Wire saw device

p0001The invention relates to a wire saw device according to the preamble of claim 1. In particular, the invention wire saw devices or, in a first case of application for sawing or cutting a crystalline ingot or ingots into a number of blocks or bricks or in a second case of application for sawing relates serve cutting of blocks or bricks into wafers. In the first use case including a wire saw apparatus is to be understood that cut a squaring of cylindrical monocrystalline material, such as. For example, silicon, carries out in blocks or multi-crystalline silicon in the form of parallelepipedal bars in blocks or bricks, and commonly referred to as Squarer is called.

p0002The crystalline ingot to be sawn or ingots have been previously prepared by a crystal growth process. In previous squaring process outside saws were used with diamond-coated saw blades or band saws. In more modern methods, the squaring is performed by means of a dicing saw wire through a corresponding wire saw apparatus to which a first application of the invention relates. The squaring turns an originally round monocrystalline ingot a square block with rounded corners, or a square, multicrystalline ingot large plurality of blocks with a square cross section. A second application relates to a wire saw device, which is used to both multicrystalline and monocrystalline material, in particular silicon, to produce wafers. The square shape formed during blocks or bricks are sawn into disc-shaped wafer.

p0003When sawing or cutting under both applications provide accurate guidance of the saw wire has to be achieved and it should be avoided overstressing the material.

p0004The saw wire can be a highly crack-resistant steel wire embedded in addition to its surface, for example, in a nickel alloy may comprise diamond grains. However, it may also be an existing from numerous individual fibers plastic wire having on its surface abrasive grains (see, for example<patcit id="pcit0001" dnum="WO2003041899A"><text>WO 2003/041899</text></patcit>).

p0005When sawing technology currently most widely used, the wire does not come directly to the material (silicon) into contact. For the Sägestellen are sprayed with a mixture of glycol or oil and silicon carbide grains, which is commonly referred to as "slurry". The silicon acts as abrasive medium, which causes the actual sawing through the material. Thus, it is strictly speaking not a saw, but a Drahttrennläppen.

p0006The invention is also the wire guide in the known as Squarer wire saw devices improve that form for sawing or cutting a crystalline ingot into a plurality of blocks, a preferably square-shaped wire frame of preferably intersecting cutting wires or cutting wire sections. However, the invention should not be limited to this type of wire saw devices. These Squarern the cutting wire is guided over a number of wire guide wheels and tensioned longitudinally moving, each wire guide plate has a plurality of grooves for guiding the cutting wire. On the four sides of each Squarers more wire guide disks in an array are rotatably mounted, which is also called a wire guide roller. The wire guide discs are mounted at defined intervals in order to achieve the desired cut widths. These devices are particularly suitable for the production of blocks are typically fabricated from 130μm which in the subsequent production step "Wafer dicing" to 200 microns thick solar wafer.

p0007Another type of wire saw apparatus is known eg from <patcit id="pcit0002" dnum="DE10003240A1"><text>DE 100 03 240 A1</text></patcit> known. This wire saw device is a multi-wire saw and serves in particular for cutting a silicon ingot into multiple wafers or semiconductor wafers. The device has for this purpose a wire group in which a cutting wire is guided over a plurality of grooved rollers, the grooves being mutually spaced, as required by the desired thickness of the wafer. Thus, these rollers act as provided with multiple grooves or channels roller- or cylindrical wire guide rollers. Accordingly, from the<patcit id="pcit0003" dnum="DE10003240A1"><text>DE 100 03 240 A1</text></patcit> discloses a wire saw device, wherein the roller-shaped guided over the wire guide rollers and cutting wires to be moved longitudinally under tension. This is also referred to as a multi-wire saw device takes for the process of the wafer sawing use.

p0008From the <patcit id="pcit0004" dnum="DE102007019566A1"><text>DE 10 2007 019 566 A1</text></patcit> it is known that the material of which consists of the coating of the wire guide rollers, and the contour of the plurality of grooves of the wire guide rollers of this wire saw apparatus must be adapted to hold the wear thereof to a minimum. Thus, the service life of the wire guide rolls are increased, the wire is optimal and quality characteristics of the wafer produced in this Multi Wire Saw such. B. Bow and Warp, positively influenced.

p0009From the <patcit id="pcit0005" dnum="EP1110652B1"><text>EP 110 652 B1 1</text></patcit> is a wire device (Multi Wire Saw) known to be performed at the also cutting wires through wire guide rollers. For optimum wire tension is maintained during the sawing process, tensile stress sensors (tension-sensor) are provided which measure or monitor the wire tension.

