The forming section consists of a long moving belt of fine mesh screen supported by rolls or foils. For many decades, this screen belt was made of bronze and called the " wire." Today it is made of synthetic polymer — primarily polyester monofilament — and is called the forming fabric. Newer machines (gap formers) trap the slurry out of the slice between two forming fabrics. As the forming fabric moves along the forming section, water drainage is assisted by foils. The fiber then passes over the suction boxes to pull more water from the furnish. Still more water is removed at the couch roll just before the sheet leaves the forming section. At this point, the sheet consistency is about 20%.

 

Dedicated research has produced synthetic forming fabrics that yield improved drainage, higher production and longer life at a lower cost per ton of paper produced.

 

Keylife's forming fabrics are available in a wide variety of meshes, depending on the type of paper produced. Coarse mesh fabrics are used to manufacture heavy paper grades such as those used in the production of corrugated boxes. Very fine mesh fabrics are required for lightweight paper, such as writing paper, book paper and magazine paper. The average life span of a forming fabric, depending on the type of paper, is approximately three months.

 

Keylife 2.5 layer forming fabric is an established double layer forming fabric family with qualities for all paper grades. It is available in 8 and 16 shaft designs with or without extra support strands on the paper side. The excellent raw material, which has the dimensional stability and abrasion resistance, is used to promote increased life potential and reduced energy consumption.

 

Two and a half layer forming fabric is a 8/16-shed,double and a half layer wire. This wire has an 8-shed weave with additional transverse strands, knows as support strands, on the paper side. With this design, a good sheet support, high evenness and good retention can be provided. At the same time, the wire has 16-shed big span weave on the back side and the bottom weft uses a coarse yarn to improve running life.

 

This 2.5 layer design brings a high dewatering capacity and stability in both MD and CD.

 

The two and a half layer forming fabric impresses with its excellent formation and low energy consumption. The user-friendly design facilitates efficient operation.

 

In the paper machine, fabric and felt merge over the forming roll, compressing the suspension and initiating drainage. The drainage is carried via channels through a de-aeration device into a cyclone system (Vk>1,200 m/min) and then back to the white water tank. In the process, the 2.5 layer forming fabric achieves outstanding formation results.