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DSCEBangalore – 78

MANUALDepartment of Mechanical

EngineeringCIM & AUTOMATION LAB: 10MEL78

CONTENTSPage No.

1. Introduction to CNC Turning, programs on turning 2

2. Introduction to CNC Milling, programs on Milling 32

3. CapsTurn and CapsMill 46

4. Simulation of Hydraulic and pneumatic circuits using LMS Image

Lab (AMESim) Software. 48

5. Exercise Problems 50

6. Definitions of FMS and ASRS 52

1




1. INTRODUCTION TO CNC TURNING, PROGRAMS ON TURNING

NC TECHNOLOGY

1.1 Numerical Control (NC):

It is the acronym for ‘Numerical Control’. Numerical Control refers to the use of coded

numerical information in the automatic control of equipment. NC can be defined as a kind of

programmable automation in which the process is controlled by numbers, letters & symbols. The

numbers letters & symbols are arranged as a ‘program of instructions’ for a particular job. Such a

program is called a part program.

NC can be applied to various operations in engineering, like drafting, machining, assembly,

inspection, etc. The main area of NC application is metal machining operations.

1.2 Basic Components of an NC System:

An NC system consists of three basic components.

1. Program of instructions

2. Machine control unit

3. Machine tool

Above Figure shows the block diagram of an NC machine. The program of instructions sends

commands to the Machine Control Unit, which in turn controls the machine tool.

1.3 NC Coordinate systems:

The relative movement of the machine tool spindle & worktable is due to the individual slides

being operated by instructions from the part program.

Normally, three slides are required in a NC machine tool.

Longitudinal

Vertical

Transverse

2

PROGRAM OF INSTRUCTIONS

MACHINE CONTROL UNIT MACHINE TOOL




The position and direction of movement of each slide is given by the right hand coordinate

system. Here we have three axes X, Y & Z mutually perpendicular to each other.

Position of axes: Usually the Z axis is located (positioned) along the machine tool spindle. The

X axis is positioned parallel to the machine worktable and perpendicular to the Z axis. The Y

axis is perpendicular to both Z & X axis.

Direction of axes: If the movement of the slide is such that the tool moves away from the work

piece, the direction of that slide axis is positive (+ ve). Similarly, if the movement of the slide is

such that the tool moves nearer to or into the work piece, the direction of that slide axis is

negative ( - ve).

Zero points & Reference points:

The accurate position of the machine tool slides with the machine tool is established by the ‘Zero

Point’. The Zero Points may be (a) Machine Zero Point & (b) Work Zero Point.

Machine Zero Point is specified by the manufacturer of the machine. This is the zero point for

the coordinate systems and other reference points in the machine.

Workpiece Zero Point determines the workpiece coordinate system in relation to the machine

zero point. This point is chosen by the programmer, and input into the CNC system when setting

up the machine. The position of this point can be freely chosen by the programmer within the

workpiece envelope of the machine. Its position is chosen such that the dimensions in the

workpiece drawing can be conveniently converted into coordinate values and also to effectively

take care about the clamping/chucking, setting up, etc.

Reference Point or Home Position serves for calibrating and controlling the measuring systems

of the slides and tool traverses. The position of the reference point is accurately predetermined in

every traverse axis by the trip dogs and the limit switches. Therefore the reference point

coordinates always have the same precisely known numerical values in relation to the machine

zero point. After initiating the control system, the reference point must always be approached

from all axes to calibrate the traverse measuring system.

Dimension System: Dimensional information in the work piece drawing can be stated in 2

methods – Absolute Dimensioning & Incremental Dimensioning.

In Absolute dimensioning, the coordinate data are taken with respect to a fixed reference point on

the workpiece drawing (usually the workpiece zero).

3




In Incremental Dimensioning, the coordinate data are taken with respect to the previous

coordinate value. i.e., every coordinate programmed will be the origin for the next coordinate to

be programmed.

1.4 NC & CNC: During the early period of NC technology, most of the control activities in the

controller were performed by electronic hardware devices like diode valves. The electronics

consisted of many mechanical devices which frequently posed problems of non-contact. The

machine tools and processes then controlled by such controllers were called as NC Machines.

With the improvement of technology and with the evolution of ‘integrated circuits’ mechanical

problems with electronic devices were solved. Also with the very fast development of

computers, almost all the control activities, performed by the hardware of the controller unit,

could then be tackled by software (programs). The machine tools and processes presently being

controlled by powerful computers is termed as CNC Machines. CNC is the acronym for

‘Computer Numerical Control’.

1.5 CNC Part Program:

It consists of a set of properly arranged sequence of instructions which when executed

initiates the controller to send various signals to different machine tool drives in accordance with

the program sequence so as to perform the desired work/job.

The CNC program (also called as the CNC part program) is made up of number of ‘lines of

instructions’. Each ‘line of instruction’ is called a Block. Each Block in turn consists of a few

‘alpha-numeric words’ called as ‘CNC Words’

Figure here shows a sample part program depicting the ‘Blocks’ and ‘CNC Words’.

Also, it may be noted that each CNC word starts

with a Word Address (upper-case alphabet) followed

by a numeric data.

Such a CNC program format is called ‘Word

Address Format’.

CNC Words: The different types of CNC words

used in CNC programming are as follows.

