TWI501818B - Screening for microspheres - Google Patents

Description

Microsphere screening sieve Field of invention

The present invention relates to a microsphere screening sieve for screening microspheres of 1 mm or less and 40 μm or more.

Background of the invention

In the manufacture of microspheres (also referred to as single spheres) which require high true sphericity and narrow spherical diameter distribution, balls and shaped balls having different spherical diameters are removed. As the method of producing the metal microspheres, there are, for example, an atomization method and the like. In the atomization method, a molten metal is divided into droplets, and the droplets are spheroidized by surface tension to be solidified to form solid microspheres. In the case where the spheroidization is insufficient, it is a spindle shape ball such as an ellipsoid. In addition, in the case where two balls are welded during solidification, they become double balls (Fig. 8). Therefore, the shaped balls must be removed. Especially in the use of solder balls, bearing balls, standard size balls, spacer balls, etc., the removal of shaped balls is very important.

Regarding the screening of the shaped ball, for example, there is a device for filtering the microspheres to roll on the V groove (Patent Document 1). The screening device for a sphere according to Patent Document 1 is a surface of an inclined plate which is inclined downward from the upstream to the downstream, and a plurality of V grooves are formed in parallel from the upstream to the downstream. If the microsphere is supplied from the higher side of the V groove, the shaped ball will stop in the V groove. On the way, or down to the bottom of the board. On the other hand, since the good product is drawn to the outside of the board by drawing a parabola of a certain degree, it is a method of screening the shaped ball by using the difference of the falling point.

Further, as a method of simultaneously screening the ball diameter and removing the shaped ball, there is a method of screening by screening on a sieve plate having a mesh of a rectangle and an ellipse (Patent Document 2). In this case, if a plurality of long sides of the rectangle or the long axis of the ellipse are arranged side by side in the direction in which the plates are inclined, and the microspheres are supplied from the higher side of the plate, the shaped balls are caught by the mesh or sieved. The rolling speed of the inclined surface becomes slower and the falling point becomes closer (the flying distance becomes shorter). The spindle shape ball is screened by adjusting the length of the short side or the length of the short axis. In addition, the double ball and the snowball ball are caught by the end portions of the short side and the long axis of the joint portion, and are not dropped, so they are not recovered as good products. There are proposals to simultaneously screen the ball diameter and remove the shaped ball by setting the shape of the mesh.

The sieve unit disclosed in Patent Document 3 is such that two screens having the same pitch pitch of the holes are arranged in parallel at a constant interval, and the area where the overlap of the holes when the two sieve holes are projected onto the same plane is 90% or less. Two screens are arranged, and the interval between the two screens is 1.1 to 2.5 times the shortest length of the holes. In the proposal, since the rod-shaped shaped ball cannot pass by overlapping the holes by 90% or less, the irregular shape can be removed.

Advanced technical literature Patent literature

Patent Document 1 Japanese Patent Laid-Open Publication No. 2001-300429

Patent Document 2 Japanese Patent Laid-Open Publication No. 2006-122826

Patent Document 3 Japanese Patent Laid-Open Publication No. 2003-225586

Summary of invention

Although the above-mentioned screening device or screening screen for removing the irregular shape has the above advantages, it has the following problems. First, when the V-groove is rolled as in Patent Document 1, the shaped ball stops in the middle of the V-groove, and the subsequent good ball is also clogged and stopped, and the efficiency of the screening is lowered. In the case of screening microspheres having a diameter of 1 mm or less, it is particularly common, and even in the case of screening microspheres having a diameter of 300 μm or less, it becomes remarkable. Although the above problems can be reduced by precisely controlling the vibration of the vibrator imparted by the screen, the aforementioned control is a problem of being precise and complicated.

