110,1.0,1,0,0.0,5,0,5.0,0.0 7P0000004
100,0.0,0.5,0.5,0.0,0.0,1.0,1.0 9P0000005
3.2 文件转换
IGES文件主要用于AutoCAD与高级语言程序间的连接，其数据结构形式不能满足NC的要求，必须重新加工处理，处理的方法是在IGES文件的参数数据段中提取几何元素（如 直线的起点、终点坐标，圆弧的弧心坐标、半径、起点、终点坐标等），元素排序（按元素的连接顺序排列），在此基础上生 成方便NC加工的APT文件。图形文件的转换流程如图2所示。
图2 图形文件的转换流程图
3.3 NC工艺参数的确定
NC工艺参数是以人机对话方式输入计算机的。在读取TXT文件来生成APT源程序的几 何定义语句、刀具运动语句的同时，对刀法、对刀点、容差、刀具参数、机床指令等一些参 数以人机对话方式输入。最终生成符合APT语言的源程序。
4 应用实例
图3为一典型的直线—圆弧零件，在该零件中，既有直线—直线相连，又有直线—圆弧相连，又有圆弧—直线相连。利用 本系统自动生成的零件APT源程序如下:
PARTNO/TEST PART
MACHIN/2
CLPRNT
INTOL/0.01
OUTTOL/0.01
CUTTER/12
| L1 | =LINE/-269.641022,0.000000,35.000000,0.000000,0.000000,35.000000 |
| L2 | =LINE/0.000000,0.000000,35.000000,-0.000000,100.000000,35.000000 |
| L3 | =LINE/0.000000,100.000000,35.0000,-235.000000,60.000000 ,35.000000 |
| C4 | =CIRCLE/-235.000000,20.000000,35.000000,40.0 00000 |
| SETPT | =POINT/-320.000000,-75.000000,0.000000 |
| PT | =POINT/-320.000000,0.000000,0.000000 |
| FEDRA T/50 | |
| SPINDL/900,CLW | |
| FROM/SETPT | |
| INDIRP/PT | |
| GO/TO,L1 | |
| COOLN T/FLOOD | |
| TLRGT,GORGT/L1,PAST,L2 | |
| GOLEF/L2,PAST,L3 | |
| GOLEF/L3,TANTO,C4 | |
| GOLFT/C4,PAST,L1 | |
| SPINDL/OFF | |
| COOLNT/OFF | |
| FEDRAT/200 | |
| GOTO/-320.000000,-75.000000,0.000000 | |
| GOTO/SETPT | |
| PRINT/3,ALL | |
| STOP | |
| FINI |
