Project Report: Metal Additive Manufacturing of Stainless Steel 316L

This project report focuses on the challenges and issues associated with metal additive manufacturing (AM) of Stainless Steel 316L. The report begins with an introduction to additive manufacturing and its applications, highlighting the importance of addressing current limitations. The primary issues discussed include surface finish, porosity, and residual stress, which significantly impact the quality and performance of 3D-printed metal parts. The report elaborates on each issue, explaining their causes and consequences, and suggesting potential solutions such as powder bed fusion for surface finish, elimination of gas pockets to reduce porosity, and heat treatment and support structures to manage residual stress. The report concludes by emphasizing the usefulness of AM for complex designs and the ongoing need to refine techniques to overcome existing challenges, referencing relevant literature to support the analysis.

Metal Additive
Manufacturing
Stainless Steel 316L

Introduction:
• Additive Manufacturing is used for creating three
dimensional parts.
• Currently there are several issues in the additive
manufacturing process.
• Issues in the metal AM manufacturing process will be
identified and presented briefly for the Stainless Steel
316L.

Current issues in Additive Manufacturing:
• The main issues currently faced by the additive
manufacturing are the Surface Finish, Porosity and the
Residual Stress [1].
• Due to this issues output products from the additive
manufacturing process are very low quality.
• There are various additive manufacturing process which
can be used for rectifying the above issues of
manufacturing.

Surface Finish Issue:
• Due to this issue of additive manufacturing surface of the
3D printed material remains bumpy and rough.
• Powder Bed Fusion can be used fix this partially.
• Applying a layer of finer particles on the manufactured
product will solve this issue.

Porosity in Additive Manufacturing of 316L:
• The porosity issue is occurrence of small cavities in the
manufactured product.
• Porosity can make the product vulnerable as it can
cracked easily.
• For avoiding this type of issues gas pockets in
manufacturing process should be eliminated.

Residual Stress Issue:
• Residual Stress issue leads to
cracks in the stainless steel
manufacturing.
• Residual Stress is the result of
expansion and contraction
and heating and cooling.
• Residual Stress can be
managed by heat treatment
process and by providing a
support structure.

Conclusion:
• Additive manufacturing is useful for achieving complicated
designs with very much lower effort.
• Metal AM process is not error free and currently
consisting various issues.
• Techniques for avoiding issues in metal AM has been
discussed.

References:
[1] Lewandowski, John J., and Mohsen Seifi. "Metal additive manufacturing:
a review of mechanical properties." Annual Review of Materials
Research 46 (2016): 151-186.
[2] Tapia, G., A. H. Elwany, and H. Sang. "Prediction of porosity in metal-
based additive manufacturing using spatial Gaussian process
models." Additive Manufacturing 12 (2016): 282-290.
[3] Denlinger, Erik R., Jarred C. Heigel, Pan Michaleris, and T. A. Palmer.
"Effect of inter-layer dwell time on distortion and residual stress in additive
manufacturing of titanium and nickel alloys." Journal of Materials
Processing Technology 215 (2015): 123-131.
[4] Turner, Brian N., and Scott A. Gold. "A review of melt extrusion additive
manufacturing processes: II. Materials, dimensional accuracy, and surface
roughness." Rapid Prototyping Journal 21, no. 3 (2015): 250-261.