WO2002086419A1

WO2002086419A1 - Method and device for determining the radius, the sharpness or the shape of edges

Info

Publication number: WO2002086419A1
Application number: PCT/EP2002/004368
Authority: WO
Inventors: Gunther Röder
Original assignee: Roeder Gunther
Priority date: 2001-04-22
Filing date: 2002-04-20
Publication date: 2002-10-31
Also published as: EP1423657A1; DE10162279A1

Abstract

The invention relates to a method and device for determining the radius, the sharpness or the shape of edges (9), particularly of cutting edges or of the presence of notches or the like. To this end, a light beam is directed at the edge (9), and the radiant power reflected by the edge is measured. The radius, the sharpness, the shape or the presence or the size of notches or wear marks is determined from this measurement.

Description

Method and device for determining the radius, sharpness or shape of edges

Description

Due to the requirements regarding the quality and process reliability of production processes, it is necessary to assess the edge sharpness of cutting, punching, cutting or cutting tools of all kinds or the quality of edges on workpieces. The edge sharpness of cutting tools determines the minimum cutting thickness and the cutting forces, especially the passive force, as well as the surface quality of the workpiece. Cut-outs in the cutting edge are particularly important for the surface quality of workpieces during machining. This also applies to shear cutting and cutting tools. In the case of cutting punch knives, the cut quality, the complete punching and the punching force depend on the edge sharpness, i.e. above all on the edge radius and the cutting edge angle.

Edges with optical properties are often not allowed to have cutouts. With wipers and other rubber strips as well as with sealing rings, the wiping or sealing function also depends on the edge sharpness and its freedom from breakouts or irregularities.

Work is already known which deals with optical methods for measuring the sharpness of cutting edges (Tang, W.: Optical measurement of the edge sharpness of cutting tools, dissertation University of Kaiserslautern, 1990). Within the framework of research projects, measuring devices for determining the edge sharpness have emerged from the knowledge gained here and have been published. Optical measuring devices for determining the edge position are commercially available.

The present invention has for its object to provide a simple and reliable way to determine the properties of edges, in particular cutting edges.

The object is achieved by a method for determining the radius, the sharpness or the shape of edges, in particular cutting edges, or the presence of cutouts or the like, which is characterized in that an illuminating beam is directed onto the edge and the radiation power reflected by it measured and from this the radius, the sharpness, the shape of the edge or the presence or size of breakouts or wear marks is determined. If the edge is dull, ie has a large radius, the light striking the edge is strongly scattered, that is to say the radiation power reflected by the edge is high. So the lower the reflected radiation power, the sharper the edge must be. Outbreaks in the edge also cause changes in the scattering of the illumination beam. Such outbreaks can also be detected by measuring the radiation power reflected by the edge. In particular, deviations from the average radiation power are used. To determine the edge properties, the radiation power reflected back from the edge in the direction of irradiation and at a certain angle around this direction can preferably be measured. The reflected scattered light can be removed from the beam path illuminating the edge by means of a beam splitter couple out.

In order to achieve the smallest possible illumination beam diameter, which is particularly advantageous in the case of sharp edges, the illumination beam can be directed onto the edge by means of a focusing device. The reflected scattered light can then be picked up and reproduced again by the same focusing device through which the illuminating beam also passes. Of course, the reflected scattered light can also be picked up by a separate imaging device.

As a rule, the determination of the edge sharpness or edge shape at individual selected measuring points of the cutting edge, which are exposed to special stresses, is sufficient to be able to conclude the shape and sharpness of the entire edge. However, there are also applications in which the entire course of the edge must be examined for its sharpness and shape or for breakouts. In such a case, the illuminating beam can be moved relative to the edge in such a way that it sweeps the length.

The intensity of the illuminating beam is not constant over its entire diameter. For a high accuracy of the measurement, it is therefore advantageous to direct the beam onto the edge in such a way that the intensity maximum lies on the cutting edge and the scattered light reflected back from the intensity maximum of the illuminating beam is evaluated. The intensity maximum is usually in the center of the beam.

The device for carrying out a method according to the invention for determining the radius, sharpness or shape of edges is characterized by a light source, a detector for recording the proportion of light reflected by the edge and measuring its radiation power, and by a Evaluation. In addition, it can have a focusing device for focusing the illuminating beam onto the edge and / or for receiving the scattered light, and a beam splitter.

