Monday, March 23, 2020

STRUCTURE AND WORKING PROCEDURE OF DRUM ( SURFACE) WINDING PROCESS



STRUCTURE AND WORKING PRINCIPLE OF DRUM WINDING MACHINE:

The common components and working of drum winding machine can be described in following steps:

DRIVE:

 in modern drum winding machines, two types of main drive systems are used.

In ordinary type winding machine, a main shaft across the full width of machine is used. The winding drums are mounted on this shaft. Rotational motion is given to the shaft with the help of a motor. The motion is transmitted to the shaft by using pulley and belt.

In automatic drum winding machine, every spindle gets driven through individual motor. The winding drum gets mounted on the shaft of motor. The machine is equipped with inverter drive. It controls the speed of motor. The speed of machine gets changed by selecting speed range in the inverter drive. A group of spindles (8 – 16) are controlled by one inverter drive.

TRAVERSE DRUM OR WINDING DRUM:

The traverse drum is mounted on the main shaft (in ordinary winding machine) or motor shaft (in automatic drum winding machine). Traverse drum has helical grooves on its surface. The traverse drum provides constant traverse speed of yarn during process. . A continuous helical groove (interconnected clockwise and counter clockwise helical grooves) around the drum circumference guides the yarn along the traverse length as the yarn gets wound onto the yarn package. A continuous helix has points of crossover of the clockwise and counter clockwise helices. To retain the yarn in the correct groove during its traverse, particularly at the intersections, one groove is made deeper than the other, and the shallower groove is slightly angled.

The traverse drum also helps to revolve the package. During operation, the package rests on the surface of the traverse drum. When the drum rotates, it also revolves the package due to frictional force acting between surface of drum and package. It revolves the package at constant speed. Gradually increasing package size during winding process does not affect the winding speed of yarn.

CRADLE:

The cradle is an arm mounted on the shaft fitted across the full width of the machine. Its function is to provide setting to package having package holders, it lies on upper part of machine on traverse drum. The package holder is mounted on the cradle. The package holder rotates on the bearings. The rubber rings mounted on the package holder grip the package and prevent to come out from package holder. A spring provides pressure to the cradle which prevent slippage between package and traverse drum during winding process.

CREEL:

It is mounted in the lower part of machine. The function of a creel is to hold the ring bobbing or the package to be wound. The ring bobbin is mounted on the creel. In the ordinary type of winding machine, a simple rod of iron is used. In the automatic winding machine, a magazine creel is used, it has the 8 – 16 bobbins loading capacity at a time. When one bobbin exhausts, it revolves automatically and fresh bobbin takes the place of exhausted bobbin.

SLUB CATCHER:

The main role of a slub catcher in the winding machine is to eliminate objectionable yarn faults during the process. It helps to remove thick  places, big knots, neps, dirt and dust from the yarn. It also reduces hairiness of the yarn. Mainly following types of slub catchers are used in different types of winding machines:

Fixed blade type slub catcher:

It consists a metal slit. Opening of metal slit is fixed. When yarn count is changed, the slub catcher is also needed to change as per count.

Adjustable blade type slub catcher:

In this type of slub catcher, two metallic blades are used. The bottom blade is fixed. Upper blade is adjustable. The clearance between both blades are adjusted when the yarn count is changed.

Electronic slub catcher:

This slub catcher gives accurate opening between the blades as per size of yarn irregularities. An electronic sensor feels the size of knot and thick place etc. and sends a command to the control unit. The control unit sends a signal immediately to the blade opening mechanism to adjust clearance between the blades. It provide accurate working and clean the yarn efficiently.

