Method and system for spraying abrasive material

Abstract

To provide an injection method of a projection material which inhibits increase in an amount of supply of a gas used for injection of a projection material, and to provide an injection system of the projection material.SOLUTION: An injection method of a projection material is an injection method in which the projection material is injected to a workpiece with gas. The injection method comprises: a step in which an injection state of the projection material to the workpiece is acquired; and a step in which supply of the gas is controlled on a basis of the injection state of the projection material and the projection material is injected to the workpiece intermittently.SELECTED DRAWING: Figure 3

Description

[[Technical Field]]

[0001] The present disclosure relates to a blasting material injection method and a blasting material injection system. [[Background Art]]

[0002] Conventionally, there has been known an apparatus that performs surface treatment on a workpiece by injecting a blasting material onto the workpiece (object to be processed). For example, Patent Document 1 describes a sand blasting apparatus that injects a mixed fluid of high-pressure gas and an abrasive. This apparatus is supplied with high-pressure gas and the abrasive, and includes an abrasive injection nozzle that continuously injects the abrasive. [[Prior Art Literature]] [[Patent Literature]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Application Publication No. 2004-154894 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] In the sand blasting apparatus described in Patent Document 1, the supply amount of gas increases in accordance with the injection time, which may increase power consumption in a supply source that supplies the gas. The present disclosure provides a blasting material injection method and a blasting material injection system that suppress an increase in the supply amount of gas used for injecting the blasting material. [[Means for Solving the Problem]]

[0005] A blasting material injection method according to the present disclosure is a method for injecting a blasting material together with gas onto a workpiece, and includes the following steps (1) and (2): (1) A step of acquiring an injection state of the blasting material with respect to the workpiece. (2) A step of controlling the supply of gas based on the injection state of the blasting material, and intermittently injecting the blasting material onto the workpiece.

[0006] A projectile injection system relating to other aspects of this disclosure comprises an injection device, a measuring device, and a control device. The injection device injects the projectile together with a gas onto a workpiece. The measuring device measures the injection state onto the workpiece by the injection device. The control device controls the injection device. The control device has an acquisition unit and an injection control unit. The acquisition unit acquires the injection state onto the workpiece from the measuring device. The injection control unit manages the supply of gas based on the injection state onto the workpiece and controls the injection device to intermittently inject the projectile onto the workpiece. [Effects of the Invention]

[0007] According to this disclosure, it is possible to suppress an increase in the supply amount of gas used for injecting the projectile. [Brief explanation of the drawing]

[0008] [Figure 1] This figure schematically shows an injection system according to one embodiment. [Figure 2] This block diagram shows the functional configuration of a projectile injection system according to one embodiment. [Figure 3] This is a flowchart showing a method for spraying a projectile according to one embodiment. [Figure 4] This graph shows an example of the relationship between residual stress and depth in a workpiece. [Figure 5] This graph shows an example of the relationship between AE parameters and time. [Figure 6] This graph shows an example of the relationship between gas pressure and time. [Figure 7] This graph shows an example of the relationship between gas flow rate and time. [Modes for carrying out the invention]

[0009] [Summary of the embodiments of this disclosure] First, an overview of the embodiments of this disclosure will be provided.

[0010] (Clause 1) A method for spraying a projectile according to one aspect of the present disclosure is a method for spraying a projectile together with a gas onto a workpiece, comprising the following steps (1) and (2). (1) A step to obtain the state of the spraying of the projectile onto the workpiece. (2) A process of intermittently spraying the abrasive material onto a workpiece by controlling the gas supply based on the spraying state of the abrasive material.

[0011] In this abrasive material injection method, the gas supply is managed based on the abrasive material injection state, and the abrasive material is intermittently injected onto the workpiece along with the gas. By appropriately managing the gas supply based on the abrasive material injection state, this method can ensure an appropriate amount of abrasive material that contributes to the surface treatment of the workpiece while reducing the amount of abrasive material that does not contribute to the surface treatment. As a result, this abrasive material injection method can properly treat the workpiece surface, similar to, for example, the case of continuous abrasive material injection. Furthermore, by managing the abrasive material injection state, it is possible to monitor whether or not the workpiece surface has been properly treated, thereby confirming the accuracy of the workpiece processing. In addition, by intermittently injecting the abrasive material, this abrasive material injection method allows for periods when the abrasive material is not injected, compared to the case of continuous abrasive material injection. Therefore, this abrasive material injection method can suppress an increase in the amount of gas supplied for abrasive material injection.

[0012] (Clause 2) In the spraying method for the abrasive material described in Clause 1, the spraying step may involve adjusting at least one of the flow rate and pressure of the supplied gas based on the spraying state of the abrasive material, and intermittently spraying the abrasive material onto the workpiece. In this case, the spraying method for the abrasive material sprays the abrasive material with an appropriate output based on at least one of the adjusted flow rate and pressure. In this spraying method for the abrasive material, even if the amount of gas supplied and the amount of abrasive material sprayed are reduced compared to the case of continuous spraying of the abrasive material, the surface treatment of the workpiece is performed by the abrasive material sprayed with an appropriate output. As a result, this spraying method for the abrasive material can appropriately perform surface treatment on the workpiece, for example, in the same way as when the abrasive material is sprayed continuously. Furthermore, this spraying method for the abrasive material can appropriately perform surface treatment on the workpiece with a smaller gas supply in the same amount of time as when the abrasive material is sprayed continuously.

[0013] (Clause 3) In the spraying method for a projectile described in Clause 1 or 2, the acquisition step may further acquire the residual stress value required for the workpiece, and the spraying step may adjust the spraying time interval in each spray of the projectile based on the spraying state of the projectile and the residual stress value, and intermittently spray the projectile onto the workpiece. In this case, this spraying method for a projectile can intermittently spray the projectile at appropriate time intervals, efficiently perform surface treatment on the workpiece, and appropriately obtain a workpiece to which residual stress corresponding to the required residual stress value has been applied.