4




a) Sequence Number (N-word): It is used to identify a block.

b) Preparatory function word (G-code): This command prepares the machine controller to

follow a given instruction. E.g. G00 stands for Rapid Movement (point-to-point position)

c) Coordinate Data(X, Y & Z words): These words specify the coordinate position of the

cutting tool. E.g. X15, Y-40, Z-2

Coordinate Data may also contain the I, J & K words which specify the coordinate values

of the arc. I, J & K values are also called as the ‘interpolation parameters’.

d) Arc Radius (R-word): Instead of programming the interpolation parameters (arc-center-

coordinates) I, J & K, the arc radius can be programmed using the R-word.

e) Feed Rate (F-word): These words specify the feed rate of the tool in a machining

operation. It is usually expressed in mm/min. E.g. F30

f) Cutting Speed (S-word): These words specify the cutting speed of the tool/spindle

rotation in RPM. E.g. S1200

g) Tool Selection (T-word): This command is used to access a required tool from a tool

turret or an automatic tool changer. This command is usually used in CNC machines with

Automatic Tool Changing facility. E.g. T10 may specify that a 10 mm drill must be

selected from position number 10 of a tool magazine (holder).

h) Miscellaneous Functions (M-code): These are used to specify certain miscellaneous or

auxiliary functions (coolant on, coolant off, spindle on CW/CCW, spindle stop, etc)

available on the given machine.

NC LATHE

5

Z +Z –

Length

Dia

Face

(0,0)

X

Z

Chuck




1.6 Dimensional Notations used in CNC lathe are:

1. Absolute Dimensioning – X & Z are used.

2. Incremental Dimensioning – U & W are used.

PointABSOLUTE INCREMENTAL

X Z U W

P1 20 0 20 0

P2 20 -25 0 -25

P3 25 -25 5 0

P4 25 -55 0 -30

P5 30 -55 5 0

P6 30 -80 0 -25

Note: Incremental program is easy to program but tedious to change values in between. Error

committed in any block is carried over to the consecutive blocks. Whereas, absolute

programming is a bit inconvenient as all coordinates are measured from a fixed point. Error

committed in any block will affect only that block. Consecutive blocks are not affected.

6

P1P2

P3P4

P5P6

30

25

20

25 30 25




1.7 Zero points & Reference points on a CNC lathe:

Above figure shows the location and the relationship between Zero Points & Reference Point on

a CNC lathe.

1.8 Commonly used G-codes on the XLTURN machine:

G00 Positioning(Rapid Feed)

G01 Linear Interpolation(Cutting Feed)

G02 Circular Interpolation CW

G03 Circular Interpolation CCW

G04 Dwell

G17 XY Plane

G18 ZX Plane

G19 YZ Plane

G20 Inch Mode Input

G21 Metric Mode Input

G28 Return To Reference Point(Homing)

G70 Finishing Cycle

G71 Profile Turning Cycle

G72 Profile Facing Cycle

G74 Drilling Cycle

G75 Grooving Cycle

G76 Threading cycle

G90 Turning Cycle

G92 Treading Cycle

G94 Facing Cycle

(0,0)

X

Z

Max Z

Max

X

WM

R

M: Machine Zero Point W : Workpiece(Program) Zero Point

R: Reference point OR Home Position

7




G98 Feed per Minute

G99 Feed per Revolution

1.9 Commonly used M-codes on the XLTURN machine:

M00 Program Stop

M01 Optional Stop

M02 Program Reset

M03 Spindle Forward

M04 Spindle Reverse

M05 Spindle Stop

M06 Auto Tool Change

M08 Coolant ON

M09 Coolant OFF

M13 Spindle Forward and Coolant ON

M14 Spindle Reverse and Coolant ON

M98 Sub Program Call

M99 Sub Program Exit

M30 Program Reset and Rewind

G00 Rapid traverse

When the tool being positioned at a point preparatory to a cutting motion, to save time it is

moved along a straight line at Rapid traverse, at a fixed traverse rate which is pre-programmed

into the machine's control system. Typical rapid traverse rates are 10 to 25 m /min., but can be as

high as 80 m/min.

Format

N_ G00 X_ Z_

8




G01 Linear interpolation (feed traverse)

The tool moves along a straight line in one or two axis simultaneously at a programmed linear

speed, the feed rate.

Format

N__ G01 X__ Z__ F__

G02/03 Circular interpolation

Format

N__ G02/03 X__ Z__ I__ K__ F__ using the arc center

OR

N__ G02/03 X__ Z__ R__ F__ using the arc radius

G02 moves along a CW arc

G03 moves along a CCW arc

Arc center

The arc center is specified by addresses I and K. I and K are the X and Z co-ordinates of the arc

center with reference to the arc start point.

9




I =(X coord. of center - X coord. of start point)/2

K = Z coord. of center - Z coord. of start point

I and K must be written with their signs.

Arc radius

The radius is

Specified with address R.

G02 X__ Z__ R__ F__

N__ G03 X__ Z__ R__ F__

If the radius is used, only arcs of less than 180 deg. can be programmed in a block. An arc with

included angle greater than 180 deg. must be specified in two blocks.

1.10 Canned cycles

A canned cycle simplifies a program by using a few blocks containing G-codes functions to

specify the machining operations usually specified in several blocks

I. Turning Cycle - G71

Format

G71 U (d) R (e)

G71 P(n) Q(n) U(u) W(w) F(f)

N (n) _ _ _ _

_ _ _ _ _ _ _

_ _ _ _ _ _ _

N (n) _ _ _ _

d = Depth of cut

10




e = Retract amount

n = Number of the first block of the shape

n = Number of the last block of the shape

u = Finishing allowance in X

w =Finishing allowance in Z

f = Feed rate

II. Step Facing Cycle (G94 Cycle):

It is a ‘Box type’ cutting cycle.

