Essay --

Manufacturing process of CLAY BRICKS Most bricks are formed by one of two basic processes. Extrusion Fairly stiffed texture is mixed with clay body which is loaded into extruder worm screw force it into a die through pushing it along a barrel .depending upon how much clay will shrink in drying and firing process the die is made larger considering this The clay emerges as a continuous brick shaped column. Initially this is smooth but it can be modified by removing a thin sliver from the top and sides using a taught wire to produce a ‘wiredrag’ effect or by placing textured rollers over the column to create a rusticated effect or even by blasting the column with sand. The clay column is then cut into single bricks and palletised ready for the dryers or in some factories, are loaded directly onto kiln cars. Extruded bricks can be solid but cannot be frogged & are generally perforated. Soft mud moulding Soft mud moulding Bricks are constituted in mould boxes through some number of processes . Many methods can be applied but all have a common theme. A mould release medium stops the clay from sticking to the box (sand, oil or water) when soft clay is thrown into a mould,. The bricks are turned out & the excess clay is stuck off from the top of the mould. This is done by hand by a craftsman who would create one brick at a moment. This is slow, expensive & labour intensive used In these days only for generating special shapes or decorative bricks. For standard bricks large automated machines can be replicated the hand-making procedure much quicker by taking use of banks of mould boxes on a circuit where the boxes are filled with pre sanded clots of clay, washed, sanded struck off level and the formed brick turned out.... ...re than 60 F/h by introducing steam standard weight is generally cured at 150-165 F , whereas light weight at 170-185F . After reaching curing temperature steam flow is shut down .blocks are then left for soak in moist hot air for 12 – 18 hours. After this block is left for drying by exhausting moist air and further increasing the temperature of kiln which took about 24 hours. 2) High pressure kiln pressure (autoclave) –temperature is generally higher about 300-375 F and pressure is 80-185 psi block is left to soak for 10 hours , pressure is then decreased rapidly , because of which trapped moisture of block is released quickly. It is more costly process but it takes less time. References http://www.madehow.com/Volume-3/Concrete-Block.html http://dcmsme.gov.in/reports/glass/HollowBricks.pdf http://www.ibstock.com/pdfs/technical-support/TIS16Howbricksaremade.pdf