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How to design PET preform mould

PET preform mould for plastics materials (PET) have been made in some manner for centuries. Some of these PET preform

moulds were fine works of art, as, for example, the moulds used by craftsmen in glass. The coming of the modern plastics

moulding materials brought about great advancement in this old art, and transformed it into a science. Mass production PET

preform moulding machinery has been developed, and new PET preform mould steels and alloys have been introduced to withstand

severe service. Accuracy is a requirement in modern manufacturing, and PET preform moulded plastics are produced by steadily

mounting standards of precision, which have necessitated new machine tool applications and methods.

A PET preform mould may be defined as a form for shaping a plastic material ”PET” into a finished product-here is PET

preform. PET preform moulds are made of plain carbon steel or of alloy steels, and are hardened to provide compressive

strength and hard surfaces to take and maintain a high polish under severe wearing conditions. PET preform moulding materials

require heat and usually pressure to achieve the plasticity necessary for them to flow into the shape of the mould cavity.

Pressure is required to force the material into the cavity and to hold it to shape until it is set, and to give the casting

or finished product the required strength. A PET preform mould must be polished to give the casting a good finish，and to

allow it to be ejected easily.

A mould for the general run of PET parts is divided into two halves which meet at the parting line. These halves are

mounted on backing plates which are drilled to allow passage of steam or cooling water, and which carry the guide pins which

aligning the halves of the PET preform mould. The mould halves and backing plates assembled constitute the PET preform mould

proper.

The fundamentals of mould design are discussed and applied to representative type PET preform moulds. The important

compression PET preform mould types are classified for study; transfer and jet moulding are described; injection PET preform

moulds are presented both as units and broken down into elements of design and construction. Methods of moulding screw

threads are discussed; methods of PET preform mould sinking and applications of mould base standards are shown. mould

building methods and equipment, moulded parts finishing, product design considerations and estimating methods are included as

background information. A summary of practical points in PET preform mould design and construction, shrinkage charts and a

nomenclature section provide a basic fund of data required by the serious learner.

Since many factors enter into the design of plastics PET preform moulds, and into the design of products to be pet bottle mould, it is well for product designers,

tool designers, and tool makers to have a common understanding of plastics PET preform moulds and PET preform moulding in

order to cooperate to the fullest extent in making possible PET preform moulded products of high standards of quality and

economy.