Foreign matter removing device

Abstract

The purpose of the present invention is to provide a foreign matter removal device which is effective even with respect to highly adhesive powder. Therefore, this foreign matter removal device is provided with: a substrate on which a powder is disposed; and a classification unit that classifies the powder to be recovered and the foreign particles to be removed. The grading part is provided with a grading net; an excitation unit that vibrates the substrate and / or the classification net; and a pressing part which presses the classification net against the powder. Thus, by pressing the mesh against the powder and vibrating the powder, it is possible to classify the powder while crushing agglomerates of the powder, and thus it is possible to remove foreign matter even for highly adhesive powder.

Description

Technical Field

[0001] The present invention relates to a foreign matter removing device for removing foreign matter particles mixed in powder. Background Art

[0002] As a technique for removing foreign matter particles mixed in powder, Patent Document 1 is known. In Patent Document 1, a foreign matter removing method is described in which vibration is applied to powder to form a thin layer, foreign matter particles are exposed on the surface, and the surface of the powder layer is photographed to detect foreign matter.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-333365 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In the case of powder with strong adhesiveness, agglomerates may be formed due to the adhesion force between particles. However, it is not always possible to break the agglomerates only by applying vibration to the powder. Therefore, in the technique described in Patent Document 1, when foreign matter particles are mixed in the agglomerates, the foreign matter particles may not be exposed on the surface, making it difficult to detect the foreign matter.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a foreign matter removing device that is also effective for powder with strong adhesiveness.

[0009] Means for Solving the Problems

[0010] To solve the above problems, the foreign matter removing device of the present invention includes: a substrate on which powder is disposed; a classification unit that classifies the powder to be recovered and foreign matter particles to be removed, the classification unit having: a classification mesh; an exciting unit that vibrates the substrate and / or the classification mesh; and a pressing unit that presses the classification mesh against the powder.

[0011] Advantages of the Invention

[0012] According to the present invention, by pressing the mesh against the powder and vibrating it, it is possible to classify while breaking the agglomerates of the powder, so that foreign matter can be removed even from powder with strong adhesiveness.

[0013] Problems, configurations, and effects other than the above will be clarified by the following description of the mode for carrying out the invention. Brief Description of the Drawings

[0014] Figure 1 It is a plan view showing a schematic configuration of the foreign matter removing device according to Embodiment 1.

[0015] Figure 2 is a cross-sectional view showing the structure of the classification unit in Embodiment 1 ( Figure 1 A-A cross-sectional view).

[0016] Figure 3A is a cross-sectional view showing the classification process of Embodiment 1.

[0017] Figure 3B is a cross-sectional view showing the recovery process of Embodiment 1.

[0018] Figure 4 is a cross-sectional view showing the structure of the photographing unit in Embodiment 1 ( Figure 1 B-B cross-sectional view).

[0019] Figure 5 is a cross-sectional view showing the structure of the classification unit in Embodiment 2.

[0020] Figure 6 is a cross-sectional view showing the structure of the classification unit in Embodiment 3.

[0021] Figure 7 is a top view showing the schematic structure of the foreign matter removing device of Embodiment 4.

[0022] Figure 8 is a cross-sectional view showing the structure of the primary classification unit 51 in Embodiment 4. Detailed Embodiment

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments are used to illustrate the present invention, and for the sake of clarity of explanation, appropriate omissions and simplifications are made. The present invention can also be implemented in various other ways. Unless otherwise specified, each component can be single or multiple.

[0024] For ease of understanding of the invention, the positions, sizes, shapes, ranges, etc. of the respective components shown in the drawings sometimes do not represent the actual positions, sizes, shapes, ranges, etc. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, ranges, etc. disclosed in the drawings.

[0025] When there are multiple components having the same or similar functions, sometimes different suffixes are added to the same reference numerals for explanation. In addition, when it is not necessary to distinguish these multiple components, sometimes the suffixes are omitted for explanation.

