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 cutting depth, which leads to an increase in machining cutting force, which may cause static deviation between the workpiece and the tool, which in turn causes parts The accuracy of the shape becomes worse or the machining process is unstable, and it will also accelerate the wear of the tool. For this reason, the machine tool used for titanium alloy processing must have high power and the best possible static and dynamic characteristics (static and dynamic stiffness is high); 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 heat generated during machining to the tool. In order to improve the rigidity of the machine tool, some machine tool manufacturers use welded steel structures in the box structure or closed frame; the feed shaft uses high power Feed motor drive and high rigidity gapless guide system can be clamped to the machining position to further improve the rigidity of the machine; in addition, the entire system including the spindle-tool-link part and the tool holder holder must be improved. Stiffness during processing
In addition to the static stiffness, the dynamic characteristics of the machine tool are also decisive for the effective titanium alloy processing. 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 large cutting forces, low speeds, and excitation frequencies 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 (there are chatter marks), this 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. They can also actively adopt anti-vibration pads on the machine tool, and place parameters in the machine tool control device to avoid the rotation range of the limit cutting depth Vibration measures to further improve the seismic resistance of the machine tool.
The cutting of titanium alloy belongs to powerful cutting, so the tool spindle of the machine tool should have a large driving power and have a powerful powerful cutting function. In the aviation industry, the processing 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 allow a large amount of high-pressure cooling lubricant to 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 processing area in time, so as to prevent the chips from being cut multiple times, which reduces the tool life and scratches the processing surface. In order to make the machine tool have a high-power cutting function, the German Heller company has 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.
In a word, machine tools for processing titanium require high power, high stiffness, large flow and high pressure cooling devices, and good accessibility.