EP4437305A1

EP4437305A1 - Method and device for measuring a plate-shaped workpiece

Info

Publication number: EP4437305A1
Application number: EP22822436.6A
Authority: EP
Inventors: Thilo Solawa; Harald Klein
Original assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Current assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Priority date: 2021-11-25
Filing date: 2022-11-25
Publication date: 2024-10-02
Also published as: WO2023094609A1; DE102021130857A1

Abstract

The invention proposes a method for measuring a plate-shaped workpiece (2), having the following method steps: A) conveying the workpiece (2) along a conveying axis (7) through a measuring region (8) of a measuring device (9) having a plurality of contactless measuring sensors (10', 10'', 11', 11'', 12', 12'', 13', 13'') which are each in the form of line sensors and are configured to each sense at least one edge point of the workpiece (2) in a spatially resolved manner within the measuring region (8); B) detecting a measurement position of the workpiece (2) by detecting a rear edge (4) and/or a front edge (3) of the workpiece (2) in an inflow region (14) and/or in an outflow region (15) of the measuring region (8); C) outputting at least one trigger signal to the measuring device (9) as soon as the measurement position of the workpiece (2) is detected; D) measuring the edges of the workpiece (2) by means of the measuring sensors (10', 10'', 11', 11'', 12', 12'', 13', 13'') of the measuring device (9), wherein at least two of the measuring sensors (10', 10'', 11', 11'', 12', 12'', 13', 13'') are triggered at the same time on the basis of the trigger signal in order to determine at least two edge points of the workpiece (2), preferably two edge points for each workpiece edge, within the measuring region (8) in a spatially resolved manner; E) determining at least one parameter of a workpiece geometry and/or of a workpiece position within the measuring region (8) on the basis of the sensed edge points. The invention also relates to a measuring device (9) for measuring a plate-shaped workpiece (2).

Description

Method and device for measuring a plate-shaped workpiece

The invention relates to a method for measuring a panel-shaped workpiece and a measuring device for measuring a panel-shaped workpiece.

In the industrial processing of panel-shaped workpieces, in particular wood-based panels, these are usually processed in such a way that at least one or more straight workpiece edges are produced. The dimensions of the workpiece and its geometry depend largely on the course of these workpiece edges. So that the workpiece can be further processed in an economical manner or, for example, prepared for delivery, it is advantageous to ensure that the workpiece has the required quality with regard to its geometry and dimensions. By identifying any quality deviations, qualitatively inferior workpieces can be protected from additional, cost-intensive processing steps and ejected from the production process as rejects immediately after quality assurance.

In the industrial production of panel-shaped workpieces, in particular panel-shaped workpieces made from a wood-based material, there is a need to ensure the required quality of the workpiece not in stationary measuring stations but during a conveying movement.

It is the object of the invention to propose a method and a device with which the geometry and the dimensions of a plate-shaped workpiece can be determined simply and reliably during its conveying movement.

The object is achieved by means of a method according to claim 1. The object is also achieved by means of a measuring device according to claim 16. Advantageous developments are the subject matter of the dependent subclaims. The method according to the invention for measuring a plate-shaped workpiece comprises the following method steps:

A) conveying the workpiece along a conveying axis through a measuring range of a measuring device with a plurality of non-contact measuring sensors, which are each designed as line sensors and are designed to detect an edge point of the workpiece with spatial resolution within the measuring range;

B) detecting a measurement position of the workpiece by detecting a rear edge and/or a front edge of the workpiece in an entry area and/or in an exit area of the measurement area;

C) outputting at least one trigger signal to the measuring device as soon as the measuring position of the workpiece is detected;

D) Measuring edges of the workpiece using the plurality of measuring sensors, with at least two of the measuring sensors being triggered simultaneously as a function of the trigger signal in order to determine at least two edge points of the workpiece, preferably two edge points for each workpiece edge, within the measuring range with spatial resolution;

E) Determining at least one parameter of a workpiece geometry and/or a workpiece dimension as a function of the detected edge points.

The conveying movement of the workpiece preferably takes place by means of a conveying device on which the workpiece rests and is conveyed through the measuring area of the measuring device. In particular, the conveying movement can take place by means of a conveyor belt, a roller conveyor or a belt conveyor. With regard to the conveying movement of the workpiece, the workpiece has a leading front edge, a trailing rear edge and two side edges.

The measuring range represents a spatial area within which a quality-relevant workpiece edge can be detected in a spatially resolved manner. A spatially resolved detection includes the determination of at least one spatial coordinate of a quality-relevant workpiece edge within the measuring range. In a simple embodiment of the method, a determined edge point corresponds to a coordinate tuple that describes the two-dimensional position of the detected edge point in the measurement area. In connection with the invention described here, the term workpiece edge can be understood as a workpiece edge which delimits the spatial extension of the workpiece in plan view. In particular, the workpiece edge is not identical to a corner point of the workpiece.

It is essential for the method according to the invention that the measuring area has an inlet area and an outlet area. The inlet area and the outlet area represent spatial sub-areas of the measuring area and are designed in such a way that the workpiece with its front and rear edge first traverses the inlet area and then the outlet area as a result of the conveying movement.

In order to carry out an edge measurement for quality assurance purposes, the measuring sensors of the measuring device are triggered in an event-dependent manner as soon as the workpiece reaches a measuring position. The event-dependent control of the measuring sensors ensures that the edge measurement is only carried out when at least one quality-relevant workpiece edge, preferably a plurality of quality-relevant workpiece edges, in particular all quality-relevant workpiece edges, is or is within the measuring range. For this purpose, the measuring area has dimensions that are adapted to the dimensions of the workpiece in such a way that the quality-relevant workpiece edge to be measured is located within the measuring area with a sufficiently high probability when the measuring position is detected and at least two of the measuring sensors detect two edge points of this workpiece edge. The workpiece edge that is relevant to quality can be any edge of the workpiece, in particular the front edge, the rear edge or one of the two side edges.

According to the invention, the measuring sensors, by means of which the method is carried out, are each designed as line sensors. For this purpose, the measuring sensors preferably each have a measuring axis along which a workpiece edge can be detected. When the measuring sensors are triggered, they record at least one point along their respective measuring axis, which can be assigned to at least one detected workpiece edge. The edge point thus detected can preferably depend on the position and/or orientation of the respective measuring sensor and in particular its Measuring axis are used for determining a position of the edge point in the measuring range.

In this case, the line sensors can be designed as laser light section sensors or line sensors or as line CCD sensors. The line sensors are associated with a smaller installation space, especially in comparison to cameras, and are less susceptible to faults.

In a conceivable embodiment, to which the invention is not limited, however, the measuring sensors are designed in such a way that they can preferably only be used to detect exactly one point on a workpiece edge. In another optional embodiment, it is also possible to detect two points of two adjacent workpiece edges, for example in the area of a corner.

In a further embodiment, the measurement sensors are each designed in one piece or in one piece and preferably have an integrated light source, by means of which it is possible to create lighting conditions that promote reliable edge measurement. It is also within the scope of the invention that a light source is designed separately from the measuring sensor in order to create the lighting conditions. The measurement sensors are preferably designed in such a way that no additional light source is required.

It is a finding on which the invention is based that the front edge and/or the rear edge during the conveying movement can be used in a simple manner to detect whether the workpiece has reached the desired measuring position. This is related to the fact that the presence of the leading edge or the trailing edge in the lead-in area or in the lead-out area allows a simple conclusion to be drawn as to the area in which the rest of the workpiece is located. Within the scope of the invention, there are different possible measurement positions for the workpiece, which can be recognized individually or in combination with one another in the method according to the invention in order to trigger the edge measurement.

In a first possible measuring position, the leading edge of the workpiece is within the entry area. Upon detection of A trigger signal can be output to at least two measuring sensors at the leading edge within the lead-in area in order to carry out an edge measurement at the leading edge in the lead-in area. In this example, the detection of the leading edge can be used to trigger two measurement sensors. At the same time, the front edge represents a quality-relevant workpiece edge, for which two edge points are recorded in order to use them to deduce the position of the workpiece.

A second possible measuring position is preferably reached when the leading edge of the workpiece is within the run-out area. It is advantageous here if the remaining, trailing area of the workpiece is located within the measuring area with at least one quality-relevant workpiece edge, which preferably does not correspond to the detected front edge. When the leading edge is detected in the run-out area, the trigger signal can be output to at least two measurement sensors in order to carry out an edge measurement within the measurement area and preferably outside the run-out area. It is also within the scope of the invention that the edge measurement is carried out at the second measurement position within the run-out area.

