AUTOMATIC LEVEL CONTROL OF THE THICKNESS OF PRODUCT SLIVER

Abstract

The application of our automatic draft control system by Ever Even which has the decided neutral zone in controller was performed for our cotton spinning process. This application is classified into two types, one is for double and more deliveries, and the other for single delivery.*One kind of the former type is the application for automatic draft control of the variation of average sliver thickness produced from drawing frame. This automatic control means the control of long term variation of average sliver thickness produced control means the control of long term variation of average sliver thickness produced and our conventional control method is performed by so-called X-R control chart system.Form the test by Ever Even, the following are observed:(1) The variation of average sliver thickness produced from drawing frame #2 is controlled in the range ±0.5% for standard value.(2) Average counts of yarn is controlled in the same range of drawing sliver the coefficient of variation of yarn counts is about 1.2_??_1.4%. The variation of lea strength for 40S is also decreased and the percentage of lea strength under 50 lbs in controlled lot is about 9% and that of conventional lot is 19%.(3) The variation of cake weight of control lot is about 1/2 of that of conventional lot.(4) It is proved by Nyquist criterion that the stability of this control system is maintained.The short cut of the spinning process by the automatic draft control system for single delivery is proven beneficial by our mill test.It may be expected that if the draft control system is applied for draft element with single delivery to which some card slivers are fed as the same feed method of comber draw-box. excellent uniform sliver may be produced.*Draw-box with Ever Even for some sets of card (i.e., 6 sets)…Drawing frame super high draft spinning frame.*Draw-box with Ever Even for some sets of card (i.e., 6 sets)…Drawing frame…Roving frame high draft spinning frame.