JPH0319769A - Dresser for surface polishing machine - Google Patents

Abstract

PURPOSE:To set an uniform pass rate of pellet during the dressing of a grinding wheel in each part of the surface of the grinding wheel by setting arrangement of the pellet on a dresser in a predetermined condition. CONSTITUTION:In the case of assuming RT for radius of dresser 30, a total area of pellets, which exist within 0.5RT from the center of the dresser, occupies 13 to 20% the total area of all the pellets, further the pellet exists even within 0.4RT from the center of the dresser. Further when assumed L for distance to the pellet in a position most distant from the dresser center OT and L1 for distance to the pellet in the nearest position, the total value of length in the radial direction of bands 40, in which the pellet 32 is not present in any position in the circumferential direction in a range of the distance L1 to L2, is set to not more than the value 0.2(L2-L1). By the pellet thus arranged, the passing rate of each pellet 32 through an arbitrary point on surface a grinding wheel, is uniformly set, and irregularity in the radial direction of the grinding wheel is eliminated by evenly cutting the surface of the grinding wheel with the pellet 32.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a dresser for sharpening a grindstone of a surface polishing machine.

2. Description of the Related Art As one type of surface polishing machine for polishing objects to be polished, such as aluminum substrates for magnetic disks, the one shown in FIGS. 5 and 6 is known. That is, (A) in the figure is a flat surface polishing machine, and this polishing machine has a pair of upper and lower opposed surface plates (1
) (2), donut-shaped upper and lower grindstones (3) (4) attached to the inner surface of each surface plate, and a sun gear arranged at the axis of the grindstone between each grindstone (3) (4). (5), an internal gear (6) disposed concentrically outward of the sun gear (5), and an outer peripheral surface meshed with both the sun gear (5) and the internal gear (6). The polishing object holder (7) is provided with one or more thin plate spur gear-shaped object holders (7) arranged in the same state. Also,
Each retainer (7) is formed with a plurality of holes, into which a disc-shaped object to be polished (B) having a thicker wall than the retainer is fitted and held. Further, the upper and lower surface plates (1) and (2) are connected to the first motor (1l) via the drive Lb (la) (2a) and the sprocket L (Ib) (2b), and the motor (11) is driven. It is said that it rotates by. In addition, the upper surface plate (1)
is supported by a cylinder (not shown) so that it can be raised and lowered,
In the lowered position shown in FIG. 5, the drive shaft (1a) is engaged with the engagement portion (la') at the upper end, and a rotational force in the opposite direction to that of the lower surface plate (2) is applied. There is. On the other hand, the sun gear (5) has a drive shaft (5a) and a sprocket (5b).
to the second motor (12) via the internal gear (6)
are connected to a third motor (13) via a drive shaft (6a) and a sprocket (6b), and are rotated at different rotational speeds by the drive of these motors (3), Yuichi (12), and (13), respectively. This allows the retainer (7) to rotate and revolve like a planetary gear. In addition, the upper and lower surface plates (1) (2), the sun gear (5), and the internal gear (
The number of rotations in step 6) is set in advance to a desired ratio so that both sides of the object to be polished (B) can be processed equally.

In the illustrated surface polishing machine, the workpiece to be polished (B) is first set in the workpiece holder (7), and then the upper and lower surface plates (1) (2)
) are brought close together and the grindstones (3) and (4) are brought into pressure contact with the object to be polished (B) with a predetermined pressure. Next, each of the first to third motors (
11) Drive (12) and (13) to move the upper and lower surface plates (1
)(2), rotate the sun gear (5) and internal gear (6).

Due to the rotation of the sun gear (5) and internal gear (6), the workpiece holder (7) rotates and revolves around the rotation centers of the upper and lower grindstones (3) and (4), and the rotating grindstone (3) The polishing process of the polished object (B) is accomplished by the action of (4).

By the way, if the grinder (A) is used for a long period of time, the grindstones (3) and (4) may become clogged or damaged, so it is necessary to sharpen the grindstones (3) and (4) periodically using a dresser. be. As shown in FIGS. 7 and 8, this dresser (20) includes a dresser main body (21) shaped like a disc and a gear, which is replaceable with the object holder (7), and A plurality of cylindrical pellets of the same size (22) for dressing are buried in the end surface of the main body under the soil with their tips protruding.
It is equipped with Note that (21a) shown in FIG. 7 is a toothed portion provided on the outer peripheral surface of the dresser body (21), and (23) is a hollowed out portion for weight reduction. And the dresser (2
0) is set in place of the object holder (7) and the grinding wheels (3) and (4) are pressed against the pellet, and then the sun gear (5
) and the internal gear (6) to rotate the dresser (20) and revolve around it, while rotating the grindstones (3) and (4) to scrape off the surface of the grindstone with the tip of the pellet (22), thereby removing the surface of the grindstone. (3) It is designed to perform the sharpening described in (4).

