Silver Streaks – What, Why and Remedies?
Shibaura Machine India successfully conducted a webinar focusing on one of the
most prevalent quality issues in the injection molding industry – Silver Streaks. This session aimed to provide actionable insights and solutions for addressing this common defect in injection-molded components
Key Details:
Webinar Topic: Silver Streaks – What, Why and Remedies?
Date: 31/12/24
Duration: 1 Hour
Webinar Highlights
Understanding Silver Streaks
as silver or discoloration streaks and are primarily caused by:
- Moisture in Polymer
- High Melt Temperature
Causes and Remedies Discussed
Moisture Streaks
Cause:
Absorption of moisture by hygroscopic polymers, which turns into
steam during molding.
Remedy:
o Pre-dry raw materials as per manufacturer guidelines.
o Monitor moisture content post-drying.
o Use dehumidified dryers for sensitive materials.
High Melt Temperature Streaks
Cause:
Excessive heat leading to degradation of the polymer.
Remedy:
o Optimize barrel temperature and screw speed.
o Adjust back pressure and residence time of polymer.
o Avoid high injection speeds and excessive nozzle temperatures.
Mould and Process Contributions
Increases the risk of streaks.
Cause frictional heat buildup, contributing to defects.
Ensure balanced mold temperature and gate dimensions to reduce friction.
Causes and Remedies Discussed
Audience Interaction
Participants actively engaged in the live Q&A session, where real-world case studies and troubleshooting tips were discussed. Attendees commended the technical depth and practical approach to solving production challenges.
Key Takeaways
- Proper material handling and pre-drying are critical to minimizing defects.
- Machine settings, including barrel temperature and screw speed, significantly
influence the quality of molded parts. - Continuous monitoring and process optimization can prevent and rectify silver
streaks.
