EP3583382A1 - Method for the non-destructive analysis and classification of a metal workpiece - Google Patents
Method for the non-destructive analysis and classification of a metal workpieceInfo
- Publication number
- EP3583382A1 EP3583382A1 EP18707233.5A EP18707233A EP3583382A1 EP 3583382 A1 EP3583382 A1 EP 3583382A1 EP 18707233 A EP18707233 A EP 18707233A EP 3583382 A1 EP3583382 A1 EP 3583382A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- workpiece
- determined
- intensity
- roughness
- reflection intensity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
- G01B11/303—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces using photoelectric detection means
Definitions
- the present application relates to a method for non-destructive examination and classification of a metallic workpiece by means of scattered light measurement, using a radiation source, a detector having a sensor and a signal and / or data technology connected to the sensor evaluation and control unit, wherein the workpiece of the irradiation the radiation source is exposed at an angle of incidence and the radiation backscattered from the workpiece at a plurality of failure angles is detected by the detector unit as a scattering angle dependent reflection intensity, and from the data thus acquired, scattering angle dependent roughness values are determined.
- contact measurements are used to characterize metallic surfaces in terms of roughness and topography, such as contact profilers or atomic force microscopes.
- investigation methods are only insufficiently suitable for in-line product monitoring in production units and / or transport lines, since they lack the required heat resistance and impact resistance.
- such methods are costly and require relatively long acquisition times, so are not suitable for rapid quality control.
- Non-contact imaging techniques based on camera techniques to characterize surface appearance are also known. These methods are based on the analysis of image gradients. Examples include GLGCM (Gray Level Gradient Co-Occurrence Matrices) or GOCM (Gradient Only Co-Occurrence Matrices). Although such methods are generally suitable for the determination of surface patterns such as stripes and grooves, however, the significance of microstructural and topographical material properties is lacking.
- the measuring method of the scattered light measurement is also suitable for the examination of metallic surfaces.
- scattered light measurements have hitherto been used for the investigation of shiny and polished metal surfaces.
- the method of scattered light measurement is suitable for the determination of microstructural surface properties such as roughness, topography, color and appearance.
- the method of angle-resolved light scattered measurement (ARS) is to be mentioned as a relevant method.
- a section of the surface to be examined is irradiated with a light source, for example an LED, with a light beam at a defined angle of incidence.
- the angle of incidence may be for example 90 °.
- the suitability of the method of scattered light measurement for the characterization of workpiece surfaces is basically known (Brodmann, R. Allgauer, Comparison of light scattering from rough surfaces with optical and mechanical profilometry, Proc. Int., Congress on Optical Science and Engineering, p. 1 11-1 18, International Society for Optics and Photonics, 1989), however, lacks this in defined process and classification steps and the correlation of the measured parameters with the final requirements of the manufactured workpiece.
- the invention is therefore based on the invention to provide a method for non-destructive examination and classification of metal workpieces, with which the quality of the workpieces with respect to the quality requirements for surface properties on the parameters obtained from scattered light measurements determined and the workpieces can be classified in this regard.
- this involves a method for the non-destructive examination and classification of a metallic workpiece by means of scattered light measurement, using a radiation source, a sensor comprising a detector unit and an evaluation and / or data-related evaluation and evaluation unit A control unit, wherein the workpiece is exposed to irradiation by the radiation source at an angle of incidence, and the radiation backscattered from the workpiece at a plurality of failure angles is detected by the detector unit as scatter angle dependent reflection intensity, and from the data thus acquired, scattering angle dependent roughness values are determined.
- the procedure uses the following steps. a) on the basis of series of experiments, determining setpoint ranges of the reflection intensity and the roughness values,
- step f) making a negative determination including termination of the method, if the standard reflection intensity is outside of the setpoint range after step a), g) determining an intensity difference from the maximum and the minimum of a data set of reflection intensities, wherein the data set consists of reflection intensities recorded in a plurality of individual measurements and classifying the workpiece as being within, outside, or within the limits of a predetermined intensity range by comparing the determined intensity difference with intensity differences previously determined at reference workpieces.
- the radiation source and the sensor together with the detector unit in a single component, for example to be arranged in one and the same housing.
- a separate arrangement of the radiation source and the sensor is possible.
- the decisive factor is that the workpiece to be examined is exposed at an angle of incidence to a light beam emitted by the radiation source.
- the arrangement of the sensor or the detector unit is such that the backscattered radiation from the workpiece can be detected by the detector unit.
- the workpiece can lie completely or partially in an incident plane of the light beam emitted by the radiation source.
- the Arrangement of the workpiece can be done plane parallel or angled relative to the plane of incidence. A completely parallel arrangement of the workpiece or of an examination area irradiated by the light beam relative to the plane of incidence or radiation source can not be completely fulfilled, even on account of surface irregularities of the workpiece.
