| Rotary ultrasonic machining (RUM) is one of the available methods to machine the engineering ceramics, but it is difficult to manufacture the tool, and the tool ware is serious. These problems badly limit its application, especially when complex shape will be machined.An alternative approach is to use a simple "pencil" tool and contour machine the complex shape. According to the rapid protocol manufacturing (RPM) method, a new CNC machining method called rotary ultrasonic layered milling (RULM) is brought forward. In the method, simple tools are used to layered machine the workpiece like face milling.In this investigation, a five-variable two-level fractional factorial design is used to conduct the experiments. The purpose of these experiments is to reveal the main effects as well as the interaction effects of the process parameters on the process outputs such as Material Removal Rate (MRR), cutting force, material removal mode and surface roughness. In addition, the mechanism model of the material removal rate is analyzed.The conclusions are showed as follows: (1) Ductile removal mode percentage will increase as the rotation speed, indention depth and abrasive level rise. (2)Only depth of cut and federate have effects on material removal rate (MRR). (3) For main effects, tool level has most significant effects on cutting force and material removal mode, tool level and speed level have most significant effects on surface roughness.(4) Higher percentage of ductile mode tends to produce a better surface (low value of surface roughness).In the last of this paper, the tool design and wear are discussed, and the slope angle of the tool is pointed as an important parameter to control the wear rate of the tool.The practice application of the RUM will be benefited from the research of this paper. It not only brings the experiment data for the foundation of the expert system, but also explores the mechanism model of the RUM. |
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