Important Mechanical Interview Questions and Answers Part 1

Important Mechanical Interview Questions and Answers

Hello Friends, I've collected some interview questions based on my experience in mechanical field.

I have some Technical, Tricky and Logical questions. Whether you are fresher or experienced, this questions will boost your knowledge and helpful for you in future.

Question 1. What are the different types of fits?

Answer- On the basis of Indian standards fits mainly categorized into three groups
i.   Clearance Fit
ii.  Interference Fit
iii. Transition Fit

Question 2. What is difference between lathe and milling machine?

Answer- Both machine performs metal removing process but
i.  In lathe machine job are moving and tool is fixed
ii. In milling machine job are fixed and tool is moving.

Question 3. What is stress?

Answer- Stress is defined as force applied over an area which cause a material to deform.
It's unit is N/m² and symbol is sigma σ

Question 4. Draw the top view, side view and front view of the given object.

Answer- In this any component is given by interviewer and you have to draw it's Front view, Side view and top view using either First angle projection method or Third angle projection method.

Question 5. Convert 1 atm pressure in different units.

Answer- 
1 atm Press. = 1.01325 bar
1 atm Press. = 101325 Pascal
1 atm Press. = 14.69 Psi
1 atm Press. = 760 mm of Hg
1 atm Press. = 10.33 m of water column

Question 6. Least counts of measuring instruments

Answer- Least count of some commonly used instruments are mentioned below
Analog Vernier caliper = 0.02 mm
Digital Vernier caliper = 0.01 mm
Analog micrometer = 0.01 mm
Digital micrometer = 0.001 mm
Steel Scale = 0.5 mm
Vernier Height gauge = 0.02 mm
Digital Height gauge = 0.01 mm
Simple Protractor = 0.5 degree
Bevel Protractor = 5 minutes
Dial Gauge = 0.01 mm

Question 7. What are the different types of manufacturing processes?

Answer- There are primary 4 types of manufacturing processes
i. Casting & Moulding - which includes centrifugal casting, die casting, sand casting, shell moulding, plastic injection moulding etc.
ii. Machining - Milling, turning, drilling, honing, finishing, laser cutting etc.
iii. Joining - Welding, brazing, soldering, sintering, press fitting etc.
iv. Shearing $ Forming - Shearing, forging, rolling, extrusion, pressing, bending etc.

Question 8. What are the different types of welding processes?

Answer- There are 4 main types of welding processes
i. Gas Welding
ii. Resistance Welding
iii. Energy Beam Welding
iv. Arc Welding
Arc Welding is classified as

A. Consumable Electrode Method
a. Stick Welding (Shielded Metal Arc Welding or SMAW)
b. MIG Welding
c. Flux-Cored Arc Welding (FCAW)
d. Submerged Arc Welding (SAW)

B. Non Consumable Electrode Method
a. TIG Welding
b. Electroslag Welding (ESW)
c. Automic Hydrogen Welding (AHW)
d. Carbon Arc Welding (CAW)
e. Electrogas Welding (EGW)

Question 9. What is the difference between first angle projection and third angle projection?

Answer- 

Question 10. What are the types of Heat Transfer?

Answer- There are 3 types of heat transfer
i. Conduction - This is a flow of heat by direct contact in same medium.
ii. Convection - This is a transfer of heat by mixing a fluid. Convection occurs within liquids and gases. i.e transfer of heat from one medium to another.
iii. Radiation - This dos not required any medium to transfer the heat.

Question 11. Draw the GD&T symbols against the mention characteristics.

Answer- In this type they gave you any characteristics and you have to draw the symbol or symbol is given and you have to write the characteristics.

For detail knowledge check my Geometric Dimensioning and Tolerancing page.

Question 12. Tell me about your project.

Answer- The first thing you need to do is prepare for this question in advance. As this is one of the common questions, you should very well be prepared with an effective answer.

Some of the points while preparing the answer are

1. Provide a best suitable example

2. Be clear and specific
3. Your role should be explained clearly
4. Brief them the mistakes to avoid

There are few things which any interviewer would expect from a project you have done previously irrespective of being a fresher or experienced. They are,
1. The way you solved a problem in the project.
2. Your role in the project.
3. Your imagination or creativeness in the concept of the project.

Question 13. What is the difference between QA and QC?

Answer- Quality Assurance is process orientation and focuses on defect prevention.

Quality Control is product oriented and focuees on defect identification.

For detail explanation please check my page Quality Assurance vs Quality Control

Question 14. Tell me the 7 Quality Tools.

Answer-

1. Histogram

2. Pareto Chart

3. Fishbone Diagram

4. Control Chart

5. Flow Chart

6. Scatter Diagram

7. Checksheet

Question 15. Difference between accuracy and precision?

Answer- 

Accuracy is Closeness of measured value to the actual value.

Precision is closeness of two or measurements to each other.

For detail explanation please check my page Accuracy vs Precision

Question 16. What is gear ratio?

Answer- 

Gear ratio is the number of revolution of pinion gear to one revolution of idler gear.

or

It is ratio of diameter of idler gear to pinion gear.