机械制造技术基础课件-chapter4-section1(new).pptx
Chapter 4 Machine Tools and Machining Operations for rotational parts,Abstract Machine parts are basically separated into two: rotational parts and non-rotational parts. This chapter will focus on the required machine tools, cutting tools and machining operations for rotational parts. The lathes and lathe cutting tools, including main mechanism of CA6140 and the structure of turning tools are introduced. In the same time, the work principle of the machining methods of grinding, some hole-produced machines and cutting tools, are also introduced .,machining of rotational parts (a) Track Machining (b) forming method,Key words,Name of machine tools: Lathe (车床), screw thread machine (螺纹机床), Grinding machine(磨床), boring machine(镗床), drilling machine(钻床), broaching machine(拉床). Methods of shape generation: Turning, Taper turning, boring （镗孔）, drilling, core drilling（扩孔）, counter boring（锪孔）, reaming（绞孔）, grinding, Knurling（滚花）, threading,Lathe,Grinding Machine,Drill Press,4.1 Lathes and lathe cutting tools,4.2 Grinding machines,4.3 Hole making machine tool and cutting tool,Index,4.4 Process analysis of rotational parts,4.1 Lathe and Lathe Cutting Tools,4.1.1 turning operation Lathe is mainly used to produce parts in round shape. It removes material by rotating the workpiece against a single-point cutter, while the latter feeds linearly. Operations that can be performed on a lathe: a). Straight turning b). Taper turning c). Profiling d). Facing e). Turning and external grooving f). Face grooving g). Form cutting h). Boring i). Drilling j). Cutting off k). Threading l). Knurling Lets take CA6140 lathe as the example. It is very typical among the common lathes.,Typical machining by lathe,discussion,Think about: Could a non-rotational part be machined by turning method ? Why?,Types of lathe： 1.普通车床、落地车床；(Engine lathe/ ground lathe) 2.立式车床；(Vertical lathe) 3.转塔（六角）车床；(Turret lathe) 4.多刀半自动车床；(Semi-automatic lathe) 5.仿形车床及仿形半自动车床；(Profiling lathe) 6.单轴自动车床；(single-axis automatic lathe) 7.多轴自动车床及多轴半自动车床；(Multi-axis automatic lathe) 8.专门化车床 (special-purpose lathe),CA6140型普通车床外形图,(3) The main structure of CA6140, Headstock Main functions: Supporting, driving, stopping, changing direction, braking, and changing the speed of the principle axis，and transferring the motion from the principle axis to the feed system. Main mechanism and parts: the unload belt carrier, bi-directional multi-chip frictional clutch and speed change operating mechanism.,The Headstock structure of CA6140,Apron（溜板箱） Main functions: transfer the feed or rapid movement motion from feed box or quick-moved motor to the carriage, and make the carriage move longitudinally and transversally in positive or negative direction. The main mechanism：a pair of half nuts, feed mechanism in longitudinal and transversal direction, operating mechanism for quick move ,lock mechanism, safe clutch.,4.1.2 Types and the main technical Parameters of Lathe main technical Parameters of Lathe Max. diameter to be turned Maximum distance between headstock and tailstock Power of main motor Maximum rotation speed,the types of Lathe copying lathe automatic lathe thread cutting lathe turret lathe CNC Lathe,Other Lathes,turret Lathe,CNC Lathe,4.1.4 lathe cutting tool,main types of turning tool,1- facing cutter；2- profiling cutter； 3- grooving cutter ； 4-external cylindrical lathe cutter；5- threading cutter,It is used to machine round parts, inner holes, end surface, thread ,and tooth. The main types are shown as :,Lathe tool can be divide into integral turning tool、welded tool、clamped tool and rotation-able tool according to the structure.,Classification and comparison of turning tool：,welded tool,Advantage：simple structure、compact；rigidity、shock resistance; easy to produce and use.,disadvantage ： worse capability of cutting 、non-recycled tool bar 、longer setup time.,Rotation-able tool Advantage：long tool life, high efficiency, help to spread new technique and technology and lower tool cost. Attention: position (accurate or not), clamping (secure or not), chip flow (smooth or not), change and setup (easy or not),Machine-Clamped tool,Formingtool,Advantage： recycled tool bar, long tool life Attention: position (accurate or not), clamping (secure or not), chip flow (smooth or not),Advantage： high efficiency, easy to use Attention: difficult to produce, higher tool cost,4.1.5 lathe fixtures or turning fixtures,
