Inspection apparatus and inspection method

Abstract

To provide an inspection device excellent in inspection accuracy and inspection efficiency for powder, and to provide an inspection method excellent in inspection accuracy and inspection efficiency for powder.SOLUTION: According to an aspect of the present disclosure, there is provided an inspection apparatus including a mover that moves a conveyance member in a predetermined direction, a powder supplier that supplies powder onto a surface of the conveyance member, a thickness adjuster that is disposed so as to form a gap between the thickness adjuster and the surface of the conveyance member and includes a plate-shaped squeegee that adjusts a thickness of the powder supplied onto the surface of the conveyance member by the powder supplier, a vibrator that vibrates the squeegee, and an inspector that inspects a quality of the powder by emitting inspection light toward the powder whose thickness has been adjusted by the thickness adjuster. The powder satisfies a condition that an angle of repose is 40 ° or more, a frequency in driving the vibration means is 150 Hz or more and 400 Hz or less, and an interval between a surface of a conveying member and a tip of a squeegee when the powder is transferred is 50 μm or more and 250 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inspection device and an inspection method. [Background technology]

[0002] In a conventional device for inspecting the quality of powder, specifically, for example, a device for detecting foreign matter in powder, the powder is supplied from a powder supply unit to the surface of a conveying member, and is transported horizontally, and foreign matter in the powder is detected in an inspection unit. In the inspection unit, the powder is photographed from above using a CCD camera or the like during transportation, and the image data is processed to detect foreign matter.

[0003] In order to reliably detect foreign particles, it is necessary to strictly control the thickness of the powder supplied onto the conveying member. Conventional inspection devices can spread a thin layer of powder onto the conveying member, but this creates unevenness on the powder surface, which can lead to overlooking foreign particles that are thought to be buried in the protrusions.

[0004] Therefore, a technique has been proposed in which a squeegee is used to make the thickness of the powder supplied onto the conveying member uniform.

[0005] For example, Patent Document 1 discloses a powder coating device that includes a squeegee that adjusts the thickness of powder supplied onto a surface of a member by a powder supply unit, and the squeegee vibrates at a frequency of 2 kHz or more and 300 kHz or less.

[0006] Furthermore, Patent Document 2 discloses a powder amount adjustment unit that includes a squeegee and an oscillator that generates a traveling wave that travels from one end of the squeegee to the other end, and that adjusts the amount of powder by leveling the powder supplied onto a substrate.

[0007] However, some types of powder have poor flowability due to their particle shape or mechanical properties. Such powders tend to solidify when a load is applied, even in dry conditions. This can clog the gap between the squeegee and the conveying member, preventing some of the powder from flowing downstream. This reduces the inspection throughput and efficiency. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2021-178271 A [Patent Document 2] Japanese Patent Application Laid-Open No. 2024-33571 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide an inspection device that is excellent in inspection accuracy and inspection efficiency for powder, and to provide an inspection method that is excellent in inspection accuracy and inspection efficiency for powder. [Means for solving the problem]

[0010] These objects can be achieved by the following present inventions (1) to (11). (1) a moving means for moving the conveying member in a predetermined direction; a powder supplying means for supplying powder onto the surface of the conveying member; a thickness adjusting means having a plate-shaped squeegee that is disposed so as to form a gap between itself and the surface of the conveying member and adjusts the thickness of the powder supplied onto the surface of the conveying member by the powder supplying means; a vibration means for applying vibration to the squeegee; an inspection means for irradiating an inspection light onto the powder whose thickness has been adjusted by the thickness adjusting means to inspect the quality of the powder, The powder satisfies the condition that the angle of repose is 40° or more, the vibration frequency during driving of the vibration means is 150 Hz or more and 400 Hz or less, An inspection device characterized in that the distance between the surface of the conveying member and the tip of the squeegee when the powder is being transferred by the moving means is 50 μm or more and 250 μm or less.

[0011] (2) The inspection device according to (1) above, wherein the powder supplying means has a vibration type supplying machine. (3) The inspection device according to (1) or (2) above, wherein the vibration means is an air vibrator.

[0012] (4) The inspection device according to any one of (1) to (3) above, wherein the inspection means receives the inspection light that has passed through the powder and inspects the quality of the powder.

[0013] (5) The inspection device according to any one of (1) to (4) above, wherein the powder satisfies the condition of a degree of compression of 30% or more.

[0014] (6) The inspection device according to any one of (1) to (5) above, wherein the powder is boron nitride.

[0015] (7) a supplying step of supplying powder onto a surface of a conveying member moving in a predetermined direction; a thickness adjusting step of adjusting a thickness of the powder supplied onto the surface of the conveying member by a plate-shaped squeegee while vibrating the squeegee, the plate-shaped squeegee being disposed so as to form a gap between the squeegee and the conveying member; an inspection step of irradiating the powder whose thickness has been adjusted with an inspection light to inspect the quality of the powder, The powder satisfies the condition that the angle of repose is 40° or more, An inspection method characterized in that, in the thickness adjustment process, the vibration frequency of the squeegee is 150 Hz or more and 400 Hz or less, and the distance between the surface of the conveying member and the tip of the squeegee is 50 μm or more and 250 μm or less.

[0016] (8) The inspection method according to (7) above, wherein in the supplying step, the powder is supplied onto the surface of the conveying member using a vibration type supplying machine.

