电子教案统一模板[数控]Unit2.ppt

Unit 2 NC/CNC Machining Equipment ;2.1 Lesson 3 Types of CNC Machining Centers ; Turning centers with increased capacity tool changers are also making strong appearance in modern production shops.[3] These CNC machines are capable of executing many different types of lathe cutting operations simultaneously on rotating part. In addition to machining centers and turning centers, CNC technology has also been applied to many other types of manufacturing equipment. Among these are wire electrical discharge machines (WEDM) and laser cutting machines. ; WEDM machines utilize a very thin wire as an electrode. The wire is stretched between two rollers and cuts the part like a band-saw. Material is removed by the erosion caused by a spark that moves horizontally with the wire. CNC is used to control horizontal table movements. WEDM machines are very useful for producing mold inserts, extrusions and trim dies as well as form tools. [4]; Laser cutting CNC machines utilize an intense beam of focused laser light to cut the part. Material under the laser beam undergoes a rapid rise in temperature and is vaporized. If the beam power is high enough, it will penetrate through the material. Because no mechanical cutting forces are involved, lasers cut parts with a minimum of distortion and have been very effective in machining slots and drilling holes.;2.2 Lesson 4 CNC Turning Center ;1. Roughing and finishing cuts in one pass 2. Machining different diameters on a shaft simultaneously 3. Finish turning and threading simultaneously 4. Cutting two different sections of a shaft at the same time When the turning center is equipped with a steady-rest, operations such as facing and threading may be performed on the end of a shaft.; The most complex CNC machine tools are the turning center, shown in Figure 2-1(The typical turning center with a ten-station turret that accepts quick-change tools). The majority of NC/CNC machine tools are equ