Characterization of saw band of band sawing machine

Abstract

The patent application describes a measuring device for characterizing a saw band (11) of a band sawing machine. According to one embodiment, the measuring device comprises: a first inductive distance sensor (30) configured to generate a sensor signal representative of a distance between a sensor position and a front side of a saw band (11) on which saw teeth (101, 102) are located; a support roller (32), and a pre-tensioning mechanism configured to press the roller against the rear side of the saw band (11).

Description

Technical Field

[0001] In particular, the present invention relates to a concept for characterizing a saw band of a band saw machine. Background Art

[0002] Various band saw machines are known. In industrial environments, band saw machines with Computerized Numerical Control (CNC) are commonly used. To properly control the sawing process, the machine controller requires various parameters, which, in many machines, must be manually entered by the operator. To this end, the machine controller includes a suitable Human-Machine Interface (HMI).

[0003] The above parameters particularly concern the saw band, as its characteristics have a direct impact on the sawing process. For example, when positioning the workpiece (e.g., automatically or semi-automatically), the width of the cutting path must be taken into account. This, in turn, depends on the geometry of the saw band and, in the case of known machines, must be manually input into the machine controller. Furthermore, the permissible cutting speed (as well as the band speed and / or feed rate) may depend on the type of saw band, for example, on any restrictions on the saw band teeth or the material of the teeth (e.g., high-speed steel or carbide). Depending on the type of machine, these parameters must also be communicated to the machine controller.

[0004] As mentioned above, although the sawing process itself is automated, proper process control depends on parameters manually entered into the machine controller by the operator, which is a source of error. Several concepts exist when configuring the machine controller to help avoid these errors. For example, the saw blade can be physically marked with a barcode, QR code, RFID tag, or similar device. This marking / coding can be automatically read by a suitable reader (optical in the case of a barcode or QR code, or electromagnetic in the case of an RFID tag). It represents a numerical code, and the relevant parameters for the machine controller can be stored in a database. This concept of marking saw blades presents the problem that different manufacturers use different systems for marking saw blades, leading to compatibility issues when using saw blades from different manufacturers. Furthermore, while marking saw blades with barcodes, QR codes, RFID tags, etc. does allow for identification of the saw blade, it does not allow for the determination of the saw blade's wear state, which can also be a parameter relevant to the machine controller. Furthermore, markings, such as barcodes laser-engraved on the saw blade, are problematic because they can become unreadable due to wear during use. Of course, the markings only indicate the properties of a new saw blade.

[0005] The object of the present invention is to improve the above-mentioned situation and to develop an improved concept for the automatic characterization of saw bands. Summary of the Invention

[0006] The above-mentioned objects are achieved by a measuring device according to claim 1 and a system according to claim 12. Various embodiments and improvements are subject of the dependent claims. In the following, a measuring device for characterizing a saw band of a band saw machine is described. According to one embodiment, the measuring device comprises: a first inductive distance sensor, which is configured to generate a sensor signal, which represents the distance between the sensor position and the front side of the saw band, where the saw teeth are located; a support roller, and a pretensioning mechanism, which is configured to press the roller against the rear side of the saw band.

[0007] Another embodiment relates to a system comprising a band saw machine having a saw band and a machine controller configured to control operation of the band saw using one or more saw band parameters stored in the machine controller. The system further comprises a measuring device configured to determine at least one parameter value characterizing the saw band, wherein the machine controller is further configured to receive the parameter value determined by the measuring device and store it as a saw band parameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention will now be explained in more detail with reference to the examples shown in the accompanying drawings. The drawings are not necessarily true to scale, and the present invention is not limited to the aspects shown. Rather, they are provided to illustrate the basic principles of the invention. The following is a brief description of the drawings:

[0009] Figure 1 An example of a CNC band saw machine known per se is schematically shown.

[0010] Figure 2 is an exemplary illustration of a band saw blade having broken teeth.

[0011] Figure 3 An example of a measuring device for the automatic detection of defective saw teeth by means of an inductive distance sensor or proximity sensor is shown by means of a schematic diagram.

[0012] Figure 4 yes Figure 3 Cross-sectional view of .

[0013] Figure 5 Possible geometric shapes of the saw teeth (Fig. (a)) and different types of restriction of the saw teeth (Figs. (b) and (c)) are shown by way of example.

