- 1 1. Cotton Storage & Packaging System
- 2 2. Seed cotton
- 3 2.4 Effects of Improper Packing/storage
- 4 3. Cotton Ginning
- 5 4. Cotton Spinning
- 6 5. Fabric Forming
- 7 6. Garmenting
- 8 6.1 Pre-packing
- 9 7. Conclusion
Cotton storage & packaging system in textile deals about how cotton right from its picking stage till finished apparel stage is been packed and stored.
The ideas and methods vary in each stage of the process as certainly these have impact in the further stages in parameters like quality and aesthetics. A small mistake in this chain (picking-ginning-spinning-weaving -garmenting) due to improper storage or packing may not cause a serious impact over the parameters but still can lower the brand value for the specific department where the mistake has occurred.
1. Cotton Storage & Packaging System
Storage and packaging system is one of the essential part of any industry even though it appears to be lesser important. In textiles, right from fibre stage to finished product, storage and packaging plays a crucial role as it has impact beginning from quality till aesthetics.
Cotton been harvested from farm (i.e. seed cotton) has to be first initially packed and stored, then from there on it has to be taken to the ginning process where the seed particles present has to be removed. Then has to be properly packed so that it properly reaches spinning warehouse.
Then in spinning at various sub sections packaging is carried out for movement of its feed from one section to other. So, here all the packing is done continuously along with machine run instead of doing it separately.
Whereas winding is a separate part in spinning which is specifically designed only for the sake of packaging to form cone, which has to be sent as raw material to weaving section. During weaving the output obtained is in the form of roll, which can be sent to the apparel manufacturing unit in either roll form or folded form.
In garmenting unit the storage of fabrics depending on the fabric form they receive plays a main role on as far as storage utilization is concerned. After garmenting the garment has to be packed with help of some accessories to get a finished form, some pre actions such as trimming and ironing also has major influence regarding packing.
The final folded form of packing a finished cloth is the final part where aesthetic parameter dominates since it has to reach the retailer and the customer has to be attracted even the way it is packed.
2. Seed cotton
2. 1 How cotton is Harvested?
Cotton is harvested twice in a year. Cotton Picking is the first process where the cotton is taken away from the plant along with the seed. Earlier days cotton picking was done manually so that the cotton quality was dependent on the handle of the labour. Nowadays we go for machine harvesting with the help of rollers or mechanical brushes to remove the boll from the plant.
2.2 Necessity of Seed Cotton Storage
Rain damages the cotton by increasing moisture content, reducing colour grade, causing rot and heating of the fibres. Wind blows away the exposed cotton so that the salable lint decreases. These unavoidable climatic changes will decrease the profit of both cotton producers and ginners where the cost of ginning is being increased. So the storage of seed cotton is considered to be important.
2.3 Machines and Methods
In earlier days Trailers were used to move harvested cotton from the field to cotton gin. Also the trailers were limited. This led harvesters to sit idle until the cotton was ginned and made available to them, which increased the harvesting period. The need for an improved storing and transporting system led to the development of the module builder which is followed in other parts of countries like United States.
2.3.1 Conventional Module Builder
In this system cotton is dumped by the harvesters into the module builder and the cotton is compacted into trapezoidal shape. Modules are made of either wood or metal. Here hydraulic systems and expanded wire sides to allow air to escape during dumping are the methods adopted for acquiring the shape.
The dimensions may be as follows 7.5 feet wide, 32 feet base, and height of 11 feet.
2.3.2 Recent Developments in Cotton Storage
Developments produce different module shapes and sizes compared to conventional modules but the seed cotton quality in the package remains same.
22.214.171.124 Case IH Half – Length Modules
The automated cotton picker forms the half-length modules with minimal action on the operator. The operator’s manual provide by the manufacturer provides guidance on the operation of the module forming system.
The modules formed by the Case IH module Express cotton picker are 16 feet long, rectangular and trapezoidal in cross-section. Those modules are protected with a cover similar to conventional modules but shorter in length.
126.96.36.199 John Deere Round Modules
The John Deere cotton picker forms round modules that are fully enclosed on the circumference by a specially engineered polyethylene film that protects the cotton while also providing a comprehensive force to maintain the module density. The film materials are sized to lap up a couple of inches on the ends of the round module so that water flowing on the ground surface cannot enter the seed cotton. It may weigh about 6000 pounds.