[0014] (Clause 4) In the spraying method for a projectile described in Clause 1 or 2, the acquisition step may further acquire surface information relating to the surface condition required for the workpiece, and the spraying step may adjust the spraying time interval in each spray of the projectile based on the spraying state of the projectile and the surface information, and intermittently spray the projectile onto the workpiece. In this case, this spraying method for a projectile can intermittently spray the projectile at appropriate time intervals, efficiently perform surface treatment on the workpiece, and appropriately obtain a workpiece corresponding to the required surface condition.

[0015] (Clause 5) A blasting material injection system according to another aspect of the present disclosure includes an injection device, a measuring device, and a control device. The injection device injects a blasting material together with gas toward a workpiece. The measuring device measures an injection state of the blasting material onto the workpiece by the injection device. The control device controls the injection device. The control device includes an acquisition unit and an injection control unit. The acquisition unit acquires the injection state of the blasting material from the measuring device. The injection control unit manages the supply of gas based on the injection state of the blasting material, and controls the injection device to intermittently inject the blasting material toward the workpiece. This blasting material injection system achieves the same effect as the blasting material injection method described in Clause 1.

[0016] [Example of Embodiment of the Present Disclosure] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and overlapping descriptions will not be repeated. The dimensional ratios in the drawings do not necessarily match those described.

[0017] [Outline of Injection System] FIG. 1 is a diagram schematically showing a blasting material injection system according to an embodiment. The blasting material S injection system 1 shown in FIG. 1 (hereinafter sometimes simply referred to as "injection system 1") injects (projects) a blasting material together with gas toward a workpiece W (object to be processed) in order to process the workpiece. In the present embodiment, the process of injecting the blasting material S in the injection system 1 is referred to as "injection process". The injection process includes shot blasting for purposes such as scale removal, deburring, and surface roughness adjustment, and shot peening for the purpose of imparting residual compressive stress to a workpiece. As an example, the injection process of the present embodiment refers to shot peening process.

[0018] As shown in FIG. 1, the injection system 1 includes an injection device 10, a measuring device 20 (sensing unit), and a control device 30. The injection device 10 injects a projection material S together with gas onto a workpiece W. The injection device 10 processes the surface of the workpiece W by injecting the projection material S onto the workpiece W and causing the projection material S to collide with the workpiece W. For example, the injection device 10 is a shot peening device that imparts compressive residual stress to the surface of the workpiece W. Examples of the workpiece W subjected to injection processing by the injection device 10 include automobile parts such as cylinder heads and crankshafts, gears, and molds, but the workpiece W is not limited thereto. Imparting compressive residual stress to the surface of the workpiece W by the injection processing improves the fatigue properties of the workpiece W.

[0019] The injection device 10 is a gravity type (suction type) shot peening device. Note that the injection device 10 may be a direct pressure type shot peening device. As the projection material S projected onto the workpiece W, for example, steel balls are used. The particle size of the steel balls is appropriately selected according to the compressive residual stress required for (to be imparted to) the workpiece W.

[0020] The injection device 10 includes a projection material tank 11, a compressor 12, and a nozzle 15. The projection material tank 11 stores the projection material S. The projection material tank 11 is connected to the nozzle 15 via a pipe 60. The projection material tank 11 is provided with an outflow port 11A through which the projection material S flows out. An openable / closable cut gate 61 is provided at the outflow port 11A. The pipe 60 is connected to the outflow port 11A via the cut gate 61. The pipe 60 may be provided with a regulating valve that adjusts the amount of the projection material S injected from the nozzle 15.

[0021] 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 piping 62. An air filter 63 is provided in the piping 62 between the compressor 12 and the nozzle 15. The air filter 63 removes dust from the compressed gas supplied from the compressor 12 to the nozzle 15. A regulator 64 is provided in the piping 62 between the air filter 63 and the nozzle 15. The regulator 64 is a valve that reduces the compressed gas supplied from the compressor 12 to the nozzle 15 to a predetermined pressure.

[0022] A first pressure sensor 65 is provided in the piping 62 between the regulator 64 and the nozzle 15. The first pressure sensor 65 measures the pressure of the compressed gas whose pressure has been regulated by the regulator 64. A solenoid valve 66 is provided in the piping 62 between the first pressure sensor 65 and the nozzle 15. The solenoid valve 66 controls the passage or obstruction of the compressed gas supplied from the compressor 12 to the nozzle 15. A flow rate sensor 67 is provided in the piping 62 between the solenoid valve 66 and the nozzle 15. 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 the piping 62 between the flow rate sensor 67 and the nozzle 15. The second pressure sensor 68 measures the pressure of the compressed gas after it has passed through the solenoid valve 66 (flow rate sensor 67).

[0023] The injection device 10 has an intermittent injection unit 69 located between the second pressure sensor 68 and the nozzle 15 in the piping 62. The intermittent injection unit 69 is provided upstream (compressor 12 side) of the mixing section 15A, which will be described later. The intermittent injection unit 69 intermittently injects compressed gas supplied from the compressor 12. The intermittent injection unit 69 is controlled electrically or mechanically. In this embodiment, the intermittent injection unit 69 has, for example, an electrically controlled valve. The intermittent injection unit 69 adjusts the flow rate of compressed gas supplied to the nozzle 15 to a predetermined flow rate.