[0026] Embodiment 1

[0027] Based on Figures 1 to 4 Embodiment 1 will be described. Figure 1 is a top view showing the schematic structure of the foreign matter removing device of Embodiment 1. AsFigure 1 As shown in Figure 1 , the foreign matter removing device 1 includes a turntable 2, a feeder 4, a classification unit 5, a photographing unit 6, a qualified product recovery unit 7, a defective product recovery unit 8, and a control unit (not shown). In addition, the feeder 4, the classification unit 5, the photographing unit 6, the qualified product recovery unit 7, and the defective product recovery unit 8 are located at different positions from the upstream side to the downstream side in the rotation direction of the turntable 2.

[0028] A groove portion 3 is formed on a part of the upper surface of the turntable 2, and powder is supplied to the groove portion 3 through the feeder 4. In order to obtain sufficient strength and rigidity, the material of the turntable 2 is preferably stainless steel or aluminum. However, in the case where it is not desired to mix metal foreign matter into the powder, it is preferable to form a resin coating such as fluororesin or a non-metal layer such as DLC coating on the surface of the groove portion 3 or the entire surface of the turntable 2. The depth of the groove portion 3 is set to be approximately the same as or less than the lower limit value of the size of the foreign matter particles to be removed.

[0029] The classification unit 5 classifies the powder to be recovered and the foreign matter particles to be removed. Specifically, the foreign matter particles are exposed to the surface from the powder layer supplied to the groove portion 3. Figure 2 is a cross-sectional view showing the structure of the classification unit in Example 1 ( Figure 1 A - A cross-sectional view). The classification unit 5 includes: a net housing 9, a classification net 10, a space forming portion (space forming net 11), a pressing portion (net pressing plate 12), a suction mechanism (pump 13), a first vibration portion (base 16, vibrator 18), a second vibration portion (vibrator 20), a first lifting mechanism 14, and a second lifting mechanism 19.

[0030] In the net housing 9, the classification net 10, the space forming net 11, and the net pressing plate 12 are sequentially installed from the powder side (lower side). The classification net 10 uses a mesh that is approximately the same as or less than the lower limit value of the size of the foreign matter particles to be removed and larger than the median particle size of the powder. Here, even if the mesh of the classification net 10 is larger than the size of the foreign matter particles, as long as it is slightly larger, substantial removal of the foreign matter particles can be performed and the throughput can be increased. However, setting it to be below the size of the foreign matter particles enables reliable removal and improves the reliability. The space forming net 11 is provided between the classification net 10 and the net pressing plate 12. It is a net with a thickness using thick wires and forms a plurality of spaces for accommodating the powder that has passed through the classification net 10. The horizontal cross-sectional area of each space of the space forming net 11 is larger than the cross-sectional area of each opening of the classification net 10. That is, the mesh of the space forming net 11 is larger than the mesh of the classification net 10. In addition, according to the volume of the powder passing through the classification net 10, multiple sheets of the space forming net 11 can be overlapped and provided. The net pressing plate 12 is used to flatten the shape of the net when pressing the classification net 10 against the powder via the space forming net 11, and a plurality of vertically penetrating openings for sucking the powder are provided on a plate with high rigidity.

[0031] When it is not desired to mix metal foreign substances into the powder, resin meshes such as nylon are preferably used as the materials for the classification mesh 10 and the space forming mesh 11. The mesh pressing plate 12 and the mesh housing 9 are also preferably formed of resin, but in the case where sufficient rigidity cannot be obtained, they may be formed of metals such as stainless steel and aluminum. In this case, a non-metallic layer such as a resin coating of fluororesin or a DLC coating is preferably formed on the portion in contact with the powder.

[0032] The mesh housing 9 is mounted on the first lifting mechanism 14, and the classification mesh 10 can be moved closer to or farther away from the powder. When pressing the classification mesh 10 against the powder, the control unit controls the first lifting mechanism 14 to adjust the height of the mesh housing 9 so as to follow the reduction in the powder layer thickness accompanying the passage of the powder through the classification mesh 10. For the reduction in the powder layer thickness generated during classification, the mesh housing 9 can also be made to follow by using an elastic member such as a spring. In addition, a pump 13 for sucking the powder through the opening of the mesh pressing plate 12 is connected to the mesh housing 9.