TENSIONER:

The main function of a tensioner is to regulate the yarn tension during winding process. Tension is a very important factor in winding. It plays very important role in package winding density. It also removes thin places from the yarn. The uniform tension throughout the process results in the form of good winding quality. Uneven tension during winding causes deformation in the shape of the package. Mainly following types of tensioners are used in various make of winding machines:

Conventional tensioners:

These type of tensioner has mechanical arrangement. Normally two inverted cups having hole in the centre are used. A pin is inserted through the hole of inverted cups. The dead weight washers or spring are used to impart pressure between both the cups. The yarn passes between these cups. The spring pressure or weight of washers are adjusted according to yarn count to be wound in the winding process.
.
 Automatic tensioner: 

This  is an electronically controlled yarn tensioner. It regulates the tension according to yarn count throughout the process. An uiform yarn tension results in this type of tensioner. The different types of automatic tensioners are used in various make of winding machines.

YARN BREAK STOP MOTION:

The main function of yarn break stop motion is to lift-up the package when yarn breakage or bobbin exhaustion take place in conventional type of winding machine. In automatic winding machine, this stop motion stops the working of individual package by switching-off the motor of that spindle when yarn break or bobbin exhaustion take place. This motion prevents to damage the yarn to be wound. There are two type of yarn break stop motions used in the winding machine.

Drop wire of yarn break feeler:

Drop wire stop motion is used in the conventional winding machines. A light weight feeler or drop wire is used in this mechanism. The yarn passes under the drop wire and keeps it in upward position due to yarn tension. In case of yarn break or ring bobbin exhaustion, the yarn tension releases from the drop wire. The drop wire falls in downward direction and contacts a notch or cam on a rocking shaft from which necessary force is obtained to lift the package from the traverse drum. This force lift the cradle, thus package also lifts-up and winding of such spindle is stopped.

A rod, which is free to rotate in clockwise direction due to action of the spring has its bottom, feeler wires and at a top a support plate. The feeler wires rest over the running Yarn, which is held in position by grid bars. When the yarn breaks, the feeler wires become free to turn forward & thus the rod along with the plate rotate in clockwise direction. A long U-shaped wire which is suspended to the outer side of the cheese holder-arm fulcrum and rests normally on a projection of plate is titled backward by another projection on the plate on its (plats’) rotation. On tilting, the wire comes in the way of permanently rotating cam on the rocking shaft and is thus pulled downward. This causes the package to lift from the drum and fall on the forward side which the rod is pulled to the bottom most position of the cam movement. The wire again goes out of the way of cam when the package has been lifted from the drum.

Electronic yarn break stop motion:

In this type of stop motion, electronic sensor is used to feel the movement of yarn. When the yarn winding process is in progress, the sensor feels the movement of yarn continuously. When a yarn break or supply bobbin exhaustion takes place, it sends a signal to the control unit. Now control unit releases command to the power supply unit of machine, which switches-off the power supply of particular spindle. Thus the working of that spindle stops immediately. This stop motion is much efficient, works without failure and gives better quality of winding. There is no mechanical maintenance in this type of stop motion.

YARN GUIDE:

The main function of a yarn guide is to impart controlled guidance to them yarn. The yarn guide reduces yarn vibration and minimise it. It also helps to prevent ballooning of yarn during winding of yarn. Guides are normally made of hard smooth steel or ceramics. Selection of guide shape may be depended on the yarn motion to be controlled. There are two types of yarn guides used in winding machine. In one type of yarn guide a yarn end is required for threading and in another type of yarn guide a yarn end is not required for thread. In winding & unwinding, it is necessary to control the yarn path. For side with drawl, it is possible for the yarn to pass along a smooth unvarying yarn path. But for over end with drawl the yarn does not move along fixed path because rotary motion is imparted the yarn winding. For a give yarn speed & package size, the position of yarn Guide will determine the balloon shape & the yarn tension.

WAXING DEVICE:

The main function of a waxing device is to apply a thin film of wax to the yarn surface. The film of wax reduces the level of hairiness of yarn, makes the yarn surface smooth. It also improves the strength of yarn. In this device wax brush rotates continuously and applies the wax to the yarn surface.

CONVEYER BELT:

The role of the conveyer belt is to carry the winding packages in the container which is kept in one side of the machine. This conveyer belt moves continuously toward the collection container. When the yarn length on the package reaches to pre-decided value, the operator takes the package out of spindle and puts it onto the moving belt. The package drops into the container automatically.

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