Gijeong Seo, Md. RU Ahsan, Yousub Lee, Jong-Ho Shin, Hyungjun Park and Duck Bong Kim
Due to the complexity of and variations in additive manufacturing (AM) processes, there is a level of uncertainty that creates critical issues in quality assurance (QA), which…
Abstract
Purpose
Due to the complexity of and variations in additive manufacturing (AM) processes, there is a level of uncertainty that creates critical issues in quality assurance (QA), which must be addressed by time-consuming and cost-intensive tasks. This deteriorates the process repeatability, reliability and part reproducibility. So far, many AM efforts have been performed in an isolated and scattered way over several decades. In this paper, a systematically integrated holistic view is proposed to achieve QA for AM.
Design/methodology/approach
A systematically integrated view is presented to ensure the predefined part properties before/during/after the AM process. It consists of four stages, namely, QA plan, prospective validation, concurrent validation and retrospective validation. As a foundation for QA planning, a functional workflow and the required information flows are proposed by using functional design models: Icam DEFinition for Function Modeling.
Findings
The functional design model of the QA plan provides the systematically integrated view that can be the basis for inspection of AM processes for the repeatability and qualification of AM parts for reproducibility.
Research limitations/implications
A powder bed fusion process was used to validate the feasibility of this QA plan. Feasibility was demonstrated under many assumptions; real validation is not included in this study.
Social implications
This study provides an innovative and transformative methodology that can lead to greater productivity and improved quality of AM parts across industries. Furthermore, the QA guidelines and functional design models provide the foundation for the development of a QA architecture and management system.
Originality/value
This systematically integrated view and the corresponding QA plan can pose fundamental questions to the AM community and initiate new research efforts in the in-situ digital inspection of AM processes and parts.
Details
Keywords
Shaw C. Feng, Paul Witherell, Gaurav Ameta and Duck Bong Kim
Additive manufacturing (AM) processes are the integration of many different science and engineering-related disciplines, such as material metrology, design, process planning…
Abstract
Purpose
Additive manufacturing (AM) processes are the integration of many different science and engineering-related disciplines, such as material metrology, design, process planning, in-situ and off-line measurements and controls. Major integration challenges arise because of the increasing complexity of AM systems and a lack of support among vendors for interoperability. The result is that data cannot be readily shared among the components of that system. In an attempt to better homogenization this data, this paper aims to provide a reference model for data sharing of the activities to be under-taken in the AM process, laser-based powder bed fusion (PBF).
Design/methodology/approach
The activity model identifies requirements for developing a process data model. The authors’ approach begins by formally decomposing the PBF processes using an activity-modeling methodology. The resulting activity model is a means to structure process-related PBF data and align that data with specific PBF sub-processes.
Findings
This model in this paper provides the means to understand the organization of process activities and sub-activities and the flows among them in AM PBF processes.
Research limitations/implications
The model is for modeling AM activities and data associated with these activity. Data modeling is not included in this work.
Social implications
After modeling the selected PBF process and its sub-processes as activities, the authors discuss requirements for developing the development of more advanced process data models. Such models will provide a common terminology and new process knowledge that improve data management from various stages in AM.
Originality/value
Fundamental challenges in sharing/reusing data among heterogeneous systems include the lack of common data structures, vocabulary management systems and data interoperability methods. In this paper, the authors investigate these challenges specifically as they relate to process information for PBF – how it is captured, represented, stored and accessed. To do this, they focus on using methodical, information-modeling techniques in the context of design, process planning, fabrication, inspection and quality control.
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Keywords
Md. Rumman Ul Ahsan, Ali Newaz Mohammad Tanvir, Taylor Ross, Ahmed Elsawy, Min-Suk Oh and Duck Bong Kim
Wire + arc additive manufacturing (WAAM) uses existing welding technology to make a part from metal deposited in an almost net shape. WAAM is flexible in that it can use multiple…
Abstract
Purpose
Wire + arc additive manufacturing (WAAM) uses existing welding technology to make a part from metal deposited in an almost net shape. WAAM is flexible in that it can use multiple materials successively or simultaneously during the manufacturing of a single component.
Design/methodology/approach
In this work, a gas metal arc welding (GMAW) based wire + arc additive manufacturing (WAAM) system has been developed to use two material successively and fabricate bimetallic additively manufactured structure (BAMS) of low carbon steel and AISI 316L stainless steel (SS).
Findings
The interface shows two distinctive zones of LCS and SS deposits without any weld defects. The hardness profile shows a sudden increase of hardness at the interface, which is attributed to the migration of chromium from the SS. The tensile test results show that the bimetallic specimens failed at the LCS side, as LCS has lower strength of the materials used.
Originality/value
The microstructural features and mechanical properties are studied in-depth with special emphasis on the bimetallic interface.
Details
Keywords
This study aims to examine how students with different goals differ in their subjective well-being, including academic self-efficacy (ASE) and affect at school (AAS). There are…
Abstract
Purpose
This study aims to examine how students with different goals differ in their subjective well-being, including academic self-efficacy (ASE) and affect at school (AAS). There are four goal orientations that motivate students to achieve academic performance. Therefore, this study examined the relationship between the four dimensions of achievement goals (AGs), ASE and AAS. It also examined five relationship models between these variables.
Design/methodology/approach
This study was conducted using a survey method with a questionnaire on 516 students at several private universities in Yogyakarta who have been studying for at least two years. After testing the validity and reliability of the measurements, correlation testing was conducted to determine the relationship between the two variables. Furthermore, testing of the five relationship models was conducted using structural equation modeling (SEM) with a two-step approach.
Findings
The findings showed that each goal was directly related to students' well-being with a diverse relationship nature. Furthermore, mastery-approach goals (MApGs) were the types that most consistently have a positive effect on students' well-being. Also, performance-avoidance goals (PAvGs) consistently and negatively affected students' well-being, while performance-approach goals (PApGs) produced various influences and relationships. In addition, mastery-avoidance goals (MAvGs) are among the four AGs that still need to be studied, especially in educational settings. This is because they had no effect on ASE either directly or indirectly.
Research limitations/implications
The limitation of this study was using cross-sectional data and self-report in data collection. Furthermore, the respondents were limited to private university students, and they were few in number.
Practical implications
MApGs had a positive effect on ASE and AAS, while PAvGs can reduce ASE and cause negative effects. Therefore, higher institutions in Indonesia need to provide a curriculum that can increase students' curiosity, creativity and involvement in the learning process. This will make them confident in their abilities and have a positive attitude in school and the society. Also, this study showed that a PApG is not a negative goal because it can increase students' confidence in their abilities. This competency feeling needs to be fostered because it encourages them to increase knowledge and learning content, as well as increase their positive effects.
Originality/value
This paper addressed the need to understand how to generate and increase students’ motivation.