(1) The dimensioning method on the part drawing should be adapted to the characteristics of CNC machining. On the machining drawing of precision parts, the dimensions should be quoted on the same datum or the coordinate dimensions should be given directly.
1. This labeling method is not only convenient for programming, but also facilitates the coordination between dimensions, which brings great convenience in maintaining the consistency of design benchmarks, process benchmarks, detection benchmarks and programming origin settings.
2. Since part designers generally consider assembly and other use characteristics in dimensioning, they have to adopt a locally scattered labeling method, which will bring a lot of inconvenience to process arrangement and CNC machining.
3. Since the machining accuracy and repeated positioning accuracy of precision parts are high, the use characteristics will not be destroyed due to large accumulated errors, so the local scattered annotation method can be changed to the same reference size or directly give the coordinate size labeling method.
(2) Calculate the base point or node coordinates during manual programming. In automatic programming, precision part machining needs to define all the geometric elements that make up the part outline. Therefore, when analyzing the part drawing, it is necessary to analyze whether the given conditions of the geometric elements are sufficient.
For example, arc and straight line, arc and arc are tangent on the drawing, but according to the size given in the figure, when calculating the tangent condition, it becomes the state of intersection or separation. Due to the insufficient conditions of the geometric elements constituting the machining parts of precision parts, it is impossible to start programming. When this happens, it should be resolved through consultation with the part designer.