200+ Mechanical Engg. Design Interview Questions and Answers

I am proficient in AutoCAD, SolidWorks, and CATIA with over 3 years of experience in each software.

• Proficient in AutoCAD, SolidWorks, and CATIA

• Over 3 years of experience in each software

• Able to create 2D and 3D models, assemblies, and drawings

• Familiar with GD&T and ANSI standards

• Experience in designing mechanical components and systems

• Ability to work with large assemblies and complex geometries

Flat process is preferred in sheet metal fabrication for ease of manufacturing and cost-effectiveness.

• Flat process involves cutting and bending sheet metal in a single plane, reducing the need for complex tooling and machinery.

• It also allows for easier handling and transportation of the sheet metal.

• Flat process is more cost-effective than other processes like deep drawing or hydroforming.

• Examples of products made using flat process include metal cabinets, enclosures, and pane...read more

The pipe with 10mm diameter carrying Nitrogen will have higher mass flow rate due to higher density. The pipe with 8mm diameter carrying Helium will have higher volume flow rate due to lower density.

• Nitrogen has a higher density than Helium, so the pipe with 10mm diameter will have higher mass flow rate

• Helium has a lower density than Nitrogen, so the pipe with 8mm diameter will have higher volume flow rate

Alloy steel is used for its high strength and durability. It is made by adding other elements to iron.

• Alloy steel is made by adding other elements to iron to improve its properties.

• It is used for its high strength, durability, and resistance to corrosion.

• Some common types of alloy steel include stainless steel, tool steel, and high-strength low-alloy steel.

• Stainless steel contains chromium and nickel, making it resistant to rust and corrosion.

• Tool steel is used for making too...read more

Flanges are selected based on factors like pressure rating, material compatibility, and application requirements.

• Flanges are selected based on the pressure rating required for the specific application.

• Material compatibility is crucial in selecting flanges to ensure they can withstand the intended environment.

• Application requirements such as temperature, fluid type, and pipe size also influence flange selection.

• Common types of flanges include weld neck, slip-on, socket weld, a...read more

The pipe with the highest flow rate for the lowest diameter (4mm) will fill the tank fastest.

• The pipe with the smallest diameter (4mm) will have the highest flow rate for water flow.

• Smaller diameter pipes have higher flow rates due to higher velocity of water flow.

• Therefore, the 4mm diameter pipe will fill the tank fastest compared to the 5mm and 8mm diameter pipes.

Draw shear and bending moment diagrams for a cantilever beam.

• Calculate reactions at the support

• Determine the equation of the shear force diagram

• Determine the equation of the bending moment diagram

• Plot the diagrams using the equations

• Check for accuracy and consistency

Factor of safety is the ratio of the maximum stress a material can withstand to the actual stress it is subjected to.

• Factor of safety is used to ensure the safety and reliability of a design.

• It is calculated by dividing the ultimate strength of a material by the maximum stress it is expected to experience.

• A factor of safety greater than 1 indicates that the design is safe and can withstand the expected loads.

• For example, if a bridge is designed to support a maximum load of 10...read more

I have used SolidWorks and AutoCAD for designing in my previous job.

• I have experience in creating 3D models, assemblies, and drawings using SolidWorks.

• I have also used AutoCAD for 2D drafting and detailing.

• I am familiar with creating parametric models and using design tables in SolidWorks.

• I have worked on projects involving sheet metal design, weldments, and surface modeling.

• I have collaborated with other engineers and stakeholders to ensure designs meet requirements and stan...read more

A hydraulic pump is installed between a motor and a cylinder in a hydraulic system.

• A hydraulic pump is used to convert mechanical energy from the motor into hydraulic energy.

• The pump pressurizes the hydraulic fluid, which is then used to move the cylinder.

• The pump can be driven directly by the motor or through a system of gears or belts.

• Examples of hydraulic pumps include gear pumps, vane pumps, and piston pumps.

I have experience in designing hydraulic and pneumatic systems for various industrial applications.

• Designed hydraulic systems for heavy machinery like cranes and excavators

• Developed pneumatic systems for automated assembly lines

• Knowledge of fluid mechanics and control systems

• Experience in selecting appropriate components like pumps, valves, and actuators

• Familiarity with industry standards and safety regulations

There are 14 symbols in GD&T (Geometric Dimensioning and Tolerancing).

• GD&T uses symbols to communicate design requirements and tolerances.

