Thermoset plastics compression moulding

ISO 295. Plastics—Compression moulding of test specimens for thermosetting materials. International Organization for Standardization, 1991. 

BS2782. Part 9, Method 902A, Methods of testing plastics Compression moulding test specimens of thermosetting materials. British Standards Institute Publication. 1992. 

Figure 8.12. Typical process for the compression moulding of thermosetting plastics, (a) Load, (b) Mould, (c) Eject, stripper in. (d) (After Groves )...

Compression moulding is one of the most common methods used to produce articles from thermosetting plastics. The process can also be used for thermoplastics but this is less conunon - the most familiar example is the production of LP records. The moulding operation as used for thermosets is illustrated in Fig. 4.62. A pre-weighed charge of partially polymerised thermoset is placed in the lower half of a heated mould and the upper half is then forced down. This causes the material to be squeezed out to take the shape of the mould. The application of the heat and pressure accelerates the polymerisation of the... 

Thermoplastics are easily moulded or formed into useful articles. Once they are molten they can be injected or blown into moulds, and a variety of different-shaped items can be produced (Figure 14.19). Thermosetting plastics can be heated and moulded only once, usually by compression moulding (Figure 14.20). 

Figure 14.20 These objects are made from compression-moulded thermosetting plastics.

Compression moulding The disk is moulded directly onto the machined recess on the cathode sheet using a thermosetting plastic with silica fiber fillers. 

Compression moulding is used chiefly with thermosetting plastics such as urea and melamine formaldehyde, epoxies and phenolics. 

Transfer moulding is used for thermosetting plastics. This process is similar to compression... 

The progress of plastics utilisation is well illustrated by exchange equipment where the early Strowger equipment incorporated insulating components fabricated from ebonite and wood- and resin-impregnated paper and textiles. Later developments introduced compression moulded items in thermosetting phenolics and alkyds and the later step-by-step equipment contained up to 20% of injection and compression moulded items. 

Casein plastics tough non-flammable thermoplastics or thermosets produced from rennet casein, extruded to form rod or tube or extruded and compression moulded to form sheet. Used tor products such as buttons in which dimensional stability is not important. 

Compression moulding process mainly used to manufacture thermosetting plastics products. It employs a split mould which is heated, opened to receive the moulding material and then closed under pressure. 

Polyester resins thermosetting plastics used for laminating, encapsulation and casting, and as dough moulding compounds (qv) for compression moulding. Mainly used as liquid binders for glass fibre (and other fibre) reinforced plastics. 

Transfer moulding technique for moulding thermosetting plastics used to overcome problems inherent in the compression moulding process, such as the need for delicate inserts. 

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