Multi-axis machining technology for multi-axis machining

As the basis of modern mechanical manufacturing technology, CNC machining technology has greatly changed the mechanical manufacturing process. Compared with traditional machining technology, modern NC machining technology is significantly different in machining technology, machining process control, machining equipment and process equipment. The familiar CNC machine tools have XYZ three linear coordinate axes, and multi-axis means that there is at least a fourth axis on a machine tool. Usually, multi-axis NC machining refers to NC machining with more than 4 axes, with 5 axes as the representative. Multi-axis NC machining

The machine tool can control the linkage of more than four coordinate axes at the same time, and integrate the functions of NC milling, NC boring and NC drilling. After the workpiece is clamped once, the machined surface can be milled, bored and drilled, which effectively avoids the positioning error caused by repeated installation, shortens the production cycle and improves the machining accuracy. With the rapid development of mold manufacturing technology, higher requirements are put forward for the machining ability and efficiency of machining centers, so multi-axis NC machining technology has been developed unprecedentedly.

With the development of numerical control technology, multi-axis CNC machining center has been more and more widely used. Their greatest advantage is that it makes the processing of complex parts much easier, shortens the processing cycle and improves the surface processing quality. The improvement of product quality puts forward higher requirements for product performance. For example, the finishing of headlight mold: car headlights mold: processed by double turntable five-axis linkage machine tool. Due to the special optical effect requirements of headlight mold, many small curved surfaces used to reflect light require very high machining accuracy and smoothness, especially the smoothness, which almost requires mirror effect. With high-speed cutting technology and equipment and five-axis ball milling machine tool, it is easy to cut the mirror surface, but it is almost impossible to realize the backward processing technology in the past. Using five-axis linkage machine tool to process molds can quickly complete mold processing and deliver goods, better ensure the processing quality of molds, make mold processing easier, and make mold modification easier. In the traditional mold processing, the vertical machining center is generally used to finish the milling of the workpiece. With the continuous development of mold manufacturing technology, some weaknesses of vertical machining center itself are becoming more and more obvious. Ball-end milling cutter is widely used in modern die processing, which brings obvious benefits to die processing. However, if a vertical machining center is used, the linear velocity of its bottom surface is zero, so the smoothness of the bottom surface is very poor. If the four-axis and five-axis machine tool processing technology is used to process the mold, the above shortcomings can be overcome. Machining centers are generally divided into vertical machining centers and horizontal machining centers. The most effective machining surface of the three-axis vertical machining center is only the top surface of the workpiece, and the horizontal machining center can only finish the four-sided machining of the workpiece with the help of the turntable. Multi-axis NC machining center has the characteristics of high efficiency and high precision, and the workpiece can be machined on five surfaces at one time. If equipped with high-grade numerical control system with 5-axis linkage, it can also process complex spatial curved surfaces with high precision, which is very suitable for processing forming dies of automobile parts, aircraft structural parts and other workpieces. According to the form of rotating shaft, multi-axis NC machining center can be divided into two ways.

(1) table rotation axis.

The advantages of this multi-axis NC machining machine tool are: simple spindle structure, good spindle rigidity and low manufacturing cost. However, in general, the workbench cannot be designed to be too large and its bearing capacity is small, especially when the rotation angle of axis A is greater than or equal to 90, the workpiece will bring great bearing torque to the workbench when cutting.

(2) Vertical spindle head rotates.

The advantages of this multi-axis NC machining machine tool are: the spindle machining is very flexible, and the workbench can also be designed to be very large. When machining a curved surface with a spherical milling cutter, when the center line of the cutter is perpendicular to the machined surface, the surface quality of the workpiece cut by the vertex will be poor because the linear velocity of the vertex of the spherical milling cutter is zero. However, the design of spindle rotation makes the spindle rotate at an angle relative to the workpiece, so that the spherical milling cutter can avoid vertex cutting, ensure a certain linear speed, and improve the surface machining quality, which is difficult for the workbench rotary machining center to do. Multi-axis NC machining has the following characteristics:

(1) Reduce datum conversion and improve machining accuracy.

The process integration of multi-axis NC machining not only improves the effectiveness of the process, but also ensures the machining accuracy more easily because the parts only need to be clamped once in the whole machining process.

(2) Reduce the number of lamps and covers an area.

Although the price of single equipment in multi-axis NC machining center is high, the number of fixtures, workshop area and equipment maintenance costs are also reduced due to the shortening of process chain and the reduction of equipment quantity.

(3) Shorten the production process chain and simplify production management.

The complete machining of multi-axis CNC machine tool greatly shortens the production process chain, and because the machining task is only given to one job, it not only simplifies the production management and scheduling, but also obviously improves the transparency. The more complex the workpiece is, the more obvious its advantages are compared with the traditional production method with scattered working procedures. At the same time, due to the shortening of the production process chain, the number of products in process will inevitably decrease, which can simplify production management and thus reduce the cost of production management.

(4) Shorten the development cycle of new products.

For enterprises in aerospace, automobile and other fields, some new product parts and molding dies have complex shapes and high precision requirements. Therefore, the multi-axis NC machining center with high flexibility, high precision, high integration and complete machining ability can solve the problem of precision and cycle of complex parts processing in the process of new product development, greatly shorten the research and development cycle and improve the success rate of new products.