[0033] Below the turntable 2, in addition to the second lifting mechanism 19, as the first exciting unit for vibrating the turntable 2, a base 16 and an oscillator 18 are provided. The base 16 is formed of a metal such as aluminum or stainless steel and can be given vibration by the oscillator 18 fixed to its lower side. In addition, the base 16 is mounted on the second lifting mechanism 19 and can approach or move away from the lower surface of the turntable 2. When it is not desired to mix metal foreign substances into the powder, it is preferable to paste a resin sheet such as fluororesin on the upper surface of the base 16 to suppress the generation of metal particles caused by friction with the turntable 2.

[0034] Use Figure 3A And Figure 3B The operation in the classification unit 5 will be described. Figure 3A is a cross-sectional view showing the classification process of Example 1, Figure 3B is a cross-sectional view showing the recovery process of Example 1. In this embodiment, the following series of processes are repeated, in which the turntable 2 stops after rotating a predetermined angle, and after performing the Figure 3A shown classification process and Figure 3B shown recovery process, the turntable 2 rotates again.

[0035] First, the classification process will be described. In a state where the control unit stops the turntable 2, it controls the first lifting mechanism 14 to press the mesh pressing plate 12 and the classification mesh 10 together with the mesh housing 9 against the turntable 2 and the powder. At this time, the control unit controls the second lifting mechanism 19 to press the base 16 against the turntable 2. And the control unit controls the oscillator 18 to vibrate the turntable 2 via the base 16 in a state where the lower surface of the classification mesh 10 is approximately at the same height as the upper surface (excluding the groove portion 3) of the turntable 2. As a result, the powder is fluidized, and particles smaller than the mesh size of the classification mesh 10 pass through the classification mesh 10.

[0036] By pressing the powder while applying vibration, even for powders with strong adhesiveness, the agglomerates can be broken and the powder can be fluidized. At this time, if the control unit uses the vibrator 20 as the second excitation unit to vibrate the classification mesh 10 together with the mesh housing 9, the fluidization is further promoted, the flow rate of the powder passing through the classification mesh 10 becomes faster, and the throughput can be increased.

[0037] Next, the recovery process will be described. In a state where the turntable 2 is stopped, the control unit controls the first lifting mechanism 14 to separate the mesh pressing plate 12 and the classification mesh 10 together with the mesh housing 9 from the turntable 2 and the powder. At this time, the control unit controls the second lifting mechanism 19 to separate the base 16 from the turntable 2. Further, in a state where the classification mesh 10 is separated from the powder, the control unit drives the pump 13 to suck the powder that has passed through the classification mesh 10. Since the sucked powder does not contain foreign particles, it is recovered as a qualified product in the qualified product recovery unit 7. In addition, when the pump 13 sucks the powder, the mesh housing 9 can be vibrated by the vibrator 20 to easily suck the powder clogged in the mesh holes. Here, as described above, the depth of the groove portion 3 is set to be the same as or less than the size of the foreign particles to be removed, so the distance from the powder placement surface (the bottom surface of the groove portion 3) of the turntable 2 to the lower surface of the classification mesh 10 during the classification process is also the same as or less than the size of the foreign particles.

[0038] Therefore, after the classification process, the layer thickness of the powder remaining on the turntable 2 is approximately the same as the depth of the groove portion 3, and at least a part of the foreign particles to be removed is exposed on the surface of the powder layer.

[0039] The residue remaining on the turntable 2 after the classification process and the recovery process is sent to the imaging unit 6 by the rotation of the turntable 2. After that, based on the captured image of the imaging unit 6, it is determined whether the residue contains foreign particles. Assuming that foreign particles are included in the powder layer, as described above, the foreign particles are exposed on the surface of the powder layer, so the foreign particles can be captured by the captured image.

