JP2005186222A - Cutting method in wire saw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting method in a wire saw, restraining a cut surface from being in the inclined state on the cutting start part side of a work and improving the cut machining accuracy. <P>SOLUTION: A wire 18 circulated around a plurality of machining rollers 15, 16, 17 is reciprocated to travel in a predetermined stroke, and an outgoing stroke is set longer than the returning stroke, whereby the wire is fed and traveled in one direction as a whole, thereby cutting the work 22. In this case, at the start of cutting the work 22, the wire 18 is traveled either in the outgoing direction or in the returning direction in a longer stroke than the predetermined stroke, thereby cutting the cutting start part of the work. After that, traveling of the wire 18 is switched to the reciprocating traveling in the predetermined stroke to continue cutting the work. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a workpiece cutting method in a wire saw that uses a wire to cut a workpiece made of a hard and brittle material such as a semiconductor material, a magnetic material, or ceramic.

Conventionally, as this type of wire saw, for example, a structure as disclosed in Patent Document 1 is known. That is, in this conventional configuration, as shown in FIG. 6, one wire 42 is circulated between a plurality of processing rollers 41. The wire 42 is reciprocated at a predetermined stroke, and the forward stroke is set longer than the backward stroke, so that the wire 42 is fed in one direction from the feed side 42a toward the feed side 42b as a whole. The During the traveling of the wire 42, slurry containing loose abrasive grains is supplied onto the wire, and the workpiece 43 is pressed against the wire in this state, whereby the workpiece 43 is cut. ing.
Japanese Patent Laid-Open No. 10-329000

  However, when the workpiece 43 is cut using this conventional wire saw, as shown in FIG. 7, at the cutting start portion 43 a of the workpiece 43, the cutting surface 44 by the wire 42 is in the axial direction of the workpiece 43. It is formed in an inclined state so as to flow to one side. Further, in the cutting end portion 43b of the work 43, the cutting surface 44 is formed in an inclined state in the work 43 in the direction opposite to the cutting start portion 43a with respect to the axial direction. Therefore, there has been a problem that the cutting accuracy with respect to the workpiece 43 is significantly reduced.

  In order to cope with such problems, various countermeasures have been tried conventionally. As a result, when machining the cut end portion 43b of the work 43, there is also an influence of thermal expansion or the like, and the cut end portion 43b is cooled by lowering the temperature of the slurry than usual and cooling the machined portion at a low temperature. The occurrence of the inclined state of the cut surface 44 in FIG. However, at the cutting start portion 43a of the work 43, the cutting surface 44 is still in an inclined state, causing a reduction in cutting processing accuracy. The reason why the cutting start portion 43a is inclined is that the wire 42 is reciprocated so that the wire 42 is easily moved to the left and right, and the wire 42 is stopped once when the traveling direction of the wire is switched. It is presumed that a cutting groove that is generated and a force is applied to the work 43 in one traveling direction of the wire 42 and flows in a direction offset from the cut end is formed.

  The present invention has been made paying attention to such problems existing in the prior art. The purpose is to prevent the cutting surface from inclining on the cut start part side of the workpiece, so that a straight cut groove can be formed in the cut edge, and the straight groove is cut as it is in the subsequent reciprocating cutting. It is possible to provide a cutting method in a wire saw that can improve the cutting accuracy.

  In order to achieve the above object, according to the first aspect of the present invention, the wire wound between the plurality of processing rollers is reciprocated at a predetermined stroke, and the forward stroke is made longer than the backward stroke. Thus, in the wire saw in which the workpiece is fed and traveled in one direction as a whole and the workpiece is relatively fed in the contact direction with respect to the traveling wire to cut the workpiece, the wire is moved at a stroke longer than the predetermined stroke at the start of cutting. Traveling in one direction of the forward direction or the backward direction is performed to perform cutting of a work cutting start portion, and thereafter, the traveling of the wire is switched to the reciprocating traveling of the predetermined stroke to continue the cutting of the work. .

