part programming (cnc)

MANUFACTURING
The process in which we can produce a
geometrical shape from a raw material is
known as manufacturing.
It is the last stage of production.

PRODUCTION
The entire process to manufacture
a component is known as production.
VARIABLES AFFECTING
MANUFACTURING
* Man
*Machine
*Material

Machine
The device which is used to convert an
effort to an useful work is known as
machine.

Machine tool
It has the ability to produce it’s own
parts as well as other parts.

Machining Center
It can perform no of operation at a
time with the help of ATC & AWC
ATC-Automatic Tool Changer
AWC-Automatic Work Changer
According to tool holding capacity &
magazine shape ATC is up 3 types
Drum type(40 tools)
Elliptical type(8-20 tools)
Loop chain type(200 tools)

Machining center type
Vertical machining center

Spindle in vertical
position

Horizontal machining center

Spindle in horizontal position

Conventional Machining Process
 The machining process where the tool
is directly contact with the job is
known as conventional machining.
 In this machining the tool must be
harder than the job.
 Ex-cnc milling, cnc turning, grinding
milling, turning, etc

Non Conventional Machining Process
 The machining process where the tool is
not directly in contact with the job is
known as Non conventional machining.
 Here the tool can be softer than the
job.
 ExECM
EBM
AJM
EDM
Wire EDM

Cutting Speed
 The speed at which the cutting
edges of the tool travels over the
job is known as cutting speed.
 C.S = ∏*D*N/1000
where D =Diameter of the cutter
N =RPM of the machine
 Unit = m/min

Feed

 The advancement of the tool towards the
job is known as feed. Unit- mm
 When feed is compared with time it is
known as feed rate. Unit- mm/min
 The advancement between consecutive
tooth of cutter is known as feed per tooth.
Unit- mm/tooth
 The advancement of tool in one revolution
is known as feed per revolution.
Unit- mm/rev

Types of Feed rate
Rapid Feed rate-The idle movement of
the tool with max. available federate
of the m/c is known as Rapid feed.
Plunge Feed rate-The feed rate at the
time of taking depth of cut.
Cutting Feed rate-The feed rate at
the time of cutting operation.
Feed rate = F*Z*N
F = feed/tooth
Z = No of flutes or teeth
N = RPM of the machine

CNC-Computer Numerical Control
Need For CNC- A machine tool has several
controllable function i.e
- Speed
- Feed
- Tool positioning
- Clamping the work piece
- Coolant flow etc…
All these can be done either manually or
Automatically, for automatic control
several technologies are adopted
and CNC
is the latest among them.

CNC Advantages-

-Difficult contours & surfaces are easily
made.
-Closer geometrical & dimensional tolerances
are possible.
-Higher rate of production.
-Very low lead time.
-One m/c can perform several operation.
-Rejection is almost nil.
-No dependence over human operational.
skill.
-Dimensional variation can be
correctable very easily.
-Reduces inspection cost.
-Reduces tooling cost.

Disadvantages-

 Higher initial cost.
 Maintenance is expensive.
 May need A.C & voltage stabilizer.
 Productivity depends on the
programmer.
Classification of NC System-

 According to no of axis-2 axis m/c
-3axis m/c
-4axis m/c
-5 axis m/c

Five Axis machines
Table rotates round two simultaneous continuous axes
Designed for five axis precision machining of workpieces having
small dimensions and a complex geometry.
C-axis

A-axis

z

y
x

Location of Rotary axes on compound NC Tilt Round Table

According to Tool position-Absolute System
-Incremental system
 According to Feed back Device-Analog Type
-Digital type
 According to Servo control System-Open Loop
-Closed Loop

According to Motion control system-Point to point control
-Straight cut
-Contouring

Part Program-The set of instruction by
which we can produce a part is known as
part program.
It has 2 parts
-Main Block
-Sub Block

Main Program-

 It contains machine definition,
tool definition & raw material definition.
 It doesn’t deals with tool movement.

Sub Program-

 It only contains of tool movement.

DNC-Direct Numerical Control

When a program is generated in computer &
send to a single m/c ,then it is known as direct numerical
control.

DNC-Distributed Numerical Control

If the program is send to a no of m/c for mass
production is known as distributed numerical control.
*The cables used for DNC in CTTC are RS-232
& RS-422.

Transducer (Feedback device)
Transducer is of two types
1.Analog type
2.digital type
Analog transducer is a feed back device which

produces a variable electrical voltage. This
voltage varies in proportion to the rotational
speed of the input shaft and can be easily
measured and converted into linear distances to
indicate corresponding positions of m/c table.

