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Shaping, Planing Shaping, Planing Shaping, Planing Shaping, Planing and Slotting and Slotting and Slotting and Slotting OperationsOperationsOperationsOperations

Chapter 7

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Production of Flat Production of Flat Production of Flat Production of Flat SurfacesSurfacesSurfacesSurfaces

Typical components with flat surfaces

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Production of Flat Surfaces..Production of Flat Surfaces..Production of Flat Surfaces..Production of Flat Surfaces..Motions for producing Flat Surface

A

D

Feed

A'

Cut

E

B

'B

CWorkpiece

Dep

tho

f cu

t

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Reciprocating Machine Reciprocating Machine Reciprocating Machine Reciprocating Machine ToolsToolsToolsTools

• 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

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Shaper/Shaper/Shaper/Shaper/Shaping MachineRam

ToolWorkpiece

Vise

Base

v

Table

f or d

Tool head

d or f

Column

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Shaper/Shaper/Shaper/Shaper/Shaping MachineMain 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 OperationShaping OperationShaping OperationShaping OperationCutting action and functioning of

clapper box in a shaper

Tool cleared

from machined

surface

Clapper box

Workpiece

(b) Return stroke

Lifted

clapper

box

(a) Forward/Cutting stroke

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Shaping Operation..Shaping Operation..Shaping Operation..Shaping Operation..

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Shaping Operation ..Shaping Operation ..Shaping Operation ..Shaping Operation ..Machining of inclined surface on shaping

machine

θ

Tool

θ

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

Depth of cut

Movement

of the slide

for feed

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Operating Conditions in a Operating Conditions in a Operating Conditions in a Operating Conditions in a Shaping MachineShaping MachineShaping MachineShaping 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

)1( mLNvspeedcutting

+=

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Operating Conditions in a Operating Conditions in a Operating Conditions in a Operating Conditions in a

Shaping MachineShaping MachineShaping MachineShaping Machine ..

Length of Stroke L = Lj + 2 c

Workpiece

c c Clearance

Return Stroke

Cutting Stroke

Length of stroke L

Lj

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Operating Conditions in a Operating Conditions in a Operating Conditions in a Operating Conditions in a Shaping Machine ..Shaping Machine ..Shaping Machine ..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/stroke because no cutting

is done in return stroke

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Operating Conditions in a Operating Conditions in a Operating Conditions in a Operating Conditions in a Shaping Machine ..Shaping Machine ..Shaping Machine ..Shaping Machine ..

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

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Machining TimeMachining TimeMachining TimeMachining Time

Width cut in 1 stroke = fTotal width = wNo. of strokes to m/c total surface = w/fStrokes/mm = NTime for machining surface is

t = w/(f N) min

f mmw mm L mm

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Machining TimeMachining TimeMachining TimeMachining Time

Machining time

min1000

)1(

fv

mwL

Nf

wt

+==

From cutting speed

)1(

1000

1000

)1(

mL

vN

mLNv

+=⇒

+=

Time for machining w x L surface

minNf

wt =

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Material Removal RateMaterial Removal RateMaterial Removal RateMaterial Removal Rate• Material removal rate (MRR)

MRR = f d L N(1+m) mm3/min

where d is depth of cut in mmf is feed in mm/stroke;N is strokes/min L is length of stroke in mmm is ratio of return stroke time to cutting stroke time

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PlanerPlanerPlanerPlaner

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Planer/Planing MachinePlaner/Planing MachinePlaner/Planing MachinePlaner/Planing Machine

Tool headBed

Tool head

Tool heads

Housing

Reciprocating

table

Guideways

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Types of Planing MachinesTypes of Planing MachinesTypes of Planing MachinesTypes of Planing Machines

• Open Side Planer

• Double Housing Planer

• Edge planer

• Universal planer,

• Pit type planer

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Operating Conditions in a Operating Conditions in a Operating Conditions in a Operating Conditions in a PlanerPlanerPlanerPlaner

• Operating conditions in planer are similar to Shaping Machine

Cutting Speed: Workpiece reciprocatescutting time=return time

Cutting Tool: Multiple cutting tools cut simultaneously

Job: Large size or multiple workpieces

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SSSSiiiizzzzeeee ooooffff SSSShhhhaaaappppiiiinnnngggg aaaannnndddd PPPPllllaaaannnniiiinnnngggg MachinesMachinesMachinesMachines

• Largest Size of Workpiece that can

be Machined

L x w x h

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DDDDiiiiffffffffeeeerrrreeeennnncccceeee bbbbeeeettttwwwweeeeeeeennnn SSSShhhhaaaappppeeeerrrr aaaannnndddd PlanerPlanerPlanerPlaner

• Size of Workpiece• Movement of Tool and Workpiece• Construction • Cutting and Return Speeds• Number of toolheads

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Slotting

Ram

Tool

Base

Tool

holder

Column

Table

Typical Job

Slotter/Slotting Machine

Slot made

by slotting

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Example 7.1Find 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.

• SolutionLj = 600 mm, w = 800 mm, v = 8 m/min,

m = ¼, f = 2 mm/stroke, c = 70 mm

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Example 7.1 ..• Given clearance at each end: c=75 mm

• length of stroke: L = 600 + 2×70 = 740 mm

nstrokes/mi65.8)1(

1000

1000

)1(=

+=⇒

+=

mL

vN

mLNv

min25.46==Nf

wt

Assume 8.65 strokes/min available

• Machining time for 800 mm width

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Example 7.1 ..

• Alternately:

min25.46

281000

)25.01(800740

1000

)1(

=

××

+××=

+=

fv

mwLt

Assumptions:Assumptions:Assumptions:Assumptions:

N?N?N?N?

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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• The cutting-to-return ratio of 3/2 gives m = 2/3

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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

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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

• t = 150 / (40×2)• = 1.88 minutes