Fabric Sewing Part 3 : Relation between Penetration Energy and Maximum Penetration Force of Sewing Machine Needle into Fabric.

Abstract

  Generally, the maximum penetration force and the penetration energy have been respectively used by each investigator ^{2)- 7)} as the typical values in the diagram of the penetration force of the needle produced during needle penetration experiment. Upon this, it seems to be needed to clarify the relations between these two values in order to cultivate a better understanding on the problems of the penetration of the needle into fabric. In this paper, under the distributional observation of the penetration energy along the length of the needle, the distribution of the penetration energy which relates to the maximum penetration force of the needle is discussed.

  The results obtained are as follows :

(1) Relation between the penetration energy E_p (b) which is given to the needle from ℓ＝0 to ℓ＝b (at this point, the penetration force takes maximum value) and the maximum penetration force P_m is shown by the following equation, where ℓ is the interpenetrated length of the needle from the surface of the fabric, b is the height of the circulare cone on the pointed head of the needle, and a is the thickness of fabric.

    E_p(b)＝b/3・1－3/2(a/b)＋(a/b)²－1/4(a/b)³/1－(a/b)＋1/3(a/b)²・P_m

(2) Similarly, on the penetration energy E_p (a＋b) which is given to the circular cone on the pointed head of the needle from ℓ＝0 to ℓ＝a＋b (at this point, the circular cone on the pointed head of the needle has just passed through the reverse side of the fabric entirely),

    E_p(a＋b)＝b/3・1/1－(a/b)＋1/3(a/b)²・P_m

(3) The results calculated from these equations agreed well with experimental values, in both the model needle having the circular cone on the pointed head of a cylinder and the standardized needle (JIS, DB×1).