Browsing by Author "Wang, Chong"
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Item Open Access Automated interlayer wall height compensation for wire based directed energy deposition additive manufacturing(MDPI, 2023-10-16) Qin, Jian; Vives, Javier; Raja, Parthiban; Lasisi, Shakirudeen; Wang, Chong; Charrett, Thomas O. H.; Ding, Jialuo; Williams, Stewart; Hallam, Jonathan Mark; Tatam, Ralph P.Part quality monitoring and control in wire-based directed energy deposition additive manufacturing (w-DEDAM) processes has been garnering continuous interest from both the academic and industrial sectors. However, maintaining a consistent layer height and ensuring that the wall height aligns closely with the design, as depicted in computer-aided design (CAD) models, pose significant challenges. These challenges arise due to the uncertainties associated with the manufacturing process and the working environment, particularly with extended processing times. To achieve these goals in an industrial scenario, the deposition geometry must be measured with precision and efficiency throughout the part-building process. Moreover, it is essential to comprehend the changes in the interlayer deposition height based on various process parameters. This paper first examines the behaviour of interlayer deposition height when process parameters change within different wall regions, with a particular focus on the transition areas. In addition, this paper explores the potential of geometry monitoring information in implementing interlayer wall height compensation during w-DEDAM part-building. The in-process layer height was monitored using a coherent range-resolved interferometry (RRI) sensor, and the accuracy and efficiency of this measurement were carefully studied. Leveraging this information and understanding of deposition geometry, the control points of the process parameters were identified. Subsequently, appropriate and varied process parameters were applied to each wall region to gradually compensate for wall height. The wall height discrepancies were generally compensated for in two to three layers.Item Open Access Bead shape control in wire based plasma arc and laser hybrid additive manufacture of Ti-6Al-4V(Elsevier, 2021-07-16) Wang, Chong; Suder, Wojciech; Ding, Jialuo; Williams, Stewart W.Wire based plasma transferred arc (PTA)-laser hybrid additive manufacture has the potential to build large-scale metal components with high deposition rate and near-net shape. In this process, a single bead is the fundamental building block of each deposited component, and thus the bead shape control is essential for the deposition of different geometries. However, how to control the bead shape by manipulating various process parameters is still not understood. In this study, the effect of different process parameters, including laser power, energy distribution between the PTA and laser, wire feed speed, travel speed, and laser beam size on the deposition process and bead shape was investigated systematically. The results show that the optimum operating regime for the hybrid process is with the wire being fully melted by the PTA and the melt pool being controlled by the laser, which gives a good bead shape as well as a stable deposition process. The bead shape is significantly affected by the laser power and travel speed due to the large variation in energy input. The effect of wire feed speed is more complex with the bead width initially increasing to a maximum and then decreasing as the wire feed speed increases. The laser beam size has a minor effect on the bead shape, but a small beam size will result in an irregular bead appearance due to the unstable process caused by the high power density. In addition, a procedure for controlling the bead shape in the hybrid process was proposed, which provided a reference for selection of different process parameters to achieve required bead shapes. The feasibility of this proposed procedure was demonstrated by the two deposited multi-layer single-pass walls.Item Open Access Data supporting "A novel cold wire gas metal arc (CW-GMA) process for high productivity additive manufacturing"(Cranfield University, 2023-06-30 11:53) Wang, Chong; Wang, Jun; Bento, João; Ding, Jialuo; Rodrigues Pardal, Goncalo; Chen, Guangyu; Qin, Jian; Suder, Wojciech; Williams, StewartThis is a supplementary figure, showing the experimental setup for building the large-scale component with the CW-GMA process: (a) experiment setup, and (b) monitors for thermal camera and process camera.Item Open Access Data supporting: 'Multi-Energy Source (MES) Configuration for Bead Shape Control in Wire-based Directed Energy Deposition (w-DED)'(Cranfield University, 2022-08-31 15:42) Chen, Guangyu; Suder, Wojciech; Williams, Stewart; Ding, Jialuo; Wang, ChongVideo shows the the dynamic changing of the melt pool and highspeed scanning motion of the laser beam.Item