Common Problems In The Injection Molding Process

Common problems in the injection molding process

1. Molding problem: surface fogging

Cause analysis: water vapor or contaminants in the material; using too high a release agent; too high injection speed

Improvement method: materials-avoid mixing of contaminated raw materials or recycled materials

Injection molding machine-clean the silo of the injection molding machine before use; fully empty the material in the barrel

Process: appropriately reduce the injection speed and increase the injection pressure; increase the injection temperature and back pressure; fully dry the raw materials; avoid using too much release agent

2. Molding problem: fingerprint printing (also known as ripple, vibration pattern)

Causes: high material viscosity; too low injection and mold temperature; too low injection pressure; difficult scheduling; too small runner or gate

Improvement method: material: improve material fluidity

Mold design: reasonably set up exhaust groove; increase gate and runner size; set up sufficiently large cold slug well; polish runner

Process conditions: increase the temperature of the barrel and the mold; increase the injection speed; increase the injection pressure

3. Forming problem: burr

Causes: insufficient clamping force; unreasonable or deformed mold exhaust design; excessive molding temperature or injection pressure; excessive melt volume during injection

Improvement method: mold design: reasonably design the mold to ensure that the mold can be closed tightly; clean the mold surface; reasonably design the depth of the exhaust groove

Injection molding machine: set a proper clamping force or replace with a larger injection molding machine

Process conditions: reduce the temperature of the barrel and the mold; increase the injection time and reduce the injection speed; reduce the injection and holding pressure; reduce the injection volume