SAME

FIELD OF THE INVENTION

[0001] Aspects of the present invention relate to a wire saw device and a method for operating such a wire saw device. More particularly, aspects of the invention relate to a wire saw device for cutting or sawing hard materials such as blocks of silicon or quartz, e.g., for cutting silicon wafers, for a squarer, for a cropper or the like.

BACKGROUND OF THE INVENTION

[0002] Wire saw devices exist for cutting blocks or bricks, thin slices, e.g., semiconductor wafers, from a piece of hard material such as silicon. In such devices a stretched wire is fed from a spool and is both guided and tensioned by wire guide cylinders. The wire that is used for sawing is generally provided with an abrasive material. As one option, the abrasive material can be provided as a slurry. This may be done shortly before the wire touches the material to be cut. Thereby, the abrasive is carried to the cutting position by the wire for cutting the material. As another option, the abrasive can be provided on the wire with a coating. For example, diamond particles can be provided on a metal wire with a coating, wherein the diamond particles are imbedded in the coating of the wire. Thereby, the abrasive is firmly connected with the wire.

[0003] Generally, there is a tendency to use thinner wires in order to reduce the thickness of the cut and, thereby, to decrease the material wasted. There is also a desire to use diamond wires. These thinner wires and diamond wires are generally more susceptible to damage, and under high strain the wires may break more easily. Further, there is a desire to increase the cutting speed for improving the throughput of wire saw devices. The maximum speed for moving the piece through the web, and also the maximum effective cutting area within a given amount of time, is limited by several factors including wire speed, hardness of the material to be sawed, disturbing influences, desired precision, and the like. When the speed is increased, the strain on the wire is generally increased as well. Hence, the above-mentioned problems of avoiding damage or breakage of the wire are even more critical at higher sawing speeds.

SUMMARY

[0004] In view of the above, wire management units according to independent claims 1 and 2, a wire saw device according to claim 20, and methods according to independent claims 22 and 23 are provided. Further advantages, features, aspects and details are apparent from the dependent claims, the description and drawings.

[0005] According to an embodiment, a wire management unit adapted for a wire saw device having a wire forming a wire web is provided. The wire management unit has a main frame portion and a wire handling section, the wire handling section including: a spool shaft adapted for carrying a spool providing the wire towards the wire web; a first pulley adapted for receiving the wire from the spool and for redirecting the wire, the first pulley being rotatably mounted to a pulley carrying unit for rotation around a first pulley axis, the pulley carrying unit being longitudinally movable along a pulley motion track; and a second pulley adapted for receiving the wire from the first pulley and for redirecting the wire, wherein the second pulley is rotatably mounted to the main frame portion for rotation around a second pulley axis, wherein the first pulley and the second pulley are arranged such that, during operation, the wire is redirected by the first pulley by a first redirection angle of not more than 120°, and that the wire is redirected by the second pulley by a second redirection angle of not less than 60°. According to a further embodiment, the first pulley and the second pulley are arranged such that during operation the wire is redirected by the first pulley by a first redirection angle, and that the wire is redirected by the second pulley by a second redirection angle being larger than the first redirection angle.

[0006] According to a further embodiment, a wire saw device having a wire forming a wire web is provided. The wire saw device includes a wire management unit. The wire management unit has a main frame portion and a wire handling section. The main frame portion is rigidly connected to a chassis of the wire saw device. The wire handling section includes: a spool shaft adapted for carrying a spool providing the wire towards the wire web; a first pulley adapted for receiving the wire from the spool and for redirecting the wire, the first pulley being rotatably mounted to a pulley carrying unit for rotation around a first pulley axis, the pulley carrying unit being longitudinally movable along a pulley motion track; and a second pulley adapted for receiving the wire from the first pulley and for redirecting the wire, wherein the second pulley is rotatably mounted to the main frame portion for rotation around a second pulley axis, wherein the first pulley and the second pulley are arranged such that, during operation, the wire is redirected by the first pulley by a first redirection angle of not more than 120°, and that the wire is redirected by the second pulley by a second redirection angle of not less than 60°. According to a further embodiment, the first pulley and the second pulley are arranged such that during operation the wire is redirected by the first pulley by a first redirection angle, and that the wire is redirected by the second pulley by a second redirection angle being larger than the first redirection angle.

[0007] According to a further embodiment, a method of operating a wire saw device having a main frame portion, the method including providing wire from a spool; moving a pulley carrying unit longitudinally along a pulley motion track; receiving the wire from the spool by a first pulley and redirecting the wire by the first pulley, the first pulley being rotatably mounted to the pulley carrying unit for rotation around a first pulley axis; receiving the wire from the first pulley by a second pulley and redirecting the wire by the second pulley, the second pulley being rotatably mounted to the main frame portion for rotation around a second pulley axis, whereby the first pulley redirects the wire by a first redirection angle of not more than 120°, and the second pulley redirects the wire by a second redirection angle of not less than 60°. According to a further embodiment, the second pulley receives a greater load due to wire tension of the wire than the first pulley.

[0008] Embodiments are also directed at apparatuses for carrying out the disclosed methods and including apparatus parts for performing each described method step. These method steps may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments according to the invention are also directed at methods by which the described apparatus operates. It includes method steps for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features of aspects of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the invention and are described in the following:

Fig. 1 shows a schematic view of a portion of a wire management unit showing wire being unwound from a spool over a roller;

Fig. 2 shows a schematic side view of a portion of a wire management unit according to embodiments described herein;

Fig. 3 shows a schematic side view of a portion of a wire management unit according to variations of the embodiments of Fig. 2;

Fig. 4 shows a schematic front view of a portion of a wire management unit according to further embodiments;

Fig. 5 shows a perspective view of a portion of a wire management unit according to the embodiments of Fig. 2;

Fig. 6 shows a perspective view of a wire management unit including the portion shown in previous Figures;

Fig. 7 shows a schematic view from above of a portion of a wire management unit according to further embodiments described herein;

Fig. 8 shows a schematic top view of a wire saw device including a wire management unit according to further embodiments described herein;

Fig. 9 shows a spray nozzle being part of a wire saw device according to further embodiments described herein; and

Fig. 10 shows a coolant tank being part of a wire saw device according to further embodiments described herein.

DETAILED DESCRIPTION

[0010] Reference will now be made in detail to the various embodiments of the invention, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of aspects of the invention and is not meant as a limitation of the invention. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0011] Furthermore, in the following description, a wire management unit will be understood as a device handling the supply of wire to a working area of a wire saw device, such as a cropper, a squarer, or a wafer-cutting wire saw. Typically, the wire saw includes a wire guide for transporting and guiding the wire in a wire moving direction while the wire management unit provides control of the wire tension. Furthermore, the wire provided by the wire management unit forms a wire web as described above. In the following, a wire web will be considered as the web formed by a single wire management unit. It should be understood that a wire web may contain more than one working area which is defined as an area in which a sawing process is performed.

