The heat-stretching process of acrylic fiber on Turbo Stapler has been analyzed by investigating the temperature dependence of the load-elongation properties of that fiber and by building a modelesque theory of heat-transmission process in the heat-stretching zone of Turbo Stapler-with the following results:
(1) The temperature dependence of the load-elongation properties of acrylic fiber is expressible thus: -log_e; ε=6.00-0.509w-0.0334θ ……(1) where ε=elongation w=load (g) θ=temperature (°C)
(2) The temperature of tow in any position in the heat-stretching zone is expressible thus: (a) heat exchanger model θ_x; =Θ-(Θ-θ_o; )exp(-2.68x) ……(2) where θ_x; =temperature of tow at position x (°C) Θ=temperature of heating plate (°C) θ_o; =initial temperature of tow (°C) x=distance from entrance to heating plate (m) (b) radiation model 100⁴/2T_p; ³={(tan^-1φ_x; -tan^-1φ₀; )+(tan^-1φ_x; -tanh^-φ₀; )}=0.5384x ……(3) where T_p; =temperature of heating plate (°k) T_o; =initial temperature of tow (°k) T_x; =temperature of tow at position x (°k) φ_x; =T_x; /T_p; φ_o; =T_o; /T_p; x=distance from entrance to heating plate (m)
(3) The load needed to stretch tow is obtainable as follows: w=6.00+log_e; ε-0.0334θ_l; /0.509 where w=load needed to stretch 3d single fiber (g) ε=stretching ratio (fixed according to gearing) θ_l; =temperature of tow at the exit of heating plate (°C) (obtainable from formula (2) or (3)) The relation between the temperature of heating plates and the load needed to stretch tow is a straight line within the condition of practical use.
(4) The elongation of tow at any position in the heat-stretching zone, with Turbo Stapler under any condition, is obtainable by connecting the results of formulas (1), (2) and (3).

View full abstract

It is assumed that a set of state variable is able to express the state of loom and, after one weaving cycle, the state of loom is determined only by the present state. Then, using the linearizing approximation, we have derived basic equations to express the dynamic property of the weaving process. Experimental results show the basic equations may be useful to discuss the dynamics of the weaving process and the design of loom.

View full abstract

A previous article has shown that rapid rotations of a braiding machine increases the number of its revolutions, produce variations in yarn tension during braiding, reduce the tensile strength of braids and make uneven stitches.
Measuring yarn tension with a strainmeter and an electro magnetic oscillograph has shown that yarn tension increases as the number of revolutions increases. The maximum yarn tension during braiding is unexpectedly large. Yarn tension is large when the tension weight goes up, and is small when it goes down.
A method to reduce yarn tension without reducing the strength of braids, even if the number of revolutions is increased, is studied here.

View full abstract

The horizontal air-flow method in which fibers fall freely in a horizontal air-flow is studied and their horizontal displacement is used to obtain the fineness distribution. This article describes a preliminary experiment and the theory of the descent of fibers.
The preliminary experiment in which fibers were let to fall in still air shows that the higher the fineness, the higher the velocity of falling. The experiment shows also that fibers of the same fineness vary only slightly in the velocity of their falling even if they differ in fiber length.
A theoretical treatment of fibers falling in a horizontal air-flow has shown clearly that the fibers initially fall with a terminal velocity, its horizontal displacement being proportional to (n-1)/4 power of fiber fineness, where n is a constant depending upon the posture of the fiber falling n is equal to -1.840 if fibers fall with their axes perfectly horizontal ; equal to -1.625 in case of a partially horizontal descent. These results show that it is possible to measure the fiber fineness distribution by the horizontal air-flow method.

View full abstract

This article shows how to calculate the yields of products which are classified by rewinding quantity into grades A, B and C and how to increase the yield of grade A. Used as the basis of calculation is the relation between (1) the statistical mean values and the standard deviation of a group of inputs during winding and (2) statistical mean values and standard deviations of final products.
It is difficult to lessen the standard deviation of the winding quantity of a group of inputs or Grade A in a group of outputs, but it is easy to change the mean winding quantity of a group of inputs. Therefore, by fixing the standard deviations we can formulate the relation between the yield of each grade and the winding quantity of a group of inputs and decide the most economical conditions for the rewinding process.

View full abstract