What Is the Difference Between Single Flange and Double Flange Tension Link Retainers
Key Takeaway: Single flange retainers are sufficient for standard plate weights (≤200 kg) and moderate cycle rates. Double flange retainers are needed when plate weight exceeds 200 kg, opening acceleration is high, or when bolt pull-through resistance is critical. The double flange distributes end-of-stroke force over 2× the contact area.
Structural Difference
Both retainer types mount to the mold plate and hold the tension link bolt in position. The key difference is the number of bearing surfaces:
| Feature | Single Flange | Double Flange |
|---|---|---|
| Bearing surfaces | 1 flange | 2 flanges |
| Force distribution area | 1× contact area | 2× contact area |
| Pull-through resistance | Standard | 2× standard |
| Plate deformation risk | Higher (concentrated force) | Lower (distributed force) |
| Installation complexity | Simple (single counterbore) | Moderate (double counterbore) |
| Cost | $ | $$ |
When to Choose Each
- Single flange: Plate weight ≤200 kg per side, cycle rate ≤20 cpm, standard opening speed. Covers 80% of applications.
- Double flange: Plate weight >200 kg, cycle rate >20 cpm, high-acceleration opening (servo-driven presses), or when bolt pull-through has been observed with single flange retainers.
The double flange design is particularly important on molds with high-speed injection molding machines where opening acceleration can exceed 1 g, creating impact forces much larger than the static plate weight.
Frequently Asked Questions
What happens if I use single flange retainers on a heavy mold?+
The concentrated end-of-stroke force can deform the plate mounting surface (mushrooming), create bolt pull-through risk, and accelerate retainer wear. Switch to double flange when plate weight exceeds 200 kg per side.
Are single and double flange retainers interchangeable?+
Not directly — double flange requires a different (deeper) counterbore in the plate. However, upgrading from single to double is possible by deepening the existing counterbore. Check the dimensional drawing for required bore dimensions.
Can I mix single and double flange retainers in the same mold?+
Yes, if different parting lines have different load requirements. Use double flange on the heavier parting line and single on the lighter one. Do not mix on the same parting line.