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Molding Characteristics / Mold Shrinkage

Contents Introduction Safety Molding Machines Molding Conditions Recycling
Molding Characteristics Product Design Mold Design Countermeasures for Defects

Flow Characteristics  Mold Shrinkage  After-shrinkage / Absorptional Change  Thermal Stability

List of DURACON® POM grades This page's PDF(0.97MB)

6. Molding Characteristics

6.2 Mold Shrinkage


Fig. 6-5 Mold shrinkage of M90-44 (side gate)

Fig. 6-6 Mold shrinkage of M90-44 (pin gate)
 Molding conditions:
  Injection pressure: 50MPa
  Cylinder temp.: 190°C
  Mold temp.: 80°C
  Injection speed: 50mm/s
  Mold: 80×80mm flat plate
 Molding conditions:
  Cylinder temp.: 190°C
  Mold temp.: 80°C
  Injection speed: 17mm/s
  Mold: 50×50mm flat plate
  Pin gate: 1.0mm dia.

 

Table 6-1 Relation of molding conditions and mold shrinkage

  Change Mold shrinkage After-shrinkage
Walk thickness ↑ Thick ↑ Large ↓ Small
Gate size ↑ Large ↓ Small  
Mold temperature ↑ High ↑ Large ↓ Small
Material temperature ↑ High ↑ Large  
Holding pressure ↑ High ↓ Small  

 


Fig. 6-7 Relationship between injection
pressure and mold shrinkage

Fig. 6-8 Relationship between material
temperature and mold shrinkage

Fig. 6-9 Relationship between mold
temperature and mold shrinkage
 

 


Flow Characteristics  Mold Shrinkage  After-shrinkage / Absorptional Change  Thermal Stability

Contents Introduction Safety Molding Machines Molding Conditions Recycling
Molding Characteristics Product Design Mold Design Countermeasures for Defects