent injection control unit 34 adjusts the opening degree of the valve in the intermittent injection unit 69 set in the controller 33 and opens and closes the valve.

[Injection Method of Injection Medium]

Next, an injection method of the injection medium S to the workpiece W using the injection system 1 described above is described. FIG. 3 is a flowchart showing the injection method of the injection medium according to one embodiment. The injection method of the injection medium S is executed when the injection apparatus 10 experimentally injects the injection medium S to the workpiece W by a predetermined amount of injection time, for example. In this flowchart, the amount of execution time (amount of injection time) of the injection method of the injection medium S in the injection apparatus 10 is set in advance.

In this method, first, the acquisition unit 31 of the control apparatus 30 acquires the injection state of the injection medium S from the measuring apparatus 20 (Step S1: one example of the acquiring). The acquisition unit 31 acquires the AE parameter from the measuring apparatus 20. The acquisition unit 31 acquires the flow rate of the gas measured in the flow rate sensor 67, and acquires the pressure of the gas measured in at least one of the first pressure sensor 65 and the second pressure sensor 68.

Next, the injection control unit 32 is configured to control the injection apparatus such that the injection apparatus intermittently injects the injection medium S to the workpiece W and configured to control the supplying of the gas on the basis of the injection state of the injection medium S and (Step S3: one example of the injecting). The controller 33 calculates the flow rate and the pressure of the gas supplied to the nozzle 15 and the injection time interval of the injection medium S on the basis of the AE parameter indicating the injection state of the injection medium S and the requested AE parameter. The intermittent injection control unit 34 adjusts the regulator 64 and the intermittent injection unit 69 such that the flow rate, the pressure, and the injection time interval of the injection medium S are obtained.

Next, the intermittent injection control unit 34 determines whether the predetermined amount of injection time has elapsed (Step S5). When the intermittent injection control unit 34 determines that the predetermined amount of injection time has not elapsed, the intermittent injection control unit 34 returns to Step S1 and adjusts the injection conditions of the injection medium S. When the intermittent injection control unit 34 determines that the predetermined amount of injection time has elapsed, the intermittent injection control unit 34 ends the series of treatment of the injection method.

Conclusion of Embodiment

In the injection system 1 and the injection method of the injection medium S of this embodiment, the supplying of the gas is controlled on the basis of the injection state of the injection medium S, and the injection medium S is intermittently injected to the workpiece W with gas. The injection method of the injection medium S can decrease the amount of the injection medium S that is not contributing to the surface treatment on the workpiece W while appropriately securing the amount of the injection medium S contributing to the surface treatment on the workpiece W by appropriately managing the supplying of the gas on the basis of the injection state of the injection medium S. As a result, the injection method of the injection medium S can appropriately apply surface treatment to the workpiece W as with continuous injecting, for example. By managing the injection state of the injection medium S, it can be monitored whether the surface treatment has been able to be appropriately applied to the workpiece W, and the certainty of the processing of the workpiece W can be checked. The injection method of the injection medium S can set the amount of time for not injecting the injection medium S by intermittent injection as compared to continuous injection. Therefore, the injection method of the injection medium S can suppress the supply amount of the gas used in the injection of the injection medium S. As a result, the increase in the amount of electricity usage when the compressed gas is supplied in the compressor 12 can be suppressed, and downsizing of the compressor 12 can also be realized.

