Tuesday, January 13, 2015
The sectional warping machine is used for preparation of multicolored warps to be woven as striped of checked design fabrics. It is also used for doubled grey or mono-colored warps that do not require sizing. Unlike the beam or direct warping where a warper’s beam is produced that is sent to the subsequent sizing processes, in the case of sectional warping, the weaver’s beam is produced and hence does not require sizing. In the case of single yarns that are multicolored, the yarns are sized and then wound on the sectional warp beam. The yarn is wound in sections, each section having a particular width. Thus the total number of warp ends for the weaver’s beam is divided into suitable number of sections on a warping drum. The sections are then combined to form the weavers beam. Therefore, there are two distinct operations involved, namely, warping and beaming.
Passage of yarn through the machine
The passage of material through the sectional warping machine is shown in the following figure –
The supply packages are in the form of cones or cheeses. They are placed on a V-shaped creel or a semi circular creel depending upon whether stop motion is used or not.
The yarn from the creel passes through the back reed. The reed maintains uniform spacing of the yarn throughout the width of the warp.
Then the yarn passes over and under guide and drop rollers. The drop rollers impart tension to the yarn passing under them and hold the yarn tight when the machine is stopped.
From there the yarn goes through a stop motion device which stops the machine in the event of an end breakage in supply package, getting exhausted.
From the stop motion device the yarn passes through a leasing reed. The use of the reed is to form an end and end lease at the start and completion of each section. The depth of the reed is comparatively much more than that of the ordinary reed. Each end of the warp passes separately inserted in the warp at the completion of one section of warp and the reed is lowered.
This will bring all the alternate ends passing through the soldered dents, i.e. alternate ends passing through the soldered dents down, i.e. alternate ends will from the bottom line and another set will form a top line. The division of warp threads is called shed. Now a lease band is inserted. As soon as it is done, the reed is lifted. This will cause alternate set of warps, which were down in the previous operation to be lifted up and those which were on the top to be lowered. Now another lease band is inserted and the reed is brought back to its normal position, i.e. middle position.
The purpose of this leasing is to wind as well as to unwind the warp without any entanglement between threads to distribute evenly. Also it helps the yarn to maintain in position and helps to detect the broken end and mend it properly.
The yarn next passes through a V-reed which enables the width of the warp through it to be adjusted according to the width of the sections to be made.
Then the yarn passes over a measuring roller and is wound on a wooden block called swift. After winding the predetermined length of warp, leasing is carried out. The sections of threads are continued to the swift in a bunch form. Next, section is wound in the side of the previous one. The same process is continued until required numbers of sections are made on the wooden swift. Then all the sections are taken and transferred to a beam by means of running-off machine. The beam is driven by a motor or manually. The section width may vary from 10 cm to 20 cm.
Merits and demerits
The sectional warping machine has the following advantages –
- It is suitable for striped warp.
- The labor charges are also less.
- Power requirement to drive the machine is low.
- Sizing process is eliminated.
The demerits are –
- There are two stages, namely, warping and beaming.
- Warp will have to be dyed, sized and dried separately by slow and expensive processes before warping.
- Some amount of size will be removed from the warp during the process of sectional warping.
Wednesday, February 5, 2014
Beam Warping | Creels | Types of Creel
Beam warping: The warping process is intermediate between the winding and sizing processes. It produces the warper beams that are combined together as a single weavers beam in the next process of sizing. A warper beam may contain about 500-1000 warp ends. The direct or beam warping is suitable only for grey or monocoloured warps that require sizing. It involves only one operation namely warping and hence the speed and production are considerably higher than the sectional. The machine consists of a creel, a headstock, and control devices.
Creels: The creel is a stand for holding the supply packages in the form of wound packages. It enables to hold the supply packages in proper position for warping and constitutes an important component of the warping machine. No individual type of creel can be suitable for all types of yarn, counts, set lengths and different applications. In other words no single type of creel can give the same beaming efficiency for different types of yarns or applications. Hence different types of creels are to be used for different purposes. The creels used in warping are of the following types:
· Continuous chain
· Automatic and
· Special creels
As the name implies, the type of creel is V-shaped. It consists of wooden pegs horizontally to hold the supply packages. This is arranged so that the apex is in line with the centre of the machine. The arm of this V-shaped wooden frame diverges on both sides from its apex.
This arrangement enables the ends to be withdrawn easily from the supply package without touching or getting entangled with one another during passing to the back reed of the head stock of the machine.
This is rectangular in shape and hence its name. The frames are provided with pegs to hold supply packages horizontally. The frames can be increased to accommodate more number of supply packages vice versa. Each frame consists of thread guides, indicator lamps etc. It is mostly used in the slow speed warping machine.
This provides with arrangements to hold reserve package. The tail end of the running package is knotted with the starting end of the reserve package. This enables the continuous working of machine without stoppage for replacing the exhausted package with a new one. The dimension of the creel and floor space required is comparatively more than other types of creel. The creel is usually V shaped.