What happens if molded parts are compressed unevenly?

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Uneven shrinkage is called warpage. When areas of a part shrink unevenly, they create stresses within the part. These stresses depend on the rigidity of the part, which can cause the part to warp or change shape. This causes cracks in the parts over time.

Shrinkage of molded plastic parts can be as much as 20% by volume when measured at process and room temperature. This volumetric contraction of polymers often results in warping of parts and dimensional differences. These changes occur between the manufactured parts and the mold. In the extrusion technique, a matrix is ​​used instead of a mold.

5.What are the causes of shrinkage in plastic injection molding?
Variations in shrinkage are the primary cause of warpage, which may sound complicated but is actually quite simple. In other words, when a component is compressed uniformly in all iran number data directions, it not only gets smaller, but also maintains its original shape. On the other hand, if one part is compressed at a different rate than the others, the difference will cause stresses within the part. When a part is removed from the mold, it will warp if the forces acting on it exceed its ability to maintain structural integrity.

There are four main types of shrinkage, which are:

· Regional
This occurs when the shrinkage rate of each part differs between the areas that are closer to the gate and the areas that are closer to the end of fill (EOF); ​​typically this difference occurs between areas of the part that are thicker (the gate area) and areas that are thinner (the EOF area). One area shrinks faster than the other.