The injecting (Step S3) includes intermittently injecting the injection medium to the workpiece W while adjusting at least one of the flow rate and the pressure of the gas to be supplied on the basis of the injection state of the injection medium S. In this case, in the injection method of the injection medium S, the injection medium S is injected with an appropriate output on the basis of at least one of the adjusted flow rate and pressure. In the injection method of the injection medium S, even when the supply amount of the gas is decreased and the injecting amount of the injection medium S is decreased as compared to when the injection medium S is continuously injected, the surface treatment of the workpiece W is performed by the injection medium S injected with an appropriate output. As a result, the injection method of the injection medium S can appropriately apply the surface treatment to the workpiece W as with the continuous injection. For example, the injection method of the injection medium S can appropriately apply the surface treatment to the workpiece W with a small supply amount of gas even when the amount of time is similar to that in the continuous injection. Specifically, by intermittently injection the injection medium S within the same amount of time as the amount of time by which the injection medium S is continuously injected, the flow rate (total amount) of the gas supplied to the nozzle 15 can be suppressed to 20 percent or more and less than 100 percent of the flow rate (total amount) of the gas that is continuously supplied. In the injection method of the injection medium S using the injection system 1 of this embodiment, the injection conditions (the flow rate and the pressure of the gas to be supplied and the like) in the intermittent injection can be caused to correspond to the difference between the total amount of the gas at the time of the continuous injection and the total amount of the gas at the time of the intermittent injection, for example. The injection conditions in the intermittent injection can be caused to correspond to the ratio of integrated value of the residual stress distribution of the workpiece W at the time of the intermittent injection to the integrated value of the residual stress distribution of the workpiece W at the time of the continuous injection, for example. Therefore, in the injection method of the injection medium S using the injection system 1 of this embodiment, by selecting the predetermined injection conditions, the workpiece W having the residual stress similar to that at the time of the continuous injection can be obtained even at the time of the intermittent injection, and the total amount of the gas to be supplied to the nozzle 15 can also be decreased.

The acquiring (Step S1) further acquires a residual stress value requested for the workpiece, and the injecting (Step S3) includes intermittently injecting the injection medium S to the workpiece W while adjusting an injection time interval in injection of the injection medium S per time on the basis of the injection state of the injection medium S and the residual stress value. In this case, the injection method of the injection medium S can intermittently inject the injection medium S at an appropriate time interval, efficiently apply the surface treatment to the workpiece W, and appropriately obtain the workpiece W to which the residual stress corresponding to the requested residual stress value has been applied.

Modified Example

The injection system of the injection medium and the injection method of the injection medium according to various embodiments have been described above. However, the disclosure is not limited to the embodiment described above, and various modified aspects can be configured without changing the gist of the disclosure.

In the embodiment described above, the elastic waves when the injection medium S passes through the nozzle 15 are measured by using the AE sensor as the sensor 21 of the measuring apparatus 20. However, the measuring apparatus 20 may measure a wave motion other than the elastic waves and may output a signal waveform relating to the wave motion. Examples of a sensor that measures the wave motion other than the elastic waves include a vibration sensor, an acceleration sensor, and an impact sensor that measure vibration, an ultrasonic sensor that measures ultrasound waves, an electromagnetic sensor that measures electricity and magnetism, an eddy current sensor, a laser displacement meter, and an ultrasonic sensor that measure displacement, and a color sensor that measures color.

When the AE sensor is used as the sensor 21, the measuring apparatus 20 does not necessarily need to be provided on the nozzle 15. The measuring apparatus 20 may be provided around the workpiece W. For example, the measuring apparatus 20 may be provided on the mounting table 71 of the workpiece W. The measuring apparatus 20 outputs a signal relating to the wave motion generated by the collision of the injection medium S injected to the workpiece W from the injection apparatus 10. The wave motion is a collective term of waves generated when the injection medium S collides with the workpiece W and is a concept including elastic waves, vibration, ultrasound waves, and electromagnetic waves.

The sensor 21 of the measuring apparatus 20 does not necessarily need to be provided in a configuration around the workpiece W and the nozzle 15. The sensor 21 of the measuring apparatus 20 may be replaced by the flow rate sensor 67. At this time, the controller 33 controls the supplying of the gas on the basis of the flow rate of the gas as the injection state of the injection medium S with respect to the workpiece W. In the storage unit 35 of the control apparatus 30, a model formula expressing a correlation between the flow rate of the gas to be supplied to the nozzle 15 and the value of the residual stress is stored in advance. The controller 33 calculates a requested flow rate that is a flow rate corresponding to the required stress value acquired by the acquisition unit 31 with use of the model formula. The controller 33 calculates the flow rate and the pressure of the gas to be adjusted on the basis of the flow rate measured in the flow rate sensor 67 acquired by the acquisition unit 31 and the requested flow rate. The controller 33 acquires a data table indicating the relationship between the flow rate of the gas and the pressure of the gas stored in the storage unit 35 in advance. The controller 33 extracts the pressure of the gas corresponding to the requested flow rate with use of the data table. The controller 33 calculates the flow rate and the pressure of the gas to be adjusted as with the embodiment described above.

