JP4851713B2 - Rotating tools for shaping the shape of mineral materials such as sapphire, especially shaping the optical surface of a watch crystal - Google Patents

Description

      The present invention relates to a method for machining mineral materials, in particular hard materials such as sapphire, corundum, spinel, etc., and more particularly to a rotating tool for machining hard materials suitable for shaping the optical surface of a watch glass. .

      A method for forming an optical surface in the form of a convex lens in the thickness direction on the surface of a transparent mineral material is known from US Pat. Said patent document is incorporated herein in its entirety. The method disclosed herein includes a step of setting a plate to rotate about a first axis orthogonal to a region forming a lens, and a region required by an abrasive member rotating about a second axis. And processing steps. The second axis is different from the first axis and intersects the first axis at the required center of curvature of the lens. The tool and the plate are oscillated at a distance away from the region by a distance equal to the required radius of curvature of the lens about a third axis orthogonal to the plane including the first and second rotation axes. Is preferred. This oscillating operation allows the sharpening of the abrasive member.

European Patent No. 0123891

      According to the method described above, the rotary tool used to shape the lens is a cylindrical polishing member (or a shape with a tip cut off), and the active end is mounted with an abrasive material formed from diamond powder. Yes. The cost of this tool is relatively high because the material to be machined (usually in the case of mineral materials such as sapphire) and the abrasive material (usually diamond powder or sapphire) incorporated into the tool head This is because the complexity of the manufacturing process of such a tool must be considered. The life of such tools is relatively short and must be replaced periodically. Therefore, the above-mentioned points are heavily applied to the manufacturing cost of the object to be molded.

      A simpler and more efficient solution must be found. The object of the present invention is to provide such a solution, i.e. a hard material, particularly suitable for shaping lenses or a hard material (e.g., forming the optical surface of a hard material watch glass). To provide a rotating tool for machining sapphire, corundum, spinel, etc.). Another object of the present invention is to provide a solution that is low in cost and simple to use.

      The invention relates to a rotary tool for shaping mineral materials, in particular hard mineral materials, the features of which are set forth in claim 1.

      The present invention is a method for shaping a deformed optical surface of a transparent hard material (especially sapphire, corundum, spinel, etc.), the characteristics of which are described in claim 8.

      The invention further relates to an apparatus for machining mineral materials, in particular hard mineral materials, which is an apparatus incorporating such a tool. Its characteristics are described in claim 12.

      The tool of the present invention has a body that results in a head that includes an active surface that contacts a region of mineral material that is to form the required shape. The tool head has at least one first slot, preferably several slots, which are perforated towards the active surface, form an opening therein, and have the shape in which abrasive particles are required. Sent to the area to be formed and stays on its active surface. Along one of the openings formed on the active surface, one or more cutting edges are formed to help machine the required shape.

      It should be understood that the rotating tool of the present invention does not actually constitute a polishing tool for mineral materials. The polishing ability of the tool is formed by both the tool (especially the slots arranged on the tool head and the corresponding opening on the active surface of the head) and the abrasive particles transported onto the machining area. With each opening on the active surface formed by the corresponding slot, abrasive particles stay in and accumulate in the raised portion with a powerful polishing force on the active surface of the tool head that functions as a cutting edge. Form. Thus, the rotating tool itself constitutes a matrix that fixes or sets the abrasive particles in an appropriate shape that allows the mineral material to be shaped to be polished.

      The tool head does not polish the mineral material to be polished, it performs an intermediate function between hard and soft to maintain and maintain the shape of the head, and abrasive particles are implanted in it. Formed from material. This material is, for example, a metal selected from the group consisting of copper Cu, zinc Zn, tin Sn, and iron Fe, or an alloy containing at least one of these metals.

      The arrangement of the slot openings on the active surface of the tool head follows a suitable shape arrangement. The simplest is an array of one or more slots having a substantially linear shape. Slots that form diametrical or parallel openings in the active area of the tool head can also be arranged in any suitable manner on the tool head.

      To obtain even better results in terms of surface quality, the arrangement of each slot covers the rotating surface where the cutting edge formed by the slot is defined only by the outer diameter when the tool is rotated. That is, to cover a rigid surface without a recess in the center.

      The advantage of the present invention is that the rotary tool is very simple to manufacture and inexpensive. The reason is especially because of the type of material used to manufacture the tool and because no abrasive material is incorporated into the tool head. This abrasive material is conveyed directly to the machining area in the form of abrasive particles conveyed by a fluid or liquid. In this regard, a preferred variation is to arrange at least one slot such that the slot acts as a channel for carrying abrasive particles.

