Powder supply system

Abstract

A powder supply system (200) is provided with a hopper (3a), a powder supply machine (21), a pressure adjustment mechanism (22), and an on-off valve (23). The hopper (3a) stores the powder supplied to the film forming device. The powder supply machine (21) is connected to the hopper (3a), and supplies powder into the hopper (3a) while maintaining a constant pressure difference between the powder supply machine (21) and the hopper (3a). The pressure adjusting mechanism (22) can adjust the pressure in the hopper (3a) and the pressure in the powder supply machine (21) so that the pressure in the hopper (3a) and the pressure in the powder supply machine (21) are constant. An on-off valve (23) is provided at a portion connecting the inside of the hopper (3a) and the inside of the powder supply machine (21).

Description

Technical Field

[0001] The present invention relates to a powder supply system. Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2007-75814 (Patent Document 1) discloses a powder supply system for thermal spraying that can replenish powder into a storage container without interrupting the operation of a device to which the powder is supplied.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-75814 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The device disclosed in Japanese Patent Application Publication No. 2007-75814 maintains a minimum required amount of powder in the storage container at all times. This allows for continuous powder supply to the object. However, continuous powder supply to the object can lead to variations in the supply amount over time.

[0008] Furthermore, to ensure that the amount and quality of powder supplied remain stable over time, it is preferable to maintain a constant pressure generated by the gas within the storage container. During spraying, it is difficult to replenish powder from outside the powder supply system. Japanese Patent Application Laid-Open No. 2007-75814 does not consider external powder replenishment from the main container or the pressure within the container.

[0009] The present invention has been made in view of the above-mentioned problems and has an object to provide a powder supply system capable of supplying powder continuously and stably in terms of time.

[0010] Solutions for solving problems

[0011] The powder supply system disclosed herein comprises a hopper, a powder feeder, a pressure adjustment mechanism, and an on-off valve. The hopper stores powder to be supplied to a film-forming device. The powder feeder is connected to the hopper and supplies powder to the hopper while maintaining a constant pressure difference with the hopper. The pressure adjustment mechanism adjusts the pressure within the hopper and the pressure within the powder feeder to maintain a constant pressure within the hopper and the powder feeder. The on-off valve is provided in the portion connecting the hopper and the powder feeder.

[0012] Effects of the Invention

[0013] According to the above, it is possible to provide a powder supply system capable of supplying powder continuously and stably in terms of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram showing the structure of the film forming apparatus according to this embodiment.

[0015] Figure 2 Schematic diagram showing the configuration of the powder supply system according to this embodiment.

[0016] Figure 3 This is a schematic diagram showing a powder replenishing mechanism and a powder container.

[0017] Figure 4 This is a list showing a series of steps and states of each component during powder supply and powder replenishment in the powder supply system of this embodiment. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present disclosure will be described. The same reference numerals are assigned to the same configurations, and their description will not be repeated.

[0019] <Structure of Film Forming Apparatus>

[0020] Figure 1 Schematic diagram showing the structure of the film forming apparatus of this embodiment. Figure 1 The film forming apparatus 100 mainly includes a spray gun 2 including a nozzle 2 b , a powder supply unit 3 , a gas supply unit 4 , and a mask jig 1 .

[0021] The spray gun 2 mainly includes a spray gun body 2a, a nozzle 2b, a heater 2c, and a temperature sensor 9. The nozzle 2b is connected to the front end side, i.e., the first end, of the spray gun body 2a. The pipe 6 is connected to the rear end side, i.e., the second end, of the spray gun body 2a. The pipe 6 is connected to the gas supply unit 4 via a valve 7. The gas supply unit 4 supplies working gas to the spray gun 2 via the pipe 6. By opening and closing the valve 7, the supply state of the working gas from the gas supply unit 4 to the spray gun 2 can be controlled. A pressure sensor 8 is provided on the pipe 6. The pressure sensor 8 measures the pressure of the working gas supplied from the gas supply unit 4 to the pipe 6.

[0022] The working gas supplied from the second end of the spray gun body 2a into the interior of the spray gun body 2a is heated by the heater 2c. The heater 2c is located near the second end of the spray gun body 2a. The working gas flows along arrow 31 within the spray gun body 2a. A temperature sensor 9 is connected to the connection between the nozzle 2b and the spray gun body 2a. The temperature sensor 9 measures the temperature of the working gas flowing within the spray gun body 2a.

