Development of a Magnetic Levitation System for Additive Manufacturing Processes

Magnetic levitation and Additive Manufacturing (AM) are both highly innovative fields that have changed the trajectory of development within a wide variety of applications. Magnetic levitation techniques offer noncontact levitation forces that highlight high compatibility with metal AM operations like Laser Directed Energy Deposition via Powder Feeding (LDED-PF) techniques. The research presented in this report aims to highlight the novel implementation of a magnetic levitation system compatible with LDED-PF operations. The suspension of a conductive paramagnetic material geometry through repulsive magnetic levitation techniques will serve as the substrate to build a part through LDED-PF operations. The research contributions are as follows: First, this research develops a novel magnetic levitation system capable of supporting AM operations. The compatibility of the levitation system has been tested through simulations and experiments. Second, the levitation system can support time-varying loads over time without losing stability during AM operations. Finally, a novel parameter to determine the compatibility of different paramagnetic materials with magnetic levitation applications was developed and verified through this research. Two magnetic levitation systems were developed. The first system was composed of a laminated core. This entailed the use of several hundred sheets assembled together to form the core within which the coils were embedded. This resulted in a reduction in eddy current losses within the core, however, the sheets sizes were predefined which resulted in the loss of flexibility for optimization. The second system was composed of a solid core system. This system was subjected to higher eddy current losses, however, offered significantly higher flexibility for optimization. The prototypes were optimized, manufactured, assembled, and tested. Both prototypes successfully highlighted the ability to levitate aluminum discs. Following the successful development of the levitation system prototypes, the next step was the development of a feedback controller to facilitate stable suspension at the desired setpoint. Through the incorporation of a simple Proportional Integral and Derivative (PID) controller using a laser sensor, the rise time was improved. However, a significantly high settling time was still encountered. To overcome this, a PID controller with a compensator component modeling the anticipated initial value of the voltage input was incorporated into the feedback PID controller. Through the implementation of the PID controller with the compensator component, the overshoot was eliminated and the settling time was reduced by 3.9 s. Subsequently, the performance of the levitation system was tested without a feedback controller within the LDED-PF machine experimentally. Copper alloys were deposited on an aluminum alloy build surface that was levitated. Under a high powder feed rate and high laser power, the levitation system was successfully able to support powder deposition activities. The build surface for powder deposition was also maximized through the incorporation of the levitation system within the AM machine. Finally, this research also develops a parameter set that utilizes the material properties of different paramagnetic materials to determine their compatibility with magnetic levitation techniques. Conventionally, there is a strong reliance on the use of experimental implementation to determine whether a material is compatible with magnetic levitation techniques. However, by comparing the ratio of electrical conductivity to the density of the material, the compatibility of the material with magnetic levitation techniques can be determined without any experimental implementation

Development and Analysis of a Novel Magnetic Levitation System with a Feedback Controller for Additive Manufacturing Applications

The primary goal of this study is to create a magnetic levitation system for additive manufacturing (AM) applications. The emphasis of this research is placed on Laser Directed Energy Deposition via Powder Feeding (LDED-PF). The primary benefit of using a magnetic levitation system for AM applications is that the levitated geometry is expected to be a portion of the final part manufactured, thus eliminating the need for a substrate and reducing the post-processing operation requirement. Two novel levitation systems were designed, optimized, and manufactured. The design, optimization, and analysis were first conducted in the simulation environment using ANSYS Maxwell and then tested with experiments. The newly developed systems depicted a much-improved performance compared to the first prototype developed in a previous article written by the authors. The newly developed systems had an increase in levitation height, the surface area for powder deposition activities, the time available for AM operations, and the ability to support additional mass within the limits of allowable inputs. The compatibility of the levitation system with AM applications was also verified by testing the impact of powder deposition and the ability of the levitated disc to support added mass as a function of time with minimal loss in performance. This article also highlights the development of a novel feedback PID controller for the levitation system. To improve the overall performance of the controller, a feedforward controller was added in conjunction with the PID controller. Finally, the levitation system was shown to highlight control over levitation height and maintain constant levitation height with the addition of an added mass using the feedback controller

Development and Analysis of a Novel Magnetic Levitation System with a Feedback Controller for Additive Manufacturing Applications

The primary goal of this study is to create a magnetic levitation system for additive manufacturing (AM) applications. The emphasis of this research is placed on Laser Directed Energy Deposition via Powder Feeding (LDED-PF). The primary benefit of using a magnetic levitation system for AM applications is that the levitated geometry is expected to be a portion of the final part manufactured, thus eliminating the need for a substrate and reducing the post-processing operation requirement. Two novel levitation systems were designed, optimized, and manufactured. The design, optimization, and analysis were first conducted in the simulation environment using ANSYS Maxwell and then tested with experiments. The newly developed systems depicted a much-improved performance compared to the first prototype developed in a previous article written by the authors. The newly developed systems had an increase in levitation height, the surface area for powder deposition activities, the time available for AM operations, and the ability to support additional mass within the limits of allowable inputs. The compatibility of the levitation system with AM applications was also verified by testing the impact of powder deposition and the ability of the levitated disc to support added mass as a function of time with minimal loss in performance. This article also highlights the development of a novel feedback PID controller for the levitation system. To improve the overall performance of the controller, a feedforward controller was added in conjunction with the PID controller. Finally, the levitation system was shown to highlight control over levitation height and maintain constant levitation height with the addition of an added mass using the feedback controller

