涡旋曲面铣削加工工艺改进

涡旋线是一种曲率在时刻变化的复杂曲线,涡旋面铣削加工中,动态前后角、切削层厚度(切深)以及切削力都随之变化,如果切削用量设计不当,将使动态切削状态恶化,严重降低刀具寿命,影响加工效率,这些影响切削性能的因素都与进给量直接有关。当曲率增大,切深加大,动态后角变小,以及切削力增加,这种现象明显地表现在涡旋曲线接近中心的部位,往往导致刀具急剧磨损以致断裂,严重影响生产率。因此涡旋曲面铣削加工进给率计算必须考虑其曲率的变化,但通常是根据经验按曲率的变化分段安排进给率,不是以精确计算为依据。为了改进涡旋曲面铣削加工工艺,本文工作结合涡旋压缩机主体涡旋盘常用的涡旋线建立数学模型,计算单位时间进给的切削层厚度,提出进给率优化方法,并利用Weilenmann方法计算相应的切削力,参照工艺性和经济性的要求、改善现行的涡旋加工工艺。

Improvement of machining technology for scroll surface milling

The spiral is a complex curve with variation curvature.Machining of the scroll surface is a process of variation dynamic cutting angle,cutting thickness(depth),and cutting force.If the cutting parameters are not correctly designed,the dynamic cutting behavior may be deteriorated and results to tool-life worsening and cutting efficiency reducing.Feed rate is of primary importance to the cutting performance.For a definite feed rate,the cutting thickness increases,dynamic relief angle deceases,and cutting force aggravates when the curvature becomes larger.This phenomenon exhibits severely in the center neighborhood of the surface.It always causes serious wear of cutting tool and significant loss of productivity.Thus,the feed rate scheduling is essential to technology design in scroll surface milling.But,it is usually divided empirically by segments,not based on accurate computation.This thesis work is aimed at improving the milling technology.The feed rate scheduling for the main component of a scroll compressor is illustrated.Based on the surface modeling,cutting thickness for unit feed rate is evaluated.An optimized scheduling for the scroll surface milling is proposed.Cutting force calculated according to Weilenmann method is also considered to improve the technology.