【正文】 servodrive. It is characterized as a system that lacks feedback . That is , once an input control signal is sent , there is no sensing device to confirm the action of the control signal. Driving circuit Stepping motor Worktable Leadscrew Pulse train . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Types of NC ServoDrive System HalfClosedLoop ServoDrive It is characterized as a system that the indirect feedback monitors the output of this method is popular with NC systems, it is not as accurate as direct feedback, The halfclosedloop system pares the mand position signal with the drive signal of the servomotor. . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Types of NC ServoDrive System HalfClosedLoop ServoDrive Position pare circuit Speed control circuit Worktable Instruction Speed feedback signal Position feedback signal Leadscrew Servomotor . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Types of NC ServoDrive System ClosedLoop ServoDrive It is characterized as a system that the direct feedback monitors the output of servomotor. A feedback sensor directly measures the position of worktable. With its drive signal originated by the worktable, It is the preferred system because it monitors the actual position of the worktable on which the part is mounted. It is more accurate。 (2)the machine control unit。 (5)the mechanical machine tool unit . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Basic Components of NC Machine Tools The general relationship among the five ponents is illustrated in the below. . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Basic Components of NC Machine Tools The input media contains the program of instructions, it is the detailed stepbystep mands that direct the actions of the machine tool。 thus twoaxis control is laser cutting machines can cut holes in preformed sheet metal stock, requiring four or five axis control. . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Application of CNC NonMachine Tool Application Tube bending machine (數(shù)控彎管機 ) Automatic tube bending machines are programmed to control the location and the angle of the applications include frames of bicycles and motorcycles. . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL FEATURES OF NC AND ITS APPLICATIONAREAS Advantages and Disadvantages of NC NC has many benefits and advantages over manual production methods, but NC is more sophisticated technology than conventional production methods. . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Advantages and Disadvantages of NC Advantages of NC (1)Greater accuracy and repeatability (2)More plex part geometries are possible (3)Nonproductive time is reduced (4)Lower scrap rates (5)Inspection requirements are reduced (6)Engineering changes can be acmodated more gracefully . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Advantages and Disadvantages of NC Advantages of NC (7)Simpler fixtures are needed (8)Shorter manufacturing lead times (9)Reduced parts inventory (10)Less floor space required (11)Operator skilllevel requirements are reduced . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Advantages and Disadvantages of NC Disadvantages of NC (1)Higher investment cost (2)Higher maintenance effort (3)Part program (4)Higher utilization of NC equipment . Chapter 1 INTRODUCTION TO NUMERICAL CONTROL Application Areas for NC Machine Tools NC is best suited to relatively low volume runs of plex and varied ponents .NC can also be used to produce large numbers of plex ponents and /or small numbers simple ones. 謝謝觀看 /歡迎下載 BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES. BY FAITH I BY FAITH