Application scenarios and technical points of precision CNC broaching

Precision CNC broaching is mainly used in some parts processing fields that require extremely high shape accuracy and surface quality. In the automotive manufacturing industry, key engine parts such as valve guides and spline shafts often use precision CNC broaching technology. The valve guide requires a high-precision inner hole shape and an extremely smooth inner surface to ensure the smooth operation of the valve. Precision CNC broaching can process the inner hole to the required dimensional accuracy and surface roughness at one time, greatly improving production efficiency and product quality. In the aerospace field, precision CNC broaching also shows irreplaceable advantages for the mortise and tenon processing of the roots of some aircraft engine blades with complex shapes. It can accurately shape complex mortise and tenon contours according to design requirements, meeting the stringent requirements of aircraft engines for parts reliability under extreme working conditions such as high temperature, high pressure, and high speed.

There are many technical points for precision CNC broaching. The first is the design and manufacture of broaches. As the core tool of precision CNC broaching, the broach has a complex structure and extremely high precision requirements. The tooth shape of the broach needs to be specially designed according to the shape of the processed part, and the cutting angle, tooth lift and other parameters of each tooth are accurately calculated. For example, when processing internal splines, the tooth shape of the broach must perfectly match the tooth groove shape of the spline to achieve efficient and accurate cutting. At the same time, the material selection of the broach is also crucial. High-performance high-speed steel or cemented carbide materials are usually used to ensure sufficient hardness, wear resistance and toughness to withstand the huge cutting force and friction during the broaching process.

The CNC system plays a key control role in precision CNC broaching. It can accurately control the motion trajectory, cutting speed and feed rate of the broach. During the processing, the CNC system adjusts the position and motion state of the broach in real time according to the pre-written program. For example, when encountering uneven material hardness, the CNC system can automatically reduce the cutting speed or adjust the feed rate to avoid excessive wear of the broach or a decrease in processing accuracy. Moreover, the advanced CNC system also has a tool monitoring function, which can monitor the wear of the broach in real time. Once the broach wear exceeds the set range, it will promptly remind the operator to replace or adjust it.

The cooling and lubrication system is also an indispensable part of precision CNC broaching. Since a large amount of heat and chips will be generated during the broaching process, if cooling and lubrication cannot be carried out in a timely and effective manner, it will lead to rapid wear of the broach, reduced surface quality of the machined parts, and thermal deformation of the parts. Usually, a special cutting fluid is used, and the cutting fluid is accurately sprayed into the cutting area through a reasonably designed cooling and lubrication channel. The cutting fluid can not only take away the heat, but also play a lubricating role, reduce the friction coefficient between the broach and the workpiece, and reduce the cutting force, thereby further improving the processing accuracy and surface quality.

In addition, precision CNC broaching also has high requirements for the accuracy and stability of the machine tool. The bed of the machine tool needs to have sufficient rigidity to resist the cutting force during the broaching process and prevent the machine tool from vibrating and deforming. The positioning accuracy and repeat positioning accuracy of the worktable must meet extremely high standards to ensure the position accuracy of the workpiece during the broaching process.

As a type of intelligent machining, precision CNC broaching plays an irreplaceable role in specific application scenarios. Its technical key points cover broaches, CNC systems, cooling and lubrication systems, and machine tool accuracy. Each link cooperates and works together to achieve high-precision and high-efficiency parts processing, providing strong technical support for the development of many high-end manufacturing industries such as automobiles, aerospace, etc.