OD 27mm/ID 13.5mm Springs Compression Mould Spring Light/Medium/Heavy Load Duty

Select the load grade based on the force required at your working deflection. Yellow (Light) suits low-force ejector returns and light stripper plates. Blue (Medium) covers general-purpose mould and press tooling. Red (Heavy), Green (Extra Heavy), and Brown (Super Heavy) are for high-tonnage dies and heavy-duty automation fixtures. If you know your required spring force and stroke, calculate the needed spring rate (Force ÷ Deflection) and match it to the grade chart for this OD/ID combination.

Measure your mould pocket depth (the maximum space available when the mould is fully open) — this is your maximum free length. Then confirm that the compressed length at full stroke still leaves the spring with some remaining travel (typically 15–20% of free length as a safety margin). Choose the free length option closest to your pocket depth from the 25 mm–300 mm range available.

Yes. The 13.5 mm inner diameter accommodates guide rods up to approximately 13 mm in diameter, leaving a small clearance for smooth sliding without binding. Using a guide rod is recommended for longer springs (100 mm+) to prevent lateral buckling under load.

The springs carry a surface treatment that provides resistance to workshop humidity and light coolant splash typical of mould and press environments. For continuous immersion or aggressive chemical exposure, additional protective measures (such as periodic lubrication or a protective coating) are advisable. Contact us to confirm the specific surface treatment for your chosen variant.

Rectangular (flat) wire coils have a higher fill factor — more metal cross-section per unit of spring length — which translates to a higher spring rate and greater load capacity for the same outer diameter and free length. This makes them the standard choice for mould and die applications where space is constrained but force requirements are significant.

Yes. Springs arranged in parallel (side by side, sharing the same deflection) have their spring rates added together. For example, two identical Medium-grade springs in parallel will deliver twice the force at the same stroke. Ensure your mould pocket or fixture has sufficient space for the additional springs and that all springs are the same free length and grade to share load evenly.

Mould springs (also called die springs) are manufactured to tighter dimensional tolerances, use rectangular wire for higher load density, and are rated for millions of cycles under controlled deflection. Standard hardware springs use round wire, have looser tolerances, and are not rated for high-cycle industrial use. For mould, press, and automation applications requiring repeatable performance, mould springs are the correct choice.