Injection Molding Defects Quiz

What defect occurs when excess material escapes the mold due to high injection pressure?

Flash is a direct result of high injection pressure causing melted plastic to escape from the mold. In contrast, silver streaks and welding marks arise from issues related to air entrapment and insufficient fusion, respectively.

What does high injection pressure do to molded products?

High injection pressure often leads to size inaccuracies, causing products to swell beyond their intended dimensions. This results in poor fit with other components and affects functionality.

What are silver streaks in molded items a result of?

Silver streaks are caused by trapped air or moisture during the injection process. High speeds can trap air, while low temperatures can lead to moisture evaporation, both resulting in visible streaks.

What happens when injection pressure is too low?

Low injection pressure leads to underfilling of molds, which results in smaller product dimensions. This can create issues in functionality and fit with other components.

What defect occurs when two molten plastic streams do not merge correctly?

Welding marks form when two streams of molten plastic meet in the mold but do not fully bond due to improper temperature or speed conditions during injection.

How can high injection speed lead to defects?

High injection speed can lead to defects like silver streaks because it traps air in the melt flow. This occurs as the plastic flows too quickly, leaving imperfections on the final product.

What impact does improper mold temperature have on product quality?

Improper mold temperature can prevent proper fusion of molten plastic streams, leading to welding marks that compromise both appearance and structural integrity of molded parts.

Why do bubbles form inside molded products?

Bubbles occur when air gets trapped within the melted plastic during injection. This can compromise product integrity and quality if not managed properly.

What is a common result of high injection pressure on molded parts?

High injection pressure can cause flash defects that necessitate additional trimming and post-processing. This increases production costs and may lead to wasted materials and time.