The detector can also be designed in various ways. For example, it can have one or more photodiodes.

In another configuration, it can have a four-quadrant photodiode, a secondary electron multiplier, an avalanche photodiode, a pin diode or a row of diodes. It is also possible to equip the detector with a CCD chip or another pixel matrix photo detector.

In order to adapt to different geometric opportunities, the detector can preferably be arranged in an adjustable manner in the device. A laser or another, approximately punctiform light source can be used as the light source. In order to enable the edge to be tracked, the light source and / or the edge can be arranged to be movable and / or rotatable and / or pivotable. The device can then be used, for example, to monitor the edge sharpness of circular knives or linear cutting edges. Monitoring can take place while circular knives or rotating forming tools are in operation. The monitoring of saw bands, circular saws, planing and milling tools is also possible with a device according to the invention.

Further advantages result if the diameter of the illuminating beam or of the focus spot in the beam path can be varied after the focusing device. This allows the measurement conditions to be optimally adapted to the shape of the edge. Depending on the measurement signals of the detector, the evaluation device can also control the relative movement of the light source and edge and / or the distance between the light source and edge and / or the adjustment of the beam diameter. This enables fully automatic tracking of the device parameters, in particular when scanning an edge over its entire length.

In order to prevent a disturbance in the regulation of the intensity of the light source by the light reflected back from the edge, a further detector for regulating the radiation power of the light source can be provided at a suitable point. It is then mainly illuminated by the light emanating from the light source and not at all or only slightly by the stray light from the edge.

In addition, an aperture can be arranged in front of the detector for the radiation power reflected by the edge, which shield fades out light that does not come from the cutting edge.

For the manufacture of the device, it is also advantageous if it has a modular structure and has at least one laser module, one objective module and one detector module. In addition, a beam splitter module and an intensity module for regulating the intensity of the laser diode can also be provided.

For example, a microscope objective or another corrected system for producing very small focal spots and good imaging of the cutting edge can preferably be arranged in the objective module. One or more aspherical lenses can also be used.

The detection module preferably contains a focusing device, an aperture and at least one photo detector. A correction cylinder lens or an arrangement of one or more prisms can be connected downstream of the laser diode in the laser module in order to correct the mostly slightly elliptical diameter of the laser diode beam again in a circular shape.

If a beam splitter module is provided, this can have, for example, a beam splitter cube, a beam splitter plate or a beam splitter film. In a construction of the device in which the reflected light is picked up again by the lens module, the beam splitter module represents the central module to which the other modules are preferably attached.

A preferred embodiment of a device according to the invention is described in more detail below with reference to the drawing.

Show it.

1 shows a schematic view of a device according to the invention for measuring the sharpness of a cutting edge;

2 shows a schematic representation of a four-quadrant photodiode for detecting a vertical edge;

3 shows a representation corresponding to FIG. 2 of a four-quadrant photodiode for the detection of a horizontal edge;

4 shows a representation corresponding to FIG. 2 of a four-quadrant photodiode for the detection of an edge running obliquely to the detector. With the optical arrangement according to FIG. 1 for measuring the edge shape, in particular the edge radius, which can be associated with the edge sharpness, bevels, breakouts and wear marks can also be identified. This creates a measurement result that does not explicitly describe the geometric relationships, but that maps the geometric relationships into a one-dimensional measurement result, so that this represents a process-specific value for the edge shape. Its interpretation is possible by calibration with workpieces with known properties or by theoretical calculation of the arrangement.

The arrangement has at least one light source 4 with a collimator or a laser or a beam focusing, a beam splitter mirror 7, a lens or another focusing arrangement 8, for example Fresnel lenses, concave mirrors or holographic lenses, which also changes the beam direction can be, as well as a light-sensitive transducer 11. The converter 11 can, for example, have a simple photodiode, a four-quadrant photodiode or a photodiode with more than four mutually independent light-sensitive measuring surfaces or a CCD chip. These components can also be designed as a photo transistor or photo resistor. A secondary electron multiplier or other highly sensitive photon detector can also be used.

