05 sisprod - computer numerical control

8/11/2019 05 Sisprod - Computer Numerical Control

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COMPUTER NUMERICALOMPUTER NUMERICAL

CONTROLONTROL

Presentasi KuliahTKI-313 Sistem Produksi

Jurusan Teknik Universitas Muhammadiyah Surakarta

Dosen : Much Djunaidi


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Types of AutomationManufacturing

Automation

Hard/ Rigid/ Mechanized

Automation

Soft/ Flexible/ Programmable

AutomationCopy m ng mac nes

Automats

Special purpose machines

CNC Mac nes

Robots

Automatically Guided Vehicles (AGVs)

Reconfigurable conveyors

Unlimited muscle powerSpeed

AccuracyUnmanned operationFlexibilitySimplified generic tooling even for the most complex jobs

Advantages of Soft

Automation


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CNC - Pengantar

Secara konvensional, operator menentukan dan mengaturberbagai parameter mesin, seperti kecepatan pemakanan

(feed), kedalaman (depth of cut ), dsb, tergantung jenis

pekerjaannya, dan mengendalikan pergerakan dengan

tangan.

,

dengan motor menggunakan computer programs.

Fungsi dasar dari CNC machine adalah pengendalian

gerakan secara automatic,precise, dan consistent.

Dua jenis sumbu yang biasa digunakan adalah linear

(driven along a straight path) dan rotary (driven along a

circular path).


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Why CNC is Accurate?

Light but rigid

construction

Hollow design with ribs to have less deflection and low

nat. freq., Design improvement using mode shape

analysis

Low inertia Keep weight of moving elements low

Low friction and play Guide way elements, Ball lead screws, Pre-loading

Good damping Appropriate material selection

effects

suspended dust too), Use of thermally stable material,

Thermal compensation

Advanced electrical and

electronics andcomputing

Advanced drives, Accurate sensors for position,

velocity, force, vibration, temp. etc., Sophisticatedfeedback control loops, Interpolators

Error compensations Axis calibration & pitch error compensation, Diameter

and length compensations, Adaptive control

Accurate manufacture Use of accurate manufacturing processes


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Defining Axes

Primary Secondary Tertiary

X U P

Y V Q

Z W R

Spindle is Z axis

Moving away is +

mag ne a e s a onary

Take longest as X axis


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Defining Axes

Lathe

Vertical Machining Center


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Important G CodesG00 Rapid Transverse

G01 Linear InterpolationG02 Circular Interpolation, CW

G03 Circular Interpolation, CCW

G17 XY Plane,G18 XZ Plane,G19 YZ Plane

G20/G70 Inch units

G21/G71 Metric Units

G40 Cutter compensation cancelG41 Cutter compensation left

G42 Cutter compensation right

G43 Tool length compensation (plus)

G43 Tool length compensation (plus)

G44 Tool length compensation (minus)

G49 Tool length compensation cancelG80 Cancel canned cycles

G81 Drilling cycle

G82 Counter boring cycle

G83 Deep hole drilling cycle

G90 Absolute positioning

G91 Incremental positioning


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Important M Codes

M00 Program stop

M01 Optional program stop

M02 Program end

M03 Spindle on clockwise

M04 Spindle on counterclockwise p n e s op

M06 Tool change

M08 Coolant on

M09 Coolant off

M10 Clamps on

M11 Clamps off

M30 Program stop, reset to start


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Modal and Non-Modal Commands

Modal commands: Commands issued in the NCprogram that will stay in effect until it is changed by

some other command, like, feed rate selection, coolant

selection, etc.

Non-modal commands: Commands that are effective

subsequent commands, like, a dwell command which

instructs the tool to remain in a given configuration for a

given amount of time.


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Open Loop and Closed Loop System


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Tape Preparation

Punch holes in channels 6and 7 pulse numeric value

Punch holes in channels 7pulse numeric value

Punch holes in channels 6pulse numeric value

1= a

2= b

3=c

1= j

2= k

3=l

2= s

3=t

4=u

5=e

6=f

7=g

8=h9=i

5=n

6=o

7=p

8=q9=r

6=w

7=x

8=y

9=z


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Programming : Absolute and Incremental

5 Parity check

6 Zero

7- Minus

8 End of info

EIA ASCII


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Features of a CNC Systems

The tool or material moves.

Tools can operate in 1-5 axes.

Larger machines have a machine control unit (MCU)

.

