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Spinning & Weaving
  A study on materials handling in spinning mills

Materials handling covers movement and storage of everything in and around an establishment. The ideal factory would have an absolute minimum of materials handling and hence more use of mechanical appliances. The shortage of labour and increasing wages cost demand the most efficient use of labour. Proper materials handling offers opportunity for improving productivity, reducing materials wastage, minimising industrial accidents, reducing man-power, etc.

While determining the choice of equipment, the following factors should be taken into account:

-- Mode of arrival and dispatch of materials.
-- Type/shape of materials to be transported.
-- Amount of materials to be handled in unit time.
-- Storage operations and the time materials remain in storage.
-- Details of the buildings and routes.

The materials handling systems followed by the spinning mills differ widely. Some of the mills, particularly modern mills, have been using appropriate materials handling equipment. At the same time, there are mills using outdated or more laborious systems.

In this article, based on the information collected from the spinning mills during regular consultancy assignments as well as from other sources (1,2), the materials handling systems being followed by the mills have been analysed and suggestions are offered for better handling. Photographs/sketches of some trucks, which are suitable for the spinning mills, are shown in this article just to indicate the type of equipment available.

Industrial trucks

Industrial trucks are the major category of equipment used for materials transportation. For safety and bulk movement of materials, industrial trucks play a vital role. They are used to move materials over variable paths, with no restrictions on the area covered by the movement.
The major types of industrial trucks are:

1. Hand truck
a)Two wheeled hand truck
b)Dolly 
c)Floor hand truck

2. Pallet jack
a)Manual pallet jack
b)Powered pallet jack

3. Walkie stacker
a)Manual walkie stacker
b)Powered walkie stacker

4. Pallet truck

5. Platform truck
a)Walkie platform truck
b)Rider platform truck

6. Counterbalanced lift truck (forklift)
a)Sit-down counterbalanced lift truck
b)Stand-up counterbalanced lift truck

7. Order picker

8. Tractor-trailer

Materials handling in spinning mills

Materials handling in a spinning mill broadly involves handling of raw material, intermediate products, wastes, finished goods, stores and maintenance equipment/tools. During fibre to yarn conversion, materials (raw material, laps, sliver, roving, yarn, finished goods and wastes) are stored at different places and transported between departments. Like any other manufacturing industry, spinning mills also require efficient materials handling system.

Raw material
Spinning mills receive raw materials – both cotton and man-made fibres – normally in the form of bales, in lorries. In the case of cotton, a bale weighs about 170 kg whereas a synthetic fibre bale weighs around 300 kg. On arrival, these bales are first stored in godowns, up to 10 feet height, in multiple layers, ie, one above the other and then transported to the mixing department.

In many mills, after arrival of lorries, bales are manually pushed down on the floor. Then, using single bale trolleys (Figure 1), the bales are taken to the godown one by one for storage. This is not only time consuming and requires more workers to be engaged but also laborious.

Figure 1. Single bale trolley

Forklifts, stackers, platform trucks and dock levellers
Forklifts (Figures 2 and 3) can be used to unload bales (2 or 3 at a time) directly from lorries, transport and stack them in godowns. Wherever required, suitable ramps must be constructed or dock levellers must be used (Figure 4) for unloading of bales by forklifts from lorries.

If there is any space constraint in the godown for free movement of forklift, electric stackers (Figure 5) can be used for stacking the bales. Mills, which normally handle large number of bales can use forklifts exclusively for unloading bales from lorries and transporting them to the godown and stackers can be used to stack the bales.

Figure 2. Forklift truck

Figure 3. Forklift truck with bale clamps

Figure 4. Dock leveller

From godowns, bales are manually transported to the mixing department (using single bale trolley). Instead, mills can use platform trucks (Figure 6), by which a single operator can transport up to 3 bales at a time and deliver them at the appropriate place in the mixing department.

Mills in which mixing department is situated at an elevated place, can use forklifts to supply bales from platform truck to the mixing area.

Mixing and blow room

To supply bales near bale plucker mills can use platform trucks. In the case of stack mixing, material from bins is carried either in hands or by using bamboo baskets/plastic crates and fed to bale openers. These methods not only consume more time but would also often result in spilling of the material on the floor leading to poor house keeping and more waste. Use of lift able spring type pedal operated mixing trolley (Figure 7) would help to eliminate these disadvantages. This type of trolley can transport up to 30 kg of material at a time. Moreover, the material can be fed evenly on the long lattices of the bale openers.

Many mills have been using trolleys to transport blow room laps to carding section. However, in some mills laps are transported by the workers keeping one lap at a time on the shoulder.

The trolley shown in Figure 8 can be used to transport 4 to 6 laps at a time. There is little possibility of any damage occurring to the laps since they are already stacked vertically in blow room. For better handling, each lap (after doffing) must be covered with synthetic or cotton cloth.

