The Leader Pin Selection Framework
Leader pin selection follows a three-step process:
Step 1: Count Your Plates
Two-plate mold → Straight leader pins. Three-plate mold → Stepped leader pins (one step aligns the main halves, the other aligns the runner plate). Stack mold → Two-step leader pins.
Step 2: Check Your Environment
Standard shop → Standard SUJ2 pins with grease. Cleanroom (ISO 7+) → Oil-free pins. Food packaging (FDA) → Oil-free pins. Medical devices → Oil-free pins.
Step 3: Check Your Plate Size
Plate width/length < 500 mm → Main leaders only. Plate > 500 mm with tight tolerance → Add guiding assist pins at four corners.
Decision Matrix
| Mold Type | Recommended Pin | Material |
|---|---|---|
| Standard 2-plate | Straight | SUJ2 (HRC 58-62) |
| 3-plate | Stepped (1-step) | SUJ2 |
| Stack mold | Stepped (2-step) | SUJ2 |
| Cleanroom / FDA | Oil-free | Bronze + PTFE |
| Large plate (>500mm) | Straight + Guiding Assist | SUJ2 |