[0024] Thus, the first pressure sensor 65, the flow sensor 67, and the second pressure sensor 68 are located in the piping 62 upstream of the nozzle 15 (mixing section 15A, described later) (on the compressor 12 side). The flow sensor 67 is located in the piping 62 near the source pressure of the pressure-adjusted gas and is situated near the regulator 64. The intermittent injection unit 69 is located, for example, upstream of the nozzle 15 (mixing section 15A, described later) (on the compressor 12 side) in the piping 62. Note that the order of the components in the piping 62 is not limited to these.

[0025] The cut gate 61, regulator 64, first pressure sensor 65, solenoid valve 66, flow sensor 67, second pressure sensor 68, and intermittent injection unit 69 in the injection system 1 are connected to the control device 30 in a communicative manner. The flow sensor 67 converts the measured flow rate into digital data and outputs it to the control device 30. The first pressure sensor 65 and the second pressure sensor 68 convert the measured pressure into digital data and output it to the control device 30.

[0026] The nozzle 15 is provided at the ends of the pipes 60 and 62 and injects the abrasive material S supplied from the abrasive material tank 11 as a solid-gas two-phase flow together with compressed gas. Inside the nozzle 15, the connection of the pipes 60 and 62 to the nozzle 15 constitutes a mixing section 15A where the abrasive material S supplied from the abrasive material tank 11 and the compressed gas supplied from the compressor 12 are mixed.

[0027] The nozzle 15 is located inside the cabinet 70. The cabinet 70 defines a processing chamber 70s, which is a space for processing the workpiece W. The workpiece W is placed on a mounting table 71 inside the processing chamber 70s. When spraying the workpiece W, the workpiece W is placed inside the processing chamber 70s, and the spraying material S is projected from the nozzle 15 towards the workpiece inside the processing chamber 70s, causing the spraying material S to collide with the workpiece W.

[0028] Although not shown in Figure 1, the spraying device 10 may further include a dust collector, a classifier, and a circulation device for reusing the used abrasive material S. The dust collector is connected to the processing chamber 70s via the classifier and transfers the abrasive material S and workpiece chips that have fallen to the bottom of the processing chamber 70s to the classifier by suction. The classifier is, for example, a cyclone-type classifier that receives the abrasive material S and workpiece chips and classifies them into particles that can be reused as abrasive material S and particles that cannot be used as abrasive material S. The circulation device returns the reusable abrasive material S to the abrasive material tank 11 via a packet elevator, screw conveyor, separator, etc.

[0029] The measuring device 20 detects the spraying state of the projectile material S in the spraying device 10. Figure 2 is a block diagram showing the functional configuration of a projectile material spraying system according to one embodiment. As shown in Figures 1 and 2, the measuring device 20 includes a sensor 21, an AD conversion unit 22, and a communication unit 23. The sensor 21 acquires characteristic quantities indicating the spraying state of the projectile material S. The sensor 21 in this embodiment is, for example, an AE sensor. The sensor 21 is fixed to the nozzle 15 and measures the acoustic emission (AE) generated when the projectile material S is projected from the nozzle 15 of the spraying device 10, and outputs a signal waveform related to the measured AE (hereinafter referred to as "AE signal waveform"). The AE signal waveform is a signal waveform related to vibrations or elastic waves such as sound waves that are generated when the projectile material S passes through (sprays) the nozzle 15. The AE signal waveform includes characteristic parameters related to the intensity of the spraying process, such as amplitude, duration, AE count, rise time, AE count rate, and average frequency.

[0030] The AD conversion unit 22 converts the AE signal waveform output from the sensor 21 into digital data and outputs it. The communication unit 23 is a communication module capable of wireless communication such as LAN, Bluetooth (registered trademark), and Wi-Fi. The communication unit 23 acquires the digital data of the AE signal waveform measured by the sensor 21 (hereinafter referred to as signal data) from the AD conversion unit 22 and transmits the signal data to the control device 30 via wireless communication. The first pressure sensor 65, the flow sensor 67, and the second pressure sensor 68 may be equipped with an AD conversion unit and a communication unit similar to the AD conversion unit 22 and communication unit 23 included in the measuring device 20.

[0031] The control device 30 controls the entire injection system 1 of the projectile material S. The control device 30 is configured as a PLC (Programmable Logic Controller) as an example. The control device 30 may also be configured as a normal computer system including a CPU (Central Processing Unit), main memory such as RAM (Random Access Memory) and ROM (Read Only Memory), input devices such as a touch panel and keyboard, output devices such as a display, and auxiliary storage devices such as a hard disk.

[0032] The control device 30 is provided with, for example, an operation panel that can be operated by an operator. The control device 30 is connected to the injection device 10 and the measuring device 20 in a communicative manner. The control device 30 outputs control signals to the injection device 10 and the measuring device 20 to control the operation of each component. The control device 30 reads a pre-prepared program and operates the injection device 10 and the measuring device 20. The control device 30 may also operate the injection device 10 and the measuring device 20 in response to operator commands received via the operation panel (not shown). The control device 30 allows an operator to input commands and perform other operations to manage the injection device 10 using an input device. The control device 30 visualizes and displays the operating status of the injection device 10 using an output device.

[0033] In the injection system 1, for example, in order to manage the injection of the abrasive material S to the workpiece W appropriately and intermittently by the injection device 10 (so that the workpiece W is appropriately given residual stress corresponding to the required stress value described later), an injection process is performed on the workpiece W before processing, and at least one of the AE parameters, flow rate, and pressure is measured. The control device 30 of this embodiment periodically manages (adjusts) the injection conditions based on the AE parameters. The injection conditions are the output conditions set for the injection device 10 to inject the abrasive material S, and include, for example, the gas supply conditions. The injection conditions include, for example, the flow rate and pressure of the gas supplied to the nozzle 15, and the injection time and injection time interval of the abrasive material S. This management is performed once or multiple times before the injection process is performed on the workpiece W. The control device 30 controls the injection device 10 to project the abrasive material S under the managed (adjusted) injection conditions. The control device 30 is communicatively connected to the intermittent injection unit 69 in the injection device 10 and outputs a control signal to supply gas intermittently to the nozzle 15 according to a program or command operation. The details are explained below.