A third possible measurement position is preferably reached when the trailing rear edge of the workpiece is within the entry area. It is advantageous here if the remaining, leading area of the workpiece is located within the measuring area with at least one quality-relevant workpiece edge, which preferably does not correspond to the recognized rear edge. When the trailing edge is detected in the lead-in area, the trigger signal is output to at least two measurement sensors in order to simultaneously carry out an edge measurement within the measurement area and preferably outside the lead-in area. It is also within the scope of the invention that the edge measurement is carried out at the third measurement position within the lead-in area.

In a fourth possible measuring position, the workpiece is located with its trailing rear edge within the run-out area. When the trailing edge is detected in the run-out area, the trigger signal is sent to at least two Measurement sensors issued to perform an edge measurement on the workpiece. In particular, it is conceivable that the detection of the fourth measurement position serves to trigger at least two measurement sensors in the run-out area in order to carry out an edge measurement on the trailing edge within the run-out area. In this example, the detection of the trailing edge can be used to trigger two measurement sensors. At the same time, the rear edge represents a quality-relevant workpiece edge, for which two edge points are recorded in order to use them to ensure the quality of the workpiece. Alternatively, further measurement sensors can be triggered in order to measure other workpiece edges that are also located in the run-out area.

Irrespective of which of the measurement positions described above is used to carry out the method, it is essential that in method step D) at least two measurement sensors are triggered simultaneously to carry out the spatially resolved edge measurement. This makes it possible to simultaneously detect two edge points of the workpiece, in particular two edge points of a connected workpiece edge. Compared to a measurement in which two edge points are measured offset in time during the conveying movement of the workpiece, there is the advantage that the conveying speed of the workpiece does not have to be taken into account in principle in order to be able to map the measured edge points within a common coordinate system. Two, four, six or eight measuring sensors are preferably provided, which can each be controlled by only one trigger signal in order to measure two or four or six or eight edge points simultaneously.

As a result of the edge measurement in method step D), the previously triggered measurement sensors each output a position of an edge point within the measurement area. Using a computing or evaluation unit, the edge points can be evaluated as a function of the positions and/or orientations of the measuring sensors within a common coordinate system in order to determine one or more parameters of the workpiece geometry in method step E). It is within the scope of the invention that the measured edge points are evaluated in such a way that the workpiece geometry and/or the workpiece position within the measuring range is inferred can be. For this purpose, the measured edge points can be interpolated and/or extrapolated in a simple manner in order to be able to infer at least an edge profile of the workpiece. Since the workpiece edges are straight in their respective nominal state, it is sufficient for the quality assessment if the measured edge points, if they belong to a common workpiece edge, are connected by a straight line whose course corresponds to that of the measured workpiece edge.

The invention is not limited to the manner in which the leading edge or the trailing edge is detected in the lead-in area or in the lead-out area. Preferably, at least one of the measuring sensors and/or an additional trigger sensor, which is designed as a light barrier, for example, is designed to detect the presence of the leading edge and/or the trailing edge in the entry area and/or in the exit area and in method step C) a trigger signal output to the measuring device. In particular, the front or rear edge is detected depending on whether a rising or falling edge flank is detected during the conveying movement of the workpiece within the entry area or within the exit area.

If one of the measurement sensors is used both to carry out an edge measurement and to detect at least the leading or trailing edge, it preferably has two operating modes. In a first operating mode, the measurement sensor can receive a trigger signal, for example a binary control voltage, from another measurement sensor or an additional trigger sensor in order to carry out an edge measurement on a workpiece edge as a function thereof. In a second operating mode, the measuring sensor itself can output the trigger signal, in particular a control voltage, to the measuring device or directly to another measuring sensor as soon as a rising or falling edge flank is in the lead-in area or in the lead-out area and is detected by the measuring sensor.

It is within the scope of the invention that at least method step D) is carried out multiple times, so that edge points of the workpiece are measured multiple times in order to statistically secure the measurement result. In an advantageous development, the workpiece is conveyed at least in method step A) by means of a conveying device along the conveying axis, with the workpiece protruding at least in the measuring area with at least one workpiece edge to be measured over the conveying device and with the measuring sensors being arranged below the conveying device.

According to the development described above, it is possible to increase the accuracy of the edge measurement. In this context, investigations by the applicant have shown that that side of the workpiece on which it rests while the method is being carried out is generally flat and has a substantially constant height profile, particularly in the region of its workpiece edges. This favors the detection of the workpiece edges and the edge measurement. By arranging the workpiece in which the workpiece edges protrude over the conveyor device, the workpiece edges can thus be measured by the measuring sensors, which are arranged below the workpiece, with a low measurement uncertainty or with low measurement deviations.

The conveyor device is preferably divided into a number of segments, with the workpiece in the measuring area protruding over the conveyor device and/or over a segment with at least one workpiece edge to be measured between two segments. In particular, the segments of the conveying device can be spaced apart from one another at least in regions along and/or transversely to the conveying axis. During its conveying movement, the workpiece can be located at least at times with its front edge and/or its rear edge and/or one of its side edges between two segments and can be measured by means of at least two measuring sensors. The at least two measuring sensors are preferably located below the conveyor device and between the segments of the conveyor device.

It is also within the scope of the advantageous development that the conveyor device is uninterrupted along the conveyor axis and has a width transverse to the conveyor axis that is less than the width of the workpiece, so that the front edge and/or the rear edge and/or one of the side edges of the workpiece, viewed in the direction transverse to the conveying axis, protrude over the conveying device. In an advantageous development, two trailing edge points of the trailing edge are simultaneously measured in a spatially resolved manner in method step D) in the run-in area by means of at least two measuring sensors. In method step E), a course of the rear edge of the workpiece within the measuring range is preferably determined using the two rear edge points.

According to the development described above, the workpiece is preferably in the second or in the third possible measuring position and with its rear edge in the entry area. The trigger signal can thus be output both upon detection of the front edge in the exit area and after detection of the rear edge in the entry area in order to measure at least two rear edge points of the workpiece in the entry area with spatial resolution.

To determine the course of the trailing edge, the two measured trailing edge points can be connected in a simple manner by means of a straight line whose course within the measuring range corresponds to the course of the trailing edge of the workpiece.

In an advantageous development, two front edge points of the front edge are simultaneously measured in a spatially resolved manner in method step D) in the outlet area by means of at least two measuring sensors. In method step E), a course of the front edge of the workpiece within the measuring range is preferably determined using the two front edge points.

According to the development described above, the workpiece is preferably in the second or in the third measuring position and with its front edge in the run-out area. The trigger signal can thus be output both after detection of the front edge in the exit area and after detection of the rear edge in the entry area in order to measure at least two front edge points of the workpiece in the exit area with spatial resolution. To determine the course of the front edge, the two measured points on the front edge can be connected in a simple manner by means of a straight line, the course of which corresponds to the course of the front edge of the workpiece within the measuring range

In an advantageous development, the measuring area comprises at least one side area, through which the workpiece is conveyed with a side edge in method step A) and in method step D) at least one side edge point is detected in the side area depending on the trigger signal by means of at least one measuring sensor.

The advantageous development of the method described above is based on the knowledge that, in addition to the detection of two front edge points and/or two rear edge points, it is also advantageous to detect a side edge point in order to ensure the quality of the workpiece. With just one side edge point, it is only possible under certain circumstances to determine a side edge course within the measuring range. However, it is within the scope of the advantageous development that the workpiece is aligned with its side edge points during the conveying movement along the conveying axis. Quality assurance can therefore be carried out on the side edge simply by determining just one side edge point within the measurement area and using it to infer the position of the side edge within the measurement area. If the measured side edge point is not in a target position within the measuring range or within a tolerance range, it can be concluded that the workpiece does not have the required width or is not positioned in the required manner.

The measurement area preferably includes two side areas and the workpiece includes two side edges, with the workpiece being conveyed in method step A) with a first side edge through a first of the two side areas and with a second side edge through a second of the two side areas. In method step D), at least one side edge point of the first side edge is preferably detected in the first side area by means of at least one measuring sensor, and at least one side edge point of the second side edge is preferably detected in the second side area by means of at least one other measuring sensor. In an advantageous development, in method step D) two side edge points of a side edge are detected simultaneously in the side area depending on the trigger signal by means of two measuring sensors and in method step E) a side edge course of the side edge within the measuring area is determined with the two side edge points.

