Challenges Faced During 3D Metal Printing

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Metal 3D printing minimizes multiple part assembly into one single part. This evolving technology is used for making light 3d metal parts through topology optimization to design high strength components via complex lattice structures.

Metal 3D printing includes:

  • Selective laser sintering (SLM),
  • Electron beam melting (EBM), and
  • Direct metal laser sintering (DMLS)

Metal 3d printing is a challenging process. People related to it, face issues. Some major challenges or issues in 3d metal printing are as follows:

Surface finish–

To apply 3d printed parts in engineering applications like automobile, titanium alloy implant material for dental implants, aerospace, a major amount of post-processing is needed that includes shot peening or sandblasting CNC machining, for desired surface finish.

The powder bed fusion process manufactures parts closer to their ready shape. Thus, fine powder along with low layer thickness can be applied to get a higher surface finish. This increases the cost of the part.

Therefore, an optimum balance between the cost and surface finish is chosen to obtain desired surface finish at a lower cost.

Porosity–

Porosity is like small pores or cavities on a printed part. These pores occurred due to 3d printing process or because of powder utilized in the process. These microscopic holes lessen the density of the 3d part and lead to fatigue and crack.

In the 3d metal printing process, pores are made when the insufficient powder is used and when there is low laser intensity. Pores remain there when the powder particles are bigger than the part’s layer thickness and when insufficient metal flows in the required melt region.

Density-

High porosity in a metal part results in low density. Low density leads to fatigue cracks and failure. For critical applications, 99% and above density is needed.

Concerning density, spherical powder particle is quite helpful in enhancing the part’s density and improving the powder’s flowability. The distribution of wide powder particles leads to the stuffing of a fine particle between the larger parts. It increases the total density of the component; however, it reduces powder’s flowability. Density is controlled through maneuvering AM process parameters.

Cracking-

A crack can arise when the melted metal gets solidified. When powder does not sufficiently melt or re-melts in the layers below the melt pool results in delamination which leads to crack formation between the layers.

You can avoid delamination by heating the substrate. As a result, few cracks can be eradicated via post-processing. The crack formation can also be eradicated via varying the process parameter like scan speed, laser power, and energy density.

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