摘要
两刀位点间连线与原有刀具轨迹所在平面的夹角α(或曲面上刀位数据的Z坐标增量Δz)对基于CAD/CAM的复杂曲面数控三坐标投影加工误差十分敏感.当用弦长代替弧长时,投影加工两刀位点间直线插补轨迹的法向加工误差Δt是以原有刀具轨迹走刀步长或行距加工曲面时两刀位点间直线插补轨迹的法向加工误差Δy的cos2α(0°<α<90°)倍.若α(或Δz)达到一定值,就会因原有走刀步长或行距的过渡拉伸而产生严重的过切(步长拉伸时)或欠切(行距拉伸时)现象,使被加工曲面出现明显的折面或残留面.应引入控制参数α(或Δz),根据曲面加工精度要求设定限值αmax(或Δzmax),当α>αmax(或Δz>Δzmax)时,进行刀位密化处理,以保证曲面加工精度.
Based on the analysis on the errors of projecting machining for complex surface of 3-axis, the machining errors will be greatly affected by the angle(α) formed by the line of two cutter locations as well as the surface on which tool-path exists. The error of projecting machining is considered as Δt and the error of machining on step length of existing tool path is considered as Δy, provided the arc length is substituted by the string. Therefore Δt is cos^2α times of Δy.Over cut or deficient cut happens if the length or the interval is greatly lengthened, when α is up to a certain value. The machining surface becomes discontinuous small surfaces or possesses left-over. α should be selected with a limited value (α\-\{max\}), which is based on the surface accurate. more cutter locations should be inserted.
出处
《成组技术与生产现代化》
2003年第4期48-50,共3页
Group Technology & Production Modernization
关键词
复杂曲面
数控加工
投影加工
误差
complex surface
NC machining
projecting machining
error