- the setpoint ranges are calculated from averaged data of a plurality of measurement points and a plurality of workpieces. Even with each individual measurement, light from the different spatial positions of the irradiated area of the workpiece is reflected back in each case with different reflection intensities as a function of the angle of incidence and reflection, and detected by the detector unit. Even with only a single measurement, a plurality of measuring points is recorded, from which the setpoint ranges of the reflection intensity and the roughness values can be determined.
- the individual measurement can also be repeated at one and the same location point or irradiated area or in addition to other location points of the workpiece in order, for example, to reduce measurement errors.
- the setpoint ranges of the reflection intensity and the roughness values can then be determined for example from mean values of the individual measurements and / or of the individual location points.
- a calculation of the setpoint ranges from measuring points of a plurality of workpieces additionally reduces the error susceptibility of the method. Furthermore, production-related inhomogeneities of the workpieces are averaged out.
- the standard roughness and standard reflection intensity are averages of a plurality of individual values.
- the individual values can reflect reflection values or roughness values which correspond to the values at different failure angles, that is to say the reflection intensities respectively measured at different detector positions and the roughness values determined therefrom.
- the individual values thus output a data record representing the irradiated area of the workpiece.
- These data can be averaged to a single value of the reflection intensity, ie a standard reflection intensity and from this the standard roughness can be determined.
- distribution functions of the reflection intensities can be used for the evaluation, and with the help of which the roughness values and / or the standard roughness can be calculated.
- individual values of several different irradiated areas of the workpiece can also be used for the evaluation.
- the standard reflection intensity from the according to step b) of the method according to claim 1 measured scattering angle-dependent reflection intensity can be determined, in particular by averaging.
- the standard reflection intensity can average as a representative value manufacturing-related, local inhomogeneities of the workpiece surface.
- the standard roughness is determined from the scatter angle-dependent reflection intensity measured according to step b) of the method according to claim 1, in particular from its distribution function. Also based on the roughness values thus measuring errors are reduced.
- the radiation source is an LED. Such radiation sources are particularly inexpensive and easily replaceable. With such an LED, the workpiece is irradiated with a light beam of a certain diameter at an angle of incidence. However, other sources of radiation such as light bulbs or lasers as a radiation source for the inventive method into consideration.
- the detector unit is formed from a plurality of individual detector diodes.
- the light which is backscattered to different spatial positions of the irradiated workpiece region can be detected and detected over a wide range.
- records of reflection intensities representing the irradiation area of the workpiece can be recorded via the multiplicity of individual detector diodes.
- the senor and the radiation source are arranged to be movable. As a result, different positions of the workpiece can be irradiated and examined in a simple manner.
- the setpoint ranges of the reflection intensity and the roughness values are determined from test series of single or multiple measurements on a multiplicity of individual workpieces, a multiplicity of values being recorded for each single or multiple measurement.
- a multiplicity of values being recorded for each single or multiple measurement.
- a number of different, optionally preselected workpieces are irradiated at one or more locations and the angle-dependent reflection intensity is measured. From this, roughness values can then be calculated.
- a variety of values are recorded, corresponding to the different backscatter angles.
- an important advantage of the method according to the invention is that it is an in-line method of quality control and the radiation source and the sensor are arranged within or in proximity to a production unit and / or transport line. This makes it possible to automate the workpieces manufactured in a manufacturing unit and / or conveyed by a transport line and to check whether they meet the quality requirements. A separate, possibly manual examination step is thus avoided.
- the examined workpiece is sorted out of the production unit and / or transport line in a negative determination in step d) or f) of the method according to claim 1.
- a sorting out of the production flow is ensured. This leads to an increase in quality standards and verification certainty.
- the inventive method for strip and / or pattern recognition on the surface of the examined workpiece can be suitable. The results can be included in the quality assessment.
- FIG. 1 Schematic structure of the scattered light measurement for the invention
- Fig. 2 Process schematic of the method according to the invention.
- a radiation source 2 and a sensor in particular a scattered light sensor
- a radiation source 2 or a scattered light sensor can be arranged inside or in proximity to a production unit and / or a Transport line are arranged.
- the radiation source 2 and the sensor positionally fixed, ie stationary, or arranged to be movable. The latter can be realized by attachment to a suitable transport carriage.
- the radiation source 2 and the sensor together with its detector unit 3 can be arranged in one and the same housing and thus form an integrated component.
- the metallic workpieces 1 moved by the production unit and / or transport line are stopped as soon as they are in the vicinity of the radiation source 2 and the sensor together with its detector unit 3. This ensures a temporarily stationary position of the workpiece is ensured relative to the radiation source 2 and the sensor. Then the respective workpiece 1 can be examined. For this purpose, measurements can be made on different areas of the workpiece, either by the radiation source 2 and the sensor for the respective individual measurements relative to the fixed position workpiece or the workpiece is moved relative to the fixed position radiation source and the positionally fixed sensor. As FIG. 1 shows by way of example, the workpiece is irradiated at each individual measurement at a defined angle of incidence ⁇ by a light beam of a diameter d emitted by the radiation source 2.
