Research On Micro-grinding Process

MEMS can be operated in a small space without disrupting the work environment, so it is applyed in the aerospace technology, precision instruments, bio-medical and other fields, and paid much attention by many countries. Therefore, how to produced the parts with small feature size has become a hot research topic in recent years.Micro-machining technology can adapt to a variety of non-silicon materials, especially to the metals with high aspect ratio or three-dimensional structure, it is suitable for small molds, micro-fluid systems, and the preparation of micro drives.In recent years, micro-milling has developed rapidly, especially in the manufacturing of the micor-tool and micro mold, and it have gradually entered the commercialization stagein the developed countries.Although micro-milling has become commercial, the surface quality is almost not so good in micro-milling. The ratio of shape size and surface roughness can be greater than106in traditional mechanical parts (shape size is greater than lmm, surface roughness is less than10μm), which is sufficient to meet requirements. But in micro mechanical parts, the shape size is less than lmm and the surface roughness is generally sub-micron scale (0.1μm～1μm), the ratio of them is less than103～104. It leads the surface quality is bad in micro machining. Therefore, the use of micro-grinding process to obtain good surface quality is an important area of microscale processing research. In micro-grinding process, micro grinding tools are less than lmm and mostly cylindrical. The process directly remove material of parts to form the desired surface morphology or make surface finishing after other processing to meet process requirements.In this thesis, research on the process mechanism of micro grinding, first, take advantage of the traditional grinding mechanism to research on the micro-grinding mechanism, analyze the shape of the micro-grinding chip and arc length of the contact with the workpiece that are different from the traditional grinding process, then establish the theory model of micro-grinding.Second, make use of the ABAQUS/Explicit analysis module to establish coupled thermo-mechanical model, analyze the temperature field of the micro-grinding and determine the maximum cutting temperature region, summarize cutting temperature and cutting force variation under the different cutting depth and cutting speed. Obtain the value of the minimum chip thickness in the finite element analysis model,and make a contrast with the minimum chip thickness theory.Third,choose the processing parameters of micro-grinding based on the experiment platform to analyze the basic structural dimensions of micro-grinding tools, then analyze the influence on the precision of the micro-grinding when the micro-grinding tool has elastic deformation, summarize the precision of the micro-grinding under the different cutting depth and micro-grinding tools.Finally, get the experimental measurements of the cutting force and its variation range under different cutting depth, cutting speed, and make a contrast with the results of the previous finite element analysis. Based on the experimental results, obtain the relationship between the radial force and the cutting depth and analyze the precision to get the optimization choice of processing parameters and the size of micro-grinding tools.