[0017] (9) The inspection method according to (7) or (8) above, wherein the inspection step includes receiving the inspection light that has passed through the powder to inspect the quality of the powder.

[0018] (10) The inspection method according to any one of (7) to (9) above, wherein the powder satisfies the condition of a degree of compression of 30% or more.

[0019] (11) The inspection method according to any one of (7) to (10) above, wherein the powder is boron nitride. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide an inspection device that is excellent in inspection accuracy and inspection efficiency for powder, and to provide an inspection method that is excellent in inspection accuracy and inspection efficiency for powder. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram schematically illustrating an example of the configuration of an inspection device according to the present invention. [Figure 2] FIG. 2 is a diagram showing the powder supplying means portion of the inspection device shown in FIG. 1. [Figure 3] FIG. 2 is a diagram showing the thickness adjusting means portion of the inspection device shown in FIG. 1. [Figure 4] FIG. 2 is a diagram showing an inspection means portion extracted from the inspection device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will be described in detail below. [1] Inspection equipment First, the inspection device of the present invention will be described.

[0023] Fig. 1 is a diagram schematically showing an example of the configuration of an inspection device of the present invention. Fig. 2 is a diagram showing a powder supply means portion extracted from the inspection device shown in Fig. 1. Fig. 3 is a diagram showing a thickness adjustment means portion extracted from the inspection device shown in Fig. 1. Fig. 4 is a diagram showing an inspection means portion extracted from the inspection device shown in Fig. 1.

[0024] The inspection device 1 of the present invention comprises a moving means for moving the conveying member in a predetermined direction, a powder supplying means 110 for supplying powder 2 onto the surface of the conveying member, a thickness adjusting means 120 arranged so as to form a gap with the surface of the conveying member and having a plate-shaped squeegee 121 for adjusting the thickness of the powder 2 supplied onto the surface of the conveying member by the powder supplying means 110, a vibration means 130 for applying vibrations to the squeegee 121, and an inspection means 140 for irradiating inspection light toward the powder 2 whose thickness has been adjusted by the thickness adjusting means 120 to inspect the quality of the powder 2.

[0025] The inspection device 1 of the present invention is characterized in that the powder 2 satisfies the condition that the angle of repose is 40° or more, the vibration frequency when the vibration means 130 is driven is 150 Hz or more and 400 Hz or less, and the distance d between the surface of the conveying member and the tip of the squeegee 121 when the powder 2 is transported by the moving means is 50 μm or more and 250 μm or less.

[0026] With this configuration, it is possible to provide an inspection device 1 that is excellent in inspection accuracy and inspection efficiency for the powder 2.

[0027] Specifically, when adjusting the thickness of the powder 2 using the squeegee 121, a predetermined vibration of the squeegee 121 is transmitted to the powder 2, and the vibration effect reduces the frictional force between the particles that make up the powder 2 (in other words, it becomes less susceptible to frictional resistance due to powder pressure), and the fluidity of the powder 2 is increased, thereby suppressing solidification and clogging of the powder 2 and allowing the layer of the powder 2 (powder layer) to be one in which undesired unevenness and thickness variations are effectively suppressed, thereby improving inspection accuracy and inspection efficiency.

[0028] In the present invention, the "angle of repose" refers to the angle between the free surface of the sediment layer and a horizontal plane when the powder 2 is allowed to fall freely by sinusoidal vibration to form a sediment layer.

[0029] The excellent effects of the present invention can be obtained by the inspection device 1 having the above-mentioned configuration, and cannot be obtained if the inspection device 1 does not have the above-mentioned configuration.

[0030] For example, if the vibration frequency during operation of the vibration means 130 is less than the lower limit, it becomes difficult to sufficiently suppress and level the solidification of the powder 2, and it becomes impossible to sufficiently suppress undesired unevenness and thickness variations in the layer (powder layer) of the powder 2, resulting in poor inspection accuracy.

[0031] Furthermore, if the vibration frequency during driving of the vibration means 130 exceeds the upper limit, the powder 2 is likely to scatter, resulting in a deterioration in inspection accuracy and inspection efficiency.

[0032] Furthermore, if the distance d between the surface of the conveying member and the tip of the squeegee 121 is less than the lower limit, the powder 2 is likely to become clogged in the gap between the surface of the conveying member and the tip of the squeegee 121, resulting in poor inspection accuracy and efficiency.

[0033] Furthermore, if the distance d between the surface of the conveying member and the tip of the squeegee 121 exceeds the upper limit, the thickness of the powder 2 cannot be adjusted to be sufficiently thin, resulting in poor inspection accuracy.

[0034] When the angle of repose of the powder 2 is less than 40°, the powder has high fluidity and does not suffer from the above-mentioned problems of solidification and clogging of the powder 2. The present invention can exert the above-mentioned excellent effects on powder 2 with low fluidity, such as a repose angle of 40° or more. The powder 2 may be any powder that satisfies the condition that the angle of repose is 40° or more.

[0035] The vibration frequency of the vibration means 130 when driven may be 150 Hz or more and 400 Hz or less.

[0036] The distance d between the surface of the conveying member and the tip of the squeegee 121 when the powder 2 is moved by the moving means may be 50 μm or more and 250 μm or less, preferably 75 μm or more and 200 μm or less, and more preferably 100 μm or more and 150 μm or less. This makes it possible to make the above-mentioned effects of the present invention more pronounced.

