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Assistant Professor
Mechanical Engineering Department
NIT Warangal 506 004Disclaimer
The content presented here is not entirely my own. Some portions are taken from
different sources with great regard. This content is solely for class room teaching andnot for any commercial use.
T. SADASIVA RAO
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Basic geometry forshaping and planing
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Cutting tool in actionFig. Photographic view of a shapingmachine
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Fig. Principle of producing flat surface in shaping machine Version
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Production of Flat Surfaces..
Motions for producing Flat Surface
A
D
Feed
A'
Cut
E
B
'B
CWorkp
iece
De p
th
of
c u
t
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Reciprocating Machine Tools
differentfrom rotary machine tools
A single-point tool moves linearlyrelative to
the work part
ShaperShapingtoolmoves
PlanerPlaningworkpiecemoves
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Basics of Shaping
FIGURE: Basics of shaping and planing.
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Shaper
FIGURE: The most widely used shaper is the
horizontal push-cut machine tool
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Shaper/Shaping Machine
Main PartsBase
Column drive, support & guide ram
Table
hold & feed workpiece
Ram tool head, clapper box
Types of Shaping M/c Horizontal Shaper
Vertical Shaper (Slotting M/c)
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Shaping Operation ..
Machining of inclined surface on shapingmachine
Tool
Workpiece
Inclinedmachinedsurface
Tool head & slide(axis parallel tomachined surface)
Clapper box(axis away fromtoolhead)
Tool holder
located at aconvenient angle
Depth of cut
Movementof the slide
for feed
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Operating Conditions in a Shaping
Machine ..
Length of Stroke L = Lj+ 2 c
Workpiece
c c
Clearance
Return Stroke
Cutting Stroke
Len th of strokeLLj
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1. Table support
2. Table3. Clapper box
4. Apron clamping
bolt
5. Down-feed hand
wheel
6. Swivel base7. Position of stroke
adjustment hand
wheel
8. Ram locking
handle
9. Ram
10. Column
11. Driving pulley
12. Base
13. Feed discFig. Parts of a standard shaper 14. Pawl mechanism
15. Elevating screw
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Shaping Operation
Cutting action and functioning ofclapper box ina shaper
Tool cleared
from machinedsurface
Clapper box
Workpiece
(b) Return stroke
Lifted
clapperbox
(a) Forward/Cutting stroke
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1. Down-feed screw
micrometer dial
2. Down-feed screw
3. Vertical slide4. Apron
5. Apron clamping bolt
6. Clapper box
7. Tool post
8. Washer
9. Apron swivel pin10. Swivel base
Fig. Tool head of a shaper
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1. Driving pinion2. Ram
3. Screwed shaft
4. Clamping lever
5. Hand wheel for position of
stroke adjustment
6. 7. Bevel gears8. Ram block
9. Slotted link or Rocker arm
10. Bull gear sliding block
11. Crank pin
12. Rocker arm sliding block
13. Lead screw14. Bull gear
15. Rocker arm pivot
16. Bull gear slide
17. 18. Bevel gears
Fig. Crank and slotted link mechanism
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Fig. a) Crank pin near bull gear center Fig. b) Crank pin at farthest end
(Short stroke length) (Long stroke length)
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1. Driving pinion2. Ram
3. Screwed shaft
4. Clamping lever
5. Hand wheel for position of
stroke adjustment
6. 7. Bevel gears8. Ram block
9. Slotted link or Rocker arm
10. Bull gear sliding block
11. Crank pin
12. Rocker arm sliding block
13. Lead screw14. Bull gear
15. Rocker arm pivot
16. Bull gear slide
17. 18. Bevel gears
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1. Knob
2. Pin
3. Helical spring
4. Pawl5. Ratchet wheel
6. Rocker arm fulcrum
7. Rocker arm
connecting pin
8. Driving disc
9. Crank pin
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Production of Flat Surfaces
Typical components with flat surfaces
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FIGURE: Typical surfaces machined by shaping and planing.
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Machining
Horizontal surface Vertical surface Angular surface
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Operating Conditions in a Shaping Machine ..
Feed f Feed f is the relative motion of the workpiece in a direction
perpendicular to the axis of reciprocation of the ram
Feed is expressed in mm/double stroke or simply mm/strokebecause no cutting is done in return stroke
Depth of Cut d
Depth of cut dis the thickness of the material removed in one cut, in mm
Depth of cut may be given by the tool head slide or by lifting the table
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Machining Time
Width cut in 1 stroke =fTotal width = w
No. of strokes to m/c total surface = w/fStrokes/mm = NTime for machining surface is
t= w/(f N) min
f mm
w
mm L mm
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Machining Time
Machining time
min
1000
)1(
fv
mwL
Nf
wt
From cutting speed
)1(
1000
1000
)1(
mL
vN
mLNv
Time for machining wx L surface
minNf
wt
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Machining Time
Machining time
min
1000
)1(
fv
mwL
Nf
wt
From cutting speed
)1(
1000
1000
)1(
mL
vN
mLNv
Time for machining wx L surface
minNf
wt
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Material Removal Rate
Material removal rate(MRR) MRR = f d L N(1+m) mm3/min
where dis depth of cut in mm
f is feed in mm/stroke;
N is strokes/min
L is length of stroke in mmm is ratio of return stroke time tocutting stroke time
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Cutting tool in actionFig. Photographic view of a planingmachine
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Schematic of a Planer
FIGURE: Schematic of planers. (a) Double-housing planer with multiple tool
heads (4) and a large reciprocating table; (b) single-housing or open-sided
planer; (c) interchangeable multiple tool holder for use in planers.
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Shaper PlanerThe tool reciprocates while the work is The work reciprocates while the tool isgiven the feed motion. given the feed motion.
Jobs of small size Larger jobs
Accuracy of work is low because of Accuracies are high as the tool isoverhang of the ram. rigidly supported.
Small depths of cut because of less Large depths of cut because of highrigidity rigidity.
Single job Multiple jobs can be machined with the
help of multiple tooling heads.
Work set up is simple Work set up takes longer time.
Relatively lighter, smaller and less Relatively heavier, larger and costliercostly