JPH089142B2 - Dresser for surface polishing machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dresser for dressing a grindstone of a flat surface grinder.

2. Description of the Related Art For example, one of flat polishing machines for polishing an object to be polished such as an aluminum substrate for a magnetic disk is shown in FIGS.
The one shown in the figure is known. That is, in the figure (A)
Is a surface grinder, and the grinder comprises a pair of upper and lower facing plates (1) and (2), donut-shaped upper and lower whetstones (3) and (4) attached to the inner surface of each platen, and whetstones. (3) A sun gear (5) arranged at the axis of the grindstone between (4) and an internal gear (6) arranged concentrically outside the sun gear (5)
And one or more thin plate spur gear-shaped workpiece holders (7) arranged such that their outer peripheral surfaces are meshed with both the sun gear (5) and the internal gear (6). I have it.
In addition, a plurality of holes are formed in each technician (7),
The disk-shaped object to be polished (B), which is thicker than the cage, is held in this hole in a fitted state. further,
The upper and lower surface plates (1) and (2) are connected to the first motor (11) via the drive shafts (1a) and (2a) and the sprockets (1b) and (2b), and are rotated by the drive of the motor (11). Has been made. The upper surface plate (1) is movably supported by a cylinder (not shown) and engages with an engaging portion (1a ') at an upper end of the drive shaft (1a) in a lowered position shown in FIG. , And a rotational force in the opposite direction to the lower surface plate (2) is applied. On the other hand, the sun gear (5) has a drive shaft (5
a) and the sprocket (5b) through the second motor (1
2), and the internal gear (6) is connected to the third motor (13) via the drive shaft (6a) and the sprocket (6b), respectively, and by driving these motors (12) and (13), respectively. It is designed to rotate at different rotational speeds, whereby the cage (7) can be revolved around the planetary gear while rotating on its axis. The rotation speeds of the upper and lower surface plates (1) and (2), the sun gear (5), and the internal gear (6) are set to predetermined ratios so that both surfaces of the work (B) can be processed equally. Has been done.

In the illustrated flat polishing machine, the object to be polished (B) is first set on the object to be polished holder (7), and then the upper and lower surface plate (1).
The grinding stones (3) and (4) are brought into close contact with the object (B) to be polished with a predetermined pressure. Next, drive the first to third motors (11) (12) (13) to move the upper and lower surface plate (1).
(2) Rotate the sun gear (5) and the internal gear (6). By the rotation of the sun gear (5) and the internal gear (6), the object-to-be-polished holder (7) revolves around the rotation centers of the upper and lower grindstones (3) and (4) while revolving and rotating. (4)
By this action, the object to be polished (B) is polished.

By the way, if the grinder (A) is used for a long period of time, the grindstones (3) and (4) will be clogged or crushed. Therefore, it is necessary to periodically grind the grindstones (3) and (4) with a dresser. Such a dresser (20) is shown in FIGS.
As shown in the figure, the dresser main body (21) formed in a disk shape and a gear shape that can be replaced with the object holder (7).
And a plurality of columnar pellets (22) of the same size, which are embedded in the upper and lower end surfaces of the main body in a protruding state of the tip. Note that (21a) shown in FIG. 7 is a tooth portion provided on the outer peripheral surface of the dresser body (21), and (23) is a lightening portion for reducing the weight. Then, the dresser (20) is set in place of the object holder (7), the grindstones (3) and (4) are pressed against the pellets, and then the sun gear (5) and the internal gear (6).
By rotating the dresser (20) while revolving it while rotating the grindstones (3) and (4), the surface of the grindstone is scraped off by the tip of the pellet (22), and thus the grindstone (3)
It is said that the setting of (4) is performed.

However, when the dressing wheels (3) and (4) are sharpened by the conventional dresser (20) as described above, the surface of the grinding wheel is not flat and large irregularities are generated in the radial direction. It has been found. When polishing is performed using such a grindstone, the pressure distribution of the grindstone on the object to be polished becomes non-uniform, which causes unevenness in the amount of polishing, which in turn causes unevenness in the surface properties of the object to be polished.