• These symbols are used to specify the shape, size, and orientation of features on a part.

• Some common symbols in GD&T include concentricity, perpendicularity, flatness, and position.

• Each symbol has a specific meaning and is used to ensure proper functionality and interchangeability of parts.

• GD&T symbols are standardized and widely used in en...read more

Derive expressions for hoop stress and longitudinal stress in a pressure vessel.

• Hoop stress is the circumferential stress in the cylindrical wall of the vessel and is given by σh = pd/2t

• Longitudinal stress is the axial stress in the cylindrical wall of the vessel and is given by σl = pd/4t

• Where p is the internal pressure, d is the diameter of the vessel, and t is the thickness of the wall

• These stresses are important in designing pressure vessels to ensure they can withstand t...read more

Bending allowances are given to compensate for material stretching during bending process.

• Bending allowances are added to the flat pattern of a sheet metal part before bending.

• The amount of bending allowance depends on the material type, thickness, bend radius, and angle.

• Bending allowances are typically specified in a table or chart provided by the manufacturer.

• The bending allowance formula is: BA = (π/180) x R x (180 - α) x K

• Where R is the bend radius, α is the bend angle, a...read more

Sheet metal fabrication processes involve various techniques to shape and form sheet metal into desired products.

• Cutting: Techniques like shearing, laser cutting, and waterjet cutting are used to cut sheet metal into desired shapes.

• Bending: Sheet metal is bent using techniques like press brake bending or roll forming to create angles and curves.

• Forming: Processes like deep drawing, hydroforming, and stamping are used to shape sheet metal into complex forms.

• Joining: Welding, r...read more

Yes, I am knowledgeable about Fits & Tolerance and its application in mechanical design.

• Fits & Tolerance are used to ensure proper functioning of mechanical parts.

• It involves specifying the allowable deviation in dimensions of mating parts.

• Tolerance can be applied to various aspects such as size, shape, position, and orientation.

• Fits can be classified as clearance, interference, or transition fits.

• Examples of application include designing bearings, gears, and shafts.

• Proper ap...read more

The minimum draft angle for products with graining/texture, like car interior plastic parts, is typically 1-3 degrees.

• Draft angle is the angle between the vertical direction and the sidewall of a molded part.

• Graining or texture on plastic parts can make it difficult to release the part from the mold.

• A minimum draft angle of 1-3 degrees helps ensure easy ejection of the part from the mold.

• Insufficient draft angle can result in sticking, deformation, or damage to the part durin...read more

Tolerances are used in CAD drawings to ensure that the manufactured part meets the required specifications.

• Tolerances help to control the variation in dimensions and ensure that the parts fit together properly.

• They also help to reduce manufacturing costs by allowing for a range of acceptable dimensions rather than requiring every part to be made to exact specifications.

• Tolerances can be specified for various dimensions such as length, width, diameter, and angles.

• Examples of t...read more

Hollow and solid shafts with same cross section and load have different stress induced.

• The stress induced in the hollow shaft is less than that in the solid shaft.

• The stress is directly proportional to the distance from the neutral axis.

• The neutral axis is closer to the center of the solid shaft than the hollow shaft.

• The hollow shaft has more material away from the neutral axis, reducing stress.

• This is why hollow shafts are preferred in many applications, as they are lighter ...read more

Geometric Dimensioning and Tolerancing (GD&T) diagram for a rectangular box.

• Use basic GD&T symbols such as perpendicularity, flatness, and parallelism to specify the dimensions and tolerances of the box.

• Include datum features to establish a reference frame for the measurements.

• Consider the functional requirements of the box, such as its ability to stack or fit with other components.

• Use profile tolerance to control the overall shape of the box.

• Consider the manufacturing proces...read more

Pressure ratio for chocking condition is the critical pressure ratio at which the flow of a fluid becomes choked.

• The pressure ratio for chocking condition is the ratio of the outlet pressure to the inlet pressure at which the flow becomes choked.

• It is a critical parameter in the design of nozzles, valves, and other flow control devices.

• For air flowing through a nozzle, the pressure ratio for chocking condition is approximately 0.528.

Explanation of head load, plumbing load, water demand, fire load calculation, and system design of plumbing firefighting and HVAC systems.

• Head load is the pressure exerted by water on the plumbing system and is calculated using the formula P = ρgh.

• Plumbing load is the total load on the plumbing system and is calculated by adding the head load and friction loss.

