JPH1086053A - Polishing method and polishing apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A polishing method capable of obtaining a finished surface with extremely high shape accuracy without special skill.
Also, a polishing apparatus used for the same is provided. SOLUTION: The polishing apparatus 1 of the present invention has a sheet polisher 21 and a polisher feed mechanism (a driving roller 35 or the like) for reciprocating the sheet polisher. Further, a means (such as the air cylinder 5) for applying the work 11 to the processing surface of the sheet polisher 21 is provided. Further, a means (magnetic fluid layer 23, electromagnet 25) for changing the pressing of each part of the sheet polisher 21 against the processing surface is provided for each part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method suitable for surface finishing of a rod-shaped optical element (lens, mirror) and the like, and a polishing apparatus used for the polishing method. In particular, a polishing method capable of obtaining a finished surface with extremely high shape accuracy without requiring special skills, and
The present invention relates to a polishing apparatus used for the same.

[0002]

2. Description of the Related Art In the surface finishing of optical elements such as lenses, prisms and mirrors, an elastic polishing tool generally called a pad polisher or a pitch polisher has been conventionally used. The pad polisher is obtained by attaching abrasive grains to the surface of a polyurethane pad. The pitch polisher is a mixture of abrasive grains and oils and fats. The relative movement of the tool and the work (workpiece) is slid, and abrasive grains interposed at the interface between the tool and the work are responsible for the main material removal. As a polishing apparatus used for such processing, a horizontal swing type polishing machine usually called an Oscar type or a circular swing type polishing machine has been used.

FIG. 4 is a diagram showing a main part of a conventional typical polishing apparatus having a pad polisher. (A)
Is a side view, and (B) is a plan view. 4 has a disk-shaped rotating lapping machine 111. A polyurethane pad 109 is attached to the upper surface of the lapping machine 111. A polishing liquid containing abrasive grains is supplied from the nozzle 104 to the upper surface of the polyurethane pad 109.

A work 107 is placed on a polyurethane pad 109 while being held in a work holder 105. The work holder 105 has a disk shape as a whole, but a concave portion 106 in the shape of a work 107 is dug down on the lower surface, and the work 107 is fitted into the concave portion 106. Then, the lower surface of the work 107 is pressed against the surface of the polyurethane pad 109 for processing. The work holder 105 is pressed from above by a work holder support bar 103 (commonly referred to as a kansashi pin), and is reciprocated right and left (traverse). The kansashi pin 103 and the work holder 105
Is a spherical bearing. Therefore, the work holder 105 and the work 107 traverse and rotate (rotate) by receiving the total moment of the rotational friction force from the polyurethane pad 109 applied to the work 107. And this work 10
7 own rotation / traverse and polyurethane pad 10
9 (lapping machine 111) relatively slide at a sliding speed corresponding to the rotation speed difference.

[0005]

The above-mentioned processing using a conventional lapping machine has the following problems. In conjunction with the rotation of the work described above, particularly when the work is an elongated rod-shaped object, a frictional force is applied in the opposite direction to the work surface from the center of the work as a starting point. It tends to have a twisted surface shape as shown.

FIG. 5 is a diagram schematically showing a processing habit of a rod-shaped work in the conventional lapping machine polishing.
(A), (C) is a side view, (B) is a front view. In the drawing, a portion (enlarged) where a broken line portion 203 on the lower surface of the work 201 is processed and removed is shown.

When the work is long, the farther away from the center in the longitudinal direction, the greater the frictional force received from the lapping machine (or the longer the friction distance), and the more the work is polished. As a result, a sagged surface shape (see FIG. 6, a 213 processing removal portion) in which both end portions are cut more is obtained.

[0008] The surface shape of the polyurethane pad itself is constantly changing to either concave or convex, and the surface to be processed also changes following the changing surface shape of the polyurethane pad. Therefore, in order to obtain an ultra-high-precision surface, it is necessary to manage the use position and the like of the polyurethane pad.

Under these circumstances, a conventional skilled technician adjusts the processing parameters such as the traverse width of the work holder, the front and rear insertion and removal of the kansashipin, and the rotation speed of the lapping machine in order to obtain the desired surface accuracy. Had been adjusted based on his experience. In addition, when using a pitch polisher, tools for habituation, shaving and correction of the pitch surface are used, and when using a pad polisher, tool correction means such as changing the truing method are taken.

