DE102022204371A1 - Device for checking the curing condition of KTL coated components - Google Patents

Abstract

What is described is a device for testing the degree of crosslinking of a coating hardened by a crosslinking process on components in a production line, wherein a fluorescence wavelength of the coating emitted under UV light depends on the degree of crosslinking.

Description

The invention relates to a device for testing the degree of crosslinking of a coating hardened by a crosslinking process on components in a production line, the coating preferably being a KTL coating.

In industrial production, components are often painted. A paint is applied to the component and then hardened, for which the applied paint is typically subjected to a crosslinking process. The checking of the cross-linking of the paintwork is usually carried out destructively on individually selected or statistically selected components.

Such offline control is also time-consuming. The delayed detection of possible errors during the curing of the coating is disadvantageous, especially if components are coated in a production line.

The conditions for crosslinking a paint, such as time and temperature, are determined using empirically determined parameters. Variations of different components in terms of geometry, e.g. in terms of weight and surface, are often not taken into account.

For the crosslinking of a paint, a certain component temperature is required over a certain time. Different component geometries or masses lead to different surface temperatures with the same oven parameters, in particular temperature and time, due to the different masses and surface conditions. This means that variations in the networking state can occur. Furthermore, different positions and loads within the oven also lead to deviations. Individual temperature adjustment is not practical today.

A frequently used painting process is cathodic dip painting (KTL painting). When crosslinking KTL paints and other paints, the frequency of the fluorescent radiation emitted under UV light changes.

The object of the present invention was therefore to provide a device for testing the degree of crosslinking of a coating on components hardened by a crosslinking process, with which the disadvantages described above can be overcome. In particular, the task was to provide a device with which a non-destructive and automatic test of the degree of crosslinking of the coating can be carried out. It should also be possible to carry out the exam online and in real time. In addition, the device should also enable automatic control of the crosslinking process for the coating.

The solution to the problem is based, among other things, on the knowledge that when crosslinking coatings, in particular KTL paints, the frequency of the fluorescent radiation emitted under UV light irradiation changes depending on the degree of crosslinking. This change in the frequency of the fluorescent radiation emitted under UV light irradiation as a function of the degree of crosslinking and a corresponding method as well as related examples are described in detail in the DE 102020203343 A1 described, which is hereby referred to.

A device based on this effect was developed to control the degree of crosslinking of coatings on components. UV is short for ultraviolet.

1. a) eine UV-Lichtquelle zur Beleuchtung der Beschichtung auf mindestens einem der Bauteile,
2. b) ein Digitalkamerasystem zur Aufnahme mindestens eines Bildes der mit der UV-Lichtquelle beleuchteten Beschichtung,
3. c) ein Bildverarbeitungsprogramm zur Auswertung der Bilddaten des oder der aufgenommenen Bilder auf Basis einer vordefinierten Bewertungsskala für den Vernetzungsgrad der Beschichtung, die mindestens eine Klassifizierung in eine angemessene Vernetzung und eine nicht angemessene Vernetzung aufweist, auf deren Basis die Auswertung erfolgt,
4. d) eine Ausgabeeinheit und/oder eine Steuerungseinheit zur Steuerung von mindestens einer der folgenden Maßnahmen auf Basis der von dem Bildverarbeitungsprogramm erhaltenen Auswertung:
   • i) Ausschleusen von Bauteilen aus der Produktionslinie, die gemäß der Auswertung eine nicht angemessene Vernetzung der Beschichtung aufweisen, wobei die ausgeschleusten Bauteile verworfen oder einer Nachvernetzung für die Beschichtung unterworfen werden können,
   • ii) Einstellen mindestens eines Parameters für den Vernetzungsprozess zur Aushärtung der Beschichtung.