[0012] Typically, embodiments of wire guides described herein are adapted or configured for wire saw devices, they can be used in wire saw devices and/or can be a part of a wire saw device. Besides other aspects that can be used for adapting or configuring any pulley or other part described herein for a wire saw device, such a pulley can have a groove structure which is made to guide a wire with a thickness of 400 μιη or below, or a thickness of any of the other diameters mentioned above. Thereby, it has to be noted that the groove structure is designed specially for the wire diameter and the cutting process in order to allow for a high precision cutting, e.g. with a precision of 250 μιη or below, or even of 50 μιη or below.

[0013] As shown in FIG. 1, within a wire saw device a wire 10 is provided from a spool 12. During sawing, the wire 10 is unwound from the spool 12. Thereby, the spool rotates around its axis 12a. FIG. 1 shows the wire 10 being carried on a wire carrying area 13a of the spool. Within the wire saw device , the wire 10 is guided from the spool 12 over a roller 11 to pulleys 20, 30, which rotate around respective pulley axes, e.g., 32. The wire 10 is then guided to a cutting area, in which a wire web is formed. Thereby, for example, the wire 10 is transported through a main frame portion 100' of a main frame of the wire saw device . Herein, a main frame is understood to be a part of the apparatus that is rigidly connected to the chassis of the wire saw device during operation. Hence, when parts of the wire management unit such as pulleys are mounted on the main frame portion, this mounting is generally very stable. [0014] During a cutting process by means of wire saw, the machine unwinds new wire 10 from the spool 12. During unwinding of the wire 10 from the spool 12, the position at which the wire leaves the wire carrying area 13a moves along the axis 12a, i.e., moves in direction parallel to the axis 12a. As the spool unwinds, the wire moves alternately from one side of the spool to the other (flange to flange). This is indicated by the wire 10, 10' being unwound from the spool 12 at different positions, as indicated by the dotted lines showing a wire 10' at a different position than the wire 10.

[0015] For modern wire saw devices like croppers, squarers, or wire saws, there is the desire to cut the hard material such as semiconductor material, for example silicon, quartz, or the like at high speed. The wire speed, that is the speed of the wire moving through the wire saw device, the wire management unit and the material to be sawed, respectively, can be, for example, 10 m/s or higher. Typically, the wire speed can be in a range of 15 to 20 m/s. However, higher wire speeds of 25 m/s or 30 m/s can also be desirable and could be realized under certain conditions.

[0016] For unwinding the wire at the desired wire speed, the spool rotates with a rotation speed of up to several thousands rotations per minute. For example, 1000 to 2000 rpm can be provided for unwinding the wire. Accordingly, as indicated in FIG. 1, the different positions, at which the wire 10 leaves the spool 12, also vary at considerable speed and the angle under which the wire 10 enters the pulley 20 varies correspondingly. The angle between the wire at the spool 12 and the entrance of the fixed pulley groove of the pulley 20 thus changes periodically. This variation generates vibration in the wire as it slides from one side of the pulley groove to the other. This variation can eventually even result in the wire climbing up the side walls 23 of the groove. These vibrations are detrimental to the process as they create a high risk of wire breakage, e.g., due to a spike in tension within the wire as the wire accommodates the vibrations amplitudes and a movement up and down on the pulley groove side walls 23. Further, this may be particularly relevant as there is a desire for thinner wire diameters and for diamond-coated wires, because in these cases the wire may also break even more easily. Further, the varying wire position on the spool 12 and, in particular, the varying angles under which the wire 10 enters the pulley 20 may result in oscillations in the wire saw device, which may deteriorate the cutting precision.

[0017] To this purpose, the fixed pulley 20 may be replaced by a movable pulley that is longitudinally movable in a direction parallel to the spool axis 12a. The movable pulley can be equipped with a tracking system allowing it to follow the position of the wire moving from one side of the spool to the other, so that the wire always enters the pulley tangentially. Such a pulley is described, e.g., in the European patent application No. EP 09153051.9, which is herewith incorporated herein by reference, see in particular the description of the tracking system on Fig. 3A and Fig. 3B and the corresponding description thereof in European patent application No. EP 09153051.9. However, in view of the sometimes considerable tension of the wire, it is difficult to support the movable pulley sufficiently firmly so that the movable pulley can bear the high wire tension. If the movable pulley is not sufficiently firmly supported, unwanted deformations and vibrations of the pulley support, the movable pulley, and hence of the wire may occur. Such vibrations may, again, result in the unwanted oscillations in the wire and in some cases may result even in wire breakage.

[0018] Accordingly, it is desired to improve the wire management unit such that the above difficulties are reduced. According to one embodiment, which is described with respect to FIG. 2, a wire saw device 1 is provided. Within the wire saw device, there is a wire management unit, some components of which are shown in FIG. 2. According to different embodiments, a wire saw device 1 can be a cropper, a squarer, a wire saw or a multiple wire saw. Thereby, a cropper is to be understood as a device, which can be used to saw end pieces from bricks or blocks, which have been separated into bricks in a squarer. A squarer is a wire saw that generally saws the silicon ingot into squares of the desired size such that a wire saw or a multiple wire saw can saw wafers from the bricks in a wafering process. The wire management unit herein is particularly useful for the wire saw device being a squarer, but not limited to a squarer.

[0019] The wire management unit of FIG. 2 includes a spool 212 having a spool axis 212a. The spool is carried by a spool shaft 210. The spool shaft 210 is rotatably mounted to the main frame portion 100 for rotation around a spool axis 212a. Thereby, the spool shaft 210 rotates the spool about the spool axis 212a. The spool shaft rotation may be driven by a spool motor. In contrast, the pulleys to be described below are generally freely rotatable. On the spool 212, wire 10 to be provided towards the wire web is carried in a wire carrying area 213a of the spool 212. The wire carrying area 213a has a wire carrying length along the direction of the spool axis 212a. During unwinding of the wire 10 from the spool 212, the wire is provided towards the wire web of the wire saw.

[0020] A first pulley 220 is shown in FIG. 2. Here and in general, a pulley has a groove adapted for guiding the wire. Further, a pulley generally can have a wire guiding position for guiding one wire in the pulley, i.e., in the pulley groove. The first pulley 220 is adapted for receiving the wire 10 from the spool 212, in particular directly from the spool 212, and for then redirecting the wire. The first pulley is rotatably mounted to a pulley carrying unit 224, so that the first pulley 220 rotates around the first pulley axis 222. The pulley carrying unit 224, in turn, is connected to the wire saw device, more specifically to a main frame portion 100 of the wire saw device 1, so that the pulley carrying unit 224 is longitudinally movable along a pulley motion track, i.e., the pulley motion track is defined as the region along the pulley carrying unit is movable. Thereby, also a first pulley motion track for the first pulley is defined, i.e., a track along which the first pulley 220 is longitudinally movable. Further, as a general aspect, the first pulley motion track may have a length of at least 90% of the length of a wire carrying area 213a of the spool 212. Here, the wire carrying area 213a is the lengthwise section of the spool 212 from which the wire may emerge from the spool, i.e., generally the length from flange to flange of the spool. As a further general aspect, the pulley motion track may extend over the length of the wire carrying area 213a, from flange to flange.

