Effect of Interlayer Cooling Time, Constraint and Tool Path Strategy on Deformation of Large Components Made by Laser Metal Deposition with Wire

Abstract

Laser metal deposition with wire (LMD-w) is a developing additive manufacturing (AM) technology that has a high deposition material rate and efficiency and is suitable for fabrication of large aerospace components. However, control of material properties, geometry, and residual stresses is needed before LMD-w technology can be widely adopted for the construction of critical structural components. In this study, we investigated the effect of interlayer cooling time, clamp constraints, and tool path strategy on part distortion and residual stresses in large-scale laser additive manufactured Ti-6Al-4V components using finite element method (FEM). The simulations were validated with the temperature and the distortion measurements obtained from a real LMD-w process. We found that a shorter interlayer cooling time, full clamping constraints on the build plates, and a bidirectional tool path with 180° rotation minimized part distortion and residual stresses and resulted in symmetric stress distribution.

Wire Arc Additive Manufacturing of Stainless Steels: A Review

“…However, the right-end of the build is lower than anticipated, because residual heat from the previous deposited layers causes the metal to flow more [116]. In general, proper deposition paths can notably reduce residual stresses and deformation, particularly in large scale WAAM fabrication [33,114]. in WAAM [113,114].…”

“…The repeated heating and cooling can cause thermal expansion and shrinkage of the deposited parts, leading to deformation, especially in large thin-walled components [109]. Residual stresses and distortion are closely related to deposition paths in WAAM [113,114]. Lee et al [114] reported that a bidirectional tool path with 180 • rotation decreased the residual stress by around 50% at the bottom corner of the sample, which potentially reduces the cracking susceptibility.…”

“…Residual stresses and distortion are closely related to deposition paths in WAAM [113,114]. Lee et al [114] reported that a bidirectional tool path with 180 • rotation decreased the residual stress by around 50% at the bottom corner of the sample, which potentially reduces the cracking susceptibility. When fabricating martensitic stainless steel samples by the oscillation pass (Figure 9) [115], high distortion occurred in the substrate because of high heat input, as shown in Figure 10.…”

“…In general, proper deposition paths can notably reduce residual stresses and deformation, particularly in large scale WAAM fabrication [33,114]. in WAAM [113,114]. Lee et al [114] reported that a bidirectional tool path with 180° rotation decreased the residual stress by around 50% at the bottom corner of the sample, which potentially reduces the cracking susceptibility.…”

“…In theory, if the martensite transformation is controlled to occur within a certain temperature and time domain, the residual stress can be controlled to a lower level [111]. Proper deposition path planning can significantly reduce residual stresses [114]. Therefore, further efforts should be made to optimize the WAAM deposition path, the thermal history and control the phase transformation during WAAM to reduce the residual stress and distortion through both modelling and experimental studies.…”