Traditional measurement methods include manual measurement and large-scale three-dimensional scribing instrument, which have low measurement accuracy, high error rate, low efficiency and equipment can not be moved. At present, there are more and more types of large steel castings and their shapes are more and more complex, such as various complex curved surfaces on the outer wall of gas turbine and nuclear power steam turbine castings, hydraulic profile of turbine blades, some inner walls, cavities, holes and other parts of large mining machinery parts, which can not be measured by conventional manual and three-dimensional scriber. The size detection in the molding process, such as the sand mold and sand core in the molding pit, cannot be measured because the measuring instrument cannot move to the molding pit. Due to the limitation of the structure of the three-dimensional scriber, the inner complex shape of some core boxes can not be measured.
Through the application of the new size measurement system, the size inspection method and process of large steel castings are changed, the size measurement range of large steel castings is expanded, the control ability of the whole process size measurement is improved, and the service for the whole process manufacturing process and design innovation of large steel castings is provided.
(1) The whole process dimension measurement control of large-scale steel castings is realized, and the dimension measurement inspection is extended to the pre production sequence of steel castings, which improves the qualification rate of dimensional tolerance of large-scale steel castings.
(2) After the application of photogrammetric system, the semi-finished product areas (semi-finished product in molding pit, large sand mold and casting mold) which could not be measured before can be measured.
(3) The measurement blind area of large steel casting inner cavity and hole is realized.
(4) The precision and efficiency of large-scale steel casting dimension measurement are improved (the instrument has high precision, the software fitting calculation is realized, and the lifting and transferring time of large-scale steel casting is saved).
(5) The measurement cost and manufacturing cost in the production process of large steel castings are reduced (the cost of lifting and transferring large steel castings is saved),