[0021] The main frame portion 100 is rigidly connected or rigidly connectable to the wire saw device chassis. Thereby, the main frame portion 100 is very robust and, e.g., a load on the main frame portion can be absorbed by the chassis. The main frame portion 100 may be made of one piece or consist of multiple pieces such as the pieces 110 and 112 shown in Fig. 2. Here, the multiple pieces 110, 112 are rigidly connected to each other, e.g., by means of screws or some other connectors. Independently of the shown embodiment, the main frame portion 100, as a whole, is rigidly connected to the chassis of the wire saw device during operation.

[0022] The pulley motion track of pulley 220 is essentially parallel to the spool axis 212a. According to embodiments which can be combined with any other embodiment described herein, other directions of movement might be superimposed to the above described movement. For example, a curved track and/or an inclined track with respect to the spool axis 212a may be provided.

[0023] In Fig. 2, the pulley carrying unit 224 is shown as a beam. In other embodiments, which can be combined with any other embodiment described herein, it may be provided as a rod or as another support carrying the pulley 220 such that it can rotate around its axis 222.

[0024] The first pulley axis 222 is oriented at an angle of essentially 90° with respect to the spool axis 212a. Herein, the angle is defined as a spatial angle, i.e., the angle of the axes in the plane spanned by the axes (if necessary, after a parallel shift of one of the axes so that the axes cross and hence span a plane). The angle is defined as an absolute value, i.e., is always positive.

[0025] According to embodiments which are described herein, a pulley moving device 228 is provided. The pulley moving device 228 is indicated by an arrow in FIG. 2, and is adapted to cause the pulley carrying unit 224 to move along the pulley motion track in a bi-directional mode. The pulley moving device 228 is adapted to move the pulley 220 and the wire position detection device along the motion track (here: parallel to the axis 212a of the spool) in order to position the pulley at the desired position over the spool 212. The pulley moving device 228 can be, e.g., a linear actuator such as lineal motor, a pneumatic cylinder, a motor with a worm drive, a rack-pinion-gear or the like, such that the pulley moving device is capable of moving the pulley at least in a linear direction along the pulley motion track. Thereby, the pulley can be moved by moving the pulley carrying unit 224 relative to the main frame portion 100 of the wire saw device 1.

[0026] According to further embodiments, which can be combined with other embodiments described herein, a wire position detection device 226 can be provided. The wire position detection device detects the wire position along the direction of the motion path (here: along the spool axis 212a), more particularly it detects at which wire position the wire traverses a detection region of the wire position detection device 226. Thereby, the position at which the wire 213a leaves the spool 212 or the wire carrying area 213a can be obtained (if necessary by triangulation).

[0027] The wire position detection device 226 is connected to the pulley moving device 228. Thereby, for example, a signal receiving unit, a controller, a computer for calculating the correct pulley position, or the like can be provided within the connection between the wire position detection device 226 and the pulley moving device 228. In a particular embodiment, a controller is operatively connected to the wire position detection device 226 for receiving the detected wire position. The controller determines a target position, and transmits a moving command to the first pulley moving device 228, such as to cause the first pulley moving device to move the first pulley to the target position. In particular, the target position may be the position which corresponds to the position at which the wire 213a leaves the spool. With this target position, the wire leaves the spool at a right angle with respect to the pulley axis 212a, as shown in Fig. 2. The first pulley moving device 228, the wire position detection device 226, and the first pulley position controller may be collectively referred to as a the first pulley wire tracking system. Generally, a first pulley wire tracking system may be provided for allowing actuation of the first pulley moving device 228 in response to a detected wire position.

[0028] Further, as a general aspect the pulley motion track of the first pulley 220 is arranged such that for any position at which the wire 10 exits the wire carrying area 213a of coil 212, there is at least one position of the first pulley 220 on the pulley motion track such that the wire is entering the first pulley 220 essentially tangentially. Further, generally, the first pulley 220 (and any other pulleys if present in the embodiment, such as the second pulley 230 described below) may be arranged such that for any position at which the wire 10 exits the wire carrying area 213a of coil 212, there is at least one position of the first pulley 220 on the pulley motion track such that the wire is exiting and entering any one of the coil and the pulleys essentially tangentially. This arrangement allows for a twist-free wire. Herein, "twist- free" refers to the wire entering and exiting the coil and the pulleys of the wire management unit essentially tangentially. As a counter-example, the wire shown in Fig. 1, which enters and exits the pulley 20 non-tangentially, is twisted. Thus, the controller may be programmed to actuate, for any position of the wire 10 exiting the wire carrying area 213a, the pulley moving device 228 such that the wire is entering the first pulley 220 essentially tangentially, and in particular such that the wire is essentially twist-free.

[0029] Continuing the description of embodiments with reference to Fig. 2, the wire management unit of Fig. 2 has a second pulley 230, which is adapted for receiving the wire from the first pulley 220, in particular directly from the first pulley, and for redirecting the wire. The second pulley 230 is rotatably mounted to the main frame portion 100 for rotation around a second pulley axis 232. Generally, within the wire management unit, further pulleys can be provided as well.

[0030] The wire is redirected by the first pulley 220 by a first redirection angle of 90°, and by the second pulley 230 by a second redirection angle of 180°. Due to the large second redirection angle, a main portion of the wire tension, especially in the case of tension peaks, is absorbed by the second pulley which is firmly supported by the main frame portion 100. Due to the firm support by the wire main frame portion 100, the second pulley 230 can bear the tension more easily and stably than the moveable first pulley 220. Thereby, unwanted deformations and vibrations of the movable pulley 220 and, hence, of the wire are reduced. By consequence, the oscillations of the wire itself, of components of the wire management unit, or of other components of the wire saw device can be reduced as well. Further, the risk of wire breakage is reduced. Thereby, a higher wire speed and hence a higher wire throughput can be achieved.

[0031] Generally, wire tension can be absorbed to some degree by the firmly attached second pulley 230 if the wire is redirected by the first pulley by a first redirection angle of not more than 120°, and if the wire is redirected by the second pulley by a second redirection angle of not less than 60°. In the example of Fig. 2, the redirection angles are independent of the location of the first pulley 220 on the first motion track, but more generally the above condition should be met for at least one location of the first pulley 220 on the first motion track. In some embodiments, which can be combined with any other embodiments described herein, the above condition is even met for any location of the first pulley on the first motion track. In some embodiments, the first redirection angle is 100° or less, or even 90° or less. Further, in some embodiments, the second redirection angle is not less than 90°, not less than 120°, or even 180°. Here, the redirection angle is defined as the integral of the deflection angles by which the wire is deflected. Hence, e.g., a quarter turn leads to a deflection angle of 90°, and a three quarter turn leads to a deflection angle of 270°. The deflection angle is taken as an absolute value and hence is always positive, regardless of the deflection direction.

