JP2006116673A - Concentric groove working method, concentric groove work-piece manufactured by this method and concentric groove molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concentric groove working method to work even a convex curved part in favorable surface roughness while working an sharp groove trough part by using a grinding wheel a head end of which is pointed by working a part a cross-section of which becomes a convex curve by an end surface part of a grinding wheel with a shaft and a part a cross-section of which becomes a straight line by a circumferential surface part of the grinding wheel with the shaft and a concentric groove work-piece to manufacture under this method by working by scanning the grinding wheel while changing inclination of a rotation axis of the grinding wheel with the shaft. <P>SOLUTION: The part the cross-section of which becomes the convex curve is worked by the end surface part of the grinding wheel 4 with the shaft and the part the cross-section of which becomes the straight line is worked by the circumferential surface part of the grinding wheel 4 with the shaft by scanning the grinding wheel 4 with the shaft against the work-piece 1 rotating while changing inclination of a rotation axis 5 of the grinding wheel 4 with the shaft by rotating the work-piece 1 around a center of a concentric groove 2 as the rotation axis in the concentric groove working method to grind and work the concentric groove 2 the cross-section of which are made of the convex curve and the straight line by using the grinding wheel 4 with the shaft. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical component composed of concentric grooves whose cross-sectional shape is a straight line and a convex curve, a concentric groove processing method used for manufacturing a mold for optical components, and a concentric groove processed product manufactured by this method. Is.

Conventionally, as a method of processing a concentric groove shape using a grinding wheel, the grinding wheel with a sharpened tip is driven in the radial direction and the rotation axis direction of the workpiece, and is constituted by a plurality of discontinuous curved surfaces. A method of manufacturing an axially symmetric aspherical part is known (see, for example, Patent Documents 1 and 2).
FIG. 18 is a schematic view showing a grinding wheel having a sharp tip used for processing of a concentric groove shape (corresponding to Patent Document 1). FIG. 19 is a schematic view showing a grinding wheel having a rounded tip used for machining concentric grooves.
In the case of FIG. 18, although the shape of the trough part of a workpiece | work can be sharpened, since the front-end | tip 6 of a tool is sharp, there exists a problem that the surface roughness of a processing surface worsens. As a method for preventing the surface roughness of the processed surface from being deteriorated, there is a method in which the edge 6 ′ of the grinding wheel is rounded as shown in FIG. 19, but in this case, the problem that the shape of the groove is rounded occurs. .
Moreover, there exists a method of forming a grindstone for every ring zone to process like patent document 2. FIG. In the case of this method, it is possible when the groove cross-sectional shape is a straight line, but when the cross-section is a curved shape, there is a problem that it becomes difficult to form a grindstone. Moreover, since a grindstone is formed for each annular zone, it is difficult to process with 100 or more annular zones to be processed.
FIG. 20 is a plan view showing a workpiece having a groove-shaped portion which is an object of the present invention. FIG. 21 is a front view showing a cross section taken along the line aa ′ of FIG. FIG. 22 is an enlarged view showing a circled portion in FIG. 20 and 21, reference numeral 1 indicates a workpiece, and reference numeral 2 indicates a groove.
In FIG. 22, 1′-2, 2′-3, and 3′-4 are upwardly convex curves, and 1-1 ′, 2-2 ′, 3-3 ′, and 4-4 ′ are straight lines. When the groove shown in FIG. 21 is processed, there is a method of processing by driving the grindstone with respect to the workpiece 1 while rotating the workpiece 1 as in Patent Document 1.
FIG. 23 is a schematic view showing a state in which a concentric groove whose cross section is formed by a convex curve and a straight line is processed by a conventional method. FIG. 23 shows the workpiece 1, the groove 2, the rotating shaft 3 of the workpiece 1, the grinding wheel 4, and the rotating shaft 5 of the grinding wheel 4.

