The shape of the machined surface is usually made up of straight lines, circular arcs or other curves. Ordinary milling machine operators according to the requirements of the pattern. The relative position between the tool and the workpiece is constantly changed, and then the cutter speed is matched with the selected milling cutter, so that the workpiece can be machined by cutting the workpiece.
CNC machine tool processing is to cut the motion coordinates between the tool and the workpiece into the smallest unit quantity, that is, the minimum displacement. According to the requirements of the workpiece program, the CNC system can make the coordinates move a number of minimum displacement, so as to realize the relative motion between the tool and the workpiece, so as to complete the machining of the parts.
Besides the characteristics of ordinary milling machine, NC milling has the following characteristics:
1. The parts are adaptable and flexible, and the parts, such as the mold parts and the shell parts, can be machined and the shapes are very complex or difficult to control.
2. It can process parts that ordinary machine tools can not process or difficult to process, such as complex curve parts described by mathematical models and three-dimensional surface parts.
3. It can process parts after clamping and positioning.
4, the machining precision is high, the processing quality is stable and reliable, the pulse equivalent of the numerical control device is generally 0.001mm, the high precision CNC system can reach 0.1 mu m. In addition, the NC machining also avoids the operation error of the operator.
5, high production automation, can reduce the labor intensity of the operator. It is beneficial to automation of production management.
6, high production efficiency, CNC milling machine usually does not need special fixture, such as special fixture, when replacing the workpiece, only need to call the processing program, clamping tool and adjustment tool data stored in the numerical control device, thus greatly shortening the production cycle. Secondly, CNC milling machine has the functions of milling machine, boring machine and drilling machine, which makes the process highly centralized and greatly improves the production efficiency. In addition, the spindle speed and feed speed of CNC milling machine are continuously variable speed, so it is beneficial to choose the best cutting parameters.