Senior Seminar
Presentation On : CNC Machines
Under Supervisor : Prof.Dr/ Ahmed Amin
Engineer/ Mostafa Shoeib
Team Names : • Karim Atef 171047
• Ahmed Nasser 171134
• Ahmed Abdelhamed 171140
• Omar Gharib 171199
• Mohamed Mahmoud 171225
• Begad Zaki 171272
1. Introduction to CNC machines
CO:- Develop part program for CNC
Turning, Milling and verify on simulation
software.
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Contents
• Introduction to CNC
• Operations in CNC
• Advantages and Disadvantages of CNC
• Axis selection
• 5 Axis CNC
• Advantages and application of 5 axis
• Types of machine configurations for 5-axis machining
• Specification of a 5 axis CNC machine
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Introduction to CNC
Numerical control (NC) is the automation of machine
tools that are operated by precisely programmed
commands encoded on a storage medium, as opposed to
controlled manually.
Most NC today is computer numerical control (CNC),
in which computers play an integral part of the control.
In modern CNC systems, end-to-end component design
is highly automated using computer-aided design
(CAD) and computer-aided manufacturing (CAM)
programs.
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Operations in CNC
CNC Milling
CNC Plasma Cutter CNC Electric Discharge 55
Machining 5
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Other CNC Operations are:-
CNC Water Jet Cutter
Drilling
Sheet metal works (Turret punch)
Wire bending machines
Surface grinders
Cylindrical grinders
submerged welding
Glass cutting
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Advantages of CNC
CNC machines can be used continuously
Batch production with high accuracy
can be updated by improving the software
Training in the use of CNCs is available through
the use of ‘virtual software’.
Intricate detail machining
no need to make a prototype or a model
One person can supervise many CNC machines
simultaneously
saves time
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Disadvantages
more expensive than manually operated machines
The CNC machine operator only needs basic
training and skills, enough to supervise several
machines. In years gone by, engineers needed years
of training to operate centre lathes, milling machines
and other manually operated machines. This means
many of the old skills are been lost.
Investment in CNC machines can lead to
unemployment
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Axes of CNC Machine Tool
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From 3-axis to 5-axis machining
• not sufficient for the • dozens of views need to be defined
complete • more tool movements
finishing process for very • programming is quite difficult
deep part and having narrow • sum of all views does not cover the
cavities whole geometry
• results in a bad surface • overlapping views lead to surface
quality and long machining quality problems
times in Case of harder • More number of lead-in and out
material movements
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Five Axis CNC
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ADVANTAGES OF 5 AXIS CNC
to machine complex shapes in a single setup
reduces the machinist setup time and increases production rates
By eliminating multiple set-ups, time and errors are reduced
the feature-to-features accuracy is improved because the same
zero or datum reference frame is used throughout the
manufacturing process
since simultaneous movement is allowed along the X and Y axis,
shorter and more rigid tools may be used
higher spindle/cutting tool speeds may be achieved while
reducing the load on the cutting tool
Shorter and thicker cutters also reduce vibration when
machining deep pockets or contoured features with three-axis
machines.
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Application
complex three dimensional profiles
for impellers, turbine blades, and plastic mold
tools
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Types of machine configurations for 5-axis
machining
Swivel Head with Integrated Trunnion Traveling Column
Rotary Table Table 15
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Specification of a 5 axis CNC Machine
Manufacturers
HURCO
TARUS
CMS north America
OKUMA
CNC TAKANG Taiwan
maximam corporation
YCM (YEONG CHIN MACHINERY INDUSTRIES CO., LTD )
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Specification cont…
TARUS TPGM5X1083 SPECIFICATIONS
Parameters
X Axis Travel 3048 mm
Y Axis Travel 2540 mm
Z Axis Travel 1117 mm
Space between columns 3886 mm
Workable size,L*W 3568 mm*2235 mm
X , Y and Z axis maximum feed rate 30m/min
A axes tip +/-100 degrees
C axis tip Continuous
A and C axis positioning peak torque 4073 NM
A and C axis positioning Feed 30 degrees per second
Milling Spindle HSK 63A, 0-20,000 RPM
(3 axis and 5 axis milling)