Development of an Electromagnetic Micromanipulator Levitation System for Metal Additive Manufacturing Applications

Magnetism and magnetic levitation has found significant interest within the field of micromanipulation of objects. Additive manufacturing (AM), which is the computer-controlled process for creating 3D objects through the deposition of materials, has also been relevant within the academic environment. Despite the research conducted individually within the two fields, there has been minimal overlapping research. The non-contact nature of magnetic micromanipulator levitation systems makes it a prime candidate within AM environments. The feasibility of integrating magnetic micromanipulator levitation system, which includes two concentric coils embedded within a high permeability material and carrying currents in opposite directions, for additive manufacturing applications is presented in this article. The working principle, the optimization and relevant design decisions pertaining to the micromanipulator levitation system are discussed. The optimized dimensions of the system allow for 920 turns in the inner coil and 800 turns in the outer coil resulting in a Ninnercoil:Noutercoil ratio of 1.15. Use of principles of free levitation, which is production of levitation and restoration forces with the coils, to levitate non-magnetic conductive materials with compatibility and applications within the AM environment are discussed. The Magnetomotive Force (MMF) ratio of the coils are adjusted by incorporation of an resistor in parallel to the outer coil to facilitate sufficient levitation forces in the axial axis while producing satisfactory restoration forces in the lateral axes resulting in the levitation of an aluminum disc with a levitation height of 4.5 mm. An additional payload of up to 15.2 g (59% of mass of levitated disc) was added to a levitated aluminum disk of 26 g showing the system capability coping with payload variations, which is crucial in AM process to gradually deploy masses. The final envisioned system is expected to have positional stability within the tolerance range of a few μm. The system performance is verified through the use of simulations (ANSYS Maxwell) and experimental analyses. A novel method of using the ratio of conductivity (σ) of the material to density (ρ) of the material to determine the compatibility of the levitation ability of non-magnetic materials with magnetic levitation application is also formulated. The key advantage of this method is that it does not rely on experimental analyses to determine the levitation ability of materials

Development of an Electromagnetic Micromanipulator Levitation System for Metal Additive Manufacturing Applications

Magnetism and magnetic levitation has found significant interest within the field of micromanipulation of objects. Additive manufacturing (AM), which is the computer-controlled process for creating 3D objects through the deposition of materials, has also been relevant within the academic environment. Despite the research conducted individually within the two fields, there has been minimal overlapping research. The non-contact nature of magnetic micromanipulator levitation systems makes it a prime candidate within AM environments. The feasibility of integrating magnetic micromanipulator levitation system, which includes two concentric coils embedded within a high permeability material and carrying currents in opposite directions, for additive manufacturing applications is presented in this article. The working principle, the optimization and relevant design decisions pertaining to the micromanipulator levitation system are discussed. The optimized dimensions of the system allow for 920 turns in the inner coil and 800 turns in the outer coil resulting in a Ninnercoil:Noutercoil ratio of 1.15. Use of principles of free levitation, which is production of levitation and restoration forces with the coils, to levitate non-magnetic conductive materials with compatibility and applications within the AM environment are discussed. The Magnetomotive Force (MMF) ratio of the coils are adjusted by incorporation of an resistor in parallel to the outer coil to facilitate sufficient levitation forces in the axial axis while producing satisfactory restoration forces in the lateral axes resulting in the levitation of an aluminum disc with a levitation height of 4.5 mm. An additional payload of up to 15.2 g (59% of mass of levitated disc) was added to a levitated aluminum disk of 26 g showing the system capability coping with payload variations, which is crucial in AM process to gradually deploy masses. The final envisioned system is expected to have positional stability within the tolerance range of a few μm. The system performance is verified through the use of simulations (ANSYS Maxwell) and experimental analyses. A novel method of using the ratio of conductivity (σ) of the material to density (ρ) of the material to determine the compatibility of the levitation ability of non-magnetic materials with magnetic levitation application is also formulated. The key advantage of this method is that it does not rely on experimental analyses to determine the levitation ability of materials

Experimental Implementation of a Magnetic Levitation System for Laser-Directed Energy Deposition via Powder Feeding Additive Manufacturing Applications

Magnetic levitation and additive manufacturing (AM) are two fields of significant interest in academic research. The use of non-contact forces for magnetic levitation techniques provides opportunities for adoption within the AM environment. The key goal of this article is to experimentally validate the implementation of a magnetic levitation system for Laser-Directed Energy Deposition via Powder Feeding (LDED-PF) Additive Manufacturing applications. Through simulations (conducted in ANSYS Maxwell) and experimental implementation, the levitation system’s stability is tested under a variety of different conditions. The experimental implementation highlights the feasibility of a magnetic levitation system for LDED-PF applications. The levitation system developed is capable of the suspension of non-magnetic materials. The system is also able to maintain stable levitation for extended periods of time. The incorporation of the levitation system into the AM environment may result in an increased maneuverability of non-clamped structures for AM deposition operations