As key elastic components in molds, mold springs feature a compact installation volume, excellent elasticity, high stiffness, high precision, and long fatigue life. A detailed analysis is provided below:
Structural Characteristics: High Strength and Space Optimization
Rectangular Cross-Section Design
Mold springs are typically wound with rectangular-section steel wire. Compared to round wire springs, they offer a higher spring constant and stiffness within the same space. For example, a 20mm Φ rectangular spring can generate 30% more force when compressed than a round wire spring of the same diameter, making it suitable for high-load applications.
Compact Structure
Outer diameters range from Φ6mm to Φ50mm, with fine length steps (5mm increments for 15-80mm, 10mm increments for 80-100mm, and 25mm increments for ≥100mm), making them suitable for use in confined spaces within molds. For example, in precision electronic molds, a Φ10mm x 30mm micro spring can consistently deliver 500N of force.
Performance Grading: Precisely Matching Load Requirements
Color-Coded Load System
Five load types are distinguished by color for quick selection:
Yellow (TF): Light load, maximum compression ratio of 58% (300,000 cycles life), suitable for low-force applications such as ejector pins.
Blue (TL): Light load, compression ratio of 48%, suitable for medium-force applications such as press plates.
Red (TM): Medium load, compression ratio of 38%, commonly used in stripper plates for composite dies.
Green (TH): Heavy load, compression ratio of 28%, widely used in punching and forming dies.
Brown (TB): Extremely heavy load, compression ratio of 24%, suitable for large die-casting molds.
Life and Compression Ratio Balance
Compression is inversely proportional to life: For a 30mm Φ green spring, for example, a maximum compression of 12mm (24%) at 300,000 cycles would reduce life to 100,000 cycles if compressed to 15mm (30%). During design, the compression ratio should be selected based on the production batch size. For example, for mass production molds, a compression ratio with a lifespan of 500,000 cycles (e.g., a 24% compression ratio for a green spring) is preferred.
Functional Diversity: Covering the Entire Mold Process
Power Transmission and Adjustment
Opening and Closing Force Control: Adjusting the spring compression adjusts the mold opening and closing force. For example, in automotive panel molds, a brown spring (TB) provides a closing force of 2000N, ensuring stable molding of large parts.
Rebound Speed Optimization: Spring rebound force affects product demolding efficiency. In high-speed stamping lines, the rapid rebound of a blue spring (TL) can increase production cycles to 300 cycles/minute.
Stability Guarantee
Pressure Balance: In injection molds, a green spring (TH) provides a uniformly distributed sealing pressure of 1000N/cm², preventing molten plastic from leaking.
Vibration Absorption: Nitrogen gas springs (a new elastic component) absorb impact energy during mold closing, reducing platen deformation and extending mold life by over 30%.
Precise Gap Adjustment
Finely adjust mold gaps by adjusting spring compression. For example, in precision connector molds, the compression tolerance of the Red Spring (TM) is controlled within ±0.1mm, ensuring a product dimensional tolerance of ±0.02mm.
Materials and Processing: Durability Guarantee
Chromium Alloy Steel
Used from high-temperature-resistant (operating temperature ≤ 200°C) and highly rigid chromium alloy steel, after heat treatment (quenching followed by medium-temperature tempering), the surface hardness reaches HRC 48-52, improving fatigue resistance by 50%.
Surface Treatment Technology
Shot Peening: Shot peening is performed on springs subjected to variable loads to create a compressive stress layer on the surface, extending fatigue life by 2-3 times.