[0037] The inspection device 1 shown in Figure 1 has a conveyor belt 100 as a transport member for transporting powder 2, and a moving means for moving the conveyor belt 100.Furthermore, from the upstream side to the downstream side of the movement direction of the conveyor belt 100, the inspection device 1 is configured to have a powder supplying means 110, a thickness adjusting means 120, a vibration means 130, an inspection means 140, a foreign matter removing means 160, and a non-defective product recovery section 170 arranged in this order.

[0038] [1-1] Transporting member, moving means The conveying member is a member that conveys the powder 2.

[0039] The conveying member is not particularly limited, but in the example shown in the figure, it is a conveyor belt 100, which is made of a flexible material such as urethane rubber and formed in a seamless circular shape.

[0040] Powder 2 is supplied onto a surface 100a of this conveyor belt 100, and the powder 2 is transported in the horizontal direction.

[0041] Furthermore, the conveyor belt 100 is preferably made of an antistatic material, which can more effectively prevent the powder 2 from flying up due to static electricity, more effectively prevent the powder 2 supplied from the powder supply means 110 from scattering, and transport the powder 2 efficiently and smoothly.

[0042] Furthermore, the conveyor belt 100 is preferably made of a material that can transmit light from an illumination unit 141 of the inspection means 140, which will be described later, and is preferably white and transparent, for example.

[0043] The moving means is a drive unit that moves the transport member in a predetermined direction.

[0044] In the illustrated configuration, a conveyor belt 100 serving as a transport member is wound around a drive roller 101, a plurality of driven rollers 102, and a tension roller 103 serving as moving means, and is configured to circulate in the direction of the arrow in the figure from a powder supplying means 110 to a non-defective product collecting section 170. The conveyor belt 100 is wound around the drive roller 101, the plurality of driven rollers 102, and the tension roller 103 so that at least the portion from the powder supplying means 110 to the foreign matter removing means 160 is horizontal, and as the conveyor belt 100 moves, the powder 2 is transported horizontally.

[0045] In the above description, the conveying member is a circular conveyor belt 100, but this is not limited to this, and the conveying member may be, for example, plate-shaped, sheet-shaped, etc.

[0046] In addition, in this specification, "horizontal," "vertical," "parallel," and "orthogonal" do not mean "horizontal," "vertical," "parallel," and "orthogonal" in the strict mathematical sense, but allow for a slight deviation.

[0047] [1-2] Powder supply means The powder supplying means 110 supplies the powder 2 onto the surface 100 a of the conveyor belt (transport member) 100 .

[0048] The powder supplying means 110 is arranged so as to be able to supply the powder 2 to the upstream surface 100 a of the conveyor belt 100 .

[0049] The powder supplying means 110 is not particularly limited as long as it can supply the powder 2 onto the surface 100a of the conveyor belt (transport member) 100, but it is preferable that it has a vibration type supplying machine.

[0050] This allows the powder 2 to be fluidized by vibration and supplied appropriately onto the conveyor belt 100, and also makes it possible to more effectively prevent the powder 2 from solidifying (blocking) in the area where the squeegee 121 is installed.

[0051] As shown in Figure 2, the vibrating feeder includes, for example, a hopper 111 into which powder 2 is fed, a trough 113 that receives the powder 2 that falls from a nozzle 112 of the hopper 111, and a vibration generator 115 that supports the trough 113 and applies vibrations to the trough 113.

[0052] The hopper 111 has a mortar shape, and has a powder inlet formed at the top, through which the powder 2 is received and held.

[0053] Further, a nozzle 112 is provided at the bottom of the hopper 111. Specifically, the nozzle 112 is provided on the opposite side of the powder inlet, and the powder 2 in the hopper 111 is configured to be discharged from the nozzle 112 so that the discharge amount per unit time becomes a predetermined value.

[0054] The trough 113 receives the powder 2 dropping from the nozzle 112 of the hopper 111. The trough 113 also has a supply groove 114 formed therein for supplying the powder 2 toward the surface 100a of the conveyor belt 100.

[0055] The trough 113 receives vibrations from the vibration generator 115 and transmits the vibrations to the powder 2, thereby discharging the powder 2 to the outside (in other words, supplying it onto the conveyor belt 100).Therefore, the trough 113 is configured to form a supply groove 114 and to allow the powder 2 to move along this supply groove 114.

[0056] The shape of supply groove 114 is not particularly limited as long as it can perform the above-mentioned functions, but it is preferable that supply groove 114 has a flat bottom member 114a and a pair of wall members 114b standing perpendicular to bottom member 114a. In particular, by having bottom member 114a in a flat shape, a stable, constant supply of powder 2 is possible.

[0057] The vibration generator 115 supports the trough 113 and applies vibrations to the trough 113. Specifically, the vibration generator 115 is provided, for example, below the trough 113 and applies vibrations to the trough 113. The vibration applied to the trough 113 is not particularly limited, but vertical vibrations are preferable. Applying vertical vibrations causes the powder 2 to float up from the bottom member 114a, and the vertical width of the vibrations can cause the trough 113 to tilt, making it easier to discharge the powder 2 in a predetermined direction. Furthermore, the discharge amount of the powder 2 (in other words, the amount supplied onto the conveyor belt 100) can be suitably adjusted by adjusting the strength of the vibration.