  According to a second aspect of the present invention, in the first aspect, before starting cutting, the wire is continuously moved in the forward direction with a stroke longer than the predetermined stroke without contacting the workpiece, and then the wire is moved by the same distance. Only the workpiece is moved in the backward direction while being in contact with the workpiece to cut the cutting start portion, and then the wire is moved in the forward direction by the same distance while being separated from the workpiece, and then the wire is reciprocated. It is characterized by shifting to cutting by.

  According to a third aspect of the present invention, in the first aspect, the wire is caused to travel in the forward direction to perform the cutting of the cutting start portion, and subsequently, the cutting is performed by the reciprocating traveling of the wire. .

  In invention of Claim 4, in any one of Claims 1-3, in the cutting of the said cutting start part, it cuts 5 mm or less more than the depth equivalent to the diameter of a wire at least. Features.

  In invention of Claim 5, in any one of Claims 1-4, the travel distance to the one direction of the wire in the cutting of the said cutting start part exists in the range of 500m-5000m. It is characterized by that.

(Function)
In the first to third aspects of the invention, when the workpiece starts to be cut, the wire is allowed to travel in one direction to cut the work starting portion of the workpiece, thereby preventing the wire from moving in the left-right direction. In addition, the screw action of the wire can be suppressed to prevent the cut surface from being inclined on the side where the workpiece starts to be cut, and a straight cut groove can be formed. Therefore, in the subsequent cutting by reciprocating, it can be cut into a straight groove as it is, and the workpiece cutting accuracy can be improved.

  In the invention according to claim 4, by cutting at least a depth corresponding to the diameter of the wire and cutting 5 mm or less by cutting at the cutting start portion, the wire is removed from the cutting groove at the start of cutting by reciprocating travel thereafter. The cutting direction of the workpiece by the wire can be determined in a direction orthogonal to the axial direction of the workpiece, and the cutting surface on the cutting start portion side can be prevented from being inclined.

  In the invention according to claim 5, the wire is made to sufficiently cut and enter the cutting start portion of the workpiece by running the wire in one direction within a range of 500 m to 5000 m by cutting the cutting start portion. Therefore, it is possible to reliably prevent the cutting surface on the cutting start portion side from being inclined.

  As described above, according to the present invention, it is possible to suppress the cutting surface from being inclined at the cutting start portion of the workpiece, and the effect that the cutting accuracy can be improved is exhibited.

(First embodiment)
A wire saw according to a first embodiment of the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 and 2, a column 12 is erected on the apparatus base 11. A cutting mechanism 13 is installed on one side of the column 12 via a bracket 14. The cutting mechanism 13 includes a plurality of processing rollers 15, 16, and 17 that extend in parallel at predetermined intervals, and annular grooves 15 a, 16 a, and 17 a are formed at a predetermined pitch on the outer periphery thereof. In the drawings, the number of the annular grooves 15a, 16a, and 17a is drawn smaller than the actual number for easy understanding.

  In each of the annular grooves 15a, 16a, and 17a of the processing rollers 15, 16, and 17, a wire 18 made of a single wire is continuously wound. The bracket 14 is provided with a wire traveling motor 19 whose rotation direction can be changed, and the processing rollers 15, 16, and 17 are rotated by the motor 19 via a transmission mechanism (not shown). The wire 18 is reciprocated with a predetermined stroke by the rotation of the processing rollers 15, 16, and 17. In this case, the forward stroke is set to be longer than the backward stroke, and for example, 10 m forward and 9 m backward are repeated, and the wire 18 is fed and traveled in one direction as a whole.

