Locking Blocks
Precision locking blocks to absorb injection pressure and secure slides.
Locking Block Variants Comparison
Locking blocks (heel blocks) absorb the immense injection pressure acting against the slide core. Selecting the right variant is critical to prevent mold flashing.
| Feature | Standard Solid Blocks | Angular Hole Blocks | Adjustable Wedge Blocks |
|---|---|---|---|
| Design Structure | Solid hardened steel (SKD11 / H13) | Includes pre-machined angled pin hole | Includes shims or adjustable wedges |
| Space Efficiency | Medium | High (combines pin & heel) | Low (requires more cavity space) |
| Wear Compensation | None (must replace or weld) | None | High (adjust shims to restore preload) |
| Installation Time | Fast | Very Fast | Slow (requires tuning) |
| Best For | Standard slide cores | Compact molds | High-volume / abrasive resins |
Force Analysis & Kinematics
Injection Pressure Resistance
During the holding phase, injection pressures of 400-1000 bar act directly on the projected area of the slide core. The locking block must resist this entirely via its wedge interface. If the block deforms by even 0.02mm, the part will flash. Hardness is critical: blocks must be hardened to HRC 55-60 to resist compressive yielding.
Wedge Angle Differential
The locking wedge angle (typically 15° to 25°) must be 2° to 3° greater than the angled pin angle. If the angles are identical, the angled pin will try to pull the slide backward while the locking block is still engaged, causing catastrophic mold damage.
Application Scenarios
High-Pressure Injection
Molding polycarbonate (PC) or PEEK requires massive holding pressures. Solid blocks without holes maintain maximum structural rigidity.
High-Wear / Million-Cycle Molds
Over time, the wedge surface wears, causing flash. Instead of replacing the block, adjusting the preload saves maintenance time.
Technical Resources
Need a Custom Quote?
Send your specifications and receive a quote. MOQ: 1 piece. Custom dimensions available.