TF/TL/TM/TH/TB Heavy Duty Load Compression Spring Die Springs O.D:8mm L:20-70mm

Match the load grade to the force your tooling requires at a given deflection. Yellow (Extra Light) suits light-duty stripping or ejection tasks with minimal force. Blue (Light) works for moderate ejection and clamping. Red (Medium) is the most common choice for general stamping and molding. Green (Heavy) is for high-force applications such as heavy blanking or large-area stripper plates. If you are unsure, calculate the required spring force from your tooling drawing and compare it to the spring's load-deflection curve for the selected length.

Die springs are typically rated for a maximum deflection of 25–30% of free length for dynamic (cyclic) applications and up to 40–45% for static applications. Exceeding the rated deflection significantly reduces fatigue life. Always design your tooling so the spring operates within the dynamic deflection limit for long service life. Refer to the specific load-deflection data for your chosen length and grade.

Yes. With an outer diameter of 8 mm, these springs fit standard 8 mm OD die spring pockets as defined by ISO 10243 and JIS B 5012. Verify that your pocket bore is sized to accept an 8 mm OD spring with appropriate clearance (typically 0.1–0.3 mm radial clearance on the OD). The inner diameter should also be checked against your guide pin diameter to ensure the spring seats correctly without binding.

These die springs are made from chromium-silicon (Cr-Si) alloy steel, which offers higher tensile strength, better fatigue resistance, and improved heat tolerance compared to standard carbon steel. The shot-peened surface further extends fatigue life by introducing compressive residual stress on the wire surface. This makes them suitable for high-cycle stamping and molding environments where standard springs would fail prematurely.

Yes. Die springs can be used in parallel (side by side in separate pockets) to multiply total force, or you can select a heavier load grade. Do not nest springs inside each other unless specifically designed for that configuration, as this can cause uneven loading and premature failure. When using multiple springs in a stripper plate, ensure all springs are the same grade and free length to distribute force evenly across the plate.

The free length should be chosen so that the spring operates within its recommended deflection range during the full stroke of your tooling. Measure the available pocket depth and the required working stroke. The free length should be at least: pocket depth + working stroke + a safety margin (typically 10–15% of free length). For example, if your pocket is 30 mm deep and your stroke is 8 mm, a 45–50 mm free length spring would be a reasonable starting point, keeping deflection within the dynamic limit.

Replace die springs if you notice a reduction in ejection or stripping force, visible cracking or corrosion on the spring body, a measurable reduction in free length (set loss greater than 3–5% of original free length), or after reaching the manufacturer's recommended cycle count for the deflection level used. Proactive replacement during scheduled tooling maintenance is recommended for high-volume production to avoid unplanned downtime.