MACHINING - High-Speed-Machining-Ppt.ppt

HSM MACHINING PPT

2. SEMINAR ON
HIGH SPEED MACHINING
(HSM)
Prepared By:
NIZAR.A
S
7ME
No:4413

3. CONTENTS
Introduction
Definition of HSM
Advantages
Application areas
Machining system
Some recommended parameters
Comparison
Disadvantages
Conclusion

4. DEFINITION OF HSM
Carl Salomon assumes that
“At a certain cutting speed
which is 5-10 times
higher than in
conventional machining
the chip removal
temperature at the cutting
edge will start to
decrease”

5. DEFINITIONS
High cutting speed machining
High rotational speed machining
High feed machining
High speed and feed machining
High productive machining
Finally,
“HSM is a powerful machining method that combines
high feed rates with high spindle speeds, specific
tools and specific tool motion.”

7. ADVANTAGES
High material removal rate
High surface finish
Increased productivity
Possibility of machining of very thin walls
Reduction in lead times
Low cutting force
Cutting tool and work piece temperature are kept low
Connection time between the cutting edge and work piece is
short
It eliminates the need of coolant
Reduction of production process

9. FEATURES EFFECTS
Reduced heat
transfer in to the
work piece
Part accuracy
Reduction of
cutting forces
Part accuracy
Surface quality
Increased cutting
speed
Stability of rotating
cutting tool feed rate
Increased material
removal

11. APPLICATION AREAS
Industry which deals with the machining of Al to
produce automotive components, small computer
parts or medical devices
Aircraft industry involves machining of Al often
with thin walls
Die mould industry which requires dealing with
finishing of hard materials .
Used to machine such parts as die casting dies,
forging dies, injection moulds and blow moulds,
milling of electrodes in graphite and copper,
modeling and prototyping of dies and moulds.

12. MACHINING SYSTEM
MACHINE TOOLS
3-axis horizontal and vertical milling machines
CNC 4-axis milling machine offers the option of
tilting the milling cutters to improve the cutting
conditions
5-axis machine with inter changeable spindle units
allow to rough, semi finish and finish with a single
set up.

13. DEMANDS ON THE MACHINE
Spindle speed range <=40000 rpm
Spindle power >22 KW
Programmable feed rate 40-60 m/min
Rapid travels <90 m/min
Block processing speed 1-20 ms
High thermal stability and rigidity in spindle
Air blast/coolant through spindle
Advanced look ahead function in the CNC

16. CUTTING TOOLS
1.TiN and TiCN coated Carbide for materials with
hardness less than 42 HRC
2.TiALN coated Carbide for materials with hardness
42 HRC and above
3.For special applications like hard turning
(HRC 60-65) PCBN is used
4.Cubic boron nitrite (CBN) and ceramic for cast iron
5.Poly crystalline diamonds (PCD) and Cermets are
used for aluminum

17. RECOMMENDED PARAMETERS
1.True cutting speed
As the speed is dependent on both spindle speed
and diameter of tools HSM should be defined
as “true cutting speed” above a certain level

18. 2.Material removal rate
Material removal rate,
Q = (a
p* a
e * v
f)/1000 cm
3
/min
where a
p= vertical dist from tool tip to the
reference point mm
a
e= step over distance mm
v
f= feed speed mm/min

19. 3. Surface finish
Surface finish is depends upon cutting tool
geometry, coating of the cutting tool, wear
status of the cutting tool etc.

20. COMPARISONS
Conventional machineHigh speed machine
Max speed 600 m/minSpeed starts at 600 m/min
Max feed ~40 ipm Feed starts at 100 ipm
Require high levels
coolant
With coolant ,feed rate
can go more than 2000
ipm
No need for coolant for
low feed rate
Between conventional and high speed machines

21. Comparison between speeds used in conventional and high speed
machining

22. Conventional HSM
The contact time between
tool and work is large
Contact time is short
Less accurate work pieceMore accurate work piece
Cutting force is largeCutting force is low
Low surface finish High surface finish
Material removal rate is lowMaterial removal rate is
high
Cutting fluid is required Cutting fluid is not required
Comparison between convl and HSM process

23. HSM EDM
Material removal rate
high
Material removal rate is
low
Dimensional tolerance
0.02 mm
Dim tolerance
0.1-0.2 mm
There is no need of
making cutting tool
according to the contour
to be machined
Cutting tool has to be
made according to the
contour to be machined
Comparison between HSM and EDM

24. DISADVANTAGES
Need for expensive and special machine tools
with advanced spindle and controllers
Excessive tool wear
Good work and process planning necessary
It can be difficult to find and recruit advanced
staff

25. CONCLUSIONS
HSM is not simply high cutting speed .It should be
regarded as a process where the operations are
performed with very specific methods and precision
equipment
HSM is not necessarily high spindle speed
machining. Many HSM applications are performed
with moderate spindle speeds and large sized cutters
HSM is performed in finishing in hardened steel with
high speeds and high feeds often with 4-6 times
conventional cutting speeds

26. HSM is high productive machining in small
sized components in roughing to finishing and
in finishing to super finishing in components
of all sizes.
Even though HSM is known for a long time,
the research are still being developed for
further improvement of quality and
optimization of cost.