- the detector unit 3 comprises a plurality of individual detector diodes 5, which detects the backscattered light at n different detector positions ⁇ , '.
- the radiation source 2 is designed such that it irradiates the workpiece 1 to be examined with light or a light beam of a suitable wavelength at a fixed or variably adjustable angle of incidence. In particular, an LED as the radiation source 2 is suitable for this purpose.
- the detector unit 3 preferably consists of a diode array, ie a plurality of individual diodes 5 arranged side by side or in proximity to one another.
- the radiation source 2 and the detector unit 3 of the sensor are arranged at a distance from the workpieces 1 to be examined, whereby the basic condition of a non-contact, non-destructive measurement is ensured.
- angle-dependent reflection intensities are detected with the detector unit 3 of the sensor or scattered light sensor.
- the sensor and also also the radiation source 2 interact with signal and / or data technology with an evaluation and control unit.
- the determined data can be stored or buffered and compared with other data.
- the evaluation and control unit also interacts with the production unit and / or transport line and ensures their smooth operation, taking into account the scattered light measurements to be performed.
- this means that the method according to the invention is adapted in terms of time to the requirements and the operation of the production unit and / or transport line.
- the workpiece 1 is sorted out or further transported after appropriate evaluation by the evaluation and control unit.
- the sensor technology is closely linked to the production unit and / or the transport line by the evaluation and control unit.
- step a) first of all necessary in series of experiments target value ranges ⁇ l m, AAQ m l m of the reflection intensity and the roughness Aq m to be determined.
- the calculation is made by the above-mentioned and generally known metrological and mathematical relationships between the reflection intensity and the optical roughness.
- the decisive factor is that the setpoint ranges ⁇ 1 m , ⁇ q m of the reflection intensity l m and the roughness values Aq m in the context of the invention are calculated from averaged data of a multiplicity of measuring points and a multiplicity of workpieces 1. Even during a single measurement, a certain spatial or areal area of the respective workpiece 1 is examined.
- the target value ranges ⁇ l m For each individual measurement, a large number of different measuring points are already recorded. Furthermore, can be used AAQ m measured at several different locations of a workpiece 1 reflection intensities I and averaged to determine the target value ranges ⁇ l m. For example, about reflection intensities of the backscattered radiation from different areas of the workpiece, which are each irradiated and examined in individual measurements. Importantly, the target value ranges ⁇ l m to determine ⁇ Aq m measured at a variety of different workpieces 1 of each to be examined workpiece genus to minimize manufacturing or metrology errors.
- the target value ranges ⁇ l m, AAQ m carry out by measurements on such workpieces that have been previously evaluated by experts by visual inspection as the quality required of the surface fulfilling, or which lie in predefined threshold ranges for the quality requirements.
- upper and lower limits of the respective parameters can be determined depending on the expert evaluation.
- the setpoint ranges ⁇ l m , AAq m can be stored and stored in the evaluation and control unit.
- the data of the setpoint ranges ⁇ l m , AAq m may be stored on an external server, which is connected via a data and / or signal connection to the evaluation and control unit.
- the data of the setpoint ranges ⁇ l m , AAq m can be stored, for example, as a function of the location, the failure angle ⁇ , or the diode number. It is possible to update the data of the setpoint ranges ⁇ l m , AAq m in periodic or aperiodic time intervals, to supplement or to replace them by new parameter sets. Depending on the production unit, it may be necessary, for example, to exchange the parameter sets if critical production parameters are changed or other workpieces are manufactured in the same system.
- the radiation source and the scattered light sensor may also be advantageous to make the radiation source and the scattered light sensor portable, so that it can be used flexibly in various production plants and / or transport lines. Even then, it is essential to set point ranges ⁇ l m, m AAQ reflection intensity I m and the roughness Aq m adapted accordingly.
- the scatter angle-dependent reflection intensities I of the respective workpiece 1 to be examined are measured by the sensor.
- Each data set of the reflection intensities I is based on angle-dependent individual intensities, corresponding to the different spatial positions of the exposure area of the light beam 6 of the diameter d incident on the workpiece 1 from the LED.
- a standard roughness Aqs is determined from the measured reflection intensities I. This is a purely optically determined roughness value.
- the standard roughness Aqs is an average of a plurality of individual values, for example determined from the location-dependent and scatter angle-dependent measured reflection intensities I of different spatial positions of the exposure area.
- other averaging methods are also conceivable, for example the averaging of the reflection data I from different exposure areas of a workpiece with subsequent roughness determination.
