Geometric tolerance analysis through Jacobian model for rigid assemblies with translational deviations

2016 ◽  
Vol 36 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Wilma Polini ◽  
Andrea Corrado
Keyword(s):  
Tolerance Analysis ◽  
Geometric Error ◽  
Functional Requirements ◽  
Content Type ◽  
Geometric Tolerances ◽  
Mechanical Assemblies ◽  
Geometric Deviations ◽  
2D And 3D ◽  
Practical Implications

Purpose – The purpose of this paper is to carry out a tolerance analysis with geometric tolerances by means of the Jacobian model. Tolerance analysis is an important task to design and to manufacture high-precision mechanical assemblies; it has received considerable attention by the literature. The Jacobian model is one of the methods proposed by the literature for tolerance analysis. The Jacobian model cannot deal with geometric tolerances for mechanical assemblies. The geometric tolerances may not be neglected for assemblies, as they significantly influence their functional requirements. Design/methodology/approach – This paper presents how it is possible to deal with geometric tolerances when a tolerance analysis is carried out by means of a Jacobian model for a 2D and 3D assemblies for which the geometric tolerances applied to the components involve only translational deviations. The three proposed approaches modify the expression of the stack-up function to overcome the shortage of Jacobian model that the geometric error cannot be processed. Findings – The proposed approach has been applied to a case study. The results of the case study show how, when a statistical approach is implemented, the Jacobian model with the three developed methods gives results very similar to those due to other models of the literature, such as vector loop and variational. Research limitations/implications – In particular, the proposed approach may be applied only when the applied geometrical tolerances involve translational variations in 3D assemblies. Practical implications – Tolerance analysis is a valid tool to foresee geometric interferences among the components of an assembly before getting the physical assembly. It involves a decrease of the manufacturing costs. Originality/value – The original contribution of the paper is due to three methods to make a Jacobian model able to consider form and geometric deviations.

An integrated fuzzy SWARA and fuzzy AD approach for outsourcing provider selection

2019 ◽  
Vol 30 (2) ◽  
pp. 531-552 ◽  
Author(s):  
Selçuk Perçin
Keyword(s):  
Evaluation Criteria ◽  
Decision Makers ◽  
Ratio Analysis ◽  
Functional Requirements ◽  
Content Type ◽  
Practical Applications ◽  
Chemical Company ◽  
Order Preference ◽  
Practical Implications

Purpose Unlike previous literature, this study offers a novel integrated fuzzy approach to the field of outsourcing decisions. The purpose of this paper is to use design ranges of evaluation criteria that satisfy the functional requirements (FRs) of decision makers to solve the outsourcing provider selection problem. Design/methodology/approach In this study, considering the expected significance of outsourcing evaluation criteria, and the FRs of decision makers expressed in linguistic terms, a robust multi-criteria decision-making (MCDM) tool based on the integrated use of fuzzy Step-wise Weight Assessment Ratio Analysis and weighted fuzzy axiomatic design methods is proposed for use in decision process. Findings The proposed method is applied to a Turkish chemical company. A sensitivity analysis is performed and the outcomes of the proposed integrated framework are compared with those of other MCDM methods such as fuzzy-based Technique for Order Preference by Similarity to Ideal Solution, fuzzy Vise Kriterijumska Optimizacija I Kompromisno Resenje and fuzzy Multi-Objective Optimization on the basis of Ratio Analysis. This validates the usefulness and practicality of the proposed methodology. Practical implications The main contribution of this study is that it defines specific requirements that will assist company managers in eliminating alternatives that do not satisfy the needs and expectations of their company. Originality/value This paper compares the present study with other studies in the field of manufacturing. Additionally, it provides a well-documented case study, which makes the paper of value to researchers interested in the practical applications of MCDM methods.