The invention thus relates to a device for testing the degree of crosslinking of a coating hardened by a crosslinking process on components in a production line, wherein a fluorescence wavelength of the coating emitted under UV light depends on the degree of crosslinking, the device comprising

1. a) a UV light source for illuminating the coating on at least one of the components,
2. b) a digital camera system for recording at least one image of the coating illuminated with the UV light source,
3. c) an image processing program for evaluating the image data of the recorded image or images based on a predefined evaluation scale for the degree of crosslinking of the coating, which has at least one classification into appropriate crosslinking and inappropriate crosslinking, on the basis of which the evaluation is carried out,
4. d) an output unit and/or a control unit for controlling at least one of the following measures based on the evaluation received from the image processing program:
   • i) Rejecting components from the production line which, according to the evaluation, do not have adequate cross-linking of the coating, whereby the rejected components can be discarded or subjected to subsequent cross-linking for the coating,
   • ii) Setting at least one parameter for the crosslinking process to cure the coating.

The device according to the invention can be used for quality control and/or for process control of the coating process.

• - Zerstörungsfreie Prüfung des Aushärtegrades anstatt einer zerstörenden Prüfung
• - bei Bedarf Prüfung der ganzen Serie von beschichteten Bauteilen und nicht nur einem Teil davon
• - Online-Kontrolle und -Protokollierung des Aushärtegrades in Echtzeit möglich anstatt der heute üblichen zeitaufwändigen Offline-Kontrolle
• - Online-Verfolgung des Aushärteprozesses zur Prozessoptimierung und Verringerung des Ausschusses
• - Online Prozessüberwachung, -regelung und -anpassung (Closed Loop) möglich
• - Minimierung der durch eine fehlerhafte Aushärtung erzeugten Fehlerrate
• - Variable Prozessführung bezogen bzw. abhängig von der Bauteilgeometrie möglich.

The advantages of the device according to the invention are in particular:

• - Non-destructive testing of the degree of hardening instead of a destructive test
• - If necessary, testing the entire series of coated components and not just a part of them
• - Online control and logging of the degree of hardening possible in real time instead of the time-consuming offline control that is common today
• - Online tracking of the curing process to optimize the process and reduce waste
• - Online process monitoring, control and adjustment (closed loop) possible
• - Minimizing the error rate caused by incorrect curing
• - Variable process control related or possible depending on the component geometry.

The device according to the invention for testing the degree of crosslinking of a coating hardened by a crosslinking process on components in a production line is described in detail below.

A production line is a production system in which several processing stations are connected to produce a product according to the line principle. The production line here includes in particular the application of the coating to the components and the crosslinking of the applied coating as well as, if necessary, further processing of the coated components.

The coating is a crosslinkable coating in which a fluorescence wavelength of the coating emitted under irradiation with UV light depends on the degree of crosslinking. It is further preferred that the change in the fluorescence wavelength emitted under UV light appears in the visible range. Crosslinking hardens or hardens the coating.

The coating is usually an organic coating. The organic coating is preferably an electrophoretically deposited coating, in particular a KTL coating. The coating can also be, for example, a powder coating. As already stated, a KTL coating is applied by cathodic dip painting (KTL), which is generally known to those skilled in the art. The coating can optionally also be applied in another way, for example by spraying.

The crosslinking of the applied coating, in particular a KTL coating, can be carried out in the usual way, for example by means of UV irradiation or heating, for example in an oven, with thermal crosslinking being preferred. The crosslinking temperature depends on the coating used. The crosslinking of KTL coatings can take place, for example, at a temperature in the range of 180 to 210 °C.

The coating applied to the component contains binders, in particular organic binders, the crosslinking of which leads to the hardening of the coating. Examples of binders in the coating, in particular KTL coatings, are, for example, epoxy resins, in particular epoxy resin-amine adducts, or blocked isocyanates.

The device according to the invention comprises a) a UV light source for illuminating the coating on at least one of the components. Industrial-grade UV lamps can be used as a UV light source. One or more UV lamps can be used as a UV light source. The UV light source or UV lamp preferably emits UV light with a wavelength in the range from 315 to 380 nm.

The device according to the invention further comprises b) a digital camera system for recording at least one image of the coating illuminated with the UV light source. The digital camera system may include one or more digital cameras. Industrial-grade digital cameras can be used.