[0058] The powder supplying means 110 is not limited to the above-mentioned vibrating supplying machine, but may be, for example, a device equipped with a fixed quantity screw feeder that continuously supplies the powder 2 in small amounts, or a device that supplies the powder 2 by allowing it to fall under its own weight.

[0059] Furthermore, the powder supplying means 110 may further include a vibrating sieve. By using the vibrating sieve, relatively large foreign matter contained in the supplied powder 2 can be removed and the powder 2 can be classified.

[0060] [1-3] Thickness adjustment means The thickness adjusting means 120 adjusts the thickness of the powder 2 supplied onto the surface 100 a of the conveyor belt 100 by the powder supplying means 110 .

[0061] As shown in FIG. 3, the thickness adjusting means 120 has a plate-shaped squeegee 121 arranged so as to form a gap of 50 μm or more and 250 μm or less between the surface 100a of the conveyor belt 100 and the thickness adjusting means 120.

[0062] The squeegee 121 makes the thickness of the powder 2 supplied onto the surface 100a of the conveyor belt 100 thin and uniform. In other words, the squeegee 121 adjusts the thickness of the powder 2 supplied onto the surface 100a of the conveyor belt 100 by the powder supplying means 110.

[0063] In the inspection device 1, the powder 2 supplied from the powder supply means 110 onto the surface 100a of the conveyor belt 100 is leveled by the squeegee 121 as the conveyor belt 100 moves until it reaches the inspection means 140.

[0064] The squeegee 121 flattens the powder 2 supplied onto the surface 100a of the conveyor belt 100, thereby forming a layer (powder layer) with a uniform thickness. A predetermined gap is formed between the squeegee 121 and the conveyor belt 100, and the powder 2 supplied onto the surface 100a of the conveyor belt 100 passes through this gap. As a result, the thickness of the powder 2 is adjusted to the distance d between the tip of the squeegee 121 (the portion facing the surface 100a) and the surface 100a of the conveyor belt 100.

[0065] It is preferable that the squeegee 121 is configured to be movable relative to the conveyor belt 100 so that the distance d between the squeegee 121 and the conveyor belt 100 can be changed. This allows the thickness of the transferred powder 2 to be changed as needed.

[0066] The squeegee 121 preferably has a tapered shape that becomes thinner toward the tip.

[0067] This allows the powder 2 supplied onto the surface 100a of the conveyor belt 100 to be more suitably leveled.

[0068] In the squeegee 121, the angle of the tapered portion at the tip is preferably 15° or less, and more preferably 5° or more and 10° or less. This makes it possible to make the above-mentioned effects more pronounced.

[0069] The thickness of the plate-shaped squeegee 121 is preferably 2 mm or more and 4 mm or less. This makes it possible to make the above-mentioned effects more pronounced.

[0070] When the plate-shaped squeegee 121 has a tapered portion, it is preferable that the thickness of the non-tapered portion of the plate-shaped squeegee 121 be within the above-mentioned range.

[0071] The squeegee 121 may be installed not perpendicular to the surface 100a of the conveyor belt 100 but at an angle to the surface 100a of the conveyor belt 100, as shown in Fig. 3. In this case, it is preferable to install the squeegee 121 so that the main surface 121a on the upstream side of the squeegee 121, in other words, the main surface 121a on the side facing the transferred powder 2, forms an acute angle θ with the surface 100a of the conveyor belt 100. This makes it possible to make the above-mentioned effects more pronounced.

[0072] In the squeegee 121, the angle θ that the upstream main surface 121a makes with respect to the surface 100a of the conveyor belt 100 is preferably equal to or greater than 80° and less than 90°. This makes it possible to make the above-mentioned effects even more pronounced.

[0073] [1-4] Vibration means The vibration means 130 applies vibration to the squeegee 121 .

[0074] Specifically, the vibration means 130 applies vibration to the squeegee 121, thereby vibrating the squeegee 121. The vibration means 130 vibrates at a frequency of 150 Hz or more and 400 Hz or less, thereby vibrating the squeegee 121 at a frequency of 150 Hz or more and 400 Hz or less.

[0075] When the vibration of the squeegee 121 is transmitted to the powder 2, the vibration effect reduces the frictional force between the particles that make up the powder 2, increasing the fluidity of the powder 2 and suppressing solidification and clogging of the powder 2.

[0076] In particular, in the present invention, by applying vibrations at a frequency within the above range to powder 2 having an angle of repose of 40° or more, in other words, powder 2 with low fluidity, the fluidity of powder 2 can be more effectively increased.

[0077] This allows the thickness of the powder 2 supplied onto the conveyor belt 100 to be adjusted to be thin and uniform, and also allows the powder 2 to be transported to the downstream side of the squeegee 121 more suitably.

[0078] In order to reliably apply vibration from the vibration means 130 to the squeegee 121, the vibration means 130 and the squeegee 121 must be in contact with each other. The mounting position of the vibration means 130 is not particularly limited.

[0079] For example, the vibration means 130 may be provided near an end portion or near the center portion in the longitudinal direction (depth direction in FIG. 3) of the squeegee 121.

