3.1 General Configuration Technologies
Historically, lathes have been the most “conservative” machine tools, being mostly used as general purpose machines and, until some years ago, to perform pure roughing processes. Finishing operations were performed by grinding, honing or polishing.
Nevertheless, the latest most advanced machines, i.e., both high production lathes and turning centres, incorporate the same high level mechatronic technologies as other machines such as grinding machines or machining centers.
● The architecture of machines has been described in the previous section. There is no other machine tool that has undergone so much evolution, from the conventional lathe configuration the complex turning centers with several headstocks, turrets and milling heads, combining other tools such as laser, roller burnishing or ultrasonic sources. Machine architecture has evolved to adapt all 数控车床外文文献及文献翻译 第4页
these innovations.
●Guiding systems have progressed from the friction sliding guides of conventional lathes to a massive use of recirculating ball or roller units, pushed by the drastic increase in speed and acceleration required for faster machining, loading and unloading operations.
In heavy-duty and high precision machines, such as vertical lathes and turning centers orientated to aeronautic and energy applications, hydrostatic guides are used in rotary and displacement axes, providing a high load capacity, high damping ratios and positioning accuracy that provide safety, precision, stability and productivity to the high added value solutions of those sectors.
●Conventional motors for main spindles and transmissions have also been substituted by integrated electro spindles for headstocks and linear motors for displacement of axes when speed and acceleration requirements have become excessive for conventional transmissions.
●Numerical controls must also answer to the high demands the complexity level of these machines induces: multiple axes to be controlled and synchronized, different processes and machining cycles (turning, milling, grinding, drilling, tapping, etc.) to be programmed and controlled, and the high dynamics of axes and the implementation of measuring devices. Due to all these particularities, the latest generation controls are being applied and some manufacturers, such as Mazak, have developed or customized their own NCs.
3.2 Complementary Technologies to Improve
Machine Performance
In recent years, some complementary technologies have been integrated in lathes to improve the productivity and precision of these machines. Thus本文来自辣,文,论#文,网，www.751com.cn 加7位QQ324.9114找源文 of errors, in particular, vibrations and thermal effects. The “thermal friendly” concept is used by most of the leading manufacturers, with similar approaches that cover, basically, two fields: structural design, attempting to reach minimum thermal sensitivity designs, and the measurement of critical temperatures to apply compensation strategies through the NC.
Concerning vibration prevention, there are several approaches. Some manufacturers have developed strategies to suppress chatter vibrations, by the application of mechanical passive dampers or software based strategies such as the variation of the rotation speed.
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