A. Sreenathbabu, K.P. Karunakaran and C. Amarnath
This paper discusses the optimization of the process parameters for the hybrid‐layered manufacturing (HLM) process during its weld layer deposition with subsequent surface…
Abstract
Purpose
This paper discusses the optimization of the process parameters for the hybrid‐layered manufacturing (HLM) process during its weld layer deposition with subsequent surface machining in attaining the desired accuracy and contour profile of the deposited weld layer thickness.
Design/methodology/approach
The HLM process integrates the synergic metal inert gas (MIG) – metal active gas (MAG) welding process for depositing the metal layer of a desired slice thickness and perform the computer numerical control (CNC) machining process on the deposited layer to enhance both the surface quality and dimensional accuracy of the deposited layer. For the HLM process the weld bead geometry plays a vital role in determination of the layer thickness, surface quality, build time, heat input into the deposited layer and the hardness attained by the prototype. A feasible weld bead width and heights are to be formulated for the exterior contour weld path deposition and for the interior weld cladding. Thus, Taguchi methodology was employed with minimum number of trails as compared with classical statistical experiments. This study systematically reveals the complex cause‐effect relationships between design parameters and performance.
Findings
Statistical design of experiments using orthogonal arrays and signal‐to‐noise (S/N) ratios are performed to constitute the core of the robust design procedure. Experimental confirmations of the performance characteristic using the derived optimal levels of process parameters are provided to confirm the effectiveness of this approach.
Research limitations/implications
The welding parameters such as current, voltage, arc length, wire feed rates, wire stick‐out distance, shielding gas, filler wire diameter, weld speed, etc. will influence on the deposited weld bead geometry. Further investigations are to be carried out during adaptive layer deposition on the induced thermal stresses and its influence on the hardness of the deposited weld layer.
Originality/value
This paper describes a low cost direct rapid tooling process, HLM. This unique methodology would reduce the cost and time to make molds and dies that are used in batch production.
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The objective of this study is to investigate the effect of various parameters on rapid prototyping parts for processes of sintering metallic powder by using Nd:YAG laser via the…
Abstract
Purpose
The objective of this study is to investigate the effect of various parameters on rapid prototyping parts for processes of sintering metallic powder by using Nd:YAG laser via the design of experiments (DOE) method.
Design/methodology/approach
Experiments based on the DOE method were utilized to determine an optimal parameter setting for achieving a minimum amount of porosities in specimens during the selective laser sintering (SLS) process. Analysis of variance (ANOVA) was further conducted to identify significant factors.
Findings
A regression model predicting percentages of porosities under various conditions was developed when the traditional Taguchi's approach failed to identify a feasible model due to strong interactions of controlled factors. The significant factors to the process were identified by ANOVA.
Research limitations/implications
Four controlled factors including pulse frequencies and pulse durations of laser beams, times of strikes of a pulse applying on a single laser spot and particle sizes of the powder base material had significant influence on the sintering process. Future investigation planned to be carried out for achieving multiple quality targets such as the hardness and the density for 3D parts.
Originality/value
The implementation of the DOE method provided a systematic approach to identify an optimal parameter setting of the SLS process; thus, the efficiency of designing optimal parameters was greatly improved. This approach could be easily extended to 3D cases by just including additional parameters into the design. Additionally, utilization of the normality analysis on the residual data ensured that the selected model was adequate and extracted all applicable information from the experimental data.
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Jun Wu, Cheng Huang, Zili Li, Runsheng Li, Guilan Wang and Haiou Zhang
Wire and arc additive manufacturing (WAAM) is a widely used advanced manufacturing technology. If the surface defects occurred during welding process cannot be detected and…
Abstract
Purpose
Wire and arc additive manufacturing (WAAM) is a widely used advanced manufacturing technology. If the surface defects occurred during welding process cannot be detected and repaired in time, it will form the internal defects. To address this problem, this study aims to develop an in situ monitoring system for the welding process with a high-dynamic range imaging (HDR) melt pool camera.
Design/methodology/approach
An improved you only look once version 3 (YOLOv3) model was proposed for online surface defects detection and classification. In this paper, improvements were mainly made in the bounding box clustering algorithm, bounding box loss function, classification loss function and network structure.
Findings
The results showed that the improved model outperforms the Faster regions with convolutional neural network features, single shot multibox detector, RetinaNet and YOLOv3 models with mAP value of 98.0% and a recognition rate of 59 frames per second. And it was indicated that the improved YOLOv3 model satisfied the requirements of real-time monitoring well in both efficiency and accuracy.
Originality/value
Experimental results show that the improved YOLOv3 model can solve the problem of poor performance of traditional defect detection models and other deep learning models. And the proposed model can meet the requirements of WAAM quality monitoring.
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Suryakumar Simhambhatla and K.P. Karunakaran
– This paper aims to develop build strategies for rapid manufacturing of components of varying complexity with the help of illustration.
Abstract
Purpose
This paper aims to develop build strategies for rapid manufacturing of components of varying complexity with the help of illustration.
Design/methodology/approach
The build strategies are developed using a hybrid layered manufacturing (HLM) setup. HLM, an automatic layered manufacturing process for metallic objects, combines the best features of two well-known and economical processes, viz., arc weld-deposition and milling. Depending on the geometric complexity of the object, the deposition and/or finish machining may involve fixed (3-axis) or variable axis (5-axis) kinematics.
Findings
Fixed axis (3-axis) kinematics is sufficient to produce components free of undercuts and overhanging features. Manufacture of components with undercuts can be categorized into three methods, viz., those that exploit the inherent overhanging ability, those that involve blinding of the undercuts in the material deposition stage and those that involve variable axis kinematics for aligning the overhang with the deposition direction.
Research limitations/implications
Although developed using the HLM setup, these generic concepts can be used in a variety of metal deposition processes.
Originality/value
This paper describes the methodology for realizing undercut features of varying complexity and also chalks out the procedure for their manufacture with the help of case studies for each approach.
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Mahesh S. Shinde, Kishor Mahadeorao Ashtankar, Abhaykumar M. Kuthe, Sandeep W. Dahake and Mahesh B. Mawale
This review paper aims to provide an overview of applications of direct rapid manufacturing assisted mold with conformal cooling channels (CCCs) and shows the potential of this…
Abstract
Purpose
This review paper aims to provide an overview of applications of direct rapid manufacturing assisted mold with conformal cooling channels (CCCs) and shows the potential of this technique in different manufacturing processes.
Design/methodology/approach
Key publications from the past two decades have been reviewed.
Findings
This study concludes that direct rapid manufacturing technique plays a dominant role in the manufacturing of mold with complicated CCC structure which helps to improve the quality of final part and productivity. The outcome based on literature review and case study strongly suggested that in the near future direct rapid manufacturing method might become standard procedure in various manufacturing processes for fabrication of complex CCCs in the mold.
Practical implications
Advanced techniques such as computer-aided design, computer-aided engineering simulation and direct rapid manufacturing made it possible to easily fabricate the effective CCC in the mold in various manufacturing processes.
Originality/value
This paper is beneficial to study the direct rapid manufacturing technique for development of the mold with CCC and its applications in different manufacturing processes.