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

Angular motion axis 회전축 Angular motion axis = Revolute joint Hyundai Robotics: https://youtu.be/hvXGImTT5Jw Doosan Robotics: http://ma.gnu.ac.kr/vod/automatic/Robot_Doosan.mp4

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 : http://www.daedonggear.com GMB Bearing: http://www.gmb.co.kr

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

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

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

Linear motion axis 직선축 Motor  Ballscrew  Table + Guideway Coupling Bearing Table Nut Ballscrew Encoder Guideway CNC-Screw: http://ma.gnu.ac.kr/vod/Automatic/CNC_Fanuc.mp4

Index Guide way Ball screw Motor

Guideway 안내면 Linear motion bearing Sliding guideway Hydrostatic guideway Air bearing

LM Bearing 직선운동 베어링 Linear Motion Bearing = LM Guide LM가이드 Rail + Ball or Roller + Block Standard element Rail Block Ball bearing SBC Linear : https://youtu.be/ww7FebhbYT4

LM Bearing Stiffness 200 N/μm, Small friction 10 N, Low damping http://ma.gnu.ac.kr/paper/De-Jun_Cheng-Friction-LM-Roller.pdf LM Bearing : https://youtu.be/2I44OT7c_MY (15min)

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

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: https://youtu.be/nIccpUjQO90

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 : https://youtu.be/l2B12U6NtQw CMM : http://www.dukin.co.kr

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

Straightness 진직도 Rail straightness

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

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

Ball screw Angular (rev)  Linear (Lead mm) motion Precise, Lead ↓  Force↑, Speed↓ TIC: http://www.ticg.co.kr

Rack and pinion Long distance, Not precise Assembly, Welding robot SBC Linear : https://youtu.be/vTNKLOkWSlk

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

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

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

Stepper motor Pulse  Angle, Easy, Small torque Open loop control, Connected to PC by USB How step motor works? https://youtu.be/eyqwLiowZiU Stepping Motor http://ma.gnu.ac.kr/vod/Automatic/Step_Servo_Moter.wmv

Servo drive & motor Current + Magnet  Torque, Efficiency > 90% Closed loop control, Encoder, EtherCAT How servo motor works? https://youtu.be/hg3TIFIxWCo Higen Motor : http://www.higenmotor.co.kr LS Mecapion: http://www.lsmecapion.com

Linear motor Fast linear motion Close loop control, Linear encoder

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

Spindle Hwachoen built in spindle: https://youtu.be/iPsKk4kcVrE

Summary LM bearing Ball screw Servo Motor Spindle

Reference SBC Linear: http://www.sbclinear.co.kr TIC: http://www.ticg.co.kr Higen Motor : http://www.higenmotor.co.kr LS Mecapion: http://www.lsmecapion.com

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: http://ma.gnu.ac.kr/vod/Automatic/CNC_Fanuc.mp4 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

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

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

CSCAM HX2.0 KAIST  TurboTech (1990s)+CSCAM Full Software CNC + Servo driver and motor CSCAM : http://cscam.co.kr CNC Servo: http://ma.gnu.ac.kr/vod/automatic/CNC_CSCAM_Servo.mp4

CSCAM Step Software CNC + Stepper motor

SENTROL 353 1985 Developed CNC device “TEPS" for the first time in Korea Centrol: http://sentrol.net

Doosan D300 PC based CNC with multi-CPU Visualization of tool path and workpiece Doosan D300: http://ma.gnu.ac.kr/vod/automatic/CNC_Doosan_D300.mp4

Doosan Sketch-turn Conversation program for Turning center Various machining pattern for turning & milling Easy access and simplified input http://www.doosanmachinetools.com/kr/product/software/sketch-turn.do

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

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

5-axis CNC Tool center point control 공구선단제어 Transform plane 좌표계 Z TCP table tilting 5-axis: https://youtu.be/HxPjH4v5iEg

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

Geometric error Geometrical error (Element, Backlash) Sol: Calibration by Ball bar or Laser interferometer Ball bar or Laser calibration : https://youtu.be/PlydCw9_U2E

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 : https://youtu.be/ueQ48ogxYWM

Vibration & control Vibration 진동  Sensor  Spindle change Control error 제어 : Feed forward control Vibration reduction: https://youtu.be/K-HAJBhhTVA

Virtual Machine Simulation of machining process and machine tool operation Verification and optimization of machining process NCBrain: http://ncbrain.com 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

NCBrain EYE The Virtual machine in CNC has EYE scanning workpiece. Prevent collision at manual and automatic control NCBrain EYE: https://youtu.be/QhK_3boscQA

Smart Machine CAM + Simulation + NC Machine 3d model + 4 click  product Smart UAX : https://youtu.be/t7RMOzYfwfI Paper: http://ma.gnu.ac.kr/paper/De-Yu_Park_SmartMachineTool.pdf

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

Reference Doosan: http://doosanmachinetools.com CSCAM: www.cscam.co.kr (CNC) Centrol: www.sentrol.net (CNC) NCBrain: www.ncbrain.com (Virtual Machine)