【作者】 刘婷；

【导师】 徐宗伟；

【作者基本信息】 天津大学 ， 仪器科学与技术， 2014， 硕士

【摘要】 近年来,高精度、结构复杂、材料多样性的微小型设备在医疗仪器、微电子封装、航天航空等不同的领域得到越来越广泛的应用,与此同时,人们对微加工制造技术提出了更高要求。微铣削技术作为微加工技术中的关键技术之一,因其加工的高效性、灵活性、加工材料和结构的多样性备受人们青睐。微铣削技术的研究主要包括切削力特性、切削力建模、最小切削厚度、加工质量、尺寸效应、切屑形成等方面。微铣削切削力的大小会影响到刀具的变形和磨损、零件的尺寸精度和表面质量,分析或预测切削力对于监控刀具状态、选择合理的加工参数有重要意义。微铣刀的切削刃刃口半径对加工过程有重要影响,对此展开研究有助于理解微加工机理。首先,本文通过直径150?m微铣刀铣削H62黄铜实验,研究了主轴转速、轴向切削深度和每齿进给量这三个关键切削用量变化时,微铣削切削力的变化规律。实验得出,主轴转速对进给方向的分力有很大影响;当轴向切深和每齿进给量增大时,切削力增大。其次,在微铣削H62黄铜实验中发现,当每齿进给量减小时,切削比能增大;用直径600?m微铣刀加工H68黄铜和硬质Al合金,其切削比能表现出类似的尺寸效应现象;根据实验结果,分析得出刃口半径是造成尺寸效应的关键影响因素,论文建立了切削比能经验公式。最后,以每齿进给量为变量,研究了铣削H62黄铜实验中微沟槽毛刺和表面粗糙度的变化规律,研究发现当每齿进给量与刃口半径的比值fz/Re减小时,毛刺宽度和表面粗糙度均先减小后增大,当fz/Re等于0.5时,毛刺最小,fz/Re等于1时,表面粗糙度最优。对比分析切削比能和毛刺宽度、表面粗糙度随fz/Re的变化规律曲线发现小进给条件下,切削比能较大时,毛刺宽度、表面粗糙度较大,因而可以通过监控切削力并计算切削比能,根据切削比能的大小来调整切削用量,实现优化加工质量的目的。更多还原

【Abstract】 In the recent years, micro equipment with high-precision, complex structures are widely applied in different areas such as medical equipment, aerospace and so on. In the same time, people make higher demand for micro machining technology.People pay much attention on micro milling because of it is efficient, flexible and can create complex three-dimensional parts of different materials. Researchers pay attention on cutting force, size effect, surface quality or other fields in order to raise efficiency, improve quality. The cutting force in micro milling have effect the function of cutter, and the shape of a part and he cutting edge radius effects machining process. To do research on these fields can help guiding machining.Firstly, cutting force was studied by milling experiments. The effects of spindle speeds, feed per tooth and axial cutting depth on cutting forces were investigated, by using a carbide micro milling cutter with 150μm in diameter to cut brass H62. Results showed that spindle speeds have significant effect on feeding cutting force; when feed per tooth and axial cutting depth increased, cutting force increased too.In addition, the specific cutting energy in micro milling was observed by studying the effect of the ratio of feed per tooth to the cutting edge radius. Results showed that while feed per tooth was decreasing, the specific cutting energy began to increase. This result could be shown when using a carbide micro milling cutter with 600μm in diameter to cut brass H68 and Al.Thirdly, the effects of the cutting edge radius on the burr size and surface roughness were explored. Results showed that while feed per tooth was decreasing, the burr size and surface roughness began to decrease at first and then began to increase, and the best machining parameters were put forward. The research showed that when feed per tooth was little, the burr size and surface roughness were big. The result could help improve quality by measuring cutting force and got the specific cutting energy to adjust cutting parameter.更多还原