参考答案

总加工余量、各层背吃刀量及主要加工尺寸如下表所示。
总加工余量 R=30 背吃刀量a_p 精加工(第4层) 粗加工(第3层) 粗加工(第2层) 粗加工(第1层) 1 9 9 11 主要加工尺寸R 30 29(30-1) 20(29-9) 11(20-9)
编程如下：
N10 G50 X104.0 Z30.0
N20 G00 X58.0 Z2.0
N30 G01 X58.0 Z0 F0.3
N40 G02 X80.0 Z-11.0 R11.0 F0.3
N50 G00 X90.0 Z-11.0
N60 G00 X104.0 Z30.0 (粗加工R11)
N70 G00 X40.0 Z2.0
N80 G01 X40.0 Z0 F0.3
N90 G02 X80.0 Z-20.0 R20.0 F0.3
N100 G00 X90.0 Z-20.0
N110 G00 X104.0 Z30.0 (粗加工R20)
N120 G00 X22.0 Z2.0
N130 G01 X22.0 Z0 F0.3
N140 G02 X80.0 Z-29.0 R29.0 F0.3
N150 G00 X90.0 Z-29.0
N160 G00 X104.0 Z30.0 (粗加工R29)
N170 G00 X20.0 Z2.0
N180 G01 X20.0 Z0 F0.15
N190 G02 X80.0 Z-30.0 R30.0 F0.15
N200 G00 X90.0 Z-30.0
N210 G00 X104.0 Z30.0 (精加工R30)