JPH03117551A - Lens machining method and core-removing grindstone for lens machining - Google Patents

Abstract

PURPOSE:To machine a lens having good core accuracy at a low cost by dividing machining in which grinding of peripheral side section on CG machining face side and grinding of chamfering section are carried out simultaneously into two times machining on the first face side and the second face side of the lens. CONSTITUTION:A lens 5 which is mounted to the tip of a workpiece spindle 4 is rotated to approach the workpiece spindle 4 relatively to a CG tool spindle 8 so that CG machining on a first face side is carried out by a CG grindstone 9. At the same time with this CG machining, a core-removing grindstone 13 is forced to make contact with the lens 5 to perform grinding on a peripheral side section 5a of the first face side and chamfering section. After this, CG machining on a second face side is carried out by matching optical axis of the lens to rotating axis of the workpiece with the spherical section 5c on the already machined first face side and the peripheral side section 5a balanced each other. At the same time with this, a core-removing grindstone 14 is forced to make with the lens 5 to grind a peripheral side section 5d and a chamfering section 5e on the second face side which are left as not ground when the first face side is machined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens processing method and a centering grindstone for lens processing.

[Conventional technology]

Conventional lens grinding includes optical functional surface creation grinding (hereinafter referred to as CG processing), circumferential surface grinding performed after CG processing, chamfer grinding, etc.
G machining, circumferential surface grinding, etc. were generally performed independently and in separate processes. Conventional examples of performing these processing methods simultaneously or consecutively include, for example,
Publication No. 47669 (Conventional Example 1), JP-A-62-1526
64 (Conventional Example 2), Japanese Unexamined Patent Publication No. 59-192449 (Conventional Example 3), and the like are known.

The lens processing methods of Conventional Examples 1 and 2 perform chamfering and grinding in addition to CG processing.

On the other hand, the lens grinding machine of Conventional Example 3 performs circumferential side grinding in addition to CG processing, and in addition to the CG grindstone, a circumferential side grinding wheel is provided on the outer periphery of the lens so as to be able to come into contact with and separate from it.

However, the above three conventional examples propose processing methods in which CG processing and chamfer grinding, or CG processing and circumferential side grinding are performed simultaneously or continuously.

[Problem to be solved by the invention]

However, JP-A No. 59-192449 (Conventional Example 3)
) The peripheral side grinding process seen in
This process is completed by performing CG processing on either side simultaneously or continuously. That is, 1
The idea is that the entire outer periphery of the lens, or the entire outer periphery and the chamfered portions on both sides, are processed by the second grinding process.

According to this method, for example, in chucking, which is commonly used as a lens holding means, the peripheral side of the lens is used to hold the lens, so in the above processing, the lens holding member and the peripheral side grinding wheel are will interfere with each other, making it impossible to implement. Therefore, as a lens holding means, it is necessary to use a pasting method or a spherical part holding method, but these methods are more complicated than the above-mentioned chucking and are not sufficient from the standpoint of reducing man-hours.

The present invention has been made in view of such conventional problems, and the simultaneous processing of lens CG processing and grinding of the circumferential side surface and chamfered portion is divided into two times, one on the first surface side and one on the second surface side. Thus, the present invention aims to provide a lens processing method and a centering grindstone for lens processing, which can reduce the cost of lenses by shortening the processing steps, regardless of which lens holding means is used.

[Means and effects for solving the problem] In order to achieve the above object, the present invention provides a rotatable work spindle unit having a mechanism for holding a lens, which is a workpiece, at the tip of the shaft, and A CG tool spindle unit is provided with a CG grindstone removably attached to the part thereof, and is rotatable and can be moved relatively close to and separated from the tip of the work spindle; In the lens adding system, which is composed of a centering tool spindle unit in which the grinding section can approach and separate from the tip of the work spindle, the work spindle and the CG tool spindle are rotated while rotating the lens attached to the tip of the work spindle. CG processing is performed on the first surface side using a CG grindstone while the CG grindstones are brought relatively close to each other, and at the same time as this CG processing, a centering grindstone is brought into contact with the lens to grind the circumferential side portion and chamfered portion of the first surface side. After machining, the spherical part and circumferential side part on the first surface side which have already been machined are set at opposition (positioning reference position: opposition), so that the lens optical axis and the workpiece rotation axis are aligned. , CG processing is performed on the second surface side, and at the same time as this CG processing, a centering grindstone is brought into contact with the lens to grind the circumferential side portion and chamfered portion of the second surface side that were left uncut during processing on the first surface side. It is characterized by performing the following.

