SUBMITTEDBY:

ASHISH ACHARJEE

REG NO:-11102075

CENTRAL INSTITUTE OF HAND TOOL

• CIHT is an autonomous organization.

• CIHT is a National Institute.

• CIHT was established in 1983 with assistance from UNDP,

Government of India and Government of Punjab.

• CIHT is aspiring for latest technology to be a leader in

region.

SERVICE OFFERED AT CIHT

• Consultancy.

• Tool Room Services.

• Heat Treatment Shop.

• Forge Shop.

•Testing and quality control.

•Training services.

ADDRESS OF THE COMPANY:-Central Institute of Hand Tools

Maqsudan, Opp. ShaheedBhagat Singh Colony, G.T. Road, Bye Pass, Jalandhar City -

144 008,

State - Punjab, India.

Phone: +91.181.2290196

E-mail: institute_jld@dataone.in

COMPUTER NUMERICAL CONTROL (CNC) MACHINES

CNC is a microprocessor based control system that accepts a set of

program instructions, processes and sends output control

information to a machine tool, accepts feedback information

acquired from a transducer placed on the machine tool and based

on the instructions and feedback, assures that proper motion, speed

and operation occur.

A CNC system basically consists of the following:

(a) Central processing unit (CPU) (b) Servo control unit (c) Operator control panel (d) Machine control panel (e) Programmable logic controller

(f) Other peripheral devices

CNC LATHE MACHINE

Basic CNC Principles Coordinates System

TYPES OF CNC MACHINE

•Lathes for metal and plastics

Used to produce 3D product shapes and moulds for

plastic products.

•Milling machine for mould making and surface milling.

Used to produce dies for

die cutting printed products

•Drilling machine used in making drill in surface.

•Boring machine to increase the diameter of the hole.

•Grinding machine to obtain better surface texture.

CNC LATHE

•Automated version of a manual lathe.Programmed to change tools automatically.

•Used for turning and boring wood, metal and plastics.

HOW CNC WORKS

•Controlled by G and M codes.

•These are number values and co-ordinates.

•Each number or code is assigned to a particular

operation.

•Typed in manually to CAD by machine operators.

•G&M codes are automatically generated by the

computer software

FEATURES OF CNCMACHINERY

•The tool or material moves.

•Tools can operate in 1-5 axes.

•Larger machines have a machine control unit (MCU)

which manages operations.

•Movement is controlled by a motors (actuators).

Feedback is provided by sensors (transducers)

•Tool magazines are used to change tools automatically.

•Most are made from

high speed steel (HSS),

tungsten carbide or ceramics.

•Tools are designed to direct waste away from the

material.

•Some tools need coolant such as oil to protect the

tool and work.

TOOL

CNC PROGRAMMING BASICS

•CNC instructions are called part program commands.

•When running, a part program is interpreted one

command line at a time until all lines are completed.

•Commands, which are also referred to as blocks, are

made up of words which each begin with a letter address

and end with a numerical value.

•Each letter address relates to a specific machine

function. “G” and “M” letter addresses are two of the

most common. A “G” letter specifies certain machine

preparations such as inch or metric modes, or

absolutes versus incremental modes.

•A “M” letter specifies miscellaneous machine

functions and work like on/off switches for coolant

flow, tool changing, or spindle rotation. Other letter

addresses are used to direct a wide variety of other

machine commands.

OPERATING CONTROLLER OF CNC

1. SIMEN CONTROLLER

2. FANUC CONTROLLER

IMPORTANT THINGS TO KNOW

• Coordinate System

• Units, incremental or absolute positioning

• Coordinates: X,Y,Z, RX,RY,RZ

• Feed rate and spindle speed

• Coolant Control: On/Off, Flood, Mist

• Tool Control: Tool and tool parameters

CNC PROGRAMMING

•Programming consists of a series of instructions in form of letter codes.

•Preparatory Codes:

G codes- Initial machining setup and establishing operating conditions

•N codes- specify program line number to executed by the MCU

•Axis Codes: X,Y,Z - Used to specify motion of the slide along X, Y, Z

direction

•Feed and Speed Codes: F and S- Specify feed and spindle speed

•Tool codes: T – specify tool number

•Miscellaneous codes – M codes For coolant control and other activities

O - Program number (Used for program identification)

N - Sequence number (Used for line identification)

G - Preparatory function

X - X axis designation

Y - Y axis designation

Z - Z axis designation

R - Radius designation

F – Feed rate designation

S - Spindle speed designation

H - Tool length offset designation

D - Tool radius offset designation

T - Tool Designation

M - Miscellaneous function

EXPLANATION OF COMMONLY USED G CODES

• G00 – Preparatory code to control final position of the tool and not

concerned with the path that is followed in arriving at the final

destination.

