Materials/Function
What is the primary function of steel in the automotive industry?
To give strength and support to car parts.
What does a bolt or screw do in an assembly?
It holds parts together.
What is a tolerance in manufacturing?
A tolerance is the acceptable range of variation in a part’s dimensions.
What is a scratch defect in manufacturing?
An abrasion on the surface from rough contact.
How can you fix a misaligned part?
Adjust it or use a thin piece of material to fill the gap.
Which material is best for parts needing high heat resistance and low weight?
Titanium or ceramics
How does the shape of a gear help it work?
It transfers motion and force.
Why are tolerances important for a hydraulic cylinder?
So it fits well and doesn’t leak.
What causes warping in molded plastic?
Uneven or fast cooling.
What should you do if a part shows rust?
Clean it and add protection like paint or coating.
What makes aluminum a good choice for aircraft parts?
It’s strong, light, and doesn’t rust easily.
Why do airplanes use rivets instead of welds?
Rivets are light and reliable.
How do tight tolerances (e.g., ±0.01 mm) affect the cost and production speed of a mechanical part?
They raise cost and slow production due to high precision.
What defect does gas entrapment cause in casting?
Porosity — small air holes inside the part.
How can you fix warping in a welded metal part?
Use slow or controlled cooling methods.
Why is stainless steel better than carbon steel for food equipment?
It resists rust and is safe and clean for food use.
What is the purpose of a keyway in a shaft?
It stops the part from rotating freely.
When is a loose tolerance acceptable?
When the part isn’t under stress or is not critical.
Why might a part crack after heat treatment?
Uneven cooling or fast temperature change causes stress.
How can you stop cracks from fatigue in future parts?
Use better materials and improve the part’s shape.
How do fatigue and thermal cycling affect parts in aerospace engines?
Repeated stress and temperature changes can cause cracks and weaken the part.
In a plane wing, why must the spar be well connected to the ribs?
To keep the wing strong and stable in flight.
How do geometric dimensioning and tolerancing (GD&T) principles help in multi-part assemblies?
It ensures proper fit and function, even with small part differences.
What’s the difference between adhesion and cohesion failure in composites?
Adhesion is between materials; cohesion is inside the material. Both weaken the part.
How can you solve a size mismatch in critical parts that can’t be re-machined?
Use flexible fittings or tolerance rings to adjust the fit.