[0040] Figure 4 is a cross-sectional view showing the structure of the imaging unit in Embodiment 1 ( Figure 1 sectional view taken along line B-B).

[0041] As Figure 4As shown, the photographing unit 6 includes an illumination unit 21, a lens 22, a CCD 23, and an image processing unit 24. The illumination unit 21 irradiates light onto the powder from the side of the photographing unit 6, for example, a ring-shaped illumination is used. The lens 22 is mounted on the CCD 23, and an image of the powder surface is acquired by the CCD 23 at an appropriate magnification. The acquired image is analyzed in the image processing unit 24 to determine whether there are foreign particles. As a method for discriminating foreign particles, for example, there are methods using differences in particle shape, light intensity of reflected / scattered light, chromaticity differences, etc. In addition, the discrimination of foreign particles may not be performed by the image processing unit 24 but by the control unit.

[0042] The powder for which it is determined whether there are foreign particles in the photographing unit 6 is sent to the acceptable product recovery unit 7 or the non-acceptable product recovery unit 8 through the rotating table 2. Pumps 13 are connected to the acceptable product recovery unit 7 and the non-acceptable product recovery unit 8 to recover the powder sucked by the pumps 13. The powder determined to have "no" foreign particles is recovered into the acceptable product recovery unit 7, and the powder determined to have "yes" foreign particles is recovered into the non-acceptable product recovery unit 8.

[0043] As described above, according to the present embodiment, by pressing the mesh against the powder and vibrating it, it is possible to classify while crushing the agglomerates of the powder. Therefore, even for powders with strong adhesiveness, foreign particles can be exposed on the surface, and as a result, it is possible to discriminate and remove foreign particles contained in the powder.

[0044] In addition, in the present embodiment, it is configured to dispose the powder on the rotating table 2 and move the position of the powder by rotating the rotating table 2, but it may also be configured to move the position of the powder by linearly moving the powder through another substrate such as a conveyor instead of the rotating table 2. In addition, in the present embodiment, the agglomerates of the powder are mainly crushed by the vibration imparted to the powder by the first vibration unit via the rotating table 2, but the agglomerates of the powder may also be crushed only by the vibration imparted to the powder by the second vibration unit. In addition, in the present embodiment, by performing the recovery process after the classification process, it is possible to perform highly reliable classification and recovery. However, when there is a gap between the mesh housing 9 and the rotating table 2 during the classification process and suction is possible, the throughput can also be increased by performing the classification process and the recovery process simultaneously.

[0045] Embodiment 2

[0046] Based on Figure 5 An explanation will be given of Embodiment 2. Figure 5 It is a cross-sectional view showing the structure of the classification unit in Embodiment 2. In Embodiment 2, while conveying the powder in the horizontal direction, the classification mesh 25 is also moved along the conveying direction of the powder, so that the classification can be continuously performed without stopping the rotation of the rotating table 2, thereby increasing the throughput. The overall structure of the foreign matter removing device in Embodiment 2 is the same as that of Figure 1It is the same as Embodiment 1 shown, but the structure of the classification section 5 of Embodiment 2 is different from that of Embodiment 1. Hereinafter, the structure of the classification section 5 of Embodiment 2 will be specifically described.

[0047] As Figure 5 shown, the classification section 5 of Embodiment 2 includes a classification net 25, a space forming section (space forming sheet 26), a pressing section (base 30, roller 32), a recovery section 27, a turning roller 28, a first excitation section (base 34, oscillator 35, roller 36), a second excitation section (oscillator 31), a third excitation section (base 40, oscillator 39, roller 41), and a support 37.