- step d If the determined standard roughness Aqs lies outside the setpoint value range ⁇ Aq m of the roughness values Aq m previously determined or stored in the evaluation and control unit, a negative determination is made by the sensor or the evaluation and control unit (step d)) and the examination method for the respective workpiece completed.
- the workpiece is sorted out and removed or not released from the production unit and / or transport line.
- a standard reflection intensity ls is determined from the measured reflection intensities I according to step e).
- the standard reflection intensity ls is an average of a plurality of individual values, for example, determined from the location-dependent and scatter angle-dependent measured reflection intensities of different spatial positions of the illuminated by the LED portion of the workpiece 1. Is the determined standard reflection intensity ls outside the previously determined or stored in the evaluation and control unit Setpoint range of the reflection intensity l m , a negative determination is made by the sensor or the evaluation and control unit (step f)) and the examination process for the respective workpiece finished. The workpiece is sorted out and removed from the production unit and / or transport line or not released.
- the workpiece 1 is finally classified, see step g) of the process scheme in FIG. 2.
- a predefinable subregion of the workpiece 1 is examined which is larger than the pure exposure range d of the light beam emitted by the radiation source or LED.
- the radiation source 2, the detector unit 3 of the sensor and the workpiece 1 are positioned and moved relative to each other such that the light beam 6 reaches different positions of the workpiece 1 and thus scattered light measurements can be made at various points.
- a surface profile of the reflection intensities I can be detected.
- the reflection intensities I of the individual measurements thus obtained can be combined to form a combined location profile or spatially resolved profile of the reflection intensities.
- the difference intensity difference ⁇ between the maximum and the minimum reflection intensity is determined according to the invention.
- the value ⁇ determined for the respective workpiece is compared with predetermined reference to workpieces or intensity differences determined therefrom predetermined desired values so ⁇ l n. These setpoints are so ⁇ l n determined with the same procedure of spatially resolved reflectance intensity profiles of reference workpieces. Only those reference workpieces are used for the intensity measurements, which were previously assessed by visual inspection as having fulfilled the quality requirements for the surface by experts.
- the evaluation is provided that the intensity difference ⁇ than outside the desired intensity range so ⁇ l n lying, the workpiece from the production unit and / or transport line is rejected.
- the workpieces 1 may be separate from the production unit or transport line and stored, but may be provided in these samples, an additional human visual inspection or Make a visual check before finally sorting out the workpieces.
- the workpiece 1 to be examined can be examined, evaluated and classified with regard to its surface properties such as patterns and / or stripes. Depending on the quality requirements, the workpiece can be sorted out or released.
- the measurements form the basis of the stripe and / or pattern recognition.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102017103037.9A DE102017103037A1 (en) | 2017-02-15 | 2017-02-15 | Method for non-destructive examination and classification of a metallic workpiece |
PCT/DE2018/100109 WO2018149447A1 (en) | 2017-02-15 | 2018-02-08 | Method for the non-destructive analysis and classification of a metal workpiece |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3583382A1 true EP3583382A1 (en) | 2019-12-25 |
Family
ID=61282941
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP18707233.5A Withdrawn EP3583382A1 (en) | 2017-02-15 | 2018-02-08 | Method for the non-destructive analysis and classification of a metal workpiece |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP3583382A1 (en) |
DE (1) | DE102017103037A1 (en) |
WO (1) | WO2018149447A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN116379927B (en) * | 2023-05-31 | 2023-08-29 | 湖南隆深氢能科技有限公司 | Accurate detection method and system applied to laminating production line and storage medium |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19824623A1 (en) * | 1997-07-19 | 1999-02-11 | Univ Ilmenau Tech | Technical surface characterisation device |
WO2000022377A1 (en) | 1998-10-08 | 2000-04-20 | Daimlerchrysler Ag | Measurement of small, periodic undulations in surfaces |
DE102012005417B4 (en) * | 2012-03-14 | 2013-10-24 | Friedrich-Schiller-Universität Jena | Apparatus and method for angle-resolved scattered light measurement |
DE102012011588A1 (en) * | 2012-06-06 | 2013-12-12 | Forschungszentrum Jülich GmbH | Method for controlling and determining the properties of light-scattering surface textures and for regulating the production process of light-scattering surface textures |
DE102015106738A1 (en) | 2015-04-30 | 2016-11-03 | Brodmann Technologies GmbH | Method for contactless assessment of the surface condition of a ball track of a ball screw |
-
2017
- 2017-02-15 DE DE102017103037.9A patent/DE102017103037A1/en not_active Withdrawn
-
2018
- 2018-02-08 WO PCT/DE2018/100109 patent/WO2018149447A1/en unknown
- 2018-02-08 EP EP18707233.5A patent/EP3583382A1/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
WO2018149447A1 (en) | 2018-08-23 |
DE102017103037A1 (en) | 2018-08-16 |
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