Can anyone tell me the process by which PET or Polyethylene terephthalate plastic is produced?
There are two basic moulding methods for PET bottles, one-step and two-step. In two-step moulding, two separate machines are used. The first machine injection moulds the preform. The preform looks like a test tube. The bottle-cap threads are already moulded into place, and the body of the tube is significantly thicker, as it will be inflated into its final shape in the second step using stretch blow molding. In the second process, the preforms are heated rapidly and then inflated against a two-part mould to form them into the final shape of the bottle. Preforms (uninflated bottles) are now also used as containers for candy. In one-step machines, the entire process from raw material to finished container is conducted within one machine, making it especially suitable for moulding non-standard shapes (custom molding), including jars, flat oval, flask shapes etc. Its greatest merit is the reduction in space, product handling and energy, and far higher visual quality than can be achieved by
