Title: SEMINAR ON HIGH SPEED MACHINING (HSM)
1SEMINAR ONHIGH SPEED MACHINING (HSM)
2CONTENTS
- Introduction
- Definition of HSM
- Advantages
- Application areas
- Machining system
- Some recommended parameters
- Comparison
- Disadvantages
- Conclusion
3DEFINITION 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
4DEFINITIONS
- 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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6ADVANTAGES
- 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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8 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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10APPLICATION 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.
11MACHINING 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. -
12DEMANDS 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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15CUTTING TOOLS
- TiN and TiCN coated Carbide for materials with
hardness less than 42 HRC - TiALN coated Carbide for materials with hardness
42 HRC and above - For special applications like hard turning
(HRC 60-65) PCBN is used - Cubic boron nitrite (CBN) and ceramic for cast
iron - Poly crystalline diamonds (PCD) and Cermets are
used for aluminum
16RECOMMENDED 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.
19COMPARISONS
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
20Comparison 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
23DISADVANTAGES
- 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
24CONCLUSIONS
- 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.
26THANK YOU