The present invention has been made in view of such technical background, the surface of the grindstone after dressing can be made flat and the polishing amount of the object to be polished can be made uniform, and thus the object to be polished having excellent surface properties can be obtained. The purpose is to provide a dresser that enables polishing.

Means for Solving the Problems In order to achieve the above object, the inventor conducted an investigation and research on the reason why the grindstone surface after dressing does not become a uniform flat surface, and because the pellet arrangement on the dresser is not appropriate, the grindstone at the time of dressing It was found that the rate at which the pellets pass through the surface was different in each part of the surface of the grindstone, and the part with a high pass rate was concave and the part with a low pass rate was convex.

Therefore, as a result of further research to make the pellets pass through each part of the grindstone surface at a uniform rate during dressing, it was found that there is an appropriate pellet arrangement on the dresser, and the present invention is based on such findings. It has been completed.

That is, according to the present invention, as shown with reference to the reference numerals in the drawings, a rotating grindstone having a plurality of setting pellets (32) provided in a protruding state on the end surface of a disk-shaped dresser body (31) is provided. 3) A dresser (30) for a flat grinding machine, which is designed to revolve around the center of rotation of (4) while revolving while rotating the pellet (32) against the surface of the grindstone under pressure. in dresser if the radius (30) and the R _T, the total area of the pellets present within 0.5 R _T from the dresser center accounted for 13-20% of the total area of all the pellets, and the dresser center (O _T) If there is a pellet within 0.4 R _T from the center and the distance from the dresser center (O _T ) to the farthest pellet is L ₂ , and the distance to the closest pellet is L ₁ , , the circumferential direction in the range of L ₁ ~L ₂ Which position also absent pellets (32) band (40)
It is characterized in that the total value of the radial length of is less than 0.2 (L ₂ −L ₁ ).

Action With the above pellet arrangement, the grindstone (3)
(4) The rate at which each pellet (32) passes through an arbitrary point on the surface is made uniform, and the surface of the grindstone is ground evenly by the pellets. As a result, unevenness in the radial direction of the grindstone is eliminated.

Embodiment In FIG. 1, (30) is a dresser, which comprises a dresser body (31) and a plurality of dressing pellets (32). The dresser body (31) has a disk shape with a predetermined thickness, and the outer peripheral surface thereof has a polishing machine (A) shown in FIG.
The tooth portion (31a) meshing with both the sun gear (5) and the internal gear (6) is formed. The dresser main body (31) is made of SUS, and its weight is reduced by providing a pair of thinned portions (33) in which the thickness direction is partially hollowed out.

On the other hand, each of the pellets (32) is made of a diamond sintered body having the same large columnar shape, and the tip of the pellet (32) protrudes into a fitting recess (31b) provided on the end face of the dresser body (31) as shown in FIG. And is joined to the dresser body (31) by silver brazing. (34) shown in FIG. 2 is a brazing part. The pellets (32) do not necessarily have to be the same size. Further, fine protrusions (32a) for dressing the grindstones (3) and (4) are formed on the protruding end surface of the pellet (32).

The arrangement of the pellets (32) should be set as follows in the present invention. That is, first, as shown in FIG. 1, if the radius of the dresser (30) as the R _T, the area total area of all the pellets of the pellet (32) present within 0.5 R _T from the dresser center (O _T) Must be 13 to 20%. Particularly preferably, it is set to 14.0 to 17.5% of the total area. Secondly, 0.4R from the dresser center (O _T ).
It is necessary that the pellet (32) is also present within _T. Particularly preferably, the pellets are present at a position within 0.3R _T, more preferably within 0.2R _T from the dresser center (O _T ). Thirdly, when the distance to the pellet farthest from the dresser center (O _T ) is L ₂ and the distance to the closest pellet is L ₁ , as shown in FIG. In the range of L _{1 to} L ₂ , the radial length of the zone (40) (shown by diagonal lines in FIG. 3) where the pellet (32) does not exist at any position in the circumferential direction is l ₁ , l ₂ ... If
l ₁ + l ₂ + ... ≦ 0.2 (L ₂ −L ₁ ) must be satisfied. This means that when depicting any radius of the circle from the dresser center (O _T) in the range of L ₁ ~L _2, meaning that the probability of this circle is not hit in any of the pellets is 0.2 or less.
Particularly preferably, when drawing a circle of 0, that is, an arbitrary radius,
It is better to set this circle so that it always hits one or more pellets (32).