FIG. 24 is a schematic view showing a convex curve in a cross section processed by a grinding wheel having a sharp tip. FIG. 25 is a schematic view showing a state in which a sharp tool tip is transferred to a machining surface. When using a grinding wheel with a sharp tip, it is excellent in that the groove can be sharpened. However, when processing a portion where the cross section becomes a convex curve as shown in FIG. 24B, the tool tip is sharp. Therefore, there is a problem that the surface roughness is deteriorated.
FIG. 25 shows a state in which the sharp tool tip is transferred to the machining surface. The ideal machining surface 11 has a shape shown by a dotted line, whereas the actual machining surface 12 is represented by a solid line. As shown, the sharp tool shape is the transferred surface.
As a method of improving the surface roughness of the portion where the cross section is a convex curve, there is a method of rounding the tip of the grindstone as shown in FIG. As described above, FIGS. 18 and 19 show the tip shape of the grinding wheel. 18 shows a grinding wheel having a sharp tip, and FIG. 19 shows a grinding wheel having a rounded tip 6 ′.
As shown in FIG. 19, when a grindstone having a rounded grindstone tip 6 ′ is used, the surface roughness of the portion having a curved cross section is excellent as shown in FIG. There is a problem that the groove valleys as shown cannot be sharpened.
FIG. 26 is an enlarged schematic view showing a portion B in FIG. Reference numeral 13 denotes a groove part. Since the groove valley portion 13 cannot be made smaller than the radius of the tip of the grindstone, when using a grindstone having a rounded tip, there is a problem that the groove valley portion is also rounded.
JP 2000-237942 A JP 2002-321146 A

As described above, the conventional method cannot achieve both the sharp groove valley portion and the surface roughness of the convex curve portion.
In view of the above situation, the object of the present invention is to perform processing by scanning the grinding wheel while changing the inclination of the rotation axis of the grinding wheel with a shaft. The convex curve part is processed while processing the sharp groove valley using a sharpened tip by processing the part where the section becomes a straight line at the circumferential surface part of the grinding wheel with a shaft. Another object of the present invention is to provide a concentric groove processing method for processing with good surface roughness and a concentric groove processed product manufactured by this method.

In order to solve the above-mentioned problem, the invention according to claim 1 is a concentric groove processing method for grinding a concentric groove having a convex curve and a straight section using a grinding wheel with a shaft. Rotating a workpiece with the center as a rotation axis, and scanning the grinding wheel with a shaft with respect to the rotating workpiece while changing the inclination of the rotation axis of the grinding wheel with a shaft, the grinding wheel with a shaft A concentric grooving method is characterized in that a portion having a convex curve at the end face portion is processed at a circumferential surface portion of the shaft-equipped grinding wheel.
The invention according to claim 2 is characterized in that a normal line of a convex curve of a groove section at a groove processing point at which the grinding wheel with a shaft and a concentric groove to be processed come into contact with the rotation axis of the grinding wheel with a shaft. The concentric groove processing method according to claim 1, which is parallel.
The invention described in claim 3 is characterized by the concentric groove machining method according to claim 1, wherein a diamond grinding wheel is used for the shaft-equipped grinding wheel.
According to a fourth aspect of the present invention, the shape of the processed concentric groove is measured, and the concentric groove processing with high accuracy is performed by reflecting the error of the measured groove and performing the groove processing again. It features a concentric groove machining method.
According to the fifth aspect of the present invention, an arc approximate curve having a shape in which the sections of the concentric grooves are convex curves connected to each other is obtained, and a spherical surface whose cross section is equal to the obtained arc approximate curve is processed. The concentric groove processing method according to claim 1, wherein the tool is aligned by measuring an error of the processed spherical surface.
According to a sixth aspect of the present invention, the angle formed by the convex curve portion and the straight line portion of the cross section of the concentric groove is other than a right angle by changing the angle formed by the end surface of the grinding wheel with a shaft and the circumferential surface. The concentric groove machining method according to claim 1, wherein the concentric groove machining is performed.
Further, in the invention according to claim 7, after the concentric groove machining method is carried out, the region that has not been precisely machined is machined by using a grinding wheel edge while tilting the tool rotation axis, thereby forming the concentric groove. The concentric groove processing method according to claim 1, wherein the vicinity of the trough is also shaped accurately.
The invention according to claim 8 is characterized by a concentric groove processed product processed by the concentric groove processing method according to claim 1.
The invention according to claim 9 is characterized by a concentric groove molded product formed by the concentric groove processed product according to claim 8.

