Abstract

Occupational exposure during metal additive manufacturing (Laser Powder Bed Fusion) using an aluminum alloy (AlSi10Mg) was assessed. Background aerosols before manufacturing, powder sieving, machine loading, manufacturing, machine unloading, powder unpacking, and machine cleaning were analyzed. Measurements were taken simultaneously at the source, in the near field, and on the operator during five manufacturing cycles. Aerosol measurement devices and physico-chemical techniques were used to determine the particle number or mass concentration (DiSCmini, core particle counter and sampling cassette), particle size distribution (NanoScan, optical particle detector and impactor), and the shape/size and chemical compositions of the inhalable particles (laser diffraction, inductively coupled plasma spectroscopy, scanning electron microscopy, energy dispersive X-ray microanalysis, and Brunauer–Emmett–Teller Method). The laser powder-bed fusion machine emitted in the additive manufacturing room an inhalable fraction of 2.37 ± 0.35 mg/m³, with an aerosol number concentration ranging from 2 × 10⁴ to 10⁵ #/cm³ and a mass mean aerodynamic diameter of 318 nm. A relatively low concentration level was observed in the near field of the machine with an aerosol number concentration of ∼10⁴ #/cm³. A higher concentration level on the operator was attained during the unpacking and cleaning steps, showing an inhalable fraction of 1.73 ± 0.30 mg/m³. Al and Mg nanoparticles were aerosolized at the source (inside the laser powder-bed fusion machine) with a particle size distribution of 153 nm for Al and 117 nm for Mg and an aerosol number concentration reaching ten times that of the background aerosol level. The number or mass concentration of particles in the room atmosphere was increased to double that of the background aerosol level at specific workstations during manufacturing. Metal additive manufacturing is a source of potential occupational exposure to airborne metal nanoparticles. Particle-counting instruments showed high numbers of nanoparticles and some important peaks of particles ranging from 10 nm to 10 µm or larger at specific work tasks in the Additive Manufacturing (AM) environment. A multimetric approach was used to characterize the particle emissions resulting from this type of additive manufacturing.

摘要

对使用铝合金 (AlSi10Mg) 的金属增材制造（激光粉末床融合）过程中的职业暴露进行了评估。对制造、粉末筛分、机器装载、制造、机器卸载、粉末拆包和机器清洁之前的背景气溶胶进行了分析。在五个制造周期中，在源头、近场和操作员身上同时进行测量。使用气溶胶测量设备和物理化学技术来确定颗粒数量或质量浓度（DiSCmini、核心颗粒计数器和采样盒）、颗粒尺寸分布（NanoScan、光学颗粒探测器和撞击器）以及形状/尺寸和化学成分可吸入颗粒的分析（激光衍射、电感耦合等离子体光谱、扫描电子显微镜、能量色散 X 射线微量分析和 Brunauer-Emmett-Teller 方法）。增材制造室激光粉床熔融机排放的可吸入分数为2.37±0.35mg/m ³，气溶胶数浓度范围为2×10 ⁴至10 ⁵ #/cm ³，质量平均空气动力学直径为318纳米。在机器近场观察到相对较低的浓度水平，气溶胶数浓度为~10 ⁴ #/cm ³。在拆包和清洁步骤中，操作员获得了更高的浓度水平，显示可吸入分数为 1.73 ± 0.30 mg/m ³。Al和Mg纳米粒子在源头（激光粉末床熔融机内）雾化，Al的粒径分布为153 nm，Mg的粒径分布为117 nm，气溶胶数浓度达到背景气溶胶水平的10倍。在制造过程中，房间大气中颗粒的数量或质量浓度增加到特定工作站背景气溶胶水平的两倍。金属增材制造是空气中金属纳米颗粒潜在职业接触的一个来源。在增材制造 (AM) 环境中的特定工作任务中，颗粒计数仪器显示出大量纳米颗粒和一些重要的颗粒峰值，范围从 10 nm 到 10 µm 或更大。使用多重测量方法来表征此类增材制造产生的颗粒排放。