Some molded parts are not partially broken, but only have fine cracks on the surface. According to difference in their degree and appearance, more serious ones are called cracks, and lighter ones are called microcracks. Cracks are same as microcracks. It looks very similar, but in essence it has two meanings of difference, that is, cracks are not defects like voids, because added stress is arranged in polymer itself in a parallel direction, so if it is heated, it can return without cracks. In this way, cracks and microcracks can be distinguished. Among them, micro-cracks are not only generated after molding; they also occur after being placed or in contact with solvent vapors.
Gud Mould 