Method and Device for Finely Machining Axicons, Fine Machining Device Suitable for this Purpose,and Use Thereof

Abstract

In a method for fine-processing of an axicon (L) having a concave or convex cone surface (KF) with a cone axis (KA) and a cone angle (), with use of geometrically indeterminate cutting edges in the form of grain in combination with a liquid at a processing region (BB) of a tool (W2), which is constructed for linear engagement (LE) with the cone surface and has a front end (EB) with respect to the cone axis, material removal is produced at the cone surface by a relative cutting speed which results from a rotational movement of the axicon about the cone axis and a relative oscillating linear movement (oscillation axis R) of the tool, in which the processing region is disposed in linear engagement with the cone surface and its front end moves back and forth in a direction radial with respect to the cone axis.

Claims

1. A method for fine-processing of an axicon (L), which has at least one concave or convex cone surface (KF) with a cone axis (KA) and a cone angle (), by use of a tool (W1, W2) which has a processing region (BB) for linear engagement (LE) with the cone surface (KF) to be processed, the processing region having a front end (EB) with respect to the cone axis (KA), with use of geometrically indeterminate cutting edges in the form of bound or loose grain in combination with a liquid at the processing region (BB) of the tool (W1, W2), wherein material removal is produced by use of the tool (W1, W2) at the cone surface (KF) of the axicon (L) by a relative cutting speed resulting solely from a rotational movement (D) of the axicon (L) about the cone axis (KA) and a relative oscillating linear movement (oscillation axis R) of the tool (W1, W2) that in this case is disposed in linear engagement (LE) with the cone surface (KF) to be processed, in which the front end (EB) of the processing region (BB) as seen in a plan view moves back and forth in a direction radial with respect to the cone axis (KA).

2. A method for fine-processing of an axicon (L) according to claim 1, wherein initially a relative aligning and adjusting movement is produced between the axicon (L) and the tool (W1, W2) in accordance with the cone angle (), as a consequence of which the processing region (BB) of the tool (W1, W2) comes into the linear engagement (LE) with the cone surface (KF) of the axicon (L), wherein the front end (EB) of the processing region (BB) faces the cone axis (KA), whereupon the relative oscillating linear movement (oscillation axis R) is produced between the axicon (L), which is driven to rotate about the cone axis (KA) (workpiece axis D of rotation), and the tool (W1, W2) as an advance movement in which the front end (EB) of the processing region (BB) during a revolution of the axicon (L) about the cone axis (KA) moves as seen in plan view multiple times over the cone surface (KF) in radial direction with respect to the cone axis (KA) from an outer edge region (RB) of the cone surface (KF) to at least the proximity of the cone axis (KA) and back again.

3. A method for fine-processing of an axicon (L) according to claim 1, wherein during the fine-processing of the cone surface (KF) a rotational speed of the axicon (L) about the cone axis (KA) and a frequency of the relative oscillating linear movement (oscillation axis R) of the tool (W1, W2) over the cone surface (KF) are so matched to one another that the number of reciprocating movements of the tool (W1, W2) per revolution of the axicon (L) is an uneven number.

4. A method for fine-processing of an axicon (L) according to claim 3, wherein during the fine-processing of the cone surface (KF) the number of reciprocating movements of the tool (W1, W2) per revolution of the axicon (L) about the cone axis (KA) is greater than or equal to three and smaller than or equal to seven.

5. A device (10) for fine-processing of an axicon (L), which has at least one concave or convex cone surface (KF) with a cone axis (KA) and a cone angle (), by a tool (W1, W2) having a processing region (BB) for linear engagement (LE) with the cone surface (KF) to be processed, wherein the device (10) has a base (22), which is adapted to be flange-mounted on a tool spindle (14) of a fine-processing machine (12) and on which is mounted a guide arrangement (24) guiding a tool carriage (26), which is drivable for oscillation along an oscillation axis (R) and which carries the tool (W1, W2) for fine-processing of the axicon (L), to be longitudinally movable.

6. A device (10) according to claim 5, wherein the guide arrangement (24) comprises a guide frame (48) on which guide rails (52) for the tool carriage (26) are mounted on mutually opposite sides.

7. A device (10) according to claim 6, wherein the guide rails (52) are made of a slide bearing material and have a respective V-shaped groove (54) on each of mutually facing sides, wherein the tool carriage (26) on each of mutually remote sides has a respective wedge-shaped guide section (56) and wherein the wedge-shaped guide sections (56) of the tool carriage (26) are received in the V-shaped grooves (54) of the guide rails (52) to be capable of sliding.

8. A device (10) according to claim 5, wherein provided for the oscillatory drive of the tool carriage (26) is a transmission mechanism (58) adapted to convert a rotational movement produced by the tool spindle (14) of the fine-processing machine (12) into a reciprocating linear movement of the tool carriage (26) along the oscillation axis (R).

