A preparation method for controlling polyamide powder melt flow index

Abstract

The invention provides a preparation method for controlling the melt flow index of polyamide powder, by adding polyamide resin, solvent and additives into a closed high-pressure reaction kettle, filling in an inert gas protection, continuously stirring and heating to a polyamide temperature. The amide resin is completely dissolved in the solvent, continue to heat up to the reaction temperature and keep it warm for a period of time, then cool down to room temperature, suction filter, and dry to obtain polyamide powder; wherein, by increasing the reaction temperature and the time during the reaction process higher than the dissolution temperature, Improve the melt flow index of polyamide powder. The present invention adopts the method to reduce the molecular weight of the polyamide powder during the preparation process of the polyamide powder, thereby increasing the melt flow index of the polyamide powder and improving the processing performance of the powder in the selective laser sintering process, so that the polyamide powder has More excellent melt fluidity, reducing internal defects of parts, improving the mechanical and mechanical properties of parts, improving the surface quality of parts and improving the reusability of polyamide powder.

Description

technical field [0001] The invention belongs to the technical field of additive manufacturing, and in particular relates to a preparation method for controlling the melt flow index of polyamide powder. Background technique [0002] Selective laser sintering is a method of manufacturing three-dimensional objects by selectively fusing multiple layers of powder, which allows machining without tools but only by laser sintering multiple overlapping layers of powder according to the three-dimensional image of the object to be produced, to get a 3D solid. [0003] Selective laser sintering technology can prepare products with any complex structure within the size range, which is very effective for sample design, testing and even small batch manufacturing in the production process during the research and development process, but this manufacturing method will bring precision compared to traditional processes In many fields, users are very concerned about the surface quality and mec...

AI Technical Summary

Problems solved by technology

[0004] Polyamide powder is one of the main raw materials for selective laser sintering technology to manufacture three-dimensional objects. However, the selective laser sintering of polyamide powder in actual production often has poor surface quality and low reusability, which affects the appearance and One of the reasons for this problem is that the melt flow index of polyamide powder is low

In the selective laser sintering process, the time interval between laser scanning and the next layer of powder coating is short. If the polyamide powder melt flow index is too low, the melt fluidity will be poor, and it will not be fully leveled, which will affect the workpiece. The internal compactness leads to a decrease in mechanical properties; due to insufficient melt fluidity, the part will shrink unevenly during the cooling process, resulting in poor surface quality of the part; at the same time, when the remaining powder is used again, the flow index of the powder melt is further reduced. The mechanical properties and surface quality of the parts will be further deteriorated

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