[0014] Figure 6 It is shown as an example Figure 3 and Figure 4 Modification of the measuring device.

[0015] Figure 7 An example is shown from Figure 4 Signal curve of the sensor signal of the inductive sensor and detection of a broken or worn sawtooth based on the signal (Figure (a)), as well as Figure 6 Signal curve of the additional sensor signal of the inductive sensor (Figure (b)) and detection of the tooth type based on this signal.

[0016] Figure 8 A further measuring device for measuring the cutting channel width of a saw band by means of a capacitive sensor is shown.

[0017] Figure 9 Shows the Figure 3 、 4 An example of integrating the measuring device of and 6 into a sensor device.

[0018] Figure 10 It shows that according to Figure 9 Block diagram of the coupling of a sensor device with the machine controller of a band saw.

[0019] Figure 11 Shows the Figure 3 、 4 Another example of integrating the measuring device of and 6 into a sensor device.

[0020] Figure 12 The flowchart shows the Figure 10 Examples of methods performed by the system. DETAILED DESCRIPTION

[0021] Before explaining various embodiments in more detail, we first Figure 1 The general structure of a band saw is briefly shown. It should be understood that the embodiments described herein can be used with different types of band saws and their application is not limited to Figure 1 The type of band saw shown in .

[0022] like Figure 1 As shown, a band saw 1 comprises a saw frame (housing) and two impellers 10a and 10b mounted thereon, one of which is driven by an electric motor. A saw band 11 is held and guided by the impeller (similar to a belt). A driven impeller also drives the saw band (at an adjustable speed). The other impeller also rotates in parallel. Figure 1 Also shown schematically is a workpiece 30 being cut by means of the saw band 11. In the example shown, the section plane is vertical. However, there are also band saws with horizontal or inclined cutting planes.

[0023] Reference numerals 20 and 21 indicate locations on the saw frame (housing) of the band saw 1 where measuring devices can be arranged, as will be described in more detail below. Mounting measuring devices at these locations is not absolutely necessary, but is advisable in most applications because these locations are relatively well protected from cooling lubricant (KSS), contaminants, swarf, dust, and other interfering factors compared to the impeller.

[0024] The machine controller may be arranged in a separate housing and Figure 1 The machine controller can be implemented in an industrial PC by software, for example. Various types of machine controllers are known per se, so these will not be discussed in more detail here.

[0025] Figure 2 An example of a saw band 11 with a plurality of teeth 101 is shown. The distance between two adjacent teeth is called the pitch p. Variable tooth pitch has proven useful when sawing metal materials in high-performance industrial production. This is usually expressed in teeth per inch. Figure 2 In the example shown, the saw teeth 102 are broken. For example, if the process parameters of the sawing process (such as cutting speed or feed rate) are set incorrectly, the saw teeth may break. Due to wear, the saw teeth may also be worn to the point where the height of the teeth is significantly lower than the height of unworn teeth.

[0026] The embodiments described here relate to a concept for characterizing saw bands (band saw blades), wherein, in particular, the wear state of the saw band is to be determined, and for this purpose, defective (broken) teeth are to be automatically detected. Some embodiments also allow for detecting the limits of the saw band and / or measuring the actual width of the cutting path. In particular, the wear state cannot be determined using known methods, such as the aforementioned markings using QR codes or the like.

[0027] Figure 3 A simplified example of a measuring device for detecting worn (broken) saw teeth using an inductive sensor is shown. Inductive sensors have proven to be particularly reliable (especially compared to optical sensor principles). Suitable sensors are commercially available as inductive position sensors or proximity sensors. Figure 3 , the inductive sensor 30 is located in the band plane A of the saw band (see also Figure 4 ) and monitors the tooth side (narrow side) of the saw band on which the teeth are arranged. The measuring direction of the sensor (wherein the distance between the sensor 30 and the saw band 11 is measured) extends in the band plane A at right angles to the running direction of the strip.

[0028] The distance between the sensor 30 and the sawtooth tip is Figure 3The distance d0 is the minimum distance between the sensor 30 and the saw band 11. When the sensor directly faces the tooth tip (main cutting edge) of an unworn saw tooth 101, the sensor measures the distance d0. If the gap between the two saw teeth is opposite to the sensor 30, the measured distance d will be greater (d>d0). Even if there is a defective (worn or broken) saw tooth (in Figure 3 denoted by 102 in FIG. 1 ) is opposite to the sensor 30 , the measured distance d1 will also be greater than the minimum distance d0 (d1>d0).