[0032] Also, an alternative and generally useful configuration can be expressed as follows: In a configuration, the second redirection angle is larger than the first redirection angle. In this configuration, the load received by the second pulley due to wire tension of the wire may be greater than the load received by the first pulley. Again, this may help avoiding an excessive load on the moveable first pulley. A further alternative and generally useful configuration can be expressed as follows: In a configuration, the redirection angles are chosen such that the second pulley 230 receives a greater load due to wire tension of the wire 10 than the first pulley 220.

[0033] In Fig. 2, the first and second redirection angles are directed in opposite winding directions to one another. This allows for a particularly compact arrangement and also allows for a particularly efficient wire tension absorption by the second pulley. Further, the first pulley axis 222 and the second pulley axis 232 are essentially parallel to each other. More generally, in embodiments the first pulley axis (222) and the second pulley axis (232) may have an angle of less than 90° with respect to each other. Further, in Fig. 2, the wire 10 is deflected by the first pulley 220 in a direction away from a wall element 110 of the main frame 100. Then, the wire 10 is deflected by the second pulley 230 in a direction towards the wall element 110 of the main frame 100. [0034] Further, the pulley motion track in Fig. 2 is parallel to the wire section of the wire 10 between the first pulley 220 and the second pulley 230. Thereby, for any position of the first pulley 220, the wire between the first and the second pulley extends in the direction of (i.e., parallel to) the pulley motion track. This means that the orientation of the wire 10 is not influenced by the position of the first pulley 220 on the pulley motion track. Further, for any position of the first pulley, the first pulley and second pulley are arranged to each other such that the wire exits from the first pulley tangentially, and is fed to the second pulley tangentially, or twist-free.

[0035] Further, the spool shaft might be particularly useful if thin wires or wires with a coating, e.g., a diamond coating, are used. Especially, the spool shaft is adapted for a squarer. Accordingly, in embodiments, which can be combined with other embodiments described herein, the wire handling sections and wire saw devices described herein are adapted for thin wires having a diameter below about 400 μιη, such as diameters between about 200 μιη and about 400 μιη, more particularly between about 200 μιη and about 300 μιη. However, in other cases, embodiments may also have a wire diameter as low as, for example, 100 μιη or even 80 μιη. Further, the wire handling sections and wire saw devices described herein are adapted for coated wires, for example, a wire having a nickel coating with diamond particles embedded therein. Such wires may typically have a diameter of about 300 μιη to about 400 μιη, e.g., 310 μιη to 340 μιη. Since mounting and unmounting of diamond wire may be necessary especially often, e.g., for bidirectional sawing or due to generally short wire length, the spool shaft disclosed herein is particularly useful for diamond wire. For those wires a twisting of the wire might increase the risk of breaking of the wire or of damaging the coating, so that twist- free operation, as shown in Fig. 2, is advantageous. By using diamond wire, the throughput may be increased by a factor of 2 or even more. In the case of a squarer, throughput rates of 100MW or even more can be achieved in this manner. When a diamond wire is used, further parts of the wire saw may be adapted to the diamond wire. For example, mechanical parts, electrical parts and / or software may be adapted to the use of diamond wire.

[0036] In the following, yet further embodiments are described, whose elements can be combined with any elements of other embodiments described herein. Within the following description, only those elements will be described which deviate from those of previous or other embodiments described herein. It is to be understood that components, aspects and details described with respect to other embodiments can as well be applied to those embodiments which do not describe all components, aspects or details. [0037] Fig. 3 shows a further embodiment in which the first pulley 220 is shown in a different position on the pulley motion track (farther away from the main frame portion 100) than in Fig. 2. Further, Fig. 3 illustrates some variations with respect to the embodiments described in relation to Fig. 2. All these variations can be included independently from each other in the embodiment of Fig. 2. As a first variation illustrated in Fig. 3, a recess 116 is provided in the main frame portion 100. The recess is dimensioned and arranged for at least partially accommodating the first pulley 220. This recess allows the first pulley 220 and, hence, the spool 212 to be arranged closer to the main frame portion 100 while still allowing the first pulley 220 motion track to cover most or all of the wire carrying area 213a.

[0038] As a further variation illustrated in Fig. 3, the main frame portion 100 of Fig. 3 is integrally formed as one piece, instead of being included of several parts as shown in Fig. 2. The main frame portion 100 may even be integrally formed with the main frame as one and the same piece.

[0039] As a further variation illustrated in Fig. 3, a third pulley 240 adapted for receiving the wire from the second pulley 230, in particular directly from the second pulley 230, and for redirecting the wire by a third redirection angle is provided. The third pulley 240 is rotatably mounted to the main frame portion 100 for rotation around a third pulley axis 242. The third pulley axis 242 is essentially perpendicular to both the spool axis 212a and the second pulley axis 232. Here, the wire exits from the third pulley 240 in a direction perpendicular to the image plane of Fig. 3 (in Fig. 2, on the right side of the third pulley 240), so that the third redirection angle is 90°.

[0040] Fig. 4 is a schematic view of a portion of a wire management unit according to further embodiments. Therein, the spool 212 mounted on the spool shaft 210, the wire 10, the first, second and third pulleys 220, 230 and 240 of Fig. 3 are shown. Compared to the side view of Fig. 3, Fig. 4 shows a front view, facing the spool 212 from the direction of the spool axis 212a (from the left side in Fig. 3). Further, Fig. 4 shows a fourth pulley 250 receiving the wire from the third pulley and redirecting the wire by a fourth redirection angle. The fourth pulley 250 is rotatably mounted to the frame for rotation around a fourth pulley axis 252. Here, the fourth redirection angle is about 90°. In other embodiments, the fourth redirection angle may be between 60° and 120°. The fourth pulley axis 252 is essentially parallel to the spool axis 212a. Further, the fourth pulley axis 252 is essentially perpendicular to the first pulley axis 222, the second pulley axis 232, and the third pulley axis 242. In other embodiments, the fourth pulley axis 252 may be essentially parallel to at least one of these axes. [0041] It is a general aspect, illustrated in the embodiment of Fig. 4, that an x-y-z reference frame may be defined as follows: the spool axis 212a defines an x axis, and the second pulley axis 222 being perpendicular to the spool axis defines a y axis, and the z axis is defined as the axis perpendicular to the x and y axes. The x, y and z axes defined in this manner are also shown in the other Figs. 2 to 7. As a general aspect, within this x-y-z reference frame, the spool 212 and the first and second pulley 220, 230 - and any other pulley if present in the embodiment - can be adapted to receive the wire such that at least one condition selected from the following list is satisfied:

the wire between the spool and the first pulley extends primarily along the z axis;

the wire between the first pulley and the second pulley extends primarily along the x axis the wire between the second pulley and the third pulley extends primarily along the x axis the wire between the third pulley and the fourth pulley extends primarily along the y axis the wire between the fourth pulley and the wire tensioner extends primarily along the z axis; and / or

the wire between the fifth pulley and the sixth pulley extends primarily along the y axis.

