Method for coating grains

Abstract

The invention discloses a method for coating grains, which comprises the following steps: 1) putting fluid materials as coating agent on a working platform, respectively connecting the two ends of a grain with a rotator tool in a mode of dismountable connection, and putting the grain and the rotator tool on the working platform, wherein the maximum overall diameter of the rotator tool is greater than the overall diameter of the grain; 2) repeatedly rolling the grain and the rotator tool on the working platform so as to ensure that the surfaces of the grain required to be coated repeatedly pass through the fluid materials and are touched with the fluid materials until the coating agent are uniformly adhered to the surfaces of the grain required to be coated, controlling the thickness of a coating layer by a gap between the tool and the working platform; and 3) lifting the grain and the rotator tool, taking down the rotator tool, and putting the grain on a medicine-cooling rack to dry so as to complete the coating of the grain. The invention has the advantages of high production efficiency and easy operation, and the thickness, straightness and circular runout of the coating layer are meet the requirements for industry quality, and the coating materials are saved.

Description

technical field [0001] The invention relates to a method for coating a grain, especially a rocket propellant grain. Background technique [0002] With the improvement of the tactical performance requirements of the propellant for civilian rockets, in order to obtain a specific combustion law for the charge, the choice of the charge type alone can no longer achieve the goal, and a material that inhibits combustion is needed. In order to obtain a specific pressure-time, thrust-time curve, this kind of material that inhibits combustion is called a coating agent, and coating it on the surface of the grain is called a coating layer. In addition to controlling and adjusting the combustion surface area of ​​the charge, the cladding layer can also play a certain role in heat insulation, so that the propellant gas does not directly contact the shell, so the wall thickness of the engine can be appropriately reduced, and the weight of the engine can be reduced. At present, the coatin...

AI Technical Summary

Problems solved by technology

At present, the coating process of powder column can be divided into: spiral extrusion coating, casting coating, pressure bonding coating, winding coating, dipping coating and brushing coating, etc.; and the coating of fluid materials is now Casting coating and brushing are mainly used for coating. Casting coating is mainly used for coating of complex-shaped drug columns. The process is more complicated and the efficiency is low, while brushing coating is used for coating of simpler drug types. , such as cylindrical powder column, which is a purely manual operation method. Although the process is simple, the production efficiency varies greatly depending on the operator's proficiency. The general production efficiency is low, and the control of coating quality is mainly It is determined by the proficiency of the operator. The quality indicators of the coating layer mainly include: thickness, straightness, and circular runout. The control of the thickness of the coating layer is determined by the concentration and weight of the prepared coating agent. Therefore, the coating agent must be weighed before each set of powder coating, which is inconvenient to operate; the straightness index is controlled by manual operation, and an excess cylinder is needed for detection. According to the production situation over the years, manual The straightness of painting cannot reach the quality standard 100%; the degree of circular run-out varies greatly depending on the proficiency of the operator. The average pass rate after coating can only reach 40%, and the return rate is high; and because The outer diameter of the cladding layer cannot be controlled by manual operation, and the waste caused by throwing during manual operation leads to a high rate of useless consumption of cladding materials

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