JP2009160714A - Manufacturing method for die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a die with high accuracy and high curvature while preventing interference between the die and a grinding wheel. <P>SOLUTION: This method includes processes of: coarsely processing into a recess surface; and finishing the coarsely processed surface that is coarsely processed by means of grinding, using the columnar grinding wheel 10. During the finishing process, when the curvature radius of the high curvature die 1 is taken as R, and the diameter of the grinding wheel 10 is taken as D, D/2<R is satisfied. When the inclination angle between the rotational center shaft of the high curvature die and the grinding wheel is taken as θ, the interference length between the high curvature die 1 in the depth direction and the grinding wheel 10 is taken as ΔZ, the deflection amount of the grinding wheel 10 in the diametrical direction is taken as α, the deflection amount of the grinding wheel 10 in the lengthwise direction is taken as β, the clearance portion dimension of the grinding wheel 10 in the diametrical direction is taken as ΔY, and the clearance portion dimension of the grinding wheel 10 in the lengthwise direction is taken as ΔX, the grinding wheel 10 where the clearance portion 14 satisfying ΔY=ΔZcosθ+α, and ΔX=2ΔZsinθ+2β is formed at least in a portion that interferes with an edge of the high curvature die 1, is used during grinding. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a mold having a concave surface with a strong curvature.

In recent years, with an increase in capacity and performance of an optical disk device, an aspheric optical lens having a high aperture ratio (NA) tends to be used. A lens molding die for molding such an optical lens needs to be formed into a concave shape having a deep depth and a strong curvature. In addition, with the miniaturization of the optical disk device, the optical lens is also reduced in diameter.
In such a lens mold, an aspherical concave surface is roughly machined in a hard and brittle material such as cemented carbide or SiC, and then the roughened surface is ground to a desired shape accuracy and surface roughness. Processing.
For example, in the grinding apparatus shown in Patent Document 1, the workpiece to be ground, the grinding stone, and the like are provided by providing a cylindrical grinding wheel in an arrangement inclined at a predetermined angle with respect to the rotation center axis of the workpiece. It is possible to reduce interference (contact). For this reason, there has been disclosed a grinding apparatus capable of setting the grinding wheel shaft thick and improving the processing accuracy by improving the rigidity.

JP 2005-319554 A

However, when the opening diameter of the mold is reduced and the concave mold having a strong curvature is processed, the grinding wheel may be disposed at a predetermined angle with respect to the rotation center axis of the workpiece to be ground. There is a problem that the grinding wheel and the edge of the mold come into contact with each other and cannot be processed into the designed shape.
For example, when the die is subjected to cross grinding by normal control, the positional relationship between the die and the grinding wheel as shown in FIG. 10 may be obtained. The grinding wheel 110 includes a shaft portion 111 and a grinding wheel portion 112, and the grinding wheel portion 112 of the grinding wheel 110 and the edge of the mold 101 interfere with each other when the concave surface 105 is ground. For this reason, the edge of the mold 101 is ground and cannot be processed into a desired design shape.
In FIG. 10, the cylindrical grinding wheel 110 is disposed so as to be inclined at an angle of 45 ° with respect to the rotation center axis of the mold 101, and this angle minimizes the interference of the grinding wheel 110 with the mold 101. Although it is an arrangement, the diameter of the grindstone portion 112 must be reduced in order to eliminate interference. However, if the diameter of the grindstone 112 is reduced, there is a problem that the rigidity of the grinding grindstone 110 is reduced, causing vibrations and accurate grinding cannot be performed. The concave surface has a deep mold and a strong curvature. There is a limit to shape grinding.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] This application example is a method for manufacturing a mold, in which a step of roughing a concave surface and the roughened roughened surface are finished by grinding using a cylindrical grinding wheel. In the finishing step, when the radius of curvature of the mold is R and the diameter of the grinding wheel is D, the relationship is D / 2 <R, and the rotation of the mold The inclination angle between the central axis and the grinding wheel is θ, the interference length with the grinding wheel in the depth direction of the mold is ΔZ, the deflection amount in the radial direction of the grinding wheel is α, the length direction of the grinding wheel When the deflection amount is β, the clearance dimension in the radial direction of the grinding wheel is ΔY, and the clearance dimension in the length direction of the grinding wheel is ΔX, at least at the edge of the mold during grinding In the interfering part, the relief part of ΔY = ΔZcosθ + α and ΔX = 2ΔZsinθ + 2β The formed grinding wheel is used.