      According to the present invention, the cost for forming the necessary shape for the mineral material to be polished is greatly reduced. This advantage is particularly critical for shaping mineral materials (eg sapphire, corundum, spinel, etc.), which is particularly beneficial in the watch industry, such as producing watch glass. Thus, the present invention is suitable for forming optical or refractive optical surfaces (especially deformed optical surfaces such as magnifying lenses) in a transparent mineral material (eg sapphire) having a very high hardness.

      The machining apparatus shown in FIG. 1 is similar to the apparatus disclosed in the above-mentioned Patent Document 1. The machining apparatus of the present invention has a frame support member 10 on which a column 12 and a headstock 14 are mounted. The column 12 has a spindle 16, and at one end thereof is a rotary tool 20 having the same rotation axis 42 as the spindle 16. The rotary tool 20 has a cylindrical body, which becomes a head 20a that contacts a region of mineral material to be machined. The pulley 18 is mounted on the spindle 16 and rotates the spindle 16 about a rotation shaft 42 by motor means (not shown). The column 12 further has slide surfaces 22, 24, and 26 to drive the rotary tool 20 along three orthogonal axes as in the prior art. Specifically, the slide surface 22 moves the tool in the vertical direction along its rotation axis via a small screw 23, while the slide surfaces 24 and 26 move the rotary tool 20 via a small screw 25 and 27, respectively. Move horizontally along two orthogonal directions.

      The headstock 14 has a spindle 28 whose end 28 a is in the vicinity of the column 12. The column 12 moves downward with respect to the rotation shaft 44 of the spindle 28 by an elbow. A table 30 is mounted on the shaft 32. The shaft 32 is orthogonal to the rotation axis 44 of the spindle 28 and is supported by the end portion 28a. The shaft 32 has a pulley 34, and the pulley 34 is rotated about a rotation shaft 40 by a motor (not shown). The support 36 is fixed to the table 30 and further fixes a mineral material plate 38. The plate 38 is, for example, a hard transparent mineral material (e.g., sapphire, corundum, spinel (e.g., a surface forming a watch glass)) to which a lens or other deformed optical surface fits.

      The rotary tool 20 and the support base 36 rotate in opposite directions. The thickness of the support base 36 is such that the distance between the axis of the spindle 28 and the tip of the spherical surface to be formed (located on the rotational axis 40 of the shaft 32) is the radius R of the curved surface of the spherical surface. The thickness is such that Finally, the spindle 28 is engaged with a driving means (not shown) to give a small amplitude vibration, or at least adjust the inclination relative to the horizontal plane.

      The machining apparatus has several alternative configurations in the way the rotary tool 20 and plate 38 are driven and arranged. Although various operation modes of the machining apparatus are conceivable, these various operation modes commonly include a mode in which the rotary tool 20 is rotated around the rotation axis 42. This rotation can be achieved, if necessary, by rotating or vibrating the plate 38 around the rotation axis 40 and / or vibrating the plate 38 about the spindle 28 axis. (This vibration motion can be applied to the rotary tool 20 in another way if the column 12 is adapted to the appropriate means.) The motion and vibration of driving the rotary tool 20 and the plate 38 simultaneously and the plate Regarding the operation to be added to 38, refer to the method disclosed in the above-mentioned Patent Document 1.

In addition to the drive means and positioning means described above, the machining apparatus of the present invention includes means for transporting abrasive particles to the region of mineral material where the required shape is to be formed. This transport means is shown in FIG. 1 and includes a tank 50 containing a carrier fluid for abrasive particles (eg, diamond powder suspended in oil) and a supply path 52 for transporting this fluid to the processing area. The amount of abrasive particles transported to the processing area is adjusted by means not shown. As will be apparent from the following description, according to the present invention, it is possible to form the necessary shape on the surface of the mineral material by transporting the abrasive particles to the processing region and the rotating tool.

      2-4 shows a perspective view, a top view, and a cross-sectional view of the end of the rotary tool 20 constituting the embodiment of the present invention. As shown in FIGS. 2-4, the body of the rotary tool 20 becomes the head 20a and has an active surface 200 that contacts the region of mineral material where the required shape is to be formed. In this embodiment, the active surface 200 of the tool has the shape of a concave spherical disc, the radius of which corresponds to the radius of curvature R of the shape to be formed (in this embodiment a convex spherical optical surface). In this case, when the tool is moved by the machining apparatus shown in FIG. 1, the rotation axis 40 of the shaft 32, the rotation axis 42 of the spindle 16, and the rotation axis 44 of the spindle 28 are formed of the mineral material plate 38. It means to intersect at point C corresponding to the center of curvature of the convex spherical surface to be. This is detailed in FIG.

