Computer Numerical Control, CNC

Presentation on theme: "Computer Numerical Control, CNC"— Presentation transcript:

1 Computer Numerical Control, CNC
Su-Jin Kim Mechanical and Aerospce Engineering Gyeongsang National University 1

2 Angular motion axis 회전축
Angular motion axis = Revolute joint Hyundai Robotics: Doosan Robotics:

3 Element & Kinematics Actuator: Motor  Gear  Bearing + Arm
Joint space (θ, d) Kinematics Cartesian space (X, Y, Z, A, B, C) Y0 X0 d1 θ1 d2 θ2 θ6 d6 Y6 X6 Z6 Daedong Gear : GMB Bearing:

4 Linear motion axis 직선축 Linear motion axis = Prismatic joint
Actuator: CNC  Motor  Ballscrew  Table Sensor : CNC  Encoder Motor Coupling Bearing Table Nut Ballscrew Encoder Guideway

5 Kinematics Joint space (d) Kinematics Cartesian space (X, Y, Z) dz
dx dz dy

6 Angular vs. Linear units
Characteristics Angular motion axis Linear motion axis Space O X Force, Stiffness, Prec Complex Complex (Orientation) Simple (Position) Application Weld, Assemble Machining, Forming Price Low High

7 Linear motion axis 직선축 Motor  Ballscrew  Table + Guideway
Coupling Bearing Table Nut Ballscrew Encoder Guideway CNC-Screw:

8 Index Guide way Ball screw Motor

9 Guideway 안내면 Linear motion bearing Sliding guideway
Hydrostatic guideway Air bearing

10 LM Bearing 직선운동 베어링 Linear Motion Bearing = LM Guide LM가이드
Rail + Ball or Roller + Block Standard element Rail Block Ball bearing SBC Linear :

11 LM Bearing Stiffness 200 N/μm, Small friction 10 N, Low damping
LM Bearing : (15min)

12 Sliding guideway 미끄럼 안내면
Rail – Turcite 타가이드 – Table High stiffness 500 N/μm, Large friction, High damping, Slow speed y z

13 Hydrostatic guideway 유정압 안내면
Hydrostatic guideway = Hyd. linear bearing High stiffness 500 N/μm, Low friction 1 N, High damping, Precise Pad Table Pump Rail Hydrostatic guide way:

14 Air Linear Bearing Aerostatic force
Lowest stiffness, Smallest friction, Precise(Surface average effect), High speed Clean display fab, CMM Rail Table Air Air linear bearing : CMM :

15 Characteristics Properties LM bearing Sliding Hydrostatic Air
Stiffness Middle High Very high Low Friction Very large low Very low Precision Poor Prec Cost Cheap Very expen Expen Application Standard Old Heavy Pre Clean Pre

16 Straightness 진직도 Rail straightness

17 Preload 예압 Stiffness ↑ 강성  Precision Friction ↑ 마찰 Displacement
Load (Force)

18 Ball Screw 볼스크류 Rotation  Linear motion Position accuracy
Hydraulic cylinder Ball screw Rack and pinion

19 Ball screw Angular (rev)  Linear (Lead mm) motion
Precise, Lead ↓  Force↑, Speed↓ TIC:

20 Rack and pinion Long distance, Not precise Assembly, Welding robot
SBC Linear :

21 Hydraulic cylinder High pressure Hydraulic 유압, Air 공압
Low precision, Poor efficiency Pump Tank DCV Actuator Filter

22 Lead error 리드오차 Nominal travel line Actual travel curve
Tolerance on useful travel Travel deviation Permissible travel variation Actual mean travel line

23 Motor 모터 Electric Current + Magnet (neodymium)  Mechanical torque
Stepper motor Servo motor Linear motor

24 Stepper motor Pulse  Angle, Easy, Small torque
Open loop control, Connected to PC by USB How step motor works? Stepping Motor

25 Servo drive & motor Current + Magnet  Torque, Efficiency > 90%
Closed loop control, Encoder, EtherCAT How servo motor works? Higen Motor : LS Mecapion:

26 Linear motor Fast linear motion Close loop control, Linear encoder

27 Servo vs. Stepper motors
Characteristics Servo Stepper Torque Flexible Poor acceleration Speed Smooth High Step Slow Control Closed loop Open loop Price Expensive Cheap Applications Smooth operations Standstill