According to the development described above, it is easily possible to determine the course of a side edge by simultaneously measuring two side edge points. This is particularly advantageous if the workpiece is not aligned with the measured side edge in a known or known orientation within the measuring range. In addition, it can preferably be sufficient to determine the course of the side edge of only one side edge if the width of the workpiece is known or assumed to be known and the side edges of the workpiece run parallel to one another.

In method step D), at least two side edge points of the first side edge are preferably detected in the first of two side areas by means of at least two measuring sensors and at least two side edge points of the second side edge are detected in the second side area by means of at least two other measuring sensors. In method step E), a side edge profile of the first side edge within the measurement area is preferably determined with the two side edge points of the first side edge and a side edge profile of the second side edge within the measurement area is determined with the two side edge points of the second side edge. In this way, the workpiece geometry and the workpiece dimensions can be determined using the curves of both side edges and the front edge and/or rear edge.

The measuring device for carrying out the method preferably has a total of eight measuring sensors, with two measuring sensors being designed and arranged to measure two edge points within the entry area in a spatially resolved manner. Two further measurement sensors are designed and arranged to measure two edge points within the outlet area in a spatially resolved manner. Two further measuring sensors are designed and arranged to measure two edge points within the first of two side areas in a spatially resolved manner and two further measurement sensors to measure two edge points within the second side area in a spatially resolved manner. The workpiece is preferably in a measuring position in which the rear edge is within the entry area and the front edge is within the exit area, and in which the side edges are each within a side area. A total of eight edge points of the workpiece, in each case two edge points per workpiece edge, are preferably measured simultaneously by means of the eight measuring sensors.

In a further development, in method step B) during the conveying movement of the workpiece, at least two measuring positions of the workpiece are detected, with the trailing edge being detected in the entry area in method step B1) and a first trigger signal being output to the measuring device in method step C1). . In a method step B2) the leading edge is detected in the run-out area and in a method step C2) a second trigger signal is output to the measuring device. In a method step D1), depending on the first trigger signal, a side edge point of a side edge is detected by means of at least one measuring sensor in the side area, preferably in both side areas, and in a method step D2) depending on the second trigger signal in the side area by means of the same measuring sensor as a result of the conveying movement of the workpiece another side edge point of the side edge is detected and output.

According to the advantageous development described above, the workpiece is in the conveying movement during the edge measurement, while at least one measuring sensor in the side area first measures a side edge point of a side edge and then the other side edge point of the same side edge. The two measured side edge points of method steps D1) and D2) can be used in particular to check whether the workpiece is aligned with the measured side edge along the conveying direction or is inclined relative to the conveying direction, especially if the side edge points are connected by a straight line .

The measurement sensor preferably outputs a first time stamp in method step D1) and a second time stamp in method step D2). In process step E) a side edge course of the workpiece within the measuring range is determined with the two measured side edge points, a conveying speed of the workpiece and the first and the second time stamp.

Method steps D1) and D2) preferably take place in chronological succession, with method step D2) in particular taking place after method step D1). By assigning a time stamp to each of the method steps D1) and D2), together with the conveying speed of the workpiece, it is directly possible to precisely determine the course of the side edges. The conveying speed can be assumed to be known or can be measured or output by a control unit of the conveying device.

In an advantageous development, the conveying speed of the workpiece is determined by means of at least one measuring sensor in method steps D1) and/or D2). A measuring sensor in the inlet area or outlet area can preferably be used to determine the conveying speed. For this purpose, when triggered, one of the measuring sensors can, for example, carry out two edge measurements offset in time relative to one another using an edge point. As a result of the conveying movement of the workpiece, the edge point of the measuring sensor is moved through the detection range of the measuring sensor. The conveying speed can be calculated or determined in a simple manner on the basis of the displacement of the measured edge point within the detection range of the measuring sensor.

In another advantageous development, at least two measuring positions of the workpiece are also detected in method step B) during the conveying movement of the workpiece. In this case, in a method step B1) the leading edge is detected in the lead-in area and in a method step C1) a first trigger signal is output to the measuring device. In a method step B2), the trailing edge is detected in the lead-in area, and in a method step C2), a second trigger signal is output to the measuring device. In a method step D1), depending on the first trigger signal, two leading edge points of the leading edge are detected in the lead-in area by means of at least two measuring sensors. In a method step D2), two trailing edge points of the trailing edge are detected and at the same time, a leading edge point of the leading edge is detected in the run-out area by means of at least one measuring sensor.

According to the development described above, both the front and rear edge points in the lead-in area are measured one after the other. The edge points measured in this way can accordingly be assigned to the position of the leading edge and the trailing edge while carrying out method steps D1) and D2). In order to be able to draw conclusions about the geometry of the workpiece from the measured front edge points and the rear edge points, the front edge points measured in method step D1) can be relocated to the outlet area by calculation according to the conveying movement of the workpiece. In order to spatially relate the leading and trailing edge points within the measuring area and corresponding to the geometry of the workpiece measured in method steps D1) and D2), a leading edge point of the workpiece is measured in method step D2) in the run-out area. This leading edge point preferably corresponds to one of the leading edge points already measured in method step D1). In method step E), a workpiece length is preferably additionally determined as a function of a relative position between the measuring sensors used in method steps D1) and D2).

In an advantageous development of the method described above, the measuring area comprises at least one side area through which the workpiece is conveyed with a side edge in method step A), wherein in method step D1) a side edge point is measured in the side area by means of at least one measuring sensor as a function of the first trigger signal Side edge is detected and in method step D2) depending on the second trigger signal in the side area by means of at least one other measuring sensor another side edge point of the workpiece edge is detected. In method step E), a side edge profile of the workpiece edge is preferably determined using the two side edge points from method step D1) and method step D2).

According to the advantageous development described above, the workpiece is in the conveying movement during the edge measurement, while at least one measuring sensor in the side area first detects a side edge point side edge and then another measuring sensor measures the other side edge point. Method steps D1) and D2) preferably take place in chronological succession, with method step D2) in particular taking place after method step D1). The course of the side edges is preferably determined as a function of a relative position between the measuring sensors used in method steps D1) and D2).

In an advantageous development, a workpiece length and/or a workpiece width and/or a relative orientation of at least two workpiece edges and/or a position of the workpiece is determined in method step E) depending on the rear edge profile and/or the front edge profile and/or at least one side edge profile within the measuring area determined within the measuring range.

According to the advantageous development described above, the traces of the rear edge, the front edge and the side edges that can be determined are used individually or in combination with one another to determine the geometry and the dimensions of the workpiece. The workpiece length and the workpiece width can be determined between any two edge points of the rear edge and front edge or the side edges. The determination of the relative orientation of two workpiece edges can be used to evaluate parallelism between the front edge and the rear edge and/or between the side edges. Furthermore, the determination of the relative orientation of two workpiece edges can be used to evaluate a predetermined angularity between all workpiece edges.

If the determination of the edge profiles is based on two measuring steps according to the method steps D1) and D2), it is advantageous if the workpiece geometry or the workpiece dimensions are determined as a function of the relative position, in particular a distance between two measuring sensors, which occurs in the two method steps D1 ) and D2) were used. As a result, edge measurements that are offset in time can also be combined with a high level of reliability for quality assurance. In an advantageous development, at least one measuring sensor and/or the additional trigger sensor is adjusted along the conveying axis before method step A) in order to adapt a longitudinal dimension of the measuring area to an expected workpiece length. Additionally or alternatively, at least one measuring sensor can be adjusted orthogonally to the conveying axis and depending on an expected workpiece width, in order to adapt a transverse dimension of the measuring area to an expected workpiece width. Furthermore, additionally or alternatively, at least one measuring sensor can be adjusted at an angle to the conveying axis.

It is an advantage of the development described above that the dimensions of the measuring area are not fixed, but can be adapted to different workpieces. In particular, the method can thus also be carried out on workpieces which have a high variance with regard to their length and/or width.

In an advantageous development, before carrying out method steps A) to E), in a method step 0) a zero adjustment of the measuring sensors is carried out using a measuring standard, in that method steps A) to E) are carried out with the measuring standard instead of a workpiece and the measuring sensors are dependent a comparison between at least one determined standard geometry and the actual standard geometry can be adjusted.

When carrying out measurement methods, it is unavoidable in practice that the measurement accuracy of the components used is subject to various influences, such as temperature fluctuations, mechanical shocks or the aging of their components. By carrying out method step 0), it is possible to reduce such a negative influence on the measurement result. For this purpose, the measuring standard, which in particular consists of a thermally invariant material such as Invar or Zerodur, can first be measured using a reference measuring device, for example a tactile coordinate measuring device or an optical measuring device. This determines the actual standard geometry, which includes all relevant edge points of the measurement standard. The normal geometry is then determined using method steps A) to E) and at least the edge points considered relevant to quality are measured. By comparing the actual and the determined normal geometry, it can be determined whether and to what extent the measurement results of the measuring device and the reference measuring device differ. Subsequent adjustment increases the measuring accuracy of the measuring device.

