Effect of powder particle size distribution and contouring on build quality in electron beam powder bed fusion of a medium-C hot-work tool steel

• An electron beam powder bed fusion (EPBF) printability study of a medium-C hot-work tool steel with focus on part density and surface roughness was performed using three different powder particle size distributions (PSDs) of 45–105 μm (typical for EPBF), 20–60 μm (typical for laser beam powder bed fusion), and a 50–50 wt.% mixture of these two powders. First, acceptable process parameter windows were generated based on as-printed density for each PSD. Full density parts (at least 99.5% dense according to NIST) were produced using the 20–60 μm PSD and the mix PSD. Fifteen different contouring strategies were also tested for potential improvement of the as-printed side surface roughnesses, which ranged from 23.3 to 25.7 μm among the three PSDs. Side surface roughness as low as 13.8 μm was attained by using contouring strategies employing two contouring lines, which were typically observed to be more effective than one-line strategies. Overall, the 20–60 μm PSD was determined to convey a better as-printed build quality over a wider range of parameters without sacrificing process productivity.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

Nyckelord

Electron beam powder bed fusion

Particle size distribution

Surface roughness

Tool steel

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