By making a pellet arrangement that satisfies the above conditions,
Each pellet (32) uniformly passes through each part of the surface of the grindstones (3) and (4) during dressing. On the other hand, if any of the pellet placement conditions is exceeded, a portion where each pellet passes through at the time of sharpening and a portion where the proportion of each pellet passes through are small on the surface of the grindstone, and the sharpening amount becomes uneven, resulting in unevenness in the radial direction of the grindstone. Becomes

In order to dress the whetstones (3) and (4) using the dresser (30) shown in FIGS. 1 and 2, the dresser (30) has its outer peripheral tooth portion (31a) of the sun of the grinder (A). It is arranged so that it meshes with both the gear (5) and the internal gear (6),
Then, the grindstones (3) and (4) are pressed against the pellets (32) of the dresser (30). In this state, by rotating the sun gear (5) and the internal gear (6), the dresser (30) is rotated and revolved, and at the same time, the surface plate (1) (2), that is, the grindstones (3) (4) is rotated. Let Then the whetstone (3)
Based on the relative movement between (4) and the dresser (30), the grindstone surface is scraped off by the pellets (32) which successively pass over the surfaces of the grindstones (3) and (4), so that the sharpening is performed.

By the way, the ratio of the pellets (32) passing through any surface of the grindstones (3) and (4) is calculated by calculating the distance that the pellets pass with respect to each point on the surface of the grindstone (hereinafter simply referred to as “passing distance”). be able to. That is, as shown in FIG. 4, a radius R is measured from the dresser center (O _T ).
Assuming one circular pellet of R _P is present,
Point Z (r, theta) positions of a radius r from the grindstone center (O _W) circumferentially average f of passing distance in (r) is given by the following equation.

i) When C−R + R _p <r <C + R−R _p However, ii) C−R−R _p ≦ r ≦ C−R + R _p or C + R−R _p ≦ r
When ≦ C + R + R _p iii) When r <C−R−R _p or C + R + R _p <r f (r) = 0 However, in the above formula, N _T (rpm): dresser rotation speed N _W (rpm): grinding wheel rotation speed R ( mm): Dresser center (O _T ) to pellet center (O _p ).
The distance to the R _p (mm): pellet radius C (mm): grinding wheel center (O _W) from the dresser center (O _T) distance to t (sec): Dressing time v (r, θ): grinding wheel and dresser ( Relative velocity with the pellet) β (r, R _θ ): Of the circumference of radius R _θ on the dresser,
Percentage of Pellets Present The above equations show the passage distance when there is one circular pellet (32) of radius R _{P at} the distance of radius R from the dresser center (O _T ) as described above. , when x number of pellets are present in a distance from the dresser center (O _T) of R, the grinding wheel (3) passing distance f (r) when passing distance of one pellet at each point (4) Multiply by x. Further, the passage distance F (r) of each point of the grindstone by the individual pellets (32) on the dresser (30) is the sum of the passage distances by the respective pellets, that is, F (r) = f ₁ (r) + f ₂ (r) + f _It can be calculated by ₃ (r) + ... + fn (r) (where n is the number of pellets). Then, if the passing distances F (r) of the respective points of the grindstone are equal, the amount of scraping by the pellets (32) becomes equal, and the surface of the grindstone becomes flat.

Incidentally, the dresser (30) according to the present invention shown in FIG.
And the conventional dresser (20) shown in FIG. 8 are used to calculate the passing distance of each point in the radial direction of the lower grindstone (4) in the grinder shown in FIG. 5 under the following conditions. The surface roughness in the radial direction of the lower grindstone (4) was actually measured when the grinding was actually performed.

