Basic knowledge of machining technology

1. Analyze the drawings and determine the process. When the parts are processed on the CNC machine tool, the original data obtained by the merchandiser is the part drawing. According to the part drawing, the shape, dimensional accuracy, surface roughness, workpiece material, blank type and heat treatment condition of the part can be analyzed, and then the machine tool and cutting tool can be selected 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 to achieve reasonable processing routes, fewer cutting times and short processing hours. In addition, relevant technological documents should also be filled in, such as CNC machining process cards, CNC tool cards, and tool routing maps. 2. Calculate the coordinate value of the tool path According to the geometric size of the part drawing and the set programming coordinate system, calculate the movement path of the tool center and obtain all the tool position data. General numerical control systems have the functions of linear interpolation and circular interpolation. For the contour processing of relatively simple planar parts (such as parts composed of straight lines and arcs), it is only necessary to calculate the starting point, end point, and arc of the geometric elements. The coordinates of the center of the circle (or the radius of the arc), the intersection or tangency of two geometric elements. If the CNC system has no tool compensation function, it is necessary to calculate the coordinate value of the tool center's motion track. For parts with complex shapes (such as parts composed of non-circular curves and surfaces), it is necessary to use straight line segments (or arc segments) to approximate the actual curve or surface, and calculate the coordinates of its nodes according to the required machining accuracy. 3. Compilation of parts processing program According to the processing route, the tool movement trajectory data, the determined process parameters and auxiliary actions are calculated, and the programmer can write the processing program of the part segment by segment according to the functional instructions and program segment format specified by the CNC system used. When writing, you should pay attention to: first, the standardization of program writing should be easy to express and communicate; second, on the basis of being fully familiar with the performance and instructions of the CNC machine tool used, the skills used in each instruction and the skills of program segment writing.