      It should be noted that the active surface 200 of the rotary tool 20 has a shape different from a strict spherical shape. Thus, the active surface 200 of the head 20a takes the shape of a part of the conic curve rotation surface (toroid part). This is similar to the shape of the polishing member shown in the second modification of Patent Document 1 (in particular, this shape requires specific adjustment of the polishing apparatus). In general, the active surface of the tool can take any suitable shape. In any case, the shape formed in the mineral material depends not only on the shape of the active surface of the tool, but also on some movement applied to the tool and / or the plate. The shape of the active surface of the tool head does not necessarily correspond (fit) with the surface shape to be formed.

      In accordance with the present invention, the tool head 20a has at least a first slot opening above the active surface 200 and forms an opening therein. In the embodiment shown in FIGS. 2-4, the tool head 20a now has a pair of diametric slots 210, 220, ie two linear slots arranged in a diameter plane through the rotational axis 42 of the rotary tool 20. Have. These diametric slots 210, 220 extend to the end of the head 20a and are substantially orthogonal, thereby forming a pair of orthogonal slots 210a, 220a on the active surface 200 of the tool. The active surface 200 of the rotary tool 20 is divided into four individual parts, which in this embodiment have approximately equal surface areas.

      The arrangement and shape of the diametric slots 210, 220 shown in this embodiment are not limited to this. Thus, one slot or more than two slots can be arranged on the head. Furthermore, these slots may be parallel without intersecting. Finally, the slot and its corresponding opening on the active surface of the tool may not be straight. This straight line shape is easy to realize.

      For example, the tool head can fit in only one slot, but this slot does not necessarily have to be formed across the entire width of the active surface. The preferred shape of the slot is such that when the tool is rotated, the cutting edge formed by the opening corresponding to the slot covers a rotating surface formed solely from the external shape, a rigid surface without a central recess. is there. This configuration is preferable from the viewpoint of the surface quality of the shape to be formed. The diametric slot structure shown in FIGS. 2-4 answers this requirement.

      The method of extending the slot into the tool head is not critical to the present invention. In practice, the important point is that the slot is open on the active surface of the tool head. In practice, the important point is that abrasive particles are added to the surface through the active surface of the tool and during machining to form the mineral material.

      As previously mentioned, each opening in the active surface formed by the corresponding slot causes abrasive particles to stay and accumulate therein, providing a large polishing force with the function of a cutting edge on the active surface of the tool head. Constructs a raised portion. Thus, the rotating tool forms a matrix for fixing and setting the abrasive particles with an appropriate structure, and thereby the mineral material to be molded is polished.

      The rotary tool 20 is preferably formed from a material that is not polished relative to the mineral material involved. It is preferably formed from a material having both hardness and softness for maintaining and maintaining the shape of the head, whereby the shape of the head is maintained and the abrasive particles are injected therein.

      This material is a metal or metal alloy, and includes at least a metal selected from the group consisting of copper Cu, zinc Z, tin Sn, and iron Fe.

      As a variation of the present invention, the tool slot configuration is configured to act as a channel through which abrasive particles are transported to the machining area. This transport channel is a formed slot and is integral with the abrasive particle transport means to replace or complete the supply channel 52 of FIG.

      An embodiment of the present invention for machining a convex lens (ie, a convex spherical surface having a circular shape) will be described with reference to FIG.

      The tool shown in FIGS. 2-4 can easily form a convex lens in the thickness direction of the surface of the transparent mineral material. To do this, the plate 38 is tilted by a predetermined angle α by means of the spindle 28 of FIG. This α corresponds to an angle formed by the rotation axis 40 of the plate 38 and the rotation axis 42 of the rotary tool 20 (that is, an axis orthogonal to the region where the lens is formed and passing through the center of the region). The rotation axes 40 and 42 both pass through the curved surface C of the spherical surface indicated by the spherical surface 380 in FIG. Thereafter, the rotary tool 20 and the plate 38 are set to rotate (by the spindle 16 and the shaft 32 and associated driving means) about the respective rotation axes 42 and 40. The active surface 200 of the rotary tool 20 comes into contact with the plate 38. In FIG. 5, abrasive particles 500 represent a mixture that is transported onto a machining area that includes abrasive particles.

