Wire saw bobbin, wire saw equipped therewith, and method for controlling the wire saw

Abstract

In wire saw bobbins, this prevents wire breakage caused by twisting due to friction with the end face of the bobbin's flange. [Solution] The wire saw bobbin 2 comprises a bobbin body 2a with a circular cross-section having a constant outer diameter capable of winding multiple layers of wire 3 used in the wire saw 1, and a pair of flange portions 2b formed at both axial ends of the bobbin body 2a, with a larger outer diameter than the bobbin body 2a. The pair of flange portions 2b of the wire saw bobbin 2 are formed to have a taper angle A that moves away from each other in the axial direction outward.

Description

Technical Field

[0001] The present invention relates to a bobbin for a wire saw, a wire saw including the same, and a method for controlling the wire saw.

Background Art

[0002] Conventionally, for precision cutting of semiconductor wafers and the like, a wire in which diamond powder is solidified with a binder or the like on a piano wire has been used. This wire is wound around one wire saw bobbin having flange portions at both ends, and while the wire is fed out and wound around the other wire saw bobbin, the material is cut in a processing chamber.

[0003] For example, as in Patent Document 1, it is known that the central portion of the body of the bobbin is tightened by the wire and deformed in a direction of diameter reduction, and the pair of flange portions at both ends of the body are deformed so as to approach each other.

[0004] On the other hand, if the thickness of the body is increased to prevent such inclination and make it difficult to deform, the wire layer is compressed by the tightening force when the wire is wound in multiple layers or when the multi-layer wound wire is fed out, and it is also known that the pair of flange portions incline so as to separate from each other.

[0005] For this reason, for example, as in Patent Document 2, there is known a device that prevents the flange portion from inclining even when a large tension is applied by the wire.

[0006] Further, as in Patent Document 3, there is known a wire saw having a wire for processing a workpiece, a plurality of wire guides for circulating the wire, a bobbin on one side for feeding out the wire to the wire guide, and a bobbin on the other side for winding up the wire from the wire guide.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

[0008] Incidentally, the wire wound on the feed-side bobbin of the wire saw is fed to the wire guide in the processing chamber, and the wire used for processing is wound onto the winding-side bobbin. During the unwinding and winding of these bobbins, the wire rubs against the end face of the flange portion of the bobbin, causing twisting of the wire and creating a risk of wire breakage.

[0009] This invention has been made in view of the above, and its purpose is to prevent the wire from breaking due to twisting caused by rubbing against the end face of the flange portion of the bobbin. [Means for solving the problem]

[0010] To achieve the above objective, in this invention, a pair of flange portions are intentionally formed to have a taper angle that moves away from each other in the axial outward direction.

[0011] Specifically, the wire saw bobbin of the first invention is A bobbin body with a circular cross-section and a constant outer diameter, capable of winding multiple layers of wire used in a wire saw, The bobbin body comprises a pair of flange portions formed at both axial ends of the bobbin body, the flange portions having an outer diameter larger than the outer diameter of the bobbin body. The pair of flange portions are formed such that, when the wire is not being wound, they are tapered away from each other in the axial direction outward.

[0012] According to the above configuration, since the pair of flange portions are intentionally formed in advance to have a taper angle that moves away from each other in the axial direction outward when the wire is not wound around them, even if the pair of flange portions deform to move closer together due to the tension of the wire, it is possible to prevent the wire from unintentionally coming into contact with the flange portions by, for example, setting the taper angle in consideration of the amount of deformation.

[0013] The wire saw of the second invention is, The first invention of a wire saw bobbin, A bobbin motor for rotating the wire saw bobbin, A slide pulley on which the wire unwound from or wound onto the bobbin body is attached, A traverser that slides the slide pulley in the axial direction of the bobbin body by a predetermined traverse width, The system includes a control unit that changes the traverse width in accordance with the taper angle of the flange portion based on the rotation speed of the bobbin motor and the outer diameter of the wire winding.

[0014] Furthermore, in the wire saw control method of the third invention, The first invention of a wire saw bobbin, A bobbin motor for rotating the wire saw bobbin, A pulley over which the wire unwound from the bobbin body is placed, Prepare a wire saw equipped with a traverser that moves the pulley in the axial direction of the bobbin body by a predetermined traverse width, The wire is wound onto the bobbin for the wire saw, The traverse width is changed according to the taper angle of the flange portion based on the rotation speed of the bobbin motor and the outer diameter of the wire winding, and the workpiece is cut by the wire while the wire is being fed out.

[0015] According to these configurations, since a taper angle is given to a pair of flange portions in advance so that they are separated from each other, the winding width of the wire changes according to the amount of wire wound, and by changing the traverse width according to the taper angle of the flange portion from the rotation speed of the bobbin motor and the outer diameter of the wire wound, the slide pulley can be moved to an optimal position, and the risk of wire breakage due to wire twist or the like can be more effectively prevented.