[0034] As shown in Figure 2, the control device 30 comprises 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 projectile material S by the injection device 10 from the measuring device 20. The acquisition unit 31 acquires signal data transmitted from the communication unit 23 of the measuring device 20 as an example of the injection state of the projectile material S by the injection device 10. Furthermore, the acquisition unit 31 acquires the gas flow rate measured by the flow rate sensor 67 and the gas pressure measured by at least one of the first pressure sensor 65 and the second pressure sensor 68.

[0035] The acquisition unit 31 acquires the processing conditions for the workpiece W to which the abrasive material S is sprayed in the spraying device 10. The acquisition unit 31 may acquire, for example, processing conditions input by the operator of the spraying device 10, or processing conditions that have been previously stored in the storage unit 35. As described above, the abrasive material S projected from the nozzle 15 of the spraying device 10 collides with the workpiece W. The force exerted by the impact of the abrasive material S on the surface of the workpiece W causes a counteracting force to be generated in the workpiece W, and as a result, residual stress (compressive residual stress) is imparted to the workpiece W. Here, the residual stress to be imparted to the workpiece W is determined according to the application of the workpiece W. In order to impart the required residual stress to the workpiece W, it is necessary to spray the workpiece W with appropriate strength at appropriate time intervals. The acquisition unit 31 acquires the required stress value (an example of a residual stress value), which is the residual stress required for the workpiece W to which the abrasive material S is sprayed in the spraying device 10, as a processing condition. The required stress value is, for example, the integral value in the residual stress distribution shown by residual stress and depth, the surface residual stress, the peak value of compressive residual stress and / or peak depth. The acquisition unit 31 may acquire the injection time of the abrasive material S described later, the injection time interval of the abrasive material S described later, and information about the abrasive material S (particle size, hardness, etc.) as processing conditions. Hereinafter, in order to obtain the required stress value in the workpiece W, the case in which the abrasive material S is intermittently injected into the workpiece W at a predetermined gas flow rate and pressure will be expressed as "intermittent injection". Also, hereafter, in order to obtain the required stress value in the workpiece W, the case in which the abrasive material S is continuously injected into the workpiece W at a predetermined gas flow rate and pressure will be expressed as "continuous injection".

[0036] The injection control unit 32 manages the supply of gas based on the injection state of the abrasive material S and controls the injection device 10 to intermittently inject the abrasive material S onto the workpiece W. The injection control unit 32 includes a management unit 33 and an intermittent injection control unit 34. The management unit 33 manages the supply of gas based on the injection state of the abrasive material S onto the workpiece W. The management of the gas supply includes the injection control unit 32 setting and adjusting at least one of the flow rate and pressure of the supplied gas after the measuring device 20 detects a characteristic quantity related to the gas supply, including at least one of the AE parameter, flow rate, and pressure. The management of the gas supply also includes the injection control unit 32 controlling the supply of gas at the flow rate and pressure before detection after the measuring device 20 detects the above-mentioned characteristic quantity. The management of the gas supply may also include the injection control unit 32 predicting and determining whether appropriate injection is being performed in the injection device 10 after the measuring device 20 detects the above-mentioned characteristic quantity. In this embodiment, the control unit 33 manages the gas flow rate and pressure to obtain the required stress value in the workpiece W, based on the AE parameters, which are shown as the spraying state of the projectile material S, and the processing conditions of the workpiece W.

[0037] The management unit 33 calculates AE parameters from the AE signal waveform included in the signal data acquired by the acquisition unit 31. Examples of AE parameters include the amplitude, duration, AE count, or rise time of the AE signal waveform. Alternatively, the peak value, average value, or RMS value of the AE signal waveform may be used as AE parameters. A correlation exists between the AE parameters and the residual stress value of the workpiece W. For this reason, the storage unit 35 of the control device 30 pre-stores a model equation representing the correlation between the AE parameters and the residual stress value. The management unit 33 uses this model equation to calculate the required AE parameter, which corresponds to the required stress value acquired by the acquisition unit 31. The required AE parameter may be calculated using various other methods, not limited to the model equation described above. For example, the required AE parameter may be calculated based on a data table showing the relationship between the AE parameters and the residual stress value of the workpiece W.

[0038] The control unit 33 calculates the flow rate and pressure of the gas supplied to the nozzle 15 based on the AE parameters calculated from the signal data acquired by the acquisition unit 31 and the requested AE parameters. The control unit 33 acquires data tables showing the relationship between the AE parameters and the flow rate of the supplied gas, and data tables showing the relationship between the AE parameters and the pressure of the supplied gas, which are stored in the storage unit 35 in advance. The control unit 33 uses these data tables to extract the flow rate and pressure of the gas corresponding to the requested AE parameters.

[0039] The control unit 33 calculates the difference between the gas flow rate at the time of signal data acquisition and the gas flow rate corresponding to the required AE parameter, and determines the value of the flow rate to adjust (increase or decrease) from the measured flow rate at the time of AE parameter calculation. As an example of the gas flow rate corresponding to the required AE parameter, the control unit 33 assigns the maximum value of the gas flow rate during continuous injection, which allows the required AE parameter (required stress value) to be obtained, to the maximum value of the flow rate during intermittent injection.