9. A device (10) according to claim 8, wherein the transmission mechanism (58) comprises a rotary disc (60), which is drivably connectable with the tool spindle (14) of the fine-processing machine (12) and is rotatable about an axis (C) of rotation and on which a guide pin (64) is mounted to be radially offset with respect to the axis (C) of rotation, the pin engaging in a slot (66, 76) which is formed to extend in the tool carriage (26) transversely to the oscillation axis (R) so that the tool carriage (26) is drivable to oscillate along the oscillation axis (R) with a predetermined stroke (H1, H2, H3).

10. A device (10) according to claim 9, wherein the rotary disc (60) is provided with a plurality of securing bores (68, 70, 72) for the guide pin (64), the bores having a different radial spacing (r1, r2, r3) from the axis (C) of rotation so that the stroke (H1, H2, H3) of the tool carriage (26) is settable.

11. A device (10) according to claim 9, wherein the tool carriage (26) has at least two mutually parallelly extending slots (66, 76) for selectable engagement of the guide pin (64), by way of which an axial relative position of the tool carriage (26) with respect to the axis (C) of rotation is settable.

12. A device (10) according to claim 5, wherein a connecting part (80) with a further guide arrangement (88) is mounted on the tool carriage (26) and serves for guiding the tool (W1, W2) to be movable in a direction transverse to the oscillation axis (R) of the tool carriage (26) and wherein the tool (W1, W2) is loaded in the direction transverse to the oscillation axis (R) of the tool carriage (26) by a force urging the tool (W1, W2) away from the connecting part (80).

13. A device (10) according to claim 12, wherein the force is supplied by at least two mutually repelling magnets (108) arranged between the connecting part (80) and the tool (W1, W2).

14. A device (10) according to claim 12, wherein the further guide arrangement (88) comprises at least one guide cylinder (90).

15. A device (10) according to claim 12, wherein the connecting part (80) is secured to the tool carriage (26) to be variable in its axial position along the oscillation axis (R).

16. A device (10) according to claim 12, wherein the tool (W1, W2) is mounted on the further guide arrangement (88) to be variable in its axial position along the oscillation axis (R).

17. A device (10) according to claim 5, wherein the tool (W1) as seen in plan view has substantially the form of an isosceles triangle, with a processing region (BB) which has a front end (EB) at a tip of the triangle and which on each of mutually opposite longitudinal sides of the triangle allows for respective linear engagement (LE) with the cone surface (KF) to be processed of the axicon (L).

18. A device (10) according to claim 5, wherein the tool (W2) is substantially strip-shaped with a processing region (BB) which has a front end (EB) at a transverse side of the tool (W2) and which along a longitudinal side of the tool (W2) allows for linear engagement (LE) with the cone surface (KF) to be processed of the axicon (L).

19. A fine-processing machine (12), comprising a tool spindle (14) with a tool axis (C) of rotation and a workpiece spindle (16) with a workpiece axis (D) of rotation, which project into a work space (18) bounded by a machine bed (20) and which are movable relative to one another (Y axis, Z axis) at least in a notional plane (Y-Z) spanned by the tool axis (C) of rotation and the workpiece axis (D) of rotation as well as pivotable relative to one another with respect to a pivot axis (A axis) extending perpendicularly to the plane (Y-Z), wherein a device (10) for fine-processing of an axicon (L) according to claim 5 is mounted on an end of the tool spindle (14) facing the workpiece spindle (16).

20. A fine-processing machine (12) according to claim 19, wherein the machine bed (20) has two side walls (28) between which the work space (18) is formed and which mount a portal (30), which is movable in a longitudinal direction (Y axis) and at which the tool spindle (14) is guided to be movable at least in a direction (Z axis) perpendicular to the longitudinal direction (Y axis), and wherein a yoke (36) is provided in the work space (18), which carries the workpiece spindle (16) and is mounted on the side walls (28) to be rotatable about the axis (A) of pivotation.

21. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention is explained in more detail in the following on the basis of preferred embodiments with reference to the accompanying partly schematic drawings, in which the same or corresponding parts or sections are provided with the same reference signs and in which:

[0041] FIG. 1 shows a perspective view of a fine-processing machine, which is equipped in accordance with the invention, for optical workpieces obliquely from above and the front left, with a view into a work space of the fine-processing machine and onto a device according to the invention for fine-processing of an axicon, the axicon being mounted thereat on an end of a tool spindle which is upper in FIG. 1 and which faces a workpiece spindle, which is lower in FIG. 1, in a pivotable yoke of the fine-processing machine;

[0042] FIG. 2 shows a plan view of the fine-processing machine, which is shown in FIG. 1, from above in FIG. 1;

[0043] FIG. 3 shows a perspective view, which is increased in size relative to the scale of FIGS. 1 and 2, of separately depicted subassemblies of the fine-processing machine according to FIG. 1 obliquely from above and the front left, namely of a vertical carriage with the tool spindle and of the yoke with the workpiece spindle as well as the device, which is arranged therebetween, for fine-processing of an axicon, wherein a substantially triangular tool, which is driven to linearly oscillate, of the device is disposed in processing engagement with a rotationally driven concave axicon mounted on the workpiece spindle;

