Methods and Instruments for the Calculation of Mould Capacity

JSGT 1952 V36 T300-T326

A detailed description is given of the methods used in estimating the volumes of some simple solids which have applications in mould design. These methods include: arithmetical calculations, methods using templates and models, simplified models, Mohr's graphical method and the Gregg volumeter. The application of this last-named instrument, which is of original design, is illustrated by reference to circular, non-circular, oval and rectangular sections and combinations thereof. In brief outline the steps which are taken in the design of blow-moulds and parisons are described, indicating clearly the meanings of the terms used. Useful formulae are given, by which volume changes may be determined from changes in dimensions. The procedures are illustrated by reference to simple profiles based on different assumptions as to over-capacity and run­down allowances. A final section is devoted to some methods of estimating surface areas. The Gregg volumeter can be adapted for calculation of moments of inertia, centre of gravity, static moment, etc.

C. V. Gregg & W. R. B. Frank