[0040] The control unit 33 calculates the difference between the gas pressure at the time of signal data acquisition at at least one of the first pressure sensor 65 and the second pressure sensor 68 and the gas pressure corresponding to the required AE parameter, and determines the value of the pressure to adjust (increase or decrease). As an example of the gas pressure corresponding to the required AE parameter, the control unit 33 assigns, for example, the maximum value of the gas pressure during continuous injection that can obtain the required AE parameter (required stress value) to the minimum value of the pressure during surface treatment of the workpiece W by intermittent injection. This minimum value of pressure is the minimum value from when the process of applying residual stress to the workpiece W is started and intermittent gas supply begins until the intermittent gas supply ends.

[0041] The control unit 33 does not need to calculate the flow rate and pressure values ​​to be adjusted separately. The control unit 33 may, for example, determine the corresponding pressure value by determining the flow rate value to be adjusted. The control unit 33 may, for example, determine the corresponding flow rate value by determining the pressure value to be adjusted. Alternatively, the control unit 33 may directly determine the flow rate and pressure values ​​to be adjusted from the difference between the AE parameter and the required AE parameter. The control unit 33 stores the calculated gas flow rate and pressure in the storage unit 35.

[0042] Furthermore, the control unit 33 sets the injection time of the abrasive material S and the injection time interval of the abrasive material S until a predetermined residual stress is applied to the workpiece W. The injection time of the abrasive material S may be the gas supply time. For example, the control unit 33 sets the required time during continuous injection as the injection time during intermittent injection. The injection time interval of the abrasive material S may be the gas supply time interval. When the injection device 10 intermittently injects the abrasive material S, it repeats the operation of starting and stopping the supply of gas to the nozzle 15 multiple times within the injection time of the abrasive material S. The injection time interval of the abrasive material S refers to the injection time for each injection of the abrasive material S, and specifically refers to the time from the start to the stop of gas supply for each injection. The injection time interval is, for example, 0.5 seconds. Within the injection time of the abrasive material S, the injection time interval of the abrasive material S may be constant or may differ for each injection of the abrasive material S. When the injection device 10 intermittently injects the abrasive material S, the injection time interval of the abrasive material S required to impart the same residual stress to the workpiece W as during continuous injection is predetermined in correspondence with at least one of the AE parameters, flow rate, and pressure. This injection time interval may also be predetermined in correspondence with each required stress value required for the workpiece W. The control unit 33 obtains, for example, a data table that shows the relationship between the flow rate or pressure of the supplied gas and the injection time interval of the abrasive material S, which is stored in the storage unit 35 in advance. The control unit 33 uses, for example, this data table to set the injection time interval corresponding to the calculated gas flow rate or pressure.

[0043] The intermittent injection control unit 34 controls the injection device 10 to intermittently inject the abrasive material S onto the workpiece W based on the injection conditions controlled by the control unit 33. The intermittent injection control unit 34 controls the valve in the intermittent injection unit 69 so that, for example, the gas flow rate calculated by the control unit 33 is supplied to the nozzle 15. The intermittent injection control unit 34 controls the regulator 64 so that, for example, the gas pressure calculated by the control unit 33 is supplied to the nozzle 15. The intermittent injection control unit 34 obtains the pressure of the compressed gas generated from the compressor 12 and reduces the gas pressure to the pressure calculated by the control unit 33. The intermittent injection control unit 34 adjusts and opens / closes the degree to which the valve in the intermittent injection unit 69 is open during the injection time so that the injection time interval is set by the control unit 33. The intermittent injection control unit 34 adjusts and opens / closes the degree to which the valve in the intermittent injection unit 69 is open as set by the control unit 33.

[0044] [Method of spraying the projectile material] Next, a method for spraying the abrasive material S onto a workpiece W using the spraying system 1 described above will be explained. Figure 3 is a flowchart of a method for spraying the abrasive material according to one embodiment. The method of spraying the abrasive material S is performed, for example, when the spraying device 10 experimentally sprays the abrasive material S onto the workpiece W for a predetermined spraying time. In this flowchart, the execution time (spraying time) of the method of spraying the abrasive material S in the spraying device 10 is predetermined.

[0045] In this method, first, the acquisition unit 31 of the control device 30 acquires the spraying state of the projectile material S from the measuring device 20 (Step S1: an example of the acquisition process). The acquisition unit 31 acquires AE parameters from the measuring device 20. Furthermore, the acquisition unit 31 acquires the gas flow rate measured by the flow sensor 67 and the gas pressure measured by at least one of the first pressure sensor 65 and the second pressure sensor 68.

[0046] Next, the injection control unit 32 manages the gas supply based on the injection state of the abrasive material S and controls the injection device to intermittently inject the abrasive material S onto the workpiece W (Step S3: an example of the injection process). The control unit 33 calculates the flow rate and pressure of the gas supplied to the nozzle 15, as well as the injection time interval of the abrasive material S, based on the AE parameters indicating the injection state of the abrasive material S and the requested AE parameters. The intermittent injection control unit 34 adjusts the regulator 64 and the intermittent injection unit 69 to match the flow rate and pressure, and the injection time interval of the abrasive material S.

[0047] Next, the intermittent injection control unit 34 determines whether a predetermined injection time has elapsed (step S5). If the intermittent injection control unit 34 determines that the predetermined injection time has not elapsed, it returns to step S1 and adjusts the injection conditions of the projectile material S. If the intermittent injection control unit 34 determines that the predetermined injection time has elapsed, it terminates the series of processes for this injection method.