[0080] Furthermore, the vibration means 130 may be attached to the main surface portion of the squeegee 121 or to the side portion thereof, but is preferably attached to the main surface portion of the squeegee 121.

[0081] The number of vibration means 130 is not particularly limited as long as it is one or more. For example, when two vibration means 130 are provided, they may be provided near both ends in the longitudinal direction (depth direction in FIG. 3) of squeegee 121. Furthermore, when three vibration means 130 are provided, they may be provided near the center and both ends in the longitudinal direction (depth direction in FIG. 3) of squeegee 121.

[0082] The vibrating means 130 is not particularly limited as long as it generates vibrations, and examples thereof include an air vibrator that operates using compressed air, an electromagnetic vibrator that applies a pulsating voltage obtained by half-wave rectifying an alternating current to a coil and vibrates a movable iron core with the resulting electromagnetic force, and a motor vibrator that rotates an eccentric plate attached to the rotating shaft of a motor at high speed, but an air vibrator is preferred.

[0083] This allows vibration to be applied to the squeegee 121 more suitably, making the above-mentioned effects more pronounced.

[0084] The vibration direction of vibration means 130, in other words, the vibration direction of squeegee 121, includes at least one of a vertical component and a horizontal component. In other words, squeegee 121 vibrates in at least one of the vertical and horizontal directions.

[0085] The longitudinal direction is a direction parallel to the moving direction of the conveyor belt 100 (MD direction), and the lateral direction is a direction perpendicular to the moving direction of the conveyor belt 100 (TD direction).

[0086] The vibration in the vertical direction is likely to be transmitted as a longitudinal wave to the powder 2, in other words, a wave in the vibration direction approaching and moving away from the squeegee 121 to the powder 2.

[0087] The vertical component has a large effect on reducing the frictional resistance between particles of the powder 2. Since the vertical vibration is a vibration direction in which the squeegee 121 moves toward and away from the powder 2, collisions between particles of the powder 2 are repeated, and the vibration is easily transmitted to the entire powder 2.

[0088] In particular, the vibration component in the vertical direction can move the powder 2 largely in the accumulation portion where the powder 2 tends to accumulate. This makes it easier for the particles of the powder 2 to collide with each other, and the powder 2 is dispersed more suitably.

[0089] The horizontal vibration is easily transmitted as a transverse wave to the powder 2, in other words, a wave in the direction in which the squeegee 121 rubs against the powder 2 and vibrates.

[0090] The magnitude of vibration of the squeegee 121 in the longitudinal direction (MD direction), in other words, the amplitude of the squeegee 121 in the longitudinal direction, is preferably 2 μm or more and 10 μm or less.

[0091] This makes it possible to more suitably reduce the frictional resistance between particles of the powder 2, and further increase the fluidity of the powder 2.

[0092] The magnitude of the vibration of the squeegee 121 in the lateral direction (TD direction), in other words, the amplitude of the squeegee 121 in the lateral direction, is preferably 4 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.

[0093] This makes it possible to more suitably reduce the frictional resistance at the interface between the squeegee 121 and the powder 2, and further increase the fluidity of the powder 2.

[0094] [1-5] Inspection methods The inspection means 140 inspects the quality of the powder 2 by irradiating the powder 2, the thickness of which has been adjusted by the thickness adjusting means 120, with inspection light.

[0095] The quality of the powder 2 may be inspected without any particular limitation, and examples thereof include the presence or absence of foreign matter mixed in the powder 2 and the proportion of foreign matter.

[0096] Examples of the inspection means 140 include one that receives inspection light that has passed through the powder 2 and inspects the quality of the powder 2, and one that receives inspection light that has been reflected by the powder 2 and inspects the quality of the powder 2, but it is preferable that the inspection means 140 receive inspection light that has passed through the powder 2 and inspects the quality of the powder 2.

[0097] This makes it possible to make foreign matter mixed in the powder 2 stand out more clearly on the image, more reliably reducing the number of foreign matters that are overlooked and improving inspection accuracy.

[0098] In particular, since the thickness of the powder 2 is adjusted to be relatively thin and uniform by the thickness adjusting means 120, foreign matter is effectively prevented from being buried in the powder 2, and can be detected more reliably.

[0099] As shown in FIG. 4, the inspection means 140 includes, for example, an illumination unit 141 disposed on the underside of the conveyor belt 100, which irradiates the transported powder 2 with inspection light, and an imaging unit 145 which converts the transmitted light that has passed through the conveyor belt 100 and the powder 2 into a video signal and captures the image.

[0100] Conveyor belt 100 is made of a white transparent material, so that inspection light from illumination unit 141 can be suitably transmitted. The illumination unit 141 includes a light source that irradiates the transferred powder 2 with inspection light.

[0101] The light source may be, for example, an LED or the like that is configured with R (wavelength range of 610 nm to 780 nm), G (wavelength range of 500 nm to 570 nm), and B (wavelength range of 460 nm to 500 nm) and that can independently adjust the brightness of the three RGB wavelength ranges. The form of the light source may be selected as appropriate, such as surface lighting, ring lighting, or spot lighting.

[0102] The imaging unit 145 is composed of, for example, an imaging element using an integrated circuit (IC) that photoelectrically converts transmitted light into a video signal, an optical system that forms an image of the powder 2 on the imaging surface of the solid-state imaging element, and a signal processing circuit that processes the output of the solid-state imaging element to obtain a brightness value for each pixel.