The light emerging from the light source 4 is collimated. Due to the subsequent focusing, the beam can pass through a focus point 12 before reaching the beam splitter 7. A pinhole 6 can optionally be introduced into this focal point 12, which eliminates the insufficiently collimated parts from the beam. The aperture can be reduced independently of this with an aperture 5 that can be optionally attached. The beam then falls on the beam splitter 7. The beam strikes the lens 8 or another focusing device, while the portion 13 deflected by the beam splitter mirror 7 is directed onto an absorbent, black surface 18 or is coupled out of the measuring apparatus. If a separate detector is used to regulate the radiation power of the light source, it is preferably illuminated by this beam. The beam focused by the lens 8 then falls on the edge 9 to be measured. The angle of incidence of the beam does not necessarily have to lie in the bisecting plane of the planes forming the edge. The illuminated spot emits scattered light, which is collected by the lens 8 or another focusing device and directed onto the beam splitter 7. It is advantageous if the edge 9 is located behind the focal point of the focusing device 8 in the direction of illumination, since no real image of the edge is produced here. However, a measurement is also possible if the focus is moderate. Part of the reflected light passes through the beam splitter 7 without reflection on it and is lost for the measurement. If the edge 9 is arranged in front of the focal point of the focusing device 8, an additional focusing device 14 can be placed in the beam path after the beam splitter 7 and thus ensure an image on the detector 11. The deflected part of the beam falls on an optionally attached bandpass filter 10 which is tuned to the wavelength of the light source. As a result, light of a different wavelength is reflected or absorbed and extraneous light interference on the detector 11 behind the bandpass filter 10 is reduced. The detector 11 can be constructed as a single photodiode or as a receiver with laterally separated photosensitive surfaces. The receiver is located in or near the image plane of the image of the illuminated location of the edge 9, so that the more or less sharp image of the edge 9 comes to rest on the photosensitive surface (s). The effect that is used for the process-specific measurement of the edge shape is that a blunt edge 9, a chamfer or a breakout reflects more scattered light than from a sharp edge. A blunt edge has a larger edge radius than a sharp edge. The area of the edge that opposes the incident light vertically or inclined at a slight angle is larger with a larger edge radius, which is why a larger luminous flux is reflected. A similar behavior occurs in the event of an outbreak. Wear marks usually differ in their angle from the angle of the surface on which they are located. As a result, the measuring device can be arranged such that essentially only the reflection from the wear mark is picked up again by the measuring device. Then the incident radiation power is determined by the size of the wear mark. The radiation power incident on the detector 11 is therefore used as a measure of the edge sharpness or the presence of a chamfer, rounding, a breakout or a wear mark.

With the device described so far, a point of an edge 9 can be measured. However, since there are often breakouts, it makes sense to scan the edge 9 by tracking the optical measuring device of the edge 9. For this purpose, it is fastened laterally movable relative to the edge and the measuring device or the edge 9 is moved.

One way of achieving the tracking is to image the edge 9 on a four-quadrant diode 100 (FIGS. 2 to 4) or another detector 11 with a plurality of mutually independent photosensitive measuring surfaces. If the optical measuring arrangement is now shifted, the image 9 'of the edge 9 on the detector 11 also shifts. A prerequisite for the measurability of this process is that the image of the relevant part of the edge 9 of the detector 11 is maximal fully illuminated. Then, when the edge 9 is displaced relative to the measuring unit by the detector 11, a displacement of the image 9 'of the edge 9 can be measured. The reaction of the individual photosensitive surfaces 101, 102, 103 and 104 can be used to determine the direction in which the cutting edge 9 extends with respect to the direction of movement of the optical measuring head.

The movement can take place along or across the edge 9 (FIG. 2, FIG. 3) or a combination of these two cases (FIG. 4). The size of the illuminated spot on and around the edge 9 is adjusted by the diaphragm 5 or by changing the distance from the lens 8 so that the edge 9 on this piece can be regarded as approximately straight. The assignment between the direction of movement of FIG. 9 'of the edge 9 on the detector 11, 100 and the quadrants 101, 102, 103 and 104 results from their lateral orientation and the relative direction of movement of the measuring head with respect to the edge 9.