[0044] FIG. 4 shows a perspective view of separately depicted subassemblies of the fine-processing machine according to FIG. 1 obliquely from above and the front left, which perspective view is again increased in size relative to the scale of FIG. 3 and differs from the view according to FIG. 3 merely in that the vertical carriage with the tool spindle was omittedapart from the clamping chuck thereofso as to expose a view of the device for fine-processing of an axicon;

[0045] FIG. 5 shows a perspective view, which is again increased in size relative to the scale of FIG. 4, of the device for fine-processing of an axicon according to FIG. 1 obliquely from below and the front left, which deviceapart from the clamping chuck of the tool spindleis shown separately from the fine-processing machine according to FIG. 1;

[0046] FIG. 6 shows a side view of the device, which is shown in FIG. 5, for fine-processing of an axicon;

[0047] FIG. 7 shows an underneath view of the device, which is shown in FIG. 5, for fine-processing of an axicon, from below in FIG. 6;

[0048] FIG. 8 shows a back view of the device, which is shown in FIG. 5, for fine-processing of an axicon, from the left in FIG. 6;

[0049] FIG. 9 shows a sectional view, which is to enlarged scale by comparison with FIG. 8, of the device, which is shown in FIG. 5, for fine-processing of an axiconwithout the clamping chuck of the tool spindlein correspondence with the section line IX-IX in FIG. 8, wherein the way in which the tool can be mounted on the device to be offset is illustrated in a lower part of FIG. 9;

[0050] FIGS. 10 to 15 show schematic underneath views of the device, which is shown in FIG. 5, for fine-processing of an axicon, similar to the underneath view according to FIG. 7 and illustrating some of the possibilities of how the axial position and the stroke of the tool, which is indicated in dashed lines, in oscillation direction can be influenced;

[0051] FIG. 16 shows a perspective view of another, substantially strip-shaped tool for the device, which is shown in FIG. 5, for fine-processing of an axicon, obliquely from above and the front right;

[0052] FIG. 17 shows a back view of the tool according to FIG. 16, from behind in FIG. 16;

[0053] FIG. 18 shows a side view of the tool according to FIG. 16, from the right in FIG. 17;

[0054] FIG. 19 shows a plan view of the tool according to FIG. 16, from above in FIG. 17;

[0055] FIG. 20 shows a schematic plan view of a concave axicon which is processed in accordance with the invention by means of the substantially triangular tool shown in FIG. 5;

[0056] FIG. 21 shows a schematic sectional view of the concave axicon and triangular tool, which are shown in FIG. 20, in correspondence with the section line XXI-XXI in FIG. 20;

[0057] FIG. 22 shows a schematic plan view of a concave axicon, which is processed in accordance with the invention by means of the substantially strip-shaped tool shown in FIGS. 16 to 19; and

[0058] FIG. 23 shows a schematic sectional view of the concave axicon and strip-shaped tool, which are shown in FIG. 22, in correspondence with the section line XXIII-XXIII in FIG. 22.

[0059] With regard to the drawings it may be additionally mentioned at this point that the illustration of the fine-processing machine equipped in accordance with the invention is in a right-angled cartesian co-ordinate system in which the letter x denotes the width direction, the letter y denotes the length direction and the letter z denotes the height direction of the fine-processing machine. In FIGS. 1 and 2 in order to expose a view of essential components or subassemblies of the fine-processing machine and to simplify the illustration, the control unit and control, cladding parts, door mechanisms and panels, deposits for workpieces and tools, the supply devices (inclusive of lines, hoses and pipes) for current, compressed air and polishing medium, the polishing medium return as well as the machine-internal measurement, maintenance and safety devices, in particular, were omitted because they do not appear necessary for an understanding of the invention and are in any case familiar to the expert.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0060] In FIGS. 1 and 2 there is denoted generally by the reference numeral 12as a possible case of use or place of action of a device 10, which is explained in more detail further below particularly with reference to FIGS. 3 to 15, for fine-processing of an axicon L, which according to FIGS. 20 to 23 has at least one concave (or alternatively convex) cone surface KF with a cone axis KA and a cone angle a CNC-controlled fine-processing machine, i.e. a machine for processing the surfaces and edges of optical workpieces by grinding, precision-grinding and/or polishing. The basic construction of this fine-processing machine 12 is explained in detail in German Patent DE 100 29 967 B4 of the present applicant, for which reason the fine-processing machine 12 shall be described in the following only to the extent appearing necessary for an understanding of the present invention. For the rest and for avoidance of repetition regard may be given and reference made at this pointwith respect to the construction and function of a fine-processing machine 12expressly to patent publication DE 100 29 967 B4.

[0061] The fine-processing machine 12 comprises in general a tool spindle 14 with a tool axis C of rotation, which is controlled in rotational speed, and a workpiece spindle with a workpiece axis D of rotation, which is regulated in rotational angle. The tool spindle 14 and the workpiece spindle 16 project into a work space 18 bounded by a machine bed 20 formed from polymer concrete. In that case, the tool spindle 14 and the workpiece spindle 16as will be similarly described in more detail in the following(inter alia) are movable (linear axis Y, linear axis Z) relative to one another, under positional regulation, in a notional plane Y-Z spanned by the tool axis C of rotation and the workpiece axis D of rotation, as well as pivotable, under regulation in rotational angle, relative to one another with respect to a pivot axis (A axis) extending perpendicularly to the plane Y-Z. The device 10 for fine-processing of axicons L is mounted on an end of the tool spindle 14, which faces the workpiece spindle 16.

