Three Profile Types for Three Access Scenarios
Clamping block profile selection is driven entirely by one question: can you access the clamping surface with a straight vertical force path? If yes, use flat. If no, determine whether the obstruction is lateral (gooseneck) or vertical (high-profile).
Profile Comparison
| Profile | Models | Geometry | Best For |
|---|---|---|---|
| Flat | Z1 (C45), Z2/Z3 (Al-Bronze) | Straight block, direct vertical clamping | Open-access workpieces, flat surfaces |
| Gooseneck | Z4 | Offset arm reaches around obstacles | Obstructed clamping points, stepped workpieces |
| High-profile | Z5 | Extended vertical reach | Deep cavities, tall workpieces, elevated clamping |
Selection Decision Tree
- Is the clamping surface directly accessible from above? → Yes: Flat (Z1/Z2/Z3). No: Continue.
- Is the obstruction lateral (beside the clamping point)? → Yes: Gooseneck (Z4) — the offset arm reaches around the obstruction.
- Is the obstruction vertical (clamping point is deep or elevated)? → Yes: High-profile (Z5) — the extended body reaches down or up to the clamping surface.
Material Selection Within Each Profile
After selecting the profile, choose the material:
- C45 steel (Z1): General-purpose. ~200 HB hardness. Cost-effective for most CNC fixture applications.
- Aluminum bronze 3.4365 (Z2/Z3): 5× higher thermal conductivity than steel. Use when clamping heat-sensitive workpieces (aluminum, thin-wall castings).
- Tool steel 1.2343 (Z6): Eccentric cam mechanism for rapid tightening. 40 HRC. Use for frequent changeover operations.
- Tool steel 1.2718 (Z7): Maximum clamping force. 52 HRC. Use for heavy-duty machining with high cutting forces.
Common Mistakes
- Using gooseneck where flat works: Gooseneck blocks have lower rigidity due to the offset arm. Don't use them when a flat block provides direct access — you lose clamping stiffness for no benefit.
- Undersizing the clamping force: The clamping block must resist at least 2× the maximum cutting force. Undersized clamps allow workpiece movement during aggressive cuts.
- Ignoring thermal effects: Steel clamps on aluminum workpieces can cause thermal distortion. Switch to aluminum bronze (Z2/Z3) for heat-sensitive applications.