(Conditions) Inner wheel radius: 185mm Outer wheel radius: 565mm Dresser radius R _T : 211.67mm Center distance between wheel and dresser C: 374.7mm Pellet radius R _P : 8mm Dresser rotation speed N _T : 0.378 × 50rpm Lower surface plate ( Relative rotation speed of grinding wheel: 0.839 × 50 rpm Rotation speed of lower surface plate (grinding wheel) N _W : 50 rpm Dressing time t: 20 seconds
Fig. 10 shows the conventional product in Fig. 10. Further, the measurement results of the surface roughness of the grindstone are shown in FIG. 11 for the product of the present invention and in FIG. 12 for the conventional product.

From the above results, in the conventional product, there is no pellet near the inside of the dresser (20), so a peak of the passing distance occurs near the inner and outer peripheries of the grindstone (4), and unevenness is severe at the position corresponding to this even in actual measurement. On the other hand, in the product of the present invention, the passage distance of the pellet is similar at each point of the grindstone, and it can be seen from the actual measurement that the grindstone surface is flattened.

EFFECTS OF THE INVENTION The present invention, according to the above, has a plurality of dressing pellets provided in a tip protruding state on the end surface of the disk-shaped dresser body, and around the rotation center of the rotating grindstone, the pellets are In a dresser for a flat grinding machine, which is intended to sharpen the grindstone by revolving while revolving in a state of being pressed against the surface of the grindstone, by setting the pellet arrangement on the dresser to a predetermined condition, pellets are set when the grindstone is sharpened. It is possible to equalize the rate at which the particles pass through each part of the grindstone surface. As a result, the grindstone surface can be evenly scraped off by the pellets, and the grindstone surface can be sharpened to a flat surface with few irregularities. Therefore, when polishing is performed using such a sharpened grindstone, the pressure distribution of the grindstone to the object to be polished can be made uniform, and thus it is possible to provide the object to be polished having excellent surface properties and quality.

[Brief description of drawings]

FIG. 1 is a plan view of a dresser according to an embodiment of the present invention,
Fig. 2 is a sectional view taken along the line II-II in Fig. 1, Fig. 3 is a schematic plan view of a dresser for explaining one of the arrangement conditions of pellets, and Fig. 4 is a calculation of the pellet passage distance on the surface of the grindstone. FIG. 5 is a schematic partial plan view showing the relationship between the dresser and the grindstone when the polishing is performed, FIG.
FIG. 7 is a perspective view of a main part showing a usage state of the flat grinding machine shown in FIG. 7, FIG. 7 is a perspective view of a main part for explaining a method of setting a grindstone in the grinding machine of FIG. 5, and FIG. 8 is a plan view of a conventional dresser. FIG. 9 is a graph showing the calculation result of the passage distance of the grindstone surface when the dresser according to the present invention is used, and FIG. 10 is a graph showing the calculation result of the passage distance of the grindstone surface when the conventional dresser is used. , FIG. 11 is a graph showing the measurement results of the surface roughness of the grindstone when dressing is performed using the dresser according to the present invention, and FIG. 12 is the surface of the grindstone when dressing is performed using the conventional dresser. It is a graph which shows the measurement result of roughness. (30) ... Dresser, (31) ... Dresser body, (32) ... Pellet, (40) ... Band, (3) (4) ... Grindstone, (A) ...
Flat surface polishing machine.

Claims (1)

[Claims] 1. A plurality of dressing pellets (32) provided on the end surface of a disk-shaped dresser main body (31) in a protruding state.
A flat surface having a sharpening wheel by rotating around the center of rotation of the rotating grindstones (3) and (4) while revolving around the rotation axis of the pellet (32) in pressure contact with the grindstone surface. in dresser (30) for grinding machines, if the radius of the dresser (30) as the R _T, the total area of the pellets present within 0.5 R _T from the dresser center accounted for 13-20% of the total area of all the pellets , And there is a pellet within 0.4R _T from the dresser center (O _T ), and the distance to the pellet farthest from the dresser center (O _T ) is L ₂ , and the distance to the closest pellet is When the distance is L ₁ , the total radial length of the zone (40) where the pellet (32) does not exist at any position in the circumferential direction in the range of L _{1 to} L ₂ is 0.2 (L ₂ de for surface grinding machine, characterized in that -L ₁₎ or less Tsu support.