It is understood that the digital camera is sensitive to the wavelength range in which the fluorescence wavelength of the coating emitted under UV light, which depends on the degree of crosslinking, lies. As mentioned, it is preferred that the fluorescence wavelength of the coating emitted under UV light, in particular its change, appears in the visible range. The visible range lies in a wavelength range from approximately 380 nm to 780 nm.

The digital camera or cameras of the digital camera system are preferred for image recognition and adapted to the color spectrum of UV light.

The device according to the invention or its digital camera system can be configured to record at least one image of a single coated component or a partial area of the coated component or at least one image of a plurality of coated components for testing the degree of crosslinking of the coating.

The test can therefore be carried out on individual coated components. All coated components created in the production line can be tested one after the other or only selected coated components can be tested. It is also possible to take a picture of several coated components, e.g. of all components that are on a frame, or of several components that are arranged one behind the other on a conveyor device. The image data of the several components on the recording can then be analyzed separately by the image processing program.

The device according to the invention further comprises c) an image processing program for evaluating the image data of the recorded image or images based on a predefined evaluation scale for the degree of crosslinking of the coating, which has at least one classification into appropriate crosslinking and inappropriate crosslinking, on the basis of which the evaluation is carried out . Adequate networking can be described as “okay” (OK) and inadequate networking as “not OK” (NOK).

The evaluation obtained is output by the image processing program, in particular to the output unit and/or the control unit.

The image processing program is software that is installed in a computing unit, for example a computer. The image processing program is created using an industrial-grade image processing library, which is then used to evaluate the image data received from the digital camera system using a predefined evaluation scale.

In a preferred embodiment of the device according to the invention, the image processing program for evaluating the image data is based on an AI system (AI = artificial intelligence). The evaluation with an AI system can be based, for example, on machine learning or deep learning based on neural networks.

The evaluation of the image data of the recorded image(s) in the image processing program is carried out on the basis of a predefined evaluation scale for the degree of crosslinking of the coating, which has at least one classification into appropriate crosslinking and inappropriate crosslinking. The predefined rating scale therefore has at least two levels that reflect appropriate networking and inappropriate networking. The levels can be defined as required.

The predefined rating scale can also contain more than two levels, e.g. contain three or more than three levels. Just as an example, an evaluation scale with 3 levels can be used, e.g. a level 1 for a degree of networking below 85% (inappropriate networking), a level 2 for a degree of networking of 85 to 95% and a level 3 for a degree of networking above 95% (adequate networking). include. In this way, a finer assessment of the crosslinking state of a coating can be achieved, whereby additional information can be obtained, which, for example, enables a more detailed assessment of the crosslinking process and an adjustment of the parameters of the crosslinking process. The actual values for the steps obviously depend on the type of coating and the desired degree of crosslinking.

The levels of the predefined rating scale may also include a level for a “burnt” condition of the coating. The overburned state means a coating in which the crosslinking process has taken place over too long a period of time and/or at too high a temperature, which leads to the already adequately crosslinked coating thermally decomposing again. The decomposition processes can be detected by a change in the wavelength of fluorescence emitted by the coating under UV light.

In one embodiment, the evaluation of the image data of the captured image(s) may include an instruction for maintaining or changing at least one parameter that is relevant to the networking process, determined by analysis using the rating scale. For this purpose, it can be useful if the rating scale includes several levels, for example at least three, such as three or more than three levels.

The evaluation scale can alternatively or additionally have a classification of the degree of crosslinking of the coating depending on at least two sub-areas of the coating. A location-dependent assessment of the degree of crosslinking of the coating can be achieved. For example, two different areas of the coating can be evaluated based on the rating scale.

In this way it can be determined whether the different areas examined have the same or different levels of networking. This can be used, for example, to achieve a more precise evaluation of the average degree of crosslinking of the coating. This can also be useful if the evaluation of the image data of the captured image(s) is intended to include an instruction for maintaining or changing at least one parameter that is relevant to the networking process, determined by analysis using the rating scale.

