108—WOOL FABRICS AS GARMENT CONSTRUCTION MATERIALS

The basic requirements of a garment in use and basic techniques in garment manufacture are briefly discussed. The relevant mechanical properties, of buckling, compression in the plane of the fabric and shearing are described and methods of measurement are indicated. It is argued that there are upper and lower limits to some of these properties in order to obtain fabrics with optimum performance. A few cases of forming a flat fabric into a threedimensional shell are discussed and their relationship to mechanical properties is indicated. A property termed “formability” of a fabric is defined. To retain a given form the fabric must be set. and it is shown that, for stitching with overfeed, there is a definite relationship between settability, formability and the degree of overfeed. Dimensional stability is discussed and measured with relation to steaming, wetting and steam pressing. It is shown how dimensional changes will influence two different layers of fabric stitched together, and how this depends on formability; also that steaming will produce a good dimensional equilibrium in a fabric regardless of other treatments such as wetting and pressing. Storing changes the dimensions towards those of the steamed fabric. A method which can be used in practice is suggested for measuring dimensional changes.