  A slurry supply mechanism 20 is disposed on the bracket 14 so as to extend in parallel with the processing rollers 15 to 17 above the cutting mechanism 13. Then, when the pump 20b is rotated by the pump motor 20a, an aqueous or oily slurry containing free abrasive grains is formed on the wire 18 between the pair of processing rollers 15 and 16 adjacent from the slurry supply mechanism 20. Is supplied. Above the slurry supply mechanism 20, a work support mechanism 21 is supported on the column 12 so as to be movable up and down, and a work 22 made of a hard and brittle material is detachably set below the work support mechanism 21. A workpiece lifting / lowering motor 23 is disposed on the column 12. The motor 23 moves the workpiece support mechanism 21 up and down via a ball screw or the like (not shown) so that the workpiece 22 is relatively fed in the contact direction with respect to the wire 18.

  During the operation of the wire saw, the workpiece support mechanism 21 is lowered toward the cutting mechanism 13 while the wire 18 travels between the processing rollers 15, 16, and 17 of the cutting mechanism 13. At this time, slurry containing loose abrasive grains is supplied from the slurry supply mechanism 20 onto the wire 18, and the workpiece 22 is pressed against and brought into contact with the wire 18, and the wafer is cut from the workpiece 22.

  A reel mechanism 24 is installed on the apparatus base 11 and includes a feeding reel 25 for feeding the wire 18 in the traveling direction and a take-up reel 26 for winding the wire 18. The apparatus base 11 is provided with a pair of reel rotation motors 27 and 28 each composed of a servo motor capable of changing the rotation direction and rotation speed. The reels 25 and 26 are connected to the motor shafts via a transmission mechanism (not shown). Are connected. The reels 25 and 26 are rotated in the forward and reverse directions in synchronism with the processing rollers 15, 16 and 17 by the forward and reverse rotation of the servo motor, and the wire 18 is wound and unwound as it reciprocates.

  A traverse mechanism 29 is installed on the apparatus base 11 adjacent to the reel mechanism 24 to traverse up and down the feeding of the wire 18 from the feeding reel 25 and the winding of the wire 18 onto the winding reel 26. While guiding. As the reels 25 and 26 of the reel mechanism 24 rotate, the wire 18 is fed from the feeding reel 25 to the cutting mechanism 13 and the processed wire 18 is wound on the take-up reel 26.

  A tension applying mechanism 30 and a guide mechanism 31 are arranged between the reel mechanism 24 and the cutting mechanism 13. Then, both ends of the wire 18 wound between the processing rollers 15, 16, and 17 of the cutting mechanism 13 are hooked on the tension applying mechanism 30 via the guide rollers 32 of the guide mechanism 31. In this state, a predetermined tension is applied to the wire 18 between the processing rollers 15, 16, and 17 by the tension applying mechanism 30.

Next, the circuit configuration of the wire saw will be described.
As shown in FIG. 3, the control circuit 34 includes a CPU 35, a ROM 36, a RAM 37, an operation unit 38, a wire traveling motor 19, a workpiece lifting / lowering motor 23, reel rotation motors 27 and 28, a slurry supply pump motor 20a, The display unit 39 is configured.

  The CPU 35 constitutes a control means and controls the entire control circuit 34. The ROM 36 stores a program for controlling the control circuit 34. The RAM 37 is composed of a flash memory or the like, and stores temporary data generated during program execution. The operation unit 38 includes various operation keys such as a numeric keypad 38a necessary for input and keys for starting and stopping the operation of the wire saw. The display unit 39 includes a monitor made up of an LCD or the like, and displays the state of the wire saw or data input by the numeric keypad 38a.

  The CPU 35 controls the motors 19, 23, 27, 28, and 20a so that the wire 18 travels in one direction with a stroke longer than the predetermined stroke during the reciprocating travel described above when the workpiece 22 starts to be cut. Let the cutting start part be cut. After that, the traveling of the wire 18 is switched to the reciprocating traveling of the predetermined stroke to continue the cutting of the workpiece 22.

  Next, the operation when the workpiece 22 is cut by the wire saw of this embodiment will be described based on the flowchart of FIG. This flowchart is executed under the control of the CPU 35 based on a program stored in the ROM 36.

