The graphite rolling forming process is mainly used for pressing graphite sheets, graphite paper foils and other products.
This rolling method can press flexible graphite into graphite sheet without any binder. The whole process is carried out on special equipment equipped with roller rolling machine.
The structure of the roller compactor consists of: (1) a hopper containing vermicular graphite (2) a vibrating feeding device (3) a conveyor belt (4) four pressure rollers (5) a pair of heaters (6) a roller for controlling the thickness of the plate (7) ) embossing or patterning drum (8) and roll (9) cutting knife (10) finished roll
Working process: High-purity graphite enters the feeding device from the hopper and falls on the conveyor belt. After being rolled by the pressure roller, a material layer of a certain thickness is formed.
The heating device generates high temperature heating to remove the residual gas in the material layer and to expand the unexpanded graphite one last time. Then, the preliminarily formed graphite sheet is sent into a roller with a controlled thickness and size, and pressed again according to the specified size, so as to obtain a flat sheet with a uniform thickness and a certain density. Finally, after being cut by a cutter, the finished graphite sheet is rolled up.
The single-layer flat plate of the graphite plate is rolled, although the pressing plate is flat and smooth, but it should not be too thick. When the one-time molding is too thick, its uniformity and density are difficult to guarantee. In order to make a thick plate, a multi-layer veneer is stacked and pressed into a multi-layer composite plate.
Adhesive is added between each two layers and then rolled to form. After the graphite sheet is formed, it is heat treated to carbonize and harden the binder. The multi-layer flat rolling method is carried out on a multi-layer continuous rolling machine.
The working process of the multi-layer continuous rolling machine: the veneer is drawn out from the veneer winding roller, and the adhesive is coated on both sides by the adhesive coating roller. The gap is rolled to a certain thickness.
Then send it to the heater for heating and drying. The thickness of the graphite plate is controlled, and the thickness is adjusted to reach the specified size, and then sent to the roasting device for roasting. After the binder is carbonized, the pressure roller is used for final pressure forming.
The continuous rolling method can suppress the flexible graphite sheet with a thickness of 0.6~2mm, which is better than the single-layer rolling machine, but the thickness of the sheet will also bring the disadvantage of delamination of the graphite sheet, which brings trouble to the use.
The reason is that when the graphite plate is pressed, the gas escapes and stays in the middle of the interlayer, which prevents the close bonding between the layers. The way to improve is to solve the problem of exhaust gas in the pressing process of graphite plate.