[0029] Inductive distance sensors alone are not sufficient to reliably detect defective saw teeth. In fact, the saw band 11 not only moves in the running or cutting direction (e.g. Figure 3 In addition to the vibrations (indicated by the arrows in the figure), oscillatory movements transverse to the direction of travel (chatter) can also occur, which prevent or at least impair reliable distance measurement or reliable detection of distance changes. These oscillations can be reduced, at least locally in the area of ​​the sensor 30, by arranging the support roller 32 on the belt ridge 103 on the side of the saw belt 11 opposite the sensor 30. The support roller 32 can be mounted on the frame structure of the sensor device so that it contacts the narrow side of the belt ridge 102. As the saw belt 11 moves, the support roller also rotates.

[0030] The bearing point of the support roller 32 can be movable, for example, and coupled to a spring in such a way that the support roller 32 presses against the belt ridge with a force F (preload). It is the preload F that is important, not the way it is generated. Figure 3 Only the preload force F is shown, without the spring. The support roller 32 can be made of metal, but in some embodiments can also be made of plastic. The running surface of the support roller 32 can also have a plastic or rubber coating. In particular, in combination with the preload force F, the support roller 32 reduces oscillatory movement of the saw band 11 transverse to the running direction of the saw band and significantly increases the reliability of detecting defective saw teeth.

[0031] Figure 4 Shown Figure 3 Cross-sectional view of an example. Cutting plane C (see Figure 3 ) is at right angles to the running direction of the saw band 11 and passes through the tip of the unworn tooth 101. Figure 4 The rotation axis B of the support roller 32 is also shown. The detection of a single broken tooth will be described in more detail below (see also for example Figure 7 ).

[0032] Figure 5 It covers all aspects of the saw blade and its tooth geometry. Figure 5Figure (a) shows an example of a special tooth geometry by means of a cross-sectional view, in which the width (thickness) of the tooth increases towards the tip. Such teeth are therefore also called trapezoidal teeth. Plane A represents the centre plane of the band saw blade. The outermost edges of the teeth (perpendicular to the centre plane A) form the main cutting edges. The edges are inclined to the left and to the right from the centre plane. The inclined parts of the cutting edges are also called secondary cutting edges. The part of the tooth 101 opposite the main cutting edge has the same thickness as the ridge 103. The main and secondary cutting edges of the tooth can be made of a different material than the ridge. For example, the cutting edge can be made of carbide or high-speed steel, while the ridge can be made of ordinary tool steel. There are saw bands with teeth of different geometries. For example, these teeth differ in the width of the main cutting edge. In Figure 5 In Figure (a), two possible modifications of the tooth geometry are shown by way of example by dashed lines. In one case, the main cutting edge extends across the entire width of the tooth. In this case, there are practically no secondary cutting edges. In a saw band, different types of teeth can follow one another. This is particularly true for unrestricted saw bands. In a saw band, groups with a specific tooth sequence can be repeated periodically (e.g., tooth 1 with a narrow main cutting edge, tooth 2 with a medium main cutting edge, tooth 3 with a wide main cutting edge).

[0033] Figure 5 Figures (b) and (c) show different types of saw teeth of a band saw blade. Figure 5 Figure (b) shows a standard limit where one of the three adjacent teeth is straight (i.e. in belt plane A), one is curved to the left and one is curved to the right (i.e. inclined relative to belt plane A). Figure 5 In FIG. 1 , the straight saw teeth are designated as 101, the saw teeth curved to the right are designated as 101', and the saw teeth curved to the left are designated as 101".

[0034] Figure 5 Figure (c) shows a left-right restriction, in which the teeth are bent alternately to the right and to the left. In this variant, there are no teeth 101 located in the band plane A. There are other types of restrictions, such as group restrictions, in which two or more consecutive teeth of each group are bent in the same direction. In a wave-shaped setting, the inclination angle of the teeth varies in a periodic manner from one tooth to the other, wherein, for example, one period may include eight teeth. Saw bands with carbide cutting edges usually have no restrictions, while bimetallic saw bands with high-speed steel cutting edges almost always have restrictions. Different types of band saw blades and different types of restrictions are known per se and will not be discussed further here.

