Round Wire Coil Springs - 75% Deflection, WY Series

This round-wire coil spring is used inside injection-molded assemblies where a controlled compression force is required over a defined travel. A typical use case is automotive and industrial connectors, where the spring must maintain predictable load response despite tolerance stack-up during engagement and latching.

Another common application is medical and lab device mechanisms (e.g., cartridge retention, hinged closures, or actuator returns). The 75% deflection design supports repeatable force levels at higher deflection ratios, helping reduce variation in feel and actuation performance.

It is also suited for consumer electronics and office equipment snap-fit mechanisms, where compact space is limited. With an outer diameter range of 3–16 mm and length 5–70 mm, engineers can select a matching size to achieve the targeted spring constant and maximum load without redesigning the housing geometry.

• 75% allowable deflection ratio supports controlled spring response at higher travel
• WY geometry helps maintain stable characteristics in dynamic assembly conditions

The provided metadata does not specify the steel grade, heat-treatment condition, or hardness (HRC) for this WY series spring. Because coil-spring performance (fatigue life, wear resistance, and load stability) is strongly tied to the material grade and tempering process, exact comparisons to steels (e.g., SKH51/AISI M2 or SKD61/H13 equivalents) cannot be confirmed from the supplied information.

For engineering selection, treat the spring as a finished spring product where the manufacturer’s wire material, forming method, and tempering are already optimized to meet the stated spring constant and maximum load ranges. If fatigue life or repeated cycling is a critical requirement, request the material specification and heat-treatment/hardness data to confirm toughness vs. wear/fatigue trade-offs.

• Material grade and heat treatment: not provided in this dataset
• Hardness (HRC): not provided
• Performance alignment: use provided k (0.1, 0.2 N/mm) and max load (0.38–10.3 N) for sizing

To select the correct spring, start with the required force at the operating travel and confirm it fits within your available envelope. This WY series is specified for an allowable deflection ratio of 75%, meaning you should plan the working deflection so the spring operates within that limit to maintain the intended response.

Next, match the mechanical requirements using the available spring constant and loading capability. Choose between spring constant k = 0.1 or 0.2 N/mm and verify the expected load level falls within the provided maximum load of 0.38–10.3 N.

• Outer diameter D: select within 3–16 mm to clear the guide and housing walls
• Free length L: select within 5–70 mm based on the available stack height in the mold tool/assembly

Finally, account for fitment and tolerance stack-up: the D dimension should consider clearance to avoid binding, while L must accommodate installed length after compression. If you are close to bounds, select the next compatible size and re-check force vs. travel to keep operation under the 75% deflection limit.