[0023] The nozzle 2 b is connected to a pipe 5 . The pipe 5 is connected to a powder supply unit 3 . The powder supply unit 3 supplies powder, which is a film-forming raw material, to the nozzle 2 b of the spray gun 2 via the pipe 5 .

[0024] The mask jig 1 is disposed between the substrate 20 and the spray gun 2. A through hole 1a is formed in the mask jig 1. The through hole 1a defines a film formation region on the surface of the substrate 20.

[0025] <Operation of Film Forming Apparatus>

[0026] exist Figure 1 In the film forming apparatus 100 shown, as indicated by arrow 30, a working gas is supplied from a gas supply portion 4 to the spray gun 2 via a pipe 6. As the working gas, for example, nitrogen, helium, dry air or a mixture thereof can be used. The pressure of the working gas is, for example, about 1 MPa. The flow rate of the working gas is, for example, not less than 300 L / min and not more than 500 L / min. The working gas supplied to the second end of the spray gun main body 2a is heated by a heater 2c. The heating temperature of the working gas is appropriately set according to the composition of the film forming raw material, for example, it can be set to not less than 100°C and not more than 500°C. The working gas flows from the spray gun main body 2a to the nozzle 2b. As indicated by arrow 32, a powder 10 as a film forming raw material is supplied from the powder supply portion 3 to the nozzle 2b via a pipe 5. As the powder 10, for example, aluminum powder is used.

[0027] The powder 10 supplied to the nozzle 2b is ejected from the tip of the nozzle 2b along with the working gas toward the substrate 20. The mask jig 1 is disposed on the surface of the substrate 20. The ejected powder 10 passes through the through-holes 1a of the mask jig 1 and reaches the surface of the substrate 20. A film made of the ejected powder 10 is formed on the surface of the substrate 20.

[0028] <About Powder Supply System>

[0029] Figure 2 Schematic diagram showing the structure of the powder supply system of this embodiment. Figure 2 In order to facilitate the explanation, the mutually orthogonal X direction, Y direction, and Z direction are introduced. The X direction is Figure 2 The left and right directions in the Y direction are Figure 2 The depth direction of the paper. The X direction and the Y direction are Figure 2 The horizontal direction is the Z direction. Figure 2 The up and down direction in is the vertical direction. Figure 2 The powder supply system 200 shown here includes Figure 1 In other words, Figure 1 The area II surrounded by the dotted line of the powder supply part 3 is Figure 2 The powder supply system 200 is a part of the powder supply system 200. The powder supply system 200 is equivalent to Figure 2 The powder supply system 200 includes a hopper 3 a , a powder supply device 21 , a pressure regulating mechanism 22 , and an on-off valve 23 .

[0030] The hopper 3a has a capacity of, for example, 12 liters and can accommodate the powder 10 (see Figure 1 : The same applies hereinafter. The inner wall surface of the hopper 3a may also be inclined with respect to the Z direction. That is, the cross-sectional area perpendicular to the Z direction may be smaller in the region below the upper side of the hopper 3a in the Z direction. This allows the powder supplied to the interior of the hopper 3a to easily move downward.

[0031] The hopper 3a may also include a powder storage portion 3b. The powder storage portion 3b is capable of outputting powder to the outside of the hopper 3a. The powder storage portion 3b is arranged on the lower side of the hopper 3a in the Z direction. The powder storage portion 3b may be integrated with the hopper 3a (part of the same component), or it may be a component different from the hopper 3a. In addition, even if the two are different components, in this specification, the powder storage portion 3b is considered to be a part of the hopper 3a (the powder storage portion 3b is included in the hopper 3a). In any of the above cases, the hopper 3a and the powder storage portion 3b are merged to form Figure 1 The powder supply unit 3 is connected to the inner wall of the hopper 3a and the powder storage unit 3b. Therefore, the powder supply unit 3 as a whole forms a single portion capable of storing powder (the space inside the inner wall). The powder supply unit 3 (the powder storage unit 3b or the portion of the hopper 3a other than the powder storage unit 3b) is connected to the nozzle 2b of the spray gun 2 via a pipe 5. Figure 2 The powder supply unit 3, the pipe 5, and the spray gun 2 are equivalent to Figure 1 The powder supply unit 3, the pipe 5, and the spray gun 2.