  Now, when the operation of the wire saw is started, in step S1, the wire 18 is continuously moved in the forward direction with a stroke longer than the predetermined stroke in a state where the wire 18 remains separated without being in contact with the workpiece 22. In this case, it is desirable to set the travel distance within a range of 500 m to 5000 m. When the wire 18 travels in the forward direction for a predetermined distance, the workpiece 22 by the workpiece support mechanism 21 is lowered and brought into contact with the wire 18 and the slurry is supplied from the slurry supply mechanism 20 in S2. Is started.

  Next, in S <b> 3, the wire 18 continuously travels in the backward direction by the same distance as when traveling in the forward direction, and the workpiece 22 is cut and fed. As a result, the wire 18 is continuously run in the backward direction from the new line portion, and the cutting start portion of the workpiece 22 is cut, and a cut groove is formed in the workpiece 22. In the cutting of the cutting start portion, when the wire 18 is moved to the reciprocating travel described later, a depth not to be removed from the cutting groove, for example, a depth corresponding to at least the diameter of the wire 18 is formed. However, when the wire 18 travels for 5000 m and the cutting at the start of cutting is executed, a cutting groove having a sufficient depth (about 5 mm) is formed on the outer periphery of the workpiece 22. The thickness of the wire 18 is about 0.2 to 0.5 mm.

  Thereafter, when the wire 18 travels in the backward direction by a predetermined distance and the cutting at the beginning of cutting is completed, the lowering of the work 22 by the work support mechanism 21 is interrupted and the supply of the slurry from the slurry supply mechanism 20 in S4. Is interrupted. In S5, in a state where the machining feed of the workpiece 22 is stopped, the wire 18 is run in the forward direction by the same predetermined distance as described above, and the predetermined length of the wire 18 used for cutting at the cutting start portion is obtained. This portion is fed from the cutting mechanism 13 to the reel mechanism 24 side.

  Then, when the wire 18 travels idle by the predetermined distance, in S6, the travel of the wire 18 is switched to the reciprocating travel of the predetermined stroke. At the same time, the processing feed of the workpiece 22 by the workpiece support mechanism 21 is resumed, and the supply of slurry from the slurry supply mechanism 20 is resumed. Thereby, the wire 18 is reciprocatingly moved from the new line portion, is brought into contact with the workpiece 22, and cutting to the workpiece 22 is continued.

  As described above, in this embodiment, the wire 18 is continuously traveled in one direction at a constant distance without being reciprocated in cutting at the cutting start portion. Since the workpiece 22 is cut while suppressing the above, a cut groove having a predetermined depth is formed on the outer periphery of the workpiece 22 with a straight cut edge. For this reason, the cut groove becomes deeper in the direction perpendicular to the axial direction of the workpiece 22, and the cut direction of the wire 18 is determined to be the same direction. Therefore, even after the wire 18 shifts to reciprocating cutting, the wire 18 makes a straight cut in a direction perpendicular to the axial direction of the workpiece 22. Therefore, the cutting surface can be prevented from being inclined at the cutting start portion of the workpiece 22, the cutting accuracy of the workpiece 22 can be improved, and a highly accurate wafer can be obtained.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with a focus on differences from the first embodiment.

  In the second embodiment, as shown in FIG. 5, the method of cutting the workpiece 22 is different from that in the first embodiment. That is, when the operation of the wire saw is started, in step S11, the lowering of the work 22 by the work support mechanism 21 is started, the work 22 is brought into contact with the wire 18, and the slurry is supplied from the slurry supply mechanism 20. Is started. Subsequently, in S12, the work feed of the workpiece 22 is started, and the wire 18 continuously travels in the forward direction by a predetermined distance (for example, 5000 m) longer than the reciprocating stroke. Thereby, the cutting start part of the workpiece 22 is cut. Thereafter, in S13, the travel of the wire 18 is switched from continuous travel in the forward direction to reciprocal travel of a predetermined stroke, and the cutting of the workpiece 22 by the wire 18 is shifted to cutting by reciprocal travel.