• Water demand is the amount of water required by a building and is calculated based on the number of occupants and the...read more

Draw front, top, side, cross-section views and isometric of given product/model.

• Create a 2D drawing of the product/model from different angles

• Include dimensions and annotations

• Use appropriate scales for each view

• Create an isometric view to show the product/model in 3D

• Ensure accuracy and clarity in the drawings

Centre of gravity is the point where the entire weight of an object can be considered to act upon. Formula for an asymmetrical I section is (A1*d1 + A2*d2)/(A1+A2)

• Centre of gravity is important in designing structures and machines to ensure stability and balance

• It is the point where the object will balance perfectly in any orientation

• For an asymmetrical I section, the formula is (A1*d1 + A2*d2)/(A1+A2) where A1 and A2 are the areas of the two flanges and d1 and d2 are the dis...read more

Different types of stresses include tensile, compressive, shear, bending, and torsional stress.

• Tensile stress occurs when a material is pulled apart, like stretching a rubber band.

• Compressive stress occurs when a material is pushed together, like squeezing a sponge.

• Shear stress occurs when a material is twisted or cut, like cutting a piece of paper with scissors.

• Bending stress occurs when a material is bent, like bending a piece of wire.

• Torsional stress occurs when a material...read more

First angle and third angle projection are two methods used in engineering drawing to represent a 3D object on a 2D plane.

• First angle projection is commonly used in Europe and Asia, while third angle projection is commonly used in North America.

• In first angle projection, the object is placed in the first quadrant and the views are projected onto the planes behind the object.

• In third angle projection, the object is placed in the third quadrant and the views are projected onto ...read more

Failure may occur at the fixed support, near the point of application of the force, or at the junction of the beam and the support.

• Failure may occur at the fixed support due to excessive bending moment.

• Near the point of application of the force, failure may occur due to shear stress.

• At the junction of the beam and the support, failure may occur due to a combination of bending and shear stresses.

In CREO, features can be copied in parts and parts can be copied in assemblies using the Copy/Paste feature.

• To copy a feature in a part, simply select the feature and use the Copy/Paste function.

• To copy parts in an assembly, select the part(s) you want to copy and use the Copy/Paste function.

• You can also use the Mirror feature to create a mirrored copy of a feature or part.

• Copying features and parts can help in reusing designs and saving time in the design process.

6-sigma, 8D, and FMEA are quality control methodologies used in engineering to identify and eliminate defects.

• 6-sigma is a data-driven approach to eliminate defects and reduce variability in processes.

• 8D is a problem-solving methodology used to identify, correct, and prevent recurring problems.

• FMEA is a proactive approach to identify and eliminate potential failures in a product or process.

• All three methodologies are used to improve product quality, reduce costs, and increase...read more

The gear ratio of the pulley and driven is selected based on the desired speed and torque of the system.

• Determine the required output speed and torque

• Calculate the input speed and torque

• Select a gear ratio that matches the input and output requirements

• Consider factors such as efficiency, noise, and cost

• Perform testing and adjustments as necessary

An involute gear is a type of gear with teeth that are cut in an involute shape. Module is the size of the gear tooth. Quality parameters include pitch, pressure angle, and tooth profile. Errors in gear profile include tooth thickness variation, runout, and backlash.

• Involute gear has teeth cut in an involute shape

• Module is the size of the gear tooth

• Quality parameters include pitch, pressure angle, and tooth profile

• Errors in gear profile include tooth thickness variation, runo...read more

To start the drawing, I would carefully analyze the provided diagram and gather all necessary information.

• Examine the overall layout and dimensions of the diagram

• Identify key components and their relationships

• Determine the scale and units of measurement

• Consider any specific design requirements or constraints

• Sketch a rough outline of the drawing to establish the framework

• Add details and dimensions gradually, referring to the diagram as needed

Drawings are not made in 2nd or 4th angle due to confusion and complexity.

• 2nd and 4th angle projections are rarely used in industry

• They can cause confusion and complexity in interpreting the drawing

• 1st and 3rd angle projections are more commonly used and easier to understand

Bonus tolerance in GD&T is an additional tolerance that allows for variations beyond the specified limits.

• Bonus tolerance is used to provide flexibility in manufacturing processes.

• It allows for variations in dimensions or positions beyond the specified tolerances.

• Bonus tolerance can be applied to individual features or the entire part.

• It helps to ensure functional fit and assembly of components.