The sensor 21 of the measuring apparatus 20 may be the first pressure sensor 65 or the second pressure sensor 68. At this time, the controller 33 controls the supplying of the gas on the basis of the pressure of the gas as the injection state of the injection medium S with respect to the workpiece W. In the storage unit 35 of the control apparatus 30, a model formula expressing a correlation between the pressure of the gas to be supplied to the nozzle 15 and the value of the residual stress is stored in advance. The controller 33 calculates a requested pressure that is a pressure corresponding to the required stress value acquired by the acquisition unit 31 with use of the model formula. The controller 33 calculates the flow rate and the pressure of the gas to be adjusted on the basis of the requested pressure and the pressure measured in the first pressure sensor 65 or the second pressure sensor 68 acquired by the acquisition unit 31. The controller 33 acquires a data table indicating the relationship between the flow rate of the gas and the pressure of the gas stored in the storage unit 35 in advance. The controller 33 extracts the pressure of the gas corresponding to the requested pressure with use of the data table. The controller 33 calculates the flow rate and the pressure of the gas to be adjusted as with the embodiment described above.

As described above, the controller 33 controls the supplying of the gas on the basis of sensing data such as the AE parameter indicating the injection state of the injection medium S with respect to the workpiece W, the flow rate of the gas, and the pressure of the gas. The controller 33 sets at least one type of data out of the sensing data and the processing conditions to be data indicating the injection state of the injection medium S with respect to the workpiece W, and controls the supplying of the gas on the basis of the data. The processing conditions may include an initial setting relating to the supplying of the gas and the injection medium S in the injection apparatus 10 in addition to the amount of injection time of the injection medium S, the injection time interval of the injection medium S described below, and information (the particle size, the hardness, and the like) relating to the injection medium S.

The injection system may execute shot blasting treatment as the injection treatment. In this case, the injection apparatus is a blasting processing apparatus, for example. The acquisition unit of the injection system acquires the injection state of the injection medium with respect to the workpiece as with the injection apparatus 10 in the acquiring. The acquisition unit of the injection system further acquires the front surface information relating to the front surface state requested for the workpiece as the processing conditions in the acquiring. The front surface information is information relating to the processing state of the workpiece that is the target of processing. The front surface information includes information relating to surface roughness, surface treatment, and shape, for example. The information relating to the surface roughness includes Ra (arithmetic average roughness), Pz (maximum height), and RzJIS (ten-point average roughness) defined by JIS B0601:2013, for example. The information relating to the surface treatment includes the degree of adhesion of mill scales or the degree of rust indicating the occurrence degree of rust, and the degree of rust removal indicating the degree of removal of dirt or adhering substances such as mill scales (black scales), rust, salts, and oil content, for example. The information relating to the shape includes a tolerance and an R value indicating the roundness of a corner of the workpiece W in rounding off, and the thickness of the root and the height of a burr in deburring, for example.

In the injecting in the injection apparatus that is the blasting processing apparatus, the supplying of the gas is controlled on the basis of the injection state of the injection medium, while the injection medium is intermittently injected to the workpiece as with the injecting (Step S3) of the injection apparatus 10. In the injecting, at least one of the flow rate and the pressure of the gas to be supplied is adjusted on the basis of the injection state of the injection medium, while the injection medium is intermittently injected to the workpiece as with the injecting (Step S3) of the injection apparatus 10. In the injecting, an injection time interval in the injection of the injection medium per time is adjusted on the basis of the injection state of the injection medium and the front surface information, while the injection medium is intermittently injected to the workpiece as with the injecting (Step S3) of the injection apparatus 10.