Problem 5 to be Solved by the Invention However, when the grindstones (3) and (4) are sharpened using the conventional dresser (20) as described above, the surface of the grindstone is not flat and has large irregularities in the radial direction. It was found that this occurs. When polishing is performed using such a grindstone, the pressure distribution of the grindstone on the object to be polished becomes uneven, which causes unevenness in the amount of polishing, which in turn causes uneven surface properties of the object to be polished.

This invention was made in view of the above technical background, and it is possible to make the surface of the grindstone flat after sharpening, thereby making the amount of polishing of the object to be polished uniform, and furthermore, it is possible to make the surface of the object to be polished uniform and to improve the surface quality of the object. The purpose of this invention is to provide a dresser that enables polishing.

Means for Solving the Problems In order to achieve the above object, the inventor investigated and researched the reasons why the surface of the grinding wheel did not become a uniform flat surface after sharpening, and found that the pellet arrangement on the dresser was not appropriate.
It was found that the rate at which pellets pass through the whetstone surface during sharpening differs in each part of the whetstone surface, and the areas where the pellets pass through the wheel with a high rate are concave, and the areas where there is a low rate of pellets are convex.

Therefore, as a result of further research in order to ensure that the pellets pass through each part of the grindstone surface at a uniform rate when the I-1 is set up, it was discovered that there is an appropriate pellet arrangement on the dresser, and based on this knowledge, This completes this invention.

That is, the present invention has a plurality of sharpening pellets (32) provided on the end surface of a disc-shaped dresser main body (31) with the tip protruding, and a rotating grindstone ( 3) A dresser (30) for a surface polishing machine, which sharpens the grindstone by rotating and revolving around the rotation center of (4) with the pellet (32) in pressure contact with the grindstone surface. In the dresser (3
If the radius of 0) is RT, then 0.5 from the center of Doreza
The total area of pellets existing within RT occupies 13 to 20% of the total area of all pellets, and pellets also exist within 0.4 RT from the dresser center (○T), and 7 from the dresser center (OT). When the distance to the farthest pellet is L2 and the distance to the nearest pellet 1 is L1, there are pellets (32 ) does not exist, the total value of the radial length of the band v (40) is 0.
2 (L2 - L1) or less.

Effect: By arranging the pellets as described above, the grinding wheels (3) (4)
The rate at which each pellet (32) passes through any point on the surface is made uniform, and as a result of the grinding wheel surface being evenly ground by the pellets, unevenness in the radial direction of the grinding wheel is eliminated.

Embodiment In FIG. 1, (30) is a dresser, and the dresser consists of a dresser body (31) and a plurality of dressing pellets (32). The dresser main body (31) has a disc shape with a predetermined thickness, and a polishing machine (see FIG. 5) is installed on its outer peripheral surface.
A toothed portion (31a) is formed to mesh with both the sun gear (5) and the internal gear (6) of A). This dresser main body (31) is made of SUS, but its weight is reduced by providing a pair of hollowed-out portions (33) that are partially hollowed out in the thickness direction in a fan-shape.

On the other hand, the pellets (32) are all made of the same large cylindrical diamond sintered body, and as shown in FIG.
) with its tip protruding, and is joined to the dresser body (31) by silver brazing. (34) shown in FIG. 2 is a brazed part. In addition, pellets (3
2) does not necessarily have to be the same size. In addition, pellets (
Fine irregularities (32a) are formed on the protruding end surface of the grinding wheels (32) to allow the grinding wheels (3) and (4) to stand on their own.

