Efficiency , quality is the main body of advanced manufacturing technology 。 High-speed, high-finishing technology can greatly improve efficiency, improve product quality and grades, and shorten the production cycle and improve market competitiveness。 To this end, Japan will study advanced technologies listed it as one of five major modern manufacturing technology, the International Institute of Production Engineering (CIRP) be identified as the 21st century, one of the central research directions。
In the car industry, the production of an annual output of 300,000 beat is 40 seconds / vehicle , and most varieties of processing is a car equipped with one of the key issues that must be addressed ; in aviation and aerospace industry, its processing parts are mostly thin-walled and thin bars, stiffness is poor, aluminum or aluminum alloy material , and only at high cutting speed and cutting force in the case of a small can of these ribs, the wall processing。 Recently, large single piece aluminum alloy billets 'hollowing out' approach to create the wings, fuselage and other large parts to replace multiple components through a large number of rivets, screws and other connecting means assembly, so that components of the strength, stiffness and reliability Improve 。 These are made of processing equipment , high speed, high precision and high flexibility requirements。
From the EMO2001 exhibition point of view, high-speed machining center feed speed up to 80m/min, or even higher, and air speed up to 100m/min or so。 At present many of the world automobile plant , including China's Shanghai General Motors , have adopted a high-speed machining center product line consisting of some combination of machine tool alternatives。 U。S。 CINCINNATI companies Hyper Mach machine feed rate of up to 60m/min, quick to 100m/min, acceleration up to 2g, spindle speed has reached 60 000r/min。 Processing of a thin-walled aircraft parts , only 30min, whereas the same high-speed milling machine parts in general need to 3h, in the general milling required to 8h; German DMG company's dual-spindle lathe spindle speed and acceleration respectively 12 *! 000r/mm and 1g。
In the processing precision , the past 10 years, the general level of processing precision CNC machine tools from 10μ m to 5μ m, Precision machining centers from the 3 ~ 5μ m, up to 1 ~ 1。5μ m, and the ultra-precision machining accuracy has begun to enter the nano-scale (0。01μ m)。
In terms of reliability, the MTBF value of foreign NC device has reached more than 6 000h, servo system MTBF value reached more than 30000h, showing a very high reliability。
In order to achieve high speed, high precision work, with supporting features such as spindle motor , linear motor has been rapid development of applications further。
1。2 5-axis simultaneous machining and rapid development of complex machine tools
5-axis machining of three-dimensional curved surface parts can be used the best tool for cutting geometry , not only finish high, but efficiency is greatly improved。 It’s generally believed that, 1 5-axis machine tools can equal the efficiency of 2 sets of 3-axis machine tools, particularly the use of cubic boron nitride and other super-hard materials , high-speed milling cutter hardened steel components, 5-axis simultaneous machining comparable three-axis process giving a higher efficiency。 But in the past due to 5-axis numerical control system, host complex structure and other reasons, its price than the 3-axis CNC machine tools are several times higher, plus the programming more difficult, limiting the development of five-axis machine tools。
Present, due to the emergence of spindle, allowing to achieve 5-axis simultaneous machining of composite spindle head structure greatly simplified and its manufacturing difficulties and costs significantly reduced, narrowing the gap between the price of CNC system。 Therefore, the promotion of the composite spindle head type five-axis machine tools and complex machining machine tools (including the 5-sided machining, machine tools) development。