That is, in the conventional high-precision processing of an optical element, the precision and productivity greatly depended on the skill of an operator. In recent years, the shape accuracy required for optical elements has become increasingly severe, and it has become even more difficult to secure and train skilled technicians, so it is increasingly difficult to stably produce products that meet the required accuracy. It has become. In particular, in the above-mentioned polishing of long items, the fact that the work content greatly depends on the skill of the processor has greatly hindered the standardization of work, and so-called standard work books, work guidance marks, etc. However, there is a problem that it is difficult to create a unified one. Along with this, there is a problem that it is difficult to systematically educate from the viewpoint of rearing up.

The present invention does not require special skills,
An object of the present invention is to provide a polishing method capable of obtaining a finished surface having extremely high shape accuracy, and a polishing apparatus used for the method.

[0012]

[Means for solving the problems]
In order to solve various problems in the conventional polishing, the inventor has made intensive studies for a long time. As a result, among various polishing factors, the friction direction between the lapping machine and the work and the movement direction of the conventional polishing plate are changed, that is, the lapping machine rotates in the conventional polishing process, and the workpiece is left and right. He noted that there was a problem in this basic exercise condition.

As shown in FIG. 4 (B), when the workpiece comes to the center of the polisher (polyurethane pad), the large arrow shown in the figure indicates the direction of rotation of the polisher, starting from the center of the workpiece. Both sides of the workpiece are polished from front and rear. This causes the finished surface of the workpiece to have a twisted surface shape. Also, the shape of the workpiece itself is
Since the vertical and horizontal lengths are different, the frictional resistance is large at both ends in the vertical direction, causing edge sagging in the surface shape.

The inventor of the present invention has drastically reviewed the basic form of motion of a conventional lapping machine and has completed the present invention. That is, in the polishing method of the present invention, a reciprocating motion of a sheet-like polishing tool (sheet polisher) is applied to a work surface of a work to polish the work surface, and polishing is performed.
At this time, the pressing of each part of the sheet polisher against the surface to be processed is changed for each part.

Further, the polishing apparatus of the present invention comprises a sheet polisher, a mechanism for reciprocating the sheet polisher (polisher feed mechanism), and means for applying a work surface of a work to a work surface of the sheet polisher (work applying means). )When,
Means for changing the pressing of each part of the sheet polisher against the processing surface for each part (pressing adjusting means).

That is, in the present invention, there is no working force that causes torsion on the work surface. Further, since the polishing tool repeats reciprocation, it is possible to suppress an increase in frictional force (frictional distance) in only one direction. Further, since the pressing of each part of the sheet polisher against the surface to be processed can be controlled, the processing habit (surface habit) of the surface to be processed can be arbitrarily changed.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a front view schematically showing a polishing apparatus according to one embodiment of the present invention. FIG. 2 is a side view of the polishing apparatus of FIG. FIG. 3 is a partial sectional front view showing details of a main part (around a magnetic fluid layer) of the polishing apparatus of FIG.

The polishing apparatus 1 of this embodiment has a sheet polisher 21 forming a large inverted triangular loop. Left and right of the upper side of the sheet polisher 21 are support rollers 31
Is supporting. A driving roller 35 for driving the sheet polisher 21 in the longitudinal direction is provided at a lower end portion of the sheet polisher 21.
(Polisher feed mechanism) is engaged from the inside. The drive roller 35 is driven to rotate by a motor 39 via a timing belt 37. The tension of the sheet polisher 21 can be adjusted by the position of the tension adjusting roller 33 that presses both oblique sides of the sheet polisher 21 inward.

On the upper side of the sheet polisher 21, a work 11 held by a work holder 9 (work applying means) is provided.
Has been applied. The work 11 is fitted into a recess dug in the lower surface of the work holder 9. The work holder 9 is pressed against the sheet polisher 21 by the air cylinder 5 via the rod 7. The base (upper part) of the air cylinder 5 is fixed to the air slide 3. The air slide 3 slides (traverses) left and right in the figure. Therefore, the work holder 9 and the work 11 also traverse left and right. A polishing liquid is supplied from the nozzle 13 to the upper surface of the upper side of the sheet polisher 21, and abrasive grains enter between the upper surface of the sheet polisher 21 and the lower surface (work surface) of the work 11, and polishing of the work surface proceeds.

Below the upper side of the sheet polisher 21, a large number of electromagnets 25 (press adjusting means) are arranged in a matrix. Although not shown, a plurality of electromagnets 25 are also arranged in the width direction of the sheet polisher 21. The coil 27 of the electromagnet 25 is connected to an electromagnet power supply 41. Between the electromagnet 25 and the sheet polisher 21, as shown in an enlarged view in FIG.
3 is provided on one side. The magnetic fluid 23 is stored in a shallow tray 63, and its upper surface is covered with a sheet 61 (rubber, Teflon, or the like). The sheet polisher 21 passes through the upper surface of the sheet 61.

