der pPer standard ISO4427, if fabricate with pipes, there is a 50% pressure derating for fabricated tees.
It’s important to confirm with end customer’s pipe operation pressure and the design safety ratio. Then to select the right solution for the customer. 
Why is Injection Moulding is not recommended for Large-Diameter Pipe Fittings?
1. Flow Path and Void Defects (Core Issue)
During injection moulding of large components, molten plastic must flow over long distances, leading to:
Incomplete Filling: Premature cooling prevents full mold cavity filling.
Voids/Porosity: Internal defects caused by uneven shrinkage or poor venting, significantly reducing pressure resistance and structural strength.
Weld Lines: Weak molecular bonding at multi-gate junctions, creating fracture risks (especially dangerous with lateral finger gates).
2. Gate Design Risks (Lateral Finger Gate)
While lateral finger gates improve flow, they pose critical issues in large parts:
High Residual Stress: Concentrated near gates, leading to warping or cracking.
Leakage in Sealing Surfaces: Weld lines on flange connections may fail under high pressure.
3. Equipment and Cost Limitations
Large pipe fittings require:
Massive Molds & High Clamping Force (1,000+ ton injection machines), resulting in prohibitive tooling costs.
Low Yield Rates: Defects increase scrap rates, making alternative processes (e.g., extrusion, rotomoulding) more cost-effective.
Please contact with Smart Joint, we can offer you a comprehensive PE pipe joint solution with non-pressure derating up to 2250mm.
