1. Analyze the pattern and determine the process
When processing parts on a CNC machine tool, the original data obtained by the craftsman is the part drawing. According to the part drawing, you can analyze the shape, dimensional accuracy, surface roughness, workpiece material, blank type and heat treatment status of the part, and then select the machine tool and tool to determine the positioning and clamping device, processing method, processing sequence and cutting amount size. In the process of determining the process, the command function of the CNC machine tool used should be fully considered, and the efficiency of the machine tool should be fully utilized, so that the processing route is reasonable, the number of tools is small, and the processing time is short. In addition, you should also fill in the relevant technical documents, such as CNC machining process card, CNC tool card, tool path map, etc.
2. Calculate the coordinate value of the tool path
According to the geometric dimensions of the part drawing and the programmed coordinate system, the movement track of the tool center is calculated, and all tool position data is obtained. General numerical control systems have the functions of linear interpolation and circular interpolation. For contour processing of relatively simple planar parts (such as parts composed of straight lines and circular arcs), only the starting point, end point and arc of geometric elements need to be calculated. The coordinate value of the center of the circle (or the radius of the arc), the intersection or tangent point of two geometric elements. If the CNC system has no tool compensation function, the coordinate value of the motion path of the tool center must be calculated. For parts with complex shapes (such as parts composed of non-circular curves and curved surfaces), it is necessary to approximate the actual curve or curved surface with a straight line segment (or arc segment), and calculate the coordinate value of its node according to the required machining accuracy.
3. Writing parts processing program
According to the processing route, the tool motion trajectory data and the determined process parameters and auxiliary actions are calculated. The programmer can write the processing program of the part piece by piece according to the function instructions and block format specified by the numerical control system used. When writing, pay attention to: First, the standardization of program writing should be easy to express and communicate; second, on the basis of fully familiar with the performance and instructions of the CNC machine tool used, the skills of each instruction and the skills of program segment writing.