2, if the image 9 'of the edge 9 lies on the photodiode 100 and the relative movement of the measuring head takes place transversely to the edge 9, the image moves from the quadrants 102 and 103 to the quadrants 101 and 104 and vice versa, if the Direction of movement is opposite. If the edge 9 is rotated by 90 ° with respect to the measuring head, the image 9 'on the four-quadrant photodiode 100 also rotates by 90 ° (FIG. 3). The image then moves from quadrants 101 and 102 to quadrants 103 and 104 or vice versa with the opposite direction of movement. If the image 9 'of the edge is oriented obliquely to the quadrants 101, 102, 103 and 104, this means a combination of the two cases described above, the image of the edge 9' obliquely over the quadrants 101, 102, 103, 104 lies (Fig. 4). The shape of the photo-sensitive sensitive areas. A circular overall shape of the arrangement of the surfaces is particularly advantageous because the length of an imaged edge 9 'is approximately independent of its angular position relative to the detector, as long as it runs near the center of the four quadrants 101, 102, 103, 104. The angular position of the image of the edge 9 'then does not have to be compensated for. This is necessary, for example, for square areas.

The movement of the image of the edge 9 'can be recognized by adding the measured values of two adjacent quadrants 101, 102, 103, 104 and subtracting these two sums from one another. This represents a value for the displacement transverse to the quadrants 101, 102, 103, 104, the measurement results of which have been added. By carrying out this procedure twice with regard to the two lateral main directions, any lateral transverse movement of the edge 9 in the main directions of the quadrants 101 can be carried out , 102, 103, 104 are split. It is also particularly advantageous to divide this value by the sum of all four measured values, since the size calculated in this way for the deviation is independent of the intensity of FIG. 9 '. The detection of the transverse movement is therefore identical for sharp and blunt edges.

Values are obtained which are dependent on the lateral angular position of the quadrants 101, 102, 103, 104 in relation to the main directions of movement of the edge tracking. By rotating the diode, the direction of the movement axes can therefore be brought into agreement with the direction of the movement axes if they are at the same angle to one another as the quadrants 101, 102, 103, 104 of the diode 100. This simplifies the further regulation, since such Computational angle correction can be omitted, which also the angle of rotation between diode 100 and the direction of movement of Figure 9 'of the edge when moving against the respective axes as a calculation specification.

In the case of movement along the edge 9, no change in the measured values of the quadrants 101, 102, 103, 104 is to be expected as long as the edge 9 is imaged as a homogeneous light band 9 '. In practice, however, the edge 9 often has breakouts or other imperfections which lead to points of higher or lower intensity in FIG. 9 '. When these points pass from one quadrant 101, 102, 103, 104 to the next, this is initially just as much as a transverse movement of an edge that is oriented transversely to the really existing edge 9. The difference is, however, that in the case of breakouts during continuous displacement, only single jumps occur which are positive on one or two quadrants 101, 102, 103, 104 and negative on one or two others, while in the case of a true transverse displacement over one compared to the width a continuous change in intensity takes place over the larger distance. The location and size of outbreaks can be determined by appropriate evaluation of the measurement results, for example with electronic data processing. In this case, the software recognizes the discontinuity of the change in the incident luminous flux when moving, for example by forming the quotient from the changes in the measured radiation power and the displacement path.

The desired result of the measurement is generally the maximum radiation power reflected as scattered light, which occurs when the measuring device is moved across the edge 9. It is determined by summing the measurement results of the individual quadrants 101, 102, 103, 104. For a complete measurement of the edge 9, the measuring device must therefore be tracked in such a way that the measured points on the edge 9 form a complete row. A non-continuous measurement at individual points or sections of the edge 9 is also possible and can have advantages in the measurement have speed.

A possible procedure for the scanning is described below. First, the measuring head is roughly pre-positioned on the edge 9 or in its vicinity. By moving the positioning device and evaluating the sum of the measurement results of the quadrants 101, 102, 103, 104, it can be determined whether a maximum measurement value is reached which indicates that the center of the edge 9 has been reached. In order to meet the edge 9 with the measuring device, it is necessary to travel a predetermined distance with the measuring device in a predetermined direction. If the edge 9 has not been hit, another direction is attempted until either a clear scattered light maximum of an edge 9 has been detected or all directions have produced no result. In the latter case, the pre-positioning has to be improved, or there is no measurable edge 9, or the measuring system is not working properly. When the center of the edge is reached, the edge direction is determined. For this purpose, a step defined in direction and size is carried out in the direction of each movement axis and the resulting transverse movement of the edge 9 is measured in two directions. From the size of the two measurement results, using the formula:

Alpha = atan (result 2 / result 1)

calculate the direction of the edge with respect to the axis on which the result was obtained. It is also possible that the errors in the measurement of the transverse movement arise due to breakouts or other irregularities in the edge 9. A test step in the calculated direction should therefore be carried out to ensure that the calculation of the edge direction has given the correct result. It is advantageous to provide the width of the test step in the order of magnitude of the illumination spot. The measuring device must be in its Position after the step still measure the maximum stray light flux. For this purpose, the measuring head is moved transversely to the previously calculated edge direction and the maximum of the radiation power of the scattered light is sought again. Then it can be decided whether the direction has been calculated correctly or a correction is necessary.