If an image is taken of several coated components, the image processing program can evaluate the respective components separately using the predefined rating scale.

The predefined evaluation scale is created in particular with the help of reference coatings, in particular reference KTL coatings, for which the degree of crosslinking is known. It is understood that the reference coating is the coating whose degree of crosslinking is to be examined in the production line using the device according to the invention.

Images of the reference coatings illuminated with a UV light source, the degree of crosslinking of which is known, are recorded with a digital camera system in order to obtain image data of the reference coatings. The image data of the reference coatings with known degrees of crosslinking are then used to create the predefined rating scale, which is made available to the image processing program.

The reference coatings can be applied to the components that are later to be tested using the device according to the invention. As a rule, however, it is sufficient that the reference coatings are applied to any substrate. Simple flat bodies, for example a metal substrate such as a sheet of metal, are suitable as a substrate. Otherwise, it is preferred to record the images of the reference coating under the same or similar conditions as those present later when testing the degree of crosslinking in the production line with the device according to the invention, e.g. with regard to UV light source, distance to UV light source, brightness of the room etc.

The degree of crosslinking of the reference coatings can be determined using known analysis methods that involve destruction of the sample to be tested. Examples of suitable methods are differential scanning calorimetry (DSC), MEK test, thermogravimetry (TG) or infrared (IR) analysis. The DSC test, for example, determines the amount of heat given off or absorbed by a sample during heating, cooling or an isothermal process, which indicates the degree of crosslinking.

It goes without saying that for each level of the predefined evaluation scale there must be at least one reference coating with a corresponding degree of crosslinking. It may be useful to take images of multiple reference coatings for each stage to increase accuracy. The number required may depend, for example, on the respective level and the desired accuracy. For example, 1 to 30, preferably 2 to 25, more preferably 3 to 20 reference coatings can be tested for each level of the predefined evaluation scale.

• i) Ausschleusen von Bauteilen aus der Produktionslinie, die gemäß der Auswertung eine nicht angemessene Vernetzung der Beschichtung aufweisen, wobei die ausgeschleusten Bauteile verworfen oder einer Nachvernetzung für die Beschichtung unterworfen werden können,
• ii) Einstellen mindestens eines Parameters für den Vernetzungsprozess zur Aushärtung der Beschichtung.

The device according to the invention further comprises d) an output unit and/or a control unit for controlling at least one of the following measures based on the evaluation received from the image processing program:

• i) Rejecting components from the production line which, according to the evaluation, do not have adequate cross-linking of the coating, whereby the rejected components can be discarded or subjected to subsequent cross-linking for the coating,
• ii) Setting at least one parameter for the crosslinking process to cure the coating.

In one variant, the device has an output unit for controlling said at least one measure i) and/or ii) based on the evaluation received from the image processing program. The output unit can be a common output device, e.g. a screen. The evaluation can be reproduced on the output unit in the form of information and/or instructions that an operating personnel can implement. The information/instruction can include, for example, that the coating on the respective component does not have adequate crosslinking and that the component must be discarded or subjected to subsequent crosslinking, or that the degree of crosslinking is still within the tolerance range, but a change in a parameter of the crosslinking process, e.g temperature, should take place.

In a preferred variant, the device has a control unit for controlling said at least one measure i) and/or ii) based on the evaluation received from the image processing program.

The control unit has at least one input for receiving the evaluation determined by the image processing program and at least one output for outputting actuator signals. The actuator signals can be used to set one or more parameters of the networking process, for example temperature or duration, and/or to control corresponding devices, such as robots, which, for example, cause selected components to be removed from the production line and transported for disposal or subsequent networking. The control unit can be based on one or more microprocessors or microcontrollers, which are installed, for example, in a computing unit, such as a computer. The control unit can have an output unit as a human-machine interface. The control unit can be, for example, a programmable logic controller (PLC). The image processing program or parts thereof can optionally be integrated in the control unit.

