There are various forming methods for carbon production, including four main methods: compression molding, extrusion molding, vibration molding, and isostatic pressing molding.

Molding method

This method uses a vertical press to make a mold according to the shape and size of the product. Then, a certain amount of mixed paste or powder is loaded into the mold on the press workbench. The press is started to apply pressure to the paste or powder, and maintained for a certain time to form it. Then, the pressed blank is ejected from the mold.

The molding method can be divided into unidirectional pressing and bidirectional pressing, hot pressing and cold pressing according to different processes and equipment conditions. The molding method is suitable for pressing products with small size differences in three directions, uniform density, and high structural density and strength, but the products have anisotropy. Mainly used for producing electric carbon products and special graphite products.

Extrusion forming method

The extrusion method uses a horizontal extruder, which first loads the paste into the material chamber of the press and applies pressure to the paste using the main plunger of the press. First, pre press, then apply pressure to squeeze the paste out through a nozzle installed in front of the material chamber that matches the cross-sectional shape and size of the product. Then, cut it off with a cutting knife according to the required length, which is the extruded green billet.

The extrusion method is suitable for larger bars, pipes, or other shaped products. The extrusion method can produce continuously, with high production efficiency, simple operation, and high degree of mechanization. But the volume density and mechanical strength of the product are low, and it has anisotropy. Mainly used for producing graphitized electrodes, carbon electrodes, and carbon blocks.

Vibration forming method

Vibration forming is the process of loading the paste into a mold placed on the vibration table of a vibration forming machine, and then placing a heavy hammer on top of it. By utilizing the high-speed vibration of the vibration table, the paste is compacted and formed.

The vibration forming machine has a simple structure. As long as a small forming pressure is applied to the paste, it can produce larger sized products, especially suitable for producing thick and short products with similar dimensions in the length, width, and thickness directions, as well as some irregular products. For example, pre baked anodes, cathodes, carbon blocks, and large or oversized carbon electrodes and crucibles.

Isostatic pressing forming method

Isostatic pressing forming is completed in an isostatic pressing pressure vessel. It places the pressure powder into an elastic mold made of rubber or plastic, seals it, and puts it into a high-pressure vessel. An ultra-high pressure pump is used to inject high-pressure liquid medium (oil or water), causing the pressure powder to form under pressure. There are two types of isostatic pressing forming: cold isostatic pressing forming and hot isostatic pressing forming.

Isostatic pressing can produce isotropic and anisotropic products, with a uniform structure, particularly high density and strength. Generally used for producing special graphite, especially for producing large-sized special graphite products.