Sliver cans

Sliver cans – both full and empty – are to be transported between cards, draw frames, comber preparatory machines, combers and fly frames. In many mills, cans are transported manually by dragging them on the floor. This practice would not only spoil the floor, damage the can and result in wastage of sliver but also consume more time. The trolley shown in Figure 9 can be used to carry 3 or 4 cans at a time.

For easy transportation, cans fitted with casters are used in modern cards, draw frames and combers. Figure 10 shows the diagram of a single can trolley. Whenever there is a requirement for single can and/or space constraint in the department for the movement of multi can trolley, single can trolley can be used.

Comber preparatory machine laps

The laps are generally transported to the combers manually, ie by carrying one or two laps on hands at a time. This system takes a lot of time and also results in wastage of material. The trolley shown in Figure 11 can transport 8 laps at a time. It can be moved easily along narrow alleys.

Fly frame bobbins

During doffing, doffers normally keep the doffed bobbins on the top arms and then carry 8 to 10 bobbins by hand to the storage place. This practice is not only laborious but also sometimes results in bobbins falling on the floor and the roving material getting spoiled. Since a full bobbin weighs more than 1 kg, falling bobbins may also cause injuries to the workers.

The trolley shown in Figure 12 will be more suitable for storing full bobbins during doffing. This trolley can be moved in between fly frames and up to 60 bobbins (30 on each side) can be stacked easily. Empty bobbins required for doffing can also be placed on the top portion of this trolley. If sufficient number of trolleys are available, they (with full bobbins) can be shifted directly to the ring frame section. This will reduce unnecessary material handling and avoid storing of full bobbins in racks.

In many mills, after doffing, full bobbins are stored in racks from which they are transported to the ring frame section by using either a box type or open type trolley. In the box type trolley, bobbins are haphazardly stacked. This often causes damages to roving. In the open type trolley, bobbins are arranged neatly one over the other. This trolley has a capacity to transport all the bobbins from a single doff and it can be moved in narrow alleys also. However, in this type of trolley also, there are chances for the roving of bobbins stacked in the bottom row getting distorted.

The most appropriate trolley for carrying full bobbins to ring frames without causing any damage to the roving, is porcupine type trolley (Figure 13). In this type of trolley, each bobbin is placed separately on a peg.

Ring frame cops

Two different methods of doffing are being practiced by the mills.
  1. Doffing and donning by separate workers
  2. Doffing and donning simultaneously by the same worker

The latter is the correct method which is presently followed by a large number of mills. For practicing this method of doffing, mills must use suitably designed light weight trolleys. The doffing trolley suggested for simultaneous ‘doffing and donning’ method is shown in Figure 14. The trolley has two compartments; one for carrying empty cops and another for keeping doffed cops. Plastic crates can be fitted in the compartments. Each doffer must be given one trolley.

In some mills, doffed cops are first transferred to bamboo baskets or big size metal or wooden containers and they are transported to post spinning department in trolleys. The baskets/containers with doffed cops are kept one above the other on the trolley. This practice not only results in damages to some cops (top layer of yarns) but also causes entanglement leading to yarn waste. In winding department, the tenter has to transfer the cops from these containers/baskets either to bins or to other small containers. This would also result in entanglement of yarn leading to more waste.

Instead of transferring the doffed cops to the baskets, the plastic crates, which are used for doffing, with cops themselves can be loaded on the trolley and transported to the post spinning section.

Post spinning

In many mills, full cones are transported to the packing section by using baskets/box type trolleys. This method would cause damages to the cones. To avoid this, mills must use trolleys fitted with cone holder pegs (Figure 15). When the cones are kept in this trolley, it is easy to inspect them for package defects. This trolley can also be used to transport cheeses from doubler winding machines to TFO twisting/ring doubling.

Packing

In many mills, packed cone bags or cartons are transported to finished yarn go down by carrying them manually. Instead, a platform truck (Figure 6) can be used. For stacking bags or cartons in go downs and loading them in lorries/containers, electric stackers (Figure 5) can be used.

For moving pallets to storage place and loading them in containers, either manual pallet truck (Figure 16) or powered pallet truck (Figure 17) can be used.

Stores

Mills in which stores and spares are stored in racks, electric order picker (Figure 18) can be used to pick the required items.

Acknowledgements

The authors wish to place on record their grateful thanks to various suppliers and manufacturers of materials handling equipment for furnishing the required information. They express their sincere thanks to Dr Arindam Basu, Director, SITRA and Ms Indra Doraiswamy, Advisor, SITRA for their guidance in this work. Last but not the least, thanks are also due to Mr S Raj Kumar of L&C Division for drawing the diagrams of different materials handling equipment.

References:

1. Ratnam T V and Chellamani
    K P (2004): Maintenance Management in Spinning,
    SITRA Manograph.

2. Information on materials handling equipment provided by the manufacturers/suppliers.

The authors are with the The South India Textile Research Association (SITRA), Coimbatore.

published July , 2008
 
Reader Comments
 
Tamilselvi  |  7/19/2010 10:37:06 AM
good..
 
rajeev  |  5/9/2010 5:06:25 PM
all figure are not there. pl reload again for full use of same. thanks
 
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