GD&T Tolerance Stack-up Analysis 3

Question 1

What is the correct formula for RSS (Root Sum Square) tolerance analysis?

Accepted Answer

T_total = √(T1² + T2² + T3² + ... + Tn²)

Answer

RSS combines tolerances by squaring each, summing all the squares, and taking the square root, yielding a smaller combined tolerance than simple arithmetic addition.

Question 2

A three-part assembly has dimension tolerances of ±0.2 mm, ±0.3 mm, and ±0.1 mm. What is the RSS total tolerance?

Accepted Answer

±0.374 mm

Answer

RSS calculation: √(0.2² + 0.3² + 0.1²) = √(0.04 + 0.09 + 0.01) = √0.14 ≈ ±0.374 mm.

Question 3

What does a 'sensitivity factor' (influence coefficient) represent in an advanced tolerance stack-up analysis?

Accepted Answer

A multiplier indicating how a dimension's variation influences the assembly gap output

Answer

Sensitivity factors indicate how a unit change in a contributing dimension affects the output gap; they are +1 or -1 for simple linear stacks but can differ for angular or complex geometric relationships.

Question 4

Which key benefit does tolerance stack-up analysis provide for manufacturing cost optimization?

Accepted Answer

It identifies which tolerances can be relaxed without affecting functional assembly requirements

Answer

Stack-up analysis identifies which tolerances most significantly affect assembly function, allowing engineers to selectively relax less critical tolerances to reduce manufacturing costs.

Question 5

In a correctly constructed loop diagram for stack-up analysis, the dimension chain must form a closed loop. What does successful closure of the loop indicate?

Accepted Answer

All contributing dimensions have been identified and the loop is complete for analysis

Answer

In a correctly set up loop diagram, the dimension chain must close back on the starting point, confirming that all contributing dimensions have been identified and the analysis is complete.

(GD&T) Geometric Dimensioning and Tolerancing Certification Practice Test

(GD&T) Geometric Dimensioning and Tolerancing Certification Practice Test

GD&T Tolerance Stack-up Analysis 3