Abstract: In view of the measuring problem for dimension, form and position error of shell body in high temperature, a new principle is proposed and a special measuring system is successfully developed. The working principle, basic structure, software and hardware of the system, and the methods of data processing and compensation of thermal deformation are introduced. A measuring example is given. The practical use indicates this system can realize automatic measurement of shell body accurately and rapidly, thus solving a difficult problem of hot extrusion forming line of shell body .

Key words: Geometric accuracy, Online measuring, Shell body, Thermal deformation compensation