[0062] For this purpose the device 10 comprises in general a base 22 or base plate, which is adapted to be flange-mounted on the tool spindle 14 of the fine-processing machine 12. Mounted on the base 22 is a guide arrangement 24 which guides in longitudinal movement a tool carriage 26 drivable to oscillate along an oscillation axis R. The tool carriage 26 itself carries a tool W1 or W2 for fine-processing of axicons L.

[0063] FIGS. 1 to 15, 20 and 21 show the tool W1 in accordance with a first variant, in which the tool W1 as seen in plan view has substantially the form of an isosceles triangle. This tool W1 has a processing region BB, which has a front end EB at a tip of the triangle and permits, on each of mutually opposite longitudinal sides of the triangle, linear engagement LE (cf. FIG. 20) with the cone surface KF to be processed of the axicon L.

[0064] By contrast, FIGS. 16 to 19, 22 and 23 show the tool W2 in accordance with a second variant in which the tool W2 is substantially strip-shaped. This tool W2 has a processing region BB, which has a front end EB at a transverse side of the tool W2 and permits, along a longitudinal side of the tool W2, linear engagement LE (see FIG. 23) with the cone surface KF to be processed of the axicon L.

[0065] Apart from the possibility of linear engagement LE of the respective processing region BB with the cone surface KF of the axicon L to be processed, it is common to the tools W1 and W2 that the respective processing region BB is provided with a commercially available polishing medium carrier (not shown in the figures). The polishing medium carrier can be, for example, a so-called polishing foil or, however, also a suitable foam with or without carrier material, which is glued onto the processing region BB of the tool W1, W2 with a certain degree of lateral protrusion and with the assistance of a commercially available adhesive. Polishing foils usable here are, for example, of polyurethane (PUR) in a thickness of 0.5 to 1.3 millimeters obtainable from the company James H. Rhodes & Company, Vernon, United States, whilst suitable foams can be acquired from, for example the company Getzner Werkstoffe GmbH, Oberhaching, Germany. A commercially available adhesive of the brand Pattex (Registered Trade Mark) of the company Henkel AG & Co. KGaA, Dusseldorf, Germany, for example, is suitable for gluing these polishing medium carriers onto the processing region BB of the respective tool W1, W2.

[0066] Returning to FIGS. 1 and 2 after this general overview of the fine-processing machine 12, the device 10 mounted thereon for the fine-processing of axicons L and the tool W1, W2 moved therewith, it can additionally be observed with respect to the fine-processing machine 12 that the machine bed 20 thereof has two parallel side walls 28 between which the work space 18 is formed. The side walls 28 mount a portal 30 which is movable under positional regulation along the linear axis Y in the longitudinal direction y of the fine-processing machine 12. A horizontal carriage 32 is guided to be longitudinally displaceable at the portal 30 in the width direction x of the fine-processing machine 12 and can be moved under positional regulation along the linear axis X. A vertical carriage 34 is in turn guided to be longitudinally displaceable at the horizontal carriage 32 in the height direction z of the fine-processing machine 12, the vertical carriage being movable under positional regulation along the linear axis Z and carrying the tool spindle 14.

[0067] As far as the workpiece side is concerned, a yoke 36 carrying the workpiece spindle 16 is provided in the work space 18. The yoke 36 is mounted on the side walls 28 of the machine bed 20 to be rotatable about the pivot axis A and can, under regulation, be driven or held in rotational angle by means of a torque motor and associated brake (not visible in the figures). Counterweights 38 provided at both sides in that case ensure weight compensation for the yoke 36.

[0068] The tool spindle 14 and the workpiece spindle 16 are provided, finally, at each of the mutually facing ends thereof with a respective clamping chuck 40 or 42, which can be constructed to be of, for example, hydro-expansion configuration. A cylindrical shank of a tool (not shown) can be held in a manner known per se by the clamping chuck 40 of the tool spindle 14. The clamping chuck 42 of the workpiece spindle 16 is constructed for the purpose of gripping and holding an optical workpiece, in the present application an axicon L, at a cylindrical edge surface RF of the axicon L (cf. FIGS. 20 to 23).

[0069] With regard to the kinematics of the fine-processing machine 12 it is evident in that respect to the expert that at the tool side the end, which projects into the work space 18, of the tool spindle 14 can be spatially moved and positioned in the work space 18 by means of the three linear axes X, Y and Z. In addition, the clamping chuck 40 can be driven by means of the tool spindle 14 to rotate about the tool axis C of rotation. At the workpiece side the end, which projects into the work space 18, of the workpiece spindle 16 can be adjusted or pivoted, defined in angle, with respect to the tool spindle 14 by means of the pivot axis A. Moreover, the clamping chuck 42 can be driven by means of the workpiece spindle 16 to rotate about the workpiece axis D of rotation and located in angular position.