SYNTAX:

G94 X… (U….) Z….. (W…..) F…..

Where,

X is the diameter to which the movement is being made OR U is the incremental distance from

the current tool position to the required final diameter.

Z is the Z axis coordinate to which the movement is being made OR W is the incremental

distance from the current tool position to the required Z axis position.

F is the feed rate.

TP-1. Write a program to perform the step facing of the component as shown in the figure:

O1001

([BILLET X30 Z70)

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X31 Z0

G94 X10 Z-0.5 F30

Z-1

Z-1.5

Z-2

Z-2.5

X20 Z-3

Z-3.5

11

F R

R

F

Tool Entry point

30

20

10

2.5 2.5




Z-4

Z-4.5

Z-5

G28 U0 W0

M05

M30

12




III. Step Turning Operation using the Box Turning Cycle (G90):

The Step Turning Operation can be performed by using the “Box Turning Cycle – G90 Cycle” as

below.

SYNTAX:

G90 X…..Z……F…….

Where,

X is the diameter to which movement is being made

Z is the Z axis coordinate to which the movement is being made

F is the feed rate being used

TP-2 Using the G90 Cycle; write a part program to step turn a work piece as shown below:

O1003

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X30 Z1

G90 X30 Z-55 F30

X29

X28

X27

X26

X25

G00 X25 Z1

G90 X25 Z-25 F30

X24

X23

X22

X21

X20

G28 U0 W0

13

Tool Entry point

30

25

20

30 25

F

R

R

F

Tool Entry

Point




M05

M30

14




IV. Taper Turning Cycle (G90 Cycle):

The above taper turning operation can be performed by the standard “G90 Taper Turning

Cycle”. Its syntax is:

G90 X….Z….R…..F…..

Where,

X is the diameter to which the movement is being made.

Z is the Z axis coordinate to which the movement is being made.

R is the difference in incremental of the cut start radius value and the cut finish radius value.

TP-3 Write a part program to perform the taper turning operation using the “G90 Taper Turning

Cycle (R –ve)” for the work part shown in figure.

O1004

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X30 Z1

G90 X30 Z-10 R0 F50 [(30-30)/2 = 0]

X30 R-0.5 [(29-30)/2 = -0.5]

X30 R-1 [(28-30)/2 = -1]

X30 R-1.5 [(27-30)/2 = -1.5]

X30 R-2 [(26-30)/2 = -2]

X30 R-2.5 [(25-30)/2 = -2.5]

G28 U0 W0

M05

M30

15

Tool Entry point

30

25

10




TP-4. Write a part program to perform the taper turning operation using the “G90 Taper Turning

Cycle (R +ve)” for the work part shown in figure.

O1005

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X30 Z1

G90 X30 Z-10 R0 F50 [(30-30)/2 = 0]

X29 R0.5 [(30-29)/2 = 0.5]

X28 R1 [(30-28)/2 = 1]

X27 R1.5 [(30-27)/2 = 1.5]

X26 R2 [(30-26)/2 = 2]

X25 R2.5 [(30-25)/2 = 2.5]

G28 U0 W0

M05

M30

V. Multiple Turning Cycle (G71 Cycle):

The Multiple Turning Cycle is used when the major direction of cut is along the Z axis. This

cycle causes the profile to be roughed out by turning. Two G71 blocks are needed to specify all

the values.

Syntax: G71 U……R……

G71 P…..Q……U…..W…..F……

VI. Finishing Cycle (G70 Cycle):

16

Tool Entry point

30

25

10

X29X28X27X26

X25

Tool Entry Point

Tool Entry Point

U is the depth of cut.R is the relief or retract amount

P is the block number of the start of the final profile

Q is the block number of the end of the final profile.

U is the finishing allowance for the X axisW is the finishing allowance for the Z axis

F is the feed rate




On completion of any roughing operation, the material left as finishing allowance is removed

using the ‘Finishing Cycle’. The same tool path used in the roughing operation is used in the

G70 cycle. The G70 Cycle causes a range of specified blocks to be executed, then control passes

on to the block after the G70 Cycle.

Syntax: G70 P….Q….F…..

Where, P is the block number of the start of the final profile

Q is the block number of the end of the final profile.

TP-5 Write a part program for Multiple Turning operation for the component shown in the

figure.

O1006

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X30 Z1

G71 U0.5 R1

G71 P1 Q10 U0.5 W0.5 F50

N1 G01 X7

N2 X9 Z-2

N3 Z-15

N4 G02 X14 Z-22 R8

N5 G01 X17 Z-27

N6 Z-32

N7 G03 X22 Z-39 R8

N8 G01 X24

N9 X28 Z-44

N10 X30

G70 P1 Q10 F50

POINT X Z

P1 7 0

P2 9 -2

P3 9 -15

P4 14 -22

P5 17 -27

P6 17 -32

P7 22 -39

P8 24 -39

P9 28 -44

P10 30 -4417

Tool Entry point

30 28

22

17

14

9

R 8

R 8

13 275575

24

P1P2P3

P4

P5P6

P7P8

P9

P10

7




G28 U0 W0

M05

M30

18





figure. Use a finishing tool for the finishing cycle.

