A.G91 G03 X20.0Y0I-20.0J0 F100; B.G90 G03 X20.0Y0I-20.0J0 F100; C.G91 G03 X20.0Y0R-20.0 F100; D.G90 G03 X20.0Y0R-20.0 F100;
A.G41为顺铣,G42为逆铣 B.G41为逆铣,G42为顺铣 C.与G41、G42无关 D.与G41、G42有关,也与G02、G03有关
A.G41、G49 B.G19、G20 C.G0、G03 D.G91、G99