[0048] The classification net 25 and the space forming sheet 26 are moved by the turning roller 28 in synchronization with the conveyance of the rotary table 2. Here, since the powder rotates together with the rotary table 2, the speed of the powder on the outer diameter side is greater than the speed of the powder on the inner diameter side. On the other hand, the classification net 25 moves in a circular motion at a constant speed along the tangent direction of the rotary table 2. Assuming that the moving speed of the classification net 25 is the same as the speed of the powder on the inner diameter side, the speed of the classification net 25 is too slow, and the powder is likely to accumulate on the upstream side. On the contrary, if the moving speed of the classification net 25 is the same as the speed of the powder on the outer diameter side, the speed of the classification net 25 is too fast, which may cause the surface of the powder layer to be disordered or the powder to be ejected. Therefore, in the present embodiment, the moving speed of the classification net 25 is made to be a speed greater than the speed of the powder on the inner diameter side and less than the speed of the powder on the outer peripheral side, and preferably a speed in the middle of the speed of the powder at the innermost diameter and the speed of the powder at the outermost diameter. Thereby, the speed difference between the classification net 25 and the powder can be suppressed, and the reliability of the device can be improved. Furthermore, if the diameter of the rotary table 2 is made sufficiently larger than the width of the powder layer, the speed difference between the classification net 25 and the powder is further suppressed, and the reliability is further improved.

[0049] The classification net 25 uses a mesh that is of the same degree or less than the lower limit value of the size of the foreign matter particles to be removed and larger than the median particle size of the powder. The space forming sheet 26 is formed by fixing a mesh having a thickness to an unperforated sheet using a thick wire diameter wire, and is provided inside the classification net 25 (opposite side of the rotary table). In addition, the mesh of the space forming sheet 26 is larger than the mesh of the classification net 25, and the space forming sheet 26 has a plurality of spaces for accommodating the powder that has passed through the classification net 25. Since the space forming sheet 26 uses an unperforated sheet, it is possible to prevent the powder from mixing into the structures located inside the space forming sheet 26, that is, the pressing section, the turning roller 28, the second excitation section, and the third excitation section. In addition, according to the volume of the powder passing through the classification net 25, multiple sheets of the mesh of the space forming sheet 26 may be overlapped and provided. When it is not desired to mix metal foreign matter into the powder, as the material of the classification net 25 and the space forming sheet 26, it is preferable to use a resin mesh such as nylon or fluororesin.

[0050] The pressing part presses the classification net 25 and the space forming sheet 26 against the powder on the rotating table 2, imparts vibration to the powder on the rotating table 2, and includes a base 30 and a roller 32. The base 30 is supported by an elastic member such as a spring to apply a constant pressing force to the classification net 25 and the space forming sheet 26. The roller 32 is fixed to the base 30 and freely rotates following the movement of the space forming sheet 26. In addition, an oscillator 31 as the second exciting part is also fixed to the base 30, and the vibration is transmitted from the oscillator 31 to the roller 32.

[0051] The first exciting part is used to vibrate the rotating table 2 and includes a base 34, an oscillator 35, and a roller 36. The base 34 is formed of metal or the like and can apply vibration through the oscillator 35 fixed to its lower side. The roller 36 is fixed to the upper side of the base 34, is transmitted the vibration from the oscillator 35, and freely rotates following the movement of the rotating table 2. In addition, below the rotating table 2, a support 37 is provided in addition to the first exciting part. The support 37 is constituted by an elastic member such as a spring to apply a constant pressing force to the rotating table 2.

[0052] The third exciting part is used to peel off the powder adhering to the space forming sheet 26 through the classification net 25 and includes a base 40, an oscillator 39, and a roller 41. The oscillator 39 and the roller 41 are fixed to the base 40, and the vibration is transmitted from the oscillator 39 to the roller 41. The roller 41 freely rotates following the movement of the space forming sheet 26.

[0053] The recovery part 27 recovers the powder that has passed through the classification net 25. Since the recovered powder does not contain the foreign matter particles to be removed, it is used as a qualified product. In addition, when the recovery part 27 recovers the powder, for example, suction based on a pump (not shown) is performed.