O1007

[BILLET X30 Z70

G21 G98

G28 U0 W0

M06 T0101 (Select roughing tool)

M03 S1200

G00 X30 Z1 (Select Entry Point)

G71 U0.5 R1

G71 P10 Q20 U0.5 W0.5 F50

N10 G01 X8

X10 Z-2

Z-15

G03 X20 Z-25 R10

N20 G01 X30 Z-35

G28 U0 W0

M06 T0303

M03 S1450

G00 X30 Z1

G70 P10 Q20 F40

G28 U0 W0

M05

M30

Note: Whenever a tool change is to be made, current tool must be sent to ‘Home Position’ by

using the G28 command, so as to ensure that turret indexing will not interfere with workpiece or

machine tool parts (work table).

19

Select Finishing Tool

30

20

10 8

R 10

10 13 210





figure. Note that it is the same component as shown above except that there is an extra taper

before the circular interpolation.

It should be noted that the G71 cycle works only for continuously increasing (for external

operation) or decreasing (for internal operations) dimensions only. Hence the shaded portion in

the figure must be removed separately (by using the G90 R +ve cycle) after using the G71 cycle.

O1008

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X30 Z1

G71 U0.5 R1

G71 P10 Q20 U0.5 W0.5 F50

N10 G01 X8

X10 Z-2

Z-15

G03 X20 Z-25 R10

N20 G01 X30 Z-35

G00 X10 Z-2

G90 X10 Z-15 R0 F30

X9 R0.5

X8 R1

X7 R1.5

X6 R2

X5 R2.5

G28 U0 W0

M05

M30

20

Tool Entry point

G90 Cycle to machine the taper.




1.12 Subprogram:

A CNC program is divided into a main program & a subprogram. Normally the CNC operates

according to the main program but when a command calling a subprogram is encountered in the

main program, control is passed to the subprogram. When a command indicating a return to the

main program is encountered in the subprogram, control is returned to the main program. The

first block of the main program & sub program must contain a program number starting with

letter ‘O’.

Use of subprogram: When a program contains certain fixed sequences or frequently repeated

patterns, these sequences or patterns can be entered into the memory as a subprogram to simplify

programming. If a subprogram can call another subprogram, it is regarded as a one loop sub

program call.

Syntax: M98 P0000000

M99

21

Subprogram No.

No. of repetitions

Subprogram call

Command used in main program

Command used in Subprogram

O0001

……..

……..

M980012222

……..

……..

……..

M30

Main ProgramO2222

……..

……..

M980013333

……..

……..

……..

M99

O3333

……..

……..

……..

……..

……..

……..

M99

Subprogram Subprogram




Note: If the Number of repetition is omitted, the called subprogram is executed only once.

22




TP-8. Write a part program to machine the component shown in the figure making use of a sub

program.

O1009

[BILLET X22 Z70

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X22 Z1

G90 X22 Z-40 F50

X21

X20

G00 X20 Z0

M98 P0032000

G00 X20 Z-30

G90 X20 Z-40 F50

X19

X18

X17

X16

X15

G28 U0 W0

M05

M30

Note: (1) While writing the subprogram, incremental dimensioning is normally used.

Dimensions which remain constant in every pass can be programmed as absolute dimensions.

(2) Main program and sub-programs are written in separate files

Subprogram Nesting: When one subprogram calls for another subprogram, subprogram nesting

is said to be done.

23

22

15

20

10 5 5 5 5 5 5

Tool Entry point

O2000G90 X20 W-5 R0 F30

X20 R-0.5X20 R-1X20 R-1.5X20 R-2X20 R-2.5

G00 X20 W-5G90 X20 W-5 R0 F30

X19 R0.5X18 R1X17 R1.5X16 R2X15 R2.5

G00 X20 W-5M99




TP-9 Write a part program for the component shown in figure making use of the ‘Subprogram

Nesting’.

O1010

[BILLET X22 Z70

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X22 Z1

G90 X22 Z-60 F50

X21

X20

G00 X20 Z0

M98 P0012020

M98 P0012020

M98 P0012020

G28 U0 W0

M05

M30

O2020

G90 X20 W-5 R0 F30

X20 R-0.5

X20 R-1

X20 R-1.5

X20 R-2

X20 R-2.5

G00 X20 W-10

G90 X20 W-5 R0 F30

X19 R0.5

X18 R1

24

22

15

20

5 5 5 5 5 5 55 5 5 55

Tool Entry point

O2030

G90 X20 W-5 F50

X19

X18

X17

X16

X15

G00 X20 W-5

M99




X17 R1.5

X16 R2

X15 R2.5

G00 X20 W-5

M98 P0012030

M99

VII. External Grooving (G81 Cycle):

Syntax: G81 X….Z…..F…..

Where,

X is the diameter up to which the grooving must be done.

Z is the Z-axis coordinate where the grooving must be done.

F is the feed rate.

TP-10 Write a part program for performing the external grooving operation for the component

shown in figure.

O1011

[BILLET X22 Z70

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X22 Z1

G71 U0.5 R1

G71 P10 Q20 U0.5 W0.5 F40

N10 G01 X10

X12 Z-2

X12 Z-20

G02 X18 Z-27

G01 X18 Z-37

N20 X22 Z-45

25

Tool Entry point

3 mm

Note: The required grooves are 4 mm wide whereas the width of the tool tip is only 3mm. Hence, the sequence of G81 cycles are used twice, during the second set, tool is made to move by 1 mm so that the final groove width will be 4 mm.