Additionally or alternatively, a distance between at least two measuring sensors of the measuring device can be determined in method step 0) using at least one reference element, which preferably extends parallel to a thermal deformation axis of the measuring device, or a distance sensor. The parameters of the workpiece geometry and/or the workpiece position are determined in method step E) as a function of the distance determined in method step 0).

As already explained, the method according to the invention or an advantageous development thereof can be carried out in environments in which high temperature fluctuations can occur. In order to reduce the influence of these temperature fluctuations on the measurement result, it is advantageous to use a reference element in order to be able to determine the distance between the measurement sensors of the measurement device with high precision and, in particular, independently of any temperature influence. For this purpose, the reference element can be designed as a thermally invariant quartz rod, which has a grid, by means of which a distance or a distance deviation between two measuring sensors can be determined quantitatively. Alternatively, a distance sensor can also be used to determine the distance between the measurement sensors. This deviation can be taken into account in different ways in method step E), for example in a computational correction when determining the workpiece geometry.

The edge points of the workpiece edges are preferably detected and a workpiece geometry or the position of a workpiece edge is determined according to a predetermined aspect, for example when the workpiece is in the first, second, third and/or fourth measuring position. Alternatively or preferably in addition, the result of a detection of edge points of a workpiece edge can be discarded depending on the detection of further measuring sensors, for example if the further measuring sensors could not detect any edge points.

The object is also achieved by the measuring device according to the invention for measuring a plate-shaped workpiece, which is preferably suitable for carrying out the method according to the invention or an advantageous development of the method. The measuring device includes a plurality of non-contact measuring sensors. The measuring sensors are each designed as line sensors and are used to carry out a spatially resolved edge measurement on a plate-shaped workpiece conveyed through the measuring area and along a conveying axis and to determine at least one edge point, in particular one edge point for each workpiece edge.

It is essential for the measuring device that the measuring area along the conveying axis comprises an infeed area and an outfeed area and at least one of the measuring sensors and/or an additional trigger sensor is arranged and designed in such a way that a rear edge occurs during a conveying movement of the workpiece within the infeed area or the outfeed area or to detect a leading edge of the workpiece. The measuring sensor and/or the trigger sensor are connected to the measuring device in terms of signal technology in order to output at least one trigger signal to the measuring device for spatially resolved edge measurement of the workpiece when the rear edge and/or the front edge is detected.

One of the measuring sensors is preferably a laser light section sensor or a line sensor or a CCD line sensor. The measuring sensors are preferably arranged below a conveyor device, in particular a conveyor belt, a roller conveyor or a belt conveyor or chain conveyors, which are each designed to convey the workpiece to be measured with the conveying movement through the measuring area. The measuring area is designed in such a way that the workpiece reaches the measuring area with at least one quality-relevant workpiece edge during its conveying movement. The quality-relevant workpiece edge can be the Act leading edge, the trailing edge or at least one of two side edges.

A number of measuring sensors can preferably be arranged above and a number of measuring sensors below that of the conveying device. Alternatively or additionally, however, all measuring sensors can also be arranged above or all measuring sensors below the conveying device.

If the measuring sensors are arranged below the conveying device, it can have corresponding recesses or openings in order to enable a corresponding measurement by means of the measuring sensors. An arrangement of at least one measuring sensor or several measuring sensors below the conveyor has the advantage that the distance between a workpiece surface and the measuring sensor is independent of the thickness of the workpiece and thus always remains constant. An arrangement of measuring sensors above the conveying device has the advantage that they are less affected by external influences, for example dust deposits.

The measuring device preferably has an evaluation unit which is designed to record the edge points determined by means of the measuring sensors and to process them in such a way that they can be mapped in a common coordinate system, in particular depending on the relative positions of the measuring sensors to one another. This makes it possible to combine at least two edge points that were detected by different measuring sensors, for example within a common coordinate system, and to use them to determine a workpiece geometry or workpiece dimensions. To determine the workpiece geometry, the edge points determined for each workpiece edge can be connected to form straight lines, the corresponding workpiece geometry resulting from this in the common coordinate system.

It is an advantage of the invention that at least two measuring sensors can be triggered in an event-controlled manner in order to simultaneously carry out a measurement of at least two edge points of a workpiece edge as a function of the corresponding trigger signal. In an advantageous development, at least two measurement sensors are arranged and designed in such a way that they measure a front edge point of the front edge and/or a rear edge point of the rear edge depending on the trigger signal in the run-in area. Additionally or alternatively, at least two measurement sensors are arranged and designed in such a way to measure a front edge point of the front edge and/or a rear edge point of the rear edge depending on the trigger signal in the run-out area.

According to the development described above, it is possible in a simple manner to determine the leading edge points and/or the trailing edge points of the workpiece using a pair of sensors, particularly if the course of the corresponding workpiece edges is relevant to the quality assessment of the workpiece. In particular, the edge points of the trailing edge in the run-in area and the edge points of the leading edge in the run-out area can be determined simultaneously and as a function of the trigger signal when the workpiece edges are completely within the measuring range.

In an advantageous development, at least one measuring sensor, which is designed to detect a leading edge point or a trailing edge point within the entry area or the exit area, is configured as a laser light section sensor or line sensor.

The measuring sensor preferably has a detection area which essentially extends along a measuring axis and is preferably aligned with its measuring axis parallel to the conveying axis of the workpiece. It is within the scope of the advantageous development that the trigger signal can be output with a time delay.

It is an advantage of the development described above that the location-resolved determination of an edge point is possible by means of a measuring sensor, which has a simple design with only one measuring axis. In particular, the use of matrix-type sensors can be dispensed with. In an advantageous development, the measuring area comprises at least one side area and at least one measuring sensor is arranged and designed to measure a side edge point of a side edge in a spatially resolved manner in the side area.

In addition to the front and rear edges of the workpiece, the course of the side edges can also be relevant to quality. For this reason, it is an advantage of the development described above that the measuring area of the measuring device has the side area in addition to the inlet and outlet areas in order to determine a side edge point and preferably depending on this to be able to determine a side edge course of the workpiece within the measuring area .

In an advantageous development, at least one measuring sensor of the measuring device is mounted so that it can be adjusted orthogonally and/or parallel to the conveying axis of the workpiece in order to set a dimension of the measuring area. Alternatively or preferably in addition, at least one measuring sensor can be arranged at an angle to the conveying axis, with the angle preferably being adjustable.

It is within the scope of the advantageous development described above that the measuring sensor can be adjusted by means of a controllable actuator. In particular, it can be an electrically controllable actuator. The actuator is preferably controlled by means of a control unit as a function of the dimensions of an incoming workpiece.

In an advantageous development, the measurement sensors are arranged in such a way that the measurement area is designed in the shape of a frame.

The advantage of a measuring area designed in the form of a frame is that the measuring sensors can be designed and arranged in such a way that their respective detection areas do not have to cover the entire workpiece. Instead, the measuring area can be designed in such a way that it essentially corresponds to the course of the workpiece edges of the workpiece. The workpiece edges and preferably the workpiece corners of the workpiece to be measured can be completely enclosed by the measuring area. The measurement area preferably has a frame width which depends on a dimension of at least one of the measuring sensors and/or its detection range. As a result, the dimensions of the measuring area can be set as a function of the measuring sensor used and in this case can preferably be adapted to the dimensions of the workpiece to be expected.

In an advantageous development, at least one measuring sensor extends essentially along a measuring axis and is arranged in such a way that the measuring axis of the measuring sensor and the conveying axis of the workpiece enclose an acute angle, with the measuring sensor extending partially into the inlet area or into the outlet area and partly extends into the side area in order to measure a front edge point or a rear edge point of the workpiece and additionally a side edge point of the workpiece depending on the trigger signal.

According to the advantageous development described above, only one measuring sensor, which is preferably designed as a line sensor, is required to measure two edge points of two different workpiece edges at the same time. The device preferably has a total of four measuring sensors arranged in this way in order to be able to measure eight edge points as a function of the trigger signal.