[0103] The imaging element may be, for example, a multiplicity of photodiodes arranged on a planar silicon substrate, and an integrated circuit such as a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) may be used for image transfer.

[0104] A line scan camera can be suitably used as such an imaging unit 145. These imaging units 145 are configured to send image data to the control means 150.

[0105] The number of imaging units 145 to be arranged is not particularly limited, and is determined appropriately depending on the width of the powder 2 to be transported and the resolution of foreign matter detection.

[0106] In the above description, the case where light is irradiated from below the conveyor belt 100 has been described, but light may be irradiated from above the conveyor belt 100. Alternatively, an epi-illumination type may be used in which light is irradiated onto the powder 2 from the same side as the imaging unit 145, and the light (inspection light) reflected by the powder 2 may be received by the imaging unit 145.

[0107] The image data from the imaging unit 145 is sent to the control means 150 . The control means 150 processes the image data to determine the quality of the powder 2, more specifically, for example, the presence or absence of foreign matter, the proportion of foreign matter, and the like.

[0108] [1-6] Foreign matter removal means The inspection device 1 may further include a foreign matter removing means 160 for removing foreign matter that has become mixed in with the powder 2.

[0109] The foreign matter removal means 160 includes, for example, a suction means, and removes foreign matter mixed in with the powder 2 by suction.

[0110] 1, the foreign matter removal means 160 is disposed, for example, between the inspection means 140 and the tension roller 103, and is configured to include a suction pipe 161 arranged in the axial direction above the powder 2 transported by the conveyor belt 100 so as to cross the transport path of the powder 2. The suction pipe 161 has a plurality of slits (not shown) formed along the axial direction. The plurality of slits are arranged approximately evenly in the circumferential and axial directions of the suction pipe 161.

[0111] Although only one suction pipe 161 is shown in FIG. 1, a plurality of suction pipes 161 may be arranged side by side in the direction in which the powder 2 is transferred.

[0112] Furthermore, suction means (not shown) is connected to the suction pipe 161, and the suction means is connected to negative pressure means (not shown) such as a suction pump.

[0113] When the control means 150 analyzes the image data from the imaging unit 145 and determines that a foreign object is present, a predetermined slit in the suction pipe 161 is positioned above the foreign object at the timing when the foreign object is transported to the position of the foreign object removal means 160, depending on the moving speed of the conveyor belt 100, and the foreign object is sucked and removed through the slit.

[0114] The powder 2 from which the foreign matter has been removed by the foreign matter removing means 160, in other words, the non-defective powder 2, is collected in a non-defective product collecting section 170 disposed on the most downstream side of the conveyor belt 100.

[0115] Such an inspection device 1 can achieve excellent inspection accuracy and inspection efficiency for the powder 2. More specifically, solidification and clogging of the powder 2 are suppressed, and undesired irregularities and thickness variations in the layer (powder layer) of the powder 2 are effectively suppressed, thereby improving inspection accuracy and inspection efficiency. Even more specifically, for example, foreign matter is effectively prevented from being buried in convex portions of the layer (powder layer) of the powder 2, effectively preventing foreign matter from being overlooked. Furthermore, smooth transport of the powder 2 downstream of the squeegee 121 increases the inspection throughput and improves inspection efficiency.

[0116] In the above explanation, an example was given in which powder is transported in one direction using a transport member that moves in one direction, but the inspection device of the present invention is not limited to this and can also be applied to an inspection device that transports powder back and forth using a transport member that moves back and forth.

[0117] The powder 2 after inspection obtained in this way, that is, the powder 2 collected in the non-defective product collecting section 170, has foreign matter more reliably removed and is of better quality.

[0118] [2] Powder Next, the powder 2 inspected by the inspection device 1 described above will be described.

[0119] The powder 2 may be any powdery substance that satisfies the condition of an angle of repose of 40° or more, and the raw material, composition, particle shape, etc. are not particularly limited.

[0120] The powder 2 preferably satisfies the condition that the degree of compression is 30% or more. This makes it possible to make the above-mentioned effects of the present invention more pronounced.

[0121] In this specification, the degree of compression (%) is a value calculated by the following formula (1). Compressibility (%) = [1 - {Loose bulk density (g / cm 3 ) / Packed bulk density (g / cm 3 )}〕×100...Equation (1)

[0122] Here, the loose bulk density refers to the density obtained by dividing the mass of the powder 2 by the bulk volume it occupies, and can be determined, for example, by filling a container with air-containing powder 2 by free fall using sinusoidal vibration, and then calculating the mass and the volume of the container. The packed bulk density refers to the density measured after the powder 2 filled in the container for measuring the loose bulk density is packed by tapping.

[0123] The loose bulk density and packed bulk density can be measured by a known method and device such as a powder tester.

[0124] The conditions for the angle of repose and compressibility of the powder 2 as described above are affected by the shape and mechanical properties of the particles that make up the powder 2.

[0125] Examples of powder 2 that meets the above conditions include potato starch, corn starch, sugar, carbon black, calcium stearate, calcium carbonate, cement, iron powder, copper powder, ferrite, melamine resin powder, and boron nitride, with boron nitride being preferred among them.