The centering whetstone is composed of a circular plate, and grindstone parts are provided on the outer periphery and end face of both sides of the plate to reduce the number of grindstones during grinding, thereby reducing costs. This is what I did.

〔Example〕

(First Embodiment) Fig. 1 shows a schematic diagram of a lens adding system for explaining the first embodiment of the present invention, Fig. 2 a shows processing on the first surface side, and Fig. The state of side machining is shown respectively.

In FIG. 1, the lens adding system is roughly composed of a work spindle unit 1, a CG tool spindle unit 2, and a centering tool spindle unit 3.

The work spindle 4 of the work spindle unit 1 is provided with a lens holder 6 that removably holds a lens 5 at its shaft end. Also, work spindle 4
is rotatably provided in the direction of arrow A (around the axis), and is supported by the work spindle support 7 so as to be movable in the direction of the arrow (in the axial direction).

An optical functional surface grinding wheel 9 for grinding the optical functional surface of the lens 5 is detachably attached to the CG tool spindle 8 of the CG tool spindle unit 2 at its shaft tip. Further, the CG tool spindle 8 is moved in the direction of arrow C (
The CG tool is provided so that it can rotate freely around the axis (around the axis), and is movable so that the axis of the work spindle 4 (which coincides with the optical axis of the lens 5) and the axis of the CG tool spindle 8 are always in the same plane. It is supported by a spindle support 10. That is, the CG tool spindle 8 is
It is swingable in the direction of arrow 2 with the center of the lens 5 as the swing center within a plane including the axis of the work spindle 4 (in the horizontal plane in FIG. 1), and in the direction of arrow 2, which is perpendicular to the axis. It is provided so that it can move freely in a straight line in the direction of.

The grindstone 9 for grinding an optical functional surface has a generated cutting edge diameter that is approximately 20 to 30% larger than the radius of the lens 5.

As shown in FIGS. 1 and 2, the core number retooling spindle 12 of the centering tool spindle unit 3 has a disc-shaped outer peripheral grinding wheel for grinding the outer peripheral part of the lens 5 on the outer peripheral part of its axis. 13 is detachably attached. Also,
The centering tool spindle 12 is provided rotatably in the direction of the arrow (around the axis), and is parallel to the optical axis of the lens 5 and in the direction of the arrow G (axial direction) and the direction of the arrow C (the lens 5 in the radial direction, in this example, the vertical direction)
Each is movable.

FIG. 2a shows the state of machining on the first side.

The centering grindstone 13 is attached to the peripheral side surface portion 5a of the lens 5 on the first surface side.
It is composed of a circumferential side grindstone 13a for grinding the surface, and a flattening grindstone 13b for grinding the flattened portion 5b.

In order to process the lens 5 using the lens grinding machine equipped with the centering grindstone 13 having such a configuration, first, the work spindle 4, the CG tool spindle 8, and the centering tool spindle 12 are rotated, and the work spindle 4 is rotated. is moved forward in the axial direction to bring the lens 5 into contact with the optical functional surface grinding wheel 9, and the centering tool spindle 12 is moved to touch the peripheral side grindstone 13a of the centering grindstone 13.
Then, the flat grinding wheel 13b is attached to the peripheral side surface 5a of the lens 5.
and is brought into contact with the flattened portion 5b. Then, the processing cutting speed is set to 1 to 61111/sin, and the lens 5
Grinding processing (CG processing and centering processing) is performed on the optical functional surface 5c, peripheral side surface 5a, and flattened portion 5b.