[0070] Further details of the device 10 for fine-processing of axicons L can be inferred from FIGS. 3 to 9. As at the outset can be best recognized in FIGS. 4, 5 and 9, the base 22 has a circularly round hole 44 through which, in the state of the device 10 being mounted on the tool spindle 14, the work-space end of the tool spindle 14 with the clamping chuck 40 projects. In that case, the upper side of the base 22 forms a flat flange surface which can be placed from below against a spindle housing of the tool spindle 14. Provided for securing the base 22 to the tool spindle 14 in the illustrated embodiment are two securing screws 46 (see FIG. 4) which in the mounted state of the device 10 pass through associated fastening holes in the base 22 and are screwed into associated threaded bores (not shown) in the spindle housing of the tool spindle 14.

[0071] The guide arrangement 24, which is mounted on the base 22, for the tool carriage 26 comprises a guide frame 48 which is rectangular as seen in plan view and which is secured to the base 22 by way of securing brackets 50, which are arranged at the corners of the guide frame 48, with the assistance of screws so that the guide frame 48 extends parallel to and at a spacing from the base 22. Guide rails 52 for the tool carriage 26 are mounted by means of screws on the guide frame 48 at mutually opposite sides. As can be best recognized in FIGS. 5 and 8, the guide rails 52, which consist of a slide-bearing material, have a respective substantially V-shaped groove 54 on each of mutually facing sides, whilst the tool carriage 26 has a respective wedge-shaped guide section 56 on each of mutually remote sides, the wedge-shaped guide sections 56 of the tool carriage 26 being slidably received in the V-shaped grooves 54 of the guide rails 52. It will be apparent that the tool carriage 26 can thus be reciprocatingly moved in the guide frame 48 (oscillation axis R).

[0072] Provided in the illustrated embodiment for the oscillating drive of the tool carriage 26 is a transmission mechanism 58 which is adapted to convert a rotational movement, which is produced by the tool spindle 14 of the fine-processing machine 12, into a reciprocating linear movement of the tool carriage 26 along the oscillation axis R. For this purpose the transmission mechanism 58 is configured in the manner of an eccentric drive and comprises a rotary disc 60 which is drivably connectable with the tool spindle 14 of the fine-processing machine 12 and is rotatable about an axis of rotation, here the tool axis C of rotation. As FIG. 9 shows, the rotary disc 60 has a cylindrical clamping projection 62 or clamping pin by way of which the rotary disc 60 can be clamped to the clamping chuck 40 of the tool spindle 14.

[0073] A guide pin 64 is mounted on the rotary disc 60 to be radially offset with respect to the axis C of rotation, the pin engaging in a slot 66 which is formed in the tool carriage 26 and which extends transversely to the movement direction of the tool carriage 26, thus to the oscillation axis R. As evident from FIGS. 9 to 13, a center axis of the guide pin 64 thus has a radial spacing r1 from the axis C of rotation of the rotary disc 60.

[0074] FIGS. 10 and 11 also illustrate what takes place in this embodiment of the transmission mechanism 58 when the rotary disc 60 rotates through 180 about the axis C of rotation from its rotational angle setting according to FIG. 10, so that it reaches the rotational angle setting according to FIG. 11 and, in particular, the tool carriage 26which is constrainedly guided between the guide rails 52 of the guide arrangement 24is thereby moved due to the interlocking engagement of the guide pin 64 with the slot 66 of the tool carriage 26 from the lefthand axial position, which is illustrated in FIG. 10, of the tool carriage 26 in the guide frame 48 to the right through a stroke H1 into the righthand axial position, which is illustrated in FIG. 11, of the tool carriage 26 in the guide frame 48. In that case, the stroke H1 of the tool carriage 26 is twice as large as the radial spacing r1 between the guide pin 64 and the axis C of rotation of the rotary disc 60.

[0075] If the rotary disc 60 is then further rotated out of its rotational angle setting according to FIG. 11 through 180 about the axis C of rotation so that it again reaches its rotational angle setting according to FIG. 10, the tool carriage 26 moves, by virtue of the mechanically positive engagement of the guide pin 64 with the slot 66, from the righthand axial position, which is illustrated in FIG. 11, of the tool carriage 26 in the guide frame 48 to the left through the stroke H1 back into the lefthand axial position, which is illustrated in FIG. 10, of the tool carriage 26 in the guide frame 48. It will be apparent that in this way a rotation of the rotary disc 60 about the axis C of rotation in the guide frame 48 constrains an oscillatory reciprocating movement of the tool carriage 26 with a predetermined stroke H1 along the oscillation axis R.

[0076] As can be best seen in FIG. 9, the rotary disc 60 in the illustrated embodiment is provided with a plurality of securing bores 68, 70, 72 for the guide pin 64. Each of these securing bores 68, 70, 72 is here formed as a threaded bore into which the guide pin 64 can be screwed by a threaded projection 74. The center axes of the securing bores 68, 70, 72 have a different radial spacing r1, r2, and r3, respectively, from the axis C of rotation so that a stroke H1, H2 or H3 of the tool carriage 26, which is settable in stages, in the guide frame 48 arises through displacement of the guide pin 64.