In the screening screen of Patent Document 2, when the spherical diameter for screening is small, it is necessary to industrially produce a high-precision mesh. Therefore, the thickness of the sieve is extremely thin, and it is difficult to maintain rigidity. In a sieve with insufficient rigidity, the ball bounces and is not suitable for rolling the ball. In addition, it is often necessary to reduce the rolling speed in order to prevent the shaped ball from skipping the mesh, and there is a tendency that the throughput is lowered. Or, there is a problem that the captured double balls are separated by the collision caused by the subsequent ball conflict, and the shaped balls are mixed into the good product. The above problem occurs in the case of screening microspheres having a diameter of 1 mm or less. In the case of screening microspheres having a diameter of 300 μm or less, it is necessary to make the thickness of the sieve to several tens of μm, and the above problems occur remarkably.

The sieve unit of Patent Document 3 is because it takes two sieves, so it takes twice or more of the time to pass one sieve. This is because, the first The two sieves are the upper space of the sieve and are restricted by the first sieve, so the probability of the microspheres falling to the sieve holes is significantly reduced. As a result, it becomes more time to screen the microspheres.

The present invention has been made in view of the above problems, and an object thereof is to provide a sieve for screening microspheres capable of efficiently removing a shaped ball, particularly a double ball.

The present inventors have reviewed a method for accurately and rapidly performing the removal of shaped balls in the shape selection of microspheres requiring a high degree of shape management. As a result, it was found that the sieve path in which the microspheres are dropped in the sieve in which the spherical diameter of the upper side of the spherical diameter distribution is removed is a geometrical shape in which only the microspheres close to the true sphere can pass, and the shaped sphere cannot pass, and the screening ability is obtained. High, correct, high speed, and arrived at the present invention. That is, the gist of the present invention is as follows.

The invention relating to claim 1 is a microsphere screening sieve which screens microspheres having a diameter 2R of 1 mm or less and 40 μm or more, and is characterized by having: a mesh opening; and a moving direction of the microspheres having passed through the mesh opening When the distance between the exit side surface of the mesh opening and the obstruction portion is S, the obstruction portion is provided at a position where R<S<4R is established; and if the diameter of the mesh hole is L When the protruding length of the obstruction portion with respect to the mesh hole is t, the obstruction portion is formed in such a manner that when the distance S is R<S<L, 0<t<L- (L ^{2 -} S ² ); in the case where the aforementioned distance S is L ≦ S < 4R, t>0 and (Lt) ² + S ² <9R ² .

The invention related to claim 2 is that the aforementioned distance S is 2R < S ≦ 3R.

According to the present invention, the shaped balls, particularly the double balls, can be removed efficiently, and the microspheres can be screened efficiently.

1‧‧‧ sieve body

2‧‧‧ mesh

3, 3A~3E‧‧‧ Obstruction Department

4‧‧‧microspheres

5, 5A~5D‧‧‧ link

6‧‧‧ sieve opening

8‧‧‧ openings

10, 10A, 10B‧‧‧ microsphere screening sieve

100‧‧‧ sieve

101‧‧‧Double balls

L‧‧‧ aperture

R‧‧‧ Radius

S‧‧‧ distance

T‧‧‧prominent length

W‧‧‧ Length of opening

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a configuration of a microsphere screening screen of the present invention.

Fig. 2 is a longitudinal cross-sectional view showing the relationship with a double sphere, (A) is an example of a conventional sieve, and (B) is an example of a sieve for screening a microsphere of the present invention.

Figure 3 is a longitudinal cross-sectional view of the microsphere screening screen of the present invention.

Fig. 4 is a view showing an example of the microsphere screening screen of the present invention (the case where the distance S is R < S < L (here, L is the diameter of the sieve opening)).

Fig. 5 is a view showing an example of the microsphere screening screen of the present invention (the case where the distance S is L ≦ S < 4R).

Fig. 6 is a view showing an example of the positional relationship between the mesh hole, the obstruction portion, and the joint portion in the projection view of the microsphere screening screen of the present invention from the upper side of the sieve side, and (A) is a view showing the present embodiment, (B) It is a figure which shows the modification 1 and (C) is a figure which shows the modification 2.

