模具设计与制造专业英语 黄义俊_ 电子教案统一模板(模具)Unit7.pptVIP

Unit 7 The CNC Machining Equipment 7.1 Lesson 17 Types of CNC Machining Equipment Machining centers are the latest development in CNC technology. These systems are equipped with automatic tool changers with the capability of changing up to 90 or more tools.[1] Many machining centers are also fitted with the movable rectangular worktables called pallets. The pallets are used to automatically load and unload work pieces. At a single setup machining centers can perform such operations as milling, drilling, tapping, boring, and so on.[2] Additionally utilizing indexing heads, some centers are capable of executing these tasks on many different faces of a part at specified angles. 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. These are wire electrical discharge machines (WEDM) and laser cutting machines and so on. 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, extrusion and trim dies as well as forming 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. They have been very effective in