p0010In addition to maintaining optimum wire tension also needs to be ensured in any type of wire saw apparatus that the cutting wire in the respective groove on the wire guide roller (Multi Wire Saw) and wire guide plate (Squarer) remains. Particularly important to avoid that a so-called wire jump from one groove to another occurs. In the process of wafer sawing, however, each adjacent groove of the wire guide roller is already occupied by a running therein wire, whereby a wire jump rarer in this process, only leads to failure of two adjacent wafers for geometry-tolerance and a wire jump is usually tolerated. Wire jumps during wafer sawing usually have their origin in the wear of the grooves, such as those which<patcit id="pcit0006" dnum="EP1110652B1"><text>EP 110 652 B1 1</text></patcit> describes.

p0011Allen mentioned types of wire saw devices have in common that they for the product geometry determining precision guidance of the engaged on the workpiece wire segments in addition to said wire guide elements, so the wire guide rollers (Multi Wire Saw) or joined together to form the wire guide rolls wire guide wheels (Squarer), also have another wire guide elements for the purpose of determining the wire path, which are referred to below as a wire guide wheels, pulleys, guide rollers or Umlenkzylinderrollen concrete.

p0012Therefore, it is of general interest to keep the natural wear of the contact surfaces of the wire guide elements in borders, so the contact surfaces, which interact with the cutting wire in direct contact, such as not to allow all present in the machine pulleys, too much wear, so the cutting wire runs to the predetermined paths.

p0013Furthermore, it should be ensured that a wound on a supply roll and running through a transversely extended to wire movement leadership wire follows the windings of the supply roll or its transverse forces and thereby wanders freely on a vast Umlenkzylinderrolle and does not stick to the always occurring wear grooves of Umlenkzylinderrolle.

p0014In addition, it would be desirable to be able to determine the tension of the cutting wire at as many points between different wire guide elements.

p0015Accordingly, it is an object of the present invention to provide a wire saw apparatus in which the above mentioned drawbacks and requirements are overcome and solved in advantageous manner. In particular, to be achieved by the invention that<ul><li>Jumps of the wire can be detected from the predetermined groove of a wire guide plate out,</li><li>the wear of guide rollers of each type is detected,</li><li>is detected when the free migration of the wire is no longer given to the Umlenkzylinderrollen</li><li>the tension of the cutting wire can not be determined only in the vicinity of winding or unwinding.</li></ul>

p0016In particular, a so-called. Squarers for squaring of ingots to be reliably detected in a wire saw device in the way, when the saw wire from the predetermined groove of a wire guide wheel jumps.

p0017Even with wire saw devices to this or other nature to ensure that the natural wear of the contact surfaces of wire guiding elements can be early and automatically detected and prevents the cutting wire the intended track does not leave and / or does not stick in a forming wear groove.

p0018The object is achieved by a wire device having the features of claim 1.

p0019Accordingly, it is proposed that the wire saw apparatus comprises at least one sensor which is arranged in a surrounding region of at least one of the wire guiding elements and of the relative change of the current position of the cutting wire detects a predetermined as optimum position of position transverse to the longitudinal axis of the cutting wire.

p0020The wire saw device according to the present invention thus contains at least one sensor arrangement which serves for monitoring the position of the guided wire around the wire guide members, and thus to monitor in particular the wire guide in the device and / or the state of wear of the wire guide elements and / or the wire tension can ,

p0021As wire guide elements each type of wire guide elements in particular wire guide wheels, pulleys, guide rollers or Umlenkzylinderrollen be regarded considered. The respective sensor may be a position-sensitive detector or sensor, so be such that it detects a spatially resolved change the current position of the cutting wire. A spatially resolved change in the position of the cutting wire in the vicinity of a wire guide disc provides the indication of a wire jump into one of the adjacent grooves, or provides the indication of a no longer tolerable wear of the guide pulley or to a no longer tolerable wear of a Umlenkzylinderrolle or on an associated state change of the cutting wire. Also, the respective sensor can be a time-resolving sensor or detector, therefore be such as to detect a time-resolved change in current position of the cutting wire in order to detect an associated change in state of the cutting wire, and in particular wear and / or change of the tensile stress.

p0022The wire saw device can for example be designed as a multi-wire saw, cuts the block-like body of crystalline material, in particular ingots of silicon, cut into several slices or wafers, in particular by Drahttrennläppen or wire cut ribbons.

p0023The wire saw device may be configured for example as Squarer, especially cuts the block-like body of crystalline material, in particular ingots of silicon, divided into several blocks or bricks by Drahttrennläppen. In this case, in the surrounding region of one or more wire guide disc (s) at least in each case a sensor is arranged so that the sensor detects whether the cutting wire remains in that groove in which the cutting wire is guided or jumped into another groove.

p0024Typically located at each of the four sides of the called Squarer wire saw device, an arrangement of several such wire guide wheels. This arrangement can also be called a wire guide roller or composite of wire guide wheels. Preferably the sensors in a surrounding region, which includes the winding and / or the rolling of the cutting wire to or from the respective wire guide pulley. In particular, the respective sensor exactly comprises a groove of the respective wire guide pulley.