Figs. 7(A) to 7(D) are diagrams showing an example of a modification of the front end of the obstruction portion of the sieve for screening microspheres of the present invention.

Fig. 8 is a view showing the selection of microspheres, (A) is an example of a normal sphere, and (B) is an example of a double sphere.

Form for implementing the invention

Hereinafter, the sieve for screening microspheres of the present invention will be described in detail.

The microsphere screening screen 10 shown in FIG. 1 has a mesh opening 2 formed therein. The screen body 1 is provided in the obstruction portion 3 on the downstream side of the screen hole 2, and an opening 8 through which the sieved microspheres 4 pass is formed between the screen hole 2 and the obstruction portion 3. The screen main body 1 and the obstruction portion 3 are integrated by the joint portion 5. The microsphere screening screen 10 is configured such that the microspheres 4 and the shaped balls having a diameter 2R (R is a radius) of 1 mm or less and 40 μm or more can be screened by passing the balls in the order of the sieve holes 2 and the openings 8. . Incidentally, in the following description, a ball other than the shaped ball is referred to as a microball 4.

In the case of the present embodiment, the screen main body 1 is formed of a plate-like member, and a mesh hole 2 is bored in the plate thickness direction, that is, in the vertical direction in the drawing. The mesh holes 2 are formed in plural at intervals. Further, the obstruction portion 3 is disposed on the downstream side of the mesh hole 2, that is, below, and protrudes so as to cover the mesh hole 2 at the front end. The obstruction portion 3 is formed of a plate-like member that is disposed in parallel with the screen body 1. The connecting portion 5 is formed by connecting one side of the obstruction portion 3 and one side of the screen main body 1 and has a length substantially the same as one side of the obstruction portion 3. Further, the connecting portion 5 may be formed by any of the following methods, including the blocking portion 3 and the screen body 1, and may be, for example, an adhesive, followed by brazing, followed by welding, integral molding, or processing.

Regarding the mesh 2 associated with the present invention, the pore diameter L is as described above for the size of the microspheres 4 having a diameter 2R of 1 mm or less and 40 μm or more. If the diameter (target diameter) of the microsphere 4 to be screened is 2R, the aperture L of the mesh 2 is larger than the target diameter 2R of the microsphere 4. In terms of ensuring the screening accuracy, the pore diameter L of the sieve hole 2 is preferably 2R < L < 2.2R with respect to the target diameter 2R of the microsphere 4, and it is more preferable to take a 2R + spherical diameter tolerance. Therefore, the microsphere screening screen 10 of the present invention sieves a ball having a diameter larger than the target diameter of 2R, and the microspheres below the target diameter are sieved. Screening, also known as sieving, is a high-volume procedure. Usually, the microspheres having a diameter smaller than the target diameter are sieved after the aforementioned upper sieve to collect the good products of the microspheres 4 in the target diameter range. This procedure is also referred to as lower screening and the throughput is also lower than the upper sieve. The profile removal method in which the shaped ball is removed by the difference in the drop point due to the rolling is used in Patent Documents 1 and 2, and the amount of processing is low. Therefore, by the function of the above-mentioned upper screening procedure to remove the shaped ball such as the double ball 101 or the spindle shape ball, it is possible to remove the high-volume, high-speed shaped ball.

Although the plate thickness of the sieve body 1 according to the present invention is not particularly limited, if the thickness of the microsphere 4 to be screened is too thick with respect to the size of the microsphere 4 to be screened, since the sieve hole 2 becomes long, there is a slight The ball 4 takes too much time to pass through the mesh opening 2. Although the thickness of the sieve body 1 is thin, the selection of the microspheres 4 is not affected. However, if the thickness of the sieve is too thin, the strength of the sieve body 1 itself may be insufficient. Therefore, the thickness of the sieve body 1 is preferably 15 times or less, more preferably 10 times or less, of the diameter 2R of the microsphere 4. Further, although the material is concerned, the lower limit of the thickness of the sieve body 1 is preferably 30 μm or more, and more preferably 50 μm or more.

