Common Defects in Injection Molded Products: A Sharing
Common defects in injection molded products, like flaws in a work of art, not only affect the product's aesthetics but can also weaken its functionality and durability. These defects vary in form and have complex causes, representing technical challenges that need to be overcome in the injection molding process.
Among them, sink marks are a common defect. Like the marks of time etched on a smooth surface, they make the surface of injection molded products uneven, losing their intended smoothness and luster. This is often due to uneven volume shrinkage of the plastic during cooling, and is closely related to process parameters such as mold temperature, injection pressure, and holding time.
Weld lines, on the other hand, are like the traces of two rivers meeting, dividing the originally complete surface into two. Their appearance means that two streams of molten plastic failed to fuse perfectly within the mold, leaving a distinct boundary. This not only affects the product's appearance but can also become a weak point of stress concentration, reducing the overall strength of the product.
Bubbles and voids are also defects in injection molded products that cannot be ignored. They are like hidden cavities underground, making the internal structure of the product loose and fragile. These defects often stem from moisture or gases in the raw materials that are not completely removed, or from excessive injection speed causing gases to be trapped within the plastic.
Even more serious defects, such as scorching, deformation, and flash, further exacerbate the quality problems of injection molded products. Scorching is the result of excessive thermal decomposition of the plastic at high temperatures, deformation stems from unreasonable mold design or uneven cooling, and flash is the product of plastic overflowing from the mold gaps under high pressure.
The common defects in injection molded products are numerous and have diverse causes. To fundamentally solve these problems, it is necessary to start from multiple aspects, including raw material selection, mold design, and process parameter adjustment.