22

18

10

R 7

8 27 510 13

12 10

15

4

5




G28 U0 W0

M06 T0303

M03 S800

G00 X12 Z-15

G81 X11.5 Z-15 F30

X11

X10.5

X10

26

Call grooving tool




G00 X13 Z-15

G81 X11.5 Z-14 F30

X11

X10.5

X10

G00 X19

Z-37

G81 X18.5 Z-37 F30

X18

X17.5

X17

X16.5

X16

X15.5

X15

G00 X19

Z-36

G81 X18.5 Z-36 F30

X18

X17.5

X17

X16.5

X16

X15.5

X15

G00 X19

G28 U0 W0

M05

M30

27



EngineeringCOMPUTER INTEGRATED MANUFACTURING: 06MEL77

VIII. External Threading: The threading operation can be performed by using the ‘Box

Threading Cycle-G92 Cycle’.

Syntax: G92 X…..Z…..F…..

Where, X is the diameter up to which the thread must be cut.

Z is the Z axis coordinate up to which the thread must be cut.

F is the pitch.

ISO Metric Thread Parameters:

For Metric Thread, (60o tool

angle), given the major diameter and pitch, the thread height can be given by:

h = (pitch) × 0.61343

Then the Core (Minor) Diameter can be given as:

Core Diameter = (Major diameter) – 2(h)

Commonly used thread parameters for ISO metric thread:

Major Diameter

(mm)

Pitch

(mm)

Major Diameter

(mm)

Pitch

(mm)

M 2.5 0.45 M 12 1.75

M 3 0.5 M 16 2

M 4 0.7 M 20 2.5

M 5 0.8 M 24 3

M 6 1 M 30 3.5

M 8 1.25 M 33 3.5

M 10 1.5 M 36 428




TP-11 Write a part program to perform the threading operation on the component as shown

in the figure.

O1012

[BILLET X22 Z70

G21 G98

G28 U0 W0

M06 T0101

M03 S1200

G00 X22 Z1

G71 U0.5 R1

G71 P10 Q20 U0.5 W0.5 F50

N10 G01 X8

X10 Z-2

Z-25

N20 X22 Z-35

G28 U0 W0

M06 T0303

M03 S800

M98P0022040

G28 U0 W0

M06 T0505

M03 S800

G00 X15 Z2

G92 X10 Z-23 F1.5

X9.75

X9.50

X9.25

X9.00

X8.75

X8.50

X8.25

X8.159

Tool Entry point

O2040

G81 X10 W0 F30

X9.5

X9

X8.5

X8

X7.5

X7

G00 X11

W1

M99

Calculation of Core dia:

Thread height = h = (pitch) × 0.61343

= 1.5 × 0.61343

= 0.920 mmCall grooving tool

Call threading tool

22

10 8 7

2510

4

M10 × 1.5

2

29




G28 U0 W0

M05

M30

Exercise Programs:

EXTRA CLASS

Internal Operation: The motion commands G00, G01, G02 & G03 as well as some of the

cycles G90 (Linear & Taper), G71, G81, etc. can be performed as internal operations also.

Pilot Hole Drilling (G74 Cycle): The Pilot hole required to perform any other internal

operations can be performed by using the G74 Cycle.

Syntax: G74 R……

G74 X…..Z…..Q…..F……

Where, R is the relief or retract amount

X is the diametral position of the hole

Z is length of the hole

Q is the peck increment (in microns, where, 1 mm = 1000 microns)

F is the feed rate

TP-12 Write a part program to perform the ‘Pilot Hole Drilling’ on the component as shown

in the figure.

O1013

[BILLET X30 Z70

G21 G98

G28 U0 W0

M06 T0505

M03 S1200

G00 X0 Z1

G74 R1

G74 X0 Z-8 Q500 F50

G28 U0 W0

M05

M30

Tool Entry point

Call 8 mm center drill

8

8

CENTER DRILL

8

8

30

30




TP-13 Write a part program to perform the internal step turning operation (internal boring)

on the component as shown in the figure.

O1014

[BILLET X30 Z70

G21 G98

G28 U0 W0

M06 T0505

M03 S1200

G00 X0 Z1

G74 R1

G74 X0 Z-8 Q500 F50

G28 U0 W0

M06 T0707

M03 S800

G00 X0 Z2

G74 R1

G74 X0 Z-75 Q500 F30

G28 U0 W0

M06 T0101

M03 S1200

G00 X12 Z2

G90 X12 Z-6 F50

X13

X14

X15

X16

X17 Z-40

X18

X19

X20

X21

12

30

16 22

28

16 20 20 20Tool Entry point



Call 10 mm boring bar

10

10 mm boring bar

31




X22

X23 Z-20

X24

X25

X26

X27

X28

G28 U0 W0

M05

M30

TP-14 Write a part program to perform the internal contouring operation on the component

as shown in the figure.

O1015

[BILLET X30 Z70

G21 G98

G28 U0 W0

M06 T0505

M03 S1200

G00 X0 Z1

G74 R1

G74 X0 Z-8 Q500 F50

G28 U0 W0

M06 T0707

M03 S800

1520 10 8 10 7 5

17

13

22

28

30

12

R 6

R 5

Tool Entry point



32




G00 X0 Z2

G74 R1

G74 X0 Z-75 Q500 F30

G28 U0 W0

M06 T0101

M03 S1200

G00 X12 Z2

G71 U0.5 R1

G71 P10 Q20 U0.2 W0 F50

N10 G01 X30

X28 Z-5

G02 X22 W-7 R5

X17

W-10

G03 X13 W-8 R6

G01 W-10

N20 G01 X12 W-15

G70 P10 Q20 F50

G28 U0 W0

M05

M30

Call 10 mm boring bar

10

10 mm boring bar

33




2. INTRODUCTION TO CNC MILLING, PROGRAMS ON MILLINGCNC MLL

In CNC Mill we have 3 axes – X axis (along length), Y axis (along breadth) & Z axis (along

thickness). The position of the Z axis is along the spindle axis and it is +ve in a direction

away from the workpiece. The position of the X & Y axis is parallel to and on the worktable.