  According to this manufacturing method, the opening diameter of the mold is reduced, and even in the processing of a concave mold having a strong curvature, the edge of the mold does not interfere with the grinding wheel in the grinding process in the finishing process, Designed shape can be processed with high accuracy. Further, according to the manufacturing method of this application example, by forming the relief portion on the grinding wheel, it is possible to obtain a grinding wheel that does not significantly reduce the rigidity, and the degree of freedom of processing is improved and the strength is high. A method of manufacturing a curvature mold can be provided.

  Application Example 2 In the mold manufacturing method according to the application example described above, it is preferable that the grinding wheel is a resin-bonded grinding wheel using diamond abrasive grains.

  According to this manufacturing method, high precision processing is possible by using diamond abrasive grains, and since the bonding material of diamond abrasive grains is a resin, scratches are difficult to enter on the surface of the grinding process, and the surface roughness is reduced. It is possible to finish it in a good surface state without causing it.

  Application Example 3 In the mold manufacturing method according to the application example, the roughing process is grinding using the grinding wheel, the radius of curvature of the mold is R, and the diameter of the grinding wheel is D. Where D / 2 <R, the inclination angle between the rotation center axis of the mold and the grinding wheel is θ, and the interference length with the grinding wheel in the depth direction of the mold is ΔZ. , Α is the amount of runout in the radial direction of the grinding wheel, β is the amount of runout in the length direction of the grinding wheel, ΔY is the size of the relief portion in the radial direction of the grinding wheel, and the size of the relief portion in the length direction of the grinding wheel Is set to ΔX, it is desirable to use the grinding wheel in which relief portions of ΔY = ΔZcosθ + α and ΔX = 2ΔZsinθ + 2β are formed at least in a portion that interferes with the edge of the mold during grinding.

  According to this manufacturing method, grinding can be performed even in the roughing of the concave surface, and a strong curvature die can be manufactured using the same apparatus for roughing and finishing. Therefore, the versatility of the manufacturing apparatus can be improved, and an efficient strong curvature mold can be manufactured.

  Application Example 4 In the method for manufacturing a strong curvature mold according to the application example described above, it is preferable that a finishing polishing process is included after the finishing process.

  According to this manufacturing method, the surface roughness of the concave surface of the high-curvature mold is improved by finish polishing, and a high-precision and high-rigidity mold can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings.
(First embodiment)

FIG. 1 is a configuration diagram showing a schematic shape of a strong curvature mold for an optical lens. FIG. 1 (a) is a schematic plan view, and FIG. 1 (b) is a schematic diagram taken along the line AA in FIG. It is sectional drawing.
A strong curvature mold 1 for an optical lens is formed by processing a concave surface 5 from a cylindrical cemented carbide. This strong curvature mold 1 has a relationship of Z ≧ X, where X is the radius in the caliber direction of the strong curvature mold 1 and Z is the depth dimension of the strong curvature mold 1. The concave surface 5 is axisymmetric and formed in an aspherical shape, and the surface roughness PV is finished to 0.1 to 0.3 μm.

Here, the strong curvature will be described. FIG. 9 is an explanatory diagram for explaining the strong curvature.
FIG. 9 shows a state in which the curved surface of the optical lens 35 molded using a mold is measured. In the present embodiment, an angle formed between a tangent and a surface parallel to the bottom surface (reference surface) of the optical lens 35 when the measurement probe 36 is brought into contact with the curved surface of the optical lens 35 is referred to as a measurement surface inclination angle θ _S. A lens having a curved surface having a measurement surface inclination angle θ _S of 60 ° or more and less than 90 ° is defined as a strong curvature lens. A mold for molding a strong curvature surface such as the strong curvature lens is called a strong curvature mold.

