scholarly journals A Closed-Loop Inspection Architecture for Additive Manufacturing Based on STEP Standard

2019 ◽  
Vol 52 (13) ◽  
pp. 2782-2787
Author(s):  
Cristhian Riaño ◽  
Efrain Rodriguez ◽  
Alberto J. Alvares
Keyword(s):  
Additive Manufacturing ◽  
Closed Loop ◽  
Step Standard

Accelerating Large-Format Metal Additive Manufacturing: How Controls R&D Is Driving Speed, Scale, and Efficiency

2020 ◽  
Author(s):  
Brian T. Gibson ◽  
Paritosh Mhatre ◽  
Michael C. Borish ◽  
Justin L. West ◽  
Emma D. Betters ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Large Scale ◽  
Closed Loop ◽  
Size Control ◽  
Pool Size ◽  
Large Format ◽  
Layer Height ◽  
Melt Pool ◽  
The Impact ◽  
Melt Pool Size

Abstract This article highlights work at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility to develop closed-loop, feedback control for laser-wire based Directed Energy Deposition, a form of metal Big Area Additive Manufacturing (m-BAAM), a process being developed in partnership with GKN Aerospace specifically for the production of Ti-6Al-4V pre-forms for aerospace components. A large-scale structural demonstrator component is presented as a case-study in which not just control, but the entire 3D printing workflow for m-BAAM is discussed in detail, including design principles for large-format metal AM, toolpath generation, parameter development, process control, and system operation, as well as post-print net-shape geometric analysis and finish machining. In terms of control, a multi-sensor approach has been utilized to measure both layer height and melt pool size, and multiple modes of closed-loop control have been developed to manipulate process parameters (laser power, print speed, deposition rate) to control these variables. Layer height control and melt pool size control have yielded excellent local (intralayer) and global (component-level) geometry control, and the impact of melt pool size control in particular on thermal gradients and material properties is the subject of continuing research. Further, these modes of control have allowed the process to advance to higher deposition rates (exceeding 7.5 lb/hr), larger parts (1-meter scale), shorter build times, and higher overall efficiency. The control modes are examined individually, highlighting their development, demonstration, and lessons learned, and it is shown how they operate concurrently to enable the printing of a large-scale, near net shape Ti-6Al-4V component.

scholarly journals Localized electrodeposition micro additive manufacturing of pure copper microstructures

2021 ◽  
Author(s):  
Wanfei Ren ◽  
Jinkai Xu ◽  
Zhongxu Lian ◽  
Xiaoqing Sun ◽  
Zheming Xu ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Electrochemical Deposition ◽  
Closed Loop ◽  
Pure Copper ◽  
Closed Loop Control ◽  
Helical Spring ◽  
Loop Control ◽  
Helical Springs ◽  
Atomic Force ◽  
Microscopic Morphology

Abstract The fabrication of pure copper microstructures with submicron resolution has found a host of applications such as 5G communications and highly sensitive detection. The tiny and complex features of these structures can enhance device performance during high-frequency operation. However, the easy manufacturing of microstructures is still a challenge. In this paper, we present localized electrochemical deposition micro additive manufacturing (LECD-μAM), combining localized electrochemical deposition (LECD) and closed-loop control of atomic force servo technology, which can print helical springs and hollow tubes very effectively. We further demonstrate an overall model based on pulsed microfluidics from a hollow cantilever LECD process and the closed-loop control of an atomic force servo. The printing state of the micro-helical springs could be assessed by simultaneously detecting the Z-axis displacement and the deflection of the atomic force probe (AFP) cantilever. The results showed that it took 361 s to print a helical spring with a wire length of 320.11 μm at a deposition rate of 0.887 μm/s, which could be changed on the fly by simply tuning the extrusion pressure and the applied voltage. Moreover, the in situ nanoindenter was used to measure the compressive mechanical properties of the helical spring. The shear modulus of the helical spring material was about 60.8 GPa, much higher than that of bulk copper (~44.2 GPa). Additionally, the microscopic morphology and chemical composition of the spring were characterized. These results delineated a new way of fabricating terahertz transmitter components and micro-helical antennas with LECD-μAM technology.