The magnetic field of the electromagnet generated according to the direction of energization of the coil 27 of the electromagnet affects the magnetic fluid 23, and the magnetic fluid 23 above the electromagnet 25 rises upward or dents downward. By this action, the sheet polisher 2
(1) The irregularities on the upper surface can be finely adjusted. The magnetic fluid 2
The reason why the fluid 3 is interposed is that the contact can be softened as compared with the adjusting means having high rigidity.

As shown in FIG. 2, the support roller 31 has both shaft ends supported by a slide 51. The vertical position of the slide 51 can be adjusted by rotating the micrometer head 53, so that the vertical position and the inclination of the support roller 31 and the overall height and inclination of the sheet polisher 21 can be adjusted.

A polishing method using the polishing apparatus of the present embodiment will be described together. An appropriate tension is applied to the sheet polisher 21 to reciprocate left and right in the figure. At that time, basically, the distance between the forward movement and the backward movement is the same. The polishing liquid is dripped from the nozzle 13 onto the sheet polisher 21. The work 11 is put into the recess of the work holder 9, and the lower surface of the work 11 is pressed against the upper surface of the sheet polisher 21. The work 11 is also traversed right and left appropriately. The operation of each electromagnet 25 is controlled by the NC device 43 via the electromagnet power supply 41. Further, the reciprocating motion of the sheet polisher 21 and the traverse of the work holder 9 are also controlled by the NC device 43. As this control method, the past work experience of the same kind of work may be patterned, or a signal from some on-machine shape measuring device may be fed back.

In the polishing method of the present invention,
Reciprocation of the sheet polisher 21 is essential. If only one-way feed is used, the end on the entry side of the polisher will be machined more due to the frictional force between the polisher and the workpiece.
The surface shape becomes defective.

[0025]

As is apparent from the above description, according to the present invention, since the torsion of the surface to be inspected does not occur in principle, high surface accuracy can be easily obtained. In other words, a desired surface accuracy can be obtained without requiring much skilled skill, which was conventionally required during the work, so that the work content can be standardized.

Further, since the precision of tools and the like can be minimized, stable polishing can be performed. Therefore,
Productivity can also be greatly improved.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a polishing apparatus according to one embodiment of the present invention.

FIG. 2 is a side view of the polishing apparatus of FIG.

FIG. 3 is a partial cross-sectional front view showing details of a main part (around a magnetic fluid layer) of the polishing apparatus of FIG. 1;

FIG. 4 is a view showing a main part of a conventional polishing apparatus having a typical pad polisher. (A) is a side view,
(B) is a plan view.

FIG. 5 is a view schematically showing a processing habit of a rod-shaped work in a conventional lapping machine polishing process. (A), (C) is a side view, (B) is a front view.

FIG. 6 is a diagram schematically showing a processing habit (surface droop) of a rod-shaped work in a conventional lapping machine polishing process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Polishing apparatus 3 Air slide 5 Air cylinder 7 Rod 9 Work holder 11 Work 13 Nozzle 21 Sheet polisher 23 Magnetic fluid layer 25 Electromagnet 27 Coil 31 Support roller 33 Tension adjusting roller 35 Drive roller 37 Timing belt 39 Motor 41 Electromagnet power supply 43 NC device 51 Slide 53 Micrometer head 61 Sheet 63 Receiving tray

Claims (5)

[Claims] 1. A sheet-like polishing tool (sheet polisher)
Polishing, while reciprocating the workpiece, and polishing the workpiece by contacting the workpiece surface with the workpiece surface. At this time, the pressing of each part of the sheet polisher against the workpiece surface is changed for each part. Method. 2. A sheet polisher, a mechanism for reciprocating the sheet polisher (polisher feed mechanism), means for applying a work surface of a work to a work surface of the sheet polisher (work applying means), and A means for changing the pressing against the processing surface for each part (pressing adjusting means). 3. The polishing apparatus according to claim 2, wherein said work contact means has a traverse mechanism. 4. The polishing apparatus according to claim 2, wherein said sheet polisher is a loop belt. 5. The pressing adjustment means has a plurality of electromagnets arranged on the side opposite to the processing surface of the sheet polisher, and a magnetic fluid layer arranged between the sheet polisher and the electromagnets. The polishing apparatus according to the above.