Next, a method for manufacturing a strong curvature mold will be described.
FIG. 2 is a flowchart showing a manufacturing process of a strong curvature mold in the first embodiment. FIG. 3 is an explanatory diagram showing the grinding wheel and the radius of curvature of the mold in the first embodiment, and shows the positional relationship between the mold and the grinding wheel in a horizontal section passing through the tip of the grinding wheel. FIG. 4 is an explanatory view for explaining the formation of the grinding wheel in the first embodiment. FIGS. 5A and 5B are explanatory views for explaining the positional relationship between the mold and the grinding wheel in the first embodiment, FIG. 5A is a positional relationship diagram, and FIG. 5B is the details of the relief portion of the grinding wheel. It is an enlarged view shown. FIG. 8 is a block diagram showing the configuration of the grinding machine, FIG. 8 (a) is a schematic side view, and FIG. 8 (b) is a schematic plan view.

Hereafter, the manufacturing process of a strong curvature metal mold | die is demonstrated later on according to the flowchart of FIG.
First, a mold is designed based on the specifications of the optical lens (step S1). Then, rough machining of the concave surface is performed on the cemented carbide by electric discharge machining (step S2). In this process, although the concave surface has a rough surface, the processing is performed to the shape shown in FIG.

Next, in order to perform grinding on the concave surface formed in step S2, truing and shaping of the grinding wheel are performed (step S3).
As shown in FIG. 3, the grinding wheel 10 includes a cylindrical grindstone portion 12 and a shaft portion 11 that fixes the grindstone portion 12. When the diameter of the grindstone 12 of the grinding wheel 10 is D and the radius of curvature of the concave surface of the strong curvature die 1 is R, the diameter D of the grindstone 12 that satisfies the relationship D / 2 <R is selected. This is because when the grinding wheel 10 is processed so as to be inclined at an angle of 45 ° with respect to the rotation center axis of the strong curvature mold 1, when D / 2> R, the strong curvature mold 1 and the grinding wheel This is because of interference. For this reason, the diameter D of the grindstone 12 needs to satisfy the condition of D / 2 <R, and this relationship is all normal when controlling the concave surface 5 of the strong curvature mold 1 by controlling the normal line. This holds true. In addition, the larger the diameter of the grindstone portion 12, the greater the rigidity, and less change in the grindstone shape due to wear. For this reason, it is advantageous that the diameter of the grindstone 12 is larger in order to perform grinding with high accuracy. Considering these things, the diameter D of the grindstone 12 is selected.
The grindstone 12 is a resin-bonded grindstone (grain size of about # 3000) using diamond abrasive grains and using a polyimide resin or a phenol resin as a binder.

Next, a process called truing is performed in order to form the outer periphery of the grindstone 12 of the selected grinding grindstone 10 into a perfect circle. Subsequently, as shown in FIG. 4, a relief portion 14 is formed in the grindstone portion 12 of the grinding grindstone 10.
When grinding is performed by normal control with an oblique axis having an inclination angle θ = 45 ° using a cylindrical grinding wheel 10, the radius in the caliber direction of the strong curvature die 1 is X, and the depth of the strong curvature die 1 is When the dimension is Z, when Z ≧ X, it interferes with the edge of the strong curvature mold 1. If Z−X = ΔZ, the grinding wheel 10 interferes with the mold at the portion ΔZ. In forming the relief portion, the portion of the grinding wheel 10 that interferes is removed.
A cylindrical truer (molding grindstone) 30 is used for forming the escape portion 14. The inner diameter of the truer is the same as or slightly smaller than the design diameter of the strong curvature mold 1, and the grinding wheel 10 is operated under normal control by performing a design value calculated from the mold design shape. That is, the same operation as that for actually grinding the mold is performed. In this way, the portion of the grinding wheel portion 12 of the grinding wheel 10 that interferes with the edge of the strong curvature die is cut away, and the relief portion 14 can be formed. At this time, the shape of the escape portion 14 is a round shape.
By using this grinding wheel 10 for grinding of the high curvature die 1, the grinding can be performed without interference with the edge of the strong curvature die 1.

