The cutting of titanium alloy belongs to powerful cutting, so the tool spindle of the machine tool must have a large driving power and have a powerful cutting function. In the aerospace industry, the machining of titanium alloy components is mostly cavity milling. To facilitate chip removal, the cooling and lubrication device must be managed. To facilitate chip removal, the cooling and lubrication device must be managed to make a large amount of high-pressure cooling lubricant directly spray the cutting tool blade. In this way, on the one hand, the tool is cooled, on the other hand, the chips can be better washed out of the machining area in time, so as to prevent the chips from being cut multiple times, which reduces the tool life and scratches the machining surface. In order to make the machine tool have a high-power cutting function, the German Heller company designed the machine tool structure and coordinate axis structure in a targeted manner, and equipped with a powerful cutting swing unit with excellent rigidity to install the tool spindle, so that the machine tool is vertical, horizontal and space. Any angle can produce the same cutting power.
The characteristics of titanium alloys are high strength and poor thermal conductivity. In order to achieve the cutting efficiency like machining aluminum, it is necessary to increase the cutting parameters as much as possible, that is, increase the gold feed and the cutting depth, which leads to an increase in the machining cutting force, which may cause a static deviation between the workpiece and the tool, which in turn causes parts The accuracy of the shape is deteriorated or the machining process is unstable, and the wear of the tool is also accelerated. For this reason, the machine tool used for titanium alloy machining must have high power and the best possible static and dynamic characteristics (high static and dynamic stiffness); it also needs to be equipped with corresponding high-pressure cooling and lubrication equipment to process at low speeds and high torque Remove chips in time to reduce tool wear and reduce the heat generated during machining to the tool. In order to improve the rigidity of the machine, some machine tool manufacturers use welded steel structures in the box structure or closed frame; the feed shaft uses high power The feed motor drive and high rigidity gapless guide system can be clamped to the machining position to further improve the rigidity of the machine tool; in addition, the entire system including the spindle-tool-link part and the tool holder holder must be improved. Stiffness during machining.
In addition to the static stiffness, the dynamic characteristics of the machine tool are also decisive for the effective titanium alloy machining. Controlling the stability of the machining process is a huge challenge. If the rigidity of the machine tool is low and the damping characteristics are poor, due to dynamic effects such as high cutting force, low speed and excitation frequency close to the natural frequency of the machine tool during cutting, self-excited vibration may occur, resulting in chattering during the machining process. In addition to affecting the quality of the workpiece surface (with chatter marks), this kind of chatter vibration can also cause overload and damage to the machine tool structure, tool tools and tools. Tool wear increases or even breaks. The stability of the machining process mainly depends on the selected spindle speed, cutting depth and other parameters. Users need to understand the performance of the machine tool and the possible limit cutting depth, and can also actively adopt vibration damping pads on the machine tool, pre-set parameters in the machine tool control device to avoid the rotation range of the limit cutting depth, etc. Vibration measures to further improve the seismic resistance of the machine tool.