p0025It is here a sensor device is proposed that has at least one such sensor, and is mounted on a wire saw device.

p0026Thus the presented wire saw device with preferably a plurality of sensors is provided, which are aligned on the run in the groove cutting wires back and a possibly occurring wire jump safely and immediately recognize. Since the sensors are always aligned to a predetermined groove, and operator error when setting up the wire field be avoided as the laid wire must also be detected in the predetermined groove.

p0027In case of detecting a change in position that an intolerable state change, such as indicating a wire jump can, the separating or cutting process to be stopped. then there By eliminating the wire jump by manual intervention to prevent the possibility that in the event of continued Squarens an ingot up to 8 blocks for geometry errors to committee without manual intervention in the worst case, if, for example of an ingot with a footprint of 700mm x 700mm starts to be sawed into 16 blocks with dimensions of 156mm x 156mm. In addition to detecting is the Committee avoiding particularly necessary that a wire jump immediately detected and the machine can be brought to a standstill.

p0028Preferably, in the surrounding region of each wire guide washer at least one sensor is arranged in each case so that the sensor detects whether the respective cutting wire remains in that groove, in which the cutting wire is guided. The sensors are preferably mounted on the frame, which also carries the wire guide roll of the respective wire guide rings, or mounted on a bracket attached thereto. As sensors, for example, inductive, magnetic and / or optical sensors may be used. It is advantageous also if the respective sensor is a proximity sensor, ie. As a sensor which can detect metal objects without physical contact For this purpose, various types of sensors, such as a working electromagnetic induction Hochfrequenzoszillationstyp, an agent working with magnet sensor type or a capacitive sensor type, are used.

p0029Preferably, the wire saw device includes a control circuit connected to the sensors which processes a sensor signal coming from the sensor and which controls a stoppage of the longitudinally moving cutting wires, if at least one of the sensors indicates the occurrence of a jump wire. Preferably, the control circuit can also be integrated in an engine control unit for at least one motor drive for moving the cutting wires. The drive preferably includes a plurality of motors.

p0030The control circuit is preferably designed so that it comprises at least one comparator which compares the sensor signal with a predetermined threshold value. Also, the control circuit may comprise at least a first circuit stage, which checks whether a ground fault of the cutting wire is present. Because in an inexpensive variant the sensor is located in a metal housing which is in turn conductively connected to the device. Thus, once a possibly occurring touching the sensor, can be detected by the cutting wire and protective measures can be triggered. Furthermore, the control circuit may further comprise at least one second circuit stage, which continuously checks the function of the respective sensor. Preferably, a sensor with (in the sensor housing or cable) integrated amplifier is used so that the sensor function or the wiring between the sensor and amplifier can be checked via a separate output. Also, the control circuit having at least one linking stage, which linked to each other a plurality of sensor signals. This may be for example, a logical OR circuit.

p0031The invention and the advantages derived therefrom are described below and in detail by means of embodiments, reference being made to the accompanying drawings<dl id="dl0001" compact="compact"><dt>Figure 1 a) and b)</dt><dd>show in a front view and a side view b) are schematic illustrations of a wire saw device according to a first embodiment in the form of a Squarers with examples based on two wire guide wheels, the arrangement of the discs and the sensor and guiding the wire are shown.</dd></dl><dl id="dl0002"><dt>figure 2</dt><dd>shows schematically in a three-dimensional view of the structure of the wire saw apparatus according to the first embodiment.</dd><dt>figure 3</dt><dd>shows the <figref idrefs="f0001">Fig. 1</figref> and <figref idrefs="f0002">2</figref> in detail a section of a multi-grooved wire guide plate, and the close thereto arranged sensor for detecting wire jumps</dd><dt>figure 4</dt><dd>shows in a first embodiment of a control circuit according to the invention for the in <figref idrefs="f0001 f0002 f0003">FIGS. 1-3</figref> Sensors shown.</dd><dt>figure 5</dt><dd>shows a variant of the control circuit of the invention for in <figref idrefs="f0001 f0002 f0003">FIGS. 1-3</figref> Sensors shown.</dd><dt>Figure 6 a)</dt><dd>shows a schematic representation of another portion of a wire saw device (found in both a Squarer and a Multi Wire Saw) and represents a second application, wherein a sensor detects the position of the cutting wire in its upward or settlement.</dd><dt>Figure 6 b)</dt><dd>the portion of the wire saw apparatus as claimed in <figref idrefs="f0006">Fig. 6b</figref>), Wherein the up or winding the cutting wire is more advanced.</dd><dt>figure 7</dt><dd>the portion of the wire saw apparatus as claimed in <figref idrefs="f0006">FIG. 6a) and 6b</figref>) Shows, one caused by wear on a Umlenkzylinderrolle faulty wire guide and wire migration is detected.</dd><dt>figure 8</dt><dd>shows a schematic representation of a portion of a wire saw device according to a third use case, wherein a sensor detects the position of the cutting wire at a deflecting roller, in order to monitor the mechanical wear of the pulley.</dd></dl>