Advantages of the Invention

[0016] As described above, according to the present invention, it is possible to prevent the wire from being broken by rubbing against the end face of the flange portion of the bobbin and being twisted.

Brief Description of the Drawings

[0017] [Figure 1A] It is a front view showing a main part of a wire saw having a bobbin for a wire saw according to an embodiment of the present invention. [Figure 1B] It is a side view showing a main part of a wire saw having a bobbin for a wire saw according to an embodiment of the present invention. [Figure 2A] It is a front view showing an enlarged view of a bobbin for a wire saw and its surroundings. [Figure 2B] It is a front view showing an enlarged view of a bobbin for a wire saw and its surroundings considering flange deformation. [Figure 3] It is a control block diagram according to an embodiment of the present invention. [Figure 4] It is a control flowchart according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0019] Figures 1A and 1B show a wire saw 1 having a wire saw bobbin 2 according to an embodiment of the present invention. Although not shown in detail, this wire saw 1 includes a wire 3 for processing a workpiece W, a plurality of wire guides for circulating the wire 3, a wire saw bobbin 2 on one side for feeding the wire 3 to the wire guides, and a wire saw bobbin 2 on the other side for winding the wire 3 from the wire guides.

[0020] Each wire saw bobbin 2 has a bobbin motor 4 and is configured to rotate in the unwinding direction and winding direction at a predetermined rotational speed.

[0021] As shown in an enlarged view in Figure 2A, the wire saw bobbin 2 comprises a bobbin body 2a with a circular cross-section having a constant outer diameter D, capable of winding multiple layers of wire 3 used in the wire saw 1, and a pair of flange portions 2b formed at both axial ends of the bobbin body 2a, with an outer diameter larger than the outer diameter D of the bobbin body 2a.

[0022] As shown in Figures 1A to 2B, the wire saw 1 is equipped with slide pulleys 5 on which wire 3, which is unwound from one bobbin body 2a or wound onto the other bobbin body 2a, is attached. In these figures, the wire saw bobbin 2 and slide pulley 5 on one side are shown, but a wire guide, the slide pulley 5 on the other side, and the wire saw bobbin 2 are provided at the end of the wire 3.

[0023] The wire saw 1 is further equipped with a traverser 6 that slides the slide pulley 5 in the axial direction of the bobbin body 2a by a predetermined traverse width (Tmin to Tmax). The traverser 6 is rotated by a traverser motor 7, and is configured to change the position of the slide pulley 5 by a propulsion means such as a ball screw.

[0024] As shown in Figure 2B, deformation of the pair of flange portions 2b can particularly affect the maximum traverse width Tmax.

[0025] The wire saw 1 is further equipped with a controller 10, which acts as a control unit that changes the traverse width according to the taper angle A of the flange portion 2b based on the rotation speed of the bobbin motor 4 and the outer diameter of the wire 3. The controller consists of a microcomputer or the like, and has a processor and memory, and is configured to control the entire wire saw 1 using a program stored in the memory.

[0026] One feature of the present invention is that the pair of flange portions 2b are intentionally formed to have a taper angle A that moves away from each other in the axial outward direction when the wire 3 is not being wound around them.

[0027] The control block of the wire saw 1 will be explained using Figure 3. The controller 10's memory stores a traverser end position correction calculation program.

[0028] The controller 10 sends a signal to the bobbin motor amplifier 4a to control the rotational speed of the bobbin shaft of the bobbin motor (also called the bobbin motor rotational speed).

[0029] The bobbin motor amplifier 4a controls the rotation of the bobbin motor 4 by issuing a bobbin motor speed command in accordance with the received signal.

[0030] The controller 10 also issues commands to the traverser amplifier 7a using a traverser end position correction calculation program, and the traverser amplifier 7a issues traverser speed commands and traverser position commands to control the rotation speed and rotation direction of the traverser motor 7.

[0031] -Control method for wire saw bobbins- Next, the control method for the wire saw bobbin 2 according to this embodiment will be explained with reference to Figure 4.

[0032] First, prepare the wire saw 1 as described above. On one wire saw bobbin 2, wind a predetermined number of wires 3 in advance. Although not shown in detail in the diagram, the end of the wire 3 unwound from this wire saw bobbin 2 is connected to the other wire saw bobbin 2 through a wire guide.

[0033] Then, in step S01, the operation begins.

[0034] In step S02, it is determined whether or not there is a change in the rotational speed of the bobbin motor 4. If there is a change in rotational speed, proceed to step S03; otherwise, return to step S02.