Next, the grinding wheel 10 is attached to a grinding machine, and the rigid curvature die 1 is finished by grinding (step S4).
Here, a configuration of a three-axis grinding machine will be described as an example of a grinding machine. As shown in FIG. 8, the grinding machine 40 includes an x-direction moving table 42 and a y-direction moving table 43 on a bed 41. A work spindle 44 is provided on the y-direction moving table 43 and is arranged so as to be driven to rotate about a rotation center axis 45 that is horizontal to the plane of the bed 41. A workpiece 46 is attached to the work spindle 44. On the x-direction moving table 42 is provided a rotating table 47 that is rotated around a rotation center axis 48 that is perpendicular to the plane of the bed 41, and a spindle holder 49 is erected on the rotating table 47. . The spindle holder 49 is attached with a lifting table 50 that can move vertically and vertically. A grinding spindle 51 is held at the tilt angle θ and tilts downward toward the workpiece 46 on the lifting table 50. Are arranged as follows. The grinding spindle 51 is attached with a tool 53 such as a grinding wheel that is driven to rotate about the rotation center axis 52.

The grinding spindle 51 is fixed to the elevating table 50 so as to be inclined at an inclination angle θ of 45 °, for example, and is moved up and down in the vertical vertical direction while maintaining the inclination angle θ as the elevating table 50 moves up and down. . Further, the grinding spindle 51 is set so that the tip end portion where the held tool 53 abuts on the workpiece 46 is aligned with the upper extension line of the rotation center shaft 48 of the rotary table 47.
On the other hand, the workpiece 46 is attached to the work spindle 44 in such an arrangement that the rotation center axis 45 coincides with the rotation center axis 45 of the work spindle 44.
Further, the tip of the tool 53 coincides with the upper extension line of the rotation center axis 48 of the rotary table 47 as described above, and also coincides with the horizontal plane passing through the rotation center axis 45 of the work spindle 44. The height position is adjusted by the vertical movement of.

  The grinding wheel 10 is attached to the grinding machine 40 as described above, and the rigid curvature die 1 is finished by grinding as shown in FIG. In this grinding process, a cylindrical grinding wheel 10 is arranged at an inclination angle θ = 45 ° with respect to the rotation center axis of the strong curvature die 1 and cross-cut grinding is performed by normal control. In cross-cut grinding, the rotational direction of the strong curvature die 1 and the peripheral speed vector of the grinding wheel 10 are orthogonal to each other, and a shape is created by a single processing point on the surface of the grinding wheel. And surface roughness PV of the concave surface 5 after a process is about 0.2-0.3 micrometer.

The relief portion 14 provided in the grindstone portion 12 of the grinding grindstone 10 has a shape and dimensions as shown in FIG.
When there is no escape portion 14, the grinding wheel 10 interferes with the ΔZ portion of the strong curvature mold 1. Here, the interference length L in the length direction of the grinding wheel 10 is L = 2ΔZsinθ, and the interference length W in the radial direction of the grinding wheel 10 is W = ΔZcosθ.
The additional amount in the length direction of the grinding wheel 10 is ΔX1, ΔX2, the additional amount in the radial direction of the grinding wheel 10 is ΔY1, the clearance length in the length direction of the grinding wheel 10 is ΔX, and the clearance length in the radial direction of the grinding wheel 10 Let ΔY be the thickness.
The radial relief length ΔY of the grinding wheel 10 is
ΔY = W + ΔY1 = ΔZcos θ + ΔY1 (1)
The relief length ΔX in the length direction of the grinding wheel 10 is
ΔX = L + ΔX1 + ΔX2 = 2ΔZsinθ + ΔX1 + ΔX2 (2)
It becomes.
Further, the additional amounts ΔX1, ΔX2 in the length direction of the grinding wheel 10 and the additional amount ΔY1 in the radial direction of the grinding wheel 10 are amounts of deflection in the respective directions during processing of the grinding wheel 10, and at least ΔY1 = α. , ΔX1 = ΔX2 = β, as long as it is ensured (the shake amount α = 0.1 to 2 μm and the shake amount β = 0.1 to 2 μm).
From this, the equations (1) and (2) are
ΔY = ΔZcos θ + α (3)
ΔX = 2ΔZsinθ + 2β (4)
It can be expressed as.
As described above, the relief portion 14 having a size satisfying at least the above equations (3) and (4) is formed on the grindstone portion 12 of the grinding wheel 10, so that the interference between the high-curvature mold 1 and the grinding wheel 10 can be prevented. Allows no grinding.