It is particularly preferred that the device according to the invention has the control unit mentioned, since this enables fully automatic operation in real time. As a rule, it is expedient for the device to contain the output unit in addition to the control unit. This allows automatic operation to be controlled.

Measure i) involves removing components from the production line that, according to the evaluation, do not have adequate crosslinking of the coating. The rejected components can be discarded or subjected to post-crosslinking for the coating.

The components can be removed and transported for disposal or subsequent networking by operating personnel or, preferably, by appropriate devices such as robots or conveyor devices. The devices mentioned can be controlled by the control device

Measure ii) includes setting at least one parameter for the crosslinking process to harden the coating. The parameters to be set can be, for example, the temperature, the duration or the positioning of the component or components when crosslinking the coatings on them. This can be done by operating personnel. Such a setting is preferably carried out by the control unit.

The image processing program can provide a corresponding evaluation based on the level of the evaluation scale determined for the respective component. For example, if a stage with inadequate crosslinking is determined, the evaluation may include an instruction to change a parameter of the crosslinking process, e.g. with regard to temperature and/or duration. If the predefined rating scale has several levels that enable a more precise determination of the degree of networking, more precise instructions are possible. For this purpose, it is particularly advantageous if the image processing program is based on an AI system. In this way, a self-learning optimization of the predefined rating scale or the instructions for setting the at least one parameter can be achieved.

Through this setting of parameters of the crosslinking process, a control loop is installed in which the crosslinking results of the coating obtained using the device according to the invention can be used to set the parameters of the crosslinking process. Such process control is very advantageous because it enables ongoing optimization of the networking process.

This is an advantage even for networking processes that can be carried out relatively safely and are therefore relatively less prone to errors, such as KTL painting. Even with such secure networking processes, the process in industry is usually carried out with a safety margin, e.g. with a duration of 5 minutes longer than actually necessary in order to avoid waste as much as possible. The device according to the invention enables better process control. As a result, the safety margin can be reduced, i.e. the networking parameters such as the duration can be tightened. This means energy can be saved and the coating process is more environmentally friendly.

In a preferred embodiment of the device according to the invention, the UV light source is attached to a holding device and/or the digital camera system is attached to a holding device. The respective holding device can be firmly fixed. Alternatively and preferably, the respective mounting device can enable positioning of the UV light source and/or the digital camera system. The respective holding device can comprise 1 or more degrees of freedom of movement, for example at least 2 or at least 4 lines of freedom. It is preferred that the respective holding device comprises up to 6 degrees of freedom. The holding device can be, for example, a robot arm.

In a preferred embodiment of the device according to the invention, the control unit is configured to control the positioning of the UV light source and/or the digital camera system in relation to the component(s) for lighting and/or recording the image.

The above-mentioned configuration of the control unit is preferably carried out on the basis of image data that is obtained from the evaluation of calibration images using an image processing program, the calibration images being generated using a digital camera system by illuminating and recording coated components with the UV light source. The positioning of the component in relation to the digital camera system and/or the UV light source can be varied. The image processing program used can be the image processing program for evaluating the image data of the captured image or images based on a predefined evaluation scale for the degree of crosslinking of the coating.

The device according to the invention is configured in particular for quality control and/or process control. It is preferred that the device is configured for online control of the degree of crosslinking of the coating in real time or for online process monitoring, control and adjustment of the production line (closed loop).

In a preferred embodiment of the device according to the invention, the UV light source and the digital camera system are arranged in a chamber through which the coated components are passed for image recording. The chamber is preferably arranged directly at the exit of the device for carrying out the crosslinking process, for example a crosslinking oven. The chamber can, for example, be arranged offline or inline for the device for carrying out the networking process. In this way, the degree of crosslinking achieved can be determined very quickly and, accordingly, any necessary changed settings of the crosslinking process parameters can be made quickly. The device for carrying out the crosslinking process is also referred to here as a hardening unit or hardening unit for crosslinking the coating.