X axis is along the length and Y axis is along the breadth of the table. X and Y axes are +ve

in directions moving away from the workpiece.

2.1 Automatic Tool Changer (ATC): It is a facility or device provided on the CNC Mill for

automatically indexing the tool magazine and making the required tool change as indicated in

the CNC program.

2.2 Automatic Pallet Changer (APC): It is a time saving facility provided on the CNC Mill

for automatically loading and unloading the pallets. Pallets are portable work holding

devices. While a loaded pallet is being used, a machined-component may be unloaded from

the pallet and a to-be-machined workpiece may be loaded on to the pallet.

2.3 Dimensional Notations used in CNC Mill are:

X Coordinate value along the length of the table

Y Coordinate value along the breadth of the table

Z Coordinate value along the vertical to the table

34




2.4 Programming Method - Absolute & Incremental Programming:

Absolute programming is specified by the G code G90 and incremental programming by

G91. In absolute programming, coordinate values are measured from the program zero point.

In incremental programming, the coordinate values are measured from the previous

programmed point

Point

ABSOLUTE (G90) INCREMENTAL

(G91)

X Y X Y

P1 0 0 0 0

P2 0 100 0 100

P3 60 100 60 0

P4 60 70 0 -30

P5 100 70 40 0

P6 100 30 0 -40

P7 20 30 -80 0

P8 20 0 0 -30

P1 0 0 -20 0

Note: Incremental program is easy to program but tedious to change values in between. Error

committed in any block is carried over to the consecutive blocks. Whereas, absolute

programming is a bit inconvenient as all coordinates are measured from a fixed point. Error

committed in any block will affect only that block. Consecutive blocks are not affected.

P1

P2

P3

P5

P6

P7

P8

60

40

3 04 0

3 0

20

80

P4

35




2.5 Commonly used G-codes on the FANUC Controller CNC Mill

G00

Rapid Traverse (Tool moves at a predetermined rapid speed

without making contact with the workpiece).

G01

Linear interpolation (Tool moves at a speed specified in the feed

word)

G20 Inches programming

G21 Metric programming

G28 Return to reference point OR home position

G02 Circular Interpolation CW

G03 Circular Interpolation CCW

G90 Absolute Programming

G91 Incremental Programming

G94 Feed programmed in mm/min

G95 Feed programmed in mm/rev

2.6 Commonly used M-codes on the FANUC Controller CNC Mill

M01 Optional stop

M02 Program end

M03 Spindle ON CW

M04 Spindle ON CCW

M05 Spindle OFF

M06 Tool change

M08 Coolant ON

M09 Coolant OFF

M30 Program stop & rewind

M70 X Mirror ON

M71 Y Mirror ON

M80 X Mirror OFF

M81 Y Mirror OFF

M98 Subprogram Call

M99 Subprogram end

36




2.7 Subprogram:

A CNC program is divided into a main program & a subprogram. Normally the CNC

operates according to the main program but when a command calling a subprogram is

encountered in the main program, control is passed to the subprogram. When a command

indicating a return to the main program is encountered in the subprogram, control is returned

to the main program. The first block of the main program & sub program must contain a

program number starting with letter ‘O’.

Use of subprogram: When a program contains certain fixed sequences or frequently

repeated patterns, these sequences or patterns can be entered into the memory as a

subprogram to simplify programming. If a subprogram can call another subprogram, it is

regarded as a one loop sub program call.

Syntax: M98 P0000000

M99

Subprogram No.

No. of repetitions

Subprogram call

Command used in main program

Command used in Subprogram

O0001

……..

……..

M980012222

……..

……..

……..

M30

Main ProgramO2222

……..

……..

M980013333

……..

……..

……..

M99

O3333

……..

……..

……..

……..

……..

……..

M99

SubProgram SubProgram

37




MP 1. Write a part program to perform the contour slotting operation on the component as

shown in the figure. The slot should have a width of 8 mm and a depth of 1 mm.

O0003

([BILLET X100 Y100 Z10)

([TOOLDEF T01 D8)

([EDGEMOVE X0 Y0)

G21 G94

G91 G28 Z0

G28 X0 Y0

G90

M06 T01

M03 S1200

G00 X20 Y10 Z5

G01 Z-1 F50 (P1)

G03 X10 Y20 R10 (P2)

G01 X10 Y80 (P3)

X20 Y90 (P4)

X80 Y90 (P5)

G02 X90 Y80 R10 (P6)

G01 X90 Y10 (P7)

X20 Y10 (P1)

G00 Z5

G91 G28 Z0

G28 X0 Y0

G90

M05

M30

X Y

P1 20 10

P2 10 20

P3 10 80

P4 20 90

P5 80 90

P6 90 80

P7 90 10

P1 20 10

70

20

80 060 010

20

P1

P2

P3

P4 P5

P7

P6

10 60

10

10

R 10

R 10

Billet Size 100 x 100 x 10 mm

Cutter Dia: 8 mm

38




MP 2. Write a part program to perform the contour slotting operation on the component as

shown in the figure for program MP 1. The slot should have a width of 8 mm and a depth of 5

mm. Use subprogram with a maximum depth of cut of 1 mm per pass.