4,000 RPM base speed
70 NM constant torque,160 NM peak torque
29 KW rated power
Linear Accuracy (X,Yand Z) ± .013 mm , ± 0.006 mm, ± 0.005 mm
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CONTENTS
1. HISTORY
2. CNC INTRODUCTION
3. HOW THEY LOOK LIKE?
4. ELEMENTS OF CNC
5. BLOCK DIAGRAM OF CNC
6. HOW CNC WORKS?
7. FEATURES OF CNC MACHINES
8. CNC PROGRAMMING BASICS
9. COMMON FORMAT OF A BLOCK
10. PROGRAMMING KEY LETTERS
11. TABLE OF IMPORTANT G-CODES
12. TABLE OF IMPORTANT M-CODES
13. ADVANTAGES
14. CHALLENGES
15. CONCLUSION
16. REFERENCES
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History
The first NC machines were built in
the 1940s and 1950s by Prof. John T
Parson.
CNC machine came into existence
after evolution of computer around
1980.
Modern CNC Machine are improving
further as the technology is changing
with a variety of functions according
to applications.
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CNC Introduction
A numerical control
system in which the
data handling, control
sequences, and
response to input is
determined by an on-
board computer system
at the machine tool.
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CNC Machines- How do they look like?
Servo Motors
Display Console
Automated Coolant
Tool changer control
Controller
Slides
Controller
Chip collection and removal
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Elements of CNC Machine
A CNC machine consist of
following 6 major elements:
i. Input Device
ii. Machine Control Unit
iii. Machine Tool
iv. Driving System
v. Feedback Devices
vi. Display Unit
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Block diagram of CNC Machine
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Open loop and Closed loop controls
In open loop systems the slide may overshoot or may not reach
desired position because of inertia, wear and tear and friction,
hence inaccurate machining.
In closed loop systems the position sensors are used to correct
slide movements and achieve higher accuracy and repeatability
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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.
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Features of CNC Machinery
The tool or material moves automatically.
Tools can operate in 1-5 axes.
Larger machines have a machine control unit
(MCU) which manages operations.
Movement is controlled by motors (actuators).
Feedback is provided by sensors (transducers)
Tool magazines are used to change tools
automatically.
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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.
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CNC programming
Important things to know: Programming consists of a series
of instructions in form of letter codes
Coordinate System
•Preparatory Codes:
Units, incremental or G codes- Initial machining setup and
absolute positioning establishing operating conditions
N codes- specify program line number
Coordinates: X,Y,Z, to executed by the MCU
RX,RY,RZ
•Axis Codes: X,Y,Z
Used to specify motion of the slide along
Feed rate and spindle
speed X, Y, Z direction
•Feed and Speed Codes: F and S
Coolant Control: On/Off,
Flood, Mist Specify feed and spindle speed
•Tool codes: T – specify tool number
Tool Control: Tool and
tool parameters •Miscellaneous codes – M codes
•For coolant control and other activities 28
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Common Format of a Block
Sequence Preparatory Dimension Feed Spindle Tool Misc.
# Function Words Rate Functio Functio Function
n n
N50 G90 G01 X1.40Y2.25 F10 S1500 T01 M03
Individual
Words 29
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Programming Key Letters
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
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Table of 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
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Table of Important M codes
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
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Advantages of CNC
i. - Easier to program;
ii. - Easy storage of existing programs;
iii. - Easy to change a program
iv. - Avoids human errors
v. - CNC machines are safe to operate
vi. - Complex geometry is produced as cheaply as simple ones
vii. - Usually generates closer tolerances than manual machines
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CHALLENGES
i. Costly setup, skilled operators
ii. Computers, programming
knowledge required
iii. Maintenance is difficult
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Conclusion
The advantage of a CNC system are that the
operation of a conventional machine is removed
and the part production is made automatic.
It reduces the labor work and hence highly
efficient in the manufacturing process.
BHEL generally uses CNC machines to achieve
its manufacturing targets. For manufacturing
works of large scale it is very difficult to work
with manual machines as they are time
consuming. CNC machines have their wide
scope because they are easy to handle, the work
becomes easier and jobs are done with
perfection.
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Thank You