In an advantageous development, at least one measuring sensor is designed as a distance sensor and has at least one measuring axis, which is in particular aligned orthogonally to the conveying axis, the distance sensor being arranged in such a way as to detect a side edge point of a side edge in the side area. The measuring sensor designed as a distance sensor can easily be designed as a laser distance sensor and is preferably arranged in such a way that its detection area extends laterally into the conveying area of the workpiece to be measured. During the conveying movement of the workpiece, it enters the detection range of the distance sensor, so that the distance sensor can determine a side edge point on a side surface of the workpiece.

In an advantageous development, at least one measuring sensor, preferably all measuring sensors, is arranged on a thermally invariant carrier element. The arrangement of the measuring sensor on the thermally invariant carrier element makes it possible to reduce temperature-related influences on the measuring accuracy of the measuring device.

In an advantageous development, the measuring device for determining a relative position, in particular a distance, between two measuring sensors, preferably all measuring sensors, includes at least one distance sensor. Thus, the relative position of two measuring sensors, preferably all measuring sensors, in particular their distance from one another, can be determined by means of at least one distance sensor. In this way, the position of the measuring sensors in relation to one another can be determined at any time.

The method according to the invention or an advantageous development thereof is preferably suitable for being carried out with the measuring device according to the invention or an advantageous development thereof. The measuring device according to the invention or an advantageous development thereof is preferably suitable for carrying out the method according to the invention or an advantageous development thereof.

Further preferred features and embodiments of the method according to the invention and the device according to the invention are explained below using exemplary embodiments. The exemplary embodiments only relate to advantageous configurations of the invention and therefore do not restrict them.

Show it

FIG. 1 shows a plate-shaped workpiece to be measured with four

workpiece edges;

Figure 2 shows a first embodiment of a measuring device for

Measurement of a plate-shaped workpiece;

Figure 3 shows a second embodiment of a measuring device for

Measurement of a plate-shaped workpiece; FIGS. 4a), 4b) a third exemplary embodiment of a measuring device for measuring a plate-shaped workpiece at different points in time;

FIGS. 5a), 5b) a fourth exemplary embodiment of a measuring device for measuring a plate-shaped workpiece at different points in time;

FIGS. 6a), 6b) a fifth exemplary embodiment of a measuring device for measuring a plate-shaped workpiece at different points in time;

FIGS. 7a), 7b) a sixth exemplary embodiment of a measuring device for measuring a plate-shaped workpiece at different points in time;

FIG. 1 shows a conveyor belt as a conveyor device 1, by means of which a panel-shaped workpiece 2 is conveyed along a conveying axis 7. Alternatively, a roller conveyor or roller bar conveyor can also be used as the conveyor device 1 . The workpiece 2 comprises a front edge 3, a rear edge 4 and two side edges 5 and 6.

FIG. 2 shows the workpiece 2 according to FIG. 1, which has reached the measuring area 8 of a measuring device 9 as a result of its conveying movement. The measuring device 9 comprises eight non-contact measuring sensors 10′, 10″, 11′, 11″, 12′, 12″, 13′, 13″, each of which is designed as a photosensitive line sensor whose respective detection area extends essentially along a sensor’s own measuring axis. According to FIG. 2, the conveyor belt 1 has several segments 1'. 1", 1'", 1"", 1""', which are spaced apart from one another along the conveying axis 7. As a result of its conveying movement along the conveying axis 7, the workpiece 2 temporarily rests on the segments 1", 1" and 1"", with its edges 3, 4, 5, 6 over the segments 1", 1" and 1"". protrude. In an alternative embodiment, the segments 1 '. 1", 1'", 1"", 1""' each extend along the conveying axis 7, so that the areas in between also essentially extend along the conveying axis 7. In other words can the gaps between the segments '. 1", T", 1", 1""' extend both along the conveying axis and transversely to it. The segments T. 1", 1'", 1"", 1""' can, for example, also be rollers of a roller conveyor.

The measuring sensors 10' and 10'' are aligned with their measuring axes parallel to the conveying axis 7 of the conveyor belt 1 located above them and are arranged in an inlet area 14 of the measuring area 8. The measuring sensors 11' and 11'' are also aligned with their measuring axes parallel to the conveying axis 7 of the conveyor belt 1 located above them and are arranged in an outlet area 15 of the measuring area 8.

The measuring sensors 12' and 12'' are aligned with their respective measuring axes orthogonally to the conveying axis 7 of the conveyor belt 1 located above them and are arranged in a first side area 16 of the measuring area 8. The measuring sensors 13' and 13'' are also aligned with their respective measuring axes orthogonally to the conveying axis 7 of the conveyor belt 1 located above them and are arranged in a second side area 17 of the measuring area 8. Alternatively, some of the measuring sensors 10', 10", 1T, 11", 12', 12", 13', 13" can be arranged above and below the conveyor belt 1 or a conveyor device 1. All measuring sensors 10', 10", 11', 11", 12', 12", 13', 13" can also be arranged above the conveyor belt 1 or a conveyor device 1.

The measuring device 8 with its measuring sensors 10′, 10″, 1T, 11″, 12′, 12″, 13′, 13″ is used to measure the geometry and dimensions of the workpiece 2 during its movement through the measuring area 8 to determine a large number of edge points. As can be seen from FIG. 2, two edge points are measured for the front edge 3, the rear edge 4 and the two side edges 5, 6 of the workpiece 2. Due to the rectilinear course of the workpiece edges, it is possible to reconstruct the outer contours of the workpiece 2 using the measured edge points and to draw conclusions about its geometry and its dimensions.

In the exemplary embodiment shown in FIG. 2, it is advantageous that the detection of the edge points by means of the measurement sensors 10', 10", 1T, 11", 12', 12", 13', 13” takes place at the same time. In order to make this possible, a trigger sensor 18 or 19 in the form of a light barrier is arranged in the inlet area 14 and in the outlet area 15 . These are used to identify whether the front edge 3 of the workpiece 2 is within the outlet area 15 and/or whether the rear edge 4 is inside the inlet area 14 . If the trigger sensors 18 and 19 detect whether the front edge 3 and rear edge 4 of the workpiece 2 are in at least one of the positions described above, the trigger sensors 18, 19 alone or together emit a trigger signal to the measuring device 9, which then Measuring sensors 10', 10", 1 T, 11", 12', 12", 13', 13" are triggered simultaneously.

FIG. 3 shows the workpiece 2 according to FIG. In contrast to the measuring device according to FIG. 1, the device does not have eight but only four measuring sensors 10', 11', 12' and 13'. These are each designed as photosensitive line sensors whose detection areas each extend essentially along a sensor's own measuring axis.

The measuring sensors 10', 1T, 12' and 13' are arranged with their respective measuring axes opposite the conveying axis 7 of the workpiece 2 in such a way that between the conveying axis and the measuring axes of the measuring sensors 10', 11', 12' and 13' acute angle is included. This makes it possible to use one of the measuring sensors to measure two edge points of two different workpiece edges in a spatially resolved manner in a single measurement recording.

In the exemplary embodiment shown in FIG. 3, the conveyor device 1 has the segments T, 1″ and T″, which are spaced apart from one another along the conveyor axis 7 . In the exemplary embodiment shown here, the workpiece 2 rests on the segment 1″ so that its workpiece edges 3, 4, 5 and 6 protrude between the segments 1′ and 1″ and between the segments 1″ and T″. The measurement sensors 10', 1T, 12' and 13' are arranged below the segments T, 1" and T" and each detect two edge points. The measuring sensor 10 ′ is arranged in such a way that its detection area protrudes both into the inlet area 14 and into the first side area 16 . The measuring sensor 11 ′ is arranged in such a way that its detection area protrudes both into the inlet area 14 and into the second side area 17 . The measuring sensor 12 ′ is arranged in such a way that its detection area protrudes both into the outlet area 15 and into the first side area 16 . The measuring sensor 13 ′ is arranged in such a way that its detection area protrudes both into the outlet area 15 and into the second side area 17 . In the exemplary embodiment shown, the measurement sensors can be triggered by the leading edge 2 being detected by at least one of the measurement sensors 12' or 13' in the run-out area 15 and/or by the rear edge 4 being detected by at least one of the measurement sensors 10' or 1 T in the Lead-in area 14 is recognized. The edge measurement by means of the measurement sensors 10', 11', 12' and 13' takes place simultaneously and as a function of a trigger signal which is output by the measurement sensor which detects the front edge 3 or rear edge 4.

FIG. 4 shows the workpiece 2 according to FIG. The workpiece 2 reaches two different measuring positions, which are shown in views a) and b).

