Chapter 5-Compression Moulding Flashcards
What is compression molding?
Compression molding is a process in which plastic material is placed into a heated metal mold and is softened by the heat and made into the shape of the mold as the mold closes.
What is compression mo,ding used for?
It is commonly used in manufacturing thermoset plastic parts. The raw materials usually come in the form of granules and are placed in an open heated mold cavity.
What is compression moulding suitable for?
It is a high volume method suitable for molding hugh strength fibreglass reinforcements. It has the ability to mold large difficult parts. It is cheaper than other methods like transfer molding or injection moulding.
What are the disadvantages?
It often provides poor consistency and difficulty in controlling flashing and is not suitable for some types of parts. It is better suited to ultra large basic shape production.
What materials are manufactured through compression?
Polyester fibreglass resin systems, Toronto, Vespel, Poly and many grades of PEEK.
What are the six considerations to bear in mind when using compression molding?
Determining the proper amount of material.
Determining the minimum amount of energy required to heat the material.
Determining the minimum time required to heat the material.
Determining the appropriate heating technique.
Predicting the required force to ensure the proper shape is achieved.
Designing the mold for rapid cooling after it has been made into the mold.
What are the advantages of compression moulding?
There is lower cost tooling because the process does not involve a n injection or transfer cycle. Tools can be made of aluminium or lower cost grades of steel which can save money. It is good for small production runs.
