A coating apparatus comprising: a coating unit, wherein the coating unit comprises a coating roller and a knife thereon, to apply a coating onto a substrate, wherein the knife further comprises: a sharp edged blade and a blunt edged blade which are selectable based on the type of coating application, wherein the coating unit is configured to provide: a knife on air (22(a)) coating application wherein the sharp edged blade is used for filling the pores of the substrate; and a knife on roll (22(b)) coating application wherein the blunt edged blade is used for applying a film on the surface of the substrate; a drying unit placed downstream with respect to the coating unit, wherein the drying unit comprises an insulated chamber for drying the coating applied to the substrate; a pressing unit placed downstream with respect to the drying unit, wherein the pressing unit comprises a pair of pressing rolls (42(a) and 42(b)) configured to press the substrate with the coating, and to apply a binding pressure on the substrate with the coating to obtain adhesion of the coating to the substrate, and wherein the pair of pressing rolls (42(a) and 42(b)) comprise a first pressing roll (42(a)) coated with hard chrome plating and a second pressing roll (42(b)) coated with rubber, and wherein the speed of the pair of pressing rolls (42(a) and 42(b)) is higher than the speed of the coating roller in order to maintain a tension on the substrate and control a moving speed of the substrate to achieve uniformity of the coating; and a control unit for controlling operations of the coating unit, the drying unit and the pressing unit, wherein the control unit is further configured to regulate a rolling speed of the coating roller and the pair of pressing rolls (42(a) and 42(b)), and a temperature of the drying unit. a coating unit, wherein the coating unit comprises a coating roller and a knife thereon, to apply a coating onto a substrate, wherein the knife further comprises: a sharp edged blade and a blunt edged blade which are selectable based on the type of coating application, wherein the coating unit is configured to provide: a knife on air (22(a)) coating application wherein the sharp edged blade is used for filling the pores of the substrate; and a knife on roll (22(b)) coating application wherein the blunt edged blade is used for applying a film on the surface of the substrate; a sharp edged blade and a blunt edged blade which are selectable based on the type of coating application, wherein the coating unit is configured to provide: a knife on air (22(a)) coating application wherein the sharp edged blade is used for filling the pores of the substrate; and a knife on roll (22(b)) coating application wherein the blunt edged blade is used for applying a film on the surface of the substrate; a knife on air (22(a)) coating application wherein the sharp edged blade is used for filling the pores of the substrate; and a knife on roll (22(b)) coating application wherein the blunt edged blade is used for applying a film on the surface of the substrate; a drying unit placed downstream with respect to the coating unit, wherein the drying unit comprises an insulated chamber for drying the coating applied to the substrate; a pressing unit placed downstream with respect to the drying unit, wherein the pressing unit comprises a pair of pressing rolls (42(a) and 42(b)) configured to press the substrate with the coating, and to apply a binding pressure on the substrate with the coating to obtain adhesion of the coating to the substrate, and wherein the pair of pressing rolls (42(a) and 42(b)) comprise a first pressing roll (42(a)) coated with hard chrome plating and a second pressing roll (42(b)) coated with rubber, and wherein the speed of the pair of pressing rolls (42(a) and 42(b)) is higher than the speed of the coating roller in order to maintain a tension on the substrate and control a moving speed of the substrate to achieve uniformity of the coating; and a control unit for controlling operations of the coating unit, the drying unit and the pressing unit, wherein the control unit is further configured to regulate a rolling speed of the coating roller and the pair of pressing rolls (42(a) and 42(b)), and a temperature of the drying unit.