钕铁硼粉末布粉堆积密度研究及工艺参数优化

Study on bulk density of NdFeB powder fillingprocess and optimization of process parameters

为提高钕铁硼粉末布粉堆积密度,采用离散单元法建立钕铁硼粉末布粉过程离散元模型,分析不同布粉工艺参数对型腔内粉体堆积密度的影响程度,利用响应面法对布粉工艺参数进行设计并进行试验验证。结果表明:在布粉过程中,钕铁硼粉末呈“鼻流”状堆积,堆积状态受到料盒与下模冲的共同影响;布粉工艺参数对堆积密度的影响程度从大到小依次为料盒往复速度、装粉高度、下模冲速度。最优布粉工艺参数组合为:料盒往复速度401 mm/s、装粉高度4.53 mm、下模冲速度23.9 mm/s,堆积密度平均值3.919 g/cm 3。

In order to improve powder bulk density of NdFeB,discrete element model of NdFeB powder filling process was established by discrete element method,and the influence of different process parameters on the density of powder deposition in the cavity was analyzed,the response surface method was used to design and verify the process parameters of powder filling.Results show that the NdFeB powder is deposited in the shape of“nose flow”in the process of powder filling,and the deposited state is jointly affected by the material box and the lower die punching.The influence degree of the powder distribution process parameters on the bulk density is the reciprocating speed of the material box,the height of the powder filling,and the punching speed of the lower die,going from large to small.The optimal combination of powder process parameters is:reciprocating speed of the material box 401 mm/s,filling height 4.53 mm,punching speed of the lower die 23.9 mm/s,and average bulk density 3.919g/cm 3.