The thickness of the obstruction portion 3 according to the present invention is not particularly limited, and any thickness can obtain the effect. However, if the thickness of the sheet becomes too thin, the strength of the obstruction portion 3 is not obtained, and the ball is not obtained. The situation in which the conflict is smashed and deformed. Therefore, the thickness of the obstruction portion 3 is preferably 20 μm or more, and more preferably 40 μm or more. The thickness of the obstruction portion 3 depends on the specific gravity and the rigidity of the material. However, if the thickness of the obstruction portion 3 is too large, the obstruction portion 3 may become heavy, and the sieve to be fixed may be affected by deflection or deformation. Therefore, the thickness of the obstruction portion 3 is preferably 10 times or less the thickness of the screen body 1. When the obstruction portion 3 and the screen body 1 are made of the same material, the thickness of the obstruction portion 3 is preferably the sieve body 1 The thickness of the plate is less than 3 times.

In the microsphere screening screen 10 configured as described above, when the ball group in which the shaped ball is mixed is placed on the upper surface side of the screen body 1, the ball passes through the mesh hole 2 first. The ball that has passed through the mesh hole 2 abuts on the obstruction portion 3 to further change the moving direction. At this time, in the case where the ball is the microsphere 4, the microsphere 4 can pass through the opening 8. On the other hand, in the case where the ball is a shaped ball, the shaped ball cannot pass through the opening 8. Thus, the microsphere screening screen 10 can efficiently screen the microspheres 4 from the group of balls mixed with the shaped balls.

The conventional sieve 100 as exemplified in Fig. 2(A) can screen microspheres having different sizes, but the double spheres 101 pass through the sieve holes 2 in the direction of the sieve holes 2.

On the other hand, the microsphere screening screen 10 of the present invention has the obstruction portion 3 directly under the sieve hole 2, whereby, as exemplified in Fig. 2(B), even if the double ball 101 enters the sieve hole 2, the double The ball 101 is also unable to pass due to the obstruction portion 3. Therefore, the microsphere screening screen 10 associated with the present invention can remove the shaped ball, particularly the double ball 101, with high efficiency.

As shown in FIG. 3, by making the distance S from the exit surface of the mesh opening 2 to the obstruction portion 3 R < S < 4R, the shaped ball such as the double ball 101 or the spindle shape ball can be efficiently removed. If the distance S is equal to or less than the radius (R) of the microsphere, the microsphere 4 cannot be screened because the microsphere 4 to be screened itself cannot pass through the opening 8. Further, even if the masking portion of the mesh hole 2 caused by the obstruction portion 3 is reduced in such a manner that the microsphere 4 can pass, the double ball 101 can easily pass, and the selectivity is deteriorated. If the distance S is twice (4R) or more the diameter of the microsphere 4, the double ball 101 can easily pass through the opening 8, and the effect of the obstruction portion 3 disappears. Distance S It is preferably 2R<S≦3R. That is, the distance S is larger than the diameter (2R) of the microsphere 4 and 1.5 times (3R) or less the diameter of the microsphere 4, and the microsphere 4 can be screened more efficiently.

The microsphere screening screen 10A shown in Fig. 4 is a case where the distance S from the exit surface of the mesh opening 2 to the obstruction portion 3A is R < S < L (where L is the diameter of the mesh hole 2). In this case, the protruding length t of the front end of the obstruction portion 3A protruding from one end portion of the mesh opening 2 to the center direction of the mesh opening 2 is 0 < t ≦ L - (L ² -S ² ). As shown in Fig. 4, when S is smaller than L, the microspheres 4 are required to escape from the obstruction portion 3A, so that the length W of the opening 8 is required to be at least larger than the diameter (2R) of the microspheres. In the case of this embodiment, the length W of the opening 8 is formed to be equal to or larger than the diameter L of the mesh hole 2. That is, the protruding length t is Lt= The relationship of (W ² -S ² ) is expressed as, in the case of W=L, it becomes Lt= (L ^{2 -} S ² ), so the protruding length t from the end of the screen hole 2 to the front end of the protruding obstruction portion 3A is L- (L ^{2 -} S ² ) or less. Therefore, if the protruding length t becomes L- When (L ² -S ² ) or more, the microspheres 4 to be screened are also not passed. The smaller the difference between the diameter L of the mesh hole 2 and the diameter 2R of the microsphere 4, the more remarkable. On the other hand, when the protruding length t is t=0, since the meshing hole 2 is in a state where the obstruction portion 3A is not present immediately, the double ball 101 easily passes, and the effect of the obstruction portion 3A is not obtained.

