In the part 1 of the series of this study, in order to clarify the opening mechanism, macro-scopic mass balance analyses on production process, theoretical analysis on the motion curve of opener's spike tip and observations on fiber behaviors of model bales by model plucking were conducted. In the part 2, experiments of model plucking using practical spikes and practical model bales were carried out. The dependencies of Wp and Rp on bale feeding speed, compression force of opener's bars on the bale, and on the fiber length andfiber orientation of the bale were obtained by these experiments.
In this report, a theoretical model for microscopic mass balance is presented. Simulation on the changes of Wp and Rp by time are numerically calculated by using this theoretical model by using the data obtained from the above experiments results. The effectiveness of the calculation is also discussed in comparison to practical

View full abstract

In the previous paper, a new pneumatic method for spreading carbon tow was presented. In this paper, roll spreading method is investigated as the preliminary process of the pneumatic process.
the results are as follows :
(1) Tow is spreaded easily for smaller friction coefficient between roll and tow. Therefore tow can be more widely spreaded by fixed rolls than free rolls, because the static friction force acts on the fiver for a free roll and the kinetic friction force acts on the fivber for a fixed roll.
(2) With an increase in tow tension, the spreaded tow width increases for a roll method, however, it is limited, because fiber breakage begins to occur at a higher tow tension.
(3) When the number of fiber layers in the tow thickness direction decreases, the pressing force exerted on the fiber by the upper fibers reduces, then the rate of increase in spreaded tow width decreases. Therefore the spreading rate by a back roll becomes lower than by a front roll for the spreading process using the plural rolls.
(4) Under the fixed total tow tension, the tension on the fibers located at the outer sides increases, while the tension on the fibers located at the center decreases with an increase in tow width. So the upper limit of tow width is determined by the condition that the tension on the fibers located at the center becomes zero.
(5) Each fiber is removed from adhesion state of sizing by the roll method and the tow can be opened to some extent. So the roll method is effective as the preliminary process of the pneumatic method.

View full abstract

Drawing-in process into hollow spindles on covering machines is so difficult and inefficient that its automation is especially hoped. The automatic drawing-in system, installed onto the vehicle individually driven wheels that runs around the factory floor, is developed in order to improve drawing-in operation. Results obtained are as follows :
(1) The auto-doffing system is composed of the automatic yarn draw-in apparatus, which can draw Spandex in both upper and lower hollow spindles simultaneously by air flow, and a vehicle which runs in contact with the covering machine.
(2) The developed device can draw-in 30D, 70D, 140D Spandex that are widely used and too fine to be easily drawn-in even by manual operation. Success rate more than 90% of Spandex drawing-in can be obtained by supplying the air pressure for the ejector at 0.5 MPa and for the injector at 0.4 MPa. It confirms that the developed device has practical utility.

View full abstract