What's The Kind of Forming Cloth for Cylinder Mould Paper Machine?

Cylinder mould cover is an important component of the forming device on paper machines. It is driven by rollers or other transmission rollers to continuously filter and dehydrate pulp on the web, forming a wet paper layer, and transporting the wet paper layer to the rollers. In addition, the papermaking fabric also has the function of rotating various rollers that pull the wire part. Therefore, the water filtration performance of the papermaking fabric must be suitable for the requirements of papermaking; Capable of withstanding significant tension; Has the toughness and wear resistance of repeated bending and stretching.

There are two types of forming fabric for cylinder mould: metal mesh (mainly stainless steel wire mesh) and plastic mesh.

Stainless Steel Wire Mesh

1. Specification and Wire of Stainless Steel Wire Mesh

The specifications of stainless steel mesh refer to the mesh size (i.e. mesh number) and weft density. Mesh refers to the number of warp threads (ss wires that run through the longitudinal length of ss mesh) or the number of mesh holes within a width of 25.4mm (per inch) parallel to the weft threads. It is also represented by the number of meridians per centimeter width. Weft density refers to the number of parallel parallels (ss wires that run through the entire width of the ss mesh) per inch of width parallel to the longitude. In general, the latitude density is 60% -70% of the mesh size. Paper machines with high speeds use mesh with high weft density.

Stainless steel mesh is woven by arranging steel wires according to latitude and longitude lines. The vertical direction is called longitude, and the horizontal direction is called latitude. During the operation of stainless steel mesh, the forces and operating states of warp and weft are different, so the material composition of warp and weft is also different. Stainless steel mesh warp threads on circular paper machines are required to have high tensile strength, bending force, wear resistance, resistance to elongation, and acid and alkali resistance. The latitude lines are required to have appropriate curvature and straightness. This is because during the operation of the ss mesh, the warp is subjected to considerable tension, causing the weft to bend, and the width of the stainless steel mesh tends to shrink. If the tension of the warp is uneven, wrinkles will occur, so thicker steel wires must be used as weft.

2. Types of Stainless Steel Mesh

Stainless steel mesh can generally be divided into three types: single woven mesh, double wire mesh, and twisted mesh.

Types of Stainless Steel Wire Mesh

(1) Single woven mesh (single wire mesh). Single weave mesh can be divided into plain weave mesh and diagonal weave mesh. Single weave plain weave mesh is made by crossing a single warp and a single weft, that is, adjacent two warp threads pass through the upper and lower parts of the same weft, and the spacing between the warp threads is consistent. The difference between twill mesh and plain weave mesh is that the warp and weft threads of twill mesh are interwoven through two weft threads or the same surface of the warp threads, and this type of mesh has obvious diagonal twills. The characteristic of a half diagonal mesh (also known as a three line diagonal mesh) is that the warp passes alternately from the lower part of two weft threads and the upper part of one weft thread. Due to the larger contact surface between diagonal and semi diagonal nets and the rollers of the paper machine compared to single woven nets, their lifespan is longer.

(2) Double wire mesh includes double wire mesh and triple wire mesh, which are generally woven with thinner stainless steel wire. Double line mesh is woven from two warp threads and one weft thread, with the two warp threads intersecting vertically in the direction of the weft thread. A three wire mesh (also known as a three warp mesh, three woven mesh, or patterned mesh) is made by crossing three warp threads and one weft thread in groups. The middle meridian of each group intersects with the two meridians on both sides through a parallel. Double wire mesh is often used to make fine and smooth paper.

(3) Twisted mesh can be divided into single twisted mesh and double twisted mesh. Single twisted mesh refers to a mesh that only uses twisted threads on the warp. Double twisted mesh uses twisted threads for both warp and weft. Twisted wire is made by winding 5-7 copper wires around a metal core and twisting them together. Twisted threads have greater flexibility, so the lifespan of double twisted mesh is longer than that of single twisted mesh. Twisted mesh is commonly used on pulp and cardboard machines. Stainless steel mesh is welded at both ends to form an endless mesh ring.

From the perspective of water filtration performance, single weave plain weave mesh is better, followed by single weave semi diagonal weave mesh, single weave diagonal weave mesh is even worse, and triple weave mesh is the worst. From the network marks of the finished paper, the three warp net and diagonal net are lighter, followed by the single weave net, and the twisted weave net is the worst.

Polyester Mesh

The forming polyester mesh is a single filament mesh, with uniform strips, consistent orientation, and stable physical properties.   Endless polyester mesh, also known as endless mesh, is a type of circular mesh woven directly from a loom. Its characteristic is that the elongation of the net and the reduction of the fabric width are very small during operation. It can be produced using a ss mesh loom. First, weave it into a single piece, and then plug the two ends of the mesh together with a certain width to form a plug-in mesh with joints. Its advantage is that it can adapt to complex and variable lengths, but its disadvantage is that it is prone to deformation during operation.