Robert E. Williams, Daniel F. Walczyk and Hoang T. Dang
To determine the feasibility of sealing and finishing conformal cooling/heating channels in profiled edge laminae (PEL) rapid tooling (RT) using abrasive flow machining (AFM).
Abstract
Purpose
To determine the feasibility of sealing and finishing conformal cooling/heating channels in profiled edge laminae (PEL) rapid tooling (RT) using abrasive flow machining (AFM).
Design/methodology/approach
Sample PEL tools constructed of both aluminum and steel were designed and assembled for finishing by AFM. A simple design of experiments approach was utilized. Output parameters of interest included the material removal, surface roughness improvement and, most importantly, the ability to withstand a pressurized oil leak test.
Findings
AFM significantly improved the finish in the channels for aluminum and steel PEL tooling. Leak testing found that AFM also improved the sealing of both stacks at static pressures up to 690 kPa. The steel tooling appeared to benefit more from the AFM process. It has been postulated that the primary cause of the sealing is the plastic deformation of workpiece material in the plowing mode.
Research limitations/implications
The conformal channels studied had a simple cross‐sectional geometry and straight runs. The PEL tools were only made of two materials. However, the research results show great promise for large RT, including thermoforming and composite forming molds where temperature control is a critical issue.
Practical implications
The ability to seal the interfaces between individual laminae expands the potential application of AFM tremendously. AFM also has the potential to finish a wide range of internal passages in a variety of RT.
Originality/value
AFM has been previously used for finishing stereolithography prototypes. This is the first known attempt to seal and finish channels in laminated RT using AFM.
Details
Keywords
Jingbin Hao, Liang Fang and Robert E. Williams
Rapid prototyping (RP) of large‐scale solid models requires the stereolithographic (STL) file to be precisely partitioned. Especially, the selection of cutting positions is…
Abstract
Purpose
Rapid prototyping (RP) of large‐scale solid models requires the stereolithographic (STL) file to be precisely partitioned. Especially, the selection of cutting positions is critical for the fabrication and assembly of sub‐models. The purpose of this paper is to present an efficient curvature‐based partitioning for selecting the best‐fit loop and decomposing the large complex model into smaller and simpler sub‐models with similar‐shaped joints, which facilitate the final assembly.
Design/methodology/approach
The partition algorithm is benefited from curvature analysis of the model surface, including extracting the feature edges and constructing the feature loops. The efficiency enhancement is achieved by selecting the best‐fit loop and constructing the similar‐shape joints. The utility of the algorithm is demonstrated by the fabrication of large‐scale rapid prototypes.
Findings
By using the proposed curvature‐based partition algorithm, the reasonability and efficiency of STL model partition can be greatly improved, and the complexity of sub‐models has been reduced. It is found that the large‐scale model is efficiently partitioned and the sub‐models are precisely assembled using the proposed partitioning.
Originality/value
The curvature‐based partition algorithm is used in the RP field for the first time. Based on the curvature‐based partitioning, the reasonability and efficiency of large‐scale RP is addressed in this paper.
Details
Keywords
Robert E. Williams and Vicki L. Melton
This research investigated the use of two relatively new technologies, abrasive flow machining (AFM) and stereolithography (SL), to minimize the time to develop a finished…
Abstract
This research investigated the use of two relatively new technologies, abrasive flow machining (AFM) and stereolithography (SL), to minimize the time to develop a finished prototype. Statistical analysis was used to determine effects of media grit size, media pressure, build style, build orientation and resin type on flatness, material removal rate and surface roughness. Results indicated that media pressure, grit size, and build orientation were significant in at least one of the experiments performed. Scanning electron microscope (SEM) images showed the stair‐stepping effect of the SL process before AFM and the removal of the stair‐stepping after AFM. The SEM images showed a lack of typical AFM flowlines on the surface and suggested that the workpiece material is removed by brittle fracture. Data dependent systems analysis techniques were also used to study the surface roughness profiles.