The device is thus configured in a preferred embodiment to test the degree of crosslinking at the end of the process, preferably immediately at the end of the process for crosslinking the coating.

By being arranged in a chamber, the operating personnel must be protected, e.g. from UV light. Furthermore, the cleanliness of the components' surroundings can be better controlled. In addition, the arrangement in a chamber makes it easier to set defined lighting conditions for taking the images. For example, it is advisable to take the images of the coated components in a darkened or semi-dark room. This simplifies defined lighting and illumination of the component.

The device according to the invention preferably further comprises a conveyor unit and/or holder for the coated components. This enables the components to be transported in the desired direction. It can be used, for example, to bring a component to be tested into the appropriate position relative to the UV light source and digital camera system and to transport the component further after recording.

The components to be coated can be made of any common material, such as metal or plastic. Components made of metal or metallized plastic are preferred, with metal components being particularly preferred.

The components to be coated can have any geometry, e.g. planar or complex. The components preferably have a complex geometry. In a preferred embodiment, the component to be coated is a vehicle component and in particular a brake component. Suitable components are, for example, a brake caliper housing or a brake holder, especially for motor vehicle disc brakes. However, it should be noted that the device according to the invention is independent of the shape and application of the components and can therefore be applied to all coated components, in particular KTL coated components.

• 1 schematisch einen halbautomatischen Arbeitsplatz für produktionsbegleitende Prüfungen in einer Produktionslinie mit der erfindungsgemäßen Vorrichtung
• 2 schematisch eine vollautomatische Qualitätskontrolle mit Vereinzelung der Bauteile in einer Produktionslinie mit der erfindungsgemäßen Vorrichtung
• 3 schematisch eine vollautomatische Qualitätskontrolle ohne Vereinzelung der Bauteile in einer Produktionslinie mit der erfindungsgemäßen Vorrichtung
• 4 schematisch ein vollautomatisches Prüfsystem zur Steuerung des Aushärteprozesses in einer Produktionslinie mit der erfindungsgemäßen Vorrichtung

The invention is further explained below with reference to schematic drawings, which are not intended to limit the scope of the invention. In the drawings shows:

• 1 schematically a semi-automatic workstation for production-related tests in a production line with the device according to the invention
• 2 schematically a fully automatic quality control with separation of the components in a production line with the device according to the invention
• 3 schematically a fully automatic quality control without separating the components in a production line with the device according to the invention
• 4 Schematic of a fully automatic testing system for controlling the curing process in a production line with the device according to the invention

In 1 A semi-automatic workstation for production-related tests in a production line with the device according to the invention is shown schematically. This is an offline testing station.

A component is coated in a coating unit 1 for coating a component. The coating is preferably a KTL coating. The coated component 3 is then hardened in a crosslinking process, in particular by heating. The curing unit for crosslinking the coating 2 can be, for example, an oven (not shown) to obtain a cured coating. The components with the hardened coating are then fed to the device according to the invention for testing the degree of crosslinking of the hardened coating, preferably by means of a conveyor unit 4, for example a conveyor belt, or a component holder.

The device has a digital camera system 5, a UV light source 6, an output unit 8 and a computer unit 9 in which an image processing program is integrated. The digital camera system 5 is preferably a 2D camera. The UV light source 6 is usually a UV lamp which, for example, emits UV light with a wavelength in the range of 315 - 380 nm.

The digital camera system 5 and the UV light source 6 are preferably installed in a chamber (not shown) in which the testing of the coatings takes place. The digital camera system may also be located on the chamber so that it can capture images within the chamber. The chamber should not be very bright for the test. It is preferably darkened. The chamber is preferably provided with a safety device (anti-glare) to protect operating personnel 7 from UV light.

The UV light source 6 and the digital camera system 5 should be adjustable in as many as four degrees of freedom. For this purpose, the UV light source 6 and the digital camera system 5 are each attached to a holding device, for example a robot arm (not shown). The UV light source 6 and the digital camera system 5 are positioned in a suitable manner in relation to the component(s) for illuminating and recording the image. The positioning shown in the figure is purely schematic.

