Study On The Key Technology Of Cyclic Multi-point Incremental Forming Process For Ship Building

To explore the ocean resource, China aims to improve its capability for construction of large ships. The thick plate forming process of complex curved surface has already become one of technical bottlenecks in the field of shipbuilding. Over the years, the shipyard has been using manual methods for thick plate forming, namely combination of line heating and mechanical press. Workers have to suffer from the bad working condition, highly working load as well as pollutions and the conventional forming process has low efficiency. In addition, the quality of product is largely depended on workers' experience and it is not easy to be controlled. There are mainly two types of flexible sheet metal forming methods: single-point incremental forming process and multi-point forming process. However, the former process is not available for forming thick plate with low surface quality and the second process requires a large mechanical press that is expensive. Extracting the advantages of the two flexible forming process, a new forming process, also called cyclic multi-point incremental forming(CMIF), is proposed to meet the small batch production of large ship plate forming with low cost. The main contributions are listed as following:(1) The analytical models are proposed based on the working principle for predicting the forming mechanics and springback as well as the forming limit of cyclic multi-point incremental forming process.(2) Two processing schemes developed for the proposed CIFP process are single side cyclic incremental forming and double-side cyclic incremental forming, and finite element analysis are conducted to evaluate the feasibility of the process for thick plate forming.(3) A series of experiments are carried out on the manual test bench for cyclic multi-point incremental forming. The experimental results are compared to FEM simulation and difference is well studied and discussed.(4) To improve the precision and efficiency, the automatic experimental setup is designed with two parallel mechanism and its dynamics model are build and simulated to optimize the proposed design.Outcomes of this research provides a potential solution for forming thick plate with complex surface for ship building in high efficiency and low cost. Also, the process can be applied to the other related industries.