JPS62166958A - Surface plate for polishing concave face - Google Patents

Abstract

PURPOSE:To perform efficient and highly accurate polish machining by providing plural concentric grooves having the same center point as the rotating center of a surface plate so that the groove interval is decreased as the groove is separated from the center. CONSTITUTION:A laser rod (sample) 7 is fitted to a sample fitting jig 6 integrally made with a correction ring 5 and polished with a surface plate 1. Plural grooves 8 provided on the polishing face of this surface plate 1 are concentric circles around the center point of the rotary shaft 9 of the surface plate 1 and are notched so that the groove interval is decreased proportionally as the groove is separated from the center point. As a result, normal forces F applied to the polishing face of the surface plate 1 by plural samples 7 are made equal, thus the curvature of the surface plate 1 is not changed after polishing for a long time, and efficient and highly accurate polish machining can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to parts for optical instruments having lenses or lens-like parts, and particularly to a polishing surface plate used for polishing the concave surface of the parts.

(Prior art) Conventionally, in order to polish the concave surface of a concave lens, etc., as shown in Figure 1, a plurality of coarsely polished samples (lenses) are attached or fixed to a polishing plate 3, and the sample surface is polished. It is brought into contact with the polishing surface of the surface plate 1, which is a machine. In this installed state, the surface plate is rotated around its central axis at a predetermined speed, and the polishing plate 3 is reciprocated in the radial direction of the rotating surface plate using the hairpin 4 provided on the top surface of the polishing plate, so that the sample surface can be polished. Perform polishing. In this case, it is known that if grooves of various shapes are formed on the polishing surface of the surface plate, the polishing efficiency of the sample will be increased, although the surface plate will wear out more quickly.

By the way, this polishing method using hairpin oscillation can provide stable polishing accuracy when the diameter-to-thickness ratio is small, such as an ordinary lens. Example 3 φ There is a drawback in that if too much is exceeded, the oscillating motion becomes unstable, making it impossible to obtain good accuracy. In order to solve all of the above-mentioned problems, there is a known corrective wheel polishing process. This method does not require the above-mentioned swinging by the hairpin, and even with a long sample such as a laser rod, the precision of the product will not be significantly impaired.

(Problems to be Solved by the Invention) In the modified wheel polishing method described above, compared to the conventional method, although the instability factor for polishing accuracy, such as hairpin swing, is reduced, the following problems are newly introduced. occured. That is, in the modified wheel polishing method, as shown in Fig. 2, the axis (normal line) of the jig 6 for fixing the sample to the polishing surface of the surface plate 1 has an inclination angle 2 with respect to the rotation axis of the surface plate. As a result, the normal line between the sample (laser rod) 7 and the polishing surface of the surface plate also has an inclination angle with respect to the rotation axis. If the axis of rotation is assumed to be vertical, then the force F in the normal direction applied to the polished surface of the surface plate of multiple samples is ω, respectively θ (ω is the force in the vertical direction (gravity), θ is the normal and the rotation ), and depending on the distance from the center of the surface plate, the angle between the sample and the surface of the surface plate becomes larger at points closer to the center, so the frictional force between the sample and the surface plate is The closer it is to the center, the larger it is.

As a result, the degree of wear on the polished surface near the center of the surface plate is greater than that on the outer periphery, which causes the problem that the curvature of the concave surface to be polished also increases, leading to deterioration in the processing accuracy of the product.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems. A plurality of concentric grooves having the same center point are provided such that the groove interval becomes smaller in proportion to the distance from the center.

(Embodiment) FIG. 2 is a side view including a partial cross section showing an embodiment of the present invention. 5 is a correction ring, 6 is a sample mounting jig integrated with the correction ring,
7 was a laser rod (sample), and 8 was provided on the polished surface of the surface plate 1. A plurality of grooves are shown concentrically with respect to the center point of the rotating shaft 9 of the surface plate 1, and the grooves are carved so that the distance between the grooves decreases in proportion to the distance from the center point. In this example, the diameter of the tin surface plate was 300 ran, and the total radius was 200.
0mm, and the width of the plurality of grooves is 0.7rWn, and the width increases by 20Wn from the center point side toward the outer periphery.
It took 5 hours to polish the surface with grooves carved at intervals of 0.01 m + n starting from mm intervals, and with grooves of 0.7 mm width uniformly carved at intervals of 2 mm as before. After doing.

When we looked at the changes in curvature, we found that although no change in curvature was observed in the former case, a 1% change in curvature was measured in the latter case.

(Effects) As explained above, when the polishing surface plate according to the present invention is used, firstly, since it is a modified wheel polishing method, the amplitude that relies on the experience and intuition of the operator, which is required in the oscillating polishing method, can be reduced. Not only does it not require any adjustment or centering, but the curvature of the surface plate does not change even after long polishing operations, allowing efficient and highly accurate concave polishing. This can be expected to have the effect of making it easier for people to get sick.

Remaining days below

[Brief explanation of drawings]

FIG. 1 is a side view showing a conventional example of a concave polishing method using a rotating polishing plate. FIG. 2 is a side view, including a partially broken surface, when the surface plate of the present invention is applied to a modified wheel polishing method. In the figure, 1... Surface plate, 5... Correction wheel, 6... Sample mounting jig integrated with correction wheel, 7... Laser 07 do (sample)
. 8...Concentric grooves.

Claims (1)

[Claims] In a concave polishing surface plate used for concave polishing by a modified wheel polishing method and having a plurality of grooves concentric with the center of rotation on the rotating polishing surface, the intervals between the plurality of concentric grooves are adjusted. . A surface plate for concave polishing, characterized in that the surface plate is small in proportion to the distance from the center of rotation.