In the chamber, all or selected components with a hardened coating can be subjected to testing one after the other. For this purpose, the respective component with the hardened coating is illuminated with the UV light source 6 and at least one image of the illuminated coating is recorded with the digital camera system 5. The image data obtained is sent to the image processing program in the computer unit 9 to evaluate the image data with regard to the degree of crosslinking of the coating on the basis of the predefined evaluation scale. The evaluation includes at least a classification into appropriate networking (OK = OK) and inappropriate networking (NOK = not OK). The evaluation is output on the output unit 8. For example, it is stated that the coating is not OK. and the component must be discarded or subjected to subsequent networking.

The operating personnel 7 can then carry out the instructions received at the output unit 8. In this way, a non-destructive and quick measurement error check and validation of the test can be carried out.

2 shows schematically a fully automatic quality control with separation of the components in a production line with the device according to the invention. For 2 Apart from the differences below, the same information applies as for 1 , so that reference is made in this regard.

In addition to the image processing program, the computer unit 10 also has a control unit. The image data, which are obtained by recording at least one image of the component with the hardened coating illuminated with the UV light source 6 by the digital camera system 5, are made available to the image processing program with preset target values according to the predefined evaluation scale. If the evaluation shows that the networking is not appropriate, i.e. networking not OK, this information is sent to the control unit, which, by activating appropriate actuators, e.g. robot arms or other conveying devices, causes the components that have an improper coating to be automatically removed from the production line be expelled. All components of the production line can be tested, allowing complete, fully automatic monitoring of the degree of hardening of the coating on the components.

3 shows schematically a fully automatic quality control without separating the components in a production line with the device according to the invention. For 3 apply the same apart from the following differences Information as for 2 , so that reference is made in this regard.

In contrast to 2 an image of a plurality of coated components 11 is recorded with the digital camera system 5. The plurality of components 11 can be attached to a frame, for example. Of the majority of components is in the 3 only the front shown. The image processing program in the computer unit 10 is configured so that different component geometries can be recorded and evaluated at the same time. The evaluation is sent to the control unit in the computer unit 10. As a result, frames with a plurality of components 11 with insufficiently hardened components (not ok) can be removed from the production line using the control unit and, if necessary, post-hardened. After post-crosslinking, the components 11 can be reintroduced into the production line and subjected to another test for the degree of crosslinking using the device according to the invention.

4 shows schematically a fully automatic testing system for controlling the curing process in a production line with the device according to the invention. For 4 Apart from the differences below, the same information applies as for 3 , so that reference is made in this regard.

On the production line according to 4 The testing point or chamber for testing the degree of crosslinking is located directly next to the curing unit 2 (oven). The UV light source 6 is configured to be thermally stable in order to be protected from the heat from the curing unit. With the UV light source 6, the majority of coated components 11, which are located on a frame, for example, can be completely illuminated. The digital camera system 5 is also designed to be thermally stable or is arranged outside the chamber. With the digital camera system 5, an image of the entire illuminated plurality of coated components 11 can be recorded.

Connected to the digital camera system 5 is the image processing program in the computer unit 10, which is designed so that different component geometries can be recorded and evaluated at the same time. The image data obtained from the digital camera system 5 is used to evaluate the current degree of crosslinking on the coatings. The evaluation from the image processing program is sent to the control unit in the computer unit 10. This allows as in 3 Racks with a plurality of components 11 with insufficiently hardened components (not ok) are removed from the production line using the control unit and, if necessary, post-hardened and then reintroduced into the production line after post-crosslinking.

In addition, the evaluation of the image data in the image processing program in the computer unit 10 includes information for setting at least one parameter for the crosslinking process for curing the coating, which is sent to the control unit, which thereby optionally causes a change at least one parameter for the crosslinking process, e.g Changing the temperature in the oven or the length of time the components stay in the oven of the curing unit. The residence time can be controlled, for example, by modifying the transport speed of the components through the oven. The oven temperature and/or the transport process in the oven can thus be controlled in such a way that ideal networking is achieved. This can reduce both energy consumption and the reject rate.

