The preform is a piece with an special appearance similar to a test tube, transparent and with a smooth surface that is the interface product in the process of converting polyethylene terephthalate (PET) granules into bottles. Although this product has a very similar appearance to glass, but it is not as fragile as glass, and its durable walls provide a good possibility for transportation. In determining the strength of the pet bottle wall, choosing the right preform is the most effective factor. The appearance, performance and other characteristics of each bottle will be affected in some way by this choice .