SECTIONAL WARPING:-
SECTIONAL WARPING PROVESS/STRUCTURE AND WORKING PRINCIPLE OF WARPING MACHINE:-
Indirect warping or Sectional warping:-
In this method of warping , the warp ends are first wrapped on drum then transferred on the weaver's beam . This warping method is mostly used for the warping of multiple yarns, multi color warp, and continuous filaments yarn. The single ply yarn can also be used in this machine. Since the warp ends are wrapped over the drum in number of sections so that warping with less number of warp package is possible in this method. This method becomes more useful when the required warp length is very low.
Structure and working principle of indirect or sectional warping machine:-
The common parts of indirect or sectional warping machine and their working described below:-
CREEL:-
The yarn package are mounted on the creel . It is very important part of the warping machine . Creel is a frame of round or square section pipes and iron channels . The cone holders are arranged in vertical column on both sides of the creel 50 columns of cone holders on both side of the creel are there in creel of the sectional warping contains 8 rows one each side . The number of columns varies according to the requirements of creels capacity . In this creel the yarn packages are mounted on the cone holders from outside of the creel. After loading the yarn package on the creel, the stands of the are revolves at 180 degrees. A yarn guide and a tensioner are provided in the creel for each warp end. These are mounted on the iron frame which can move away by rotating hand wheel or electric motor. The yarn coming from the package, first of all passes through the ceramic yarn guide than it passes through the yarn tensioner.
The main of the tensioner is to impart a sufficient amount of tension to the yarn . Normally invented cup and dead weight washer type of tensioner is used in the warping machine. The number of washers and their weight depends upon the yarn count to be used in the warping process . As the yarn count becomes finer from coarser, the tension of all tensioner reduced its weight is also reduced if necessary. In automatic creel , the tension of all tensioner is reduced or increased by a mechanism, which is operated by an electric motor. Now warp end passes through many ceramic guide which are arranged at equal distance to each other . The distance depends upon the length of the creel. The main objective of these guide is to keep separate each end and to prevent end to end intanglement during warping. The second objective of these guide is to provide enough support to each end of the yarn sagging problem creates due to insufficient support to the yarn during warping because a long length of yarn tries to sag due to its own weight . Thus enough support needs throughout the passage of the warp ends. Now the next passage of warp end is drop wire . Its objective is to stop the machine immediately when end breakage occurs. The creel is equipped with fully automatic warp stop motion . The indication lamp on each row is provided in the creel , whenever end breakage occurs the indication lamp put on immediately and the machine is stopped. These indication lamps helps the operator to identify the correct situation broken end in the creel.
SEPARATING RODS:-
The ends coming out from the drop wires passes between the separator rod. The ends of the first top row pass under the top separator rod. End of the other rows are passed through separator rods are passed through seperator rods as per rows number respectively.
A seperator rod helps to prevent the warp ends to be entangled to each other and makes the smooth movement of ends during operation. It play a very important role in the warping of multicolor warp of single-ply yarn which necessary for sizing . The warp separation leases are inserted with the help of the separator rods.
LEASE REED:-
It is just located just after the seperator rods. Its function is to help to insert lease ( the lease contains two string) . All the odd number of ends pass over the first string , and even number ends pass under it. Now odd number ends change their position and pass under the second string. The even ends also change their position too pass over the second string.
Image of lease rod.
The reed is designed in such a way that the warp ends are divided into two layers whe it is lifted. A pneumatic cylinder is used to lift or lower it. In some machines toothed racks , gears and electric motor performs this action.
FLAT OR V REED AND ITS MOUNTING TABLE:-
The yarn now passes through the dents of flat or V-shaped reed. The main role of its is to keep the warp ends parallel to each other. It also maintains equal space among all warp ends . The number of ends per inch in the weaver's beam depends upon the reed count and denting order used.
This reed is mounted on the reed table which can move left and right direction by rotating hand wheel fitted at one side of the table . Reed can also be turns by certain angle for adjusting section width whenever flat reed is being used . When the V-shape reed is used , the adjusting table has the mechanism to reduce or increase the width of the reed .
GUIDE ROLLER:-
The warp ends are now pass between two guide rollers. These rollers are made of steel, teflon , or vacalite fiber sheet . Length wise grooves are made on these rollers which helps to spread the warp end in the section.
These rollers are not driven positively. Yarn tension helps to rotate these rollers.
WARPING DRUM:-
This is a metallic drum . Its diameter varies from 2.5 to 3 mts according to the machine. The length of the drum varies according to the maximum beam width required to be warped . The one side of the drum is designed in conical shape. The cone length varies from 1100-1200 mm.