Open Access Data supporting: 'Wire based plasma arc and laser hybrid additive manufacture of Ti-6Al-4V'(Cranfield University, 2022-11-23 16:47) Wang, Chong; Suder, Wojciech; Ding, Jialuo; Williams, StewartThese are two supplementary videos for Fig 5, showing different configurations for wire based PTA-laser hybrid additive manufacturing process.Item Open Access Data: Automated interlayer wall height compensation for wire based directed energy deposition additive manufacturing(Cranfield University, 2024-05-08 16:28) Qin, Jian; Vives, Javier; Rajan, Parthiban; Lasisi, Shakirudeen; Wang, Chong; Charrett, Tom; Ding, Jialuo; Williams, Stewart; Hallam, Jonathan; Tatam, RalphExperimental dataset to support the publication. The data includes all the test and measurement records for the experiment.Item Open Access Data: Process control methods in cold wire gas metal arc additive manufacturing(Cranfield University, 2023-08-01 10:54) Bento, João; Wang, Chong; Ding, Jialuo; Williams, StewartData supporting the study published with the name: Process control methods in cold wire gas metal arc additive manufacturingItem Open Access Data: Thermo-Capillary-Gravity Bidirectional Modelling for Evaluation and Design of Wire-Based Directed Energy Deposition Additive Manufacturing(Cranfield University, 2023-10-31 11:08) Mosalman Haghighi, Alireza; Ding, Jialuo; Sun, Yongle; Wang, Chong; Williams, StewartIn this study, a thermo-capillary-gravity bidirectional analytical model is developed based on the fundamental governing physics, enabling fast predictions of both w-DED bead geometries and process parameters. A novel method is also proposed to determine the power transfer efficiency and wire melting efficiency defined in the model. In the forward modelling, deposit bead geometries, such as layer height and width, can be predicted for given process parameters and material properties. In the reverse modelling, the outputs of the model are process parameters, including heat source power and travel speed, to achieve the deposit bead geometries as required for a given application. This bidirectional modelling approach is applicable to different w-DED processes, and it has been validated for the deposition of steel walls using plasma transferred arc and cold wire gas metal arc processes. The developed bidirectional analytical model could be used as an efficient and reliable tool for w-DED process evaluation and design.Item Open Access The effect of wire size on high deposition rate wire and plasma arc additive manufacture of Ti-6Al-4V(Elsevier, 2020-07-25) Wang, Chong; Suder, Wojciech; Ding, Jialuo; Williams, StewartWire + arc additive manufacture (WAAM) is suitable for building large-scale components with high deposition rate. However, in order to further increase the deposition rate of Ti-6Al-4V to improve productivity and reduce manufacture costs without significantly compromising the quality, some fundamental process characteristics need to be investigated. In this paper, the effect of wire size on the limitation of deposition rate and bead shape in plasma arc additive manufacture was studied along with the process tolerance and melting characteristics, such as the effect of current and nozzle size on keyhole behaviour and the effect of wire feeding position on deposition process. The results show that with the same heat input the deposition rate increases linearly with the wire size due to the increasing melting efficiency. The bead geometry obtained with a thinner wire has a higher aspect ratio, which can be attributed to the difference in the distribution of the energy between wire and workpiece. The likelihood of keyhole increases with increasing current and decreasing nozzle size, and it can be mitigated by using thicker wires. The wire feeding position plays a significant role in determining the metal transfer mode, which has a great impact on the bead shape and process stability. Also, as the deposition rate changes thin wire is more sensitive to wire feeding position than thick wire in terms of metal transfer behaviourItem Open Access Efficient reduced-order thermal modelling of scanning laser melting for additive manufacturing(Elsevier, 2023-10-02) Chen, Guangyu; Ding, Jialuo; Sun, Yongle; Chen, Xin; Wang, Chong; Rodrigues Pardal, Goncalo; Williams, StewartAdditive manufacturing (AM) with a scanning laser (SL) to independently control melt pool shape has the potential to achieve part building with high geometric accuracy and complexity. An innovative dynamic convection boundary (DCB) method is proposed to develop a reduced-order finite element (FE) model to accelerate the thermal analysis of a SL process for AM. The DCB method approximates the thermal conduction of the adjacent material around the bead region by using a convection boundary condition that can be dynamically adjusted during the numerical solution. Thereby, a smaller problem domain and