[0054] According to this embodiment, it is possible to continuously classify the surface of the powder layer while the rotating table 2 is rotating, so the throughput is further improved. In addition, vibration is applied to the rotating rotating table 2 via the roller 36, and a pressing force is applied to the moving classification net 25 and the space forming sheet 26 via the roller 32, so wear at the contact surface can also be suppressed.

[0055] According to the layout around the installation location of the foreign matter removal device, a structure in which another substrate such as a conveyor moves linearly can also be adopted instead of the rotating table 2. In this case, the speed difference between the classification net 25 and the powder can be eliminated, and the reliability can be improved. And in this embodiment, a structure in which the classification net 25 circulates in a ring shape is taken as an example for description, but the classification net 25 can also be composed of roll-to-roll, and the rolls can be replaced regularly.

[0056] Embodiment 3

[0057] Based on Figure 6 Embodiment 3 will be described.Figure 6 This is a cross-sectional view showing the structure of the classification unit in Embodiment 3. In Embodiment 2, since the vibration generated by the oscillator is transmitted to the roller via the base and the vibration is applied from the roller to the turntable 2 and the classification net 25, attenuation of vibration energy cannot be avoided. Therefore, in Embodiment 3, the roller is not used, and the turntable 2 etc. are made to slide by using the low-friction layer formed on the surface of the base, suppressing the attenuation of vibration energy. The overall structure of the foreign matter removing device in Embodiment 3 is the same as that in Embodiment 1 and Embodiment 2, but the structure of the classification unit 5 in Embodiment 3 is different from each embodiment. Hereinafter, the structure of the classification unit 5 in Embodiment 3 will be specifically described.

[0058] As Figure 6 shown, the classification unit in Embodiment 3 includes a classification net 25, a space forming unit (space forming piece 26), a pressing unit (base 43), a recovery unit 27, a turning roller 28, a first excitation unit (base 47, oscillator 48), a second excitation unit (oscillator 44), a third excitation unit (base 40, oscillator 39, roller 41), and a support 50. The structures of the classification net 25, the space forming unit, the recovery unit 27, the turning roller 28, the second excitation unit, and the third excitation unit are the same as those in Embodiment 2.

[0059] The pressing unit in Embodiment 3 presses the classification net 25 and the space forming piece 26 against the powder on the turntable 2 in the same manner as in Embodiment 2, imparts vibration to the powder on the turntable 2, and includes a base 43. However, different from Embodiment 2, it does not include a roller. However, a low-friction layer 45 is formed on the lower surface of the base 43 in Embodiment 3, that is, the surface in contact with the space forming piece 26. The base 43 slides relative to the space forming piece 26 with low friction. For example, a resin sheet such as fluororesin or high-density polyethylene is pasted on the base 43, or the base 43 is coated with fluororesin, DLC, etc., or the surface of the base 43 is made uneven by electroplating, sandblasting, etc.

[0060] The first excitation unit in Embodiment 3 vibrates the turntable 2 in the same manner as in Embodiment 2, and includes a base 47 and an oscillator 48. However, different from Embodiment 2, it does not include a roller. However, a low-friction layer 49 is formed on the upper surface of the base 47 in Embodiment 3, that is, the surface in contact with the turntable 2. The low-friction layer 49 slides relative to the turntable 2 with low friction. For example, a resin sheet such as fluororesin or high-density polyethylene is pasted on the base 47, or the base 47 is coated with fluororesin, DLC, etc., or the surface of the base 47 is made uneven by electroplating, sandblasting, etc.

[0061] According to this embodiment, it is possible to suppress the attenuation of vibration energy and apply vibration to the powder. In addition, it is possible to press the rotary table 2 and the space forming sheet 26 over the entire surface of the base, which can further improve the throughput of classification. Further, in this embodiment, a low friction layer 49 is formed on the upper surface of the base 47 of the first excitation unit, but a low friction layer may also be formed on the lower surface of the rotary table 2. Additionally, in this embodiment, the third excitation unit uses the roller 41, but a low friction layer or the like may be formed on the base 40 instead of the roller 41.

