FACTORS INFLUENCING QUALITY OF MOULDING

MATERIAL

MOULD

MACHINE

Characteristics of Polymer

Design factors in Part and; Mould

Specification to meet the requirement of Part and; Mould

• Molecular weight,
• MFI,
• pvT characteristics,
• Response to shear rate (Shear thinning) and limitation,
• Heat and Thermal stability,
• Shrinkage behaviour,
• Maximum flow ratio,
• Hygroscopic or not.

• Gate location, size and type,
• Sprue / runner size balanced type,
• Air vent,
• Wall thickness uniform and capable of promoting balancing of melt flow,
• Balancing of flow in un-symmetric part geometry,
• Mould release.

• Maximum shot capacity of plasticating unit,
• Residence time,
• Maximum injection rate,
• Number of stroke controlled steps for filling phase,
• Maximum injection pressure,
• Number of time controlled steps for pressure phase,
• Plasticating rate,
• Clamp force.