[0035] Figure 6 Shown Figure 3 and Figure 4Example of a modification / expansion of the measuring device of , in which a second inductive position or distance sensor 31 is used to determine the type of limitation of the saw band 11 . Figure 6 The support roller 32 and the first sensor 30 are connected with Figure 3 and 4 The sensor 31 is arranged in the same manner and is described above. The sensor 31 has a measuring direction perpendicular to the band plane A. The sensor 31 thus detects the saw band 11 (in particular the teeth) from the side. The sensor signal depends on the distance a between the sensor 31 and the saw band (see Figure 6 ), wherein when the saw tooth located next to the sensor 31 is bent to the left (toward the sensor) (tooth 101"), the distance a is smaller, and when the saw tooth located next to the sensor 31 is bent to the right (away from the sensor) (tooth 101'), the distance a is slightly larger. In the case of straight teeth 101, the distance a is a value between the two.

[0036] Figure 7 Figure (a) shows an example of Figure 3 and 4 The sensor signal represents the distance d (see Figure 4 ). When the saw blade cutting speed v c When constant, the sensor signal is essentially periodic, where the period duration is p / v c And the frequency is v c / p (as mentioned above, p represents the pitch). For example, a belt speed of 1.5 m / s and a pitch of 1.5 mm result in a sensor signal frequency of 1 kHz. Each cycle can therefore be assigned to a saw tooth or its tooth tip. In the case of a variable tooth pitch, the cycle duration will also vary (e.g., fluctuate around a mean value).

[0037] from Figure 7 As can be clearly seen in Figure (a), the local minimum in each cycle represents the distance between the sensor 30 and the associated sawtooth. This can be done by evaluating the sensor signal or measurement data (see Figure 10 , data processing unit 4), for example, detects undamaged (unworn) and defective (broken) saw teeth by comparison with a threshold value. If the level of the sensor signal drops below a (predefined) threshold value within a certain period (corresponding to a certain saw tooth), the corresponding saw tooth is detected as "non-defective". If it does not fall below the threshold value, the corresponding saw tooth is detected as "defective". In this way, the number of defective saw teeth of the saw band can also be determined, thereby determining the wear state of the saw band. The number of defective saw teeth can be a quantitative measure of the wear state. In Figure 7In the example shown in FIG. (a), two thresholds are shown. The threshold labeled "tooth breakage" represents the distance d1 for detecting broken saw teeth. The threshold labeled "wear" is used to detect teeth that are partially worn (but not broken). In a particular example, several different thresholds (between d0 and d1) are used to represent different degrees of wear. In some examples, wear is directly quantitatively evaluated by the measured value (in the range between d0 and d1). Such evaluation, threshold comparison, etc. can be performed in an evaluation unit (data processing unit, see Figure 10 ).

[0038] Using the concepts described herein, not only can the number of broken saw teeth be determined, but also the degree of wear can be determined. In some embodiments, multiple thresholds can be used to detect the degree of wear. The threshold for detecting broken teeth can also depend on (for each tooth) the average value of the measured distance d0. As described above, the value d0 represents the tooth height of each saw tooth. The change in the average tooth height (compared to a new, unworn saw band) can be considered as the degree of (gradual) wear. Depending on the wear state (decrease in the average tooth height and / or the number of broken teeth), certain process parameters (such as cutting speed or feed speed) can be adjusted in the machine controller. Depending on the current wear state, the machine controller can also decide whether a new sawing process can be started with the saw band (which may also take several hours), or whether the saw band needs to be replaced.

[0039] The detection of saw band entanglement can be performed in a manner similar to the detection of broken teeth. Assume that the distance a of the straight tooth 101 to the sensor 31 is a = a0, the tooth 101' bent to the right has a distance a1 > a0, and the tooth 101'' bent to the left has a distance a2 < a0. For example, two different thresholds b1 (where a1 > b1 > a0) and b2 (where a2 < b2 < a0) can be used to distinguish between bent teeth and straight teeth. If the condition a > b1 is satisfied, the corresponding saw tooth is bent to the right. If the condition a < b2 is satisfied, the corresponding saw tooth is bent to the left. If no entanglement is detected (b2 < a < b1), then it is also very likely to be a saw band with a carbide cutting edge, because a saw band with a high-speed steel cutting edge almost always has limitations. This information can be at least sanity-checked by the machine controller. In addition, not only can it be detected whether there are limitations, but in some embodiments, it can also be detected what type of limitations exist (group limitations, standard limitations, etc., see Figure 5 ).