      As shown in FIG. 5, by rotating the active surface 200 and the plate 38 about their respective rotational axes and adjusting the angle α between these rotational axes, the active surface 200 of the tool can have a radius of curvature R and A part of a convex spherical surface having a circular shape (in other words, a disk forming a part of the convex spherical shape) is formed. Unless a vibrating motion is applied to the tool or plate, the minimum value of the tool head diameter d (FIG. 3) is greater than half the diameter D of the lens to be formed. More specifically, the rotational tool 20 has a diameter d at least equal to half the lens diameter D required by cosine α in this embodiment. In practice, the angle α is 20 ° or less, preferably 10 ° or less.

As disclosed in the above-mentioned Patent Document 1, instead of inclining and fixing the surface with respect to the tool by a predetermined angle, an axis perpendicular to the rotation axes 42 and 40 and passing through the center of curvature C of the lens to be formed Is vibrated around the center of the plate 38 (ie, the vibrating motion around the rotation axis 44 of the spindle 28 in FIG. 1) is applied to the plate 38 (or tool). In such a case, the maximum angle of inclination of the plate 38 relative to the rotational tool 20 is alpha _max is expressed by the following equation. This is effective for small amplitudes (small angle α).
(1) tan α _max = [2R (D−d)] / [4R ² + Dd]
The above = has almost the same meaning. The above relational expression (1) is effective for the above-described polishing operation with respect to a constant inclination.

      The tool shown in FIG. 2-4 can form a convex spherical surface that does not necessarily have a circular sphere.

      Thus, referring to FIG. 5, this includes making the plate 38 repeat the oscillating motion about the rotational axis 40 instead of the rotational motion. By limiting the maximum amplitude value of the oscillating motion about the axis of rotation 40, for example by exposing the plate to an oscillating angular movement of about 180 °, a portion of the spherical disk is approximately C-shaped in the plane of the plate. It can be configured to have a shape.

      Similarly, without rotating the plate 38 about the rotation axis 40, the plate 38 is oscillated around an axis perpendicular to the rotation axis 42 of the tool and passing through the center of curvature C of the spherical surface (for example, the plate 38 It is also included in the present invention to be exposed to (vibrating motion about the rotation axis 44). An elongated (ie rectangular) convex spherical surface is thus obtained.

      For the latter embodiment, the rotary tool 20 is tilted in a plane that includes the axis of rotation 44 on which the plate 38 vibrates, so that the axis of rotation 42 of the rotary tool 20 intersects at the center of curvature C of the spherical surface to be formed. This is also included in the present invention. This means that the rotary tool 20 of FIG. 1 is inclined on the plane of FIG. 1, thus requiring arrangement means (not shown) for such an angle adjustment. The result is a convex spherical surface that is also an elongated shape, which is inclined in the width direction with respect to the intermediate surface of the plate 38 instead of a perfectly symmetrical surface as in the previous embodiment.

      In these three embodiments, the rotational motion about the rotational axis 42 of the rotary tool 20 is performed by repeated relative (ie, oscillating) motion between the rotary tool 20 and the plate 38, thereby preventing non-rotation. A spherical optical surface having a circular shape can be formed. More complex shapes can cause multiple oscillating motions of various axes through the center of curvature of a spherical surface or, if a toroid surface is required, through the center of curvature of its non-concurrent surface. Obtained by synchronizing. Those skilled in the art can refer to the embodiments of the present invention and make various modifications without departing from the scope of the present invention.

      In particular, the active surface of the tool head can take a shape other than spherical, provided that the tool is not subject to movement relative to the surface of the mineral material to be machined. By simply rotating the tool (or rotating the surface of the mineral material about the same axis as the rotation axis of the tool), it is possible to give the active surface of the tool a non-spherical shape of rotation, and to the mineral material It is also possible to form corresponding shapes. The particularly simple spherical shape of the active surface of the tool head is a relatively simple solution as disclosed herein, and various shapes of recesses can be formed and used in the material.

      Arranging a slot or slots on the active surface of the tool head is done according to a suitable geometry, the simplest of these being one or more straight slots .

      The above description relates to one embodiment of the present invention, and those skilled in the art can consider various modifications of the present invention, all of which are included in the technical scope of the present invention. The The numbers in parentheses described after the constituent elements of the claims correspond to the part numbers in the drawings, are attached for easy understanding of the invention, and are used for limiting the invention. Must not. In addition, the part numbers in the description and the claims are not necessarily the same even with the same number. This is for the reason described above.

