1、中文 3920 字 附录 A： 英文资料 Ultra- high-speed profiler for aircraft part machining DHP -120B: development goals and performance Kazuya Tanaka Manager Designing Sect .II, Engineering Dept .I 1. Instruction It is generally said that the conditions surrounding the aircraft industry have been less than optimal
2、 since the terrorist attack of September 11, 2001, but the Japanese aircraft industry seems to be in a slightly different situation. This is observation is supported by the fact that the Defense Agencys “PX ”(advanced anti-submarine patrol plane) and “CX”(cargo transport plane) projects have been ap
3、proved ,and Boeing- and Airbus-related contract have not decline significantly .Thanks to these and other factors ,such as the fact that the industry is entering the equipment replacement phase ,the Japanese aircraft industry is currently in relatively good shape . Under the influence of the global
4、market needs ,there is very strong demand for reducing the costs of civil aircraft parts .To meet this demand ,aircraft manufacturers and job shops contracted to supply parts to them have been working hard to reduce cost and improve manufacturing technology and productivity . The number of aircraft
5、produced by manufacturers of small jet aircraft is increasing at a much faster rate than the number of aircraft produced by manufacturers more or less specializing in larger aircraft, such as Boeing and Airbus .Despite the steady growth of demand, job shops under contract with these aircraft manufac
6、turers are being faced with increasing pressures for cost reduction. The emergence of southeast Asian countries capable of producing parts at low coast has made price competition fiercer .The Chinese aircraft industry is bursting with energy because job shops in China can now compete with Japanese j
7、ob shops in lead time and quality in addition to being able to produce parts at lower coasts . Given these global trend trends, it can be said that the Japanese aircraft industrys position is delicate in the competitive market .In spite of lead-time and quality superiority, the Japanese aircraft ind
8、ustry is fighting a steeply uphill battle in price competition. To help cope with the situation as a machine tool manufacturer, SNK has developed DHP-120B, an advanced 5-axis ultra-high-speed horizontal profiler that is at once most cost-effective and highly productive .The rest of this article intr
9、oduces the new profiler. 2. Background: Brief History of Profiler Development at SNK Since the development of SM-13 Spar Mill (with 13 numerically controlled axes ) in 1967, SNK has developed many machine tools designed for aircraft parts machining and five-axis profilers, and delivered many machine
10、s to specialty job shops both in Japan and abroad . One of the larger machines recently developed and delivered is a two-gantry, A&B-axis-type, three-spindle five-axis profiler with a 64-meter-long bed with a 4-meter-wide working surface (Photo 1).As shown in Photo 1, these profiler are vertical spi
11、ndle machines that enable the operator to set up a large workpiece on the bed in a stable position . As time passed ,however ,the way aircraft parts are manufactured has changed :machining of forgings ,which used to be the method of manufacturing aircraft parts ,began to be replaced by the method of
12、 machining complex parts out of solid material in order to reduce the number and weight of parts .This meant removing most of the material during machining .Use of high-speed machining ,which is designed to increase productivity ,also dramatically increased the volume of metal removed per hour ,maki
13、ng vertical spindle machines an unrealistic choice from the standpoint of chip removal. To meet the changing needs, SNK developed HPS-4B (Photo 2), a large 5-axis high-speed, horizontal ,tilting-table type profiler designed specifically for high-speed machining of complex parts out of solid material
14、 ,easy setup and efficient chip removal .The new machine was put on exhibit at the 1998 Chicago show and was hailed by aircraft parts job shops. Since, however ,HPS-4B is a large machine with a 210m machine envelope, it was too large and too expensive for smaller job shops. To demonstrate the superi
15、or of the machine concept and easy operator offered by this type of machine, SNK developed a machine based on a similar concept .This machine, HPS-120B, is a compact and reasonably-price 5-axis high-speed horizontal profiler (Photo 3) and was exhibited at the 2000 Chicago show .This machine was accl
16、aimed for its performance and economy and has now become one of the greatest value-added models of the SNK profiler. Market needs ,however ,have changed rapidly ,and there has been increasing pressure for cost reduction ,as mentioned earlier .Recognizing the need for a high-speed profiler capable of
17、 performing machine with unprecedented efficiency ,SNK developed its newest 5-axis ultra-high-speed horizontal profiler ,UHP-120,that inherits the acclaimed features of the HPS series of profiler ,and put the machine on exhibit at the 2001 EMO show . 3. UHP-120B: Development Goals and Performance Th
18、e aim of development of UHP-120B is to offer to users a cost-effective machine that boosts productivity in the machining of medium- and small-sized parts of aluminum, a material widely used in aircraft applications. Using HPS-120B, which has proven performance in the field of high-speed machine, as
19、a base machine, SNK developed UHP-120B (Photo 4) through extensive research and development. The rest of this section introduces principal technologies incorporated into the new machine to achieve the goals of the machine. For information on the machines main specifications, please see New Product N
20、ews in this report. 1) Technology to achieve high productivity (1)Developing high-speed high-power spindle unit It is generally said that there is no limit to cutting speeds used in the machining of aluminum to manufacture aircraft parts .The key to increasing productivity in such machining is to fi
21、nd a way to achieve high metal removal rates at high cutting speeds. To this end, we developed a new 75kW, 32,000min -1, high-speed high-power spindle unit with a compact, powerful drive motor for the new profiler .This high-performance spindle unit ranks among the highest in terms of spindle speed
22、and power for the spindle configuration is equipped for HSK-E 63 tools according to user needs .The spindle bearings are equipped with an under-race lubrication system to enhance reliability of high-speed machining during long-time operation. (2)Increasing feedrates High axis feedrates and high acce
23、leration /deceleration capabilities are important factors directly affecting machining time and machining accuracy that can be achieved in high-speed machining .For the linear axes ,twin drive systems and tow-motor-drive mechanisms have been employed to increase the rigidity of the drive system ,to
24、increase feedrates and maximize acceleration/deceleration ,and to increase productivity .As a result ,the maximum cutting federates of 40m /min and 4800deg/min have been achieved for the linear axes ,respectively . We believe that UHP-120B ranks among the best in terms of spindle and axis and axis f
25、eed capability in the field of the machining of aluminum aircraft parts. (3)Minimizing moving masses Reducing the moving mass along each axis is an effective way to make axis movement faster and achieve a high level of dynamic responsiveness .UHP-120B has been designed as a moving ram type ,instead
26、of a moving column type ,machine ,the structural design has been optimized through minimization of the moving masses and computer-aided structural analyses to make the machine structure very light and stiff .The spindlehead and the spindlehead saddle installed on the Z-axis ram are made of a special lightweight alloy whose coefficient of thermal expansion is comparable to that of iron so as to reduce the weights of the moving parts and minimize