[0048] [Summary of Embodiments] In the injection system 1 and the injection method for the abrasive material S of this embodiment, the supply of gas is managed based on the injection state of the abrasive material S, and the abrasive material S is intermittently injected onto the workpiece W along with the gas. This injection method for the abrasive material S appropriately manages the supply of gas based on the injection state of the abrasive material S, thereby ensuring an appropriate amount of abrasive material S that contributes to the surface treatment of the workpiece W while reducing the amount of abrasive material S that does not contribute to the surface treatment of the workpiece W. As a result, this injection method for the abrasive material S can appropriately apply surface treatment to the workpiece W, for example, in the same way as continuous injection. Furthermore, by managing the injection state of the abrasive material S, it is possible to monitor whether or not the surface treatment of the workpiece W has been appropriately applied, and the accuracy of the processing of the workpiece W can be confirmed. Moreover, this injection method for the abrasive material S allows for periods when the abrasive material S is not injected compared to continuous injection due to intermittent injection. Therefore, this injection method for the abrasive material S can suppress an increase in the amount of gas supplied for the injection of the abrasive material S. This makes it possible to suppress the increase in power consumption when supplying compressed gas in the compressor 12, and also enables miniaturization of the compressor 12.

[0049] In the spraying process (step S3), at least one of the flow rate and pressure of the supplied gas is adjusted based on the spraying state of the spraying material S, and the spraying material is intermittently sprayed onto the workpiece W. In this case, the spraying method of the spraying material S ensures that the spraying material S is sprayed with an appropriate output based on at least one of the adjusted flow rate and pressure. With this spraying method of the spraying material S, even if the amount of gas supplied and the amount of spraying material S sprayed are reduced compared to the case of continuous spraying, the surface treatment of the workpiece W is performed by the spraying material S sprayed with an appropriate output. As a result, this spraying method of the spraying material S can appropriately treat the surface of the workpiece W, just as it can with continuous spraying. For example, with this spraying method of the spraying material S, the surface treatment of the workpiece W can be appropriately performed with a smaller amount of gas supplied, while taking the same amount of time as continuous spraying. Specifically, by intermittently injecting the abrasive material S within the same timeframe as the continuous injection time, the total flow rate of gas supplied to the nozzle 15 can be reduced to between 20% and 100% of the total flow rate of gas supplied continuously. In the abrasive material S injection method using the injection system 1 of this embodiment, the injection conditions in intermittent injection (such as the flow rate and pressure of the supplied gas) can be, for example, made to correspond to the difference between the total amount of gas during continuous injection and the total amount of gas during intermittent injection. Alternatively, the injection conditions in intermittent injection can be, for example, made to correspond to the ratio of the integral value of the residual stress distribution of the workpiece W during intermittent injection to the integral value of the residual stress distribution of the workpiece W during continuous injection. Therefore, in the abrasive material S injection method using the injection system 1 of this embodiment, by selecting predetermined injection conditions, it is possible to obtain a workpiece W with the same residual stress as during continuous injection, even during intermittent injection, and to reduce the total amount of gas supplied to the nozzle 15.

[0050] The acquisition step (step S1) further acquires the residual stress value required for the workpiece, and the spraying step (step S3) adjusts the spraying time interval for each spray of the spraying material S based on the spraying state of the spraying material S and the residual stress value, and intermittently sprays the spraying material S onto the workpiece W. In this case, the spraying method of the spraying material S allows for intermittent spraying of the spraying material S at appropriate time intervals, enabling efficient surface treatment of the workpiece W, and allowing for the appropriate acquisition of a workpiece W with residual stress corresponding to the required residual stress value.

[0051] [Differentiation] Although various embodiments of the projectile injection system and projectile injection method have been described above, various modified forms can be constructed without changing the gist of the invention, and are not limited to the embodiments described above.

[0052] In the above embodiment, an AE sensor is used as the sensor 21 of the measuring device 20 to measure elastic waves as the projection material S passes through the nozzle 15. However, the measuring device 20 may also measure waves other than elastic waves and output a signal waveform related to those waves. Examples of sensors that measure waves other than elastic waves include vibration sensors, acceleration sensors, and shock sensors for measuring vibrations, ultrasonic sensors for measuring ultrasonic waves, electromagnetic sensors for measuring electromagnetics, eddy current sensors, laser displacement sensors, and ultrasonic sensors for measuring displacements, and color sensors for measuring colors.

[0053] When an AE sensor is used as sensor 21, the measuring device 20 does not have to be installed on the nozzle 15. The measuring device 20 may be installed around the workpiece W, for example, on the mounting table 71 of the workpiece W. The measuring device 20 outputs a signal relating to the waves generated by the collision of the projectile S projected from the spraying device 10 onto the workpiece W. Waves are a general term for waves generated when the projectile S collides with the workpiece W, and are a concept that includes elastic waves, vibrations, ultrasonic waves, and electromagnetic waves.

[0054] The sensor 21 of the measuring device 20 does not necessarily have to be located around the nozzle 15 and the workpiece W. The sensor 21 of the measuring device 20 may be replaced by a flow rate sensor 67. In this case, the control unit 33 manages the supply of gas based on the gas flow rate as the injection state of the projectile S to the workpiece W. The storage unit 35 of the control device 30 has a model equation in advance that represents the correlation between the gas flow rate supplied to the nozzle 15 and the residual stress value. The control unit 33 uses this model equation to calculate the required flow rate, which is the flow rate corresponding to the required stress value acquired by the acquisition unit 31. The control unit 33 calculates the gas flow rate and pressure to be adjusted based on the flow rate measured by the flow rate sensor 67 acquired by the acquisition unit 31 and the required flow rate. The control unit 33 acquires a data table that shows the relationship between the gas flow rate and the gas pressure, which is stored in the storage unit 35 in advance. The control unit 33 uses this data table to extract the gas pressure corresponding to the required flow rate. The control unit 33 calculates the gas flow rate and pressure to be adjusted in the same manner as in the embodiment described above.

