Medium Load Red Mould Compression Die Spring 8mm-50mm Outer Dia 20mm-300mm Long

Match the outer diameter (OD) to your die spring pocket bore — the OD should be 0.5–1 mm smaller than the pocket to allow free movement. The inner diameter (ID) should be at least 0.5–1 mm larger than your guide pin diameter. Check both dimensions in your tooling drawing before selecting a variant.

Red indicates a medium load class per ISO 10243 and JIS B 5012 international standards. Medium load springs offer a balanced spring rate — stronger than light load (yellow) but less stiff than heavy load (blue) or extra heavy (green). They are the most commonly used class in general injection mould and die stamping applications.

Load capacity varies by OD, ID, and free length. Larger OD and shorter free length generally produce higher spring rates. For specific load and deflection data for your chosen size, refer to the ISO 10243 standard tables or contact us with your size and required deflection force.

The red powder coating provides a degree of corrosion resistance suitable for typical indoor workshop and production environments. For applications involving coolant, cutting fluid, or high humidity, consider periodic inspection and replacement as part of your maintenance schedule.

Medium load die springs are typically rated for a maximum deflection of approximately 30–35% of free length for extended fatigue life. Compressing beyond this range significantly reduces cycle life. For intermittent use, up to 45% deflection may be acceptable. Consult the ISO 10243 deflection tables for your specific size.

Yes. These medium load red die springs are designed for exactly these applications — ejector plate return, stripper plate actuation, and punch press stripping. Ensure the spring pocket depth and guide pin length are correctly dimensioned to avoid coil bind at maximum compression.

The free length should be long enough so that at maximum compression the spring still exerts the required force, but short enough to fit within your pocket depth with adequate pre-load. A common approach: free length = pocket depth + required stroke + pre-compression allowance. If unsure, contact us with your pocket depth and required stroke.