Research On The Reduction Effect Of Turbine Mortise Broach With Micro-texture Friction Surface

Environmental protection and high efficiency gradually become the new trends as the continuous development of modern metal machining technology. In the process of machining, the resistance between cutter and workpiece is one of the major reasons of tool wear and energy waste. Recently, the anti-friction effect of surfaces with reasonable micro-texture was found in the field of tribology, and micro-texture was made on surface to reduce the friction. Now, related researches had proved that tools with micro-texture had the better cutting performance and lower tool wear. Meanwhile, non-smooth surfaces with unique features of creatures provided a rich configuration resource for the research of micro-texture tool.Broach is a type of complex cutting tools, especially for the broach that used for fir-type groove’s manufacture of heavy-duty gas turbine, whose broaching force is large, broaching temperature is very high and tool wear is serious in the broaching. In addition, even no enterprises in China can produce the large-size broach because of its complex construction. Therefore, the broach is mainly relied on import, and the cost is very high. In this paper, friction surface of broach is designed according to the idea of bionic micro-texture to achieve the purpose of reducing cutting force and improving cutting efficiency. The main research works are as follows:(1) The types and sizes of bionic micro-texture and the current research status of tools with bionic micro-texture were analyzed, and the broaching process and research status of broaches that used for fir-type groove’s manufacture of heavy-duty gas turbine were summarized.(2)The cutting processes of carbide tools with micro-texture and with no micro-texture were analyzed by ABAQUS. Then, the stress distribution of tool and the resistance force between tool and workpiece during the cutting process were analyzed. The results showed that the stress distribution of tool with micro-texture was uniform and the resistance force was smaller. The results provide certain of basic for the design of micro-texture on tool surface.(3)The dimension parameter of micro-texture was studied, and micro-textures were processed in the surface of YT5and YT15carbide tool using laser processing technology. Then, cutting experiments were proceeded. Cutting forces were obtained by multipurpose dynamometer and analyzed. The results showed that micro-texture could reduce the cutting forces, temperatures and tools wear obviously. From the above, tools with micro-texture had the effect of anti-friction and reducing tool wear. In which, the micro-texture of perpendicular direction and smaller dimension has better anti-friction effect.(4) Wear experiments of the tool with micro-texture and the tool with on micro-texture were conducted. Cutting forces, cutting temperatures, tool wear and chip conditions were analyzed. The results showed that tools with micro-texture had the smaller cutting forces, the slighter tool wear, the lower cutting temperatures and the better chip shape. Anti-friction mechanisms of micro-texture were summarized according to experiments results, which can provide certain of theory support for all the studies in this paper. The anti-friction mechanisms mainly includes:secondary lubrication, storage chip and reduce the contact area, reduce the contact length between chip and tool and produce the fluid dynamic pressure effect.(5)The structure characteristics of mortise of heavy duty gas turbine were summarized, and the characteristics and application scopes of each broaching method were analyzed. The influence of broach geometry parameters on broaching was summarized. The reasons of heavy wear of broach that used for fir-type groove’s manufacture of heavy-duty gas turbine were analyzed, and the conceive of applying micro-texture to broach was put forward. Finally, the design thought of micro-texture broach was given. Then, the statics analysis of broach was conducted, and the stress distribution of broach was analyzed. The results showed that the stress distribution of broach with micro-texture was uniform and the phenomenon of stress concentration was avoided effectively.