  Accordingly, also in the second embodiment, as in the case of the first embodiment, the cutting surface can be prevented from being inclined at the cutting start portion of the work 22 and the cutting accuracy is improved. Can be made. Moreover, in this 2nd Embodiment, since it transfers to the cutting by reciprocating immediately following a one-way cutting, a cutting operation can be performed efficiently.

(Example of change)
In addition, this embodiment can also be changed and embodied as follows.
Contrary to the first and second embodiments, the present invention is embodied in a wire saw in which a work is disposed at a fixed position and a processing roller is raised and lowered.

  In the first and second embodiments, the work 22 is lowered and brought into contact with the wire 18 after the wire 18 has started to continuously run for cutting at the beginning of cutting. If it does in this way, since the workpiece | work 22 contacts the wire 18 during driving | running | working, the reluctance of the wire 18 at the time of a cutting start can further be suppressed.

(Another technical idea)
Furthermore, technical ideas other than the claims grasped by the above embodiment will be described below together with their effects.

(1) A wire that is circulated between a plurality of processing rollers by reciprocating at a predetermined stroke, and traveling forward in one direction by making the forward stroke longer than the backward stroke. In a wire saw in which the work is cut relative to the workpiece by relatively feeding the workpiece in the contact direction,
At the start of cutting, the wire is made to travel in one direction with a stroke longer than the predetermined stroke to perform cutting at the beginning of cutting, and then the wire traveling is switched to the reciprocating traveling of the predetermined stroke to continue cutting the workpiece. A wire saw provided with control means for controlling switching of the traveling direction of the wire.

  Even in such a configuration, the same effects as those of the first aspect of the invention can be exhibited.

The front view which shows the cutting method of 1st Embodiment. The perspective view which shows the principal part of a wire saw. The block diagram which shows the circuit structure of a wire saw. The flowchart which shows the cutting method of 1st Embodiment. The flowchart which shows the cutting method of 2nd Embodiment. The principal part top view which shows the conventional cutting method. The partial expanded sectional view which shows the cutting state of the workpiece | work by the conventional cutting method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 13 ... Cutting mechanism, 15, 16, 17 ... Processing roller, 18 ... Wire, 19 ... Wire travel motor, 20 ... Slurry supply mechanism, 21 ... Work support mechanism, 22 ... Workpiece, 23 ... Work lifting motor, 24 DESCRIPTION OF SYMBOLS ... Reel mechanism, 25 ... Delivery reel, 26 ... Take-up reel, 27, 28 ... Reel rotation motor, 34 ... Control circuit, 35 ... CPU which comprises control means.

Claims (5)

The wire circulated between a plurality of processing rollers is reciprocated with a predetermined stroke, and the forward stroke is made longer than the backward stroke to feed and travel in one direction as a whole. In a wire saw that is cut relative to the workpiece by feeding it in the contact direction,
At the start of cutting, the wire travels in either the forward direction or the backward direction with a stroke longer than the predetermined stroke to cut the work cutting start portion, and then the wire travels to the reciprocal travel of the predetermined stroke. A wire saw cutting method that switches and continues cutting the workpiece. 2. The cutting direction according to claim 1, wherein after the wire is continuously moved in the forward direction with a stroke longer than the predetermined stroke without contacting the workpiece, the wire is brought into contact with the workpiece by the same distance before starting cutting. The cutting is started at the cutting start portion, then the wire is moved in the forward direction by the same distance while being separated from the workpiece, and then the cutting is performed by the reciprocating traveling of the wire. Cutting method in wire saw. 2. The cutting method for a wire saw according to claim 1, wherein the wire is caused to travel in the forward direction, the cutting at the cutting start portion is executed, and then the cutting is performed by the reciprocating traveling of the wire. The cutting method for a wire saw according to any one of claims 1 to 3, wherein in cutting the cutting start portion, at least a depth corresponding to the diameter of the wire is cut to 5 mm or less. The cutting method for a wire saw according to any one of claims 1 to 4, wherein a traveling distance in one direction of the wire in cutting of the cutting start portion is in a range of 500 m to 5000 m.

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