In some embodiments such as the embodiment of Fig. 4, even all of these conditions are satisfied. Here, "extending primarily along an axis" means that the component of the wire direction along the respective axis is larger than along any other one of the x, y and z axes.

[0042] Further, at least one condition selected from the following conditions, and in embodiments all conditions, may be satisfied:

the first pulley axis extends essentially in the y direction (more generally, the first pulley axis may extend within the y-z plane, which also includes the case of the first pulley being inclined with respect to the z direction);

the second pulley axis extends essentially in the y direction;

the third pulley axis extends essentially in the z direction;

the fourth pulley axis extends essentially in the x direction;

the wire is re-directed by the first pulley by a first redirection angle of about 90°;

the wire is re-directed by the second pulley by a second redirection angle of about 180°; the wire is re-directed by the third pulley by a third redirection angle of about 90°; and / or the wire is re-directed by the fourth pulley by a fourth redirection angle of about 90° to

120°.

[0043] Fig. 5 shows a portion of a wire management unit in a perspective view. The spool 212, mounted on spool shaft 210, and the pulleys 220, 230 and 240 are arranged as shown in Fig. 4. Additionally, a recess as described above in conjunction with Fig. 3 (recess 116) can be seen. Further, the pulley carrying unit 224 is provided as a retractable or telescopic bar. The retractable or telescopic bar is longitudinally movable along a bar axis parallel to the spool axis. The bar is longitudinally movably mounted to a wall portion of the main frame portion 100, more precisely of a wall portion of the recess 116.

[0044] Further, in the embodiment of Fig. 5 the main frame portion 100 includes a mounting member 114, to which the second and third pulley 230, 240 are mounted. The mounting member 114, being part of the main frame portion, is rigidly connected to the chassis of the wire saw device. While other designs of the mounting member are possible, in the specific embodiment of Fig. 5 the mounting member is a bar, more specifically an L-shaped bar with a first leg 114a extending to a side surface of the main frame portion 100 (i.e., extending parallel to the x axis), and with a second leg 114b forming an essentially right angle with the first leg and extending to a top surface of the main frame portion (i.e., extending parallel to the z axis). Independently from the shown embodiment, it is a general aspect that the first pulley 220 and the second pulley 230 (and, if present, also other pulleys such as a third and / or fourth pulley) are mounted on a common mounting member, especially on a one-piece mounting member.

[0045] Fig. 6 shows a perspective view of a wire management unit according to a further embodiment. The embodiment of Fig. 6 includes the elements shown in Fig. 5, and the above description of Fig. 5 also applies to Fig. 6. Further, a fourth pulley 250 is shown. The fourth pulley 250 is arranged as shown in Fig. 4, so that the corresponding description of Fig. 4 applies to Fig. 6 as well. The fourth pulley is mounted on the mounting member 114. The embodiment of Fig. 6 further includes a wire tensioner for controlling the tension of the wire. The wire tensioner includes a fifth pulley 260 rotatably mounted to the frame for rotation around a fifth pulley axis 262 and a sixth pulley 270 rotatably mounted to a movable element 274 for rotation around a sixth pulley axis 272. The movable element 274 is movably mounted on the main frame portion. The movement of the movable element 274 may be controlled by a motor, or the movable element 274 may be pre-biased, e.g., by a spring, for controlling the wire tension. In Fig. 6, the movable element 274 is shown as a pre-biased swivel lever. The wire tensioner receives the wire 10 from the fourth pulley 250 and provides the wire 10 to the wire web (to the right of the wire management unit shown in Fig. 6). More precisely, the fifth pulley 260 receives the wire 10 from the fourth pulley 250 and deflects the wire by a fifth deflection angle, and then the sixth pulley 260 receives the wire 10 from the fourth pulley 250 and deflects the wire by a sixth deflection angle.

[0046] With the x-y-z reference frame defined above, it is a general aspect, illustrated in the embodiment of Fig. 6, that at least one condition (and in some embodiments, even all conditions) selected from the following list is satisfied:

the wire tensioner is on a side of the spool 212 essentially opposite of the first pulley 220; the wire between the fourth pulley and the wire tensioner, more specifically between the fourth and the fifth pulley, extends primarily along the z axis;

the wire between the fifth pulley and the sixth pulley extends primarily along the y axis; the wire leaves the sixth pulley essentially parallel to the y axis;

the fifth and sixth pulley having respective axes each extending essentially in the x direction;

the fifth redirection angle is in the range of about 60° to 90°, specifically in the range of about 80° to 90°; and/or

the sixth redirection angle is about 180°.

[0047] Generally, in embodiments which may be combined with other embodiments herein, the pulleys have at least one, and in some embodiments all, of the following radiuses: The spool shaft 210 has a diameter of about 150 mm. The first pulley 220 and the second pulley 230 have a diameter of between 100 mm and 150 mm, especially of 112 mm (here, the diameter means the diameter observed by the wire, i.e., diameter within the wire guiding groove). The third pulley 240 has a diameter of between 140 and 170 mm, especially of 158 mm. The fourth pulley 250 has a diameter similar to the first pulley 220. The fifth pulley 260 and the sixth pulley 270 have a diameter similar to the third pulley 240.

[0048] Continuing the description of Fig. 6, besides the wire handling section 200, which in the following will also be called primary wire handling section 200, the wire management unit of Fig. 6 also has a secondary wire handling section 300. Here, the terms "primary" and "secondary" are introduced for ease of identification, and do not imply any hierarchical or functional order of the wire handling sections, spools etc. The secondary wire handling section 300 is constructed similarly to the primary wire handling section 200 and has corresponding elements to the elements of the primary wire handling section 200. The elements of the secondary wire handling section 300 are denoted as "secondary" elements and assigned reference signs 310, 312, etc. corresponding to the corresponding "primary" elements 210, 212, etc. of the primary wire handling section 200. Thus, the secondary wire handling unit 300 has, e.g., a secondary spool shaft 310 for a spool 312, a secondary first pulley 320, a secondary second pulley 330, etc. The secondary first pulley 320 is rotatably mounted to a secondary pulley carrying unit 324 for rotation around a secondary first pulley axis 322, the secondary pulley carrying unit 324 being longitudinally movable along a secondary pulley motion track. The primary and the secondary wire handling sections 200, 300 are placed in y direction adjacent to each other. As a general aspect illustrated by, but independent of the shown embodiment, the primary and the secondary wire handling sections 200, 300 may be placed on a common wall portion of the main frame portion 100. Further, the primary and the secondary wire handling sections 200, 300 may be placed in a common compartment of the wire saw device. Further, it can be seen in Fig. 6 that the primary spool 212 is of a different type than the secondary spool 312 (as can be seen from the absence of slits in the front flange of the secondary spool 312).

