Discoloration, or ‘colour streaking’, occurs when a moulded part is a different colour than intended. Often the discoloration is limited to a localised area or a few streaks of abnormal colour on a moulded part. This defect typically affects the appearance of the part without reducing its strength. Continue reading
Jetting refers to a kind of deformation in a moulded component that can occur when there’s an initial ‘jet’ of molten material injected into the mould cavity that starts to solidify before the cavity is filled. Jetting often appears as a squiggly line in the surface of the finished component, typically leading from the initial gate of injection. This visible flow pattern can result in part weakness. Continue reading
Weld lines can appear on the surface of a moulded part where the molten material has converged after splitting off into two or more directions in a mould. The hair-like weld line is the result of weak material bonding, which lowers the strength of the part. Continue reading
Sink marks are small recesses or depressions in an otherwise flat and consistent surface of a moulded part. These can occur when the inner part of a moulded component shrinks, pulling material from the outside inward. Continue reading
It is very easy to make expensive errors when it comes to injection moulding. Quality issues in injection-moulded products can range from minor surface defects to more serious problems that can affect the safety, performance and function of the product. They can be caused by problems related to the moulding process, material use, tooling design or a combination of all three.
This is the fourth on our series of posts where we look at a number of issues that can affect the quality of the end product and some of the common remedies. This post is about vacuum voids. Continue reading