[0040] Figure 7 FIG. (b) shows by means of the sensor 31 (see Figure 6) detects a range of different tooth types (teeth of different geometries) of an unrestricted saw band. To this end, the sensor 31 detects the angle of the tooth from the side and can distinguish between different tooth types based on the sensor signal of the sensor 31. For a tooth with a narrow main cutting edge and a long secondary cutting edge, the sensor 31 will measure a greater distance than for a tooth with a wide main cutting edge and short (or no) secondary cutting edge. Figure 7 In the case shown in Figure (b), it is even possible to distinguish five different tooth types, the sequence of which repeats periodically. For example, several threshold values ​​can be used to distinguish between the different tooth types. In one embodiment, a measured sequence of the amplitudes of local minima (each corresponding to a tooth) is compared with patterns stored in a database and assigned to a specific saw band type. Depending on the detected tooth type, the sequence of detected tooth types, or the saw band type derived therefrom, process parameters (such as the cutting speed) can be adjusted in the machine controller.

[0041] Figure 8 Shows that it can be Figure 3 、 4 or another embodiment of a measuring device in combination with example 6. The two measuring devices can be integrated one after the other in the same sensor device / sensor unit (with respect to the running direction of the saw band). Depending on the application, Figure 6 and 8 The two measuring devices can also be installed at different positions of the band saw. Figure 8 The measuring device has at least one capacitive sensor 41 (in the example shown, there are two capacitive sensors 40 and 41). The sensors 40, 41 each have two opposing electrodes 40a, 40b (sensor 40) and 41a and 41b (sensor 41), wherein the saw belt extends between the two electrodes 41a, 41b (and 40a, 40b).

[0042] The mode of operation of a capacitive sensor for measuring the thickness of a conductive material arranged between two electrodes (e.g., 41a and 41b) associated with each other is known per se and will not be explained in further detail here. Sensor 40 is used to measure the thickness of the saw blade in the region of the ridge, while sensor 41 is used to measure the thickness of the saw blade in the region of the secondary cutting edge of the saw teeth. Thus, the width t1 of the cutting path can be automatically determined based on the sensor signal of capacitive sensor 41.

[0043] Figure 9 It is shown as an example that Figure 3 and 4 The possibility of integrating the measuring device of the present invention into a sensor device (sensor module) which can be mounted on a saw frame (housing of the saw machine 1 ), for example. Figure 9The sensor device comprises a frame 50 having a mounting surface 55 on which the device can be mounted on the saw machine 1 in the vicinity of the saw band (see Figure 1 , mounting locations 20 and 21). Frame 50 can be any carrier element, structure of multiple carrier elements, or part of a housing. It is used to support or suspend various other components of the sensor device. Frame 50 has one or more linear guides, on which support roller 32 and sensors 30 and 31 are movably mounted (support point 51).

[0044] The positions of the sensors 30 and 31 are fixed after the initial adjustment. In contrast, the support roller 32 is mounted so as to be movable against the spring force of the spring 52. The spring 52 presses the support roller 32 against the ridge of the saw band (see Figure 3 and Figure 4 ). It should be understood that Figure 9 This is just one example, the actual design of the sensor arrangement will depend to a large extent on the conditions in the respective bandsaw machine.

[0045] Figure 10 It shows that according to Figure 9 The entire system comprises a sensor device with a saw band 11 (see Figure 1 ) and a measuring device (sensor unit or sensor module 3) integrated into the band saw, as well as a data processing unit 4 and the above-mentioned machine controller 2. The machine controller 2 is configured to control the operation of the band saw 1 and, for this purpose, uses one or more parameters stored in the machine controller 2, which parameters in particular characterize the saw band (saw band parameters) or depend on properties of the saw band (process parameters, such as the circulation speed of the band or the feed speed of the workpiece during the sawing process). The data processing unit 4 (evaluation unit) is configured to determine at least one value of the saw band parameter and / or the value of a process parameter based on the measurement data provided by the sensor unit 3. The machine controller 2 is also configured to receive and store the parameter value (or multiple parameter values) determined by means of the measuring device, if necessary, to update already stored values, and use them as saw band parameters or process parameters.

