Common Data:
A cylinder is turned on a lathe with orthogonal machining principle. Spindle rotates at $200 r p m$ . The axial feed rate is $0.25 m m$ per revolution. Depth of cut is $0.4 m m$ The rake angle is $10^{o}$ . In the analysis it is found that the shear angle is ${27.75}^{o}$ .

In the above problem, the coefficient of friction at the chip tool interface obtained using Earnest and Merchant theory is

0.18

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0.36

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0.71

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0.98

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Solution

The correct option is D $0.98$
From Earnest and Merchant theory
$2 ϕ + β - α = 90^{o}$
$β = 90^{o} + α - 2 ϕ$
$β = 90^{o} + 10 - 2 \times {27.7}^{o}$
$∴ β = {44.56}^{o}$
$μ = t a n ({44.56}^{o}) = 0.98$

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Similar questions

Common Data:
A cylinder is turned on a lathe with orthogonal machining principle. Spindle rotates at $200 r p m$ . The axial feed rate is $0.25 m m$ per revolution. Depth of cut is $0.4 m m$ The rake angle is $10^{o}$ . In the analysis it is found that the shear angle is ${27.75}^{o}$ .

The thickness of the produced chip is

Q. In a turning operation with orthogonal machining the spindle rotates at 270 rpm and the tool is fed at a rate of 0.3 mm per revolution. The depth of cut is 0.5 mm. The rake angle is

10^{\circ}

and the coefficient of friction at the tool chip interface to be 0.5317. What is the value of chip thickness?

Q. The following data are obtained during orthogonal machining with Merchants theory.

Ultimate shear strength of work material = 600 MPa,
Rake angle of the tool

= 6^{\circ}

,
Coefficient of friction at chip tool interface

= 0.2

,
Feed and depth of cut = 0.2 mm/rev and 3 mm respectively. Taylor's tool life equation is

V . T^{0.4} = 100

.

The power required during machining operation is

Q. The following data are obtained during orthogonal machining with Merchants theory.

Ultimate shear strength of work material = 600 MPa,
Rake angle of the tool

= 6^{\circ}

,
Coefficient of friction at chip tool interface

= 0.2

,
Feed and depth of cut = 0.2 mm/rev and 3 mm respectively. Taylor's tool life equation is

V . T^{0.4} = 100

.

What is the Optimum cutting velocity during machining if machine hour rate is Rs. 75 and cost of regrinding the tool one time is Rs. 15?

Linked Data:
A $ϕ 40 m m$ job is subjected to orthogonal turning by $a + 10^{o}$ rake angle tool at $500 r e v / m i n$ . By direct measurement during the cutting operation, the shear angle was found equal to $25^{o}$

If the friction angle at the tool chip interface is $58^{o} 10^{'}$ and the cutting force components measured by a dynamometer are $600 N$ and $200 N$ the power loss due to friction (in $k N m / m i n$ ) is approximately

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The correct option is D 0.98From Earnest and Merchant theory 2ϕ+β−α=90o β=90o+α−2ϕ β=90o+10−2×27.7o ∴β=44.56o μ=tan(44.56o)=0.98

The correct option is D $0.98$
From Earnest and Merchant theory
$2 ϕ + β - α = 90^{o}$
$β = 90^{o} + α - 2 ϕ$
$β = 90^{o} + 10 - 2 \times {27.7}^{o}$
$∴ β = {44.56}^{o}$
$μ = t a n ({44.56}^{o}) = 0.98$