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When standard springs fail under repeated cycling or heavy loads, engineers and toolmakers reach for a dedicated die spring. Whether you are building a stamping die, injection mold, or industrial fixture, these heavy load compression die springs deliver consistent, repeatable force without premature fatigue — saving you costly downtime and rework.
Each spring is manufactured from rectangular-section chromium-silicon alloy steel wire, wound to tight tolerances and finished with a color-coded red coating that identifies the heavy load rating at a glance. Outer diameters span Φ8 mm (0.31 in) to Φ50 mm (1.97 in), with inner diameters sized at approximately 50% of OD for standard shaft compatibility. Free lengths range from 20 mm (0.79 in) up to 300 mm (11.81 in), covering a wide spectrum of travel requirements.
Typical use cases include precision stamping and blanking dies where consistent spring-back force is critical, injection mold ejector systems requiring long service life under cyclic compression, and heavy-duty industrial jigs and fixtures where standard coil springs lack the load capacity for reliable clamping or return force.
Red color-coded per ISO/JIS standard, indicating the highest load class for maximum force output per unit deflection.
Flat-wound wire maximizes material contact area, delivering higher load capacity and greater fatigue life compared to round-wire springs of the same envelope.
Outer diameters from Φ8 mm to Φ50 mm and free lengths from 20 mm to 300 mm — one product line covers most tooling and fixture requirements.
Cr-Si alloy wire provides superior tensile strength and heat resistance, maintaining spring rate stability across extended production runs.
Precision-wound to consistent OD, ID, and free-length tolerances, ensuring drop-in replacement compatibility with existing die sets and mold bases.
Engineered for high-cycle applications — suitable for stamping and molding operations where springs are compressed thousands of times per shift.
| Spring Type | Heavy Load Compression Die Spring |
|---|---|
| Load Class | Heavy (Red) |
| Material | Chromium-Silicon Alloy Steel (Cr-Si) |
| Wire Section | Rectangular (flat-wound) |
| Surface Finish | Red epoxy coating |
| Outer Diameter (OD) | Φ8 mm – Φ50 mm (0.31 in – 1.97 in) |
| Inner Diameter (ID) | See variant options |
| Free Length | 20 mm – 300 mm (0.79 in – 11.81 in) |
| Standard Reference | ISO 10243 / JIS B 5012 |
| Ends | Closed and ground |
| Deflection Rate | See variant options |
| Max Deflection | See variant options |
Match the inner diameter (ID) to your guide shaft diameter, leaving 0.5–1 mm clearance. Then confirm the outer diameter (OD) fits within your die pocket or spring housing. All variants on this listing follow an approximately 2:1 OD-to-ID ratio, which aligns with standard ISO/JIS die spring shaft sizing.
Red identifies the Heavy Load class per ISO 10243 and JIS B 5012 standards. This is the highest standard load rating, providing the greatest force per millimeter of deflection. If your application requires lighter force, consider Light (yellow), Medium (blue), or Extra Heavy (brown) rated springs instead.
Die springs use rectangular-section wire, which allows more material to be packed into the same envelope as a round-wire spring. This results in significantly higher load capacity — typically 30–50% more force for the same OD and free length — along with better fatigue resistance under cyclic loading.
The red epoxy coating provides a degree of surface protection against light moisture and handling. However, these springs are not rated for continuous immersion or highly corrosive environments. For wet or chemical-exposure applications, consider stainless steel springs or apply additional protective coatings.
These springs are designed for stamping dies, blanking dies, injection mold ejector systems, forming tools, industrial jigs, and heavy-duty fixture clamps. They are compatible with standard ISO 10243 and JIS B 5012 die sets. Always verify OD, ID, and free length against your specific tooling drawings before ordering.
Select a free length that gives you the required working stroke plus a safety margin. As a general rule, do not compress a die spring beyond 30% of its free length for heavy load class springs to maintain fatigue life. For example, if you need 15 mm of travel, choose a free length of at least 50 mm. Refer to the spring rate data for your specific variant to calculate exact deflection force.
Yes, provided the OD, ID, and free length match your existing spring specifications and the load class (heavy/red) is the same. These springs conform to ISO 10243 / JIS B 5012 dimensional standards, making them compatible with most standard die sets and mold bases from major tooling suppliers.