[0062] Embodiment 4

[0063] Based on Figure 7 and Figure 8 Embodiment 4 will be described. In Embodiments 1 to 3, all of the powder to be inspected is supplied to the rotary table 2, and classification of the powder surface and imaging are performed. However, for example, if the foreign matter particles to be detected become smaller, it is necessary to reduce the field of view and increase the imaging resolution, so there is a case where the imaging throughput cannot meet the required amount. Therefore, in this embodiment, by performing classification once before supplying the powder to the rotary table 2, the amount of powder required for imaging is reduced, and the inspection throughput is increased.

[0064] Figure 7 is a top view showing a schematic structure of the foreign matter removal device of Embodiment 4. As Figure 7 shown, the foreign matter removal device 1 includes a rotary table 2, a feeder 4, a classification unit 5, an imaging unit 6, a qualified product recovery unit 7, a non-conforming product recovery unit 8, a control unit (not shown), and a primary classification unit 51. The classification unit 5 is located upstream of the imaging unit 6, the feeder 4 is located upstream of the classification unit 5, and the primary classification unit 51, which is another classification unit, is located upstream of the feeder 4. The structures other than the primary classification unit 51 are the same as those in Embodiment 1. The primary classification unit 51 separates the powder into powder without foreign matter and powder containing foreign matter before supplying the powder to the rotary table 2 via the feeder 4. The powder without foreign matter is recovered as a qualified product, and the powder containing foreign matter is supplied to the feeder 4.

[0065] Figure 8 is a cross-sectional view showing the structure of the primary classification unit 51 in Embodiment 4. The primary classification unit 51 includes a feeder 59, a net housing 52, a classification net 53, a space forming unit (space forming net 54), a pressing unit (net pressing plate 55), a suction mechanism (pump 58), a powder conveying sheet 60, a turning roller 70, a first excitation unit (base 62, vibrator 65), a second excitation unit (vibrator 56), a third excitation unit (base 68, vibrator 67, roller 69), a first lifting mechanism 57, and a second lifting mechanism 64.

[0066] The feeder 59 quantitatively supplies powder onto the powder conveying sheet 60. The powder conveying sheet 60 is configured in a ring shape and conveys the powder while circulating and moving through the turning rollers 70. When it is not desired to mix metal foreign matters into the powder, as the material of the powder conveying sheet 60, resin materials such as fluororesin are preferably used.

[0067] In the mesh housing 52, a classification mesh 53, a space-forming mesh 54, and a mesh pressing plate 55 are sequentially installed from the powder side (lower side). The structures of the classification mesh 53, the space-forming mesh 54, and the mesh pressing plate 55 are the same as those of the classification mesh 10, the space-forming mesh 11, and the mesh pressing plate 12 in the first embodiment.

[0068] The basic structures of the pump 58, the first excitation unit, the second excitation unit, the first lifting mechanism 57, and the second lifting mechanism 64 are also the same as those of the pump 13, the first excitation unit, the second excitation unit, the first lifting mechanism 14, and the second lifting mechanism 19 in the first embodiment. The third excitation unit is used to peel off the powder adhering to the powder conveying sheet 60, and its structure is basically the same as that of the third excitation unit in the second embodiment.

[0069] In this embodiment, the following series of processes are repeated, in which the powder conveying sheet 60 stops after moving a predetermined amount, and after performing the classification process and the recovery process, the powder conveying sheet 60 moves again. In addition, the specific operations in the classification process and the recovery process are basically the same as the operations described in Figure 3A and Figure 3B the first embodiment. However, in this embodiment, the powder remaining on the powder conveying sheet 60 after the recovery process is discharged from the primary classification unit 51 and supplied to the feeder 4.

[0070] According to this embodiment, by performing primary classification in advance before supplying the powder to the turntable 2, the throughput of the entire device can be improved.

