Flash butt welding is widely used as an effective welding method in the fields of a ship and marine engineering, transportation, oil drilling, and the metallurgical industry. The current flash butt welding machine basically has a large energy consumption, welding process instability, etc. To solve the above problems, this paper proposes a flash butt welding method and designs a DC flash butt welding equipment. Then, this paper uses Solidworks to establish a three-dimensional model of the above-mentioned welding machine. And through the finite element static analysis of the welding machine structure to assist in the design and optimization.

The virtual machining process system is built based on VERICUT platform to simulate the whole procedure of machining marine diesel engine key parts. It changes the traditional method of test-cutting, shortens development time and ensures the safety of the actual machining process system. Examples of machining marine diesel engine frame and cylinder cover are done to verify the effectiveness of this system. It is demonstrated that it has a wide application future and spreading value in the production of marine diesel engine key parts and the whole manufacturing industry.

In order to solve the problems that traditional kinematics model built by the method of D-H parameters can only reflect relative movements between adjacent components and can't express directly the spatial poses of every component relative to static platform, Lie-algebras is used this paper to establish the product of exponential formula of forward direct kinematics of every branch chains. The elimination method and Paden - kahan sub-problems are used to calculate joint variables. Then the quick and intuitive inverse algorithm of cross rods parallel machine tools is acquired. The algorithm provides reliable proofs for the analysis of error compensation, kinematics interference and singularity. Finally we prove our theory with an example of an actual parallel machine tool.