In-Depth Analysis of Sink Mark Defects in Injection Molded Products | Causes and Complete Solutions for Indentations at Ribs, Blind Holes and Grid Areas
I. Defect Overview: During injection molding production, the outer surfaces corresponding to reinforcing ribs, blind-hole screw bosses and grid rib positions of plastic products are highly prone to local sinking. The industry collectively calls this sink marks (shrinkage indentations). Mild sink marks affect the appearance of products and fail to meet the shipping standards for appearance parts; severe sink marks are accompanied by internal vacuum bubbles, reducing product structural strength and causing batch defects, raw material loss and delivery delays, making them a high-frequency pain point in the production of automotive parts, logistics baskets, daily necessities and home appliance housings...
Technical Insights | Causes and Systematic Improvement Solutions for the Ring-Shaped Halo (Gate Smear / Haze Ring) Around the Injection Gate
During precision injection molding mass production, many appearance parts show a typical defect: a ring-shaped dull halo forms around the gate, commonly called gate smear or gate halo in the industry. This color-difference defect directly affects the appearance grade of products and, in severe cases, directly causes batch defects, raw material loss and delivery delays. It is widely seen in the production of home appliance housings, 3C accessories, daily necessities and automotive appearance plastic parts. I. Defect phenomenon: a highly recognizable ring-shaped dull halo forms around the gate opening, with dark and uneven color...
Comprehensive Analysis of the Causes of Injection Mold Sticking Faults and Targeted Solutions
Injection mold sticking (mold sticking to the mold) is a high-frequency quality defect in plastic molding production. Specifically, after the mold opens, the plastic product firmly adheres to the surface of the front mold or rear mold cavity/core and cannot be demolded and removed normally, easily causing product scratches, deformation and scrapping, while also delaying the production rhythm, reducing injection molding production efficiency, and seriously affecting mold service life and mass-production stability. Combining first-line injection molding production practical experience, this article comprehensively sorts out the core causes of mold sticking and related product shrinkage faults, analyzes the problems from multiple dimensions including injection molding process parameters, mold structure design, mold surface condition and gating system, and provides standardized, implementable rectification countermeasures, providing technical reference for injection molding manufacturers to quickly solve sticking problems and optimize molding processes.