Cnc

Presenter

Sunil SKS

Why CNC?

Milling Lathe

Why CNC?

Competition between manufacturing firms is increasingly dictated by

quality, cost, variety and Servicing.

Achieving the highest possible efficiency in manufacturing can only

produce each one of these attributes of a successful product.

Why CNC?

For the parts having complex contours, that cannot be manufactured by

conventional machine tools.

For small lot production, often for even single (one off) job production,

such as for prototyping, tool manufacturing, etc.

For jobs requiring very high accuracy and repeatability.

Why CNC?

For jobs requiring many set ups and/or the set ups are very expensive.

The inspection cost is a significant portion of the total manufacturing

cost.

Why CNC?

For the parts having complex contours, that cannot be

manufactured by conventional machine tools.

Why CNC?

For jobs requiring very high accuracy and repeatability.

Why CNC?

For jobs requiring many set ups and/or the set ups are very

expensive.

Why CNC?

The inspection cost is a significant portion of the total

manufacturing cost.

Why CNC?

What is CNC?

NUMERICAL CONTROL is a method of automatically operating a

manufacturing machine based on a code of letters, numbers, and special

characters.

What is CNC?

The program is translated into the appropriate electrical signals for

input to motors that run the machine.

CNC stands for Computer Numerical Control.

It is the technology of controlling a machining operation using a computer program, which is called Numerical Control (NC) Program.

In other words, a computer rather than a person will directly control the machine tool.

Conventional CNC

The most important computerized machine tools that are used extensively in the industry are:

CNC Turning (Lathe) machine

CNC Milling machine

Increased speed at which parts are produced (mass production).

Producing the same quality for all work parts.

Better dimensional accuracy which gives exact and correct dimensions.

Less scrap.

High initial cost

Need high qualified operator.

Basically there are two common

coordinate systems:

Cartesian coordinate

system

Polar coordinate

system

When dealing with 2 dimensions (2D), the two-dimensional coordinate system is used; Figure below

When dealing with three dimensions (3D), the three dimensional coordinate system is

used; see the Figure below

The angle is positive if it is measured in counterclockwise direction starting from positive X-axis; Fig. 1.5-A.

Locate points P1 through P4 on the

coordinate system shown in Fig. 1.4

P1 X = 80 Y = 60

P2 X = -80 Y = 20

P3 X = -50 Y = -60

P4 X = 60 Y = -70

How can you describe the line given in the figure using polar coordinate system?

Universal style slant bed turning center

Front view of machine

Headstock & Spindle


Work-holding Device


Tailstock

BodyQuill

Center



Turret

Z Axis- +



Z Axis- +

Z is the length controlling axis

X A

xis

-

+


X A

xis

-

+


X is the diameter controlling axis

X A

xis

-

+

3.000

X3.0


X is DIAMETERIf you want to turn a 3.0 inch diameter…

X3.0 will be the commanding word

X A

xis

-

+

3.000

X3.0

X is DIAMETER

Once again:X is always the diameter-controlling axisZ is always the length controlling axis

Also:X+: always gets bigger in diameterZ+: always away from the spindle

Though some machine tool builders reverse the polarity of the X axis

F 25

F 22.5

F 17.5

20

Raw Material

Finished Part

70

30

EXAMPLE:

O2456;

N10 G17 G21 G40 G90 ;

N20 M06 T01;

N30 M03 S2000;

……………………..

……………………..

……………………..

PROGRAM NUMBER

BLOCK

WORD

SEQUENCE NUMBER OR BLOCK IDENTIFICATION NUMBER

N10

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Cnc

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