A Real-Time Method to Detect the Deformation Behavior during Laser Solid Forming of Thin-Wall Structure

Hua Tan,Yuguang Chen,Wei Hou,Wei Fan,Xin Lin,Zhe Feng

doi:10.3390/met10040508

Abstract

Laser solid forming (LSF) is a promising additive manufacturing technology. In the LSF process, deformation behaviors dictate the accuracy of the produced parts. In this study, by using a laser displacement detector based on laser triangulation principle, an accurate and effective real-time detection method was established to monitor the real-time deformation behavior of the key position during the LSF of a thin-wall structure. The results confirmed that increasing thin-wall length results in increasing final deformation of the edge. The displacement fluctuation range and value in the middle of thin wall are both smaller than that of the positions near the end, while the entire displacement changing direction in the middle is opposite to that of the end positions. When the deposition process is paused, the deformation of the thin wall during the cooling stage will deviate the position of the deposited thin wall, resulting in the dislocation between the subsequent deposited part and that before the pause, which affect the dimensional accuracy of the thin wall structure. This non-contact real-time detection method also confirmed the ability to monitor the initiation of cracking during the LSF process, and a potential to be used for the on-line feedback control of deformation of detected key position of deposited structure.

Highlights

The Laser solid forming (LSF) process is an advanced additive manufacturing technology
By using a laser displacement detector based on laser triangulation principle, an accurate and effective on-line detection method was established to monitor the key position during the LSF of thin-wall structure, so the real-time deformation evolution of the key position on the thin wall deposited were investigated
Figure shows the deformation results at the monitoring points shown in Figure 4a–c was performed to record the deformation at the edges of different lengthduring thinthe LSF

Summary

Introduction

The Laser solid forming (LSF) process is an advanced additive manufacturing technology. Metal powder is required to be transported by gas flow simultaneously to a molten pool created by laser beam on substrate composed of original or previously-deposited material. The movement of the laser beam solidifies the molten pool and forms a deposited layer with full-density, crack-free deposit, and full-strength fusion bond to the substrate under appropriate operating conditions [6]. This process has been used for the direct fabrication of metal parts, surface coating, and repairing damaged components [7–9], and can be used to produce functional-gradient materials [10,11] and composite materials [12,13], both of which cannot be fabricated via conventional means. Many pieces of research focused on the process, microstructure, and properties of LSF technology [14–16]

Methods

Results

Conclusion