After that, when the predetermined cutting process is completed, spark-out grinding begins. After spark-out grinding is completed, the work spindle 4 is moved backward in the axial direction to separate the lens 5 from the grindstone 9 for grinding optical functional surfaces, and the centering tool spindle 12 is moved to move the centering grindstone 13 to the lens 5.
The first surface side machining is completed.

Figure 2 shows the machining state of the second side.

The lens is held by the chuck claw 6a and the abutment ring 6b, which are lens holders, with the already processed circumferential side surface 5a and the spherical surface 5C of the lens 5, which has been processed on the first surface side, facing each other. The holder is made with high precision so that the optical axis of the chucked lens and the rotational axis of the workpiece coincide.

The centering grindstone 14 is attached to the peripheral side surface portion 5d on the second surface side of the lens 5.
It is composed of a circumferential side grindstone 14d for grinding the chamfered portion 5e, and a chamfering grindstone 14e for grinding the chamfered portion 5e.

Hereinafter, the circumferential side surface 5d, chamfered portion 5e, and spherical surface portion 5f on the second surface side are processed using the same procedure as the first surface side processing.

As described above, according to this embodiment, a lens with good core accuracy can be ground without increasing processing steps or unnecessary man-hours even by the holding method using a chuck using the outer periphery.

In addition, what is shown in FIG. 3 is one in which the tip shapes of the centering grindstone used for the first surface side and the second surface side are provided on the front and back surfaces of a single grindstone. In the figure, 15a corresponds to the circumferential side grindstone 13a, 15b corresponds to the flat grindstone, 15d corresponds to the circumferential side grindstone 14d, and 15e corresponds to the chamfered grindstone 14e. With a grindstone having such a configuration, one grindstone is required for each lens component, which is effective in terms of cost and management.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention. This shows a method for machining a rack having a step on its circumferential side.

The processing means is generally the same as in the first embodiment, and will therefore be briefly described.

First, as shown in FIG. 4a, the first surface side is processed.

That is, the spherical part 5c is ground by a CG grindstone (not shown), and at the same time, the circumferential side grindstone 13a part of the centering grindstone 13 and the plane centering grindstone 13b part are ground by the first grindstone.
It is brought into contact with the circumferential side parts 5a and 5b on the surface side, and at a cutting speed of 1 to 6 (m/wr*n), as shown in FIG. Grind to.

Next, as already shown in FIG. 4, processing is performed on the second surface side, that is, the spherical surface portion 5f is ground using a CG grindstone (not shown), and at the same time, the circumferential side grindstone 1 of the centering grindstone 14 is processed.
The circumferential side surface portion 5d and the stepped taper portion 5g on the second surface side are ground by the portion 4d and the grinding wheel 14g of the stepped portion.

As described above, it is possible to grind the spherical part, circumferential side part, stepped taper part, and chamfered part of a lens having a step.

If we try to finish a lens with a complex-shaped circumferential side surface like the one in this example with one circumferential side grinding process and a chamfer grinding process, the cutting edge shape of the centering grindstone will have to be quite complex. This results in poor compatibility with other parts. Furthermore, with a grindstone having such a cutting edge shape, the cutting direction is limited to only the direction perpendicular to the grindstone axis, and according to such a processing method, the There is a high possibility that the parts will be chipped.

According to this embodiment, the above-mentioned problem can be solved by dividing the process into two parts, so that the shape of the tip of the grinding wheel is simple, consisting of a flat part and a tapered part, which makes it easy to use with other parts. This makes it possible to grind in the direction of the cut, and processing can be performed without the problem of chipping.

(Third Embodiment) FIG. 6 shows a third embodiment of the present invention. This example relates to a centering grindstone used in the method of the present invention. The centering whetstone 13 is composed of a circular plate body, and has whetstone parts 13a and 13d used for grinding the circumferential side of the circular plate body and whetstone parts 13b and 13e used for chamfering grinding process. It has a symmetrical shape with respect to the plane cut perpendicular to it.

