WT Series Round Wire Coil Springs 40% Deflection

These round wire coil springs are used as precision return and shock-absorption elements inside injection mold tooling where stable compliance is needed. The 40% deflection design helps maintain consistent force response as actuating components move, supporting repeatable operation cycle after cycle.

• Automotive connector and latch mechanisms: Fit the spring in spring-loaded ejector or latch subassemblies to damp vibration and return reliably after short stroke actuation, using the predictable 40% deflection behavior.
• Medical device housing molds: Apply in retract/return mechanisms for small core pulls or runner-related moving parts, where controlled load support reduces the risk of bounce and improves dimensional repeatability.
• General industrial automation tooling: Use for resilient stops or force-limiting fixtures; the piano wire construction supports high strength needed to sustain load support under varying duty.

The WT series springs are manufactured from piano wire, a high-carbon steel known for high tensile strength and excellent fatigue performance—ideal for maintaining stable spring force under cyclic loading. Piano wire is typically produced via controlled cold working to achieve the required round-wire geometry and consistent spring response.

• Heat treatment: Springs are commonly supplied in a pre-formed, hardened condition suitable for load support; exact heat-treatment state is not specified in the provided data.
• Performance trade-off: High strength and wear/fatigue resistance improve load stability, while toughness must be managed through proper forming and controlled stresses to avoid premature microcracking.
• Available variants: This listing focuses on deflection ratio variants (40% and also 35% noted), enabling tuning of compliance versus load capacity without changing the core piano-wire material approach.

For wear-intensive environments, consider corrosion control and proper spring seating surfaces in the tooling design to preserve fatigue life.

Select the spring by matching deflection ratio, load requirement, and geometry to your mold’s mechanism stroke and force envelope. Start with the required deflection ratio: this variant is specified at 40% allowable deflection ratio.

• Determine required stroke: For a target working displacement, ensure the expected deflection falls within the chosen ratio (40% for this WT configuration; 35% is available per provided specs).
• Match length L (mm): Choose the installed free/working length within 5 to 80 mm, accounting for how the spring seats in the mold (end compression and guide constraints).
• Match outer diameter D (mm): Select D = 3 to 27 mm so the spring clears surrounding components and fits within the spring pocket while preventing side loading.
• Verify spring constant (N/mm): Use the provided spring constant options 1.5, 2.0, 3.9 N/mm to meet your force/deflection target; confirm the resulting load stays below the maximum load 2.9 ~ 125.5 N for your chosen size.

Because exact tolerance values are not provided, maintain design clearance and ensure the spring seats squarely to limit stress concentration and fit-induced binding.