[0049] Generally, the secondary wire handling section 300 is formed in the same manner as the wire handling section 200 according to any embodiment described herein. The description of elements of the primary wire handling section 200 is therefore also applicable to the corresponding elements of the secondary wire handling section 300.

[0050] In an example mode of operation, henceforth called primary-to-secondary-spool sawing, the primary wire handling section provides wire from the primary first spool 212 to the web 10, so that the wire can be used for sawing in the web. Then, the secondary wire handling section 300 receives the wire 10 from the web. Thereby, the wire 10 is transported from the web to the secondary wire tensioner, more precisely to the secondary sixth pulley 370 and then to the secondary fifth pulley 360, from there to the secondary fourth pulley 350, from there to the secondary third pulley 340, from there to the secondary second pulley 330, from there to the secondary first pulley 320, and from there finally is wound onto the spool 312. Further, a controller controls the motion of the secondary first pulley 320 along the secondary pulley motion track so that the wire is wound in a controlled manner onto the wire carrying area of the secondary spool 312.

[0051] For receiving the wire, a secondary first pulley controller includes a wire winding pattern and is programmed to determine a desired wire winding position for winding the wire on the wire carrying area of the secondary spool, and transmits a moving command to the secondary first pulley moving device 328 for causing the secondary first pulley moving device 328 to move the secondary first pulley 320 to the desired wire winding position. [0052] The secondary second pulley 330 redirects the wire by about 180°, and the secondary first pulley redirects the wire by about 90°. Due to the large secondary second pulley 330 redirection angle, sharp tensions and vibrations during winding of the wire are avoided, as explained above, so that the wire can be securely wound with reduced risk of wire damage. Therefore, independently of the embodiment of Fig. 7, the secondary second pulley 330 should redirects the wire by not less than 60°, and the secondary first pulley redirects the wire by not more than 120°.

[0053] Generally, the spools in which new wire is provided are of a different type (say, a first spool type) than the spools onto which the used wire is wound (say, a second spool type). For example, the spools in which new wire is provided may be disposable spools from a wire manufacturer. Such spools may, on the other hand, be unsuitable for receiving used wire because they sometimes do not withstand the high wire tension of the used wire. In order to support these different spool types during primary-to-secondary-spool sawing, the primary spool shaft (i.e., the spool shaft of the primary wire handling section) may be adapted for carrying a spool of first type, and the secondary spool shaft (i.e., the spool shaft of the secondary wire handling section) is adapted for carrying a spool of second type, i.e., the second type being different from the first type.

[0054] Also, in some embodiments, which can be combined with any other embodiment(s) herein, the wire management section may support bidirectional sawing. Herein, bidirectional sawing is understood to be a sawing process during which first the wire is transported from the primary spool to the secondary spool, and thereafter is transported back from the secondary spool to the primary spool, and again from the primary spool to the secondary spool, etc. Thus, for bidirectional sawing the (primary) spool 212 is adapted for providing wire to the wire web and is also adapted for receiving used wire from the wire web. Likewise, a secondary spool 312 may be adapted for providing wire to the wire web and is also adapted for receiving used wire from the wire web.

[0055] For the bidirectional sawing, a controller is adapted for sending actuating commands to the primary spool shaft and to the secondary spool shaft, the actuating commands causing, in a first step, the first spool shaft to unwind wire to the second spool, and causing, in a second step, the second spool shaft to unwind wire to the first spool.

[0056] Fig. 7 shows a schematic view from above of a portion of a wire management unit according to further embodiments described herein. The embodiment of Fig. 7 generally corresponds to the embodiment of, e.g., Fig. 4 except for the features mentioned below, most notably the arrangement of the pulleys. Here, in the xyz coordinate system in which the x axis is defined by the spool axis 212a, and the y axis is defined by the second pulley axis 232 (pointing in a vertical direction), the first pulley axis 222 may be in the z direction or may be inclined with respect to the z direction, but lie within the y-z plane. The second and third pulley axes 232, 242 are in the y direction. The fourth pulley axis 252 is in the z direction.

[0057] Hence, the wire 10 is deflected by the first pulley 220 in a direction towards a wall element of the main frame 100. Then, the wire 10 is deflected by the second pulley 230 in a direction away from the wall element of the main frame 100. In this embodiment, the first deflection angle is about 90°, the second and third deflection angle is about 180°, and the fourth deflection angle is about 90°.

[0058] Fig. 8 shows a schematic top view of a wire saw device 1 being a squarer. The squarer includes a wire management unit with a first wire handling section 200 and a second wire handling section 300. Further, the wire saw device 1 has a working area 400, in which the wire 10 forms a wire web 410 in which the actual sawing process is performed.

[0059] The wire management unit including the first wire handling section 200 and the second wire handling section 300 may be in accordance with any embodiment described herein, e.g., the embodiment shown in Fig. 6. The wire handling sections 200 and 300 each have a wire spool and a plurality of pulleys for redirecting the wire 10 towards the wire web 410. The wire saw 1 further includes pulleys 420, 430 for redirecting the wire from the wire management unit to the wire web. Further, in the working area 400, a plurality of pulleys 412 are arranged for guiding the wire such that the wire web is created. In Fig. 6, a matrix-like wire web of the squarer is shown with cutting wire sections in two mutually orthogonal directions. The wire web may have, for example, six cutting wire sections in each of the two mutually orthogonal directions. Alternatively, a cropper wire web may be provided, e.g., as disclosed in European Patent Application No. 08154493.4, which is enclosed herein by reference, see, e.g., Fig. 1 thereof. In the working area 400, a specimen supply plate is provided (not shown) for carrying the specimen to be sawed. The specimen supply plate is grooved, so that during sawing the wire can pass through the grooves while the specimen is carried by the remainder of the plate.

[0060] Further, the wire management unit has a coolant system 500. The coolant system 500 includes a coolant tank 510 for storing coolant (generally slurry), a coolant supply line 520 for supplying coolant from the coolant tank 510 to the working area 400, and a coolant return line 530 for returning coolant from the working area 400 to the coolant tank 510. The coolant supply line 520 has a plurality of nozzles for spraying the coolant onto the wire within the wire web. The nozzles may be arranged along a square-shaped boundary of the wire web 410. While only one supply line 520 is shown, there may be more than one supply line, e.g., a supply line for each side of the square-shaped boundary of the wire web (i.e., a total of four supply lines), each supply line supplying coolant to a plurality of spray nozzles (e.g., six spray nozzles for each of the six wire sections per side of the wire web 410).