An example of lens processing using this grindstone is shown below.

In FIG. 6a, processing is performed on the first surface of the lens.

The lens 5 is provided with an edge portion 15 to increase the width of the circumferential side portion on the convex side.
A chuck pawl 6a5 and a stopper, which are lens holders, are held by the ring 6b by the circumferential side surface portion of the lens 5 and the outer circumferential plane portion of the convex portion side.

Then, in this state, the spherical surface part 5c is ground by the CG grindstone 9, and at the same time, the circumferential side surface part 5a and the chamfered part on the first surface side are ground by the circumferential side grindstone part t3a and the chamfered part 13b of the centering grindstone 13. Grind 5b.

Next, as already shown in FIG. 6, processing is performed on the second surface of the lens. The lens 5 is held by lens holders 6a and 6b using the circumferential side surface portion 5a and the spherical surface portion 5C which were ground in the first surface side processing, and the CG grindstone 9
The spherical portion 5r is ground by the following steps. In this CG processing, the lens edge portion 15 left in the first surface side processing is
is removed and there is no need to chamfer the second surface of the lens, so in the second surface processing, grinding of the circumferential side surface and the chamfer is not performed.

As in this embodiment, in a lens in which the grinding of the peripheral side surface and the outer peripheral part is completed during processing of the first surface, if the front and back sides of the centering grindstone are made to have the same shape, Turn over the centering whetstone 13, and the whetstone part 13d,
It is also possible to carry out the above processing using the grinding wheel 13e, which results in twice the effect on the life of the grindstone.

〔Effect of the invention〕

As described above, according to the lens processing method according to the present invention, regardless of the lens holding method, it is possible to perform CG processing and machining of the circumferential side and chamfered parts at the same time, and a lens with good center accuracy can be produced at a low cost. It is now possible to process.

Furthermore, according to the centering grindstone of the present invention, even in the lens processing method described above, only one centering grindstone is required for one lens component, which is effective in terms of cost and management. It is.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a schematic diagram, FIGS. 2(a) and (c) are explanatory diagrams of the first embodiment, and FIG. 3 is an illustration showing another embodiment of the centering grindstone. Part side view, FIG. 4(a). (b) is an explanatory diagram of the second embodiment, and FIG. 5 is an explanatory diagram showing the relationship between the lens and the grindstone. Figure 6(a). (b) shows the third embodiment 1...Work spindle unit 2...CG tool spindle unit 3...Number of cores retool spindle unit 4...Work spindle 5...Lens 6...Lens holding Tool 7... Work spindle support 8... CG tool spindle 9... Grinding wheel 10... CG tool spindle support 12... Centering tool spindle 13... Centering grindstone

Claims (2)

[Claims] (1) A rotatable work spindle unit having a mechanism for holding a lens, which is a workpiece, at the tip of the shaft, and a grinding wheel for creating the spherical surface of the lens removably installed at the tip of the shaft, which is rotatable and A CG tool spindle unit that can be moved relatively close to and separated from the tip of the work spindle, and a grindstone for grinding the outer periphery of the lens and the chamfered portion (
A centering grindstone) is provided removably and rotatably,
Generative grinding of the optical functional surface of a lens is performed by the above-mentioned spherical surface generating grinding wheel using a lens processing device comprising a centering tool spindle unit in which a whetstone grinding section can move relatively close to and away from the tip of the work spindle. The first lens
A lens processing method characterized in that processing is carried out in two steps: one on the surface side and one on the second surface side. (2) The grinding wheel (centering grindstone) for grinding the circumferential side part and chamfer part in lens processing is composed of a circular plate, and the outer peripheral part and end face on one side of the circular plate shape and the opposite side A centering grindstone for lens processing, characterized in that a grindstone part is provided on the outer circumferential part of the surface side and the end face part.