A correlation exists between the sensing data such as the AE parameter indicating the injection state of the injection medium, the flow rate of the gas, and the pressure of the gas and the front surface information of the workpiece. From the above, for example, a model formula expressing the correlation between the sensing data and the front surface information is stored in the storage unit of the control apparatus in advance. The control unit calculates a requested value that is a value of the sensing data corresponding to the front surface information acquired by the acquisition unit with use of the model formula, for example. The calculation is not limited to the model formula described above, and the requested value may be calculated by various other methods. For example, a requested value may be calculated on the basis of the data table indicating the relationship between the sensing data and the front surface information and the like. The control unit calculates the flow rate and the pressure of the gas supplied to the nozzle 15 on the basis of the sensing data and the requested value. The control unit calculates the flow rate and the pressure of the gas by an approach similar to that of the controller 33 described above. In this case, the injection method of the injection medium can intermittently inject the injection medium at an appropriate time interval, efficiently apply the surface treatment to the workpiece, and appropriately obtain the workpiece corresponding to the requested front surface state.

Examples

The present disclosure is further described in detail below by an example in order to describe the effects described above. The present disclosure is not limited to the example. In the example below, the injection method shown in FIG. 3 was performed under predetermined processing conditions, and the relationships between the residual stress value and the injection state of the injection medium S for the case where the injection medium S was continuously injected and the case where the injection medium S was intermittently injected were compared with each other.

Gravity air-blast equipment was used as the injection system of the example. As the injection medium, two types of which particle size was 0.3 mm and 0.6 mm were used. The injection medium of which material was conditioned cut wire and Vickers hardness was 500 HV were used for both. As the workpiece, a SUP9, which was a spring steel material and which was adjusted such that the Vickers hardness became 450 HV was used. In a test of continuous injection, the gas with the flow rate of about 600 L/minute and the pressure of about 0.34 MPa was supplied to the nozzle of the injection apparatus. The pressure was the pressure of the gas in the vicinity of the nozzle. In the test of intermittent injection, the injection medium was intermittently injected while changing the flow rate of the gas with time such that the amount of gas that was 20% or more and 60% or less of the total amount of the gas injected when the injection medium was continuously injected was obtained and the maximum value of the flow rate of the gas at the time of injection per time became about 600 L/minute. The injection time interval of the gas at the time of the intermittent injection was about 0.5 seconds.

FIG. 4 is a graph showing one example of a relationship between the residual stress and the depth of the workpiece. The ordinate indicates the residual stress (L/min) and the abscissa indicates the depth (m) in FIG. 4. The results of the continuous injection indicated by broken lines and the results of intermittent injection indicated by solid lines indicate substantially the same residual stress distribution regardless of the particle size of the injection medium. As above, injection was able to be performed such that the residual stress distribution of the workpiece after the intermittent injection was the same as the residual stress distribution of the workpiece after the continuous injection. In the example, the result obtained when injection was performed with use of the injection medium of which particle size was 0.6 mm and such that the residual stress distribution of the workpiece after the intermittent injection became the same as the residual stress distribution of the workpiece after the continuous injection is shown below.

FIG. 5 is a graph showing one example of a relationship between the AE parameter and the amount of time. The ordinate indicates the AE parameter and the abscissa indicates the amount of time (seconds) in FIG. 5. FIG. 6 is a graph showing one example of a relationship between the pressure of the gas and the amount of time. The ordinate indicates the pressure (MPa) and the abscissa indicates the amount of time (seconds) in FIG. 6. FIG. 7 is a graph showing one example of a relationship between the flow rate of the gas and the amount of time. The ordinate indicates the flow rate (L/min) and the abscissa indicates the amount of time (seconds) in FIG. 7. The broken lines shown in FIG. 5 to FIG. 7 are the results of the continuous injection, and the circulation of the gas was started after about 3.5 seconds from the start of the test. The solid lines shown in FIG. 5 to FIG. 7 are the results of the intermittent injection, and the circulation of the gas was started after about 3 seconds from the start of the test. A numerical change of the AE parameter in FIG. 5 greatly occurred after about 6 seconds from when the test was started, but a numerical change of the pressure in FIG. 6 and the flow rate in FIG. 7 greatly occurred immediately after the start of the test. Those differences occurred because there was a lag from when the gas circulated in the pipe to when the injection medium S was injected by the nozzle 15. The results of the periods of time in which the numerical changes greatly occurred is focused on below.