Next, according to the specification, the surface finished by grinding in step S4 is finish-polished (step S5). In this final polishing step, polishing is performed manually or by a machine in order to improve the surface roughness of the processed concave surface. In this mechanical polishing, for example, an ultrasonic-assisted micro polishing apparatus (Kyoshin Sangyo Co., Ltd., Nano-POLISHER) is used. The surface roughness PV of the processed surface in this finish polishing is about 0.1 μm.
Subsequently, surface treatment is performed on the strong curvature die for rust prevention of the strong curvature die (step S6).
The steps S5 and S6 are based on the design specifications of the strong curvature mold according to the optical lens specifications, and these steps may not be performed depending on the design specifications.

As described above, in the manufacturing method of the strong curvature mold 1 of the present embodiment, the opening diameter of the mold is small, and even in the processing of a concave mold having a strong curvature, the edge of the mold is used in the grinding process in the finishing process. The grinding wheel 10 does not interfere with each other, and the design shape can be processed. Further, according to this manufacturing method, by forming the relief portion 14 in the grinding wheel 10, it is possible to obtain the grinding wheel 10 that does not significantly impair the rigidity, and the degree of freedom of processing is improved and the accuracy is high. A method of manufacturing the curvature mold 1 can be provided.
Moreover, according to this manufacturing method, since a high-precision process is enabled by using a diamond abrasive grain for the grindstone part 12 of the grinding stone 10, and the bonding material of the diamond abrasive grains is a resin, It is hard to get scratches and can be finished to a good surface state without reducing the surface roughness.
Furthermore, the surface roughness of the concave surface of the high-curvature mold is improved by performing finish polishing after the finishing process by the grinding process, and the high-curvature mold 1 having high accuracy and good quality can be provided.
(Modification)

Next, a modification of the first embodiment will be described. In this modification, the manufacturing process is the same as in the first embodiment, but the shape of the relief portion in the grinding wheel is different, and this shape will be described. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.
FIGS. 6A and 6B are explanatory views for explaining the positional relationship between the mold and the grinding wheel in the first embodiment, FIG. 6A is a positional relationship diagram, and FIG. 6B is the details of the relief portion of the grinding wheel. It is an enlarged view shown.

  As shown in FIG. 6A, the grinding wheel 20 includes a cylindrical grindstone portion 12 and a shaft portion 11 that fixes the grindstone portion 12, and the grindstone portion 12 is provided with a relief portion 15. The diameter D of the grindstone 12 of the grinding wheel 20 is determined so that the relationship with the curvature radius R of the concave surface of the strong curvature die 1 is D / 2 <R, as in the first embodiment. . Further, the grindstone 12 is a resin-bonded grindstone (about # 3000) using diamond abrasive grains and using a polyimide resin or a phenol resin as a binding material.

The relief portion 15 of the grinding wheel 20 has a shape and dimensions as shown in FIG.
When there is no escape portion 15, the grinding wheel 20 interferes with the ΔZ portion of the strong curvature mold 1. In order to avoid this interference, the radial relief length ΔY of the grinding wheel 20 formed as the relief portion 15 and the longitudinal relief length ΔX of the grinding stone 20 are expressed by the above-described equations (3) and (4). It is the same.
The shape of the relief portion 15 is a stepped shape as shown in FIG. 6, and the relief portion 15 having a size satisfying at least the above formulas (3) and (4) is formed on the grinding stone portion 12 of the grinding stone 10. Thus, there is no interference between the strong curvature die 1 and the grinding wheel 10 and grinding can be performed.
Further, the relief portion 15 may be formed by using a forming grindstone having a width of ΔX and pressing it to a depth of ΔY in a direction orthogonal to the rotation axis of the grinding stone 20.
(Second Embodiment)

Next, a second embodiment of the method for manufacturing a strong curvature mold will be described.
FIG. 7 is a flowchart showing a manufacturing process of a strong curvature mold in the second embodiment. In the present embodiment, rough processing and finishing processing in processing of a curved surface of a strong curvature mold are performed by grinding.