[0046] As mentioned above, examples of saw band parameters are the number of teeth of the saw band (e.g., teeth per inch), the number of broken teeth of the saw band, the degree of wear of the teeth, a value indicating whether the saw band 11 has a restriction (optionally also the type of restriction) or a value representing the width of the cutting path and / or the sequence of tooth types detected (in the case of trapezoidal teeth) or the saw band type derived therefrom. Examples of process parameters derived from the measurement data (or the saw tooth parameters determined therefrom) are the circulation speed of the strip (which can also be zero in the case of an emergency shutdown of the band saw) and the feed speed of the workpiece, depending on the sawing process.

[0047] The data processing unit 4 receives (digital or analog) measurement data from the sensor unit 3 and is configured to process (evaluate) the sensor data in order to determine therefrom one or more saw band and / or process parameters (e.g. a set of parameters) and transmit them to the machine controller 2. The data exchange between the data processing unit 4 and the machine controller 2 can be realized by means of known technologies (e.g. bus systems for serial digital communication) and generally depends on the manufacturer of the band saw. The data processing unit 4 can thus be operated independently of the machine controller 2. Only the communication connection between the data processing unit 4 and the machine controller 2 is manufacturer-specific. In a specific example, the data processing unit 4 can be integrated into the sensor unit 3 ("smart sensor").

[0048] from Figure 10 As can be seen, the band saw, sensor unit, data processing unit, and machine controller can operate as a control loop. That is, the data processing unit 4 can actively intervene in the ongoing sawing process based on the measurement data provided by the sensor unit 3, for example by transmitting an updated parameter set to the machine controller 2, or by transmitting a command to the machine controller that, for example, results in a change in saw band or process parameters (during ongoing operation) or an emergency shutdown of the band saw. Furthermore, the measurement results or parameters derived therefrom can be visualized via the HMI of the machine controller 2. The HMI also allows the operator to manually intervene in the sawing process.

[0049] The data processing unit 4 also allows (optional) vertical integration into the automation network (see Figure 10 The system data can thus be used to optimize processes at the process management level (e.g. Supervisory Control and Data Acquisition, SCADA, systems). Cloud connectivity is also possible. Due to the system architecture (data processing unit 2 is separated from machine controller 2), machines with older controller generations can also be integrated into the automation network.

[0050] The data processing unit 4 may comprise a processor and a memory for storing software instructions which, when executed by the processor, enable the data processing unit 4 to perform the functions described herein for evaluating the sensor signals / measurement data. To this end, the data processing unit 4 specifies peripheral devices (e.g., communication interfaces, analog-to-digital converters, etc.) for connection to the sensor unit 3 and the machine controller 4. The data processing unit 4 may be, for example, a personal computer (PC), an industrial PC, or an embedded system. Parts of the data processing unit 4 may also be implemented by electronic safety circuits (hardware) that do not require software to operate. The data processing unit 4 is understood to be any entity comprising hardware and software that is suitable for providing the functions described herein (e.g., evaluation of sensor signals / measurement data and, based thereon, determining one or more parameters or commands for the machine controller).

[0051] Similar to Figure 9 , Figure 11 Shows the Figure 3 、 4 Another example of integrating the measuring device of and 6 into a sensor device. Figure 11 Figure (a) shows a perspective view, and Figure (b) shows a corresponding side view. Figure 11 Figure (c) shows a device with decoupled sliding elements, which will be discussed in more detail later. Figure 11 Example with Figure 9 The essential difference of the example is that these elements serve to move the sensor device mounted on the band saw away from the saw band by a pivoting movement, so that the saw band can be changed without any problems. The axis of rotation of the pivoting movement is at Figure 11 It is indicated by "C".