[0126] Boron nitride is a white powder that is suitable for use as a thermally conductive material (heat dissipation material) in semiconductor substrates, for example. If conductive foreign matter is mixed into this boron nitride, it will impair the insulation reliability of the semiconductor substrate, so more rigorous inspection is required.

[0127] Furthermore, due to its particle shape and mechanical properties, boron nitride does not have good fluidity and tends to solidify when a load is applied, even in dry conditions. Therefore, in the past, there was a problem in that it was prone to clogging when trying to pass through narrow gaps.

[0128] In contrast, the present invention can detect the presence of foreign matter with high accuracy and is suitable for use with powder that tends to solidify when a load is applied. Therefore, by using the inspection device 1 of the present invention to inspect boron nitride, the above-described effects of the present invention can be made even more pronounced.

[0129] Furthermore, powder 2 may contain only one type of powder, or may contain two or more types of powder. When powder 2 is a mixed powder containing multiple types of powder, the dispersion of the multiple types of powder in powder 2 is improved when the powder 2 is flattened by vibrating the squeegee 121. In other words, the multiple types of powder are more easily dispersed in powder 2, and a specific type of powder is less likely to be unevenly layered on the conveyor belt 100.

[0130] This is thought to be because the vibration of the squeegee 121 is transmitted to the areas where the powder 2 is stagnating before reaching the squeegee 121, causing the multiple types of particles that make up the powder 2 to vibrate and flow, thereby allowing the multiple types of particles that make up the powder 2 to mix together favorably and improving dispersibility.

[0131] The average particle size (D50) of the powder 2 is preferably 0.005 μm or more and 50 μm or less.

[0132] This makes it possible to more significantly improve the fluidity of the powder 2 by the vibration of the squeegee 121, thereby making the above-described effects of the present invention more pronounced.

[0133] In this specification, the average particle size (D50) refers to the volume-based median diameter calculated from the particle size distribution measured by a laser diffraction / scattering method, and can be measured using a commercially available laser analysis / scattering particle size distribution measuring device.

[0134] [3] Inspection method Next, the inspection method of the present invention will be described.

[0135] The inspection method of the present invention includes a supply step of supplying powder 2 onto the surface of a conveying member moving in a predetermined direction, a thickness adjustment step of adjusting the thickness of the powder 2 supplied onto the surface of the conveying member by the squeegee 121 while vibrating the plate-shaped squeegee 121 arranged so as to form a gap between the conveying member and the powder 2, and an inspection step of irradiating inspection light onto the powder 2 whose thickness has been adjusted to inspect the quality of the powder 2.

[0136] The inspection method of the present invention is characterized in that the powder 2 satisfies the condition that the angle of repose is 40° or more, the vibration frequency of the squeegee 121 in the thickness adjustment process is 150 Hz or more and 400 Hz or less, and the distance d between the surface of the conveying member and the tip of the squeegee 121 is 50 μm or more and 250 μm or less.

[0137] With this configuration, it is possible to provide an inspection method that is excellent in inspection accuracy and inspection efficiency for the powder 2.

[0138] The inspection method of the present invention can be carried out using, for example, the inspection device 1 of the present invention described above.

[0139] In addition, in the inspection method of the present invention, it is preferable to use the powder 2 as explained in [2] above. This provides the same effect as described above.

[0140] [3-1] Supply process In the supplying step, powder 2 is supplied onto a surface 100a of a conveyor belt (transport member) 100 that moves in a predetermined direction.

[0141] First, powder 2 is supplied onto the upstream surface 100 a of the conveyor belt 100 using the powder supplying means 110 .

[0142] At this time, it is preferable to supply the powder 2 onto the surface 100a of the conveyor belt 100 using a vibration type supplying machine.

[0143] This allows the powder 2 to be fluidized by vibration and supplied appropriately onto the conveyor belt 100, and also makes it possible to more effectively prevent the powder 2 from solidifying (blocking) in the area where the squeegee 121 is installed.

[0144] [3-2] Thickness adjustment process In the thickness adjustment process, a plate-shaped squeegee 121 is arranged so as to form a gap between itself and the conveyor belt 100, and is vibrated at a frequency of 150 Hz or more and 400 Hz or less, while the thickness of the powder 2 supplied onto the surface 100a of the conveyor belt 100 by the squeegee 121 is adjusted to 50 μm or more and 250 μm or less.

[0145] The thickness of the powder 2 supplied to the surface 100a of the conveyor belt 100 is leveled by a squeegee 121 as shown in FIG.

[0146] At this time, by applying a predetermined vibration to the squeegee 121, the vibration of the squeegee 121 is transmitted to the powder 2, and the vibration effect reduces the frictional force between the particles that make up the powder 2, increasing the fluidity of the powder 2, thereby suppressing solidification and clogging of the powder 2.

[0147] This allows the thickness of the layer of powder 2 (powder layer) to be adjusted to be relatively thin and uniform, and also allows the powder 2 to be transported to the downstream side of the squeegee 121 more suitably.

[0148] [3-3] Inspection process In the inspection process, inspection light is irradiated onto the powder 2 whose thickness has been adjusted, and the quality of the powder 2 is inspected.

[0149] The quality of the powder 2 is inspected to see if there is any foreign matter mixed in the powder 2, the proportion of the foreign matter, and so on.

[0150] In the inspection step, it is preferable to receive inspection light that has passed through the powder 2 and inspect the quality of the powder 2.