A variational model for 3D tolerance analysis with manufacturing signature and operating conditions

2018 ◽  
Vol 38 (1) ◽  
pp. 10-19 ◽  
Author(s):  
Andrea Corrado ◽  
Wilma Polini ◽  
Giovanni Moroni ◽  
Stefano Petrò
Keyword(s):  
Three Dimensional ◽  
Reference Value ◽  
Tolerance Analysis ◽  
Geometrical Model ◽  
Operating Conditions ◽  
Variational Model ◽  
Assembly Process ◽  
Functional Requirements ◽  
Content Type ◽  
Mechanical Assemblies

Purpose The purpose of this work is to present a variational model able to deal with form tolerances and assembly conditions. The variational model is one of the methods proposed in literature for tolerance analysis, but it cannot deal with form tolerances and assembly conditions that may influence the functional requirements of mechanical assemblies. Design/methodology/approach This work shows how to manage the actual surfaces generated by the manufacturing process and the operating conditions inside the variational model that has been modified to integrate the manufacturing signature left on the surfaces of the parts and the operating conditions that arise during an actual assembly, such as gravity and friction. Moreover, a geometrical model was developed to numerically simulate what happens in a real assembly process and to give a reference value. Findings The new variational model was applied to a three-dimensional case study. The obtained results were compared to those of the geometrical model and to those of the variational model to validate the new model and to show the improvements. Research limitations/implications The proposed approach may be extended to other models of literature. However, its limitation is that it is able to deal with a sphere–plane contact. Practical implications Tolerance analysis is a valid tool to foresee geometric interferences among the components of an assembly before getting the physical assembly. It involves a decrease in the manufacturing costs. Originality/value The main contributions of the study are the insertion of a systematic pattern characterizing the features manufactured by a process, assembly operating conditions and development of a geometrical model to reproduce what happens in a real assembly process.

Assembly tolerance analysis based on the Jacobian model and skin model shapes

2019 ◽  
Vol 39 (2) ◽  
pp. 245-253 ◽  
Author(s):  
Ting Liu ◽  
Yan-Long Cao ◽  
Qijian Zhao ◽  
Jiangxin Yang ◽  
Lujun Cui
Keyword(s):  
Product Life Cycle ◽  
Tolerance Analysis ◽  
Quality Level ◽  
Functional Requirements ◽  
Skin Model ◽  
Content Type ◽  
Kinematic Chains ◽  
Assembly Tolerance ◽  
Geometric Tolerances ◽  
Functional Features

Purpose The purpose of this paper is to carry out an assembly tolerance analysis by means of a combined Jacobian model and skin model shape. The former is based on small displacements modeling of points using 6 × 6 transformation matrices of open kinematic chains in robotics. The latter easily models toleranced features with all kinds of geometric deviations. Design/methodology/approach This paper presents the procedure of performing tolerance analysis by means of the Jacobian model and skin model shape for assemblies. The point cloud-based discrete representative is able to model the actual toleranced surfaces instead of the ideal or associated ones in an assembly, which brings the simulation tools closer to reality. Findings The proposed method has the advantage of skin model shape which is suitable for geometric tolerances management along the product life cycle and contact analysis of kinematic small variations, as well as, with the Jacobian, enabling transformation of locally expressed parts deviations to globally expressed functional requirements. The result of the case study shows the accuracy of the method. Research limitations/implications The proposed approach has not been developed fully; other functional features such as the pyramid are still ongoing challenges. Practical implications It is an effective method for supporting design, manufacturing and inspection by providing a quantitative analysis of the effects of multi-tolerances on the final functional key characteristics and for predicting the quality level. Originality/value The paper is original in taking advantages of both Jacobian model and skin model shape to consider all geometric tolerances in assembly.

Corporate acceleration process: a systems psychodynamics perspective

2020 ◽  
Vol 33 (6) ◽  
pp. 1163-1180
Author(s):  
Piotr Wójcik ◽  
Krzysztof Obłój ◽  
Aleksandra Wąsowska ◽  
Szymon Wierciński
Keyword(s):  
Open Innovation ◽  
Negative Emotions ◽  
Acceleration Process ◽  
Content Type ◽  
Team Members ◽  
Third Phase ◽  
Multiple Case ◽  
Social Defenses ◽  
Practical Implications