In order to obtain further measurement results along the edge 9, the measuring device is shifted further in the calculated direction. The sum of the measurement results of the quadrants 101, 102, 103, 104 is used as the measurement result and it is checked whether the edge 9 has moved transversely to the direction of movement. This is possible with the procedure described above for determining the transverse movement of the edge 9. If a discrepancy is found, the direction must be determined again using the procedure described above. In addition, it must be checked every now and then whether the control keeps the measuring device on the center of the edge 9 or at the maximum of the radiation intensity of the scattered light. Just as when checking the correct calculation of the edge direction for the first time, this can be done by moving the measuring device transversely to the edge 9 and then redetermining the maximum of the radiation power of the scattered light. The interval between these tests is primarily related to the required measurement accuracy. The test is carried out after each step for maximum measurement accuracy. This corresponds to a complete scanning of the scattered light profile of the edge 9 when the measured points lie on the edge 9 without gaps. An electronic control in the form of a microcontroller can advantageously be implemented for the operations described.

Another way of determining the position of the edge 9 is to use a CCD chip on which the edge 9 is imaged. For example, an algorithm can be used to investigate whether a pixel is in the neighborhood is further illuminated. This allows the image of the edge 9 'to be digitized into its lateral positions. The edge direction can be determined from this data using linear regression, for example. When the edge 9 or the measuring device moves and the algorithm is executed repeatedly, the direction of movement can be determined. Other methods are conceivable.

Another possibility for tracking the edge 9 is to use a beam with a non-uniform, for example Gaussian intensity distribution for illumination. If the illumination is directed towards the edge 9 and the optical measuring device is moved, the reflected radiation power will decrease in the direction transverse to the edge 9, since only a weaker intensity occurs at the point with the highest reflection component. In the longitudinal direction, the difference in the process is generally smaller. On this basis, the direction of the edge can be determined by trial and error in relation to the axes of the moving device and the edge can be scanned in this direction. After a few steps, a trial-and-error procedure of the optical measuring device transversely to the edge direction is generally required again in order to compensate for bends and errors in the direction determination as well as errors in the traversing device, for example step size errors, deviation from the ideal, for example rotationally symmetrical, intensity distribution of the beam. An advantage of the variant with only one photodetector is that the scattered light falls completely on the detector 11 and that there are no inactive webs between several detector surfaces.

The process is also possible with a beam with a uniform intensity and a round beam profile. The maximum reflection arises from the effect that the edge is illuminated on a longer piece when the beam center is on the middle of the edge. Of course, a combination of round, elliptical or oval beam shape and uneven intensity distribution with a maximum is also possible.

Another possibility of scanning an edge is that the illuminating spot sweeps across the edge transversely or obliquely, while the edge and illuminating spot perform a relative movement in the edge direction. The movements can be carried out simultaneously or one after the other. The maximum values are determined as the measurement result from the data obtained in this way. These are assigned to the location of the maximum intensity of the lighting spot on the center of the cutting edge.

This procedure can be used, for example, when scanning wobbling or circular or crescent-shaped knives that are wavy in the axial direction or bent or wavy edges that are transverse to the edge or that are at an angle to the direction of advance of the illumination spot. The amplitude of the sweep is preferably so large that the point of maximum intensity of the illumination spot can reach all points on the edge.

Various principles can be used to move the lighting spot over the edge. The measuring head can be attached movably. The knife can be fixed movably across the cutting edge. The measuring head can be tilted so that the edge of the illumination spot is swept across when tilted. The tilt angles are preferably so small that the measurement errors due to the changed angle are negligible.

Tumbling circular or crescent-shaped knives or wavy, curved or sloping edges can also be measured by the lighting spot and the area from which the stray light shines the detector or detectors is steered so large that the edge does not leave the illuminated and imaged area during a relative movement between the edge and the illumination spot.

