Evaluation process
In order to find various possible defects on different surface shapes, we have developed several evaluation procedures. Whether small, short-wave errors or large, long-wave discontinuities must be recognized and objectively evaluated - we have the ideal tool for you. The evaluation procedures Digital Master, Digital Shape and Digital Stone provide a DefectMap that shows all deviations with their lateral expansion including the height/depth. Red signifies an upward deviation, blue a downward deviation. The identified deviations are automatically evaluated using customizable limit values. In addition, a report containing the inspection results can be generated.
In the first step, the parts are chosen, which are accepted as OK by the customer. The surfaces of these components are captured with the surfaceCONTROL 3D sensor. The parameters of acceptable surface forms are calculated via the generated 3D-data and archived in an associative memory. Behind this is a neuronal network, which is trained with the data. In the inspection process the surface data of the object to be inspected is first captured with the sensor. Afterwards the software reconstructs the object based on the trained data and calculates an individual master. Then it is compared against this master. When there are no differences between the calculated master and the part that is controlled, the part is flawless. Deviations are shown in a DefectMap. This process is ideally suited to series control.
The 3D data of the surface is described by a set of mathematical functions using two dimensional polynomial approximation. Depending on their degree, the polynomials have the ability to adapt the shape of the surface like an envelope. The 3D data is compared against the calculated envelope and possible deviations in the surface are identified as defects. The digital shape evaluation is suited for fast analysis of flat and slightly curved surfaces.
The digital stone is directly used on the previously captured 3D data. During this process the software determines the two highest points (point of support) along a line segment. Afterwards the gaps between the line segment and the 3D-data are calculated. It is mainly used in the analysis of defects in the toolmaking process as well as in pre-production series.
It can be very difficult to detect very small local deviations on tested components. It is common practice, for example, to paint vehicle body parts in glossy black and inspect under special lighting, such as a light pipe, in order to get a visual impression of a defect's geometric form. This process cannot be used for all surfaces, it requires additional time and material, and the components cannot be used afterwards. This is why surfaceCONTROL offers the possibility to impose defined characteristics (color, glossy finish) onto the captured 3D surfaces and inspect them on the monitor either under diffuse lighting or with a light bar. So without any additional material even the smallest defects become visible and can be assessed visually.
