LED FABRICATION

PAPER MANUFACTURINGS.Gurucharan(ME13B1031)Tushar meshram(ME13B1022)Pankaj Kumar(ME13B1027)

Wood(predominant) Preferred source: Coniferous trees such as spruce and fir. Reason: Cellulose fibers in the pulp of these species are longer, thereby making the paper stronger. Plants like bamboo, flax, jute, hemp.Remaining material: recycled newspapers, vegetable matter and recycled cloth

RAW MATERIALS

BLOCK DIAGRAMMAKING THE PULP

MECHANICAL PROCESS:Logs are tumbled in drums to remove the bark.

The wood is chipped down into small pieces by pressing it between two revolving stabs.

MAKING THE PULPCHEMICAL PROCESS:

The wood chips from the bark are fed into the digester and they are cooked in acid.

The lignin in the wood gets dissolved into the acid and the fibers get separated.

The fibers are washed to remove the acid. The pulp obtained is bleached and then dried.

Pulp is dissolved in excess of water and passed through rotating and stationary blades as it gives a clean cut or fibrillated ends.

Filler materials such as titanium oxide are added as they influence the physical, optical and aesthetic properties of the finished paper.

Sizings such as starch are added as they make the paper resistant to water based ink (ink actually sits on top of the paper rather than sinking in).REFININGPULP TO PAPER

Pulp is sprayed between two rollers thereby forming a sheet and removing water up to some extent.

For further removal of water, the sheet is pressed against water absorbing plates.

If paper is to receive a water mark, a device called dandy which contains the required impression and it moves across the sheet of pulp and presses a design into it.

PULP TO PAPERSheet is passed through soft metal rollers called calendars so as to make it more smooth, compact, and achieving uniform thickness. This process is called calendaring.

Starch and coating colors are sprayed on elastic rollers which transfers these chemicals uniformly on to the sheet which is passed between the rollers. Then the paper is run through extremely smooth rollers for last time. This process is called supercalendaring.

The finished product is rolled, packaged and transported.

FINISHINGRegulated wastes from the paper and pulp industry include air emissions and wastewater.

Air emissions include sulphur dioxide, nitrous oxide, chloroform and other particular matters which are harmful for environment.

Wastewater include chlorinated phenolics, dioxins and suspended sediments which are harmful for habitats near mills.

Around 100 liters of water is required for manufacturing 1 kg of paper which is really high. So the water levels necessary for fish are reduced.

ENVIRONMENTAL CONCERNSNormal trees have short fiber length. So genetic modifications can be made to it so that its fiber length can be increased and the lignin content can be modified.

Genetic modification allows easier delignification by using smaller amount of chemicals and yields more high-quality pulp.

Genetic modification reduces the pollutant chemicals thereby making the manufacturing process more environment friendly.GENETIC MODIFICATION

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