[0077] In the illustrated embodiment the tool carriage 26 is additionally provided with a further slot 76, which extends parallel to the slot 66. The guide pin 64 can be selectably brought into engagement with one or other slot 66, 76, whereby an axial relative position of the tool carriage 26 with respect to the axis C of rotation of the rotary disc 60 is settable in two stages.

[0078] FIGS. 12 and 13 illustrate this by comparison with FIGS. 10 and 11 for the case that the guide pin 64 is not displaced at the rotary disc 60, i.e. is again secured by its threaded projection 74 in the securing bore 68, but on the other hand is brought by its free end into engagement with the other slot 76 in the tool carriage 26. In this case as well, rotation of the rotary disc 60 about the axis C of rotation produces an oscillatory reciprocating movement of the tool carriage 26 with the stroke H1 in the guide frame 48 (see FIG. 13), but this with axial end positions of the tool carriage 26 different from the axial end positions with the slot engagement in accordance with FIGS. 10 and 11. Resulting therefrom for the two axial end positions of the tool carriage 26compared with the basic configuration according to FIGS. 10 and 11is a respective offset V3 or V4 of the front end EB of the tool W1, which is drivably connected with the tool carriage 26, indicated in FIGS. 10 to 15 by dashed lines.

[0079] Illustrated in FIGS. 14 and 15 is a combination of the afore-described adjustment measures, namely change of the stroke H1, H2, H3 of the tool carriage 26 by displacing the guide pin 64 in the securing bores 68, 70, 72 of the rotary disc 60, and changing the axial start and reversal positions of the tool carriage 26 in the guide frame 48 by selection of a different slot 66, 76 of the tool carriage 26 for the engagement with the guide pin 64. In this case, by comparison with FIGS. 10 and 11 the guide pin 64 is in engagement with the other slot 76 of the tool carriage 26, but compared with FIGS. 12 and 13 it is at the same time also screwed into a different securing bore 70 in the rotary disc 60. Thus, by comparison with the settings according to FIGS. 10 to 13 the result is a larger stroke H2 and different axial start and reversal positions of the tool carriage 26, as is apparent from a vertical comparison of FIGS. 10, 12 and 14 and FIGS. 11, 13 and 15, which show guide frames 48 aligned for that purpose. The result here is an offset V5 or V6 at the front end EB of the tool W1 for the two axial end positions of the tool carriage 26.

[0080] It may also be mentioned at this point that the guide frame 48 is provided at its short side with slot-like openings 78 which are so dimensioned that the tool carriage 26, depending on its stroke H1, H2, H3 and/or its axial relative position with respect to the axis C of rotation of the rotary disc 60, in the case of its reciprocating movement in the guide frame 48 is optionally capable of entering one of the openings 78, which is not, however, shown in the figures.

[0081] As can be further inferred particularly from FIG. 9, a block-shaped connecting part 80 for the tool W1 or W2 at the tool carriage 26 is secured on the side, which is remote from the rotary disc 60, of the tool carriage 26. For that purpose, three securing bores 82 with an internal thread are formed in the tool carriage 26 in the illustrated embodiment, the bores lying one after the other with the same spacing from one another as seen along the oscillation axis R, whilst the connecting part 80 has two associated blind bores 84 with an internal thread. Grub screws 86 are screwed into two adjacent securing bores 82 of the tool carriage 26 and extend into the blind bores 84 of the connecting part 80 so as to fix the connecting part 80 to the tool carriage 26.

[0082] Since threeor optionally even moresecuring bores 82 are provided in the tool carriage 26 the connecting part 80 can be variably secured, in its axial position along the oscillation axis R, to the tool carriage 26. This in turn has an influence on which axial relative position the tool W1 or W2 adopts, as seen along the oscillation axis R, with respect to the axis C of rotation of the rotary disc 60. In FIGS. 10 to 15 the grub screws 86 are indicated by solid circles; the axial position of the connecting part 80 with respect to the tool carriage 26 here corresponds with the grouping shown in FIG. 9.

[0083] It can also be recognized in FIG. 9 that the connecting part 80 is provided with a further guide arrangement 88 which serves the purpose of guiding the tool W1, W2 to be movable in a direction transverse to the oscillation axis R of the tool carriage 26. In the illustrated embodiment the further guide arrangement 88 comprises two guide cylinders 90 which respectively extend perpendicularly to the oscillation axis R and parallel to one another. In that regard, each guide cylinder 90 comprises a cylinder bore 92, which is formed as a blind bore, in the connecting part 80 and a cylinder pin 94 received in the manner of a piston in the respective cylinder bore 92 to be axially displaceable.

[0084] Each cylinder pin 94 is provided at its end facing the tool carriage 26 with an oblong hole 96. In addition, threaded bores 98, which extend transversely to the cylinder bores 92 and into each of which a respective cap screw 100 penetrating the oblong hole 96 in the associated cylinder pin 94 is screwed, are formed in the connecting part 80 in the proximity of the closed ends of the cylinder bores 92. It will be apparent that the combination of oblong hole 96 and cap screw 100 allows a limited axial displacement of the respective cylinder pin 94 in the associated cylinder bore 92, yet the cap screws 100 prevent the cylinder pins 94 from being able to be withdrawn from the cylinder bores 92.

