Developments in Injection Moulding—1

Injection moulding is the most important moulding process used by the plastics industry and some idea of its importance can be obtained by considering the following figures. The value of the UK market for plastics processing equipment was £60 million in 1977. Of this sum, £23 million was spent on injection moulding machines, that is, 40 % of all the money spent on plastics processing equipment in the UK. It has been estimated that one-third of all plastics materials are processed by injection moulding. At the present time the process is of greater importance to the thermoplastics industry but its relevance to the thermoset industry should not be ignored. Most ofthe equipment now used is based on single-screw pre-plasticising units. Once these machines had become established, in the 1960s, it was felt that the ultimate had been reached in machine design and utilisation. However, since that time, machines, processes and materials have undergone extensive development to make injection moulding safer, more reliable, easier to use and more economical to operate. The purpose ofthis book is to review some of the developments that have taken place in this very important area. These developments are described by specialists in the field, who have extensive industrial experience and whose contribution will therefore be of immediate relevance to those concerned with the usage and application of this, the most important plastics moulding process.