SEMINAR ON HIGH SPEED MACHINING (HSM) - PowerPoint PPT Presentation

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SEMINAR ON HIGH SPEED MACHINING (HSM)

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HIGH SPEED MACHINING (HSM) CONTENTS Introduction Definition of HSM Advantages Application areas Machining system Some recommended parameters Comparison Disadvantages ... – PowerPoint PPT presentation

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Title: SEMINAR ON HIGH SPEED MACHINING (HSM)


1
SEMINAR ONHIGH SPEED MACHINING (HSM)
2
CONTENTS
  • Introduction
  • Definition of HSM
  • Advantages
  • Application areas
  • Machining system
  • Some recommended parameters
  • Comparison
  • Disadvantages
  • Conclusion

3
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

4
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.

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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

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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
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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.

11
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.

12
DEMANDS ON THE MACHINE
  • Spindle speed range lt40000 rpm
  • Spindle power gt22 KW
  • Programmable feed rate 40-60 m/min
  • Rapid travels lt90 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

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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

16
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

17
  • 2.Material removal rate
  • Material removal rate,
  • Q (ap ae vf)/1000 cm3/min
  • where ap vertical dist from tool tip to
    the reference point mm
  • ae step over distance mm
  • vf feed speed mm/min

18
  • 3. Surface finish
  • Surface finish is depends upon cutting tool
    geometry, coating of the cutting tool, wear
    status of the cutting tool etc.

19
COMPARISONS
Conventional machine High speed machine
Max speed 600 m/min Speed 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
20
Comparison between speeds used in conventional
and high speed machining
21
Conventional HSM
The contact time between tool and work is large Contact time is short
Less accurate work piece More accurate work piece
Cutting force is large Cutting force is low
Low surface finish High surface finish
Material removal rate is low Material removal rate is high
Cutting fluid is required Cutting fluid is not required
Comparison between convl and HSM process
22
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
23
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

24
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

25
  • 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.

26
THANK YOU
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