Name : S'M' Prasad'

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Department Of Technical Education, Andhra
Pradesh

• Name S.M. Prasad.
• Designation H.M.E.S.
• Branch Mechanical Engineering
• Institute Govt,Polytechnic,Warangal
• Year\semester V semester
• Subject Manufacturing technology-II
• Subject code M-505
• Topic Milling and Gear making
• Duration 50 mins
• Sub-topic Milling Cutters -I
• Teaching aids Visuals Diagrams

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Recap..

• In the last class we have learnt about,
• The constructional details of milling machines.
  
• Functions of each part of the machine.

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Objectives

• On completion of this period, you would be able
  to Know about,
• A milling cutter.
• The types of milling cutters.
• The features of milling cutters.

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Cutter, slab mill
work
Milling , cutters, operation
Fig. 1
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Milling cutter

• The cutting tool of a milling machine.
• Multi cutting-edged rotating tool.
• Most of them are made with high speed steel or
  special alloy steels.
• A carbide inserted tool permits very high cutting
  speeds.

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Milling cutter

• All cutters generally have two types of cutting
  teeth, straight or spiral teeth and form relieved
  teeth.
• Each milling cutter is identified by the outer
  diameter, thickness, no. of teeth and the bore
  diameter, apart from the material of the cutter.

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Milling Cutters - Types

• 1. Plain milling cutter. 2. Side milling cutter
• 3. Metal slitting saw 4. Angle milling
  cutter
• 5. End-mills 6. T-slot milling cutter
• 7. Slot- drill 8. Woodruff key slot
  milling cutter
• 9. Fly cutter 10. Form milling cutter.

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1.Plain milling cutter

• It has straight or helical cutting edges only on
  the periphery.
• Produces flat surfaces parallel to the cutter
  axis.
• Do not carry cutting edges on its sides.
• With more width it becomes a slab mill.

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Side of the cutter
Cutting edges
Bore of the cutter
Plain milling cutter
Fig.2
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1.Plain milling cutter

• Plain milling cutters are divided into
• 1. Light duty cutter
• Remove less material.
• Face width less than 20mm, straight teeth.
• Parallel to the axis.
• Face width more than 20mm, helical teeth with
  25º helix angle.

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Plain milling cutter
Fig.3
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1.Plain milling cutter

• 2. Heavy - duty plain milling cutter
• With wider face width and helical teeth, removes
  more material.
• Helix angle 25º to 45º, better shearing takes
  place.
• Gives a fine surface finish.

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Metal slitting saw
Slab mill
End mill, shell
milling cutters
Fig.4
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1.Plain milling cutter

• 3. Helical plain milling cutter
• Has an helix angle between 45º to 60º .
• Due to better shearing, provide better surface
  finish.
• Adapted for taking light cuts on soft materials.

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Helical cutting edges
Helical plain milling cutter
Fig.5
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2.Side milling cutter

• They have the cutting edges not only on the face
  , but also on both the sides of the cutter.
• Used for slot milling and side milling .
• Diameter of the cutter ranges from 50mm to 200mm.
• Width range is 5mm to 32mm.

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Side milling cutter
Fig.6
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2.Side milling cutter

• Plain side milling cutter
• Cutting edges or teeth are straight on face and
  both sides of the tool.
• Half-side milling cutter
• Cutting edges on the face and only one side of
  the cutter.
• Cutting edges may be helical or straight .
• Used for straddle milling operation.

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2.Side milling cutter

• C. Staggered teeth side milling cutter
• The teeth are arranged in an alternate helix
  pattern.
• Provides greater chip space .
• Used for deep slots.

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Cutting edges
Staggered teeth milling cutter
Fig.7
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2.Side milling cutter

• D. Interlocking cutters
• Formed with two half-side cutters with a spacer
  between
• the two.
• Used to mill a slot of standard width in one
  operation.
• The width of the cutter ranges from 10mm to
  32mm.
• Widely used for gang milling .

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3. Metal slitting saw

• Similar to plain milling cutter.
• Face width is very small.
• Standard saws are made thinner at the center than
  at the outer edge to provide clearance
• Used to mill thin deep slots and cut-off
  operations.

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Slab mill
Slitting saw
End mill, shank
End mill, shell
Fig.8
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3. Metal slitting saw

• a) Plain metal slitting saw
• Sides are slightly relieved to prevent jamming
  in the slots.
• Width of these saws ranges from 1.5mm to 5.0mm.
• b) Side teeth slitting cutter
• It has teeth on the sides also. Used for
  parting- off operations .

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Metal slitting saw
Fig.9
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3. Metal slitting saw

• c). Staggered teeth metal slitting saw
• Teeth are staggered on the face in a way similar
  to staggered teeth side milling cutter.
• Width of the saw ranges from 5mm to 8mm
• It has greater chip carrying capacity.
• Used for cut off operations in steel.

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Summary

• In this class , we have learnt about
• A milling cutter.
• Types of milling cutters.
• Plain milling cutter , side milling cutter and
  metal slitting saw.

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Quiz

• A side milling cutter will have cutting edges
• a) one side only
• b) on face
• c) on sides and face.
• d) none of the above

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Quiz

• The teeth of a Staggered tooth cutter are
• a) In alternate helix .
• b) Straight
• c) helical
• d) none of the above

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Quiz

• For smooth milling operation, the teeth preferred
  are
• a) side teeth
• b) helical
• c) straight teeth
• d) none

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Frequently asked Questions

• 1) List out the various types of peripheral
  milling cutters?
• 2) Differentiate between plain milling cutter and
  side milling cutter?
• 3) Why are helical teeth cutters superior to
  straight teeth cutters?