کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
7173345 1464464 2018 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Laser powder bed fusion at sub-atmospheric pressures
ترجمه فارسی عنوان
ترکیب فیبر پودر لیزری در فشارهای زیر اتمسفر
کلمات کلیدی
تصویربرداری با سرعت بالا، ترکیب پودر پودر لیزری، فشار زیر اتمسفر، خلاء،
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی صنعتی و تولید
چکیده انگلیسی
The perceived advantages of laser powder bed fusion (PBF) at reduced pressure include a more stable melt pool and reduced porosity. In this study, high-speed imaging was used to investigate the interaction of the laser beam with the powder bed at sub-atmospheric pressures. At atmospheric pressure, the laser plume produces a flow in the ambient atmosphere that entrains particles toward the melt pool. As the pressure decreases, this hydrodynamic entrainment increases but eventually the expansion of the laser plume prevents the particles reaching the melt pool: profiles and cross-sections of the track reveal a drastic reduction in its cross-sectional area. As the pressure decreases further, into the molecular flow regime, particles are only repelled by the plume away from the melt pool. The regime between 1 bar and ∼50 mbar (the threshold pressure at which the penetration depth no longer increases) could provide a window for successful processing but might require a pre-sinter to maintain the integrity of the powder bed. Lower pressures would definitely require a pre-sinter, for which the additional processing time and increase in process complexity might be justified for porosity-critical applications.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Machine Tools and Manufacture - Volumes 130–131, August 2018, Pages 65-72
نویسندگان
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