[0032] The horizontal dimensions (X and Y directions) of the powder storage section 3b are larger than the horizontal dimensions of the lowest portion of the hopper 3a in the vertical direction (Z direction) excluding the powder storage section 3b. In the powder supply section 3 (hopper 3a), the larger planar surface area of ​​the powder storage section 3b allows for storage in a larger space, allowing the powder in the hopper 3a to flow smoothly downstream (toward the nozzle 2b).

[0033] The powder supply machine 21 is connected to the hopper 3a via, for example, a pipe 5A. The powder supply machine 21 is arranged in the powder supply system 200 upstream of the flow of powder entering and exiting the powder supply unit 3 including the hopper 3a.

[0034] The hopper 3a and the powder supply machine 21 are connected to a pressure adjustment mechanism 22. The pressure adjustment mechanism 22 is capable of adjusting the pressure within the hopper 3a and the pressure within the powder supply machine 21 so that the pressure within the hopper 3a and the pressure within the powder supply machine 21 are constant, for example, unchanged over time. The term "constant pressure" is not strictly limited to a situation where the pressure remains constant over time; it also includes situations where the temporal variation in pressure is within ±10% of the average pressure value. This applies to the following descriptions.

[0035] The pressure regulating mechanism 22 includes a pressure regulating mechanism body 22a (hereinafter referred to as "body 22a") and a pressurizing pipe 22b. The body 22a is the portion that supplies gas such as air (for example, to the hopper 3a). The pressurizing pipe 22b may also be configured with two pipes: one connecting the inside of the body 22a with the inside of the hopper 3a, and the other connecting the inside of the body 22a with the inside of the powder replenisher 21. In other words, the pressure regulating mechanism 22 serves as a gas supply source for the inside of the hopper 3a and the powder replenisher 21.

[0036] The component of the main body 22a connected to the hopper 3a and the component connected to the powder supply machine 21 may be integrated (the same component) or separate (different components). In other words, there may be two main bodies 22a connected to the hopper 3a and the powder supply machine 21, or there may be only one main body 22a.

[0037] like Figure 2 As shown by the arrow F in the figure, gas is supplied (replenished) from the main body 22a via the pressurized pipe 22b to the hopper 3a, and gas is supplied (replenished) to the powder feeder 21. The flow rate of the gas supplied from the main body 22a is adjusted at all times. Through the inflow of gas, the main body 22a controls the pressure in the hopper 3a and the pressure in the powder feeder 21 to be constant and, for example, not changing with time. The pressure regulating mechanism 22 can adjust the pressure in the hopper 3a and the powder feeder 21 by adjusting the flow rate of the transported gas. Specifically, the pressure regulating mechanism 22 can, for example, make the flow rate constant, or increase or decrease the flow rate. The pressure in the powder feeder 21 and the hopper 3a is controlled so that the inflow and outflow of gas are equal, thereby becoming a constant state and not changing with time.

[0038] The on-off valve 23 is provided in the portion connecting the hopper 3a to the powder feeder 21, namely, the pipe 5A. The on-off valve 23 switches between a state in which gas, etc., in the pipe 5A can flow and a state in which gas cannot flow. Specifically, when powder is being replenished from the powder feeder 21 into the hopper 3a, the on-off valve 23 is in an open (connected) state, with the hopper 3a and the powder feeder 21 continuously connected. This state is the first state. Alternatively, when powder is being replenished into the powder feeder 21, the on-off valve 23 is in a disconnected state, with the hopper 3a and the powder feeder 21 disconnected. This state is the second state.

[0039] As described above, the powder supply system 200 is configured in the order of the powder supply machine 21, the piping 5A (on / off valve 23), the hopper 3a (powder supply unit 3), the piping 5, and the nozzle 2b (spray gun 2) from the upstream side to the downstream side of the flow of the powder in and out of the hopper 3a (powder supply unit 3). Figure 2 In the embodiment, the powder is configured to flow from substantially the left side to the right side.

[0040] With the on-off valve 23 open (connected), the powder feeder 21 supplies powder into the hopper 3a. This is achieved by maintaining a constant pressure differential between the hopper 3a and the powder feeder 21 while simultaneously feeding gas-containing powder from the powder feeder 21 into the hopper 3a. The pressure differential mentioned here is not limited to being strictly constant over time; it also encompasses situations where the temporal variation in the pressure differential is within ±10% of the average pressure value in the hopper 3a. This applies to the following.