Another possibility is to deflect the light used to illuminate the edge and / or the light reflected from the edge into the measuring device by means of one or more tiltable or displaceable deflecting mirrors, thus allowing the edge to be swept over. The simplest variant is a single tiltable deflecting mirror that is positioned in front of a measuring head in which the illuminating beam passes through the same lens through which the reflected light is picked up again.

The transverse movement of the illumination spot over the edge can take place, for example, by means of vibrations at the resonance frequency, forced vibrations and / or along a guide. The drive or the vibration excitation can, for. B. by a linear electric motor or a rotating electric motor with a translation of the rotation into a longitudinal movement, for. B. by means of a spindle, a backdrop on or in a cylinder, an eccentric or a swash plate, or by electromagnetic, electrostatic or piezoelectric forces.

The frequency of the transverse movement is preferably selected with respect to the feed rate in such a way that the edge is advanced between two vibrations by the size of the illumination spot. Other frequencies that result in a complete or partial measurement of the edge can also be useful. The frequency can e.g. B. in circular knives so that the next time the edge was swept one revolution and the width of the spot was advanced. This allows the frequency of the be lowered. The frequency may vary if e.g. B. individual areas of the edge require more accurate scanning.

Another possibility of scanning circular knives is to shift the illumination spot during the rotation in the axial direction with a maximum of the size of the illumination spot in the axial direction per revolution of the circular knife. Then the parts of the z. B. added wobbling edge, which are in the respective position of the measuring head in front of the measuring head. By sweeping over the entire area of the occurring positions of the edge, the edge can be measured completely.

Analogously to this, the lighting spot can be guided several times along a wavy or inclined edge, the lighting spot being moved transversely to the cutting edge between the passages. In this way, the cutting edge can be completely grasped.

If the edge 9 is not in one plane, a further movement axis (focus axis) can be used, which moves the optical measuring device in the beam direction. A focus detector is also required which detects when the image on the detector 11 becomes out of focus. For this purpose, part of the reflected scattered light is coupled out, for example, with a beam splitter 15 (FIG. 1) and directed onto the focus detector 17. This is designed in such a way that it can recognize whether the image of the edge 9 comes to lie on or in the vicinity of the photodetector 11. The focus axis is regulated on the basis of the signal from the focus detector 17 such that the image comes to lie on the detector 11 or in its vicinity. This enables three-dimensional tracking and measurement of an edge 9 to be carried out. The focus detector 17 can be, for example, with an inclined astigmatic lens 16 and a four-quadrant diode, on which each time the focus is shifted directionally there is an oval distortion of the incident beam in the sagittal or meridional direction. The focus deviation can be determined by the difference in the sum of the radiation powers on the diagonally opposite quadrants. This is a common method in CD player technology. Another focus detection method that can be used here is the use of two prisms that refract the incident light depending on the angle of incidence. The light beam split in this way is directed onto two position-sensitive detectors (PSDs). Since the angle of the incident light is accompanied by changes in focus, their measurement results are used as a measure of the focus deviation. The output signals of the focus detector serve as a controlled variable for focus position control using the focus axis. The regulation can, for example, be carried out electronically as an analog or digital regulation. The actuator is the drive of the focus axis, which can be implemented, for example, with stepper or servo motors and a threaded spindle or with linear motors. The series of positions of the focus spot can be used to determine the three-dimensional shape of the edge course.

A further possibility of regulating the position of the focus and / or of the area which is imaged on the detector in the direction of the illumination and / or in the direction of the optical axis of the recording optics for the reflected light consists in measuring the position of the edge in the direction of the lighting and / or in the direction of the optical axis of the recording optics with other means and to regulate the relative position of the edge to the measuring device on the basis of these measurement results. In the case of separate lighting and recording optics and uniform, non-focused or weakly focused lighting, the direction of the optical axis of the recording optics is particularly relevant. When using a version with lighting and absorption of the reflected light through the same optics coincide with the optical axes.

For the controlled positioning, the edge or the measuring device can preferably be moved by means of an electric motor. A light barrier that is mechanically connected to the measuring device and that is more or less severely interrupted by the edge depending on its position can be used, for example, as the measuring means for determining the relative edge position.

It is advantageous to design the control in such a way that the illumination of the edge remains uniformly illuminated despite lateral scanning and the more or less sharp image of the illuminated point on the edge is largely completely imaged on the detector.