As shown in FIG. 5, while the AE parameter of the continuous injection almost constantly transitioned at about 400, the AE parameter of the intermittent injection transitioned while fluctuating between about 100 and about 600. At this time, while the pressure of the continuous injection shown in FIG. 6 almost constantly transitioned at about 0.34 MPa, the pressure of the intermittent injection transitioned while fluctuating between about 0.34 MPa and about 0.53 MPa. While the flow rate of the continuous injection shown in FIG. 7 almost constantly transitioned at about 600 L/min, the flow rate of the intermittent injection transitioned while fluctuating between about 0 L/min and about 600 L/min. The total amount of the gas of the intermittent injection shown in FIG. 7 indicates the state of 60% of the total amount of the gas of the continuous injection.

As above, it became clear that the total amount of the gas supplied to the nozzle in the intermittent injection was able to be decreased to 60% of the total amount of the gas supplied to the nozzle in the continuous injection when injection was performed such that the residual stress distribution of the workpiece after the intermittent injection became the same as the residual stress distribution of the workpiece after the continuous injection.

The residual stress applied to the workpiece was measured by performing a test by changing the total amount of the gas to be supplied to be 20% or more and less than 100% and using the same conditions as the test described above for the other conditions. The residual stress here was an integrated value in the residual stress distribution of the workpiece. As a result, it also became clear that the intermittent injection was able to efficiently apply the residual stress to the workpiece \V with a total amount that is smaller than that of the continuous injection when the total amount of the gas in the intermittent injection was 20% or more and less than 100% of the total amount of the gas in the continuous injection.

Claims

1. An injection method of injecting an injection medium to a workpiece with gas, the injection method comprising:

acquiring an injection state of the injection medium with respect to the workpiece; and

injecting intermittently the injection medium to the workpiece while controlling supplying of the gas on a basis of the injection state of the injection medium.

2. The injection method according to claim 1, wherein the injecting includes intermittently injecting the injection medium to the workpiece while adjusting at least one of a flow rate and a pressure of the gas to be supplied on a basis of the injection state of the injection medium.

3. The injection method according to claim 1, wherein:

the acquiring further acquires a residual stress value requested for the workpiece; and

the injecting includes intermittently injecting the injection medium to the workpiece while adjusting an injection time interval in injection of the injection medium per time on a basis of the injection state of the injection medium and the residual stress value.

4. The injection method according to claim 2, wherein:

the acquiring further acquires a residual stress value requested for the workpiece; and

the injecting includes intermittently injecting the injection medium to the workpiece while adjusting an injection time interval in injection of the injection medium per time on a basis of the injection state of the injection medium and the residual stress value.

5. The injection method according to claim 1, wherein:

the acquiring further acquires front surface information relating to a front surface state requested for the workpiece; and

the injecting includes intermittently injecting the injection medium to the workpiece while adjusting an injection time interval in injection of the injection medium per time on a basis of the injection state of the injection medium and the front surface information.

6. The injection method according to claim 2, wherein:

the acquiring further acquires front surface information relating to a front surface state requested for the workpiece; and

the injecting includes intermittently injecting the injection medium to the workpiece while adjusting an injection time interval in injection of the injection medium per time on a basis of the injection state of the injection medium and the front surface information.

7. The injection method according to claim 3, wherein:

the acquiring further acquires front surface information relating to a front surface state requested for the workpiece; and

the injecting includes intermittently injecting the injection medium to the workpiece while adjusting an injection time interval in injection of the injection medium per time on a basis of the injection state of the injection medium and the front surface information.

8. The injection method according to claim 4, wherein:

the acquiring further acquires front surface information relating to a front surface state requested for the workpiece; and

the injecting includes intermittently injecting the injection medium to the workpiece while adjusting an injection time interval in injection of the injection medium per time on a basis of the injection state of the injection medium and the front surface information.

9. An injection system of an injection medium, the injection system comprising:

an injection apparatus configured to inject the injection medium to a workpiece with gas;

a measuring apparatus configured to measure an injection state of the injection medium with respect to the workpiece by the injection apparatus; and

a control apparatus configured to control the injection apparatus, wherein the control apparatus includes: an acquisition unit configured to acquire the injection state of the injection medium from the measuring apparatus; and an injection control unit configured to control the injection apparatus such that the injection apparatus intermittently injects the injection medium to the workpiece and configured to control supplying of the gas on a basis of the injection state of the injection medium.