fewer elements are involved in the reduced-order FE modelling. A non-oscillating equivalent bar-shaped heat source was also introduced as a simplified substitution for a high oscillation frequency SL heat source. The DCB-based reduced-order thermal model achieved over 99% accuracy compared to the full-scale model but reduced the element amount by 73% and the computational time by 58%. The use of the bar-shaped equivalent heat source can further enhance computational efficiency without compromising the prediction accuracy of a high oscillation frequency SL process. The DCB-based reduced-order thermal modelling method and equivalent heat source could be adopted to boost extensive parametric analysis and optimisation for novel AM processes. Study on large structures AM could also be facilitated by simplifying the computation at critical regions. This study can also enable efficient thermal analyses of different manufacturing processes, such as welding, cladding, and marking.Item Open Access Efficient reduced-order thermal modelling of scanning laser melting for additive manufacturing.(Cranfield University, 2023-09-25 16:20) Chen, Guangyu; Ding, Jialuo; Sun, Yongle; Chen, Xin; Wang, Chong; Rodrigues Pardal, Goncalo; Williams, StewartThermal videos show the dynamic changing of the scanning laser melt pools with different oscillation frequenciesItem Open Access High deposition rate wire based additive manufacture of Ti-6Al-4V.(Cranfield University, 2020-12) Wang, Chong; Suder, Wojciech; Ding, JialuoWire + arc additive manufacture (WAAM) is characterised by high deposition rate, short lead-time and relatively low cost, making it suitable for building large-scale metal components. In practical production, high deposition rates are required to reduce the lead-time and overall costs of the components. However, there is a trade-off between the productivity and quality of the deposited components. This is because the fundamental building block of each part, the shape of each individually deposited bead, is dictated by the melt pool dynamics, which is more challenging to control at high heat inputs with any single axisymmetric heat source. Therefore, this thesis undertakes a study of a novel wire based additive manufacture (AM) process, which combines a plasma transferred arc (PTA) and a laser heat sources, aiming to achieve high deposition rates and near-net shape. First, the limitations of a single PTA deposition process, in terms of the deposition rate and process tolerance were obtained. It was found that the deposition rate can be improved by changing the energy distribution between the wire and the workpiece. This can be done by increasing the wire diameter or changing the position of the wire with respect to the arc column. To enable a further increase of energy input and deposition rate but without increasing the likelihood of keyhole defects formation, a novel configuration of the PTA process with the vertical wire and inclined torch was examined. Although this process is not omnidirectional, it could reduce the likelihood of keyhole formation. The interaction between the PTA and laser was studied using a finite element (FE) model. This model could predict thermal conditions, such as melt pool geometry, for different process parameters. A wire based PTA-laser hybrid AM process was developed, and the possibility of independent control of deposition rate and bead shape was studied. It has been demonstrated that near-net-shape parts at high deposition rates could be achieved with the PTA-laser hybrid AM. In addition, with the PTA to melt the wire and the laser to control the melt pool size, the deposition rate and bead shape could be controlled independently in the hybrid process. This was then extended to a multi-energy source (MES) approach with two lasers and a PTA. Despite the increased complexity of such a process, it is easier to control the bead dimensions and thermal cycle independently.Item Open Access Hybrid PTA-laser melting process(Cranfield University, 2023-01-19 17:22) Wang, Chong; Suder, Wojciech; Ding, Jialuo; Williams, StewartThis is a supplementary video showing the hybrid PTA-laser melting process.Item Open Access Investigation of 300M ultra-high-strength steel deposited by wire-based gas metal arc additive manufacturing(Springer, 2023-11-01) Wang, Jun; Diao, Chenglei; Taylor, Mark; Wang, Chong; Pickering, Ed; Ding, Jialuo; Pimentel, Misael; Williams, Stewart300 M ultra-high-strength steel (UHSS) is widely used to produce landing gear components for aircraft. The conventional manufacturing route for these components involves extensive machining and significant material wastage. Here, the application of wire-based gas metal arc additive manufacturing to produce 300 M UHSS parts was investigated. In particular, the influence of torch shielding atmosphere on the process stability and material performance of 300 M UHSS was investigated. The