Details
Keywords
Alexandra L. Ferrentino, Meghan L. Maliga, Richard A. Bernardi and Susan M. Bosco
This research provides accounting-ethics authors and administrators with a benchmark for accounting-ethics research. While Bernardi and Bean (2010) considered publications in…
Abstract
This research provides accounting-ethics authors and administrators with a benchmark for accounting-ethics research. While Bernardi and Bean (2010) considered publications in business-ethics and accounting’s top-40 journals this study considers research in eight accounting-ethics and public-interest journals, as well as, 34 business-ethics journals. We analyzed the contents of our 42 journals for the 25-year period between 1991 through 2015. This research documents the continued growth (Bernardi & Bean, 2007) of accounting-ethics research in both accounting-ethics and business-ethics journals. We provide data on the top-10 ethics authors in each doctoral year group, the top-50 ethics authors over the most recent 10, 20, and 25 years, and a distribution among ethics scholars for these periods. For the 25-year timeframe, our data indicate that only 665 (274) of the 5,125 accounting PhDs/DBAs (13.0% and 5.4% respectively) in Canada and the United States had authored or co-authored one (more than one) ethics article.
Details
Keywords
Communications regarding this column should be addressed to Mrs. Cheney, Peabody Library School, Nashville, Tenn. 37203. Mrs. Cheney does not sell the books listed here. They are…
Abstract
Communications regarding this column should be addressed to Mrs. Cheney, Peabody Library School, Nashville, Tenn. 37203. Mrs. Cheney does not sell the books listed here. They are available through normal trade sources. Mrs. Cheney, being a member of the editorial board of Pierian Press, will not review Pierian Press reference books in this column. Descriptions of Pierian Press reference books will be included elsewhere in this publication.
Communications regarding this column should be addressed to Mrs. Cheney, Peabody Library School, Nashville, Term. 37203. Mrs. Cheney does not sell the books listed here. They are…
Abstract
Communications regarding this column should be addressed to Mrs. Cheney, Peabody Library School, Nashville, Term. 37203. Mrs. Cheney does not sell the books listed here. They are available through normal trade sources. Mrs. Cheney, being a member of the editorial board of Pierian Press, will not review Pierian Press reference books in this column. Descriptions of Pierian Press reference books will be included elsewhere in this publication.
The following bibliography focuses mainly on programs which can run on IBM microcomputers and compatibles under the operating system PC DOS/MS DOS, and which can be used in online…
Abstract
The following bibliography focuses mainly on programs which can run on IBM microcomputers and compatibles under the operating system PC DOS/MS DOS, and which can be used in online information and documentation work. They fall into the following categories:
John H. Humphreys, Milorad M. Novicevic, Mario Hayek, Jane Whitney Gibson, Stephanie S. Pane Haden and Wallace A. Williams, Jr
The purpose of this study is to narratively explore the influence of leader narcissism on leader/follower social exchange. Moreover, while researchers acknowledge that…
Abstract
Purpose
The purpose of this study is to narratively explore the influence of leader narcissism on leader/follower social exchange. Moreover, while researchers acknowledge that narcissistic personality is a dimensional construct, the preponderance of extant literature approaches the concept of narcissistic leadership categorically by focusing on the reactive or constructive narcissistic extremes. This bimodal emphasis ignores self-deceptive forms of narcissistic leadership, where vision orientation and communication could differ from leaders with more reactive or constructive narcissistic personalities.
Design/methodology/approach
The authors argue that they encountered a compelling example of a communal, self-deceiving narcissist during archival research of Robert Owen’s collective experiment at New Harmony, Indiana. To explore Owen’s narcissistic leadership, they utilize an analytically structured history approach to interpret his leadership, as he conveyed his vision of social reform in America.
Findings
Approaching data from a ‘history to theory’ perspective and via a communicative lens, the authors use insights from their abductive analysis to advance a cross-paradigm, communication-centered process model of narcissistic leadership that accounts for the full dimensional nature of leader narcissism and the relational aspects of narcissistic leadership.
Research limitations/implications
Scholars maintaining a positivist stance might consider this method a limitation, as historical case-based research places greater emphasis on reflexivity than replication. However, from a constructionist perspective, a focus on generalization might be considered inappropriate or premature, potentially hampering the revelation of insights.
Originality/value
Through a multi-paradigmatic analysis of the historical case of Robert Owen and his visionary communal experiment at New Harmony, the authors contribute to the extant literature by elaborating a comprehensive, dimensional and relational process framework of narcissistic leadership. In doing so, the authors have heeded calls to better delineate leader narcissism, embrace process and relational aspects of leadership and consider leader communication as constitutive of leadership.