In this invention, the arrangement of the pellets (32) must be set as follows. That is, as shown in Fig. 1, if the radius of the dresser (30) is RT, then the total area of pellets l- (32) existing within 90.5 RT from the center of the dresser (OT) is the total area of the pellets l.・It must be 13-20% of the area. Particularly preferably 14.0 to 17.5% of the total area
It is better to set it to . Second, the center of the dresser (O
It is necessary that the pellet (32) also exists within 0.4R-r from T). Particularly preferably Doreza center (
It is preferable that the pellets also exist at a position within 0.3 RT, more preferably within 0.2 RT. Thirdly, if the distance from the center of the dresser (OT) to the pellet at the farthest position is L2, and the distance to the pellet at the closest position is L1, as shown in Figure 3, L
The length in the radial direction of the zone (40) (indicated by diagonal lines in Fig. 3) in which there is no pellet l·(32) at any position in the circumferential direction in the range from 1 to L2 is expressed as A1, n2... If n1-tl22+...≦0. 2 (L2
-L1). This means that L1-L2
If you draw a circle with a radius of 1,000 points from the Doreza center (○T) in the range, this means that the probability that this circle will not hit any pellet is 0.2 or less. Particularly preferably, when a circle with a radius of 0, that is, an arbitrary radius, is drawn, the field should be set so that it always hits one or more pellets (32).

By arranging the pellets to satisfy the above conditions, each pellet (
32) will pass through uniformly. On the other hand, if any of the pellet arrangement conditions are deviated from, the surface of the grinding wheel will have parts where each pellet passes through more and less parts during sharpening, resulting in an uneven dressing amount and unevenness in the radial direction of the grinding wheel. become something that

To sharpen the grindstones (3) and (4) using the dresser (30) shown in Figs. gear(
5) and the internal gear (6), and then the grindstones (3) and (4) are brought into pressure contact with the pellets (32) of the dresser (30). In this state, the sun gear (
5) and the internal gear (6).
1 Rotate and revolve the base plate (30), and at the same time
)(2) That is, rotate the grindstones (3) and (4). Then, based on the relative motion between the grinding wheels (3) (4) and the dresser (30), pellets (
32), the surface of the grindstone is scraped off, thereby performing sharpening.

By the way, the rate at which the pellet (32) passes through any given surface of the grinding wheels (3) and (4) is calculated as the distance at which the pellet passes for each point on the grinding wheel surface (hereinafter referred to as "passing distance" in i11). In other words, as shown in Fig. 4, if it is assumed that one circular pellet of radius Rp exists at a distance of radius R from the center of the dresser (OT), then the radius from the center of the grinding wheel (Ov) Point Z at position r
Circumferential average value f of passing distance at (r, θ)
(r) is given by the following formula.

[Left below] 12 i) When C-R+Rp<r<C0R-Rp, f (r)
- (t/π)! ”,: v (r, θ)・β(r
, Re ) dθ and v (r, θ)−(π/30) CN
T +r (Nv -NT) +2Cr
Nr (Nw-NT)COSθβ(r, Re)
= (1/ π) co s−' { CRa 2+
R2R p2) / 2Ra ・Distance t ('sec) to Rl center (○T): Dressing time v (r, θ): Relative speed between grinding wheel and dresser (pellet) β (r, Re): Above dresser Ratio of pellets 1 on the circumference of radius R, U) C-R-Rp≦'≦C-R+Rp or C+R-R
When p≦r≦C+R+Rp, f (r) = (t/ff) J':2v (r, θ
)・β(r, Re) dθiii) r<C−R−
When Rp or C+R+Rp<r, f b) -0 However, in the above equation, NT (rpm) ・Rotation speed of the dresser Nν (rp
m): Rotational speed of the grinding wheel R (mm): Distance Rp from the dresser center (OT) to the pellet center (Op) Cmm): Pellet radius C (mm): From the grinding wheel center (Oν) to the dresser 13 The above equations are As mentioned above, this shows the passing distance when one circular pellet (32) with radius Rp exists at a distance of radius R from the center of Dore-Sosa (OT), but the distance R from the center of dresser (OT) When there are χ pellets, the passing distance at each point of the grindstones (3) and (4) can be calculated by multiplying the passing distance f (r) in the case of one pellet by χ. Also, individual pellets (3
The passing distance F (r) of each point of the grinding wheel according to 2) is the sum of the passing distances of each pellet, that is, F (r) = f1 (r) + f2 (r) + f3 (
It can be calculated as r) 10...+fn (r) 14 (where n is the number of pellets). If the passing distance F(r) of each point of the grindstone is equal, the amount of grinding by the pellet (32) will be equal, and the surface of the grindstone will be flat.

Incidentally, the Doreza (30) according to the present invention shown in FIG.
and the conventional Trezza (20) shown in FIG. 8, the lower grinding wheel (
4) Calculate the passing distance of each point in the radial direction, and
The surface roughness in the radial direction of the lower grindstone (4) was actually measured when sharpening was actually performed.