28 Spindle Hwachoen built in spindle:

29 Summary LM bearing Ball screw Servo Motor Spindle

30 Reference SBC Linear: http://www.sbclinear.co.kr
TIC: Higen Motor : LS Mecapion:

31 CNC control 수치제어 CNC  Servo driver  Servo motor  Ball screw  Table + Guide way Servo motor Ball screw Guide way CNC Servo driver Machine tools CNC-Screw: 생산성과 품질 향상을 위한 가공장비의 정밀화 및 고속화 1940년대 NC(CNC)의 개발로 자동화 실현 (Closed CNC) 전통적인 폐쇄형 CNC에서 IT기술의 발전에 따른 고객의 요구로 CNC의 개방화 가속 컴퓨팅능력(계산속도, 데이터 양)과 센서기술의 발전으로 지능화 실현 단계  (완전) 무인화

32 CNC CNC (Computer Numerical Control)
1948 : Parsons & MIT developed 1st NC 2000 : PC-NC & Intelligent CNC 수동선반, 밀링머신 NC 개발 CNC 개방화 CNC 지능화 Ethernet Open CNC I/F Open CNC API 생산성과 품질 향상을 위한 가공장비의 정밀화 및 고속화 1940년대 NC(CNC)의 개발로 자동화 실현 (Closed CNC) 전통적인 폐쇄형 CNC에서 IT기술의 발전에 따른 고객의 요구로 CNC의 개방화 가속 컴퓨팅능력(계산속도, 데이터 양)과 센서기술의 발전으로 지능화 실현 단계  (완전) 무인화

33 International FANUC(Japen) 70% > Siemens(Germany) 20% >
Mitsubishi, Heidenhain, CSCAM, Doosan, Sentrol 10% Fanuc 30i SINUMERIK 840D

34 CSCAM HX2.0 KAIST  TurboTech (1990s)+CSCAM
Full Software CNC + Servo driver and motor CSCAM : CNC Servo:

35 CSCAM Step Software CNC + Stepper motor

36 SENTROL 353 1985 Developed CNC device “TEPS" for the first time in Korea Centrol:

37 Doosan D300 PC based CNC with multi-CPU
Visualization of tool path and workpiece Doosan D300:

38 Doosan Sketch-turn Conversation program for Turning center
Various machining pattern for turning & milling Easy access and simplified input

39 Interpolation 보간 Commend  Interpolation  Acceleration dec.  Actual, Corner blending error t VY Vx X Y Interpolation Commend Acceleration G1 X100. F6000 Y100.

40 Feed forward control 선행제어
Acceleration deceleration before interpolation 보간전 가감속 Corner deceleration 코너감속 X Y G2 X100. Y-50. R80. t F Acceleration dec. Interpolation Vy Vx

41 5-axis CNC Tool center point control 공구선단제어 Transform plane 좌표계
Z TCP table tilting 5-axis:

42 Precision Error Geometric 기하학: Linear 직선, Angular 원호
Structure 구조 : Stiffness 간성, Thermal 열 Control 제어 : Vibration 진동, Control 제어 Measure (Sensor)  Compensation (CNC)

43 Geometric error Geometrical error (Element, Backlash)
Sol: Calibration by Ball bar or Laser interferometer Ball bar or Laser calibration :

44 Structure Force / Stiffness 강성  Deformation
Sol: Bearing, Preload, Box ㅁ shape Heat (Chip tool, Spindle, Motor, Bearing, Environment)  Thermal extension 열팽창 Sol: Symmetric, Insulate, Sensor compensate Thermal compensation :

45 Vibration & control Vibration 진동  Sensor  Spindle change
Control error 제어 : Feed forward control Vibration reduction:

46 Virtual Machine Simulation of machining process and machine tool operation Verification and optimization of machining process NCBrain: ㅇ가상생산(Virtual Manufacturing) 기술은 가공공정 및 장비운영 시뮬레이션 기술로, 전통 기계가공의 사전검증 및 공정최적화를 통해 미래공장을 실현하는데 필요한 기초기술임 - 영국의 MachineWorks와 Moduleworks는 가상가공 모듈(Module)을 CAM소프트웨어와 장비업체에 공급 - 미국 CGTech는 VeriCut을 항공기부품을 중심으로 세계에 사업화 - 한국 NCB는 NCBrain을 금형가공 분야에 사업화하고 5X개발

47 NCBrain EYE The Virtual machine in CNC has EYE scanning workpiece.
Prevent collision at manual and automatic control NCBrain EYE:

48 Smart Machine CAM + Simulation + NC Machine
3d model + 4 click  product Smart UAX : Paper:

49 Summary CNC control Japan German
CSCAM, Centrol, Doosan D300, Hyundai iTROL Interpolation, Error compensation Virtual machine, NCBrain EYE Smart machine

50 Reference Doosan: http://doosanmachinetools.com
CSCAM: (CNC) Centrol: (CNC) NCBrain: (Virtual Machine)