  According to the present invention, since the portion where the cross section of the groove becomes a curve is processed at the end surface portion of the grinding wheel with a shaft, processing with excellent surface roughness can be performed even with the edge of the grinding wheel sharpened. Moreover, since the edge of a grindstone is sharp, a sharp groove valley part can be obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view for explaining concentric grooving by the concentric grooving method of the present invention. In FIG. 1, reference numeral 1 is a workpiece, reference numeral 2 is a concentric groove to be processed, reference numeral 3 is a rotation axis of the workpiece 1, reference numeral 4 is a grinding wheel, reference numeral 5 is a rotation axis of the grinding wheel 4, reference numeral 7 is a processing point, Reference numeral 8 indicates a normal line of the curved portion (curved surface portion) 2 a of the concentric groove at the processing point 7.
By making the rotation axis 5 of the grinding wheel 4 parallel to the normal 8 of the curved portion 2a of the concentric groove 2 at the machining point 7, the inclination of the curved portion of the cross section of the concentric groove 2 at the machining point 7 is corrected. Therefore, it is possible to process a groove with an accurate shape.
That is, in this embodiment, in the concentric groove processing method in which the concentric groove 2 having a cross section of a convex curve and a straight line is ground by using the grinding wheel 4 with a shaft, the workpiece 1 with the center 3 of the concentric groove 2 as the rotation axis. , And the workpiece 1 rotating while changing the inclination of the rotary shaft 5 of the shaft-equipped grinding wheel 4 is scanned by the shaft-equipped grinding wheel 4 so that the end surface of the shaft-equipped grinding wheel is convex. A characteristic is that the portion that becomes a curve is processed, and the portion whose cross section is a straight line is processed by the circumferential surface portion (outer peripheral edge portion) of the grinding wheel with shaft.
By using a diamond bite grindstone with excellent sharpness as the grinding grindstone 4, a processed surface with excellent surface roughness and shape accuracy can be obtained. By measuring the processed groove shape and reflecting the measured groove error again, the groove processing can be performed with high accuracy.
In order to machine an accurate concentric groove shape, it is necessary to accurately align the position of the tool. However, when measuring by measuring the concentric groove, the measurement length in each cross section is shortened, so errors are likely to occur. .
Therefore, an arc approximate curve having a shape obtained by connecting the cross-sectional shapes of the concentric grooves 2 is obtained, a spherical surface that is equal to the obtained arc approximate curve is machined, an error of the machined spherical shape is measured, Positioning may be performed.
Further, by changing the angle formed by the end surface of the grinding wheel 4 with a shaft and the circumferential surface thereof, concentric groove processing can be performed in which the angle formed by the convex curve portion 2a and the straight portion 2b of the concentric groove 2 is not a right angle. it can.

FIG. 2 is an enlarged view showing a state in which a portion near the trough portion of the groove is being processed. FIG. 3 is an enlarged view of a region A in FIG. In FIG. 3, reference numeral 14 indicates an ideal shape of the groove. Since the end face of the grinding wheel 4 is a straight line, an unprocessed region is generated as indicated by the hatched portion 15 in FIG.
FIG. 4 is an enlarged view for explaining an unprocessed region in FIG. As shown in FIG. 4, by processing the aa ′ portion where the unprocessed region is generated using the tip portion 6 of the grinding wheel 4, groove processing closer to the ideal shape can be performed.
FIG. 5 is a schematic perspective view showing an example of the configuration of a processing machine used in the processing method of the present invention. In FIG. 5, the workpiece 21 is placed on the workpiece rotating shaft 23 so as to face the grinding wheel 24 with a shaft. FIG. 5 shows a tool rotating shaft 25 and a C-axis rotating shaft 26.
The processing machine has three axes of X, Y, and Z orthogonal and four axes of C axis. In FIG. 5, an X-axis stage 27, a Y-axis stage 28, a Z-axis stage 29, and a C-axis table 31 are shown. Further, the workpiece 21 is supported by the workpiece spindle 30 and rotates about the workpiece rotation shaft 23.
The grindstone with shaft 24 is rotated around the rotation shaft 25 of the grindstone with shaft 24 by the tool spindle 32. Although the workpiece rotation axis 23 is always parallel to the Y axis, the tool rotation axis 25 can change the inclination with respect to the Y axis on the XY plane by the rotation of the C axis table 31.
FIG. 6 is an enlarged schematic perspective view of a portion of FIG. 5 showing a state of concentric groove processing. In FIG. 6, reference numeral 22 indicates a groove processed into the workpiece 21. The same parts as those in FIG.
7 and 8 are schematic views for explaining a procedure for performing concentric groove processing. Groove machining is performed in the order of A → B → C → FIG. In FIG. 7, a workpiece 21 is a workpiece on which grooving is performed, and shows a processed groove 22 and a hatched portion 35 that is a region that has not yet been processed. The rotation axis of the grindstone is indicated by reference numeral 36.
In FIG. 7, the procedure A shows a state immediately after the first grooving is started, and the procedure B shows a state that the first grooving is finished soon. The dotted line indicates the grindstone position in procedure A. As shown in the figure, the grindstone 24 is moved while the inclination of the rotation shaft 36 of the grindstone 24 is changed so that the normal line of the groove 22 at the machining point and the rotation axis of the grindstone 24 are parallel.
Procedure C shows a state where the second groove is being processed. As with the first groove, machining is performed by moving the grindstone 24 while changing the inclination of the rotation axis 36 of the grindstone 24 so that the normal of the groove at the machining point and the rotation axis of the grindstone are parallel. The same processing as the third and fourth is repeated. FIG. 8 shows a state in which the grooving is finished soon.

