文档介绍:Last updated at 10:00 am on 25th December 2020
机械设计与制造毕业论文
毕业设计
机械加工表面质量的影响因素
学 生 姓 名: 王仲果 r, not only directly affect the performance of parts, but also may cause stress concentration, stress corrosion, will further accelerate the parts failure, all this has much to do with the quality of the machined surface. Thus the surface quality problems become more and more important. A machine in normal usage process, the working performance of the part gradually deteriorated, so that cannot continue to use, and sometimes even the sudden damage. The reason is because the design is not in a few weeks and the strength is not enough, or accident caused by overload, mostly due to wear, corrosion or damage the external medium fatigue. Wear, corrosion and fatigue damage occurs in parts of the surface, or from parts of the surface. Therefore, the machined surface quality will directly affect the performance of parts, especially its reliability and lifetime. Based on the analysis of the machining surface quality, pointed out the factors influencing the surface quality of machining, and proposes to improve the machined surface quality measures, there are some guidance for engineering practice. Moreover, the correct understanding of the content of the surface quality of parts, various technological factors affecting surface quality analysis of machining process, by changing these factors so as to improve the quality of the workpiece surface, improve the performance of products and plays an important role in the future development of machinery industry.
Keyword surface quality, surface roughness, mechanical properties, cutting parameters
第一章 基本概念
机械加工
机械加工:广意的机械加工就是凡能用机械手段制造产品的过程;狭意的是用车床、铣床、钻床、磨床、冲压机、压铸机等专用机械设备制作零件的过程。
切削加工
刀具几何形状的复映刀具相对于工件作进给运动时,在加工表面留下了切削层残留面积,其形状是刀具几何形状的复映。减小进给量、主偏角、副偏角以及增大刀尖圆弧半径,均可减小残留面积的高度。此外,适当增大刀具的前角以减小切削时的塑性变形程度,合理选择润滑液和提高刀具刃磨质量以减小切削时的塑性变形和抑制刀瘤、鳞刺的生成,也是减小表面粗糙度值的有效措施。
工件材料的性质。加工塑性材料时,由刀具对金属的挤压产生了塑性变形,加之刀具迫使切屑与工件分离的撕裂作用,使表面粗