Modelling and optimization of laser polishing of additive laser manufacturing surfaces

Abstract

Purpose Direct metal deposition (DMD) with laser is an additive manufacturing process enabling rapid manufacturing of complex metallic and thin parts. However, the final quality of DMD-manufactured surfaces is a real issue that would require a polishing operation. Polishing processes are usually based on abrasive or chemical techniques. These conventional processes are composed by many drawbacks such as accessibility of complex shapes, environmental impacts, high time consumption and cost, health risks for operators, etc. […] This paper aims to solve these problems and improve surface quality by investigating the laser polishing (LP) process. Design/methodology/approach Based on melting material by laser, the LP process enables the smoothing of initial topography. However, the DMD process and the LP processes are based on laser technology. In this context, the laser DMD process is used directly on the same machine for the polishing operation. Currently, few studies focus on LP of additive laser manufacturing surfaces, and it tends to limit the industrial use of additive manufacturing technology. The proposed study describes an experimental analysis of LP surfaces obtained by DMD process. Findings The investigation results in the improvement of a complete final surface quality, according to LP parameters. For mastering LP processes, operating parameters are modelled. Originality/value This experimental study introduces the LP of thin and complex DMD parts, to develop LP applications. The final objective is to create a LP methodology for optimizing the final topography and productivity time according to parts’ characteristics.

Influence of Overlap on Surface Quality in the Laser Polishing of 3D Printed Inconel 718 under the Effect of Air and Argon

“…For the argon trial (1.a), the increasing overlap results in an almost linearly decreased Sa. Moreover, the best results can be achieved for higher overlaps, which generally proves the findings that were presented by Rosa et al [24], Bhaduri et al [21], and Hafiz et al [23]. However, in the case of air, the lowest roughness is achieved for 85% Roughness analysis (Figure 10) reveals that an almost equal mean surface roughness (Sa) is achieved for OL = 50% for both the argon and air atmospheres (2.06 and 1.81 µ m, respectively).…”

“…Rosa et al reported that the overlap parameter has an impact on the surface integrity and surface roughness. Moreover, the authors highlighted that increasing overlap from 60% tends to create micro-cracks in the case of the CW-LP of 3D printed 316L steel parts [ 24 ]. Yung et al showed that the hatching distance can not only have an influence on roughness, but also on the wettability of the surface after LP [ 25 ].…”

Laser polishing of titanium surfaces obtained by additive manufacturing process

“…This strategy enables increase in interaction time between the laser and the surface, without increasing energy density for limit heat transfer for thin structures. The previous works on 316L material have shown that for 4 and 5 passes the surface evolution is limited [23]. For this reason, only 1 and 5 passes are applied to Ti6Al4V surfaces.…”

“…A few studies on laser polishing of titanium are proposed [16][17][18][19][20][21][22], but only one focus partially on laser polishing of LMD titanium surfaces [23]. In this study, laser polished LMD surfaces is investigated, but no multiscale analysis is effectuated.…”

Material Characterization, Thermal Analysis, and Mechanical Performance of a Laser-Polished Ti Alloy Prepared by Selective Laser Melting

“…Rosa et al examined the effect of laser polishing on stainless steel and Ti surfaces via laser metal deposition (LMD), and provided statistical models to determine the settings of operating parameters according to surface roughness specification. The results obtained a final surface roughness of 0.79-0.23 µm for an initial Sa of 21-1.8 µm [12]. Bhaduri et al reported laser polishing results in AM 316L stainless steel with the reduction of surface roughness from 3.8 µm to 0.2 µm [13].…”