p0032The embodiments described below illustrate the versatile applications of the invention. The defined under the term "wire saw device" subject invention is to be understood generally and includes all devices for dividing crystalline material, such as wire saws for cutting blocks, bricks or pillars in wafer Squarer for cutting crystalline ingot in so-called blocks, Bricks or columns, etc .. As a "sawing" here is any Arte dicing of material understood by one or more cutting wires, especially the so-called Drahttrennläppen in which not the wire itself cut the material, but essentially an on or Kontakstelle ( n) which is introduced between the material and wire mixture of glycol or oil and with abrasive grains (so-called. slurry). The wire moves to the slurry or in the contact zones, so that the material is removed by means Drahttrennläppen. For guiding the at least one cutting wire wire guide elements are used, the various embodiments may have, such as wire guide wheels, guide rollers or Umlenkzylinderrollen, guide rollers, driven or idler pulleys, etc.<b>,</b>,

p0033In the wire saw device, instead of dividing of crystalline ingots in so-called blocks, bricks or pillars etc. by Drahttrennläppen also the process of Drahttrennschleifens apply. In wire cut-off grinding a wire is used, wherein the abrasive particles (eg, diamond particles) are metallically bonded to the surface of the wire.

p0034The <figref idrefs="f0001 f0002 f0003 f0004 f0005">Figures 1 to 5</figref> refer to examples relating to the wire guide in the wire-frame of a Squarers, wherein the sensors are arranged in the vicinity of the wire field, particularly in order to avoid the occurrence of wire jumps to wire guide wheels. The<figref idrefs="f0006">figures 6</figref>. <figref idrefs="f0007">7</figref> and <figref idrefs="f0008">8th</figref> describe other applications of the sensor arrangement in which particular unimpeded migration of the wire is to ensure on Umlenkzylinderrolle or the wear of the wire guide wheels to be monitored. The sensor arrangement for detecting the position of a saw wire is therefore not only limited to the detection of a wire jump to wire guide wheels or the wear of the wire guide wheels. This sensor arrangement can be found in all types of wire saw devices as Squarer or multiwire sawing application. Always is the sensor in the area surrounding a wire guide pulley or a similar position in the vicinity of a guide roller, a guide roller or a Umlenkzylinderrolle or the like. Arranged and detects the deviation of the actual position of the wire from its DESIRED position. These various applications will be described below with reference to the<figref idrefs="f0001 f0002 f0003 f0004 f0005 f0006 f0007 f0008">Figures 1-8</figref> described in detail.

p0035As a first exemplary recordable is first here with reference to the <figref idrefs="f0001 f0002 f0003">Figures 1 to 3</figref> described a wire saw device in the form of a Squarers on which a sensor according to the invention is mounted. The sensor is connected to a control circuit which based<figref idrefs="f0004">Fig. 4</figref> and <figref idrefs="f0005">5</figref> is described in two embodiments.

p0036The <figref idrefs="f0001">Figures 1a) and 1b</figref>) And 2 show different views of an inventive wire saw device in the form of a Squarers 100, the 200, divided by means of a cutting wire 140, a monocrystalline ingot 200 or multicrystalline ingots made of a crystalline material such as silicon into blocks or bricks.

p0037the <figref idrefs="f0001">figure 1</figref> shows by means of views a) and b) of example, the guide of the cutting wire 140 through wire guide elements in the form of guide rollers 120 and wire guide discs 110 and the arrangement of at least one sensor 135 for detecting the current wire-position and secure detection of a wire jump. Before it will be explained in more detail, to this first reference to the<figref idrefs="f0002">figure 2</figref> the general structure of Squarers be described.

p0038The <figref idrefs="f0002">figure 2</figref> shows this in a three-dimensional view of the Squarer 100, the (all one type of previously been enumerated wire guide elements) comprising a frame and a holder 130 for a plurality of wire guide elements in the form of wire guide wheels 110 and pulleys 120th The over the wire guide wheels guided cutting wire 140 intersects the cutting area and clamped there a wire frame 145, which is suitable for sawing of multi- or mono-crystalline blocks or ingots. The cutting wire 140 is passed over the pulleys 120, which are located at the top of the bracket 130 to the respective wire guide wheels 110, which are located at the bottom of the bracket 130 and the deflection of the cutting wire in the horizontal direction of cutting as well as for accurate wire guide to care.

p0039In the vicinity of each wire guide plate 110, a sensor 135 is provided which is aligned with the guide and the actual position of the cutting wire to detect possibly occurring wire jumps immediately. Because by the machining process is defined, in which groove the cutting wire to be located. Should the cutting wire, leaving Anyway, this groove or optimum position for any reason, this is immediately recognized by the invention proposed here and shown or evaluated.

