Quality Diagnostics · D08
Open-frame warpage isn't a process failure - it's a green-body density gradient, amplified by geometry with no sidewall constraint.
Open-Frame Warpage
Symptom: U-channels, C-rings, open frames - intact through injection and debinding, then warp inward after sintering, always toward the gate side.
Root mechanism: during injection, the region farthest from the gate gets insufficient packing pressure, forming a low-density zone. During sintering, the shrinkage-rate mismatch between low- and high-density zones is fully released in an open structure with no sidewall constraint, producing warpage. This is a green-body density-distribution problem, not a sintering-process problem.
| Iteration | Approach | Yield |
|---|---|---|
| Round 1 | Single-side feed | 0% - severe warpage |
| Round 2 | Three-gate centripetal flow | 84% - warpage greatly reduced |
| Round 3 | Optimized three-face centripetal flow | 100% - flatness 0.019mm |