The microsphere screening screen 10B shown in Fig. 5 is a case where the distance S from the exit surface of the mesh opening 2 to the obstruction portion 3B is L ≦ S < 4R. In this case, the protruding length t is t>0 and (Lt) ² +S ² <9R ² . That is, as shown in FIG. 5, when S is L or more, the length W of the opening 8 by the obstruction portion 3B is three times (3R) less than the diameter of the microballoon 4. Therefore, since W is represented by W ² = (Lt) ² + S ² , the relationship of (Lt) ² + S ² < 9R ² is changed from W ² < 9R ² as described above. Conversely, if the protruding length t becomes (Lt) ² + S ² ≧ 9R ² , the double ball 101 is easily passed. In addition, although the upper limit of the length t is not particularly protruded, if the obstruction portion 3B having the same length as the sieve main body 1, that is, the same size as the sieve main body 1, the microballoon 4 is formed only from the periphery of the sieve main body 1. The gap is out, so the efficiency of screening decreases. Therefore, the protruding length t should be smaller than the screen width. If the efficiency of the screening is considered, the protruding length t is preferably less than the distance between the five mesh openings 2, and more preferably the distance between the two mesh openings 2 is occluded. Further, in the case of occluding one sieve hole 2, the projection length t should preferably be 3R or less.

(Modification)

The present invention is not limited to the above-described embodiments, and can be appropriately modified within the scope of the present invention. For example, in the above embodiment, the case where the connecting portion 5 is formed to have substantially the same length as one side of the obstruction portion 3 is described. However, the present invention is not limited thereto, and may be partially fixed as shown in FIG. 6. Further, as shown in FIG. 6(C), the fixed portion may be a position that does not interfere with the action of the obstruction portion 3.

In the case where the clogging of the mesh hole by the obstruction portion 3A is made to overlap the projection portion 3A and the mesh hole on the same surface, all of the mesh holes are blocked by the obstruction portion 3 and a part of the mesh hole The case where the obstruction portion 3A is closed (for example, FIG. 4). If the front end of the obstruction portion is linear, the occluded portion of the mesh hole caused by the obstruction portion 3 is a plan view as shown in Fig. 7(A), but the linear occlusion is not satisfied as long as the condition of the present invention is satisfied. The effect of the present invention can be obtained by sieving the mesh and in what shape. The shape of the front end of the obstruction portion 3 which can be visually confirmed from the sieve hole 2 may be, for example, a shape as shown in Figs. 7(B) to (D).

Further, the shape of the front end of the obstruction portion 3 and the form of the connection portion 5 can be variously combined.

Hereinafter, the effects of the present invention will be more specifically described by way of examples.

[Examples]

(Example 1)

As shown in Fig. 3, L = 1.02 mm was prepared, and a sieve for microsphere screening for S = 1.00 mm, S = 1.02 mm, S = 1.50 mm, S = 1.53 mm, S = 1.98 mm, and S = 2.00 mm was prepared. Here, the obstruction portion 3 is formed to shield the entire surface of the opening of the mesh hole 2 as shown in FIG. Each of the sieves was provided with 1600 meshes of holes having a diameter of L at a plate thickness of 0.5 mm and a pitch of 1.5 mm. The thickness of the obstruction portion 3 is also 0.5 mm.

