A manufacturable compression spring request connects the available package space with measurable force targets. Free length and outside diameter alone rarely define stable performance.
Define the working window
List free, installed, minimum working and limit heights, with the required load at each useful position. Two working load points define rate more clearly than a single force value.
Check clearance and solid-height margin
Hole-guided springs need outside-diameter clearance for tolerance and movement. Rod-guided springs need inside-diameter clearance for assembly and friction. Avoid making the minimum working height equal to theoretical solid height.
Ends change active coils
Open, closed and ground ends affect support, total coils, active coils and cost. Select the end configuration together with the mounting method.
What to validate on samples
Measure free length, squareness, load at specified heights and recovery after compression. High-cycle applications also need testing in a representative fixture, frequency and stroke.
References
This article is informed by public standards catalogues and industry engineering resources. Project values should be confirmed by drawings, material certificates and sample validation.