[0055] The sensor 21 of the measuring device 20 may be a first pressure sensor 65 or a second pressure sensor 68. In this case, the control unit 33 manages the supply of gas based on the gas pressure as the injection state of the projectile material S to the workpiece W. The storage unit 35 of the control device 30 has a model equation in advance that represents the correlation between the pressure of the gas supplied to the nozzle 15 and the value of residual stress. The control unit 33 uses this model equation to calculate the required pressure, which is the pressure corresponding to the required stress value acquired by the acquisition unit 31. The control unit 33 calculates the flow rate and pressure of the gas to be adjusted based on the pressure measured by the first pressure sensor 65 or the second pressure sensor 68 acquired by the acquisition unit 31 and the required pressure. The control unit 33 acquires a data table that shows the relationship between the flow rate and pressure of the gas, which is stored in advance in the storage unit 35. The control unit 33 uses this data table to extract the flow rate of the gas corresponding to the required pressure. The control unit 33 calculates the flow rate and pressure of the gas to be adjusted in the same manner as in the embodiment described above.

[0056] As described above, the control unit 33 manages the supply of gas based on sensing data such as AE parameters indicating the injection state of the abrasive material S onto the workpiece W, gas flow rate, and gas pressure. The control unit 33 uses at least one type of data from the sensing data described above and processing conditions as data indicating the injection state of the abrasive material S onto the workpiece W, and manages the supply of gas based on this data. The processing conditions may include the injection time of the abrasive material S, the injection time interval of the abrasive material S described later, and information about the abrasive material S (particle size, hardness, etc.), as well as initial settings related to the supply of gas and abrasive material S in the injection device 10.

[0057] The spraying system may perform shot blasting as the spraying process. In this case, the spraying device is, for example, a blasting device. The acquisition unit of the spraying system acquires the spraying state of the projectile onto the workpiece in the acquisition process, similar to the spraying device 10. The acquisition unit of the spraying system further acquires surface information regarding the surface condition required for the workpiece as processing conditions in the acquisition process. Surface information refers to information regarding the processing state of the workpiece to be processed. Surface information includes, for example, information regarding surface roughness, surface processing, shape, etc. Information regarding surface roughness includes, for example, Ra (arithmetic mean roughness), Pz (maximum height), RzJIS (ten-point mean roughness), etc., as specified in JIS B0601:2013. Information regarding surface processing includes rust degree, which indicates the degree of mill scale adhesion or rust occurrence, and rust removal degree, which indicates the degree of removal of dirt or deposits such as mill scale (black scale), rust, salts, oil, etc. Information regarding the shape includes, for example, the R value and tolerance indicating the degree of rounding of the corners of the workpiece W in the R-gripping process, as well as the height and thickness of the base of the burr in the deburring process.

[0058] In the blasting process of the blasting device, the supply of gas is managed based on the blasting state of the abrasive material, and the abrasive material is intermittently blasted onto the workpiece, similar to the blasting process of the blasting device 10 (step S3). In this blasting process, at least one of the flow rate and pressure of the supplied gas is adjusted based on the blasting state of the abrasive material, and the abrasive material is intermittently blasted onto the workpiece. In this blasting process, the blasting time interval in each blast of the abrasive material is adjusted based on the blasting state of the abrasive material and surface information, and the abrasive material is intermittently blasted onto the workpiece, similar to the blasting process of the blasting device 10 (step S3).

[0059] A correlation exists between sensing data such as AE parameters indicating the spraying state of the abrasive material, gas flow rate, and gas pressure, and the surface information of the workpiece. Therefore, for example, a model equation representing the correlation between the sensing data and surface information is pre-stored in the control device's memory unit. The control unit uses this model equation to calculate a required value, which is the value of the sensing data corresponding to the surface information acquired by the acquisition unit. Note that the required value is not limited to the above-mentioned model equation and may be calculated using various other methods. For example, the required value may be calculated based on a data table showing the relationship between the sensing data and surface information. The control unit calculates the gas flow rate and pressure supplied to the nozzle 15 based on the sensing data and the required value. The control unit calculates the gas flow rate and pressure using the same method as the control unit 33 described above. In this case, this abrasive material spraying method allows for intermittent spraying of the abrasive material at appropriate time intervals, enabling efficient surface treatment of the workpiece and obtaining a workpiece corresponding to the required surface condition. [Examples]

[0060] The present disclosure will be further explained below with reference to examples in order to illustrate the above effects. The present disclosure is not limited to these examples. In the following examples, the spraying method shown in Figure 3 was carried out under predetermined processing conditions, and the relationship between the residual stress value and the spraying state of the spraying material S was compared when the spraying material S was sprayed continuously and when the spraying material S was sprayed intermittently.

[0061] A gravity-type air blast system was used as the injection system in the embodiment. Two types of abrasive material were used, with particle sizes of 0.3 mm and 0.6 mm, both made of conditioned cut wire with a Vickers hardness of 500 HV. The workpiece was SUP9 spring steel, adjusted to have a Vickers hardness of 450 HV. In the continuous injection test, gas at a flow rate of approximately 600 L / min and a pressure of approximately 0.34 MPa was supplied to the nozzle of the injection device. This pressure was the gas pressure near the nozzle. In the intermittent injection test, the abrasive material was injected intermittently by changing the gas flow rate over time so that the amount of gas injected was between 20% and 60% of the total amount of gas injected when continuously injecting the abrasive material, and the maximum gas flow rate per injection was approximately 600 L / min. The time interval between gas injections during intermittent injection was approximately 0.5 seconds.

[0062] Figure 4 is a graph showing an example of the relationship between residual stress and depth of a workpiece. The vertical axis of Figure 4 represents residual stress ( MPa The graph shows the results of continuous injection, indicated by a dashed line and a solid line. intermittent The spraying results show nearly identical residual stress distributions regardless of the particle size of the spray material. Thus, it is possible to spray the workpiece so that the residual stress distribution after intermittent spraying is the same as that after continuous spraying. In the following examples, a spray material with a particle size of 0.6 mm is used, and the results of spraying so that the residual stress distribution of the workpiece after intermittent spraying is the same as that of the workpiece after continuous spraying are shown.