In contrast to the measuring devices according to FIGS. 2 and 3, the measuring device 9 according to FIG. 4 includes seven measuring sensors 10', 10", 11', 11", 12', 12" and 13'. These are each designed as photosensitive line sensors and have a detection area which extends essentially along a sensor's own measuring axis.

The measuring sensors 10 ′ and 10 ″ are aligned with their measuring axes parallel to the conveying axis of the conveyor belt 1 located below them and are arranged in an inlet area 14 of the measuring area 8 . For the sake of clarity, the conveyor belt 1 is shown in one piece, but can be divided into several segments T, 1", 1 . . . in accordance with the descriptions of FIGS. The measuring sensors 1T and 11″ are also aligned with their measuring axes parallel to the conveying axis of the conveyor belt 1 below them and are arranged in an outlet area 15 of the measuring area 8 .

The measuring sensors 12' and 12'' are aligned with their measuring axes orthogonal to the conveying axis of the conveyor belt 1 located below and are arranged in a first side area 16 of the measuring area 8. The measuring sensor 13 ′ is also aligned with its measuring axis orthogonally to the conveying axis of the conveyor belt 1 located below and is arranged in a second side area 17 of the measuring area 8 .

In the first measuring position of the workpiece 2 according to view a) of FIG. 4, its trailing edge 4 is in the entry area 14 of the measuring area 8. The presence of the trailing edge 4 is detected by means of the trigger sensor 18 and a first trigger signal is sent to the measuring sensors 10' , 10" as well as 12' and 13'. Depending on the trigger signal, the measuring sensors 10' and 10" each detect an edge point of the rear edge 4, while the measuring sensors 12', 12" and 13' each detect an edge point of the side edges 5, 6 of the workpiece 2.

The workpiece 2 then moves into the second measuring position according to view b) of Figure 4. In this second measuring position, the workpiece 2 is located with its front edge 3 in the run-out area 15 of the measuring area 8. The presence of the front edge 3 is detected by means of the trigger sensor 19 and a second trigger signal is output to the measuring sensors 11′, 11″ and 12′, 12″ and 13′. Depending on the second trigger signal, the measuring sensors 11' and 11" each detect an edge point of the rear edge 4, while the measuring sensors 12', 12" and 13', in addition to the already detected edge point of the side edges 5, 6, each have a further edge point of the side edges 5, 6 record.

Using the edge points that are measured for the front edge 3 and for the rear edge 4, a front edge profile and a rear edge profile can be determined for the workpiece within the measuring range. A side edge course for the side edge 5 can already be determined by the first measurement using the measuring sensors 12' and 12''. The second measurement using the Measuring sensors 12′ and 12″ make it possible to verify a side edge profile of the side edge 5 or, for example, to form an average value for the side edge profile and to increase the reliability of the measurement. A side edge profile can be determined using the side edge 6 in that the trigger sensors 18 and 19 each output a time stamp at their respective trigger times, which can be used together with the conveying speed of the workpiece to determine the side edge profile.

FIG. 5 shows the workpiece 2 according to FIG. The workpiece 2 reaches two different measuring positions, which are shown in views a) and b).

In contrast to the measuring devices according to FIGS. 2, 3 or 4, the measuring device 9 according to FIG. 5 comprises six measuring sensors 10', 10", 11', 11", 12' and 13'. These are each designed as photosensitive line sensors and have a detection area which extends essentially along a sensor's own measurement axis.

The measuring sensors 10' and 10'' are aligned with their measuring axes parallel to the conveying axis 7 of the conveyor belt 1 located below them and are arranged in an inlet area 14 of the measuring area 8. For the sake of clarity, the conveyor belt 1 is shown in one piece, but can be divided into several segments T, 1", T", . . . in accordance with the descriptions of FIGS. The measuring sensors 11' and 11'' are also aligned with their measuring axes parallel to the conveying axis 7 of the conveyor belt 1 located below them and are arranged in an outlet area 15 of the measuring area 8.

The measuring sensor 12 ′ is aligned with its measuring axis orthogonally to the conveying axis 7 of the conveyor belt 1 located below and is arranged in a first side area 16 of the measuring area 8 . The measuring sensor 13 ′ is also aligned with its measuring axis orthogonally to the conveying axis 7 of the conveyor belt 1 located below and is arranged in a second side area 17 of the measuring area 8 . In the first measuring position of the workpiece 2 according to view a) of Figure 5, this is located with its rear edge 4 in the entry area 14 and with its front edge 3 in the exit area 15 of the measuring area 8. The presence of the rear edge 4 is detected by the trigger sensor 18 and a first trigger signal is output to the measurement sensors 10', 10", 1T, 11" and 12' and 13'. Depending on the first trigger signal, the triggered measurement sensors 10', 10" each detect an edge point of the rear edge 4, while the triggered measurement sensors 11 11" each detect an edge point of the front edge 3 and the measurement sensors 12' and 13' each detect an edge point of the side edge 5, 6 capture.

The workpiece 2 then moves into the second measuring position according to view b) of Figure 5. In this second measuring position, its rear edge 4 is still in the entry area 14 and its front edge 3 is still in the exit area 15 of the measuring area 8. The presence of the The leading edge 3 is detected by the trigger sensor 19 and a second trigger signal is output to the measurement sensors 10', 10", 11', 11" and 12' and 13'. Depending on the first trigger signal, the triggered measuring sensors 10', 10" each detect an edge point of the trailing edge 4, while the triggered measuring sensors 11', 11" each detect an edge point of the leading edge 3 and the measuring sensors 12' and 13' each detect a further edge point of the previous one side edges 5, 6 that have already been measured.

As a result of the conveying movement of the workpiece 2, the edge points determined in the first and the second measuring position on the front edge 3 are offset in relation to one another. Likewise, the edge points determined in the first and in the second measurement position on the rear edge 4 are offset from one another. The respective offset is used to determine a distance between the edge points measured by the measurement sensors 12' and 13'. It is thus possible in a simple manner to draw conclusions about the corresponding course of the side edges on the basis of the two determined edge points of the side edges 5, 6. FIG. 6 shows the workpiece 2 according to FIG. The workpiece 2 reaches two different measuring positions, which are shown in views a) and b).

The measuring device according to FIG. 6 comprises six measuring sensors 10', 10", 1T, 12', 13' and 13". These are each designed as photosensitive line sensors and have a detection area which extends essentially along a measuring axis.

The measuring sensors 10' and 10'' are aligned with their measuring axes parallel to the conveying axis 7 of the conveyor belt 1 located below them and are arranged in an inlet area 14 of the measuring area 8. For the sake of clarity, the conveyor belt 1 is shown in one piece, but can be divided into several segments T, 1", T", . . . in accordance with the descriptions of FIGS. The measuring sensor 1 T is also aligned with its measuring axis parallel to the conveying axis 7 of the conveyor belt 1 located below it and is arranged in an outlet area 15 of the measuring area 8 .

The measuring sensor 12' is aligned with its measuring axis orthogonally to the conveying axis 7 of the conveyor belt 1 located below and is arranged in a first side area 16 of the measuring area 8. The measuring sensors 13' and 13'' are also aligned with their respective measuring axes orthogonally to the conveying axis 7 of the conveyor belt 1 located below and are arranged in a second side area 17 of the measuring area 8.

In the first measuring position of the workpiece 2, which is shown in view a) of Figure 6, the workpiece 2 is located with its front edge 3 in the entry area 14. This is detected by a trigger sensor 18 also arranged in the entry area 14, whereupon this outputs the first trigger signal to the measurement sensors 10', 10" and 13'. In this first measuring position, the measuring sensors 10' and 10'' each determine an edge point of the front edge 3. The measuring sensor 13' determines an edge point of the side edge 5, 6 inside of the side area 17. As a result of its conveying movement, the workpiece 2 then reaches the second measuring position, which is shown in view b) of FIG.

In the second measuring position according to view b) of FIG. 6, the workpiece 2 is located with its rear edge 4 in the entry area 14. This is detected by the trigger sensor 18, which is also arranged in the entry area 14, whereupon this sends a second trigger signal to the measuring sensors 10', 10", 13" and 11 '. The measuring sensors 10' and 10" each determine an edge point of the rear edge 4 in this second measuring position. The measuring sensor 13" determines an edge point on the side edge 5, 6 for which an edge point was already determined in the first measuring position by means of the measuring sensor 13'. The measuring sensor 11' determines an edge point on the front edge 3, which protrudes into the outlet area 15.

