Graphite products from raw material preparation to finished product packaging have a strict process, the quality control of each link is directly related to the performance of graphite products. Today we take a look at the whole process of graphite products production and each process of quality control points.
The first step is to prepare high quality raw materials. Choose natural graphite or artificial graphite, need to check its composition ratio, impurity content and other quality indicators. Only high-quality graphite raw materials can sinter graphite products with excellent performance. The quality of natural graphite refers to the national standard, while the formula and composition ratio of artificial graphite need to be strictly controlled.
The second step is to pulverize the graphite, generally should be crushed to more than 45 mesh fineness. Crushing should be uniform, fine particle size is conducive to subsequent sintering, while coarse particles will affect the sintering quality. So the end of crushing to check the graphite powder particle size distribution, whether it meets the standard.
The third step is to mix the ingredients according to the design formula. The proportion of various raw materials directly affects the performance of graphite products, so it must be strictly in accordance with the specified proportion of stable measurement and mixing. Mixing to ensure uniformity and consistency, test the indicators of the mixture.
The fourth step is the mixture of compression molding. The use of mechanical pressure molding or mold molding, control the pressure parameters and time. After molding should be dried to remove the liquid in the mixture, at the same time can not be dried too fast to cause cracking of the product.
Next is the key sintering link. Sintering should strictly control the temperature and time parameters to ensure that the binder is completely softened sintering. Before the end of the session to check the sintering effect. If the sintering is not complete, it will affect the mechanical properties.
After the products are cooled down, they are cut, polished and other surface treatments to meet the requirements of profiling and appearance quality. Finally, each graphite product is tested for size and performance, and then packaged and shipped after passing the test.
From the above process flow, graphite products are mainly produced in the quality of raw materials, proportion of ingredients, molding parameters, sintering process of several aspects of strict control. The following key processes on the quality control points to do a specific analysis.
1, graphite raw material quality control
Whether you choose natural graphite or artificial graphite, you must ensure that its chemical composition meets the standard. Natural graphite check its graphite content, ash, volatile matter and other indicators. Artificial graphite must be strictly weighed according to the design formula of the proportion of each component ……
2、Quality control of ingredient mixing
The graphite powder, binder and lubricant in the mixed raw materials must be weighed accurately, and the quality share of each raw material should be controlled. Mixing to ensure uniformity, to avoid lumps. After the end of the mixing sampling test ratios, to ensure that the composition of the standard preparation ……
3, molding quality control
Molding pressure and time control directly affect the specific gravity and strength of the product. Too much pressure will cause internal micro-cracks, too long a time is not good. Technicians should strictly implement the process procedures, control the molding parameters ……
4、Sintering quality control
Sintering links need to develop a strict sintering curve, control the rate of heating and holding time to ensure that the binder is completely softened sintering. At the same time to prevent excessive sintering lead to graphite oxidation. Sampling before the end of sintering, if necessary, need to adjust the sintering system ……
Through the quality control of the whole production process of graphite products, it can be ensured that the composition ratio, internal structure and performance index of graphite material fully meet the design requirements. Strict quality control can reduce the failure rate of products and improve the stability of graphite products.
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