• For example, if a hole is specified to have a diameter of 10mm with a tolerance of...read more

Stress concentration can be reduced by using fillets, chamfers, and blending corners.

• Using fillets and chamfers to smooth out sharp corners

• Blending corners to distribute stress evenly

• Using multiple holes instead of a single hole

• Using a gradual change in cross-section instead of a sudden change

• Using materials with higher ductility

• Using surface treatments like shot peening or grinding

• Avoiding sharp corners and notches

Important parameters for stator assembly in housing

• Proper alignment of stator and housing

• Correct torque applied to fasteners

• Adequate clearance for cooling and ventilation

• Proper insulation and grounding

• Accurate placement of bearings and seals

The least count for a Vernier caliper is the smallest measurement that can be read accurately.

• The least count of a Vernier caliper is determined by the number of divisions on the main scale and the Vernier scale.

• The formula to calculate the least count is: Least Count = Value of one main scale division / Number of divisions on the Vernier scale.

• For example, if the value of one main scale division is 1 mm and the Vernier scale has 10 divisions, the least count would be 0.1 mm....read more

Both gas and liquid pressure vessels can be difficult to design, depending on various factors.

• The difficulty of designing a pressure vessel depends on factors such as the properties of the gas or liquid, the desired pressure and temperature, and the material used for construction.

• Gas pressure vessels may require additional considerations such as compressibility and potential for explosion or leakage.

• Liquid pressure vessels may require considerations such as thermal expansion ...read more

Ferrous components contain iron, while non-ferrous components do not.

• Ferrous components are magnetic, while non-ferrous components are not.

• Ferrous components are prone to rust and corrosion, while non-ferrous components are more resistant.

• Examples of ferrous components include steel and cast iron, while examples of non-ferrous components include aluminum and copper.

I have experience with various software used in mechanical engineering design.

• AutoCAD for 2D drafting and modeling

• SolidWorks for 3D modeling and simulation

• CATIA for advanced surface modeling and analysis

• ANSYS for finite element analysis (FEA)

• MATLAB for mathematical modeling and simulation

• Creo Parametric for parametric modeling and assembly design

The maximum and minimum thickness for plastic parts depends on various factors such as material, design, and application.

• The maximum thickness is typically limited by the molding process and the material's ability to flow and cool properly.

• Thicker parts may require longer cooling times and can result in sink marks or warping.

• The minimum thickness is determined by the structural requirements and the material's ability to maintain its shape and strength.

• Thinner parts may be mor...read more

There are various types of mechanisms used in mechanical design. Some examples include gears, levers, pulleys, and linkages.

• Gears: used to transmit power and motion between rotating shafts

• Levers: used to amplify force or motion

• Pulleys: used to change the direction of force or transmit power

• Linkages: used to transmit motion or force between different parts of a machine

• Examples: bicycle gears, car transmission, crane pulleys, scissors, car suspension system

Solidworks 3D modeling basics include sketching, extruding, revolving, lofting, and filleting.

• Sketching: creating 2D profiles

• Extruding: pulling a sketch into a 3D shape

• Revolving: rotating a sketch around an axis to create a 3D shape

• Lofting: creating a shape by blending two or more profiles

• Filleting: rounding edges and corners

Stress is the force applied to a material, while strain is the resulting deformation. True position in GDT specifies the allowable deviation from the exact location of a feature. Tolerance stack up is the accumulation of variations in dimensions within an assembly.

• Stress is the internal resistance of a material to deformation under an applied force.

• Strain is the measure of deformation or displacement of material particles in response to stress.

• True position in GDT specifies t...read more

Different types of leaning techniques in machine learning

• Supervised learning

• Unsupervised learning

• Semi-supervised learning

• Reinforcement learning

• Transfer learning

• Deep learning

• Online learning

• Active learning

A robotic arm with 6 degrees of freedom for precise movements in multiple directions.

• Robotic arm with 6 degrees of freedom allows for movement in multiple directions

• Each joint of the arm provides a degree of freedom for precise control

• Commonly used in manufacturing, medical surgeries, and space exploration

Stress is the force applied to a material, while strain is the resulting deformation or change in shape.

• Stress is the internal resistance of a material to deformation under an applied force.

• Strain is the measure of deformation or change in shape of a material in response to stress.

• Stress is typically measured in units of force per unit area (such as Pascals), while strain is dimensionless.

• The relationship between stress and strain is described by the material's modulus of ela...read more