[0052] In operation, the support roller 32 is supported, for example, by a spring ( Figure 11 In order to be able to pivot the sensor device (ie the housing or frame 50) away from the saw band 11, a locking mechanism is provided which enables the support roller 32 to be locked at a certain distance from the band ridge. Figure 9 As shown, in this example, the support roller 32 is also mounted on a sliding element 54, which is movably mounted along a linear guide 53 (part of the frame 50). The sliding element 54 has a stop 58, on which a latch 59 can be engaged. In the example shown, the sliding element 54 (sliding bracket) can be pushed away from the belt spine against the force of the spring until the latch 59 engages the stop 58 and locks the sliding element 54. This state is as shown in FIG. Figure 11 (c) of FIG. 5 , wherein a spring presses a stopper 58 of the sliding element 54 against a latch 59. Release of the locking mechanism can be achieved manually by actuating a lever 60, thereby tilting the latch 59 away from the stopper 59. It should be understood that the locking mechanism shown for the support roller 32 (i.e., the sliding element 54 for mounting the support roller 32) is merely an example. Other locking methods may also be used.

[0053] The sensors 30 and 31 are movably mounted on a second sliding element 54' on the linear guide. During operation, the sliding element 54' can be clamped on the linear guide. In the case shown, the clamping can be activated and released by a knob 61. When the clamping is released, the sliding element 54' can be moved so that the sensors 30 and 31 move away from the saw teeth, as shown in FIG. Figure 11 The sensor device can then be easily pivoted (about the axis of rotation C) away from the saw blade. Figure 11 In the state shown in FIG (b), the two sliding elements 54 and 54' are coupled, ie, arranged at a defined distance from each other. This distance can be predetermined, for example, by a spacer between the two sliding elements 54 and 54'.

[0054] Figure 12 The flow chart shows that Figure 10 Thus, the method comprises acquiring measurement data ( Figure 12 , step S1). The method further comprises generating a command for a machine controller of the band saw based on the measurement data ( Figure 12 , step S2), and transmits the command to the machine controller of the band saw ( Figure 12 , step S3). The command may be an update command for updating one or more saw bands or process parameters. The command may also be an emergency stop command for interrupting the sawing process.

[0055] In one example, generating a command includes determining at least one saw band parameter characterizing a property of the saw band based on the measurement data. In this case, the command is an update command for updating the saw band parameters in the machine controller. The command may also be an emergency stop command, for example when the saw band parameters indicate excessive wear of the saw band. As previously mentioned, examples of saw band parameters are wear (reduction in tooth height due to wear), width of the cutting path, total number of broken teeth, number of broken consecutive teeth, limits, etc. In the event of excessive wear, for example when a certain number of adjacent teeth are broken, an emergency stop command may be generated to interrupt the sawing process.

[0056] The generation command may also comprise determining (based on the measurement data) process parameters that influence the sawing process performed with the band saw. In this case, the command is also an update command for updating the process parameters in the machine controller (2). As mentioned above, examples of process parameters are the feed rate of the workpiece and the circulation speed of the band. These can be reduced, for example, depending on the wear of the saw band.

[0057] In particular, a command can be transmitted to the machine controller during an ongoing sawing process performed by means of the band saw in order to actively intervene in the sawing process in order to change or stop the sawing process.

Claims

1. A measuring device for characterizing a saw blade (11) of a band saw, wherein: The measuring device comprises: a first inductive distance sensor (30) configured to generate a sensor signal representing the distance between a sensor position and a front side of the saw band where the saw teeth (101, 102) are located; support rollers (32), and A pre-tensioning mechanism is configured to press the roller (32) against the rear side of the saw band (11).

2. The measuring device according to claim 1, further comprising: a frame (50) for mounting the measuring device on the band saw, wherein the first distance sensor (30) is mounted on the frame (50) such that a measuring direction of the first distance sensor (30) is located within the belt plane of the saw belt (11); wherein the support roller (32) is movably mounted on the frame (50); and The pre-tightening mechanism comprises a spring which generates a pre-tightening force between the frame (50) and the support roller (32), so that the pre-tightening force presses the support roller (32) against the rear side of the saw band (11).

3. The measuring device according to claim 1 or 2, further comprising: An evaluation device is configured to detect, based on the sensor signal and for each saw tooth (101, 102) of the saw band (11), whether the height of the respective saw tooth (101, 102) is below a threshold value.

4. The measuring device according to claim 3, in, The evaluation device is configured to evaluate a saw tooth (102) as a defect when the height of the corresponding saw tooth (102) is lower than the threshold value.