Movement is controlled by a motors (actuators).

Feedback is provided by sensors (transducers)Tool magazines are used to change tools

automatically.


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Types of Interpolations

Point to Point - No contouring capability

Straight cut control - one axis motion at a time is

controlled for machining

Contouring - multiple axiss controlled simultaneously


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Sample Programming

Preparatory Information: units, incremental or absolute positioning

Coordinates: X,Y,Z, RX,RY,RZ

Machining Parameters: Feed rate and spindle speed

Coolant Control: On/Off, Flood, Mist

Cycle Functions: Type of action required

Miscellaneous Control: Spindle on/off, direction of rotation, stops for

part movement

This information is conveyed to the machine through a set of

instructions arranged in a desired sequence Program


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Sample Programming

Manual Part Programming: Manual programming of themachines

Computer Aided Programming (CAP): Programming

done by a computer

Manual Data Input (MDI): A manual program is entered


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Sample Programming

Tool size = 0.25 inch,

p2

52.5

1

p3p4

p5

Feed rate = 6 inch per minute,

Cutting speed = 300 rpm,

Tool start position: 2.0, 2.0

Programming in inches

(4, 4)

(2, 2)

5

p0

p1

45

Motion of tool:

p0 p1 p2 p3 p4 p5 p1 p0


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Sample Programming

p2

5

2.5

1

p3p4

p5

Set up the programming

parameters

Programming in inches

Spindle CCW

(4, 4)

(2, 2)p0

p1

45

N010 G70 G90 G94 G97 M04

Use absolute coordinates

Spindle speed in rpm

Feed in ipm


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Sample Programming

p2

5

2.5

1

p3p4

p5Set up the machining

conditions

Machine moves in XY-plane

Use full-circle interpolation

Flood coolant ON

(4, 4)

(2, 2)p0

p1

45

N020 G17 G75 F6.0 S300 T1001 M08

Feed rate

Tool no.

Spindle speed


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Sample Programming

p2

5

2.5

1

p3p4

p5

Move tool from p0 to

p1 in straight line

Linear interpolation

target coordinates

(4, 4)

(2, 2)p0

p1

45

. .


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Sample Programming

p2

5

2.5

1

p3p4

p5

Cut profile from p1 to p2


(4, 4)

(2, 2)p0

p1

45

N040 G01 X3.875 Y9.125

target coordinates

N040 G01 Y9.125

X-coordinate does not change no need to program it

or


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Sample Programming

p2

5

2.5

1

p3p4

p5

Cut profile from p2 to p3

N050 G01 X5.634 Y9.125


target coordinates

(4, 4)

(2, 2)p0

p1

45

1

p3

.125

(x, y)

(6.5, 9)

y = 9 + 0.125 = 9.125

(6.5 - x)2+ 0.1252= (1 - 0.125)2

x = 5.634


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Sample Programming

p2

5

2.5

1

p3p4

p5

Cut along circle from p3 to

p4

circular interpolation, CCW motion

coordinates of center of circle

(always in incremental )

(4, 4)

(2, 2)p0

p1

45

target coordinates

N060 G03 X7.366 Y9.125 I0.866 J-0.125


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Sample Programming

N010 G70 G90 G94 G97 M04

N020 G17 G75 F6.0 S300 T1001 M08

N030 G01 X3.875 Y3.698

N040 G01 X3.875 Y9.125

Complete Programming

. .

N060 G03 X7.366 Y9.125 I0.866 J-0.125

N070 G01 X9.302

N080 G01 X3.875 Y3.698

N090 G01 X2.0 Y2.0 M30


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Adaptive Control

1. Adaptive control with constraints

2. Adaptive control with optimization


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Disadvantages

Increase in electrical maintenance

High initial investmentHigher per-hour operating cost than traditional machine

tools

Retraining of existing personnel

NC is a general term used for Numerical Control. CNC

refers specifically to COMPUTER NUMERICAL CONTROL.

CNC machines are all NC machines but not all NC

machines are CNC machine.


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Applications

Traditional machining Turning, boring, milling, grinding etc. Sheet metal manufacture

Turret punch press, pipe bending, flow forming etc.

Non-traditional machining

Wire-EDM, water-jet cutting, electron beam machining, laser, .

Coordinate Measuring Machines

Drafting machines

Robots

Rapid Prototyping (RP) machines

NC is a control technique; not a process


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END

05 sisprod - computer numerical control

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