[0061] In the case of diamond wire, slurry is not needed, but it is still advantageous to cool the diamond wire during cutting. In this case, the slurry can be replaced by some other coolant such as a water-based cooling liquid. In this case, the cooling system can be advantageously adapted to the water-based cooling liquid as described below.

[0062] Fig. 9 shows a spray nozzle 540 especially adapted for a diamond wire for which non- slurry liquid coolant, such as a water-based coolant, is used. The spray nozzle 540 receives the coolant via the coolant supply line 520 shown in Fig. 8, and is adapted for spraying the coolant onto the wire 10. The spray nozzle 540 is generally shaped as a cylindrical body (with vertical cylinder axis in Fig. 9) with an indentation (on the left side of the body in Fig. 9) in which the nozzle outlet is provided. In Fig. 9, the spray nozzle system 540 sprays some coolant in a spray direction 542 onto the wire 10. Here, the coolant spray has some spread, and the spray direction 542 (dashed line) is defined as the central or main direction of the spray around which the spray is spread. It is advantageous that the angle 544 between the spray direction 542 and the wire 10 is between 90° and 180°, between 120° and 170°, especially about 150°. This large angle allows for efficient cooling of the wire by the cooling liquid. Also, such a large angle allows the spray of coolant to be always on the wire 10, independently from the groove used on the wire guides.

[0063] Fig. 10 shows a coolant tank system of the cooling system 500 of Fig. 8 in a perspective view. The coolant tank is adapted for a non-slurry coolant, especially a water- based coolant, and hence, is particularly useful for diamond wire. The coolant tank system has a coolant tank volume 510 for storing the coolant liquid. Further, the return line 530 is directly connected to the coolant tank volume 510 for directly returning the coolant liquid from the working area of the wire saw to the coolant tank volume 510 (see also Fig. 8). Here, directly returning means that there is no pump in the return line 530 between the working area 400 and the coolant tank volume 510. Further, the coolant tank return line 530 is connected to the coolant tank volume 510 at a connection portion of the coolant tank volume 510. Advantageously, the connection portion is a bottom portion, arranged below a minimum cooling liquid level during normal operation. Both the absence of a pump and arrangement at the bottom portion of the coolant tank volume 510 significantly reduce foam formation in the coolant tank volume 510, which may otherwise be a problem for water-based coolant liquid. The coolant tank return line 530 may optionally also include an inlet line for filling a fresh supply of coolant to the tank volume 530. Further, the coolant tank volume 530 is shaped with an inclined bottom surface leading to an outlet (not shown) at its lowest portion. Further, the tank volume 530 is connected to the coolant liquid supply line 520 via a pump 522, which is, e.g., a pneumatic pump.

[0064] According to a general aspect, which can be combined with any embodiment described herein, a controller of the cooling system 500 may have a drain routine programmed to cause an actuator of the outlet to open the outlet for draining the tank, i.e., removing all coolant liquid from the tank (except a possible small quantity of leftover coolant). In other embodiments, the pump 522 or a further pump (e.g., a pneumatic pump) is connected to a drain line (not shown). In this case, the drain routine can alternatively or additionally be programmed to cause the pump to pump the coolant liquid from the tank for draining the tank. This allows easy replacement of the coolant, without removing the coolant tank volume 510 from the wire saw apparatus.

[0065] In the following, some general aspects of the embodiments described herein will be summarized. Each of these general aspects can be combined with any other general aspect, within any embodiment described herein, to generate yet another embodiment.

[0066] According to an aspect, a wire saw device and/or portions thereof such as the wire handling portions, especially the pulleys, the wire spool shaft and/ or the wire spool, can be adapted for diamond wire, and methods of operating can be performed with diamond wire. This can, for example, be done by adapting the groove structure of pulleys and guiding elements with an appropriate pitch of grooves, a different depth of grooves and/or a different shape of grooves than for conventional such elements. Thereby, typically the cutting speed can be increased, e.g., by a factor of 2, the energy consumption of the wire saw device can be reduced and, further, as yet another example, the costs of squaring silicon ingots or wafering silicon can be significantly reduced. [0067] According to a further aspect, the first pulley and the second pulley are arranged such that during operation the wire is redirected by the first pulley by a first redirection angle of not more than 120°, and that the wire is redirected by the second pulley by a second redirection angle of not less than 60°, for at least one location of the first pulley on the first motion track, and in embodiments for any location of the first pulley on the first motion track. A similar effect can be obtained by the alternative aspect that the second redirection angle is larger than first redirection angle.

[0068] According to a further aspect, the spool includes a wire carrying area with a wire carrying length along the direction of the spool axis, is adapted for providing the wire towards the wire web during unwinding of the wire from the spool, and is rotatably mounted to the main frame portion for rotation around a spool axis.

[0069] According to a further aspect, the first pulley axis is oriented at an angle of essentially 90° with respect to the spool axis. According to a further aspect, the pulley motion track is arranged such that, for any lengthwise position of the wire on the coil, there is a position of the first pulley on the pulley motion track such that the wire is fed to the first pulley twist- free, i.e., entering and exiting the respective pulley tangentially. According to a further aspect, the first pulley motion track is essentially parallel to the rotation axis. According to a further aspect, the spool has a wire carrying area, and the first pulley motion track has a length of at least 90% of the length of the wire carrying area.

[0070] According to a further aspect, the wire management unit further includes a first pulley wire tracking system allowing actuation of the first pulley moving device in response to a detected wire position. According to a further aspect, the first pulley wire tracking system includes: a first pulley moving device being at least one element selected from the group of a linear actuator, a linear motor, a pneumatic cylinder, and a motor with a worm drive; a wire position detection device adapted for detecting the wire position along the direction of the motion path; a first pulley position controller being operatively connected to the wire position detection device for receiving the detected wire position, and being adapted for determining a target position, and being operatively connected to the first pulley moving device for transmitting a moving command causing the first pulley moving device to move the first pulley to the target position.

[0071] According to a further aspect, the first pulley axis and the second pulley axis have an angle of less than 90° with respect to each other and are, according to a further aspect, essentially parallel to each other. According to a further aspect, the first and second redirection angles are directed in opposite winding directions to one another. According to a further aspect, for any position of the first pulley, the first pulley and second pulley are arranged to each other such that the wire exits from the first pulley twist-free, is fed to the second pulley twist-free. According to a further aspect, for any position of the first pulley, the first pulley and second pulley are arranged to each other such that the wire between the first and the second pulley extends in the direction of the pulley motion track.

