The separation of sliver delivered from a pair of drafting rollers due to air flow was evaluated experimentally by the following parameters :
(1) Size of separated fiber groups.
(2) Scatter of time interval of separated fiber groups.
(3) Time variation of separated fiber group size.
The results are as follows.
(1) The manner of sliver separation is considerably affected by the air-speeds up to 30 m/s.
Larger group separation occurs perriodically in a low air speed range.
(2) The number of revolutions of front roller n is closely related to the separation of sliver.The effect of n on separation of sliver decreases with increasing air speed, and clear correlationis observed between n and maximum time interval of separated fiber groups.
(3) Draft ratio of the drafting rollers D, affects the separation of sliver when air-speed or n islow.
(4) The ratio of periodical group separation quantity to total separation quantity is very effective to evaluate the separation.
(5) The investigation of the periodicity of separation time into fiber groups verifies that sliver is separated randonly.

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A study was carried out on a method of measurement of frictional force of moving meedles on the cylinder wall and the cam surface of a circular machine in its operation.
The horizontal (tangential to the circumferenece of the cylinder) and the vertical to the vertical (parallel to the needle track) components of the force acting on a stitch cam were measured by a strain gauge bondend on a cantilever at the end of which the cam is supported.
Comparison of the direction of the force acting on the cam with the cam angle gives the frictional coefficient between the needle and the cam, and the change of the coefficient.
The general change of the magnitude and the direction of the force acting on the cam gives frictional coefficient between the needle and the cylinder wall.

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