Undifferentiated pancreatic carcinoma with osteoclast-like giant cells: A rare entity with potential misdiagnosis of a gastrointestinal stromal tumor on preoperative evaluation

摘要

The surface topography of carbon fiber reinforced plastic composites after machining processes like milling or grinding has a complex character due to the inhomogeneous material structure. The usual procedure to evaluate the surface topography is given with the usage of parameters that describe one or more specific features of the surface. In mechanical engineering, for example, the roughness parameters Ra, Rz, Rmax and Rt have been established with tactile-based roughness measurement devices. However, the applicability of several parameters is not always suitable for composites. In this work the influence of the measurement positions, the distribution of the measured values and the behavior of these values in respect to the machined surface structure are analyzed by means of optical as well as tactile surface measurements. This work results in recommendations for the measurability of machined surfaces of carbon fiber reinforced plastics by using tactile profile methods and an assessment of the derived roughness parameters.