List of reference symbols:

1

Coating unit for coating a component

2

Curing unit for crosslinking the coating/oven

3

coated component

4

conveyor unit

5

Digital camera system

6

UV light source

7

Operating staff

8th

Output unit

9

Computer unit with image processing program

10

Computer unit with image processing program and control unit

11

Majority of coated components

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102020203343 A1 [0008]

Claims (15)

Device for testing the degree of crosslinking of a coating hardened by a crosslinking process on components in a production line, wherein a fluorescence wavelength of the coating emitted under UV light depends on the degree of crosslinking, the device comprising a) a UV light source for illuminating the coating on at least one of the components, b) a digital camera system for recording at least one image of the coating illuminated with the UV light source, c) an image processing program for evaluating the image data of the recorded image or images based on a predefined evaluation scale for the degree of crosslinking of the coating, which has at least one classification into appropriate crosslinking and inappropriate crosslinking, on the basis of which the evaluation is carried out, d) an output unit and/or a control unit for controlling at least one of the following measures based on the evaluation received from the image processing program: i) Rejecting components from the production line which, according to the evaluation, do not have adequate cross-linking of the coating, whereby the rejected components can be discarded or subjected to subsequent cross-linking for the coating, ii) Setting at least one parameter for the crosslinking process to cure the coating. Device according to Claim 1 , wherein the UV light source is attached to a mounting device and / or the digital camera system is attached to a mounting device, wherein the respective mounting device is either firmly fixed or enables positioning of the UV light source and / or the digital camera system, the respective mounting device up to Includes 6 degrees of freedom. Apparatus according to any preceding claim, wherein the control unit is configured to control the positioning of the UV light source and/or the digital camera system in relation to the component(s) for illuminating and/or capturing the image. Device according to Claim 3 , whereby the configuration is carried out on the basis of image data which are obtained from the evaluation of calibration images using an image processing program, the calibration images being generated using the digital camera system by illuminating and recording coated components with the UV light source, the positioning of the component being in Relation to the digital camera system and/or to the UV light source can be varied. Device according to one of the preceding claims, wherein the evaluation scale has a classification of the degree of crosslinking in several, for example at least three or three, levels and / or the evaluation scale has a classification of the degree of crosslinking depending on at least two partial areas of the coating, the evaluation of the image data of the or of the captured images contains an instruction to maintain or change at least one parameter that is relevant to the networking process, determined by analysis using the rating scale. Device according to one of the preceding claims, which is configured for quality control and/or process control, in particular for - Online control of the degree of crosslinking of the coating in real time or - Online process monitoring, control and adjustment of the production line (closed loop). Device according to one of the preceding claims, wherein the UV light source and the digital camera system are arranged in a chamber through which the coated components are passed for image recording, which is arranged either offline or inline, directly at the exit of the device for carrying out the networking process. Device according to one of the preceding claims, further comprising a conveyor unit and/or holder for the coated components. Device according to one of the preceding claims, which is configured to record at least one image of a single component or a partial area of the component or at least one image of a plurality of components for testing the degree of crosslinking of the coating. Apparatus according to any preceding claim, configured to perform the degree of crosslinking test at the end of the coating crosslinking process. Device according to one of the preceding claims, wherein the coating is a KTL coating and/or wherein the change in the fluorescence wavelength emitted under UV light appears in the visible range. Device according to one of the preceding claims, wherein the component preferably has one Vehicle component or a brake component, such as a brake caliper housing or a brake holder, in particular for motor vehicle disc brakes. Device according to any preceding claim, wherein the UV light source is at least one UV lamp with a wavelength in the range of 315 nm to 380 nm. Device according to one of the preceding claims, wherein the digital camera system is a camera for spatial image recognition. Device according to one of the preceding claims, wherein the image processing program for evaluating the image data is based on an AI system.

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