Deliberately, 10 double balls were mixed into about 10,000 good balls with a ball diameter tolerance of ±20 μm and a diameter of 1.00 mm (R=0.50 mm), and the above sieve was used for screening. The same screening was performed 5 times, and the average value of the number of double spheres mixed in the ball after the screening was determined.

The results are shown in Table 1. When the distance S from the exit surface of the sieve opening to the obstruction portion 3 is S=2R, the double ball does not pass through the sieve, but the good ball does not pass (screen No. 1). If S is in the range of 2R < S < 4R, the double spheres can be efficiently screened, and the good balls are completely sieved (screen Nos. 2 to 5). In particular, if it is in the range of 2R < S ≦ 3R, the double balls are all sieved out, and the good balls are all sieved (screen No. 2 to 3). If S = 4R, many of the double spheres also pass through the sieve and are not sufficiently screened (screen No. 6).

(Example 2)

The microsphere screening screen of the present invention having the dimensions of S, L, and t as shown in Table 2 was separately prepared. Each of the sieves was provided with a hole having a diameter of L of 100,000 meshes at a plate thickness of 40 μm and a pitch of 450 μm. The thickness of the obstruction portion 3A is also 40 μm.

Deliberately, 10 double balls were mixed into about 1 million good balls with a ball diameter tolerance of ±10 μm and a diameter of 300 μm, and each sieve was used for screening. The same screening was performed 5 times, and the average value of the number of double spheres mixed in the ball after the screening was determined.

The results are shown in Table 2. Here, S is a case where R<S<L. When t exceeds L- In the case of (L ² -S ² ) (No. 1, 3), the double ball did not pass, but the good ball did not pass. Under t not full L- In the case of (L ² -S ² ) (No. 2, 4), the double balls were all sieved out, and the good balls were all sieved. In the case where t is zero (No. 5), many of the double balls are also sieved and are not sufficiently screened.

(Example 3)

The microsphere screening screen of the present invention having the dimensions of S, L, and t as shown in Table 3 was separately prepared. Each of the sieves was provided with a hole having a diameter of L of 100,000 meshes at a plate thickness of 30 μm and a pitch of 80 μm. The thickness of the obstruction portion 3B is also 40 μm.

Deliberately, 10 double balls were mixed into about 1 million good balls with a ball diameter tolerance of ±5 μm and a diameter of 40 μm, and each sieve was used for screening. The same screening was performed 5 times, and the average value of the number of double spheres mixed in the ball after the screening was determined.

The results are shown in Table 3. Here, S is a case where L ≦ S < 4R. In the case of the relationship of (Lt) ² + S ² <9R ² (No. 1 to 4), the double balls are all sieved out, and the good balls are all sieved. In the case of the relationship of (Lt) ² + S ² <9R ² (No. 5), many of the double spheres were also sieved and were not sufficiently screened.

1‧‧‧ sieve body

2‧‧‧ mesh

3‧‧‧ Obstruction Department

4‧‧‧microspheres

5‧‧‧Connecting Department

8‧‧‧ openings

10‧‧‧Microsphere screening sieve

Claims (2)

A microsphere screening sieve is a microsphere screening sieve for screening microspheres having a diameter of 2R of 1 mm or less and 40 μm or more, and is characterized by having: a sieve hole; and moving direction of the microspheres having passed through the sieve hole When the distance between the exit side surface of the mesh opening and the obstruction portion is S, the obstruction portion is provided at a position where R<S<4R is established; and if the diameter of the mesh hole is L When the protruding length of the obstruction portion with respect to the mesh hole is t, the obstruction portion is formed in such a manner that when the distance S is R<S<L, 0<t<L- (L ^{2 -} S ² ); in the case where the aforementioned distance S is L ≦ S < 4R, t>0 and (Lt) ² + S ² <9R ² . The sieve for screening microspheres according to claim 1, wherein the aforementioned distance S is 2R<S≦3R.