Direct Solid Element Slicing in Topology Optimization for Additive Manufacturing

2019 ◽  
Author(s):  
Dylan Bender ◽  
Ahmad Barari
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Closed Loop ◽  
Element Model ◽  
Solid Model ◽  
Manufacturing Constraints ◽  
Manufacturing Process Planning ◽  
Almost All ◽  
The Finite Element Model ◽  
Direct Solid

Abstract The traditional input to almost all commercially available Additive Manufacturing (AM) systems is in STL (Standard Tessellation Language) format, which represents a solid model by its tessellated surfaces. This does not allow transferring the entire information of a solid model to the additive manufacturing preprocessing system. However, in some recent applications such as additive manufacturing preprocessing simulation, closed-loop of topology optimization and additive manufacturing process planning, and AM-based design optimization the full access to the solid model information is necessary. Slicing of the finite element model directly is introduced in this paper. The presented approach enables access to the entire solid model information during the AM preprocessing tasks with a focus on coupling the topology optimization in the design process with the actual manufacturing constraints.

Closed-Loop Control of Silicone Extrusion-Based Additive Manufacturing Based on Machine Vision

2021 ◽  
Author(s):  
Xiaoqing Tian ◽  
Yaling Li ◽  
Dingyifei Ma ◽  
Jiang Han ◽  
Lian Xia
Keyword(s):  
Additive Manufacturing ◽  
Machine Vision ◽  
Manufacturing Process ◽  
Closed Loop ◽  
Ccd Camera ◽  
Control Model ◽  
Loop Control ◽  
Vision Control ◽  
Images Processing ◽  
Printing Speed

Abstract In this paper, the control of strand width uniformity in extrusion-based additive manufacturing process based on machine vision is studied. Firstly, the images of the strand width are collected frame by frame by a CCD camera. Secondly, through a series of processes of images acquisition, images processing including images filtering, images binarization and information extraction, the useful information of strand width is obtained. Then, the theoretical relationship between the strand width and printing speed is obtained through experimental research, and a control model is obtained. Finally, by using the control model and the strand width obtained from images processing, the printing speed is adjusted to an appropriate value, which eventually led to the stabilization of the strand width. The uncontrolled and logarithmic controlled, are studied in this work. The results show that the logarithmic controlled strand width is more stable than the uncontrolled strand width. Therefore, the instability of strand width in material extrusion-based additive manufacturing process can be effectively solved by machine vision control.

The Intelligent Control Method of Additive Manufacturing Flow Based on the Measurement of the Line Width

2014 ◽  
Vol 904 ◽  
pp. 352-356
Author(s):  
Rui Yan Wang ◽  
Ting Chun Shi ◽  
Yi Zhang
Keyword(s):  
Additive Manufacturing ◽  
Line Width ◽  
Intelligent Control ◽  
Closed Loop ◽  
Control Method ◽  
Solid Model ◽  
Current Line ◽  
Loop Control ◽  
Forming Precision ◽  
Displacement Speed

Based on the closed-loop control theory in the paper, an intelligent control method of additive manufacturing based on the measurement of the line width is studied. The setpoint with the current line width which is scanned by the CCD sensor is compared, the relative relationship between the displacement speed of the forming equipments workbench and the rate of flow of the nozzle could be controlled. The Results of the study shows intelligent control of solid model and scaffoldss accuracy, pores shape and porosity, the forming precision is improved greatly makes the cell differentiation, attachment and crawling easy.

Modelling and measuring the thermal behaviour of the molten pool in closed-loop controlled laser-based additive manufacturing

2003 ◽  
Vol 217 (4) ◽  
pp. 441-452 ◽  
Author(s):  
D Hu ◽  
R Kovacevic
Keyword(s):  
Finite Element ◽  
Additive Manufacturing ◽  
Thermal Behaviour ◽  
Molten Pool ◽  
Closed Loop ◽  
Three Dimensional ◽  
Infrared Camera ◽  
Element Model ◽  
Experimental Investigations ◽  
Process Conditions

Laser-based additive manufacturing (LBAM) is a promising manufacturing technology that can be widely applied in solid freeform fabrication (SFF), component recovery and regeneration, and surface modification. The thermal behaviour of the molten pool is one of the critical factors that influences laser deposition indices such as geometrical accuracy, material properties and residual stresses. In this paper, a three-dimensional finite element model is developed using ANSYS to simulate the thermal behaviour of the molten pool in building a single-bead wall via a closed-loop controlled LBAM process in which the laser power is controlled to keep the width of the molten pool constant. The temperature distribution, the geometrical feature of the molten pool and the cooling rate under different process conditions are investigated. To verify the simulation results, the thermal behaviour of the molten pool is measured by a coaxially installed infrared camera in experimental investigations of a closed-loop controlled LBAM process. Results from finite element thermal analysis provide guidance for the process parameter selection in LBAM, and develop a base for further residual stress analysis.

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