Raw jute in the form of bales are processed in jute mills to produce hessian, sacking, jute yarn, bags, and other useful products. Raw jute bales from jute fields or suppliers, carried by trucks are unloaded are stacked in the jute mills gowdown.
In the selection process, raw jute bales are opened to find out any defect and to remove the defective portion from the mora by experienced workers.
Raw jute bales are of two types i.e. 150 kg weight and 180 kg weight with or without top portion cutting.
The bales are assorted according to end use like Hessiean weft, Sacking wrap, Sacking weft etc. After selection, jute bales are carried to softning section by workers called Gariwala and Bajawala.
In softning process jute morahs are made soft and pileable. Two methods are used for softning; use of softening machine and use of jute good spreader. Generally an emulsion plant with jute softner machine is used to lubricate and soften the bark and gummy raw jute.
The emulsion plant consists of gear pump, motor, vat, jet sprayer, nozzles, emulsion tank and the jacket. In this softning process jute becomes soft and pileable and suitable for carding.
Carding is a combining operation where jute reeds are splitted and extraneous matters are removed. Jute fibres are formed into ribbon called “sliver”. There are three different carding sections:
(i) breaker carding
(ii) Inner carding
(iii) finisher carding
In the Breaker carding machine soften jute after piling is feed by hand in suitable weight. The machine by action with different rollers turns out raw jute in the form of jute sliver for finisher carding. In this process root cutting is necessary before feeding the material to the hand feed breaker carding machine.
- Finisher carding machine make the sliver more uniform and regular in length and weight obtained from the Breaker carding machine.
- Finisher carding machine is identical to the Breaker carding machine, having more pair of rollers, staves, pinning arrangement and speed.
- Nearly 4 to 12 slivers obtained from Breaker carding machine is fed on this machine.
- The material thus obtained is send to drawing section.
Drawing is a process for reducing sliver width and thickness by simultaneously mixing 4 to 6 sliver together. There are three types of Drawing Frame machine. In most mills 3 Drawing passages are used in Hessian and 2 Drawing passages are used in Sacking.
The slivers obtained from finisher carding machine is fed with four slivers on to the first drawing frame machine. The first drawing frame machines makes blending, equalizing the sliver and doubling two or more slivers, level and provide quality and color. This machines includes delivery roller, pressing roller, retaining roller, faller screw sliders, check spring, back spring, crimpling box etc..
In second drawing, the Second Drawing Frame machine obtain the sliver from the First drawing machine and use six slivers and deliveries per head. The Second Drawing machine makes more uniform sliver and reduce the jute into a suitable size for third drawing.
In the third drawing, the Third Drawing frame machine uses the sliver from second drawing. The Third Drawing machine is of high speed makes the sliver more crimpled and suitable for spinning. The comparison of the three drawing process:
Spinning is the process for producing yarn from sliver obtained from Third drawing.
The jute spinning frame machine is fitted with slip draft zone and capable of producing quality yarns at high efficiency with auto-dofting arrangements also.
|Drawing Process||Efficiency Range(%)||Productivity Mt/mc/shift|
|1st Drawing||55 – 73||1.75 – 2.2|
|2nd Drawing||64 – 74||1.62 – 1.9|
|3rd Drawing||67 – 70||1.31 – 1.4|