[0041] When the on-off valve 23 is open (connected), for example, in the first state where gas is flowing through the pipe 5A, the pressure within the hopper 3a and the pressure within the powder replenisher 21 remain constant. Therefore, the pressure difference between the two remains constant. In the first state, the constant pressure value within the powder replenisher 21 is greater than the constant pressure value within the hopper 3a. While maintaining this state, powder flows from the powder replenisher 21 into the hopper 3a via the pipe 5A.

[0042] On the other hand, when the on-off valve 23 is closed (cut off) (for example, the second state where gas does not flow in the pipe 5A), the pressure difference between the powder feeder 21 and the hopper 3a does not need to be the same as the pressure difference in the first state.

[0043] Regardless of the state of the on-off valve 23, gas can also be replenished into the powder supply machine 21 through the pressurized piping 22b. Gas can also be replenished into the hopper 3a through the pressurized piping 22b. Regardless of the state of the on-off valve 23, based on the principle of the spraying process, a negative pressure is generated in the nozzle 2b in a manner lower than that in the hopper 3a. Due to this negative pressure, as shown by the arrow 32, the gas and powder in the hopper 3a flow in a manner introduced into the nozzle 2b side via the piping 5. This gas is used as the film forming device 100 (refer to FIG. Figure 1 ) working gas. Negative pressure is independent of the state of the on-off valve 23 and fluctuates little over time. Therefore, by maintaining a constant pressure value within the hopper 3a, the pressure difference between the nozzle 2b and the hopper 3a remains approximately constant. It is particularly preferable that the pressure value within the hopper 3a be greater than atmospheric pressure. This negative pressure facilitates the flow of gas and powder from the hopper 3a to the nozzle 2b.

[0044] Furthermore, the powder supply system 200 may further include a powder replenishing mechanism 24. The powder replenishing mechanism 24 is a member such as a jig for replenishing powder into the powder supply machine 21.

[0045] Figure 3 This is a schematic diagram showing the powder replenishing mechanism and powder container. Figure 3 In the figure, the up and down direction is also roughly the Z direction. However, in Figure 3 In, it is from Figure 2 Slightly upward squint. Figure 3 The powder replenishing mechanism 24 is a cylindrical member for replenishing powder into the powder supplying machine 21. The powder replenishing mechanism 24 has, for example, a storage portion (space) enclosed by an inner wall surface 24a and a bottom surface of the cylindrical powder replenishing mechanism 24. A bottom protrusion 24b is formed on the bottom surface of the powder replenishing mechanism 24. The bottom protrusion 24b extends upward from the bottom surface in the Z direction and has a hollow cylindrical shape.

[0046] The method of replenishing powder to the powder replenishing machine 21 is as follows. Prepare a powder container 25 that stores the powder to be replenished and has a film, such as aluminum, attached to the upper part as a cover. The powder container 25 is inserted into the storage portion of the powder replenishing mechanism 24 in a state of being turned upside down, and lowered in the storage portion. From the state where the film is in contact with the bottom protrusion 24b, the powder container 25 is further pressed downward. Then, the film is broken by the bottom protrusion 24b. As a result, the powder in the powder container 25 enters the powder replenishing mechanism 24. Of the powder that has entered the powder replenishing mechanism 24, the powder that enters the hollow portion 24c on the inner side of the bottom protrusion 24b falls from the bottom protrusion 24b. For example, by placing the powder replenishing mechanism 24 as Figure 2 The upper area provided in the powder replenisher 21 (or on the upper surface of the powder replenisher 21 ) can replenish the fallen powder into the powder replenisher 21 .

[0047] The powder supply system 200 further includes a vibration mechanism 26. Figure 2 In FIG, the vibration mechanism 26 is arranged outside the powder supply machine 21 . Figure 2 The vibration mechanism 26 is shown as being connected to the bottom of the powder replenishing machine 21 via a connecting member 5B. However, this is not the only embodiment. For example, the vibration mechanism 26 may be connected to a portion of the powder replenishing machine 21 adjacent to the powder replenishing mechanism 24. The vibration mechanism 26 may be located outside the powder replenishing machine 21, but may also be located inside the powder replenishing machine 21. The vibration mechanism 26 may also cause the powder replenishing machine 21 to vibrate. The vibration mechanism 26 is not limited to the main body of the powder replenishing machine 21; it may also cause the powder replenishing mechanism 24 to vibrate.