It is possible to determine the workpiece geometry from the totality of the edge points measured in the first and second measuring position. In particular, this takes place depending on how the measuring sensors 10', 10", 11', 12', 13' and 13" are arranged in relation to one another. In particular, this occurs depending on the distance 20 between the measuring sensor 11' and the measuring sensor 13' and depending on the distance 21 between the two measuring sensors 13' and 13".

FIG. 7 shows the workpiece 2 according to FIG. In the process, the workpiece 2 reaches two different measurement positions, which are shown in views a) and b).

The measuring device according to FIG. 7 comprises seven measuring sensors 10', 10", 1T, 12', 12", 13' and 13". These are each designed as photosensitive line sensors and have a detection area which extends essentially along a measuring axis.

The measuring sensors 10 ′ and 10 ″ are aligned with their respective measuring axes parallel to the conveying axis 7 of the conveyor belt 1 located below them and are arranged in an inlet area 14 of the measuring area 8 . The Measuring sensor 11 ′ is also aligned with its measuring axis parallel to the conveying axis 7 of the conveyor belt 1 located below it and is arranged in an outlet area 15 of the measuring area 8 . For better clarity, the conveyor belt 1 is shown in one piece, but can be divided into several segments 1', 1", 1'", . . . in accordance with the descriptions of FIGS.

The measuring sensors 12' and 12'' are aligned with their measuring axes orthogonal to the conveying axis 7 of the conveyor belt 1 located below and are arranged in a first side area 16 of the measuring area 8. The measuring sensors 13' and 13'' are also aligned with their respective measuring axes orthogonally to the conveying axis 7 of the conveyor belt 1 located below and are arranged in a second side area 17 of the measuring area 8.

In the first measuring position of the workpiece 2, which is shown in view a) of Figure 7, the workpiece 2 is located with its front edge 3 in the entry area 14. This is detected by a trigger sensor 18 also arranged in the entry area 14, whereupon this a outputs the first trigger signal to the measuring sensors 10', 10'' and 12' and 13'. In this first measuring position, the measuring sensors 10' and 10" each determine an edge point of the front edge 3. The measuring sensors 12' and 13' each determine an edge point of the side edges 5, 6 within the side regions 16 and 17. The workpiece 2 then arrives as a result of its Conveying movement into the second measuring position, which is shown in view b) of FIG.

In the second measuring position according to view b) of FIG. 7, the workpiece 2 is located with its rear edge 4 in the entry area 14. This is detected by the trigger sensor 18, which is also arranged in the entry area 14, whereupon this sends a second trigger signal to the measuring sensors 10', 10", 12", 13" and 11 ' outputs. The measuring sensors 10' and 10" each determine an edge point of the rear edge 4 in this second measuring position. The measuring sensors 12" and 13" each determine an edge point on the side edges 5, 6 to those in the first measuring position already by means of the measuring sensors 12' and 13 ' one edge point has already been determined. The measuring sensor 10 ′ determines an edge point on the front edge 3 which protrudes into the run-out area 15 . It is possible to determine the workpiece geometry from the totality of the edge points measured in the first and second measuring position. In particular, this occurs depending on how the measuring sensors 10', 10", 11', 12', 12", 13' and 13" are arranged relative to one another. In particular, this occurs depending on the distance 20 between the measuring sensor 11 and the measuring sensor 13' and depending on the distance 21 between the two measuring sensors 13' and 13''.

reference number

1 conveyor

T, 1", 1 ... segment

2 workpiece

3 leading edge

4 trailing edge

5 side edge

6 side edge

7 conveyor axis

8 measuring range

9 measuring device

10', 10" measuring sensor

11 11" measuring sensor

12', 12" measuring sensor

13', 13" measuring sensor

14 inlet area

15 run-out area

16 page range

17 page range

18 trigger sensor

19 trigger sensor

20 distance

21 distance

Claims

Claims Method for measuring a plate-shaped workpiece (2) with the following method steps:

A) Conveying the workpiece (2) along a conveying axis (7) through a measuring area (8) of a measuring device (9) with a plurality of non-contact measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13"), which are each designed as line sensors and designed to detect at least one edge point of the workpiece (2) in a spatially resolved manner within the measuring area (8);

B) Detecting a measurement position of the workpiece (2) by a rear edge (4) and/or a front edge (3) of the workpiece (2) in an entry area (14) and/or in an exit area (15) of the measurement area (8). is recognized;

C) Outputting at least one trigger signal to the measuring device (9) as soon as the measuring position of the workpiece (2) is detected;

D) Edge measurement of the workpiece (2) using the measuring sensors (10', 10", 1T, 11", 12', 12", 13', 13") of the measuring device (9), with at least two of the measuring sensors (10' , 10", 1 T, 11", 12', 12", 13', 13") can be triggered simultaneously, depending on the trigger signal, by at least two edge points of the workpiece

(2) to determine preferably two edge points per workpiece edge within the measuring area (8) in a spatially resolved manner;

E) determining at least one parameter of a workpiece geometry and/or a workpiece position within the measuring area (8) as a function of the detected edge points. Method according to Claim 1, in which the workpiece is conveyed at least in method step A) by means of a conveying device (1) along the conveying axis, the workpiece at least in the measuring area having at least one workpiece edge to be measured over the conveying device (1) or between two parts of the Conveyor (1) protrudes and the measuring sensors (10', 10", 1T, 11", 12', 12", 13', 13") are arranged below the conveyor (1).

36

3. The method according to claim 1 or 2, in which by means of at least one of the measuring sensors (10', 10", 1T, 11", 12', 12", 13', 13") and/or an additional trigger sensor (18, 19), in particular a light barrier, the measurement position is detected in method step B) and the trigger signal is output in method step C).

4. Method according to one of the preceding claims, in which in method step D) in the inlet area (14) by means of at least two measuring sensors (10', 10", 1T, 11", 12', 12", 13', 13") , two rear edge points of the rear edge (4) are measured spatially resolved and preferably in method step E) a rear edge profile of the workpiece (2) within the measuring area (8) is determined with the two rear edge points.

5. Method according to one of the preceding claims, in which in method step D) in the outlet area (15) by means of at least two measuring sensors (10', 10", 1T, 11", 12', 12", 13', 13") , two front edge points of the front edge (3) are measured spatially resolved and preferably in method step E) with the two front edge points a front edge profile of the workpiece (2) within the measuring area (8) is determined.

6. The method according to claim 4 or 5, in which the measuring area (8) comprises at least one side area (16, 17) through which the workpiece (2) is conveyed with a side edge (5, 6) in method step A) and in method step D) at least one side edge point is preferably detected in the side area (16, 17) as a function of the trigger signal by means of at least one measuring sensor (10', 10", 1T, 11", 12', 12", 13', 13") in which the measuring area (8) has two side areas (16, 17) and the workpiece (2) has two side edges (5, 6), the workpiece (2) having a first side edge (5, 6) in method step A) by a first of the two side areas (16, 17) and with a second side edge (5, 6) through a second of the two side areas (16, 17) and in method step D) in the first side area (16, 17) by means of at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") at least

37 a side edge point of the first side edge (5, 6) and in the second side area (16, 17) by means of at least one other measuring sensor (10', 10", 11', 11", 12', 12", 13', 13") at least one side edge point of the second side edge (5, 6) is detected.

7. The method according to claim 6, in which in method step D) in the side area (16, 17) depending on the trigger signal by means of two measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13"), two side edge points of a side edge (5, 6) are detected simultaneously and in method step E) a side edge profile of the side edge (5, 6) is determined within the measuring area (8) with the two side edge points, preferably in the case of method step D) in the first of two side areas (16, 17) by means of at least two measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13") at least two side edge points of the first side edge (5, 6) and in the second side area (16, 17) at least two side edge points of the second side edge (5, 6) are detected by means of at least two other measuring sensors and in method step E) with the two side edge points of the first side edge (5, 6) a side edge course of the first side edge (5, 6) is determined within the measuring area (8) and with the two side edge points of the second side edge (5, 6) a side edge profile of the second side edge (5, 6) is determined within the measuring area (8).

