GD&T Tolerance Stack-up Analysis

Question 1

What is the primary purpose of tolerance stack-up analysis in GD&T?

Accepted Answer

To determine the worst-case variation in an assembly due to accumulated tolerances

Answer

To minimize the number of dimensions on a drawing

Answer

To select the most economical manufacturing process

Answer

To calculate surface finish requirements

Question 2

In a worst-case tolerance stack-up, how are individual tolerances combined?

Accepted Answer

They are arithmetically added, assuming all tolerances at their maximum

Answer

They are multiplied together

Answer

They are statistically averaged using root sum square

Answer

They are subtracted from the nominal dimension

Question 3

What does RSS (Root Sum Square) analysis assume about the distribution of actual part dimensions?

Accepted Answer

Parts follow a normal (Gaussian) distribution

Answer

All parts are at the maximum tolerance limit

Answer

Parts follow a uniform distribution

Answer

Parts are always at the nominal dimension

Question 4

Which type of tolerance stack-up analysis is more conservative and results in a larger required total tolerance?

Accepted Answer

Worst-case (arithmetic) analysis

Answer

Root Sum Square (RSS) analysis

Answer

Statistical analysis

Answer

Monte Carlo simulation

Question 5

In a linear worst-case tolerance stack-up, what is the total gap variation if three dimensions each have a bilateral tolerance of ±0.1 mm?

Accepted Answer

±0.3 mm

Answer

±0.1 mm

Answer

±0.2 mm

Answer

±0.6 mm

Question 6

What is a 'loop diagram' used for in tolerance stack-up analysis?

Accepted Answer

To identify which dimensions contribute to a critical assembly gap or interference

Answer

To show the manufacturing process flow

Answer

To display GD&T symbols graphically

Answer

To document inspection measurement results

Question 7

When should tolerance stack-up analysis be performed during product development?

Accepted Answer

Early in the design phase before drawings are released

Answer

Only after manufacturing defects are found during production

Answer

During final inspection before shipment to the customer

Answer

Only when assembled parts fail to meet functional requirements