In the process of machining parts, the clamping mode of the workpiece affects the machining accuracy and efficiency of the workpiece, so it is of great significance to choose the positioning datum of the workpiece reasonably. The selection of positioning datum not only has great influence on the processing quality of parts, but also can improve production efficiency. The positioning and datum of the workpiece should be consistent with the design datum to prevent over-positioning. The selected positioning datum should ensure accurate and reliable positioning.
2, choose the tool and cutting parameters
The selection of NC tools and the determination of cutting parameters not only affect the machining efficiency of NC machine tools, but also directly affect the machining quality. CNC turning tools are generally divided into three types: special-shaped turning tools, pointed turning tools and circular turning tools. Programmers must determine the cutting parameters of each process and arrange the arrangement order of tools reasonably.
3. Determine the feeding sequence and route.
Before NC machining, it is necessary to reasonably select the tool alignment point and determine the tool path. The tool alignment point can be set on the machined part, but it must be the reference position or the machined part. Tool path includes cutting trajectory, the tool moves to the cutting starting point, the tool cuts in and out, and returns to the cutting starting point or tool alignment point. Determining the feed path mainly lies in planning the feed path of rough machining and idle stroke. The surface used as a precision datum should be treated first; Connecting rod, box, bracket, base and other parts, should first process the plane used for positioning and the end face of the hole, and then process the hole.
4. Programming of NC machining program
The NC machine tool adopts the right-hand Cartesian coordinate system, and the programming origin should be selected in a position that is easy to find and check during machining. Generally speaking, the programming zero point of shaft parts is selected at the intersection of the rotating shaft and the end face of its machining surface. CNC programming is generally divided into two types, one is manual programming and the other is automatic programming. Manual programming includes analyzing part drawings, determining process, numerical calculation and compiling part processing program list. The input and inspection of the program are all done by workers. Automatic programming is the process of compiling NC machining program with computer.
In a word, the popularization and application of NC machining technology is a great change in China's machinery manufacturing industry, which has effectively promoted the development of current machinery manufacturing level, provided high-quality, high-safety and high-efficiency mechanical products for China's industrial development, and brought good promotion to social and economic development. In the NC turning of shaft parts, we should master every detail, analyze and solve every difficulty, so as to ensure the quality of the workpiece more effectively, make full use of the characteristics of NC technology and bring greater benefits.