p0040The sawing and cutting wire 140 used here is about 250 microns only slightly thicker than a human hair. The cutting of an ingot 200 (see also<figref idrefs="f0001">Fig. 1</figref>) With a wafer-thin brass-coated steel wire usually takes 5 to 7 hours. Here, the wire performs a pendulum motion by the wire at a rate of up to 15 m / s is moved backwards and forwards through the material. The roller system shown ensures that the saw wire passes through all the Sägekanäle. For cutting the ingot 200 in, for example, sixteen blocks a wire coil is required with around 400 kms wire.

p0041The wire guide is now on the basis of <figref idrefs="f0001">figure 1</figref> described in more detail:

p0042The <figref idrefs="f0001">figure 1</figref> shows by means of views a) and b) an example of the guiding of a cutting wire 140 via the guide rollers 120 and wire guide discs 110 and the arrangement of the sensor 135 for the safe detection of a wire jump. The rollers on the guided wire 140 is placed through the wire guide wheels 110 in the horizontal cutting position and thus accurately positioned for sawing the ingot 200th The respective wire guide wheels 110 have to more grooves (see also<figref idrefs="f0003">figure 3</figref>). A sensor mounted on the holder 130, respectively in the vicinity of the wire guide plate 110 sensor 135 checks the exact position of the cutting wire 140 and reports a wire jump that might arise. The detected by the sensor environment A corresponds to a narrow range in the vicinity of the grooves of the wire guide pulley 110. The sensor shown 135 is configured as a proximity sensor in the form of a Hochfrequenzoszillationstyps here, having a measuring coil an oscillation circuit comprises an amplitude detection circuit and an output circuit. All circuit elements can be integrated in one housing. Alternatively, the measuring coil from be incorporated in a separate measuring head and connected via a cable to the oscillating circuit, which is mounted with the remaining circuit elements in another housing. In between is a cable (coaxial cable), in which an amplifier can be integrated, if it has a certain length. By means of the oscillation circuit and the measuring coil a high-frequency magnetic field is generated, the generated in which in the vicinity metal object (here in the cutting wire), an induction current (eddy current). The smaller the distance between the sensor and metallic object, the greater the induced current and the greater the load in the oscillating circuit. These changes are detected in the sensor by the therein amplitude detection circuit and the output circuit as a measurement signal or sensor signal (s. Signal S<figref idrefs="f0001">Fig. 1</figref>) Is output.

p0043There are various types of proximity sensor conceivable such as switching sensor with internal or external electronics or amplifiers, or as preferred as switching sensor adjustable with an external amplifier. Thus, preferably located in the sensor itself is always a part of the electronics or even the entire electronics. The electronics in the sensor is not located or the amplifier as in cables, located in a connector or be designed as a separate amplifier.

p0044The <figref idrefs="f0003">figure 3</figref> shows this in detail the upper portion of the wire guide plate 110 with the grooves provided therein. Here 10 equidistant grooves are present, for example, of which the grooves R1, R5 and R10 provided with a reference numeral here as an example. The central groove R5 is intended to define the current and desired ideal position or target position P0 of the cutting wire 140th The mounted in the immediate vicinity of the sensor 135, which represents, for example, a proximity switch with built-in amplifier, detects the current and optimum position of the cutting wire. Now Once a wire jump from the current groove R5 should occur in a different groove into it, this is detected by the sensor 135 immediately. The sensor is connected to a circuit to be described later, which carries out an evaluation of the sensor signal and the driving means (not shown) in a wire jump holding the wire saw apparatus.

p0045The <figref idrefs="f0004">figures 4</figref> and <figref idrefs="f0005">5</figref> show in further detail Examples of the structure of the sensor device according to the invention with an associated control circuit.

p0046In the <figref idrefs="f0004">figure 4</figref> For example, a first control circuit 150 is shown, which is connected to the sensor 135th The sensor provides a sensor signal S present at the input of the control circuit 150th The control circuit 150 has in particular a comparator or differential amplifier 151 which recognizes from a threshold detection, whether the sensor signal S indicates a wire jump or not. The differential amplifier 151 is a trigger stage 152 downstream, which forms a rectangular trigger signal and this leads to a link stage 153rd The linking stage, which is designed here as a logical OR gate, connected a plurality of sensor signals and thus causes the output of the control circuit a control signal ST is generated as soon as at least one of the sensors detects a wire jump. The link stage 153 is a circuit connected downstream of the output pulse shaping, which generates a floating control signal ST, which is performed for instance on the actual drive control (engine control) for electric motors that drive the wire saw device.

p0047The control circuit 150 is additionally provided with a first switching stage 155, which checks whether a short to ground of each wire is present. Thus, an additional security feature is incorporated. Moreover, the circuit may also comprise an additional second stage circuit 156 which causes an automatic safety / functional control of the sensor.

