A kind of polymer powder mixed material and preparation method thereof

Abstract

The invention provides a method for preparing a polymer powder mixed material, which comprises the following steps: the new powder of the polymer powder material and the remaining powder of the polymer powder material after sintering are mixed according to the ratio of 0-50%: 50-100%. The mass percentage is added to the powder mixing barrel, and the high-temperature and slow-speed stirring process is adopted to eliminate the static electricity between the polymer powders, and then the high-speed stirring process is used to sieve to obtain a polymer powder mixed material. The polymer powder mixed material of the present invention has good fluidity, high loose packing density of the powder, no orange peel in the sintered part, good surface quality, and high recyclability of the residual powder of the polymer powder material, which greatly reduces the cost and greatly reduces the cost. The environment is friendly.

Description

technical field [0001] The invention belongs to the technical field of additive manufacturing, and in particular relates to a polymer powder mixed material and a preparation method thereof. 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. This method is mainly accomplished using thermoplastic polymers, and patents US6136948 and WO9606881 describe in detail the method of using powdered polymers to manufacture three-dimensional objects. The technology has applications in aerospace, medical, footwear, industrial design and architecture, among other fields. [0003] In the selective laser sintering process, in the sintering package after the final sintering, a part of the powder...

AI Technical Summary

Problems solved by technology

[0004] In the actual selective laser sintering process, the reason why the remaining powder cannot be completely reused is mainly because the crosslinking between the powder and the powder will make the powder fluidity worse and the bulk density of the powder will be lower, so that the powder in the powder coating At this time, the powder on the powder bed is not dense enough. After the powder absorbs the laser energy, the voids in the melt are high, and the shrinkage of different sintered layers is inconsistent during crystallization, resulting in orange peel on the sintered part.

In order to ensure the quality of sintered parts when using selective laser sintering, a certain proportion of residual powder will be mixed with new powder according to the existing technology, but the amount of new powder required is significantly higher than the amount consumed by sintered parts, so , the amount of residual powder will continue to increase with the increase in the number of sintering times; in practical applications, ordinary stirring methods are usually adopted when mixing new powder of polymer powder materials and residual powder of polymer powder materials, and the stirring speed Low, although the residual powder of the polymer powder material is not directly sintered in the sintering process, it is more or less affected by a certain high temperature, the residual powder of the polymer powder material is bonded, and the new powder of the polymer powder material The powder mixed with the residual powder of the polymer powder material has low bulk density and poor fluidity, and the sintered parts are also prone to orange peel phenomenon, which cannot guarantee the quality of the sintered parts. On the other hand, it is necessary to add more The new powder of polymer powder materials reduces the addition of residual powder of polymer powder materials, and the utilization rate of residual powder of polymer powder materials is extremely low. However, the residual powder of polymer powder materials cannot be used in other manufacturing processes, resulting in The waste of this part of the surplus powder greatly increases the cost and pollutes the environment at the same time.