The surface of the conical portion of the drum is made rough to prevent slippage of yarn during warping . The drum rotates by electric motor in clockwise direction during the warping process.
HYDRAULIC DISC OR DRUM BRAKE:-
The main function of the brake in the warping machine is to break the movement of the drum rotating at high speed in case of machine stoppage
Two types of brake are used in the machine. In this the drum brake system, the drum is mounted on the shaft of the warping drum . It rotates with a warping drum. A brake belt rests on the brake drum. One end of the belt is fixed and another end is connected to the hydraulically operated arm. When the machine stops immediately. This braking system also provides tension to warp during the beaming process . In the disc brake system two brake disc are mounted on the drum shaft at each side of the drum. Brake shoes also fitted on each disc. These shoes are operated hydraulically.
When the machine stops, brake shoes act immediately and grip the disc . Thus machine stops immediately. It also provide tension during beaming process.
DRUM TRAVERSING MOTION:-
The whole machine is mounted over the travese rail. Four wheels are provided in the machine which makes the machine moveable in left or right direction . A gearing system and electric motor are used to perform traverse motion to the drum .when the yarn is wound over the conical drum , the drum moves gradually to achieve the conical shape of the section. Square threaded shaft rotates through gearing and an electric motor with a drum . This shaft carries the drum in the left direction during warping . An electronic encoder is fitted at one end of the threaded shaft, which counts the ration of the shaft from the starting of the section till the completion of the section . When the section is completed the machine moved in left direction by pressing a reset push button . The machine travels the distance equal to distance travelled in the right direction equal to the section width .
WAXING DEVICE:-
It is an optional device but very useful to improve the quality of warp yarn during the process . It is located between the warping drum and the beaming system. In this device , three rollers are used. Steel tray is used to fill the chemical to be applied to the yarn . The middle roller is mounted over the tray.
Nearly half portion of the middle roller immerse in the tray. The other two rollers guide the warp yarns only. A chain sprocket is mounted at the end of middle roller which receives the rotational motion through the electric motor. The speed of the middle roller is controlled by an AC drive . When any require chemical is applied to the warp , the liquid is filled in the chemical tray. The middle roller rotating in the opposite direction of yarns touches the surface of warp. The surface of the roller lifts the liquid and applied it to the yarn surface . The amount of chemical to be applied is regulated by adjusting the speed of middle roller.
BEAMING SYSTEM:-
When the warping is completed, then it is needed to to transfer the warp on the weaver's beam. This transfer of warp from drum to weaver's beam is called beaming process. The beaming process is mainly consist of beam sliding arrangements and beam traversing arrangement and beam driving drive mechanism. The empty beam is mounted on the beaming system by means of a loading system. A iron frame on each side of the machine slide over the slide rail . These frames are moved left and right direction with the help of square threaded shaft fitted across the width of the machine. When this shaft rotates in the threaded brackets attached with the iron frame, it carries the iron frame left and right direction. The left side frame can be moved also by a hand wheel which moves on the toothed roller with the help of gear.
The adaptors mounted on each side of the beam are entered in the hollow shaft. These shaft can be lifted or lowered accordingly to required by hydraulic pressure. The hollow shaft of the left rotates freely but the right shaft has a positive drive . This shaft rotates the beam during beaming. The shaft receives the rotation and motion through an electric motor and the gear box through a universal joint which maintains the alignment automatically during lifting and lowering the beam.
FULL WARP LENGTH STOP MOTION:-
It is fully electronically controlled system. A shaft in order is mounted on the left side of the warping drum which counted the rotation of the the warping drum. A control pannel converts the rotation of drum into length in meters automatically when warp length reaches completion, the machine stops automatically before few meter warp length. Now machine comes in slow speed mode and completes the warping of the remaining warp length and becomes stationary. This system is more useful during chance of brake failure.
MULTI LEASE STOP MOTION:-
This is digitally controlled motion . This motion helps to insert more than one lease ( multi lease) in one warp beam. Suppose we have to make three small warp beam, say 600 meters , length of each beams. During warping we make a beam of 1800 meters . We insert leases at the beginning and after 600 meters of warp length . When we start the machine after insertion of the initial lease , the machine stops after 600 meters of warp. Now the second lease is inserted and the machine is started again , stops after 600 meters of warp. The operator inserts the third and final lease in the warp and starts the machine again. During beaming , the three warp beam are separated. Thus every beam has an individual lease in it and time saving occurs in the process.
