Principle and characteristics of NC machining of Moldless mold for large steel castings

Rapid Moldless mold processing and production driven by digitization is not only a common technology in modern industrial production, but also a common process for the manufacture and processing of equipment and materials of large steel castings. The working principle is as follows: the specific parameters of the mold, such as length, width, height, internal and external diameter, are obtained through actual measurement, and then the specific parameters are transformed into electronic data by computer equipment – the virtual model of large-scale casting mold is constructed in computer equipment through electronic computer equipment and specific large-scale casting mold software, Then convert it into CAD data and output the three-dimensional CAD model – upload the CAD model data to the production and processing lathe, and the computer makes the optimal pouring path planning according to the model parameters and the specific working parameters of the lathe – operate and simulate the rationality and scientificity of the optimal pouring path planning obtained in the previous link through specific software, To obtain the simulation model (data) of large-scale casting mold manufacturing is simply to simulate the real pouring environment in the background of computer software, evaluate the rationality of design, planning and large-scale casting mold itself, and confirm whether it can be put into the lathe for processing – if the simulation in the previous link is passed and the simulation model is output, the data will be transmitted to the lathe control equipment according to the simulation results, Officially enter the link of large-scale casting mold manufacturing and processing – CNC lathe completes the manufacturing and processing of large-scale casting mold under the control of computer, and obtains the final mold.

The numerical control machining of large Moldless casting mold is to process the sand mold directly under the drive of 3D CAD of the mold to obtain the large casting mold, and then pour it to obtain the finished large casting. Therefore, the mold NC machining technology of modeless large castings has a high dependence on the reliability of tool equipment, the accuracy of calculation value and the stability of electromechanical equipment. Slight deviation can lead to the defects of the final product. The equipment is a large-scale casting manufacturing and processing technology integrating CAD technology, casting technology and NC lathe processing technology. It does not need patterns for modeling, but uses NC technology to replace traditional molds and patterns, and uses the advantages of digitization, precision, flexibility and greening of NC technology to replace traditional large-scale casting manufacturing. At present, the reliability and safety of this technology have been confirmed in the research in the field of steel equipment and material manufacturing in China. It is an ideal large-scale casting manufacturing process at this stage.

The technology mainly has the following characteristics: ① the production process is relatively simplified, which omits the link of manufacturing mold in the manufacturing process of traditional large-scale metal castings, and greatly shortens the processing and manufacturing cycle. Therefore, the overall cycle from design to obtaining finished products is shorter and the production efficiency is higher. ② Combined with computer technology and numerical control technology, the manufacturing accuracy of large metal castings is greatly improved, there is no need to reserve draft angle in the process of production, and there is less manual intervention in the production process. It can effectively avoid the manufacturing error of large castings caused by human factors. ③ Under the NC technology, large-scale casting mold manufacturing does not need to make physical objects, but can simulate the mold and large-scale casting pouring through calculation, and this process can be realized repeatedly in the computer. It can be used in the design, development and processing of large-scale metal castings, which can effectively shorten the product development cycle of large-scale metal castings and provide new technical support for the upgrading of industrial products in China.