In a particularly advantageous embodiment, a diode laser is used as the light source 4 and a lens 8 is used as the focusing device. An aperture 5 is used to adjust the size of the lighting spot. A circular four-quadrant photodiode 100 is used as the detector. Edge tracking is controlled by a microcontroller. In addition, the entire device shown in FIG. 1 can be constructed modularly. The devices 4, 5 and 6 can be combined in a laser module, the focusing device 8 in a focusing module and the devices 10, 11 and 14 in a detection module. The focus detector 17 with the further devices 15 and 16 can also be integrated into the detection module. To control the intensity of the laser diode 4, a separate intensity module can also be provided, which for example evaluates the beams 13 deflected by the beam splitter 7. The beam splitter 7 is part of a central beam splitter module.

Claims

Patent claims

1. A method for determining the radius, the sharpness or the shape of edges, in particular cutting edges, or the presence of cutouts or the like, characterized in that an illuminating beam is directed onto the edge and the radiation power reflected by it is measured and from this the radius, the sharpness, shape of the edge or the presence or size of breakouts or wear marks is determined.

2. The method according to claim 1, characterized in that the radiation power reflected back in the direction of radiation from the edge is measured.

3. The method according to claim 2, characterized in that the reflected scattered light is coupled out by means of a beam splitter from the beam path illuminating the edge.

4. The method according to any one of claims 1 to 3, characterized in that the illuminating beam is directed onto the edge by a focusing device.

5. The method according to claim 4, characterized in that the reflected scattered light is picked up again by the same focusing device through which the illuminating beam passes.

6. The method according to any one of claims 1 to 5, characterized in that the illuminating beam is moved relative to the edge in such a way that it sweeps over the length thereof.

7. The method according to claim 6, characterized in that the edge shape is determined from the position of the points of maximum reflection.

8. The method according to any one of claims 1 to 7, characterized in that the scattered light reflected back from the intensity maximum of the illumination beam is evaluated.

8. Device for performing a method according to one of claims 1 to 7 for determining the radius, the sharpness or the shape of edges or the presence of cutouts or the like, characterized by a light source, a detector for recording the light portion reflected by the edge and Measurement of its radiation power and an evaluation device.

9. The device according to claim 8, characterized in that it has a focusing device for focusing the light beam on the edge and / or for receiving the scattered light.

10. The device according to claim 8 or 9, characterized in that the detector has at least one photodiode.

11. The device according to claim 8 or 9, characterized in that the detector has a four-quadrant photodiode, a secondary electron multiplier, an avalanche photodiode, a PIN diode or a row of diodes.

12. The device according to claim 8 or 9, characterized in that the detector has a CCD chip or another pixel matrix photodetector.

13. Device according to one of claims 8 to 12, characterized in that the detector is arranged adjustable.

14. Device according to one of claims 8 to 13, characterized in that the light source is a laser.

15. Device according to one of claims 8 to 14, characterized in that the light source and / or the edge are arranged to be movable and / or pivotable.

16. Device according to one of claims 8 to 15, characterized in that _y the diameter of the illuminating beam or of the focus spot in the beam path can be varied after the focusing device.

17. Device according to one of claims 8 to 16, characterized in that the evaluation device controls the relative movement of the light source and edge and / or the distance between the light source and edge and / or the adjustment of the beam diameter depending on the measurement signals of the detector.

18. Device according to one of claims 8 to 17, characterized in that it has a further detector for regulating the intensity of the light source.

19. Device according to one of claims 8 to 18, characterized in that an aperture is arranged in front of the detector.

20. Device according to one of claims 8 to 19, characterized in that it is of modular construction and has at least one laser module, one objective module and one detector module.

21. The apparatus according to claim 20, characterized in that it also has a beam splitter module.

22. The apparatus according to claim 21, characterized in that the other modules are attached to the beam splitter module.

23. Device according to one of claims 20 to 22, characterized in that it additionally has an intensity module for regulating the intensity of the laser module.

24. Device according to one of claims 20 to 23, characterized in that the objective module contains a microscope objective.

25. Device according to one of claims 20 to 24, characterized in that the detection module contains at least one photodetector.

26. The apparatus according to claim 25, characterized in that the detection module also has a focusing device, an aperture and a filter.

27. Device according to one of claims 20 to 26, characterized in that the laser module has a correction cylindrical lens or prisms for correcting the beam profile.