[0151] This makes it possible to make foreign matter mixed in the powder 2 stand out more clearly on the image, more reliably reducing the number of foreign matters that are overlooked and improving inspection accuracy.

[0152] In particular, since the thickness of the powder 2 is adjusted to be relatively thin and uniform in the thickness adjustment step, foreign matter is effectively prevented from being buried in the powder 2, and can be detected more reliably.

[0153] In the inspection means 140, the imaging unit 145 outputs image data to the control means 150, and the control means 150 processes the image data to determine the presence or absence of foreign matter, the proportion of foreign matter, and the like.

[0154] [3-4] Foreign matter removal process The inspection method of the present invention may further include a foreign matter removal step of removing foreign matter that has become mixed in with the powder 2 if it is determined that foreign matter is present in the inspection step.

[0155] In the foreign matter removal step, foreign matter mixed in with the powder 2 is removed by, for example, suction. Then, the powder 2 from which the foreign matter has been removed as described above, in other words, the non-defective powder 2, is collected in a non-defective product collecting section 170 disposed on the most downstream side of the conveyor belt 100.

[0156] According to this inspection method, it is possible to achieve excellent inspection accuracy and inspection efficiency for the powder 2. More specifically, solidification and clogging of the powder 2 are suppressed, and undesired unevenness and thickness variations in the layer (powder layer) of the powder 2 are effectively suppressed, thereby improving inspection accuracy and inspection efficiency. Even more specifically, for example, foreign matter is effectively prevented from being buried in convex parts of the layer (powder layer) of the powder 2, effectively preventing foreign matter from being overlooked. Furthermore, since the powder 2 can be smoothly transported downstream of the squeegee 121, the inspection throughput increases and inspection efficiency also improves.

[0157] The inspected powder 2 thus obtained has foreign matter more reliably removed, resulting in a powder of superior quality.

[0158] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0159] For example, the inspection device of the present invention may have a configuration other than that described above. Furthermore, each component of the inspection device may be replaced with any component that can perform the same function.

[0160] Furthermore, for example, the inspection method of the present invention may include steps other than those described above. [Explanation of symbols]

[0161] 1: Inspection equipment 2: Powder 100: Conveyor belt 100a: Surface 101: Drive roller 102: driven roller 103: Tension roller 110: Powder supply means 111: Hopper 112: Nozzle 113: Trough 114: Supply groove 114a: Bottom member 114b: Wall component 115: Vibration generator 120: Thickness adjusting means 121: Squeegee 121a: Main surface 130: Vibration means 140: Inspection method 141: Lighting Department 145: Imaging unit 150: Control means 160: Foreign matter removal means 161: Suction pipe 170: Good Product Collection Department d:Spacing θ: Angle

Claims

1. a moving means for moving the conveying member in a predetermined direction; a powder supplying means for supplying powder onto the surface of the conveying member; a thickness adjusting means having a plate-shaped squeegee that is disposed so as to form a gap between itself and the surface of the conveying member and adjusts the thickness of the powder supplied onto the surface of the conveying member by the powder supplying means; a vibration means for applying vibration to the squeegee; an inspection means for irradiating an inspection light onto the powder whose thickness has been adjusted by the thickness adjusting means to inspect the quality of the powder, The powder satisfies the condition that the angle of repose is 40° or more, the vibration frequency during driving of the vibration means is 150 Hz or more and 400 Hz or less, An inspection device characterized in that the distance between the surface of the conveying member and the tip of the squeegee when the powder is being transferred by the moving means is 50 μm or more and 250 μm or less.

2. 2. The inspection device according to claim 1, wherein the powder supplying means comprises a vibrating supplying machine.

3. 3. The inspection device according to claim 1, wherein the vibration means is an air vibrator.

4. 3. The inspection device according to claim 1, wherein the inspection means receives the inspection light that has passed through the powder, and inspects the quality of the powder.

5. 3. The inspection device according to claim 1, wherein the powder satisfies the condition of a degree of compression of 30% or more.

6. 3. The inspection device according to claim 1, wherein the powder is boron nitride.

7. a supplying step of supplying powder onto a surface of a conveying member moving in a predetermined direction; a thickness adjusting step of adjusting a thickness of the powder supplied onto the surface of the conveying member by a plate-shaped squeegee while vibrating the squeegee, the plate-shaped squeegee being disposed so as to form a gap between the squeegee and the conveying member; an inspection step of irradiating the powder whose thickness has been adjusted with an inspection light to inspect the quality of the powder, The powder satisfies the condition that the angle of repose is 40° or more, An inspection method characterized in that, in the thickness adjustment process, the vibration frequency of the squeegee is 150 Hz or more and 400 Hz or less, and the distance between the surface of the conveying member and the tip of the squeegee is 50 μm or more and 250 μm or less.

8. 8. The inspection method according to claim 7, wherein the supplying step supplies the powder onto the surface of the conveying member using a vibration type supplying machine.

9. 9. The inspection method according to claim 7, wherein the inspection step includes receiving the inspection light that has passed through the powder to inspect the quality of the powder.

10. 9. The inspection method according to claim 7, wherein the powder satisfies the condition that the degree of compression is 30% or more.

11. 9. The inspection method according to claim 7, wherein the powder is boron nitride.

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