[Left below] 15 (Conditions) Inner radius of whetstone + 18!5mm Outer radius of whetstone:! 565mm Dresser radius RT: 211.67mm Distance between centers of grinding wheel and dresser C: 374.7mm Pellet radius Rp: 8mm Dresser rotation speed N T: OJ78 X50rpm
Relative rotation speed of lower surface plate (grindstone): 0.839 X50
rpm Lower surface plate (grinding wheel) rotational speed Nw: 50 rpm Dressing time t: 20 seconds The calculation results of the passing distance are shown in FIG. 9 for the product implementing the present invention and in FIG. 10 for the conventional product.

Further, the actual results of the surface roughness of the grindstone are shown in FIG. 11 for the product implementing the present invention and in FIG. 12 for the conventional product.

From the above results, in the conventional product, since there are no pellets near the inside of the dresser (20), the passing distance peaks near the inner and outer peripheries of the grinding wheel (4), and the corresponding positions also occur in the 17 In contrast, in the case of the product according to the present invention, the passing distance of the pellet or each point on the grindstone is similar, and actual measurements also show that the surface of the grindstone is flat.

Effects of the Invention As described above, the present invention has a plurality of sharpening pellets provided at the end of a disc-shaped tresor body with a protruding tip, and the pellets are rotated around the center of rotation of a rotating grindstone. In a dresser for a surface polishing machine, which sharpens the whetstone by rotating and revolving around the whetstone while pressing it against the whetstone surface, by setting the pellet arrangement on the dresser to a predetermined condition, the The rate at which pellets pass through can be made uniform at each part of the grindstone surface. The mulch and the surface of the grindstone can be scraped off uniformly by pellets, and the surface of the grindstone can be sharpened into a flat surface with few irregularities.

Therefore, when polishing is performed using such a sharpened whetstone, the pressure distribution of the whetstone to the object to be polished can be made uniform,
As a result, it becomes possible to provide polished objects with excellent surface properties and quality.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a dresser according to an embodiment of the present invention;
Figure 2 is a cross-sectional view of Figure 1 along the line 1 and Figure 3 is a
Fig. 4 is a schematic plan view of the dresser to explain one of the arrangement conditions, Fig. 4 is a schematic plan view showing the relationship between the dresser and the grinding wheel when calculating the pellet passing distance on the grinding wheel surface, and Fig. 5 is a plan view. FIG. 6 is a front partial cross-sectional view showing an example of a polishing machine, FIG. 6 is a perspective view of essential parts showing the usage state of the flat surface polishing machine shown in FIG. 5, and FIG. FIG. 8 is a plan view of a conventional dresser.
FIG. 9 is a graph showing the calculation result of the passing distance of the grindstone surface when using the dresser according to the present invention, FIG. 10 is a graph showing the calculation result of the passing distance of the grindstone surface when using the conventional dresser, Fig. 11 is a graph showing the actual measurement results of the surface roughness of the grindstone when dressing was performed using the dresser according to the present invention, and Fig. 12 is a graph showing the surface roughness of the grindstone when dressing was performed using the conventional dresser. It is a graph showing actual measurement results of roughness. (30)...Drezza, (31)...Drezza body,
(32)...Pellet, (40)...Band, (3)(
4)...Whetstone, (A)...Surface polishing machine. Above 20 Unexamined Japanese Patent Publication No. 3-19769 (7) (mm) (mm) Distance between the IC in the stone (mm) Figure 9 h I distance from the IC in the Tomoe stone (mm) Figure 10

Claims (1)

[Scope of Claims] A disc-shaped dresser main body (31) has a plurality of dressing pellets (32) provided on the end surface thereof with the tips protruding,
A surface polishing machine for use in a surface polishing machine, which sharpens the whetstones by rotating and revolving around the center of rotation of the rotating whetstones (3) and (4) with the pellets (32) in pressure contact with the whetstone surfaces. In the dresser (30), if the radius of the dresser (30) is R_T, the total area of pellets existing within 0.5R_T from the center of the dresser occupies 13 to 20% of the total area of all pellets, and the center of the dresser ( When there are pellets within 0.4R_T from O_T), and the distance from the center of the dresser (O_T) to the pellet at the farthest position is L_2, and the distance to the pellet at the closest position is L_1, The total value of the radial length of the zone (40) in which no pellet (32) exists at any position in the circumferential direction in the range of L_1 to L_2 is 0.
．． 2 (L_2-L_1) or less.