For the surface quality of paper burning paper machine, it is customary to divide the paper machine into long net, round net, clip net and long round net mixed models according to the type of paper shaper used; There are also cultural paper machines (including newsprint), paperboard machines (including packaging paper), toilet paper machines and special paper machines according to their main product varieties; Or according to the thickness of paper production, it can be divided into thin paper machine, paperboard machine and conventional paper machine

　　Multi process treatment is used to obtain good surface quality. Most paper is calendered by a mechanical calender after the paper machine to make the paper surface flat and consistent. The mechanical calender is made of several cold cast iron rollers, which flatten the paper surface with the self weight of each roller or another pressure. If a higher surface smoothness is required, it shall be calendered with a super calender. It is generally composed of paper meal roll and cold cast iron roll. According to different application requirements, some varieties need surface sizing to improve surface quality; Some have to go through surface coating to improve the appearance quality or printing quality. Surface sizing and coating can be processed outside the paper machine through the sizing machine and coating machine, or the sizing machine and coating equipment can be combined in the paper machine for in machine processing.