基于图像法的刨花板钻孔粉尘尺寸和形态分布研究

排钻开孔是板式家具生产中的一个关键环节,但排钻设备多数没有固定吸气罩,加工过程中产生的木粉尘难以收集,由此带来显著的环境影响。笔者采用图像法对刨花板排钻开孔加工过程中产生的粉尘进行尺寸和形态分析,讨论了粒度、粒形参数对粉尘流动性的影响,为排钻粉尘的有效治理提供基础数据。试验表明,排钻粉尘颗粒的尺寸分布较广,但多数粉尘的粒径小于100 μm,属于总悬浮颗粒物范畴,它们在空气中停留的时间较长,传播距离也因此较远。横纵比、圆度和凸度分析表明,排钻粉尘的形态随尺寸变化而产生显著差异,大颗粒总体上形态较不规则,而小颗粒则较为规整。排钻粉尘在产生、排屑和传播过程中相互碰撞和磨蚀是形成这种形态分布特征的主要原因。在收集和输送过程中,大颗粒排钻粉尘因形态不规则而容易相互接触咬合,并在颗粒间形成较多孔隙,小颗粒的形态特征虽然有利于流动,但相互间易发生团聚,当其填充在大颗粒间的孔隙时,流动性受到进一步限制,因而总体上看排钻粉尘的流动性较差。
Panel drilling is a key operation in the manufacturing of particleboard furniture. The dust emitted from this process is hard to collect due to the absence of dust collecting hood in the machine, resulting in the increased environmental concerns. In this study, the size and shape distribution of dust emitted from particleboard drilling was investigated by image analysis, and their effect on dust flowability was discussed. We aimed at providing the efficient dust collecting with data supports. The results showed that the dust sizes emitted from the drilling process were widely distributed. But most ISO area diameters of the particles were below 100 μm, making them fall into the category of total suspended particulates(TSP). The TSP can stay longer in the air and travel in a wider space, which is considered harmful to human health. The distribution of the aspect ratio, roundness and convexity showed that the dust shape changed significantly with the size change. The bigger particles exhibited more irregularity, while the smaller ones presented more homogeneous shape. This pattern was established by the collision and erosion among the particles during their generation and removal from the cutter and transmission in the air. With respect to dust collecting and conveying, bigger particles tended to interlock with each other, making them hard to move and leaving many voids between them. The smaller particles were easy to agglomerate although their regular shape indicated a good flowability. Besides, when falling into the inter-particle voids, their flowability was further restricted by the surrounding walls. It was therefore concluded that the overall flowability of the dust emitted from particleboard drilling was poor