• G01 – Tool is required to move in a straight line connecting

current position and final position. Used for tool movement

without any machining- point to point control. (linear

interpolation)

• G02 – Tool path followed is along an arc specified by I, J and K

codes.( circular interpolation)

IMPORTANT G CODES

G00 Rapid Transverse

G01 Linear Interpolation

G02 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 cancel

G41 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 cancel

G80 Cancel canned cycles

G81 Drilling cycle

G82 Counter boring cycle

G83 Deep hole drilling cycle

G90 Absolute positioning

G91 Incremental positioning

IMPORTANT MCODES

M00 Program stop

M01 Optional program stop

M02 Program end

M03 Spindle on clockwise

M04 Spindle on counterclockwise

M05 Spindle stop

M06 Tool change

M08 Coolant on

M09 Coolant off

M10 Clamps on

M11 Clamps off

M30 Program stop, reset to start

RULES FOE PROGRAMMING

• Restrictions on CNC blocks

• Each may contain only one tool move

• Each may contain any number of non-tool move G-

codes

• Each may contain only one feed rate

• Each may contain only one specified tool or spindle

speed

• The block numbers should be sequential.

• Both the program start flag and the program number

must be independent of all other commands (on separate

lines)

• The data within a block should follow the sequence.

45

36

FACING

G95G90G71G54

G96S500M03LMS=700F0.2

G00X92.0Z0.0

Z-1.0

G01X-1.5

X92.0Z-1.0

G00Z-2.0

G01X-1.5

G00X92.0Z-2.0

G00Z-3.0

G01X-1.5

G00X92.0Z-3.0

G00Z-4.0

G01X-1.5

G0X0Z0D0

M05

M09

M30

90

TURNING

100

7580

G95G90G71G54

G96S500M03LIMS=700F0.2

X79.0

G01Z-100.0

G00X79.0Z0.0

X78.0

G01Z-100.0

G00X77.0Z0.0

X76.0

G01Z-100.0

G00X77.0Z0.0

X75.0

G00X75.Z0.0

G00X80.0Z10.0

G0X0Z0D0

M05

M09

M30

5

10

5

STEP TURNING

ɸ75

ɸ80

ɸ70ɸ82

G95G90G71G54

G96S500M03LIMS=700F0.2

T1D1M06

G0X84.0Z0.0

X81.0

G01Z-30.0

G0X81.0Z0.0

X80.0

G01Z-30.0

G0X79.0Z0.0

G01Z-15.0

G0X79.0Z0.0

X78.0

G01Z-15.0

G0X78.0Z0.0

X76.0

G01X76.0Z0.0

X75.0

G01Z-15.0

G0X75.0Z0.0

X73.0

G01Z-5.0

G0X73.0Z0.0

X70.0

G01Z-15.0

G0X72.0Z10.0

GOXOZODO

M05

M09

M30

TAPER TURNING

ɸ75 ɸ70

G95G90G71G54

G96S500M03LIMS=700F0.2

T1D1M06

G00X76.0Z0.0

X74.0

G01X75.0Z-30.0

30

G00X76.0Z0.0

X72.0

G01X75.0Z-30.0

G00X76.0Z0.0

X71.0

G01X75.0Z-30.0

G00X76.0Z0.0

X70.0

G01X75.0Z-30.0

G00X76.0Z10.0

GOXOZODO

M05

M09

M30

GROOVING

60

5

30 30

ɸ60

G95G90G71G54

G96S500M03LIMS=700F0.2

T1D1M06

G00X62.0Z0.0

Z-30.0

G01X59.0

G00X62.0

G01X58.0

G00X62.0

G0157.0

G00X62.0

G01X56.0

G00X62.0

G0155.0

G00X62.0

Z10.0

G0X0Z0D0

M05

M09

M30

ADVANTAGES(a) High Repeatability and Precision, e.g. Aircraft parts.

(b) Volume of production is very high.

(c) Complex contours/surfaces need to be machined, e.g. Turbines.

(d) Flexibility in job change, automatic tool settings, less scrap.

(e) Safer, higher productivity, better quality.

(f) Less paper work, faster prototype production, reduction in lead

times.

(g) Easier to program.

(h) Easy storage of existing programs.

(i) Avoids human errors.

(j) Usually generates closer tolerances than manual machines.

(k) Program editing at the machine tool.

(l) Control systems upgrades possible.

(m) Option -resident CAM system at machine tool.

(n) Tool path verification

DISADVANTAGES

(a) Costly setup, skilled operators.

(b) Computers, programming knowledge required.

(c) Maintenance is difficult.

(d) Machines have to be installed in air conditioned places