Flow lines appear as a wavy pattern often of a slightly different color than the surrounding area and generally on narrower sections of the molded component. They may also appear as ring-shaped bands on a product’s surface near the entry points of the... moreFlow lines appear as a wavy pattern often of a slightly different color than the surrounding area and generally on narrower sections of the molded component. They may also appear as ring-shaped bands on a product’s surface near the entry points of the Mold parts, or “gates”, which the molten material flows through. Flow marks won’t typically impact the integrity of the component. But they can be unsightly and may be unacceptable if found in certain consumer products, such as high-end sunglasses.
Causes and remedies for flow lines
Flow lines are most often the result of variations in the cooling speed of the material as it flows in different directions throughout the mold. Differences in wall thickness can also cause the material to cool at different rates, leaving behind flow lines.injection molding defects For example, molten plastic, cools very quickly during the injection process and flow marks are evident when the injection speed is too slow. The plastic becomes partially solid and gummy... less
