Feedback Control of Melt Pool Area in Selective Laser Melting Additive Manufacturing Process

Abstract

Selective laser melting (SLM), a metal powder fusion additive manufacturing process, has the potential to manufacture complex components for aerospace and biomedical implants. Large-scale adaptation of these technologies is hampered due to the presence of defects such as porosity and part distortion. Nonuniform melt pool size is a major cause of these defects. The melt pool size changes due to heat from the previous powder bed tracks. In this work, the effect of heat sourced from neighbouring tracks was modelled and feedback control was designed. The objective of control is to regulate the melt pool cross-sectional area rejecting the effect of heat from neighbouring tracks within a layer of the powder bed. The SLM process’s thermal model was developed using the energy balance of lumped melt pool volume. The disturbing heat from neighbouring tracks was modelled as the initial temperature of the melt pool. Combining the thermal model with disturbance model resulted in a nonlinear model describing melt pool evolution. The PID, a classical feedback control approach, was used to minimize the effect of intertrack disturbance on the melt pool area. The controller was tuned for the desired melt pool area in a known environment. Simulation results revealed that the proposed controller regulated the desired melt pool area during the scan of multiple tracks of a powder layer within 16 milliseconds and within a length of 0.04 mm reducing laser power by 10% approximately in five tracks. This reduced the chance of pore formation. Hence, it enhances the quality of components manufactured using the SLM process, reducing defects.

Electrical Aircraft Ship Integrated Secure and Traverse System Design and Key Characteristics Analysis

“…The dynamic model of the transmission system was established, and the simulation results show that the dynamic model can better describe the dynamic characteristics of the system [46,47]. This result provides a theoretical basis for subsequent production and processing.…”

A Review on Vibration Characteristics of Additively Manufactured Metal Alloys

“…[74,75] The printing orientation can influence the vibration characteristics of a material in AM. [22,23,76] For instance, Lesage et al analyzed the vibrational response of AlSi10Mg samples produced using conventional and AM methods. [21] The AM samples were printed in horizontal (flat), vertical (upright), and rotated orientations, with the build angle ranging from 0°to 90°.…”

Integrated Thermal and Metallurgical Simulation Framework for Selective Laser Melting Multi-Component and Multi-Phase Alloys

“…This parameter exhibits associations with various factors, including powder density, material vapor pressure, and the enthalpy of material phase changes. P is laser power, W; and V ∆t,h pool represents the volume of the metal molten pool under the action of a high-energy laser, which can be calculated by laser scanning speed, time interval, hatch spacing, and layer thickness, m 3 .…”

“…In characterizing heat dissipation during the SLM process, it is postulated that the primary modes of heat dissipation for the top layer are thermal convection and thermal radiation, and these play a significant role in dissipating heat from the components during the printing process. Conversely, the heat exchange between the side of the component and the adjacent powder layer is approximated through thermal convection, and the heat dissipation can be expressed as shown in Equation (3). By combining Equation (2) and Equation (3), when the equivalent micro-zone heat source is applied to the component's surface area, the total heat comprises the sum of the heat input and heat dissipation.…”

“…SLM is an advanced manufacturing technology that has gained significant attention due to its ability to produce complex metal components directly from metal powders, with high precision. This technology exhibits several distinctive features, including a high flexibility in regards to design freedom, minimal tooling requirements, efficient material utilization, and excellent batch consistency, affording it extensive applications in the medical and aerospace industries [1][2][3]. While the promise of this technology has garnered increasing interest from researchers, who are actively broadening its applications, practical challenges persist.…”