[0063] Figure 5 is a graph showing an example of the relationship between AE parameters and time. In Figure 5, the vertical axis represents AE parameters, and the horizontal axis represents time (seconds). Figure 6 is a graph showing an example of the relationship between gas pressure and time. In Figure 6, the vertical axis represents pressure (MPa), and the horizontal axis represents time (seconds). Figure 7 is a graph showing an example of the relationship between gas flow rate and time. In Figure 7, the vertical axis represents flow rate (L / min), and the horizontal axis represents time (seconds). The dashed lines in Figures 5 to 7 represent the results of continuous injection, with gas flow starting approximately 3.5 seconds after the start of the test. The solid lines in Figures 5 to 7 represent the results of intermittent injection, with gas flow starting approximately 3 seconds after the start of the test. The large change in the numerical value of the AE parameters in Figure 5 occurs approximately 6 seconds after the start of the test, while the large change in numerical values ​​of pressure in Figure 6 and flow rate in Figure 7 occurs immediately after the start of the test. These differences occur because there is a lag between the time the gas flows through the piping and the time the abrasive material S is injected at the nozzle 15. Below, we will focus on the results during the time periods in which the relevant numerical changes occurred most significantly.

[0064] As shown in Figure 5, the AE parameter for continuous injection remains almost constant at approximately 400, while the AE parameter for intermittent injection fluctuates between approximately 100 and 600. At this time, the pressure for continuous injection shown in Figure 6 remains almost constant at approximately 0.34 MPa, while the pressure for intermittent injection fluctuates between approximately 0.34 MPa and 0.53 MPa. Furthermore, the flow rate for continuous injection shown in Figure 7 remains almost constant at approximately 600 L / min, while the flow rate for intermittent injection fluctuates between approximately 0 L / min and 600 L / min. The total amount of gas in intermittent injection shown in Figure 7 represents 60% of the total amount of gas in continuous injection.

[0065] Thus, it was found that when the residual stress distribution of the workpiece after intermittent injection is the same as that of the workpiece after continuous injection, the total amount of gas supplied to the nozzle during intermittent injection can be reduced to 60% of the total amount of gas supplied to the nozzle during continuous injection.

[0066] Furthermore, the total amount of gas supplied was varied between 20% and less than 100%, and the test was conducted under the same conditions as the above-mentioned test, and the residual stress applied to the workpiece was measured. Here, residual stress refers to the integral value of the residual stress distribution of the workpiece. As a result, it became clear that if the total amount of gas in intermittent injection is between 20% and less than 100% of the total amount of gas in continuous injection, intermittent injection can efficiently apply residual stress to the workpiece W with a smaller total amount than continuous injection. [Explanation of Symbols]

[0067] 1...Injection system, 10...Injection device, 12...Compressor, 15...Nozzle, 15A...Mixing unit, 20...Measuring device, 21...Sensor, 22...AD conversion unit, 23...Communication unit, 30...Control device, 31...Acquisition unit, 32...Injection control unit, 33...Management unit, 34...Intermittent injection control unit, 35...Storage unit, 64...Regulator, 65...First pressure sensor, 67...Flow sensor, 68...Second pressure sensor, 69...Intermittent injection unit, S...Projection material, W...Workpiece.

Claims

1. A spraying method in which a projectile is sprayed onto a workpiece along with a gas, A step of obtaining at least one of the parameters related to acoustic emission, the flow rate of the gas, and the pressure of the gas as the spraying state of the projectile onto the workpiece, A step of managing the supply of the gas by adjusting at least one of the flow rate and pressure of the gas supplied based on the spraying state of the projectile, adjusting the spray time interval in each spray of the projectile based on the spraying state of the projectile, and intermittently spraying the projectile onto the workpiece to reduce the total amount of gas compared to when the projectile is sprayed continuously, A method for spraying a projectile, including the application of a projectile material.

2. The method for spraying a projectile according to claim 1, wherein the spraying step involves adjusting at least one of the flow rate and pressure of the gas supplied based on the spraying state of the projectile, and intermittently spraying the projectile onto the workpiece.

3. The aforementioned acquisition process further acquires the residual stress value required for the workpiece, The method for spraying a projectile according to claim 1 or 2, wherein the spraying step involves adjusting the spraying time interval in each spray of the projectile based on the spraying state of the projectile and the residual stress value, and intermittently spraying the projectile onto the workpiece.

4. The aforementioned acquisition process further acquires surface information relating to the surface condition required for the workpiece, The method for spraying a projectile according to claim 1 or 2, wherein the spraying step involves adjusting the spraying time interval in each spray of the projectile based on the spraying state of the projectile and the surface information, and intermittently spraying the projectile onto the workpiece.

5. A spraying device that sprays a projectile material along with gas onto a workpiece, A measuring device for measuring the state of spraying the projectile onto the workpiece by the spraying device, A control device for controlling the injection device, Equipped with, The control device is An acquisition unit that acquires at least one of the parameters related to acoustic emission, the flow rate of the gas, and the pressure of the gas from the measuring device as the spraying state of the projectile, An injection control unit controls the injection device to manage the supply of the gas by adjusting at least one of the flow rate and pressure of the gas supplied based on the injection state of the projectile, adjust the injection time interval in each injection of the projectile based on the injection state of the projectile, and intermittently inject the projectile onto the workpiece so as to reduce the total amount of gas compared to when the projectile is continuously injected. Having A system for spraying abrasive material.

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