Common Injection Molding Defects
Injection molding defects can affect part appearance, function, and cost. Understanding root causes enables quick troubleshooting and prevention.
1. Sink Marks
登場： Depressions on part surface, typically near thick sections.
Causes:
- Excessive wall thickness variation
- Ribs too thick relative to wall
- Insufficient cooling time
- High packing pressure needed
Solutions:
- Reduce rib thickness to 50-70% of wall
- Increase cooling time
- Optimize packing pressure and time
- Use gas-assist molding for thick sections
2. Flash
登場： Thin excess plastic at parting lines or around features.
Causes:
- Insufficient clamp force
- Worn mold components
- Excessive injection pressure
- Poor mold alignment
Solutions:
- Increase clamp tonnage
- Repair or replace worn components
- Reduce injection pressure
- Check mold alignment and guide pins
3. Short Shots
4. Warpage
登場： Part distortion after ejection.
Causes:
- Non-uniform cooling
- Asymmetric part design
- Incorrect ejection timing
- Material shrinkage variation
Solutions:
- Optimize cooling channel design
- Balance wall thickness
- Adjust ejection timing
- Use material with lower shrinkage
5. Weld Lines
登場： Visible lines where flow fronts meet.
Causes:
- Multiple gates or flow fronts
- Holes or inserts creating flow splits
- Low injection speed
- Cold material at meeting point
Solutions:
- Move weld lines to non-critical areas
- Increase injection speed
- Raise mold temperature
- Add overflow wells at weld locations
Defect Prevention Checklist
- Design parts with uniform wall thickness
- Include adequate draft angles
- Provide proper venting
- Optimize gate location
- Ensure balanced cooling
結論
Most injection molding defects stem from design, processing, or mold issues. Early detection and systematic troubleshooting minimize production downtime and scrap rates.
関連リソース
- エンジニアリングプラスチックのコスト要因
- PEEKとPEIの比較
- Flame Retardant Plastics
- Food Grade Plastics Guide
- Nylon Moisture Treatment
関連リソース
- エンジニアリングプラスチックのコスト要因
- PEEKとPEIの比較
- Flame Retardant Plastics
- Food Grade Plastics Guide
- Nylon Moisture Treatment
関連リソース
- エンジニアリングプラスチックのコスト要因
- PEEKとPEIの比較
- Flame Retardant Plastics
- Food Grade Plastics Guide
- Nylon Moisture Treatment
よくあるご質問
When does Plastic Injection Molding Defects — Causes and Solutions make sense?
Plastic Injection Molding Defects — Causes and Solutions makes sense when the part volume, material choice, geometry, and repeatability needs justify mold design and tooling investment.
What design factors matter most for Plastic Injection Molding Defects — Causes and Solutions?
肉厚、リブ、ボス、抜き勾配、ゲート位置、収縮、パーティングライン、およびエジェクションは、いずれも成形品の品質に影響を与えます。.
金型製作の前に、どのような情報が必要ですか？
サプライヤーは、3Dモデル、材質、予想年間生産数量、外観要件、公差要件、および組み立てや機能試験に関する要件を確認する必要があります。.
What is the biggest risk in Plastic Injection Molding Defects — Causes and Solutions?
最大のリスクは、実際の用途において、材料の挙動、収縮、流動性、および部品の機能が十分に確認される前に、金型を承認してしまうことです。.
