Abstract
The forces applied on sewing needles during penetration into fabrics were measured by using a penetration behavior tester. The experiment was conducted on 24 different kinds of fabrics and measurement was done 100 times for each fabrics at low fixed crank shaft speed of 2 r.p.m. The results were shown in Histogram. Fabric factors, shown in Texture Graph, which affected penetration forces were discussed.
The results indicate that the maximum penetration forces (Wp, 2) into woven fabrics are affected by thickness t, weight w, packing factor P.F., cover factor Kc, and the initial modulus E, and that Wp, 2 increases in proportion to the increase in their factors values.
On closer examination, however, fabric factors affecting Wp, 2 were found to exhibit somewhat dissimilar characteristics where
i) Wp, 2 is affected mainly by t, P.F., and Kc.
ii) Wp, 2 is affected mainly by t, PP., Kc and E.
iii) Wp, 2 is affected mainly by E.
With the increase in Wp, 2, the range in Histogram became larger and asymetry in distribution was observed.
The value t for the knitted fabrics used in this experiment was larger, and values P.F. and E were smaller, than those for woven fabrics. The maximum penetration forces into knitted fabrics were similarly affected by fabric factors specified in ii) above. Packing factors for the knitted fabrics being small, Wp, 2 had a larger distribution range with higher penetration level, as is shown in Histogram.