FIG. 9 is a schematic diagram showing the measurement of the amount of deviation from the ideal shape of the groove processed in each region of the concentric groove. After processing the groove, as shown in FIG. 9, the amount of deviation from the ideal shape of the groove processed in each region of the groove is measured. FIG. 9 shows only one side of the processed surface. Since processing is rotationally symmetric, usually only one side needs to be measured.
FIG. 10 is a graph showing an example in which the amount of deviation from the ideal shape in the region 1-1 ′ of FIG. 9 is measured. FIG. 11 is a graph showing the result of 6th-order polynomial approximation of the deviation from the ideal shape shown in FIG.
The expression of the sixth-order polynomial approximation shown in FIG. 11 is expressed as E (x). In the case of FIG. 11, approximation is performed with the sixth order, but the order of the polynomial is not limited to the sixth order, and a more suitable order can be selected depending on the shape of the workpiece, the error curve pattern, and the like.
FIG. 12 is a schematic view showing the cross-sectional shape of the groove of the portion 1-1 ′ in FIG. 9 in a graph. It is assumed that the cross-sectional shape of the groove can be defined by the formula f (x). When the groove is reworked, the groove can be machined with higher accuracy by operating the tool so as to machine the shape that can be defined by the equation of f (x) -E (x).
FIG. 13 is a graph showing the amount of deviation from the ideal shape of the groove that has been grooved again with the error reflected. It can be seen that the machining can be performed with high accuracy by reflecting the error of the machining performed first in the next machining.
FIG. 14 is a schematic view showing a concentric groove shape to be processed. In FIG. 14, the groove shape 37 shows a line 38 obtained by connecting the curved groove portions of the grooves, and a line 39 obtained by calculating an arc approximation curve of the curve of the line 38. A spherical shape whose cross section is a line 39 is processed, the error of the spherical surface is measured, and the tool is aligned from the obtained error.
FIG. 15 is a schematic view showing, in the first embodiment, a state in which the angle of the cross section of the concentric groove to be processed is changed by changing the angle a formed by the end face of the grindstone of the tool and the circumferential surface.
FIG. 16 is a schematic view showing, in the second embodiment, how the angle of the cross section of the groove to be machined is changed by changing the angle b formed between the end face of the grindstone of the tool and the circumferential surface. FIG. 17 is a schematic view showing, in the third embodiment, how the angle of the cross section of the groove to be machined is changed by changing the angle c formed between the end face of the grindstone of the tool and the circumferential surface.
FIG. 15 shows a state of processing a groove whose cross section is an acute angle, FIG. 16 shows a state of processing a right angle groove, and FIG. 17 shows a state of processing a groove whose cross section is an obtuse angle. . 15 to 17, reference numeral 4 denotes a grinding wheel.

ADVANTAGE OF THE INVENTION According to this invention, the concentric groove process which has the processed surface excellent in surface roughness and has a sharp trough part can be performed. Since the inclination of the curved surface at the processing point can be made correct, concentric grooves with an accurate shape can be formed.
According to the present invention, a machined surface having excellent surface roughness and shape accuracy can be obtained. Since tool positioning can be performed accurately, highly accurate concentric groove processing can be performed. Further, it is possible to perform groove processing in which the angle formed by the curved portion and the straight portion of the concentric groove is not a right angle.