p0048The data processed by the circuit 150 sensor signals can not only by the wire jump sensors such as the sensor 135, but also on further sensors originate, for example, measure or detect the wire tension. Thus, 150 different sensor signals can be combined and processed in the control circuit. The drive of the wire saw apparatus is for example also stopped when the wiring tension should lie outside a specifiable tolerance range.

p0049The <figref idrefs="f0005">figure 5</figref> shows another embodiment of the control circuit 160, which corresponds to a simplified embodiment of the above-described circuit 150th The sensor of the 135 'coming signal S is led to a differential amplifier 161, which also acts as a comparator here. The differential amplifier 161 provides a signal preprocessing by converts the analog sensor signal into a switching level with a defined voltage range of for example, 0 or 15 volts. A subsequent trigger level 162 is the pulse form and for additional security, the standard-compliant slew rates are produced for the subsequent stage. For this purpose, for example, a monostable multivibrator may be used. In the example shown, is followed by a combining stage 163, which is also implemented as OR gate and a plurality of sensor signals or signals from a plurality of sensors 135 'and 136' merges. This is followed by the output of pulse shaping in a corresponding stage 164, so that finally a control signal ST 'is generated which causes the stop function in the machine control. The inventive control circuit 150 or 160 can also be integrated in the machine control.

p0050The here on the basis of <figref idrefs="f0001 f0002 f0003 f0004 f0005">Figures 1 to 5</figref> previously described embodiments of the invention are particularly suited to the respective wire guide element (wire guide pulley, pulley, guide roller, Umlenkzylinderrolle etc.) to reliably detect a change in the current position of the cutting wire. By means of a control circuit and a transmitter is realized therein generates a control signal or a switch-off for the drive of the wire saw apparatus, in the case of a jump wire. In case different sort position changes of the cutting wire such. B.<figref idrefs="f0006">Fig. 6</figref>. <figref idrefs="f0007">Fig. 7</figref> and <figref idrefs="f0008">Figure 8</figref> shown, the control signal does not necessarily lead to a shutdown of the drive but can result in a message at the end of the current cutting process to examine the monitored item and replaced if necessary.

p0051The invention has inter alia the advantage that a wire jump safely identifies and immediately and thus the engine or the drive is stopped immediately. at a Neueinrichten the wire field also eliminates an additional control of the position of each wire in the intended groove.

p0052The control circuit according to the invention is characterized in particular by the fact that they at the sensor output outputs a reset pulse for a memory cell D flip-flop after a triggering any input edge. This is thus a switching sensor which is equipped with a D-latch. Thus, signaling (eg, visual alarm display) is an event occurs, which can also be very short, are set and avoided that events are not recognized by serving staff (absence, to short temporary incidents, etc.). Triggering is particularly used to increase immunity and variability. For the electronics may preferably be half of the sensor supply voltage to be used. This contributes to a sufficient noise immunity. For the logic linking a plurality of sensor input signals can be made of a conventional logic circuit, particularly preferably low-power-loss components are used. The sensor type, for example, is a DC proximity sensors with amplifier.

p0053The above reference to the <figref idrefs="f0001 f0002 f0003 f0004 f0005">Figures 1 to 5</figref> Described embodiments relate to an invention designed according to wire saw device in the form of a Squarers having an over wire guide wheels run and tensioned longitudinally moving cutting wire, each wire guide plate has a plurality of grooves for guiding the cutting wire. It is understood that the invention can be applied to any other type of wire saw devices, wherein at least one cutting wire is guided in a groove, and it is irrelevant whether the lead is effected by means of a wire guide plate in the narrower sense. Therefore, the term "wire guide plate" are understood not tight, but should include any type of wire guide elements which can be provided with grooves, such as rollers, wheels, rollers, cylinders and the like.

p0054Based on <figref idrefs="f0006">Figure 6a), 6b</figref>) and <figref idrefs="f0007">7</figref> another embodiment of the invention will now be described, namely a sensor system for monitoring a non-affected rollers wear wire guide during an upward or settlement process:

p0055The <figref idrefs="f0006">6a</figref>) Shows a portion of a device according to the invention, in which the cutting wire called 140 via a plurality of wire guiding elements in the form of various guide rollers 121 and 122 (also guide roller), and an extended Umlenkzylinderrolle 124 is performed on a wire supply spool 125 to be wound there. As a counterpart to the shown wire supply spool 125 is a (not shown) further wire supply reel is provided, by which the cutting wire 140 is unwound in the pulling direction Z is led through the material and then, as shown in<figref idrefs="f0006">Figure 6 a)</figref> is shown, over the guide roller 121 and guide roller 122 and the Umlenkzylinderrolle 124 on the wire supply reel 125 and wound up there.

