In order to clarify yarn motion in an interlacer, we take photographs of yarns during process by using a high-speed cine camera, input time series data of yarn positions to a microcomputer by using a digitizer and analyze them. Results obtained are as follows.
(1) The position where opening part is processed is limited to the vicinity of theair jet nozzle, and tangling parts are processed on both sides of the opening part.
(2) The yarn motion at plane of the air jet nozzle consists of ballooning and traversing the jet axis : Yarn that balloons inside the left half circle of the yarn duct in the same direction as theair flow for a certain constant time traverses the jet axis to its right half circle, and continues ballooning in the opposite direction there. The yarn again traverses the jet axis to the left half circle after the constant time. The yarn locus is a modified form of letter 8. Ballooning directions inside the left and the right half circle are opposite to each other, and are the same as the air flow direction.
(3) In the vicinity of the edge plane inside the yarn duct, the yarn motion depends upon process factors. The yarn balloons inside the left or the right half circle, or in the whole yarn duct independently of the air flow direction. Outside the yarn duct the yarn moves in a wider region when the air pressure, the yarn speed or the feed ratio increases.
(4) The yarn motion is almost symmetric in the yarn duct axial direction with respect to plane of the air jet nozzle. The yarn motion depends upon that at plane of the air jet nozzle. The degree of dependence is large when the yarn locates in the vicinity of the air jet nozzle or the feed ratio is small.
(5) Yarn ballooning period is small inside the yarn duct and takes the constant value of 0.4ms for every process factor. Outside the yarn duct it is relatively large and yarn vibrates slowly in the case of the large feed ratio.
(6) With the decrement of the air pressure or the yarn speed, the frequency of traversing the jet axis is large. In the case of the small feed ratio, the yarn locates near the yarn duct axis. With the increase of the air pressure or the feed ratio, the yarn at plane of the air jet nozzle locates in the vicinityof the jet exit for an instant and apart from it for a longer time.

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In the manufacturing process of man-made leather, the surface of man-made leather is embossed as well as natural and synthetic leather. It has been experimentally ascertained that in this process the surface is better embossed by using the heating and cooling embossing method than by the former method. To put this new method to practical use, a heating and cooling embossig machine fitted with a embossing roll (600mm in diameter) was made on an experimental basis.
The surface embossed was examined, and some problems of heat conduction were investigated. In order to heat and cool with the same roll, an induction heating apparatus was used for heating, and water vaporization for cooling inside the roll. By running this test machine, the characteristic curve of the core was obtained.
Furthermore, to investigate the cooling characteristics of the roll, a heat conduction model was constructed by solving the differential equation for heat conduction by finite element method.

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