[0035] In step S03, the traverser operating end correction value is calculated from the change in the rotational speed of the bobbin motor 4.

[0036] Specifically, the inputs are the wire winding outer diameter D mm of the reference bobbin body 2a, the end position X mm of the previous traverser 6, the taper angle A deg, the rotational speed r rpm of the previous bobbin motor 4, the change in rotational speed Δr rpm of the bobbin motor 4, and the deformation coefficient B of the flange portion 2b, and the output is the corrected end position X' mm of the traverser 6. Diameter change ΔD = D × r / (r + Δr) - D Correction amount at the traverser end: ΔX = (ΔD / 2) × Tan(A) × B This is the result.

[0037] In step S04, the end position X of the traverser 6 is rewritten using the value of ΔX.

[0038] In step S05, it is determined whether the control has finished. If it has finished, the process ends in step S06. If it has not finished, the process returns to step S02 and the control is repeated.

[0039] In this way, the traverse width is changed according to the taper angle A of the flange portion 2b based on the rotation speed of the bobbin motor 4 of the wire saw bobbin 2 on the other side and the winding outer diameter of the wire 3, and the workpiece is cut by the wire 3 while either feeding out or winding up the wire 3.

[0040] In this embodiment, a taper angle A is predetermined on the pair of flange portions 2b so that they are separated from each other. As the winding width of the wire 3 changes according to the amount of wire 3 wound, the control unit changes the traverse width in accordance with the taper angle A of the flange portion 2b based on the rotation speed of the bobbin motor 4 and the outer diameter of the winding of the wire 3. This moves the slide pulley 5 to the optimal position, more effectively preventing the risk of wire breakage due to twisting or other reasons.

[0041] As shown in Figure 2B, the distance between the pair of flange portions 2b may increase or decrease due to the tension of the wire 3, etc. However, in this embodiment, the controller 10 can calculate the correction amount ΔX of the traverser end in real time.

[0042] Thus, in this embodiment, the pair of flange portions 2b are intentionally formed in advance to have a taper angle A that moves away from each other in the axial direction outward when the wire 3 is not wound around them. Therefore, even if the pair of flange portions 2b deform to move closer together due to the tension of the wire 3, by setting the taper angle A in consideration of the amount of deformation, for example, it is possible to prevent the wire 3 from unintentionally coming into contact with the flange portions 2b.

[0043] Therefore, according to the wire saw bobbin 2 of this embodiment, it is possible to prevent the wire 3 from breaking due to twisting caused by rubbing against the end face of the flange portion 2b of the bobbin.

[0044] (Other embodiments) The present invention may also have the following configuration in the above embodiment.

[0045] In other words, in the above embodiment, the controller 10 was described as an example of a control unit. However, the control unit controls the "wire saw 1" and can be physically configured in any way as long as it has a CPU (processor) and memory. For example, the control unit may utilize software (programs), such as a microcomputer or a programmable logic controller (PLC). Alternatively, the control unit may be realized by combining hardware (circuit components).

[0046] The embodiments described above are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of Symbols]

[0047] 1 Wire saw 2. Bobbins for wire saws 2a Bobbin body 2b Flange section 3 wires 4. Motor for bobbins 4a Motor amplifier for bobbins 5 Slide pulley 6 Traverser 7. Traverser motor 7a Amplifier for traverser 10 Controllers

Claims

1. A bobbin body with a circular cross-section and a constant outer diameter, capable of winding multiple layers of wire used in a wire saw, The bobbin body comprises a pair of flange portions formed at both axial ends of the bobbin body, the flange portions having an outer diameter larger than the outer diameter of the bobbin body. The pair of flange portions are formed to have a tapered angle that moves away from each other in the axial direction outward when the wire is not being wound. A bobbin for wire saws characterized by the following features.

2. A wire saw bobbin according to claim 1, A bobbin motor for rotating the wire saw bobbin, A slide pulley on which the wire unwound from or wound onto the bobbin body is attached, A traverser that slides the slide pulley in the axial direction of the bobbin body by a predetermined traverse width, The system includes a control unit that changes the traverse width in accordance with the taper angle of the flange portion based on the rotation speed of the bobbin motor and the outer diameter of the wire winding. A wire saw characterized by the following features.

3. A wire saw bobbin according to claim 1, A bobbin motor for rotating the wire saw bobbin, A pulley over which the wire unwound from the bobbin body is placed, Prepare a wire saw equipped with a traverser that moves the pulley in the axial direction of the bobbin body by a predetermined traverse width, The wire is wound onto the aforementioned wire saw bobbin, The traverse width is changed according to the taper angle of the flange portion based on the rotation speed of the bobbin motor and the outer diameter of the wire winding, and the workpiece is cut by the wire while the wire is being fed out. A wire saw control method characterized by the following.

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