[0072] According to a further aspect, the wire management unit further includes a third pulley adapted for receiving the wire from the second pulley and for redirecting the wire by a third redirection angle, wherein the third pulley is rotatably mounted to the frame for rotation around a third pulley axis, and a fourth pulley adapted for receiving the wire from the third pulley and for redirecting the wire by a fourth redirection angle, wherein the fourth pulley is rotatably mounted to the frame for rotation around a fourth pulley axis. According to a further aspect, the third pulley axis is essentially perpendicular to both the spool axis and the second pulley axis. According to a further aspect, the third redirection angle essentially 90°. According to a further aspect, the fourth pulley axis is essentially parallel to the spool axis. According to a further aspect, fourth pulley axis is essentially perpendicular to the third pulley axis. According to a further aspect, the fourth redirection angle is between 60° and 120°. According to a further aspect, the first pulley is adapted for receiving the wire directly from the spool. According to a further aspect, the second pulley is adapted for receiving the wire directly from the first pulley. According to a further aspect, the third pulley is adapted for receiving the wire directly from the second pulley. According to a further aspect, the fourth pulley is adapted for receiving the wire directly from the third pulley.

[0073] According to a further aspect, the wire management unit further includes a wire tensioner adapted for controlling the tension of the wire. According to a further aspect, the wire tensioner receives the wire from the fourth pulley. According to a further aspect, the wire tensioner includes a fifth pulley rotatably mounted, e.g., to the frame for rotation around a fifth pulley axis and a sixth pulley rotatably mounted, e.g., to a resilient element for rotation around a sixth pulley axis.

[0074] According to a further aspect, the first and second pulley, and any other pulleys if present in the embodiment, are arranged such that for any lengthwise position of the wire exiting the coil, there is a position of the first pulley on the pulley motion track such that the wire is exiting and entering any one of the coils essentially tangentially, i.e., twist-free. [0075] According to a further aspect, the wire management unit is adapted for the wire being a diamond wire, i.e., including diamonds. According to a further aspect, the main frame portion is rigid, and rigidly connectable or connected or integral with the chassis of the wire saw device. According to a further aspect, the embodiment is an upgrade tool for upgrading an existing wire management unit of a wire saw, and / or for upgrading an existing wire saw, especially for upgrading it such as to be adapted to diamond wire.

[0076] According to a further aspect, the main frame portion includes a mounting member such as an L-shaped bar, to which the second, third and fourth pulley are mounted. According to a further aspect, receiving means directly receiving, so that, e.g., the first pulley is adapted to receive the wire directly from the first spool, the wire not being influenced by any other element therebetween. According to a further aspect, the wire arrangement described herein is the arrangement of an operational state of the device.

[0077] According to a further aspect, the spool axis defines an x axis, the second pulley axis being perpendicular to the spool axis defines a y axis, and the z axis is defined as the axis perpendicular to the x and y axis, and wherein the spool and the first and second pulley, and any other pulley if present in the embodiment, are adapted to receive the wire such that at least one condition (and in some embodiments, all conditions) selected from the following list is satisfied: the wire between the spool and the first pulley extends primarily along the z axis; the wire between the first pulley and the second pulley extends primarily along the x axis; the wire between the second pulley and the third pulley extends primarily along the x axis; the wire between the third pulley and the fourth pulley extends primarily along the y axis.

[0078] According to a further aspect, the spool is adapted for providing wire to the wire web and is also adapted for receiving used wire from the wire web. According to a further aspect, the spool has a wire carrying area, and the first pulley position controller includes a wire winding pattern and is programmed for determining a target position, and being operatively connected to the first pulley moving device for transmitting a moving command thereto for causing the first pulley moving device to move the first pulley to the target position. According to a further aspect, the wire handling section is a primary wire handling section, the wire management unit further including a secondary wire handling section. According to a further aspect, the primary wire handling section has a spool shaft that is adapted for carrying a spool of the first type, and the secondary wire handling section has a spool shaft that is adapted for carrying a spool of the second type. [0079] According to a further aspect, a wire saw device is provided; the wire saw including a wire management unit according to any one of the embodiments described herein, wherein the main frame portion is rigidly connected to a chassis of the wire saw device. According to a further aspect, the wire saw device is an element selected from the group consisting of a wire saw, a multiple wire saw, a squarer, and a cropper. The present wire management unit is particularly useful for a squarer.

[0080] According to a further aspect, a method of operating a wire saw device having a main frame portion, the method including providing wire from a spool; moving a pulley carrying unit longitudinally along a pulley motion track; receiving the wire from the spool by a first pulley and redirecting the wire by the first pulley, the first pulley being rotatably mounted to the pulley carrying unit for rotation around a first pulley axis; receiving the wire from the first pulley by a second pulley and redirecting the wire by the second pulley, the second pulley being rotatably mounted to the main frame portion for rotation around a second pulley axis, whereby the second pulley receives a greater load due to wire tension of the wire than the first pulley.

[0081] According to a further aspect, the wire is diamond wire. According to a further aspect, the method further includes forming a wire web with the wire. According to a further aspect, the method includes redirecting the wire by the first pulley by a first redirection angle of not more than 120°, and redirecting the wire by the second pulley by a second redirection angle of not less than 60°. A similar effect can be obtained by the alternative aspect that the second redirection angle is larger than first redirection angle.

[0082] A further aspect is directed to a wire management unit adapted for a wire saw device having a wire forming a wire web for cutting, the wire management unit including: a primary wire handling section having a primary spool shaft adapted for carrying a primary spool, and a primary first pulley adapted for receiving the wire from the primary spool and for redirecting the wire, the primary first pulley being rotatably mounted to a primary pulley carrying unit for rotation around a primary first pulley axis, the primary pulley carrying unit being longitudinally movable along a primary pulley motion track; the wire management unit further including: a secondary wire handling section having a secondary spool shaft adapted for carrying a secondary spool, and a secondary first pulley adapted for redirecting the wire, the secondary first pulley being rotatably mounted to a secondary pulley carrying unit for rotation around a secondary first pulley axis, the secondary pulley carrying unit being longitudinally movable along a secondary pulley motion track. Such a wire management unit has the advantage that it allows for bidirectional sawing operation. According to an aspect, the wire management unit is adapted for bidirectional saw operation, wherein during sawing in a first direction, the primary spool provides the wire towards the wire web, and the secondary spool receives the wire from the wire web, and wherein during sawing in a second direction the secondary spool provides the wire towards the wire web, and the primary spool receives the wire from the wire web. According to a further aspect, the primary and / or the secondary spool is adapted for providing wire to the wire web and is also adapted for receiving used wire from the wire web. According to a further aspect, the primary wire handling section has a spool shaft that is adapted for carrying a spool of first type, and the secondary wire handling section has a spool shaft that is adapted for carrying a spool of second type. According to a further aspect, the primary spool and the secondary spool are located in a single cabinet, and / or are mounted to a common wall portion of the main frame portion. According to a further aspect, a controller includes a wire winding pattern and has a tracking program programmed to actuate the primary and / or secondary first pulley moving device in response to a detected wire position of the wire at the respective spool, and a winding program programmed to determine a desired wire winding position for winding the wire on the wire carrying area of the primary and / or secondary spool, and transmits a moving command to the primary and / or secondary first pulley moving device for causing it to move the respective pulley to the desired wire winding position.

[0083] While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.