2.4 Effects of Improper Packing/storage
A well-formed and covered module must resist moisture collection and prevent from moisture penetration and wind loss. The impact of the poorly protected modules can be observed in gin when modules are exposed to significant rainfall.
2.4.1 Man-made Damage
The most severe and obvious damage is often caused by workers handling during installing or removal of covers. Proper practices and awareness to the workers can avoid this damage.
2.4.2 Ultra-Violet Exposure
Prolonged exposure to UV rays cause a significant breakdown of protective coating on the module covers, sometimes these protective layers from the covers may break down and fall over the seed cotton, which forms contamination. Covers should be thrown away before a situation like this occurs.
3. Cotton Ginning
Ginning is the process of separation of fibre from cottonseed. A ginning unit performs ginning and pressing operations to convert lint cotton into a bale. In modern days cotton handled by press system gives very large forces to form a bale.
The packaging system consists of a battery condenser, lint slide, lint feeder, trampers, bale press and bale tying mechanism. This system may be supplemented with systems for bale conveying, weighing and wrapping. The bale press consists of a frame, one or more hydraulic rams and a hydraulic power system.
Hydraulic pressure locks the doors, gives positive locking. The unlocking operation opens all press door simultaneously making the entire bale accessible for tying out and handling. A Standard bale dimension is 1.4m length 0.51m wide and 0.84m thickness. It may weigh around 226.8 Kg.
After baling they are covered with a lower GSM cotton knitted or woven cotton fabric and sent to mills. Improper packaging for instance, misplacing of fibres before baling can spoil the properties of the fibres due to the pressure applied during baling.
4. Cotton Spinning
The bales which are brought from ginning industry is preliminarily tested in HVI and sorted parameter wise in warehouse so that property wise variation in the yarn can be avoided right from initial stage.
In spinning we have different sections like blow room, carding, draw frame, simplex and ring frame. At ring frame section final product yarn is obtained. The feed material and the output obtained vary for each section.
For transfer of output of one section, which is going to be the feed for the next section it has to be packed. In earlier days the output for blow room was lap, which was formed by a lap forming unit, which are now currently not much in practice as many mills have switched towards chute feed system.
4.1 Sliver Can
The output of carding, combing and draw frame is sliver. So this sliver packed from card has to be sent to draw frame and then for draw frame both the feed and output are slivers. So here, we use a sliver can in which the sliver is packed by unfaltering the properties of the sliver.
Coiling is the process by which the delivered sliver is uniformly deposited in a sliver can in an orderly manner.
4.1.1 Mechanism and Methods
The objective of the coiler mechanism here is to lay the condensed sliver delivered by the calendar rollers in a cycloid manner in cylindrical can, so that sliver from the can may be pulled out at the next process without becoming entangled or stretched.
The sliver packing apparatus for packing sliver into a sliver has apparatus consisting of turntable for rotating the sliver can, a coiler head comprising sliver condensing, sliver delivery tube, compressing plate and rotating plate portion of compressing plate.
A standard for holding coiler head and sliding means for maintaining the compression plate of the coiler head in constant which are for ensuring uniform pressure contact. For carding only certain additional parts such as coiler trumpet and coiler calendar roller are additionally present though the mechanism remains the same in both the cases.
Cycloid deposition of sliver has proved to be most advantageous method of filling a can. Here two shifting movements of the deposition point are carried out simultaneously. As the coiler plate and can are rotating, the delivered sliver continuously deposits in the can on a circle but the deposition of the circle is constantly shifting, so a helical arrangement of circle is produced within the can.
188.8.131.52 Over Centre Coiling
Over centre coiling is the coiling where the diameter of circle of the sliver i.e. the diameter of the coils is greater than the radius of the can. Over centre coiling is generally used in small to medium-sized cans up to 24” diameter.
184.108.40.206 Under Centre Coiling
Under centre coiling is coiling the can where the diameter of circle of the sliver is less than the radius of the can. Under centre coiling is used in larger diameter cans.
4.2 Trays and Trolley
Plastic trays and trolley can be used for storage and transport of products like roving bobbins and ring cops. Empty and fully wound roving bobbins both have to be stored. The wound bobbins stored is then transferred to ring frame section.
The same way empty cops and yarn cops are being stored and the ring cops stored are transferred to winding section with the help of these.
This is a major department where the ring cops are converted to cones which has to be sent as raw material for weaving. Since the warp yarns has each end of length above 1 km, a group of cops are used and winded into a cone which may weigh around 2.5-4 Kg depending on count.
