Development of a miniaturized optical roughness sensor for the classification of machined surfaces
|German title:||Entwicklung eines miniaturisierten optischen Rauheitssensors zur Klassifizierung bearbeiteter Oberflächen|
|Duration:||1st June 2012 - 31st May 2014|
|Description:||The project dealt with the development of an optical roughness sensor for the classification of machined metallic surfaces for use on machine tools. The measuring system was to be integrated and functionalized to such an extent that it can be used for in-line application on machine tools and processing machines. The application area of the system is in the production and manufacturing process for online analysis of the chip removal process, process control and quality assurance. The overall system includes an optical detector, a directional laser light source and electrical signal processing. The area of application also places high mechanical demands on the system, which requires robust and energy-autonomous integration.
Based on the objective, a transmitter-receiver unit was developed, which projects a laser beam onto the sample to be measured and reads it with an adapted detector. The emitter component consists of a laser diode (VCSEL) and optics mechanically aligned to the detector. The laser light is focused on the workpiece surface under test and has a spot diameter of 15µm. The control of the components, the electrical signal processing and the storage of the measured values is done with microcontroller controlled readout electronics and serial data transmission. A software controls the measurement process and the electronics and receives and visualizes the acquired measurement data. The created components were integrated into a modified drill head, which protects the transmitter-receiver assembly, the evaluation electronics and the components for data transmission and the self-sufficient power supply from mechanical stress. Reference samples were measured on a demonstrator for functional verification.
The sampling rate is approx. 10kSa/s, which corresponds to a lateral resolution of less than 1µm at a measurement feed rate of 1mm/s. The resolution of the roughness is 1µm to 20µm, depending on the surface profile. The optical measurement of roughness was compared to the tactile measurement and good agreement was found even over multiple size scales on the same sample. A conversion of the measured values to a standardized norm has not yet been carried out.
The good results create very good chances for economic exploitation. The integration of the roughness sensor in machine tools is relatively simple due to the self-sufficient supply and serial data communication and thus offers good market access. Adaptations to software and measured value analysis and possible mechanical modifications can be carried out promptly with the components created. In addition, the pure beam receiver assembly offers the potential to be used in other market areas (e.g. triangulation measurements).
|Markets:||Automation, Metrology, Mechanical Engineering|
|Contact:||Contact us about this project via our business unit MOEMS|
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