shielding gases used for comparison are pure Ar, Ar with 2.5% CO2, Ar with 8% CO2, Ar with 20% CO2, and Ar with 2% CO2 and 38% He. It was found that the arc length decreased, the transfer mode changed from spray to droplet mode, and spattering became more severe as the CO2 proportion increased. Additionally, replacing Ar with He led to a broader arc core, and a slightly shorter arc length and maintained a spray transfer, which decreased spatter. The wall surface roughness followed the trend in spatter, becoming worse with the increasing CO2 proportion, and better with He addition. Adding CO2 and He in pure Ar significantly increased the bead and wall width. The microstructure and mechanical properties exhibited a strong location dependence in the as-built state, with fresh martensite and higher strength in the top region, and tempered martensite and better ductility in the reheated bulk. Generally, torch shielding gas composition appeared to have no significant effect on the microstructure evolution. This study provides a reference for the subsequent application of gas metal arc additive manufacturing to aircraft landing gear mass production to achieve a high deposition rate and process stability simultaneously.Item Open Access Multi-energy source (MES) configuration for bead shape control in wire-based directed energy deposition (w-DED)(Elsevier, 2022-03-09) Chen, Guangyu; Williams, Stewart; Ding, Jialuo; Wang, Chong; Suder, WojciechA multi-energy source (MES) method featuring a high-power scanning laser (SL) was used to achieve independent control of layer width and height in a wire-based directed energy deposition (w-DED) process. In the MES system, a plasma transferred arc (PTA) was employed to create an initial melt pool and melt the wire, and a SL was used to reshape the melt pool and precisely control the bead width. The distance between the SL and the PTA and different laser scanning strategies were investigated. Images of the melt pool with varying scanning widths were captured. A bead shape control strategy was demonstrated by using the wire feed speed to control layer height and the laser scanning width to control the layer width independent of each other. The advancing speed was adjusted in proportion to the scanning width to keep the same specific process energy of the SL. The experimental results demonstrated that the MES approach provides independent control of layer width and height. Some single-pass walls were built using the MES to show that MES can be used for w-DED additive manufacturing.Item Open Access A novel cold wire gas metal arc (CW-GMA) process for high productivity additive manufacturing(Elsevier, 2023-07-01) Wang, Chong; Wang, Jun; Bento, João; Ding, Jialuo; Rodrigues Pardal, Goncalo; Chen, Guangyu; Qin, Jian; Suder, Wojciech; Williams, StewartWire-arc directed energy deposition (DED) is suitable for depositing large-scale metallic components at high deposition rates. In order to further increase productivity and efficiency by reducing overall manufacturing time, higher deposition rates are desired. However, the conventional gas metal arc (GMA) based wire-arc DED, characterised by high energy input, normally results in high remelting and reheating at relatively high deposition rates, reducing the process efficiency and deteriorating the mechanical performance. In this study, a novel wire-arc DED process with the combination of a GMA and an external cold wire, namely cold wire-gas metal arc (CW-GMA), was proposed for achieving high deposition rate and low material remelting. The maximum deposition rates at different levels of energy input were investigated, with the highest deposition rate of 14 kg/h being achieved. An industrial-scale component weighing 280 kg was built with this process at a high deposition rate of around 10 kg/h, which demonstrated the capability of the process for high productivity application. It was also found that, due to the addition of the cold wire, the remelting was reduced significantly. The working envelope and geometric process model for the CW-GMA process was developed, which can be used to avoid defects in parameter selection and predict the geometry of single-pass wall structures. Moreover, the addition of the cold wire in the CW-GMA process reduced the specific energy density, leading to a reduction in both grain size and anisotropy, which improved the mechanical properties with increased strength and reduced anisotropy.Item Open Access Parametric study of melt pool geometry in hybrid plasma arc-laser melting process for additive manufacturing application(Springer, 2023-01-20) Wang, Chong; Suder, Wojciech; Ding, Jialuo; Williams, StewartWire-based hybrid arc-laser additive manufacturing is suitable for producing large metallic parts (metres in scale) with high deposition rates and near-net-shape. In this process, the surface quality and dimensional accuracy of the