HYDRAULIC PRESSURE SYSTEM:-
A hydraulic pressure device is used to generate pressure to bring up and down the beam , pressure also imparts tension to the warp during beaming. Hydraulic pressure controls the compactness of the beam . Hydraulic pressure breaks the movement of the rotating drum in case f big machine stoppage. Generally a cuboid shape oil tank is used which is located at one side of the machine 68 number hydrolic oil is filled in this tank. A geared oil pump is mounted on this oil . The oils enters the oil pump through an oil filter which does filter the oil. The pump's shaft is connected to the electric motor.
This motor rotates the oil , the outlet of the oil pump is connected to the pressure distribution arrangements . This distribution arrangements has a magnetic valve, pressure regulator and oil pipes. The magnetic valve helps to make oil supply on and off in various point according to requirements. The pressure is varied by using a regulator during beaming . A pressure motor is used to read the actual value of pressure. Push buttons are used to lift or lower the beam. This is an integrated AC inverter drive. Then drive operates three electrical motor( working motor, and machine beaming motor and machine travesing motor). The speed of warping and beaming is controlled by this drive . During the warping process the required warping speed is entered into the monitor . During the beaming process , the required speed is increased or decreased by using a pot in the machine.
SIGNAL LAMP:-
The signal lamp is located on the left side of the machine. There are three types of light used in this lamp. A green lamp means warping or beaming under process.
Red light enables that the machine to be stopped for warp breakages or mannual stop . The white lamp enables that section length has been completed.
MONITOR:-
This is located at the right of the machine. It has a display and key board . All the warp parameters machine , parameters are fed in this monitor. This sends the digital signals to the control pannel.
If any type of error occurs during operation, which appears in this display, it provides all the operational information to the operator.
PROGRAMME LOGIC CONTROL:-
It is also called the brain of the machine. It is a very important part of the machine . All the automatic functions are performed by this device . It is fully electronic device . It receives all the inputs from various electronic sensors, limit switches, shaft, encoders , inverter drives and hydraulic pressure control unit of the machine . The machine gets on and off according to command received from the PLC device.
PRECAUTION TAKEN DURING SECTIONAL WARPING:-
Following percussion must be taken during the sectional warping process;
1) The tension of each warp end should be equal and sufficient.
2) The creel should be cleaned by compressed air after every creel change.
3) The package size should be equal. The size difference in packaged creates uneven tension on the ends .
4) The distance between package and yarn guide should be proper and sufficient to prevent balloon formation during unwinding of yarn from package .
5) The effective working of electrical stop motion should always be ensured.
6) The distance between stop motion and lease rod should sufficient. If it is too low, it may cause unnecessary end breakages . If this distance is too high , it may cause excessive short end in warp end entanglement of ends which result in form of end breakages.
7) The distance between lease reed and flat reed or V-shape reed should be correct to minimise the end breakages at the reed.
8) Gear selection should be as accurate as possible. Incorrect gear selection result in the improper cone height of the warp beam thus the diameter of the beam at one side reduce or increase. This variation in diameter results in form of bowing in fabrics.
9) The warping speed should not be changed during the process , speed change during the process may change the length of section or tension of warp.
10) All the sections should have an equal number of ends if possible.
11) Section width should be set correctly . If section width is less than required, there will be gap between adjacent section and warp will become loose at these places. If it is more than required, the ends will over lapped and it will create end breakage during beaming
12) There should not go any short end in the beam during warp. Short end creates tappers and end breakage during beaming.
13) Every short end should be repaired by reversing the machine back direction.
14) Efficienct working should be ensured before operating the machine.
15) The oil level in hydraulic system is maintained properly.
16) The disc and brake shoe of the braking system should be cleaned by CTC or another solvent .
17) Wax , cold binder or anti-static oil should be used if required.
18) Beaming tension be selected properly. The beam should be neither much compact not much loose
19) Excess beaming tension may create deformation in the yarn .
20) The flange to flagged distance in beam should be set correctly.
21) The beam width should be two centimetre more than the reed space used in the loom.
22) The warp should be wound on the beam in the center of the barrel.
23) The flange should be tightened properly.
24) The lease should be inserted correct to prevent end crossing problem.
25) The number of ends per dent in the flat or V-shape reed should be as minimum as possible. The excess number of ends per dent in this reed result in the form of rolling . This rolling creates an end crossing problem during the unwinding of the warp on the loom.
26) Proper working of the machine should be ensured by the empty running of the machine.
27) The electrodes of warp stop motion should be cleaned perticularly .
28) The roughness of the surface of a cone-shaped portion of the warping drum should be maintained properly. If it becomes smooth, the silppage of section on this side may occur.
Ref:-https://textileadvisor.com
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