[0085] Each cylinder pin 94 has at its end remote from the tool carriage 26 a blind bore 102which is formed at the end facewith an internal thread into which a securing screw 104, here executed as a countersunk-head screw, for the tool W1 or W2 is screwed. Each tool W1 or W2 has several, in the illustrated embodiments in each instance four, screw holes 106 which in longitudinal direction of the respective tool W1 or W2 are arranged on a line at the same spacing from one another. The tool W1, W2 can thus be mounted on the further guide arrangement 88, more precisely the cylinder pins 94 thereof, to be variable in its axial position along the oscillation axis R, wherein the securing screws 104 respectively penetrate adjacent screw holes 106 in the respective tool W1 or W2.

[0086] This further axial adjustment possibility for the tool W1 or W2 is illustrated in FIG. 9 by way of example for the triangular tool W1. Starting from a basic configuration in which the tool W1 is mounted on the guide arrangement 88 in a central position by means of the securing screws 104, which extend through the central screw holes 106 of the tool W1, the tool W1 can thus be secured to the guide arrangement 88 further forwardly (as shown centrally in FIG. 9) or further rearwardly (illustrated below in FIG. 9) for a specific axial position of the tool carriage 26 in the guide frame 88 as seen along the oscillation axis R. An offset V1 or V2 at the front end EB of the tool W1, by comparison with the basic configuration according to the upper part of FIG. 9, results therefrom.

[0087] Finally, the respective tool W1, W2 is additionally loaded in the direction transverse or perpendicular to the oscillation axis R of the tool carriage 26 by a force which urges the tool W1 or W2 away from the connecting part 80. In the illustrated embodiment this force is applied by mutually repelling magnets 108 arranged between the connecting part 80 and the tool W1 or W2. During the actual polishing process these magnets 108 ensure that polishing pressure at the processing region BB of the respective tool W1, W2 is not excessive.

[0088] More precisely, the magnets 108 are arranged, as can be recognized in FIGS. 6, 8, 9 and 16 to 19, at the respective tool W1 or W2 on the side thereof, which faces the tool carriage 26, between the screw holes 106 and in a line with the screw holes 106. A magnet 108 is arranged at the connecting part 80 on the end, which faces the respective tool W1 or W2, of the connecting part 80 between the cylinder bores 92 and on a line with the cylinder bores 92, here at an insert 110 in the connecting part 80. In every case the respective magnet 108 is received in an associated recess and suitably secured, for example by means of an adhesive.

[0089] It is apparent from the preceding description that with the assistance of the device 10 equipped with one of the tools W1, W2 and with use of geometrically indeterminate cutting edges in the form of bound or loose grain in combination with a liquid at the processing region BB of the tool W1 or W2 it is possible to perform a method for fine-processing of an axicon L in which by means of the tool W1 or W2 a material removal at the cone surface KF of the axicon L is produced by a relative cutting speed which arises solely from a) a rotational movementhere produced by the workpiece axis D of rotation of the workpiece spindle 16of the axicon L about the cone axis KA, and b) a relative oscillating linear movementhere produced by way of the oscillation axis R of the device 10of the tool W1 or W2 in that case disposed in linear engagement LE with the cone surface KF to be processed, in which the front end EB of the processing region BB as seen in a plan view moves back and forth in radial direction with respect to the cone axis KA.

[0090] This tool engagement with combined motions of tool and workpiece is illustrated in FIGS. 20 and 21 for the triangular tool W1 and in FIGS. 22 and 23 for the strip-shaped tool W2, in both cases at an axicon L with a concave cone surface KF. In that regard, through the use of thicker lines FIGS. 20 and 23 illustrate the linear engagement LE of the respective tool W1 (here double, on both sides of the tool W1) or W2 (here single, on the lower side of the tool W2) with the cone surface KF, which is to be subjected to fine-processing, of the axicon L. In the case of an axicon with a convex cone surface, the strip-shaped tool W2 would be used with its tool lower contact line, because the triangular tool W1 would not be capable of contacting a convex cone surface as shown in FIG. 20.

[0091] When carrying out the afore-described method for fine-processing of an axicon L initially a relative alignment and adjustment movement is produced between the axicon L and the tool W1 or W2 in accordance with the cone angle , as a consequence of which the processing region BB of the tool W1 or W2 enters into the linear engagement LE with the cone surface KF of the axicon L, in which case the front end EB of the processing region BB faces the cone axis KA. It will be apparent to the expert that the angular alignment movement with the afore-described fine-processing machine 12 takes place at the workpiece side by means of the pivot axis A at the yoke 36 carrying the workpiece spindle 16. Equally, it will be apparent that on the other hand the spatial adjustment movement with the afore-described fine-processing machine 12 takes place at the tool side by way of the three linear axes X, Y, Z associated with the tool spindle 14.