  First, a mold is designed based on the specifications of the optical lens (step S11). Then, truing of the roughing grinding wheel and shaping of the relief portion are performed (step S12). The roughing grinding wheel is a resin-bonded grinding wheel (grain size of about # 400) having the same shape as the grinding wheel described in FIG. 5 or 6 and having a cylindrical grinding wheel portion and using diamond abrasive grains. is there. The truing of the roughing grinding wheel and the shaping of the relief portion are the same as the method shown in the first embodiment.

  Next, rough processing of the concave surface of the mold is performed by the grinding machine described with reference to FIG. 8 using the grinding wheel formed in step S12 (step S13). In this grinding process, the grinding wheel is disposed at an inclination angle θ = 45 ° with respect to the rotation center axis of the strong curvature mold, and cross-cut grinding by normal control is performed. At this time, since the relief portion is formed on the grinding wheel, grinding can be performed without interfering with the edge of the strong curvature die. Further, although the concave surface has a rough surface, the processing is performed up to the shape shown in FIG.

  Next, in order to perform grinding on the concave surface formed in step S13, truing of the grinding wheel for finishing and shaping of the relief portion are performed (step S14). The grindstone portion of the finishing grindstone is a resin-bonded grindstone (grain size # 3000 or so) using diamond abrasive grains. Further, the truing of the finishing grindstone and the forming of the relief portion are the same as the method shown in the first embodiment.

  Next, the above-mentioned finishing grinding wheel is attached to the grinding machine, and the rigid curvature die is finished by grinding (step S15). In this grinding process, the grinding wheel is disposed at an inclination angle θ = 45 ° with respect to the rotation center axis of the strong curvature mold, and cross-cut grinding by normal control is performed. At this time, since the relief portion is formed on the grinding wheel, grinding can be performed without interfering with the edge of the strong curvature die. The surface roughness PV of the processed surface is about 0.2 to 0.3 μm.

Next, according to the specification, the surface finished by grinding in step S15 is finish-polished (step S16). In this final polishing step, polishing is performed manually or by a machine in order to improve the surface roughness of the processed concave surface. In this mechanical polishing, for example, an ultrasonic-assisted micro polishing apparatus (Kyoshin Sangyo Co., Ltd., Nano-POLISHER) is used. The surface roughness PV of the processed surface in this finish polishing is about 0.1 μm.
Subsequently, surface treatment is performed on the strong curvature die for rust prevention of the strong curvature die (step S17).
The steps S16 and S17 are based on the design specifications of the strong curvature mold according to the optical lens specifications, and these steps may not be performed depending on the design specifications.

  As described above, according to the method of manufacturing a strong curvature mold of the present embodiment, grinding can be performed in the roughing and finishing of the concave surface, and the roughing and finishing can be performed using the same apparatus. Can be manufactured. Thus, in addition to the effects of the first embodiment, the versatility of the manufacturing apparatus can be improved, and an efficient strong curvature mold can be manufactured.

  In this embodiment, cross-cut grinding is described as an example of the grinding method. However, in parallel grinding in which the rotational direction of the strong curvature mold and the peripheral speed vector of the grinding wheel are parallel and the machining point moves on the surface of the grinding wheel. Can also be implemented.