[0048] The vibration mechanism 26 is a generally known vibrating electronic component. By including the vibration mechanism 26, for example, powder introduced into the powder replenishing mechanism 24 descends within the powder replenishing machine 21 and is smoothly stored therein. Vibrating the powder replenishing mechanism 24 by the vibration mechanism 26 enhances the effect of shaking the powder introduced into the powder replenishing mechanism 24 into the storage area within the powder replenishing machine 21 (replenishing the powder replenishing machine 21).

[0049] like Figure 2 As shown, the hopper 3a (powder supply unit 3) may be installed on an electronic balance 27. The electronic balance 27 measures the amount of powder in the hopper 3a. The electronic balance 27 may also be installed on a trolley 28. In addition, the electronic balance 27 is preferably capable of measuring the remaining amount of powder in the powder supply machine 21.

[0050] Although Figure 2 Although not shown, the powder supply system 200 may also include a pressure gauge capable of measuring the pressure inside the hopper 3 a and the powder replenisher 21 .

[0051] The powder supply system 200 preferably includes a control system 29. When the remaining amount of powder in the powder supply machine 21 decreases during the first state and powder needs to be replenished, the control system 29 automatically closes (shuts off) the on-off valve 23. At this time, the control system 29 controls the powder supply system 200 to minimize the amount and duration of pressure changes in the hopper 3a. Specifically, for example, the amount of gas supplied from the pressure adjustment mechanism 22 to the hopper 3a is temporarily increased. Furthermore, the amount of gas supplied from the pressure adjustment mechanism 22 to the powder supply machine 21 is adjusted to atmospheric pressure to open the powder supply machine 21 to the atmosphere.

[0052] <Background of Action and Effect: Description of Conventional Examples>

[0053] The prior art and its problems that serve as the background for the solution of this embodiment are described again. For example, in the prior art of the first stage, the powder supply system does not have a powder supply machine 21, but only has a Figure 2 The powder supply unit 3 and pressure adjustment mechanism 22 of the hopper 3a are provided. In this case, gas is supplied to the hopper 3a from the pressure adjustment mechanism 22 to maintain a constant pressure in the hopper 3a. From the perspective of utilizing negative pressure to stably supply working gas and powder to the nozzle 2b, the hopper 3a must always be sealed and gas must be supplied to the hopper 3a. However, in this case, the only place where powder can be replenished from the outside is the hopper 3a. Therefore, the hopper 3a must be opened to atmospheric pressure when replenishing powder. In this case, stable supply from the hopper 3a to the nozzle 2b is impossible. In other words, it is difficult to continuously and stably supply powder to the nozzle 2b over time. In addition, for example, when using a hopper 3a with a capacity of 12 liters, the time during which powder can be continuously supplied to the nozzle 2b is approximately 8 hours. There is also a demand to further extend the time during which continuous supply can be achieved.

[0054] Therefore, in the second stage of the prior art, the powder supply system includes a powder replenisher 21 in addition to the hopper 3a. Powder is configured to flow from the powder replenisher 21 to the hopper 3a. In the second stage, the continuous supply period is extended compared to the first stage, for example, to approximately 24 hours. This is because the inclusion of the powder replenisher 21 increases the space available for storing powder and the overall capacity of the device.

[0055] However, in the second stage, it is necessary to supply gas to the powder feeder 21 and the hopper 3a so that the pressure value in the powder feeder 21 is greater than the pressure value in the hopper 3a. Otherwise, the powder cannot flow from the powder feeder 21 to the hopper 3a. In addition, in the second stage, the piping 5A between the powder feeder 21 and the hopper 3a does not have an on-off valve 23. Therefore, the inside of the powder feeder 21 and the hopper 3a are always open (equivalent to the first state). In this case, when replenishing powder in the powder feeder 21, it is still necessary to temporarily open the inside of the hopper 3a to the atmosphere. Therefore, as in the first stage, a stable supply from the hopper 3a to the nozzle 2b cannot be carried out. As a result, for example, the powder in the hopper 3a changes state between its upper side and lower side, which may lead to changes in film thickness and film quality.

[0056] <Effects of this embodiment>

[0057] To address the issues of the above-described conventional example, the powder supply system 200 of this embodiment includes a hopper 3a, a powder supply machine 21, a pressure adjustment mechanism 22, and an on-off valve 23. The hopper 3a stores the powder 10 to be supplied to the film forming apparatus 100. The powder supply machine 21 is connected to the hopper 3a and supplies powder 10 to the hopper 3a while maintaining a constant pressure difference with the inside of the hopper 3a. The pressure adjustment mechanism 22 is capable of adjusting the pressure within the hopper 3a and the pressure within the powder supply machine 21 to maintain a constant pressure within the hopper 3a and the powder supply machine 21. The on-off valve 23 is provided at the portion connecting the inside of the hopper 3a and the inside of the powder supply machine 21.