[0092] If the biased linear engagement LE, which is defined by means of the magnets 108 at the connecting part 80 and the respective tool W1 or W2, between the tool W1 or W2 and the cone surface KF, which is to be finely processed, of the axicon L is produced, thenby means of the tool spindle 14, the rotary disc 60 clamped thereto and the transmission mechanism 58 of the device 10 as described in the foregoingthere is generated between the axicon L, which is driven by way of the workpiece axis D of rotation of the workpiece spindle 16 to rotate about the cone axis KA, and the tool W1 or W2 the relative oscillatory linear movement (oscillation axis R) as an advance movement in which the front end EB of the processing region BB during a revolution of the axicon L about the cone axis KA as seen in plan view moves multiple times over the cone surface KF from an outer edge region RB of the cone surface KFin a direction which is radial with respect to the cone axis KAat least into the proximity of the cone axis KA and back again.

[0093] During the fine-processing of the cone surface KF, thenby way of the workpiece spindle 16a rotational speed of the axicon L about the cone axis KA andby means of appropriate rotational speed control of the tool spindle 14a frequency of the relative oscillatory linear movement (oscillation axis R) of the tool W1 or W2 over the cone surface KF can be matched to one another in such a way that the number of reciprocating movements of the tool W1 or W2 per revolution of the axicon L is not even-numbered. A continuous track change of the oscillating tool W1 or W2 on the fine-processed cone surface KF of the rotating axicon L thus arises. In tests carried out by the inventors very good fine-processing results could be achieved with a ratio of frequency to rotational speed in which during the fine-processing of the cone surface KF the number of reciprocating movements of the tool W1 or W2 per revolution of the axicon L about the cone axis KA was greater than or equal to three and less than or equal to seven.

[0094] The fine-processing machine 12, which is shown in FIGS. 1 and 2 and known per se and on the tool spindle 14 of which the device 10 explained above in detail is mounted, can thus be used in the afore-described mode and manner for fine-processing of an axicon L having at least one concave or convex cone surface KF with a cone axis KA and a cone angle .

[0095] In a method for fine-processing of an axicon having a concave or convex cone surface with a cone axis and a cone angle, with use of geometrically indeterminate cutting edges in the form of bound or loose grain in combination with a liquid at a processing region of a tool, which is constructed for linear engagement with the cone surface and has an end at the front with respect to the cone axis, there is produced at the cone surface a material removal by a relative cutting speed which arises solely from a rotational movement of the axicon about the cone axis and a relative oscillating linear movement (oscillation axis) of the tool, in which the processing region is in linear engagement with the cone surface and its front end as seen in plan view moves back and forth in a direction radial with respect to the cone axis. In addition, a device usable for this method and mountable on a tool spindle of a fine-processing machine is disclosed.

REFERENCE NUMERAL LIST

[0096] 10 device for fine-processing of axicons [0097] 12 fine-processing machine [0098] 14 tool spindle [0099] 16 workpiece spindle [0100] 18 work space [0101] 20 machine bed [0102] 22 base [0103] 24 guide arrangement [0104] 26 tool carriage [0105] 28 side wall [0106] 30 portal [0107] 32 horizontal carriage [0108] 34 vertical carriage [0109] 36 yoke [0110] 38 counterweight [0111] 40 clamping chuck [0112] 42 clamping chuck [0113] 44 hole [0114] 46 securing screw [0115] 48 guide frame [0116] 50 securing bracket [0117] 52 guide rail [0118] 54 V-shaped groove [0119] 56 wedge-shaped guide section [0120] 58 transmission mechanism [0121] 60 rotary disc [0122] 62 clamping projection [0123] 64 guide pin [0124] 66 slot [0125] 68 securing bore [0126] 70 securing bore [0127] 72 securing bore [0128] 74 threaded projection [0129] 76 slot [0130] 78 opening [0131] 80 connecting part [0132] 82 securing bore [0133] 84 blind bore [0134] 86 grub screw [0135] 88 guide arrangement [0136] 90 guide cylinder [0137] 92 cylinder bore [0138] 94 cylinder pin [0139] 96 oblong hole [0140] 98 threaded bore [0141] 100 cap screw [0142] 102 blind bore [0143] 104 securing screw [0144] 106 screw hole [0145] 108 magnet [0146] 110 insert [0147] r1 radial spacing [0148] r2 radial spacing [0149] r3 radial spacing [0150] x width direction [0151] y length direction [0152] z height direction [0153] cone angle [0154] A pivot axis of workpiece (controlled in rotational angle) [0155] BB processing region [0156] C tool axis of rotation (regulated in rotational speed)/axis of rotation [0157] D workpiece axis of rotation (controlled in rotational angle) [0158] EB front end [0159] H1 stroke [0160] H2 stroke [0161] H3 stroke [0162] KA cone axis [0163] KF cone surface [0164] L lens/axicon [0165] LE linear engagement [0166] R oscillation axis [0167] RB edge region [0168] RF edge surface [0169] V1 offset [0170] V2 offset [0171] V3 offset [0172] V4 offset [0173] V5 offset [0174] V6 offset [0175] W1 triangular tool [0176] W2 strip-shaped tool [0177] X linear axis of tool (controlled in position) [0178] Y linear axis of tool (controlled in position) [0179] Z linear axis of tool (controlled in position)