Understanding the Engineering Logic Behind the +10% / −5% Load Tolerance

Under GB/T 1972 and relevant international standards, disc spring load tolerances are designed to accommodate variations between theoretical calculations and actual performance. The asymmetric tolerance of +10% / −5% reflects practical engineering considerations.

1. The Difference Between Theory and Reality

The Almen–Laszlo (AL) formula is widely used to calculate disc spring loads. However, calculated values may differ from actual test results due to factors such as manufacturing fillets, changes in the effective lever arm, and friction between the spring and test plates. These factors can cause measured loads to exceed theoretical predictions.

2. Key Factors Affecting Load Tolerances

Manufacturing tolerances in height, thickness, inner diameter, and outer diameter influence spring performance. Their combined effects must be considered during tolerance design. Residual stresses and manufacturing processes may also affect the final load characteristics.

3. Why Use an Asymmetric Tolerance?

• +10% upper tolerance: Accommodates potential increases in measured load caused by manufacturing and testing conditions.

• −5% lower tolerance: Helps ensure that the spring maintains its minimum required load capacity.

This approach balances manufacturing realities with engineering performance requirements.

4. Raleigh Spring’s Quality Commitment

At Raleigh Spring, we follow applicable disc spring standards and focus on material consistency, process optimization, and comprehensive load testing. Our goal is not only to meet specified tolerances but also to achieve stable, consistent performance from batch to batch.

Reliable disc springs start with precise engineering and consistent quality control.