8. The method according to claim 6, in which in method step B) at least two measuring positions of the workpiece (2) are detected during the conveying movement of the workpiece (2), with the rear edge (4) being detected in a method step B1) in the inlet area (14). and in a method step C1) a first trigger signal is output to the measuring device (9), and in a method step B2) the leading edge (3) is detected in the run-out area (15) and in a method step C2) a second trigger signal to the measuring device (9) is output, in a method step D1) depending on the first trigger signal by means of at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") in the side area ( 16, 17), preferably in both side areas (16, 17), a side edge point of a side edge (5, 6) is detected, and in a method step D2) depending on the second trigger signal in the side area (16, 17) by means of the measuring sensor (10', 10", 1 T, 11 ", 12', 12", 13', 13") due to the conveying movement of the workpiece (2) another side edge point of the side edge (5, 6) is detected and output. Method according to Claim 1, in which in method step B) during the conveying movement of the workpiece (2) at least two measuring positions of the workpiece (2) are detected, with the front edge (3) being detected in a method step B1) in the inlet area (14) and in a method step C1) a first trigger signal is output to the measuring device (9), and in a method step B2) the trailing edge (4) is detected in the lead-in area (14) and in a method step C2) a second trigger signal to the measuring device

(9) is output, whereby in a method step D1) depending on the first trigger signal in the entry area (14) by means of at least two measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13 ") two front edge points of the front edge (3) are detected and in a method step D2) depending on the second trigger signal in the run-in area (14) by means of at least two measuring sensors (10', 10", 1 T, 11", 12', 12" , 13', 13") two rear edge points of the rear edge (4) are detected and simultaneously in the outlet area (15) by means of at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") a front edge point of the front edge (3) is detected, and preferably in method step E) with the two front edge points from method step D1) and with the front edge point from method step D2) and the two rear edge points from method step D2) a front edge profile and a rear edge profile of the workpiece (2) is determined within the measuring range (8). Method according to Claim 9, in which the measuring area (8) comprises at least one side area (16, 17) through which the workpiece (2) is conveyed with a side edge (5, 6) in method step A), wherein in method step D1) depending on the first trigger signal in the side area (16, 17) by means of at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") a side edge point of a side edge (5, 6) is detected and in method step D2) depending on the second trigger signal in the side area (16, 17) by means of at least one measuring sensor (10',

10", 1 T, 11", 12', 12", 13', 13") as a result of the conveying movement of the workpiece (2) another side edge point of the side edge is detected and preferably in method step E) with the two side edge points from method step D1) and method step D2) a side edge course of the workpiece edge is determined.

11. The method according to claims 4 to 10, in which in method step E) a workpiece length and/or a workpiece width and/or a relative orientation is determined as a function of the rear edge profile and/or the front edge profile and/or at least one side edge profile within the measuring region (8). at least two workpiece edges and/or a position of the workpiece (2) within the measuring area (8) is determined.

12. The method according to at least one of claims 4 to 11, in which the at least one measuring sensor (10', 10", 1T, 11", 12', 12", 13', 13") and/or the additional trigger sensor ( 18, 19) in the entry area (14) and/or the at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") and/or the additional trigger sensor (18 , 19) is adjusted in the outlet area (15) before method step A) along the conveying axis (7) in order to adapt a longitudinal dimension of the measuring area (8) to an expected workpiece length.

13. The method according to at least one of claims 4 to 12, in which at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") of one of the side areas (16, 17) is adjusted in particular orthogonally to the conveying axis (7) and depending on an expected workpiece width in order to adapt a transverse dimension of the measuring area (8) to an expected workpiece width.

14. The method according to any one of claims 1 to 13, in which, before carrying out method steps A) to E), in a method step 0) a zero adjustment of the measurement sensors is carried out using a measurement standard, in that method steps A) to E) are carried out with the measurement standard instead of a workpiece (2) and the measurement sensors ( 10′, 10″, 1 T, 11″, 12′, 12″, 13′, 13″) depending on a comparison between at least one determined normal geometry and the actual normal geometry. Method according to one of Claims 1 to 14, in which before carrying out method steps A) to E) in a method step 0) by means of at least one reference element, which preferably extends parallel to a thermal deformation axis of the measuring device, or a distance sensor, a distance between at least two measuring sensors of the measuring device is determined and the parameter of the workpiece geometry and/or the workpiece position within the measuring range is determined in method step E) as a function of the distance determined in method step 0). Measuring device (9) for measuring a plate-shaped workpiece (2), preferably for carrying out the method according to one of the claims

1 to 15, with a plurality of non-contact measurement sensors (10', 10", 11', 11", 12', 12", 13', 13"), each of which has a detection area and the detection areas at least partially include a measurement area (8th ) form and/or are included in this, and wherein the measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13") are each designed as line sensors and are designed for this purpose on a to carry out a spatially resolved edge measurement of the plate-shaped workpiece (2) conveyed through the measuring area (8) and along a conveying axis (7) and thereby to determine at least one edge point, in particular one edge point for each workpiece edge, characterized in that the measuring area (8) along the conveying axis (7) comprises an inlet area (14) and an outlet area (15) and at least one of the measuring sensors (10', 10", 1T, 11", 12', 12", 13', 13") and/or an additional one trigger sensor (18, 19) is arranged and designed in such a way that a rear edge (4) and/or a front edge (3) is triggered during a conveying movement of the workpiece (2) within the inlet area (14) and/or the outlet area (15).

41 of the workpiece (2), the measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") or the trigger sensor (18, 19) being connected to the measuring device (9 ) is connected in terms of signals in order to output at least one trigger signal to the measuring device (9) for spatially resolved edge measurement of the workpiece (2) when the rear edge (4) and/or the front edge (3) is detected.

17. Measuring device (9) according to claim 16, in which at least two measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13") are arranged and designed in such a way that, depending on the trigger signal in the run-in area (14) to measure a leading edge point of a leading edge (3) and/or a trailing edge point of a trailing edge (4).

18. Measuring device (9) according to one of claims 16 or 17, in which at least two measuring sensors (10', 10", 1T, 11", 12', 12", 13', 13") are arranged and designed in such a way to measure a leading edge point of a leading edge (3) and/or a trailing edge point of a trailing edge (4) depending on the trigger signal in the run-out area (15).

19. Measuring device (9) according to one of claims 16 to 18, in which the measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13"), which is used to detect a leading edge point or a trailing edge point within the entry area (14) or the exit area (15), is designed as a laser light section sensor or line sensor, and has at least one measuring axis which is aligned parallel to the conveying axis (7) of the workpiece (2).

20. Measuring device (9) according to one of claims 16 to 19, in which the measuring area (8) comprises at least one side area (16, 17) and at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") is arranged and designed to measure a side edge point of a side edge (5, 6) in the side area (16, 17) as a function of the trigger signal.

42 Measuring device (9) according to Claim 20, in which the measuring area (8) comprises two side areas (16, 17), in each of which at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13 ', 13"), preferably two measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13"), are arranged around at least one side edge point of two side edges (5, 6) to eat. Measuring device (9) according to one of Claims 16 to 21, in which at least one measuring sensor (10', 10", 11', 11", 12', 12", 13', 13") of the measuring device (9) is orthogonal and/or or is mounted adjustably parallel to the conveying axis (7) of the workpiece (2) in order to set a dimension of the measuring area (8). Measuring device (9) according to one of Claims 16 to 22, in which the measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13") are arranged in such a way that the measuring range (8th ) is frame-shaped. Measuring device (9) according to one of Claims 15 to 22, in which at least one measuring sensor (10', 10", 11', 11", 12', 12", 13', 13") extends essentially along a measuring axis and is arranged in such a way that the measuring axis of the measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") and the conveying axis (7) of the workpiece (2) enclose an acute angle, so that the measuring sensor (10', 10", 1T, 11", 12', 12", 13', 13") extends partially into the inlet area (14) or into the outlet area (15) and partially into the side area (16, 17) in order to measure a front edge point or a rear edge point of the workpiece (2) and additionally a side edge point of the workpiece (2) as a function of the trigger signal. Measuring device (9) according to one of Claims 16 to 24, in which at least one measuring sensor (10', 10", 1 T, 11", 12', 12", 13', 13") is designed as a distance sensor, and at least has a measuring axis which is aligned orthogonally to the conveying axis (7) and wherein the distance sensor is arranged in such a way as to detect a side edge point of a side edge (5, 6) in the side region (16, 17).

43 Measuring device (9) according to one of Claims 16 to 25, in which at least one measuring sensor (10', 10", 11', 11", 12', 12", 13', 13"), preferably all measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13"), is arranged on a thermally invariant carrier element. Measuring device (9) according to one of Claims 16 to 26, with a thermally invariant measuring element, in particular a reference scale, which is arranged parallel to a thermal deformation axis of the measuring device and is designed to indicate a thermally induced, relative displacement of at least two measuring sensors and/or that the measuring device (9) for determining a relative position of two measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13"), preferably all measuring sensors (10', 10", 1 T, 11", 12', 12", 13', 13"), in particular their distance (20, 21) to one another, comprises at least one distance sensor.

44