Causes of Silver Streaks in Injection Molding

1. Phenomenon

A phenomenon in which silver streaks occur on the surface of a molded product.

2. Cause

• Poor air release (gas release)
• Overly small gates, runners, and sprues
• Insufficient degassing of the mold
• Small slug well
• A lot of water adsorbed on the resin
• Insufficient injection pressure
• Overly low mold temperature
• High cylinder temperature

• Fast injection speed

3. Measures

• Create a gas vent
• Increase the size of gate, runner, and sprue
• Degas the mold
• Enlarge the slug well
• Fully pre-dry
• Increase injection pressure
• Increase mold temperature
• Lower cylinder temperature
• Slow the injection speed
• Degas the runner end just below the sprue before entering the product.