O0004

G21 G94

G91 G28 Z0

G28 X0 Y0

G90

M06 T01

M03 S1200

G00 X20 Y10 Z5

G01 Z0 F30

M98 P0051155

G01 Z5

G91 G28 Z0

G28 X0 Y0

G90

M05

M30

O1155

G91 G01 Z-1 F40 (P1)

G90

G03 X10 Y20 R10 (P2)

G01 X10 Y80 (P3)

X20 Y90 (P4)

X80 Y90 (P5)

G02 X90 Y80 R10 (P6)

G01 X90 Y10 (P7)

X20 Y10 (P1)

M99

39




2.8 Slab Milling

MP 3. Write a part program to perform the square slab milling operation on a workpiece of

dimensions 100mm100mm10 mm. The slab’s dimension is 64mm64mm6mm and is

located at the centre of the workpiece. Use a cutter diameter of 10 mm. Take program zero at

the left bottom end of the workpiece.

O1122

G21 G94

G91 G28 Z0

G28 X0 Y0

G90

M06 T01

M03 S1000

G00 X0 Y0 Z5

G01 Z0 F30

M98 P0063456

G01 Z5

G91 G28 Z0

G28 X0 Y0

G90

M05 M30

O3456

G91 G01 Z-1 F30

G90

G01 X100 Y0

X100 Y100

X0 Y100

X0 Y0

X5 Y5

X95 Y5

X95 Y95

X5 Y95

X5 Y5

X10 Y10

X90 Y10

X90 Y90

X10 Y90

X10 Y10

G42 G01 X18 Y18

X82 Y18

X82 Y82

X18 Y82

X18 Y18

X50 Y18

64 mm

64 m

m

100

mm

10 m

m6 mm

100 mm

40




X50 Y10

G40

G01 X0 Y0

M99

2.9 Circular Pocket Milling

MP 4.Write a part program to perform the Circular Pocket Milling operation on a workpiece

of dimensions 100mm100mm10 mm. The pocket’s dimension is R376mm depth and is

located at the centre of the workpiece. Use a cutter diameter of 10 mm. Take program zero at

the top face center of the workpiece.

O1123

G21 G94

G91 G28 Z0

G28 X0 Y0

G90

M06 T01

M03 S1000

G00 X0 Y0 Z5

G01 Z0 F30

M98 P0065973

G01 Z5

G91 G28 Z0

G28 X0 Y0

G90

M05

M30

O5973

G91 G01 Z-1 F30

G90

G01 X5 Y0

G03 X-5 Y0 R5

X5 Y0 R5

G01 X10 Y0

G03 X-10 Y0 R10

X10 Y0 R10

G01 X15 Y0

G03 X-15 Y0 R15

X15 Y0 R15G01 X20 Y0

G03 X-20 Y0 R20

X20 Y0 R20

G01 X25 Y0

G03 X-25 Y0 R25

X25 Y0 R25

G01 X30 Y0

G03 X-30 Y0 R30

X30 Y0 R30 41




G41 G01 X37 Y0

G03 X-37 Y0 R37

X37 Y0 R37

X0 Y37 R37

G01 X0 Y25

G40

G01 X0 Y0

M99

2.10 Square Pocket Milling

MP 5.Write a part program to perform the Square Pocket Milling operation on a workpiece

of dimensions 100mm100mm10 mm. The pocket’s dimension is 57mm57mm8mm

and is located at the centre of the workpiece. Use a cutter diameter of 10 mm. Take program

zero at the top face center of the workpiece.

O1124

G21 G94

G91 G28 Z0

G28 X0 Y0

G90

M06 T01

M03 S1000

G00 X0 Y0 Z5

G01 Z0 F30

M98 P0087061

G01 Z5

G91 G28 Z0

G28 X0 Y0

G90

M05

M30

O7061

G91 G01 Z-1 F30

G90

G01 X5 Y0

X5 Y5

X-5 Y5

X-5 Y-5

X5 Y-5

X5 Y0

X10 Y0

X10 Y10

X-10 Y10

X-10 Y-10

X10 Y-10

X10 Y0

X15 Y0

100mm

57 mm

57 m

m

100

mm

8 mm

10 mm

42




X15 Y15

X-15 Y15

X-15 Y-15

X15 Y-15

X15 Y0

G41 G01 X21.5 Y0

X21.5 Y21.5

X-21.5 Y21.5

X-21.5 Y-21.5

X21.5 Y-21.5

X21.5 Y10

X15 Y10

G40

G01 X0 Y0

M99

2.11 Rectangular Pocket Milling

MP 6.Write a part program to perform the Rectangular Pocket Milling operation on a

workpiece of dimensions 100mm100mm10 mm. The pocket’s dimension is

73mm61mm5mm and is located at the centre of the workpiece. Use a cutter diameter of

10 mm. Length of the pocket is parallel to X axis. Take program zero at the top face center of

the workpiece.