p0056The successive exhaust and again winding the wire is an essential functional feature of a wire saw machine, since it is advantageous to move the wire in the so-called hunting section. In this case, from the unused wire before Consultative coil unwound a certain length of wire and coiled after passing through the material to be sawn object on a collection spool for used wire, then placed the wire movement to a standstill, and then by means of a rearward movement of the wire a somewhat smaller length wire of the Altdrahtspule fetched and rewound back onto the supply reel. And so on. Typical lengths are 300 m in the forward direction and 280 m in the reverse direction. The winding of the wire used is done here with a pitch of a few mm per spool revolution at a used bobbin length of 100 mm to 200 mm.

p0057The cutting wire 140 must be evenly distributed as possible wound on the wire supply reel 125th For this purpose, the guide roller 122 moves vertically up and down, the cutting wire 140 slides or moves across the Umlenkzylinderrolle 124th This Umlenkzylinderrolle 124 has an elongated roll-like form and consists of a plastic, preferably a material of low density, high wear resistance and the highest possible static friction against the wire.

p0058The <figref idrefs="f0006">6a</figref>) Shows the cutting wire 140 in the upper position, therefore the upper end of Umlenkzylinderrolle 124, and the <figref idrefs="f0006">figure 6b</figref>) Shows the cutting wire 140 at the lower position, so the lower end of Umlenkzylinderrolle 124. As can be seen, changes in accordance with the vertical position of the cutting wire 140 on the Umlenkzylinderrolle 124. Because of the angle of deflection of the wire to the deflection roller 121 and therefrom to resulting, in the image downward thrust on the wire of the wire during the downward movement of the roller 122 follows voluntarily. This voluntary consequences is only impeded when there is due to wear resulting circumferential grooves on the Umlenkzylinderrolle 124th By means of a sensor 135, which is rigidly connected to the guide roller 122, the position of the cutting wire 140 is monitored to this leadership 122nd If no wear on the rollers 122 and 124 occurs or manifests itself, this position remains unchanged and is always located on the upper inclined plane of the guide roller 122nd

p0059The <figref idrefs="f0007">figure 7</figref> shows the situation in which on the Umlenkzylinderrolle 124 disturbing grooves have formed due to material wear, of which at least one wear groove V formed so deep that the cutting wire 140 remains in its downward movement (walking) hanging in this wear groove V. In such a case, the cutting wire 140 is no longer uniformly distributed are wound on the wire supply reel. The sensor 135 but this case is detected immediately because the actual position P # of the cutting wire 140 briefly differs (depending on up or unwinding) and of the relative prescribed for leadership 122 target position P0 up or down sensor 135 detects this. In this case, as shown in Figure 6c, raises the cutting wire 140 of the guide roller 122 either decreases, resulting in an increase in the distance between the cutting wire 140 and the upper running surface of the guide roller 122 (in the case drawn here no wire redirection occurs on the guide roller 122 ) or the cutting wire is far stronger than provided deflected at the guide roller 122 (not drawn case).

p0060The sensor 135 is, for example, an inductive proximity sensor with integrated preamplifier detects this position change, and immediately to the control circuit (s. <figref idrefs="f0004">Fig. 4</figref> or <figref idrefs="f0005">5</figref>) Passes, which can correct the device or machine immediately. The sensor 135 thus monitors the optimum position during the downward movement of the cutting wire 140th

p0061As sensors for the detection of analog signals are both inductive sensors without external power supply as well as sensors with external power supply. By former sensors signal amplitudes are produced by only a few 100 mV. To increase the noise immunity, ie increasing the signal disturbance-which signal should be strengthened. Suitable enhancers include differential amplifiers, electrometer amplifiers, instrumentation amplifiers. The use of a bandpass filter with simultaneous signal intensification is advantageous.

p0062Sensors with external power supply and integrated signal amplification have signal amplitudes of several volts. This means higher noise immunity. The filtering of the signals is as described before. For the evaluation, fast signal changes z. B. sensors with a signal processing frequency of several KHz used.

p0063The in <figref idrefs="f0006">Figures 6a), 6b</figref>) and <figref idrefs="f0007">7</figref> Arrangement shown can thus achieve a reliable monitoring of the wear on the Umlenkzylinderrolle 124th

p0064In the <figref idrefs="f0006">FIG. 6a), 6b</figref>) and <figref idrefs="f0007">7</figref> Arrangement shown also allows 122 to monitor the wear of the guide roller, as in the case of wear of the cutting wire 140 cuts deeper into the role and the actual position P # of sheath wire characterized in contrast to the case described above is permanently lower than the target position P0.

p0065To the roll wear to the other rollers, such as the deflection rollers 120, 121 or 121 * detect, the assembly may according <figref idrefs="f0008">figure 8</figref> be used.

