A study of flat-bed knitting technology for three-dimensional preforms

To enable shaped preforms to be produced accurately, it is essential to have a full understanding of the geometrical properties of the structure and the effects that the various shaping techniques produce. This publication discusses the technique of three-dimensional shaping and its affects on the geometrical dimensions of a hemispherical form.

In the paper the calculation procedures employed to produce a knitted hemisphere shape are defined and relationships are established between the planar structure and the three-dimensional preform. The first part of the study demonstrates three-dimensional shaping with conventional knitting yarns. However, it was acknowledged that technical textiles employ high or low modulus yarns (performance yarns) to enable the desired properties of the structure to be achieved. Therefore, in the second part the use of technical yarns in creating three-dimensional knitted structures is reported.

The results demonstrate that an interesting phenomenon was occurring involving distortions within the knitted structure. Further research is currently being undertaken to prove the theory that the internal distortions that occur as part of the shaping process are predictable and exact shapes can be produced. This will lead to the modelling of the hypothesis for a variety of structure types.