O9128

G21 G94

G91 G28 Z0

G28 X0 Y0

G90

M06 T01

M03 S1000

G00 X0 Y0 Z5

G01 Z0 F30

M98 P0058753

G01 Z5

G91 G28 Z0

G28 X0 Y0

G90

M05

M30

O8753

G91 G01 Z-1 F30

Y/X = Breadth / Length =61/73 = 0.8356

Y = (0.8356) X

X (mm) Y (mm)5 4.1781

10 8.356115 12.534220 16.712325 20.890430 25.0685

36.5 30.5

73 mm

100 mm

100

mm

61 m

m

5 mm

10 mm

43




G90

G01 X5 Y0

X5 Y4.1781

X-5 Y4.1781

X-5 Y-4.1781

X5 Y-4.1781

X5 Y0

X10 Y0

X10 Y8.3561

X-10 Y8.3561

X-10 Y-8.3561

X10 Y-8.3561

X10 Y0

X15 Y0

X15 Y12.5342

X-15 Y12.5342

X-15 Y-12.5342

X15 Y-12.5342

X15 Y0

X20 Y0

X20 Y16.7123

X-20 Y16.7123

X-20 Y-16.7123

X20 Y-16.7123

X20 Y0

X25 Y0

X25 Y20.8904

X-25 Y20.8904

X-25 Y-20.8904

X25 Y-20.8904

X25 Y0

X30 Y0

X30 Y25.0685

X-30 Y25.0685

X-30 Y-25.0685

X30 Y-25.0685

X30 Y0

G41 G01 X36.5 Y0

X36.5 Y30.5

X-36.5 Y30.5

X-36.5 Y-30.5

X36.5 Y-30.5

X36.5 Y10

X25 Y10

G40

G01 X0 Y0

M99

44




2.12 Mirroring: If symmetrical contours (symmetry about X axis only, symmetry about Y

axis only OR simultaneous symmetry about both X & Y axes) are to be machined on a

component, the mirroring feature in CNC programming can be selected to ease the task of

programming. Here, part program (usually a sub-program) is written only for one of the

contours of the symmetric pair. Part program for the other part of the pair can be appended by

just selecting the ‘Mirror On’ feature.

M codes that are used for selecting the ‘Mirror On’ feature are:

M70 X Mirror ON means all future X coordinates programmed

are taken with –ve values.

M71 Y Mirror ON means all future Y coordinates programmed

are taken with –ve values.

M80 X Mirror OFF to cancle X Mirroring

M81 Y Mirror OFF to cancle Y Mirroring

Note: (1) Simultaneous mirroring of X & Y values is possible by programming both M70 &

M71.

(2) Mirroring changes the CW arc tool movement to CCW and vice-versa. In other

words, G02 becomes G03 and G03 becomes G02

45




MP 7.Write a part program to perform the mirroring operation on the component as shown in

the figure. Take cutter dia = 8 mm. Let the depth of the slot be 1 mm.

O0006

G21 G94

G91 G28 Z0

G28 X0 Y0

G90

M06 T02

M03 S1200

G00 X0 Y0 Z5

M98 P0017577

M70 X Mirror ON

M98 P0017577

M80 X Mirror OFF

M71 Y Mirror ON

M98 P0017577

M70 X Mirror ON

M98 P0017577

M80 X Mirror OFF

M81 Y Mirror ON

G91 G28 Z0

G28 X0 Y0

M05 M30

30

30

10

10

50

5010

10

Billet Size: 100 x 100 x 10 mm

O7577

G00 X10 Y10

G01 Z-1 F50

X10 Y40

X40 Y10

X10 Y10

Z5

G00 X0 Y0

M99

46




3. CAPSTURN AND CAPSMILL

3.1 CAPS Mill EXERCISE:

Sequence

numberOperations Tool

1 Facing 50 mm dia face mill

2 Contour pocketing 20 mm dia end mill

3 Rectangular pocketing 20 mm dia end mill

4 Drilling 9.8 mm dia twist drill

5 Counter Sinking 5-20 mm Counter sink 120o

6 Tapping M10 1.5 pitch

M10

1

.5 p

itch,

6 h

oles

on

60

PCD,

60o p

itch,

30

mm

dee

p

All dimensions in mm

47




3.2 CAPSTurn EXERCISE:

Sequence

numberOperations Tool

1 Plain Facing External facing tool

2 Contour turning External turning tool

3 Finish turning External finishing tool

4 Finish Facing External facing tool

5 Pilot hole drilling 8 mm dia center drill

6 Peck drilling 8.5 mm dia twist drill

All dimensions in mm

48




4. SIMULATION OF HYDRAULIC AND PNEUMATIC CIRCUITS

USING LMS IMAGE LAB (AMESIM) SOFTWARE.

49




50




5. Exercise Problems

51




52




6. DEFINITIONS OF FMS AND ASRS6.1 Flexible Manufacturing System (FMS)

An FMS can be defined as an integrated computer controlled configuration of NC machine

tools, other auxiliary production equipments, and a material handling system designed to

simultaneously manufacture low to medium volumes of a wide variety of high quality

products at low cost. An FMS is capable of processing a variety of different part styles

simultaneously at various workstations, the mix of part styles and quantities of production

can be adjusted in response to changing demand patterns. FMS is the most automated and

technologically sophisticated Group Technology cell. FMS is designed to produce parts (or

products) within a defined range of styles, sizes and processes. A typical FMS is shown in the

below illustration.

MC1- Machining center 1

MC2- Machining center 2

53

6.2 Automatic storage and Retrieval system

An automated storage and retrieval system (ASRS) can be defined as a storage system that

performs storage and retrieval operations with speed and accuracy under a defined degree of

automation. The performance of any manufacturing industry depends mostly on its material

handling and storage system. Generally, ASRS refers to a variety of computer-controlled

methods for automatically depositing and retrieving loads to and from defined storage

locations. Within an automated storage system environment, there are having several layouts

such as horizontal carousels, rotary carousels ,vertical carousels, vertical lift modules, and

fixed aisle storage and retrieval systems. A typical rotary carousels ASRS is show below.

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