[0058] In addition to the hopper 3a, a powder feeder 21 is also provided, and an on-off valve 23 is provided at the portion connecting the interior of the hopper 3a to the interior of the powder feeder 21. Therefore, when supplying powder 10, simply closing the on-off valve 23 to enter the second state allows the pressure within the hopper 3a to be maintained at a substantially constant level. This minimizes the effect of negative pressure on the supply of powder 10 from the hopper 3a to the nozzle 2b, minimizing fluctuations in the pressure difference between the hopper 3a and the nozzle 2b. In other words, while maintaining a substantially constant amount of powder 10 supplied to the nozzle 2b, the powder feeder 21 can be simply opened to the atmosphere to supply powder 10 there. This allows for a continuous and stable supply of powder 10 to the nozzle 2b. In other words, a stable amount and quality of powder 10 with minimal error can be continuously supplied over time.

[0059] The pressure regulating mechanism 22 applies a constant pressure higher than that in the hopper 3a to the powder supply device 21. Therefore, the constant pressure difference between the two can be used to maintain a constant flow rate of powder in the pipe 5A. This allows for a continuous and stable supply of powder over time.

[0060] In the powder supply system 200 described above, the on-off valve 23 is in a first state, opening the hopper 3a and the powder supply machine 21 continuously when supplying powder 10 from the powder supply machine 21. When replenishing powder 10 into the powder supply machine 21, the on-off valve 23 is in a second state, shutting off the hopper 3a and the powder supply machine 21. Thus, in the first state, a constant pressure difference is utilized to stably supply powder 10 from the powder supply machine 21 to the hopper 3a in a temporally continuous manner. Furthermore, in the second state, only the inside of the powder supply machine 21 is open to the atmosphere, allowing powder 10 to be stably supplied from the hopper 3a to the nozzle 2b in a temporally continuous manner. In other words, regardless of the state of the on-off valve 23, powder 10 can be stably supplied from the hopper 3a to the nozzle 2b in a temporally continuous manner.

[0061] In the powder supply system 200 described above, the pressure within the hopper 3a remains constant before and after switching between the first and second states. Specifically, the pressure within the hopper 3a remains constant between the first and second states. However, as described above, "constant pressure" includes situations where the temporal variation in pressure is within ±10% of the average value of the pressure. Furthermore, the pressure within the hopper 3a can be maintained at virtually no change when switching from the first state to the second state and vice versa. As described later, the pressure within the hopper 3a may sometimes fluctuate slightly in a very short period of time, but it can also be controlled so that no pressure change occurs at all. Thus, regardless of the state of the on-off valve 23, powder 10 can be stably supplied from the hopper 3a to the nozzle 2b in a temporally continuous manner.

[0062] Regarding the above effects, use the following Figure 4 Make a summary. Figure 4 This is a list showing a series of steps and states of each component during powder supply and powder replenishment in the powder supply system of this embodiment.

[0063] Reference Figure 4 In the first state (S1), the pressure in the powder supply machine 21 is a constant value (for example, P 21 ). The on-off valve 23 is opened (connected). The pressure in the hopper 3a is a certain value (for example, P 3a The gas supply amount F supplied from the pressure regulating mechanism 22 to the hopper 3a (refer to Figure 2 ) is a constant value (e.g., F1). The negative pressure of the nozzle 2b is constant. Since the internal pressure of the hopper 3a and the negative pressure of the nozzle 2b are constant, the difference between them is constant, and the powder 10 can be continuously and stably supplied to the nozzle 2b.

[0064] The amount of powder in the powder feeder 21 is reduced, and the process of switching the on-off valve 23 from the first state to the second state in order to replenish the powder 10 in the powder feeder 21 is (S2). In the process (S2), the inside of the powder feeder 21 is opened to the atmospheric pressure. Therefore, the pressure in the powder feeder 21 changes. Specifically, the gas supplied to the powder feeder 21 is discharged. The on-off valve 23 is switched from the connected (open) state to the disconnected (closed) state. The pressure in the hopper 3a is sometimes higher than P 3a The pressure drop is slightly reduced. This is because the gas supply from the powder supply device 21 is stopped by shutting off the on-off valve 23. Consequently, the gas supply rate F from the pressure regulating mechanism 22 to the hopper 3a increases. Meanwhile, the negative pressure of the nozzle 2b remains substantially constant during step (S2).

