Question No. 1

What is the difference between Shear and Tensile strength?

Answer:                         

Tensile Strength for a Bolt is determined by applying a Force along it long axis. Shear

Strength for a Bolt is determined by applying a Force across its diameter, as it would be loaded in a lug joint. Tensile strength is strength in tension when pulling force is applied. And shear strength is strength against cutting force which is known as shear force.

Question No. 2

What is the difference between Tensile strength and tensile modulus?

Answer:

Tensile strength is the ultimate capacity of the material to resist a tensile load regardless of deflection.

Tensile modulus also known as Young’s modulusis a measure of the stiffness of anisotropic elastic material. It is defined as theratio of the uni-axial stress over the uni-axialstrain. It is determined from the slope of astress-strain curve traced during tensile testsconducted on a sample of the material.

Question No. 3

What is OEE?

Answer:

OEE means Overall Equipment Effectiveness.

This terminology widely used in Total productive maintenance, which is used to calculate the effectiveness of machines in manufacturing. Basically it captures the losses of machines in production and tries to improve defects on machines. Higher the OEE, more capable is the machine.

Question No. 4

Why Involutes Curve used in Gear?

Answer:

Involute curveis the path traced by a point on a line as the line rolls without slipping on the circumference of a circle. Involute curve has a contact angle between two gears when the tangents of two gears pass through the contact point without friction.

Question No. 5

What is bearing stress?

Answer:

The stress which acts on the contact surface area between two members is known as bearing stress. An example for this is the stress between nut and the washer

Question No. 6

Which is hard material Cast Iron or Mild Steel?

Answer:

Cast iron. Due to the excess carbon content than mild steel it is harder. The more carbon content, the more hardness will be. But it reduces the Weldability due to this hardness.

It is brittle too.

Question No. 7

What are the materials used for Sliding Wear pad?

Answer:

1.     Urethane-Coated Base Material Provides Optimum Sliding Surfaces for Maximum Wear Ability.

2.     Galvanized Steel for Backing on Head and Side Pads.

3.     For crane services, we use Velcro Nylon wearing pad

Question No. 8

What is the difference between a Shaper machine and a Planner machine?

Answer:

In Shaper machine tool is having reciprocating motion and work piece is clamped on table which is stationary. It is mostly suitable for light duty operation. In Shaping large cutting force is transferred to tool. In Planer machine tool is having stationary and work piece is clamped on table which is reciprocating motion. It is mostly suitable for Heavy duty operation. In planner large cutting force is transferred to table.

Question No. 9

How will you calculate the tonnage of Mechanical Press?

Answer:

F = (S × L × T)/ 1000

F = Force in kilo Newton’s

S = shear stress of material in MPa

L = the total length of peripheries being cut/ sheared in mm T = thickness of material in mm

Question No. 10

What is the composition of Grey cast iron Grade 20?

Answer:

Carbon: 3.10 – 3.25%, Silicon: 1.75 – 1.95%, Manganese: 0.50 – 0.7%, Sulphur: 0.05 – 0.07%, Phosphorous: 0.04 – 0.07%