machine tool

1. Shaping, Planing
and Slotting
Operations
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Chapter 7

2. Production of Flat
Surfaces
Typical components with flat surfaces
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3. Production of Flat Surfaces..
Motions for producing Flat Surface
A
D
A'
E
B'
B
C
D
epth
of
cut
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4. Reciprocating Machine
Tools
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• different from rotary machine tools
• A single-point tool moves linearly
relative to the work part
•ShaperShapingtool moves
•PlanerPlaningworkpiece moves
•Slotter

5. Shaper/Shaping Machine
Tool
Base
Ram v
Workpiece
Vise
Table
f or d
Tool head
d or f
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Column

6. Shaper/Shaping Machine
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Main Parts
Base
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)

7. Shaping Operation
Cutting action and functioning of
clapper box in a shaper
Tool cleared
from machined
surface
Clapper box
(b) Return stroke
Lifted
clapper
box
Workpiece
(a) Forward/Cutting stroke
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8. Shaping Operation..
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9. Shaping Operation ..
Machining of inclined surface on shaping
machine

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
Workpiece
Inclined
machined
surface
Tool head & slide
(axis parallel to
machined surface)
Clapper box
(axis away from
toolhead)
Tool holder
located at a
convenient angle
Tool
Depth of cut
Movement
of the slide
for feed

10. Operating Conditions in a
Shaping Machine
m/min
where
N = the number of double strokes or cycles
of the ram per min (one double or full stroke
= one cutting and one return stroke)
L = Length of the ram stroke in mm
m = return stroke time/cutting stroke time
1000
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cutting speed v 
N L(1 m)

11. Operating Conditions in a
Shaping Machine ..
c Clearance
Cutting Stroke
Return Stroke
Workpiece
Length of stroke L
Length of Stroke L = Lj + 2 c
c Lj
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12. Operating Conditions in a
Shaping Machine ..
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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/stroke because no cutting
is done in return stroke

13. Operating Conditions in a
Shaping Machine ..
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Depth of Cut d
• Depth of cut d is 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

14. © rkm2003
Machining Time
Width cut in 1 stroke = f
Total width = w
No. of strokes to m/c total surface = w/f
Strokes/mm = N
Time for machining surface is
t = w/(f N) min

15. Machining Time
min
1000v f
w

Lw(1 m)
f N
t 
1000 L(1 m)
Machining time
From cutting speed
v 
N L(1 m)
 N 
1000 v
Time for machining w x L surface
min
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w
f N
t 

16. Material Removal Rate
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• Material removal rate (MRR)
MRR = f d L N(1+m) mm3/min
where d is depth of cut in mm
f is feed in mm/stroke;
N is strokes/min
L is length of stroke in mm
m is ratio of return stroke time to
cutting stroke time

17. Planer
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18. Planer/Planing Machine
Tool head
Housing
Tool heads
Tool head
Reciprocating
table
Bed
Guideways
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19. Types of Planing Machines
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• Open Side Planer
• Double Housing Planer
• Edge planer
• Universal planer,
• Pit type planer

20. Operating Conditions in a
Planer
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• Operating conditions in planer are
similar to Shaping Machine
Cutting Speed: Workpiece reciprocates
cutting time=return time
Cutting Tool: Multiple cutting tools cut
simultaneously
Job: Large size or multiple workpieces

21. Size of Shaping and Planing
Machines
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• Largest Size of Workpiece that can
be Machined
L x w x h

22. Difference between Shaper and
Planer
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• Size of Workpiece
• Movement of Tool and Workpiece
• Construction
• Cutting and Return Speeds
• Number of toolheads

23. © rkm2003
Slotting
Ram
Tool
Base
Tool
holder
Column
Table
Typical Job
Slotter/Slotting Machine
Slot made
by slotting

24. Example 7.1
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Find the machining time required for machining
the surface 600  800 mm, on a shaping
machine. Assume, cutting speed as 8 m/min.
The return to cutting time ratio is 1:4, and the
feed is 2 mm/double stroke. The clearance at
each end is 70 mm.
• Solution
Lj = 600 mm, w = 800 mm, v = 8 m/min,
m = ¼, f = 2 mm/stroke, c = 70 mm

25. Example 7.1 ..
• Given clearance at each end: c=75 mm
• length of stroke:
L = 600 + 270 = 740 mm
 8.65strokes/min
v 
N L(1 m)
 N 
1000v
1000 L(1 m)
 46.25 min
w
f N
t 
Assume 8.65 strokes/min available
• Machining time for 800 mm width
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26. Example 7.1 ..
• Alternately:
1000v f

740800(1 0.25)
t 
L w(1 m)
100082
 46.25 min
Assumptions:
N?
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27. Examples
• Example 7.2: Estimate the time required to
machine a cast iron surface 250 mm long and
150 mm wide on a shaper with cutting-to-
return ratio of 3/2. Use a cutting speed of 21
m/min, a feed of 2 mm/stroke and a clearance
of 25 mm. The available ram strokes on the
shaper are: 28, 40, 60 and 90 strokes/min.
Also, determine MRR assuming depth of cut
as 4 mm.
• Solution
• Given data: Lj = 250 mm, f = 2 mm/double
stroke, w = 150 mm,
• c = 25 mm, v = 21 m/ m/min, d = 4 mm
© r
•km
T2
h00
e3
cutting-to-return ratio of 3/2 gives m = 2/3

28. © rkm2003
Examples
• Given clearance is 25 mm, hence,
• L = 250 + 2  25 = 300 mm.
• We know that (Equation (1))
• SPEED v = NL(1+m)/ 1000 m/min
• From the above equation, we find
number of double strokes N per minute
required as
• N = 42 strokes/min

29. Examples
• Nearest available ram strokes is 40
strokes/min. Since calculated value is more
than 40, this is chosen. Normally, we should
not exceed the specified cutting speed, as it
will affect the tool life adversely. Hence,
select N = 40 strokes/min.
• With a chosen value of N, we cannot use
Equation (5) for time calculation. Hence,
substituting all the values in Equation (6),
we get
•
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• 2003
t = 150 / (402)
= 1.88 minutes