[0071] The foregoing embodiments are examples described in detail for easily understanding the present invention and are not limited to having all the structures described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of another embodiment, or the structure of another embodiment can be added to the structure of a certain embodiment. For example, in the fourth embodiment, the same classification unit 5 as in the first embodiment is used, but the classification unit 5 the same as in the second embodiment or the third embodiment can also be used. Furthermore, regarding a part of the structure of each embodiment, other structures can be added / deleted / replaced.

[0072] Reference Signs

[0073] 1 - Foreign object removal device; 2 - Rotary table; 3 - Groove part; 4, 59 - Feeder; 5 - Classification part; 6 - Photographing part; 7 - Qualified product recovery part; 8 - Unqualified product recovery part; 9, 52 - Mesh housing; 10, 25, 53 - Classification mesh; 11, 54 - Space forming mesh; 12, 55 - Mesh pressing plate; 13, 58 - Pump; 14, 57 - First lifting mechanism; 16, 30, 34, 40, 43, 47, 62, 68 - Base; 18, 20, 31, 35, 39, 44, 48, 56, 65, 67 - Vibrator; 19, 64 - Second lifting mechanism; 21 - Lighting; 22 - Lens; 23 - CCD; 24 - Image processing unit; 26 - Space forming sheet; 27 - Recovery part; 28, 70 - Steering roller; 32, 36, 41, 69 - Roller; 37, 50 - Support body; 45, 49 - Low friction layer; 51 - Primary classification part; 60 - Powder conveying sheet.

Claims

1. A foreign matter removing device, characterized in that, it comprises: a substrate on which powder is disposed; and a classification unit that classifies the powder to be recovered and foreign matter particles to be removed, wherein the classification unit has: a classification screen; a vibration excitation unit that vibrates the substrate and / or the classification screen; and a pressing unit that presses the classification screen against the powder.

2. The foreign matter removing device according to claim 1, characterized in that, the mesh size of the classification screen is equal to or smaller than the size of the foreign matter particles.

3. The foreign matter removing device according to claim 1, characterized in that, a space forming unit having a plurality of spaces formed therebetween is provided between the classification screen and the pressing unit, and the cross-sectional area in the horizontal direction of each space of the space forming unit is larger than the cross-sectional area of each opening of the classification screen.

4. The foreign matter removing device according to claim 1, characterized in that, it comprises a photographing unit that photographs the residue on the substrate after classification, and based on the photographed image of the photographing unit, determines whether the residue contains the foreign matter particles.

5. The foreign matter removing device according to claim 4, characterized in that, the distance from the powder disposal surface of the substrate to the classification screen during classification is equal to or smaller than the size of the foreign matter particles.

6. The foreign matter removing device according to claim 1, characterized in that, the pressing unit is formed with a plurality of openings penetrating vertically, it comprises a suction mechanism that sucks the powder through the openings, after applying the vibration generated by the vibration excitation unit to the powder in a state where the classification screen is close to the powder, the powder is sucked by the suction mechanism in a state where the classification screen is separated from the powder.

7. The foreign matter removing device according to claim 1, characterized in that, the substrate conveys the powder in the horizontal direction, the classification screen moves along the conveying direction of the powder, and the conveyance of the substrate is synchronized with the movement of the classification screen.

8. The foreign matter removing device according to claim 7, characterized in that, the substrate is a rotating table that rotates the powder, the classification screen moves in a cycle in the tangential direction of the substrate, and the moving speed of the classification screen is greater than the speed of the powder located on the inner diameter side of the substrate and smaller than the speed of the powder located on the outer peripheral side of the substrate.

9. The foreign matter removing device according to claim 7, characterized in that, the pressing unit has a roller or a low friction layer, and the pressing unit presses the classification screen via the roller or the low friction layer.

10. The foreign matter removing device according to claim 7, characterized in that, the vibration excitation unit has a roller or a low friction layer, and the vibration excitation unit vibrates the substrate and / or the classification screen.

11. The foreign matter removing device according to claim 4, characterized in that, the substrate conveys the powder in the horizontal direction, the classification unit is located on the upstream side of the photographing unit, and another classification unit is located on the upstream side of the classification unit.

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