5. The measuring device according to claim 3 or 4, in, The evaluation device is configured to count the saw teeth (102) of the saw band (11) that are evaluated as defective; and / or Therein, the evaluation device is configured to determine a value representing the number of saw teeth (101, 102) per unit length.

6. The measuring device according to any one of claims 3 to 5, in, The evaluation device is configured to determine a value representing a degree of wear of the saw band.

7. The measuring device according to claim 6, in, The degree of wear of the saw blade is determined by the average value of the measured tooth heights.

8. The measuring device according to any one of claims 1 to 7, further comprising: A second inductive distance sensor (31) is configured to generate a second sensor signal indicating whether the saw teeth (101, 102) are located in the band plane of the saw band (11) or are inclined relative to the band plane.

9. The measuring device according to any one of claims 1 to 8, further comprising: Another sensor (41) is configured to measure a value representing the width of the cutting channel (t1) of the saw band (11).

10. The measuring device according to any one of claims 1 to 9, in, The support roller (32) is mounted on a movable sliding element (54), and The measuring device includes a locking mechanism configured to lock the pre-tensioning mechanism and maintain the support roller (32) in a position spaced apart from the rear side of the saw band.

11. The measuring device according to any one of claims 1 to 10, in, The first inductive distance sensor (30) is mounted on a further movable sliding element (54'), wherein the further sliding element (54') can be fixed by a clamping mechanism.

12. A system comprising: A band saw (1) having a saw band (11) and a machine controller (2) configured to control a sawing process performed by means of the band saw (1), using for this purpose one or more saw band parameters and / or process parameters stored in the machine controller (2); a measuring device configured to determine the value of at least one parameter characterizing the saw band (11), The machine controller (2) is further configured to receive parameter values ​​determined by means of the measuring device or parameter values ​​derived therefrom and to store them as saw band parameters or process parameters.

13. The system according to claim 10, in, The at least one parameter value characterizing the saw band (11) comprises one of the following values: a value representing the number of the teeth of the saw band; A value representing the number of broken teeth of the saw band; Indicates whether the saw band (11) has a limited value; A value representing the width of the cutting channel.

14. The system according to claim 10 or 11, in, The measuring device is connected to the band saw in a pivotable manner relative to the saw band (11).

15. The system according to any one of claims 12 to 14, in, The measuring device comprises a sensor unit (3) and a data processing unit (4) integrated in the band saw (1), The sensor unit (3) provides measurement data characterizing the saw band (11), and the data processing unit (4) is configured to determine the parameter value based on the measurement data.

16. The system according to claim 15, in, The data processing unit (4) is configured to determine a process parameter related to a sawing process performed by the band saw (1) based on the parameter value.

17. The system according to claim 15 or 16, in, The data processing unit (4) is configured to update the at least one parameter based on the measurement data and transmit it to the machine controller (2).

18. The system according to claim 16, in, The data processing unit (4) is configured to update the process parameters based on the measurement data and transmit them to the machine controller (2).

19. A method comprising: Acquiring measurement data characterizing a saw band (11) of a band saw (3) by means of a sensor unit (3); generating commands for a machine controller (2) of the band saw (1) based on the measurement data; and The command is transmitted to the machine controller (2) of the band saw (1).

20. The method according to claim 19, wherein Generating the command includes: determining at least one saw band parameter characterizing the saw band (11) based on the measurement data, The command is a command for updating the at least one saw band parameter in the machine controller (2).

21. The method according to claim 19 or 20, wherein Generating the command includes: determining, based on the measurement data, process parameters that influence a sawing process performed with the band saw (11); The command is a command for updating the process parameter in the machine controller (2).

22. The method according to claim 21, in, Updating the process parameters in the machine controller leads to the termination of the sawing process.

23. The method according to any one of claims 19 to 22, in, During an ongoing sawing process performed by means of the band saw, the command is transmitted to the machine controller (2) in order to change or stop the sawing process.

24. A system comprising: Band saw (1); a machine controller (2) for the band saw (1); a sensor unit (3) integrated in the band saw for acquiring measurement data characterizing a saw band (11) of the band saw (3); as well as A data processing unit (4) is designed to carry out the method according to claim 19 by means of the sensor unit (2).

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