Molded graphite is produced by mold pressing machine. And isostatic graphite is produce by isostatic pressing machine. The two kinds of graphite is different. They have their own characteristics. But Mold pressing machine has its limitations for production. Details as bellow:
- Tonnage limitation.
With a diameter of 1500 mm, for example, if the compression unit pressure is 100 MPa, the compression working pressure will be 1766215t, the design tonnage will be higher. While manufacturing such a high tonnage of the pressing machine is not difficult, but with the length increases, the pressing machine will be a big size monster, and Cost is will be very high.
- Product height restrictions
As far as I know, the current double-sided suppression of molded products, the height can only be between 300 ~ 400mm, if the product height is of 2000mm, under normal circumstances, the slider and the machine bed height and weight ratio is 4: 1, then the press space will reach 8000mm. Although we can change the structure of the pressing machine and die, expecting to reduce some of the height, but the pressing machine’s design and manufacture will encounter great difficulties. Moreover, such a high product, Its bulk density difference will be very obvious. And may cause the centre part of the state cannot be formed.
3 Limits of roasting/baking
The statistical data shows that the unqualified products of carbon graphite products, is caused from the roasting process, with more than 70%. The main form of waste product is internal or external cracks. There are many reasons for the cracks, such as the rationality of the raw materials, binder, the unit pressure, the speed of the baking temperature, the degree of uniformity of the product heat, the “oxygen leaching” of the baking process, the nature of the filler and so on, but its undeniable that the uneven of the product density is the main reasin for Structural defects. This is because that different bulk density caused different expansion coefficient, and it will have differences in the roasting process, will produce unbalanced internal stress. When the internal stress exceeds the strength of the product itself, Cracks appears due to the release of internal stress, which is not only generated during the baking process but is also liable to occur during the cooling process. As a result, the isostatic press forming products, as described above, to a large extent, its bulk density is even, Not only in the same product size, the possibility of product cracking is reduced, but also the production of large-scale products possible. In addition to above, we can produce isostatic pressing graphite special-shape, not only round and Sheet. More importantly, the product performance and product size has nothing in relation.
CFCCARBON LTD can produce large amount of isostatic graphite with stable and reliable quality, Our Products were sold throughout the country and exported to Europe, America, Southeast Asia and other countries and regions which enjoy a high reputation all over the world.
All sizes available, standard bulk density: 1.78g/cm3; 1.85g/cm3; 1.91g/cm3.
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