[0065] When the powder 10 is replenished in the powder supply machine 21, the second state (S3) is reached. In the second state (S3), the pressure in the powder supply machine 21 is constant (atmospheric pressure). The on-off valve 23 is cut off (closed). The pressure in the hopper 3a is constant (e.g., P 3a The gas supply amount F supplied from the pressure regulating mechanism 22 to the hopper 3a (refer to Figure 2 ) is a constant value (e.g., F2). F2 is greater than F1. From the perspective of maintaining the pressure within the hopper 3a at the same pressure as in the first state, this is to compensate for the amount of gas that was stopped from supplying from the powder feeder 21. The negative pressure of the nozzle 2b is constant. Thus, the pressure difference between the internal pressure of the hopper 3a and the negative pressure of the nozzle 2b is the same as in the first state (S1). Therefore, powder can be supplied to the nozzle 2b in the same manner as in the first state (S1).

[0066] After the powder is replenished (S4), that is, after the powder 10 is replenished to the powder supply machine 21, the period until the powder 10 is replenished to the hopper 3a is as follows. The pressure in the powder supply machine 21 changes. That is, the pressure in the powder supply machine 21 changes. This is because the pressure in the powder supply machine 21 changes in order to return to the constant value P in the first state. 21 , so that a large amount of gas flows into the powder supply machine 21. The on-off valve 23 remains in the cut-off state at this moment. The pressure in the hopper 3a is a certain value (for example, P 3a The gas supply amount F supplied from the pressure regulating mechanism 22 to the hopper 3a (refer to Figure 2 ) is a constant value (for example, F2). The negative pressure of the nozzle 2b is constant.

[0067] After the gas is replenished to the powder, the bulk supply of the powder supply machine 21 is completed, and the pressure in the powder supply machine 21 returns to approximately P 21 After that, the process of switching the on-off valve 23 to the first state is performed again (S5). At this time, as the on-off valve 23 is opened, the gas begins to flow out to the pipe 5A, and the pressure in the powder supply machine 21 sometimes changes instantaneously. However, it immediately returns to a constant value P 21 Since the return is roughly constant, Figure 4 The pressure in the powder supply machine 21 is recorded as "constant P 21 The on-off valve 23 switches from the cut-off (closed) state to the connected (open) state. The pressure in the hopper 3a is sometimes higher than P 3a2a. This is because the connection of the on-off valve 23 resumes the flow of gas from the powder feeder 21 into the hopper 3a. Consequently, the gas supply F from the pressure regulating mechanism 22 to the hopper 3a decreases. Meanwhile, the negative pressure of the nozzle 2b remains roughly constant during step (S2). The negative pressure of the nozzle 2b remains constant during switching of the on-off valve 23 and in both the first and second states. This has been described above.

[0068] As described above, the pressure in the hopper 3a may be lowered to a certain value P in the process of switching the on-off valve (S2, S5). 3a However, as long as the pressure change is completed in the shortest possible time, the pressure in the hopper 3a can be kept constant throughout the entire process.

[0069] Furthermore, the control system 29 may be activated in step (S2) to control the amount of gas supplied to the hopper 3a to be reduced while the amount of gas supplied to the hopper 3a from the pressure regulating mechanism 22 is increased by the amount of reduction. Thus, in step (S2), the powder 10 can be supplied to the nozzle 2b more stably without causing any change in the pressure in the hopper 3a. Similarly, in step (S5), the control system 29 may be activated to control the amount of gas supplied to the hopper 3a to be increased while the amount of gas supplied to the hopper 3a from the pressure regulating mechanism 22 is reduced by the amount of increase. Thus, the performance of the powder supply system 200 is further improved. Consequently, the pressure value in the hopper 3a can be kept constant throughout all steps.

[0070] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. At least two features described in the embodiments disclosed herein may be combined unless there is any conflict.

[0071] Hereinafter, various aspects of the present disclosure are collectively described as supplementary notes.

[0072] (Note 1)

[0073] A powder supply system, comprising:

[0074] a hopper for storing powder supplied to the film forming device;

[0075] a powder supplying device connected to the hopper and supplying the powder into the hopper while maintaining a constant pressure difference with the inside of the hopper;

[0076] a pressure adjustment mechanism capable of adjusting the pressure in the hopper and the pressure in the powder replenisher so as to keep the pressures in the hopper and the powder replenisher constant; and

[0077] An on-off valve is provided at a portion connecting the inside of the hopper and the inside of the powder supply machine.