The figure showing the machining apparatus which forms the optical deformation | transformation surface (for example, spherical convex lens) in the hard transparent material of the timepiece glass which mounts the rotation tool by this invention. 1 is a perspective view of an end, head, or rotating tool according to one embodiment of the present invention. FIG. 3 is a top view of the active surface of the head of the rotary tool of FIG. 2. FIG. 4 is a cross-sectional view of the rotating tool taken along line AA in FIG. 3. The figure showing the state in which the rotary tool by this invention machines a spherical convex lens with the circular periphery of the surface of a transparent mineral material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Frame support member 12 Column 14 Spindle 16 Spindle 18 Pulley 20 Rotary tool 20a Head 22 Slide surface 23 Small screw 24 Slide surface 25 Small screw 26 Slide surface 27 Small screw 28 Spindle 28a End part 30 Table 32 Shaft 34 Pulley 36 Support stand 38 Plate 40 Rotating shaft 42 Rotating shaft 44 Rotating shaft 50 Tank 52 Supply path 200 Active surface 210 Diameter slot 210a Vertical slot 220 Diameter slot 220a Vertical slot 500 Abrasive particles

Claims (7)

In a method of forming an optical surface (380) on a transparent mineral material, in particular a sapphire, corundum, spinel plate (38),
The rotary tool (20) has a polishing body whose end constitutes a head (20a),
Said head (20a) has an active surface (200) in contact with a plate (38) of mineral material which is a mineral material to be polished;
The head (20a) has slots (210, 220) that form openings (210a, 220a) in the active surface (200);
The head (20a) is formed of a material that does not polish the polished mineral material,
(A) rotating the tool (20) about the first rotation axis (42);
(B) contacting the active surface (200) of the head of the tool with the plate (38) of the mineral material to be polished;
(C) supplying abrasive particles (500) through the openings (210a, 220a);
As a result, the abrasive particles (500) stay in the openings (210a, 220a) of the active surface (200) to form a raised polishing edge along the openings (210a, 220a) on the active surface. ,
(D) A method of forming an optical surface on a plate (38) of mineral material comprising the step of relatively moving the tool (20) and the plate (38) of mineral material to be polished. In a method of forming an optical surface (380) on a transparent mineral material, in particular a sapphire, corundum, spinel plate (38),
The rotary tool (20) has a polishing body whose end constitutes a head (20a),
Said head (20a) has an active surface (200) in contact with a plate (38) of mineral material which is a mineral material to be polished;
The head (20a) has slots (210, 220) that form openings (210a, 220a) in the active surface (200);
The head (20a) is formed of a metal selected from the group consisting of Cu, Zn, Sn, and Fe, or a metal alloy thereof, which is a material that does not polish the mineral material to be polished.
(A) rotating the tool (20) about the first rotation axis (42);
(B) contacting the active surface (200) of the head of the tool with the plate (38) of the mineral material to be polished;
(C) supplying abrasive particles (500) through the openings (210a, 220a);
As a result, the abrasive particles (500) stay in the openings (210a, 220a) of the active surface (200) to form a raised polishing edge along the openings (210a, 220a) on the active surface. ,
(D) A method of forming an optical surface on a plate (38) of mineral material comprising the step of relatively moving the tool (20) and the plate (38) of mineral material to be polished. The active surface (200) has the shape of a concave spherical surface having a radius of curvature (R) corresponding to the radius of curvature to which an optical surface is to be formed;
(E) rotating the plate (38) about a second rotation axis (40) perpendicular to the plate (38) and passing through the center of the plate (38);
3. A method according to claim 1 or 2, characterized in that the first and second axes of rotation (42, 40) pass through a center point (c) of curvature where a convex spherical surface is formed. The active surface (200) has the shape of a concave spherical surface having a radius of curvature (R) corresponding to the radius of curvature to which an optical surface is to be formed;
3. The method of claim 1 or 2, further comprising the step of repeatedly performing relative movement of the plate (38) and the tool (20) to form a non-circular spherical optical surface. the method of. The step (D) comprises the tool (20) or plate (centered around an axis (40; 44) intersecting the first axis at the center of curvature (c) of the convex spherical surface to be formed. 38. The method of claim 4, wherein the vibrational motion is 38). The tool head (20a) has at least a pair of slots (210, 220) forming diametrically or parallel openings (210a, 220a) on the active surface (200). The method according to claim 1 or 2. The method of claim 6, wherein at least one of the slots (210, 220) serves as a channel for transporting the abrasive particles (500) toward the plate (38).

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