So in order to make this we have to make into cone. Auto coner is a machine which winds ring cops into cone automatically.
Auto coner machine consists of bobbin holder and plate, bobbin magazine in which cops has to be preloaded (6-9), yarn tensioner in order to maintain uniform tension throughout, yarn splicer which performs knot free joining after yarn breakages, yarn clearer which removes faults in yarn and a winding arrangement at the top.
Once the cops are preloaded and machine starts running according to clearance level it automatically clears faults and packs the yarn in the form of cone.
In order to achieve high quality if highest clearance value is set, since each splice is also considered as fault this series of splices only reduce the quality of yarn rather than increasing.
5. Fabric Forming
Weaving is the section where a series of yarns are used as warp and weft yarns are interlaced between them to form a fabric. At the end of weaving process the cloth is obtained in form of roll. This roll has to be taken for inspection to find out whether any fault has occurred.
The same way in knitting a fabric is formed due to looping of hosiery yarns. Anyways after weaving/knitting the fabric has to be sent to a garmenting unit, so it can be either sent as a roll form or folded form.
5.1 Fabric Folding Machine
Fabric folding machine is a highly efficient tool for folding the fabric without altering length and width of the fabric. Basically folding machines are designed with double drive, which are synchronized with dancing roller and ensure tensionless fabric lapping/ rolling.
5.1.1 Double/Four Fold Rolling
Double/four fold rolling machines are designed for rolling the fabric with 2/4 folds on the fabric over surface winder. Here it has multi synchronization, which does not create stretch, elongation and bowing effect. With help of electronic counter meter, machine automatically stops and cuts.
5.1.2 Double Fold Plating
It is perfect tool for plating the fabric one metre fold. Fabric is single/double folded and plated at high speed. Accurate metre folds which can be adjusted from 90 cm to 120 cm.
The output of apparel industry is the finished garment. The finished garment must be packed with certain standards.
Pre-packing includes ironing, metal free inspection, folding. Good packaging of garments increases the sales at retailer’s point. Finally, the garment is packed in carton box.
Each carton box does not contain random garments instead it contains garments of specific sizes and colours of certain ratio. The garment ratio depends on customer requirement and order booking.
It is a mechanical finishing process done to remove creases and to impart flat appearance to a garment. It is done with the help of heat and pressure with or without steam. In garment industry, pressing is also called ironing.
After pressing, the garment is folded into pre-determined area. Folding of garments is also based on buyer’s requirement and meeting the standards. The folding procedure varies from style to style of the garments.
For instance, pants are half folded whereas shirts are folded in semi stand up type. The major types of folding the garments are stand- up, semi stand-up, flat, hanger and half fold. Depending upon the garment type, the folding style is chosen.
6.1.3 Metal detection
In garment industry, metal detection is an important process in production process. Buyers recommend to do metal detection so that their product is harmless and free from metal contaminants. Tunnel conveyor metal detecting is the effective way followed in garment industry.
Hand-held and static metal detectors are used to locate the metal fragments when there is knowledge of metal presence in a garment. The metal detectors can detect the metal sphere (ferrous) of 1.2mm diameter.
There are two types of detecting systems where one can detect all metals present in a cloth and another can detect only ferrous metals. Depending upon the garment manufactured and the buyer’s requirement the metal detection type is chosen.
6.2 Packing of garments
6.2.1 Packing with polybags
Normally, the garment is packed in polybags before placing them in carton box. There are two types where one is only a single garment is packed in polybag and another is blister packing which involves more than one garment are packed in polybag according to colour and size ratio.
6.2.2 Packing without polybags
There are three major packing types without using polybags. The first type is solid packing where the carton box includes garments of single colour and same size.
The second type is ratio packing where the carton box includes garments of same colour but of different sizes according to the ratio given. For example, S: M: L: XL = 5: 7: 7: 5.
The third type is mixed packing where the carton box includes garments of different colours but of same size or garments with different sizes and different colours in particular ratio form. For exports, a set of cartons like 6 or 12 or 24 is packed as one giant box which is called as cartooning.
As packaging plays an important role in garments in the view of aesthetics, if there is an improper packing it may not give good appearance which may become a reason for rejecting by customer. So the buyers will be keen about how innovatively the garment has been packed so that to impress the customers easily.
Thus the major sections where storage and packing system is involved in cotton’s journey from harvesting till garment has been discussed and its role and mechanisms has been explained.