It is the schematic explaining the concentric groove processing by the concentric groove processing method of this invention. It is an enlarged view which shows a mode that the place near the trough part of a groove | channel is processed. It is an enlarged view of the area | region of A of FIG. It is an enlarged view explaining the unprocessed area | region of FIG. It is a schematic perspective view which shows an example of a structure of the processing machine used for the processing method of this invention. It is the schematic perspective view which expanded one part of FIG. 5 which shows the mode of concentric groove processing. It is the schematic explaining the procedure which performs a concentric groove process. It is the schematic explaining the procedure which performs a concentric groove process. It is the schematic which shows the measurement of the deviation | shift amount from the ideal shape of the groove | channel processed in each area | region of a concentric groove | channel. It is a figure which shows the example which measured the deviation | shift amount from the ideal shape in the 1-1 'area | region of FIG. 9 with a graph. It is a figure which shows the result of having performed the 6th-order polynomial approximation about the deviation | shift amount from the ideal shape shown in FIG. It is the schematic which shows the cross-sectional shape of the groove | channel of the 1-1 'part of FIG. 9 with a graph. It is a figure which shows the deviation | shift amount from the ideal shape of the groove | channel which performed the groove processing again reflecting an error with a graph. It is the schematic which shows the concentric groove shape which processes. It is the schematic which shows a mode that the angle of the cross section of the concentric groove | channel processed is changed in 1st Embodiment by changing the angle which the end surface of the grindstone of a tool and the circumferential surface make. It is the schematic which shows a mode that the angle of the cross section of the groove | channel processed is changed in 2nd Embodiment by changing the angle which the end surface of the grindstone of a tool and the circumferential surface make. It is the schematic which shows a mode that the angle of the cross section of the groove | channel processed by changing the angle which the end surface of the grindstone of a tool and a circumferential surface change changes in 3rd Embodiment. It is the schematic which shows the grinding wheel which has the sharp tip used for processing of a concentric groove shape. It is the schematic which shows the grinding wheel which has a round front end used for processing of concentric groove shape. It is a top view which shows the workpiece which has the groove-shaped part which is the object of this invention. It is a front view which shows the cross section in a-a 'of FIG. It is an enlarged view which shows the part enclosed with the circle in FIG. It is the schematic which shows a mode that the concentric groove | channel where a cross section consists of a convex curve and a straight line is processed by the conventional method. It is the schematic where the cross section processed with the grinding wheel which has a sharp tip shows a convex curve. It is the schematic which shows a mode that the sharp tool front-end | tip is transcribe | transferring to the process surface. It is the schematic which expands and provides the part of B of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Workpiece, 2 Concentric groove, 3 Rotating axis of workpiece 1, 4 Grinding wheel with 4 axes, 6 Tip of grinding wheel 4 Rotating axis of grinding wheel 4 (tool rotating axis), 7 machining points, 8 machining points Normal of curve of concentric groove 2 in 7, 21 workpiece, 24 grinding wheel with shaft

Claims (9)

  In a concentric groove machining method for grinding a concentric groove having a convex curve and a straight section using a grinding wheel with a shaft, the workpiece is rotated with the center of the concentric groove as a rotation axis, and the grinding wheel with the shaft is rotated. By scanning the grinding wheel with a shaft on the rotating workpiece while changing the inclination of the shaft, the end surface portion of the grinding wheel with a shaft processes a portion whose cross section becomes a convex curve. A concentric grooving method characterized in that a portion having a straight cross section is processed by a circumferential surface portion of a grinding wheel.   The normal line extending from the convex curve of the groove cross-section at the groove processing point at which the grinding wheel with shaft and the concentric groove to be processed contact with the axis of rotation of the grinding wheel with shaft is parallel. The concentric groove processing method according to 1.   The concentric groove processing method according to claim 1, wherein a diamond grindstone is used as the shaft grinding grindstone.   The concentric groove processing method according to claim 1, wherein the concentric groove processing with high accuracy is performed by measuring the shape of the processed concentric groove and performing the groove processing again by reflecting an error of the measured groove.   Obtain an arc approximate curve with a shape where the sections of each concentric groove are convex curves connected to each other, process a spherical surface whose cross section is equal to the obtained arc approximate curve, and measure the error of the processed spherical surface The concentric groove processing method according to claim 1, wherein the tool is aligned by the above-described method.   By changing the angle formed by the end face of the grinding wheel with a shaft and its circumferential surface, concentric groove processing is performed in which the angle formed by the convex curve portion and the straight line portion of the cross section of the concentric groove is not a right angle. The concentric groove processing method according to claim 1.   By processing the region that has not been accurately processed after the concentric groove processing method is performed using the grinding wheel edge while tilting the tool rotation axis, the vicinity of the valley portion of the concentric groove is also accurately shaped. The concentric groove processing method according to claim 1.   A concentric groove processed product processed by the concentric groove processing method according to claim 1.   A concentric groove molded product, wherein the concentric groove processed product according to claim 8 is formed.

Images