deposited parts are determined by the melt pool geometry. However, how to control the melt pool in the hybrid process is complex due to the multiple parameters that can be used. In this study, control of melt pool geometry by investigating different process parameters, including laser power, travel direction, arc-laser separation distance, laser beam size, and arc current in the hybrid plasma transferred arc (PTA)-laser process, was studied systematically. It was found that a larger melt pool was achieved with the PTA-leading configuration compared to that with the laser-leading configuration due to a higher laser absorption occurred with the former configuration. The melt pool was enlarged by either increasing the laser power or arc current due to the increased energy input. However, if the laser power density is high enough to determine the melt pool depth, the increasing arc current has very little effect on melt pool depth but only increases the melt pool width. In addition, the melt pool became shallower and wider when using a larger laser beam. The arc-laser separation distance had a minor effect on the melt pool geometry due to the fixed energy input used in the studied cases. The results of this study provide a reference for melt pool control in wire-based hybrid arc-laser additive manufacturing.Item Open Access Process control methods in cold wire gas metal arc additive manufacturing(MDPI, 2023-07-26) Bento, João; Wang, Chong; Ding, Jialuo; Williams, StewartCold wire gas metal arc (CWGMA) additive manufacturing (AM) is more productive and beneficial than the common electric arc processes currently used in wire arc additive manufacturing (WAAM). Adding a non-energised wire to the gas metal arc (GMA) system makes it possible to overcome a process limitation and decouple the energy input from the material feed rate. Two novel process control methods were proposed, namely, arc power and travel speed control, which can keep the required geometry accuracy in WAAM through a broad range of thermal conditions. The reinforcement area of the bead is kept constant with accurate control over the height and width while still reducing the energy input to the substrate; decreasing penetration depth, remelting, and the heat-affected zone (HAZ); and reaching a dilution lower than 10%. This work also presents improved productivity compared to all the other single-arc energy-based processes with a demonstrator part built using 9.57 kg h−1 with CWGMA AM.Item Open Access A simplified modelling approach for thermal behaviour analysis in hybrid plasma arc-laser additive manufacturing(Elsevier, 2022-06-25) Wang, Chong; Sun, Yongle; Chen, Guangyu; Chen, Xin; Ding, Jialuo; Suder, Wojciech; Diao, Chenglei; Williams, StewartHybrid plasma transferred arc (PTA)-laser additive manufacturing (AM) has the potential to build large-scale metal components with high deposition rate and near-net shape. However, the process is complex with many parameters adjustable for process control, which determine the thermal behaviour and thus the final structure and properties of the deposited components. In this study, a three-dimensional steady-state finite element model with two independent circular surface heat sources was developed, validated, and used to analyse the thermal behaviour in hybrid PTA-laser AM of Ti-6Al-4V. Artificial conductivity in three orthogonal directions was applied in the melt pool to compensate for the melt pool convection effect. The predicted melt pool geometry, heat-affected zone and thermal cycles had good agreement with the corresponding experimental data. This model has advantages over the widely used volumetric heat source model, since it is more representative of the energy sources used, giving accurate thermal prediction for a wide range of process parameters. As the heat source parameters in this model are directly linked to the actual arc/laser size, it enables to capture heat source size effect on the hybrid process. In addition, it is easier to calibrate compared to the model with volumetric heat sources due to the fewer empirical parameters involved. It was found that in the investigated ranges of all the parameters, the melt pool geometry is more sensitive to laser power and travel speed compared to arc-laser separation distance and laser beam size. The full-field distributions of the cooling rate and temperature gradient in the hybrid process were obtained and the roles that different process parameters played on them were also studied, which provided useful thermal information for metallurgical analysis.Item Open Access Thermal fluid dynamics of the effect of filler wire on deposition rate and bead formation intending plasma arc-based DED(Cranfield University, 2023-10-23 09:07) Chen, Xin; Wang, Chong; Ding, Jialuo; Qu, Rongdong; Wang, Yipeng; Rodrigues Pardal, Goncalo; Williams, StewartVideos of the simulations generated by this research.