p0066For this purpose, a sensor * * 135 is mounted in the vicinity of the guide roller 121, which detects the position of the cutting wire 140th Occurs at the role 121 * with time, wear on, so this manifests itself in particular in that the cutting wire 140 eats in the roll media into it. This occurs particularly in roles that have a high slip the wire, such as drive rollers or decelerating rollers. The material abrasion and burying the wire 140, the effective diameter of the roll is reduced 121 *. The wire 140 is then in a position that is considerably lower than the normal position and is especially critical when two not lie along the wire path successive pulleys in a plane but their axes are inclined towards each other in order to give the wire path complex contours. The service life of a deflecting roller is, depending on specific process parameters between 10 and 50 hours average time. If, during the wear control currently visually and manually run the critical wear a pulley overlooked, this can lead to chipping of the wire from the roll during the cutting and the other to crack the wire.

p0067By the sensor 135 * a change in position of the wire 140 is detected also in this case. Both in the example shown here by<figref idrefs="f0008">Fig. 8</figref> as well as in the example of <figref idrefs="f0007">Fig. 7</figref> the position of the wire changes transversely to its longitudinal axis. The position of the wire in the longitudinal direction of changes in the present examples (<figref idrefs="f0006 f0007 f0008">FIGS. 6-8</figref>) Not because one can assume invariance of the geometric relationships to the natural movement of the wire along its axis.

p0068With the help of the described invention and the wire tension of the cutting wire are detected and / or can be monitored. For this purpose, mounted in the immediate vicinity of the wire 140 at one or more points in each case a sensor which is preferably designed as an inductive sensor, the minimum transverse vibrations of the wire can be measured, provided that the wire for vibration is excited (mechanical and / or electromagnetic).

p0069For example, carried an electromagnetic excitation by excitation of repeating in a certain time interval short term work pulse or by a "tunable" sine frequency (wobbling).

p0070The current tension of the wire can then be given the given parameter wire diameter, wire density and unsupported length between two deflection or guide points determine. Significantly this is particularly for wire sections between the outlet from the sawed object and in wire moving direction following wire guide roller, since that is where the real tension of the wire is very undefined, due not exactly predictable friction force of the wire in sawn object on the one hand and not exactly predictable Zugspanungsübertragung through the wire guide roller on the other hand.

p0071The optimum tension corresponds to a specific vibration frequency that can be detected by the sensor accurately. A too low tension leads to a lower frequency; too high a tensile stress to a higher frequency. In order to evaluate the signals generated by the sensor, a control circuit connected to the sensors is provided. In contrast to the digital signal processing (see<figref idrefs="f0004">Fig. 4</figref> and <figref idrefs="f0005">5</figref>), As is necessary for detecting a wire jump, the analysis of analog signals is needed to determine the wire tension.

p0072In general, the exploited for various monitoring tasks sensor signals such. B<ul><li>Detection of wire jumps from a predetermined groove out</li><li>Detection of changes in position of the wire on a wire guiding element</li><li>Detecting the wear of a wire guide element</li><li>Detection of wire tension</li></ul>

p0073Utilized to the sawing process to stop immediately in the event that at least one of the sensors indicates that changing the position of the cutting wire on a wire guide plate, the sawing process through to the end and to change worn wire guide members before the start of a new sawing or only the detection result under register of process parameters monitoring of the wire saw device and evaluate.

p0074The sensor can also be implemented in one or more sensor means to be mounted on the wire saw apparatus.

LIST OF REFERENCE NUMBERS

p0075<dl id="dl0003" compact="compact"><dt>100</dt><dd>The wire saw device (Squarer)</dd><dt>110</dt><dd>Wire guiding element in the form of a wire guide plate (arrangement of multiple wire guide wheels on an axle forming a wire guide roller)</dd><dt>R1 to R10</dt><dd>Grooves in wire guide pulley</dd></dl><dl id="dl0004" compact="compact"><dt>120</dt><dd>Wire guide elements in the form of a pulley</dd><dt>121.121 *</dt><dd>Wire guide elements in the form of pulleys</dd><dt>122</dt><dd>called wire guiding element in the form of a leading pulley, also leadership</dd><dt>124</dt><dd>called wire guiding element in the form of a cylindrical pulley, also Umlenkzylinderrolle</dd><dt>125</dt><dd>Wire supply reel</dd><dt>130</dt><dd>Holder for wire guide wheels</dd><dt>135, 135 *</dt><dd>Sensor (mounted on bracket)</dd><dt>140</dt><dd>cutting wire</dd><dt>145</dt><dd>wire field</dd></dl><dl id="dl0005" compact="compact"><dt>Z</dt><dd>Pulling direction of the cutting wire</dd><dt>V</dt><dd>wear groove</dd><dt>P0</dt><dd>optimum position (target) for the cutting wire</dd><dt>P #</dt><dd>malposition</dd></dl><dl id="dl0006" compact="compact"><dt>150, 160</dt><dd>Control circuit (different versions)</dd></dl><dl id="dl0007" compact="compact"><dt>200</dt><dd>Body of crystalline material, such as bars or ingots</dd></dl>