Digital transducer : It is normally

employed to convert the rotary
motion of the machine lead screws
into countable electrical pulses. The
number of these pulses indicates the
linear distance moved by the table of
the m/c corresponding to the
rotation of the lead screws obviously,
this device must be attached to the
lead screw of the m/c table

Controller-

The soft ware which controls the program
in different languages is known as
controller.
Ex- *FANUC
*HEIDEN HEIN
*SINUMERIC
*LAXMI NUMERIC(Indian Controller)
*MAZATROL
*MAZAC

Codes-ISO
-Dialog Mode
-In ISO mode we have to write the
program with G-code & M-code.
Ex-G99 T1 L0 R5
-In Dialog mode we have to write the
program in English language.
Ex-Tooldef T L R

Program VariablesG- is known as Preparatory code
M-is known as Miscellaneous or machine
code
N- is known as Block no
S- is known as Spindle speed
F- is known as Feed rate
R- is known as Radius compensation
L- is known as Length offset
T- is known as Tool no

Steps to write a program-

* Read the drawing.
*Think about all sequential operation.
*Specify raw material size.
*Tool definition.
*Tool call.
*Specify the tool position.
*Specify the Z0 position.
*Specify the depth of cut.
*Specify co-ordinates for cutting operation.
*Retract the tool at the end of the cut.
-End of program.

G-code

G00-Rapid movement of the tool.
G01-Linear interpolation with control feed
rate.
G17-Tool orientation in XY plane in Z axis.
G18-Tool orientation in ZX plane in Y axis.
G19-Tool orientation in YZ plane in X axis.
G71-Metric programming mode.
G70-Inch programming mode.
G30-Lower left corner of the job.
G31-Upper right corner of the job.

G90-Absolute programming mode.
G91-Incrimental programming mode.

M-code

M00-Program stop.
M01-Optional stop.
M02-Program end
M30-Program end & reset
M03-Spindle orientation clock wise.
M04-Spindle orientation anti clock wise.
M08-Coolant on.
M09-Coolant `

M13-Spindle orientation clock wise
with coolant on.(M03+M08)
M14-Spindle orientation anti clock wise
with coolant on.(M04+M08)
M05-Spindle stop.
M06-Toolcall or Tool change.
Maximum movement of toolX-290
Y-170 Max.Lines & columns in CNC editor
Z-235

Lines-32647
Columns-241

Functional keysF1-Help
F2-For save
F3-For load or open
F5-Machine information
F7-To mark a block
F8(2 times)-To cancel a mark
F9-For simulation
F10-Main menu

*To run a programF9 Run program enter
*Datum setting-The process of defining the origin
of the w/p to the m/c is known as datum setting.
*To set the datumF9 set datum enter Use the navigation
Keys to set the values in x & y enter
*To save the fileF2 Define the file name(max.-8 character) enter
*To create new fileF10 cnc files enter new enter
*To open a fileF3
enter
Select the file enter

*To save as the fileF10 cnc files enter save as enter file name
enter
*To minimize the gap between the blockPlace the curser in the Gap Ctrl + Y
*To close the soft wareAlt + Q
*To delete the blockF7 Use down & up navigation keys to define the
block to delete Alt + D Y
*To copy the blockF7 Use navigation keys to define the
block to copy F8 move the curser to
the desired place Alt + C Y

*To move the blockSame as copy but use Alt + M
*To change the simulation typeF10 Settings enter Simulation
enter
Show 3D enter (To change from yes yes to no
Or no to yes) F9 run program enter

OFFSETThe value which is given to compensate the
structure of the tool is known as offset.
It is up 3types* Length Offset
* Diameter Offset
* Wear Offset

Length OffsetThe value which is given in the offset table to
compensate the difference
in length between primary & secondary tool is
known as length offset.

Diameter OffsetThe value which is given to compensate the
co-ordinate from the center of the tool to the
periphery is known as diameter offset.

Wear OffsetThe value which is given to compensate the worn
out of the tool is known as wear offset.

C.S
As
Per
Job,
Tool
&
Feed
Per
Rev.

Sl no

Material

Cutting
Tool

Feeds in
0.1

0.2

mm per
0.4

revolution
0.8

1.6

3.2

Cutting
1

2

3

4

5

6

7

8

9

10

11

12

Plain Carbon or

TCT

Cast Steel

60

45

34

25

19

236

200

170

67

56

34

25

19

14

11

100

85

71

24

20

24

17

12

8.5

6

118

95

75

24

20

16

11

8

5--6

95

75

60

50

16

13

50

40

32

27

8.5

6.7

9.5

6

48

38

32

10

8

48

27

18

14

9.5

118

95

80

67

125

85

56

36

530

450

400

355

85

63

48

34

450

375

335

300

63

53

43

36

HSS

Mild Steel

Speed

HSS
TCT

Alloy Steel

280

118

HSS
TCT

Mn-steel,Cr-Ni-steel

HSS

Cr-Mo-steel

TCT

Tool Steel

150

mm/min.

HSS
TCT

Other Steel Alloys

HSS
TCT

Cast Iron

HSS
TCT

Copper alloys Brass

600

HSS
TCT

Cast Bronze

140

HSS
TCT

Tin Bronze

60

500

HSS
TCT

355

280

236

200

180

Light Alloys

HSS

400

300

200

118

75

Pure Aluminium

TCT

1320

1120

950

850

710

Aluminium Alloys

HSS

100

67

45

30

TCT

224

190

160

140

118

24

28

part programming (cnc)

More Related Content

What's hot

Similar to part programming (cnc)

More from SK MD RAIJUL HAQUE

Recently uploaded

part programming (cnc)