[0078] (Note 2)

[0079] The powder supply system according to Supplementary Note 1, wherein:

[0080] When the powder is supplied from the powder feeder to the hopper, the on-off valve is in a first state in which the inside of the hopper and the inside of the powder feeder are opened continuously. When the powder is replenished into the powder feeder, the on-off valve is in a second state in which the inside of the hopper and the inside of the powder feeder are cut off.

[0081] (Note 3)

[0082] The powder supply system according to Supplementary Note 2, wherein:

[0083] The pressure in the hopper is constant before and after switching between the first state and the second state.

[0084] (Note 4)

[0085] The powder supply system according to any one of Supplementary Notes 1 to 3, wherein:

[0086] The pressure adjustment mechanism controls the pressure in the hopper and the pressure in the powder replenisher by flowing gas into the hopper and the powder replenisher.

[0087] (Note 5)

[0088] The powder supply system according to any one of Supplementary Notes 1 to 4, wherein:

[0089] The powder supply system further includes a powder replenishing mechanism for replenishing the powder into the powder replenishing machine.

[0090] (Note 6)

[0091] The powder supply system according to Supplementary Note 5, wherein:

[0092] The powder supply system further includes a vibration mechanism for vibrating the powder replenisher.

[0093] (Note 7)

[0094] The powder supply system according to any one of Supplementary Notes 1 to 6, wherein:

[0095] The hopper includes a powder storage portion capable of outputting the powder,

[0096] The powder storage portion has a horizontal dimension greater than a horizontal dimension of a vertically lowermost portion of the hopper excluding the powder storage portion.

[0097] Description of Reference Numerals

[0098] 1. Mask jig; 2. Spray gun; 2a. Spray gun body; 2b. Nozzle; 2c. Heater; 3. Powder supply unit; 3a. Hopper; 3b. Powder storage unit; 4. Gas supply unit; 5. 5A, 6. Piping; 5B. Connecting member; 7. Valve; 8. Pressure sensor; 9. Temperature sensor; 10. Powder; 20. Base material; 21. Powder supply machine; 22. Pressure adjustment mechanism; 22a. Pressure adjustment mechanism body; 22b. Pressurized piping; 23. On-off valve; 24. Powder replenishing mechanism; 24a. Inner wall surface; 24b. Bottom protrusion; 24c. Hollow part; 25. Powder container; 26. Vibration mechanism; 27. Electronic balance; 28. Trolley; 29. ​​Control system; 30. 31. 32. Arrows; 100. Film forming device; 200. Powder supply system.

Claims

1. A powder supply system, wherein: have: a hopper for storing powder supplied to the film forming device; a powder supplying device connected to the hopper and supplying the powder into the hopper while maintaining a constant pressure difference with the inside of the hopper; a pressure adjustment mechanism capable of adjusting the pressure in the hopper and the pressure in the powder replenisher so as to keep the pressures in the hopper and the powder replenisher constant; and An on-off valve is provided at a portion connecting the inside of the hopper and the inside of the powder supply machine.

2. The powder supply system according to claim 1, wherein: When the powder is supplied from the powder feeder to the hopper, the on-off valve is in a first state in which the inside of the hopper and the inside of the powder feeder are opened continuously. When the powder is replenished into the powder feeder, the on-off valve is in a second state in which the inside of the hopper and the inside of the powder feeder are cut off.

3. The powder supply system according to claim 2, wherein: The pressure in the hopper is constant before and after switching between the first state and the second state.

4. The powder supply system according to claim 1 or 2, wherein: The pressure adjustment mechanism controls the pressure in the hopper and the pressure in the powder replenisher by flowing gas into the hopper and the powder replenisher.

5. The powder supply system according to claim 1 or 2, wherein: The powder supply system further includes a powder replenishing mechanism for replenishing the powder into the powder replenishing machine.

6. The powder supply system according to claim 5, wherein: The powder supply system further includes a vibration mechanism for vibrating the powder replenisher.

7. The powder supply system according to claim 1 or 2, wherein: The hopper includes a powder storage portion capable of outputting the powder, The powder storage portion has a horizontal dimension greater than a horizontal dimension of a vertically lowermost portion of the hopper excluding the powder storage portion.

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