It is a block diagram which shows schematic shape of the strong curvature metal mold | die concerning 1st Embodiment, (a) is a schematic plan view, (b) is a schematic sectional drawing in alignment with the AA disconnection of (a). The flowchart which shows the manufacturing process of the strong curvature metal mold | die in 1st Embodiment. Explanatory drawing which shows the grinding wheel and metal mold | die curvature radius in 1st Embodiment. Explanatory drawing explaining shaping | molding of the grinding stone in 1st Embodiment. It is explanatory drawing explaining the positional relationship of the metal mold | die and grinding wheel in 1st Embodiment, (a) is a positional relationship figure, (b) is an enlarged view which shows the detail of the escape part of a grinding wheel. The modification of the grinding wheel concerning a 1st embodiment is shown, (a) is the position related figure of a metallic mold and a grinding wheel, and (b) is an enlarged view showing the details of the escape part of a grinding wheel. The flowchart which shows the manufacturing process of the strong curvature metal mold | die in 2nd Embodiment. It is a block diagram which shows the structure of a grinding machine, (a) is a schematic side view, (b) is a schematic plan view. Explanatory drawing explaining the strong curvature of an optical lens. Explanatory drawing explaining the positional relationship of the conventional metal mold | die and a grinding wheel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Strong curvature metal mold | die, 5 ... Concave surface, 10 ... Grinding wheel, 11 ... Shaft part, 12 ... Grinding wheel part, 14, 15 ... Relief part, 20 ... Grinding wheel, 21 ... Shaft part, 22 ... Grinding wheel part, 24 ... relief portion, 30 ... truer, 35 ... optical lens, 40 ... grinding machine, theta ... inclination angle, theta _S ... measurement surface tilt angle, X ... intense curvature die diameter direction of the radius, the Z ... strong curvature mold Depth dimension, ΔZ: Interference length in the depth direction of the strong curvature mold, ΔY: Relief dimension in the radial direction of the grindstone, ΔX: Relief dimension in the length direction of the grindstone, W: Interference length in the radial direction of the grindstone, L ... Interference length in the length direction of the grinding wheel, α ... Amount of deflection in the radial direction of the grinding wheel, β ... Amount of deflection in the length direction of the grinding wheel, D ... Diameter of the grinding wheel portion in the grinding wheel, R ... Radius of curvature of the strong curvature mold .

Claims (4)

A method for manufacturing a mold,
Roughing the concave surface;
A step of finishing the roughened roughened surface by grinding using a cylindrical grinding wheel,
In the step of finishing,
When the radius of curvature of the mold is R and the diameter of the grinding wheel is D, the relationship is D / 2 <R.
The inclination angle between the rotation center axis of the mold and the grinding wheel is θ, the interference length with the grinding wheel in the depth direction of the mold is ΔZ, the runout amount in the radial direction of the grinding wheel is α, the grinding When the amount of runout in the length direction of the grindstone is β, the dimension of the relief part in the radial direction of the grinding wheel is ΔY, and the dimension of the relief part in the length direction of the grinding wheel is ΔX,
A method of manufacturing a mold, comprising using the grinding wheel in which relief portions of ΔY = ΔZcos θ + α and ΔX = 2ΔZsinθ + 2β are formed at least in a portion that interferes with the edge of the mold during grinding. In the manufacturing method of the metal mold according to claim 1,
A method for producing a mold, wherein the grinding wheel is a resin-bonded grinding wheel using diamond abrasive grains. In the manufacturing method of the metal mold according to claim 1 or 2,
The roughing step is grinding using the grinding wheel,
When the radius of curvature of the mold is R and the diameter of the grinding wheel is D, the relationship is D / 2 <R.
The inclination angle between the rotation center axis of the mold and the grinding wheel is θ, the interference length with the grinding wheel in the depth direction of the mold is ΔZ, the runout amount in the radial direction of the grinding wheel is α, the grinding When the amount of runout in the length direction of the grindstone is β, the dimension of the relief part in the radial direction of the grinding wheel is ΔY, and the dimension of the relief part in the length direction of the grinding wheel is ΔX,
A method of manufacturing a mold, comprising using the grinding wheel in which relief portions of ΔY = ΔZcos θ + α and ΔX = 2ΔZsinθ + 2β are formed at least in a portion that interferes with the edge of the mold during grinding. In the manufacturing method of the metallic mold according to any one of claims 1 to 3,
A method of manufacturing a mold, comprising a step of performing a final polishing after the step of finishing.

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