PurposeThe purpose of this paper is to explore the emotional dynamics of the corporate acceleration process, using the systems psychodynamics perspective.Design/methodology/approachThe study applies inductive multiple case study of embedded 10 cases of corporate acceleration, covering both incumbent and startup perspectives, occurring in the context of a corporate accelerator.FindingsWe find that (1) the process of corporate acceleration involves three phases, each of them is dominated by a different emotional state (hope, anxiety and acceptance), triggering different behavioral responses; (2) as a means to deal with negative emotions, entrepreneurs and corporate acceleration program's team members develop different mechanisms of dealing with contradictories in subsequent acceleration phases (defense and copying mechanisms), which are reflected in their behaviors. Coping mechanisms with goal reformulation (i.e. refocus from the officially declared “open innovation” goals toward mainly symbolic ones) is an effective strategy to manage negative emotions in third phase of the acceleration.Research limitations/implicationsOur sample is limited to two relatively similar accelerators established by telecom companies, and therefore, our theoretical and practical conclusions cannot be generalized.Practical implicationsWe supplement the studies of corporate accelerators that imply how to design them better and improve decision-making rules with recommendation that in order to improve their effectiveness in terms of learning and innovations, their managers need not only to learn how to manage structural and procedural differences but also how to overcome social defenses triggered by corporate–startups cooperation.Originality/valueBy documenting a multidimensional impact of acceleration process, and especially shedding light on psychodynamic aspects behind such liaisons, this paper contributes to richer understanding of corporate–startup relationships, typically examined through a rationalistic lens of strategy literature. The study contributes to interorganizational research and open innovation literature, by showing that corporate acceleration process is marked by phases based on the type of emotions intertwined with the nature and dynamism of its life cycle. It indicates how these emotions are managed depending on their type.

scholarly journals Sinabung volcano: how culture shapes community resilience

2019 ◽  
Vol 28 (3) ◽  
pp. 290-303
Author(s):  
Marta Mori ◽  
Ronan McDermott ◽  
Saut Sagala ◽  
Yasmina Wulandari
Keyword(s):  
Structured Interviews ◽  
Content Type ◽  
Aid Dependency ◽  
Relief Operations ◽  
Long Term Impact ◽  
Cultural Experts ◽  
Practical Implications

Purpose The purpose of this paper is to explore how culture, including traditions and social structures, can influence resilience and how culturally sensitive relief operations can put affected people and their context at the core of any interventions. Design/methodology/approach A case study of the Mt Sinabung volcano area in Indonesia was undertaken. As part of the case study, an analysis of interventions was conducted, which was complemented by semi-structured interviews with Karo cultural experts and humanitarian organisations. Findings Culture influences the manner in which the Karo people react to volcano eruptions with varying implications for recovery. In addition, relief organisations which understand people’s actions through a cultural lens have better managed to tailor programs with long-term impact, thereby avoiding aid dependency. Practical implications Practical examples of disaster management activities that adequately account for the beneficiaries’ way of living prior to the eruptions are provided. Aid actors are provided with guidance concerning how to better tailor their activities in line with a cultural lens. Originality/value The study provides empirical grounding for claims concerning the role of culture in planning interventions in Indonesia and other similar contexts.

The deputy principal instructional leadership role and professional learning

2017 ◽  
Vol 55 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Ann Leaf ◽  
George Odhiambo
Keyword(s):  
Instructional Leadership ◽  
Professional Learning ◽  
Ad Hoc ◽  
Team Building ◽  
Leadership Role ◽  
Instructional Leaders ◽  
Structured Interviews ◽  
Content Type ◽  
Practical Implications

Purpose The purpose of this paper is to report on a study examining the perceptions of secondary principals, deputies and teachers, of deputy principal (DP) instructional leadership (IL), as well as deputies’ professional learning (PL) needs. Framed within an interpretivist approach, the specific objectives of this study were: to explore the extent to which DPs are perceived as leaders of learning, to examine the actual responsibilities of these DPs and to explore the PL that support DP roles. Design/methodology/approach The researchers used multiple perspective case studies which included semi-structured interviews and key school document analysis. A thematic content analysis facilitated qualitative descriptions and insights from the perspectives of the principals, DPs and teachers of four high-performing secondary schools in Sydney, Australia. Findings The data revealed that deputies performed a huge range of tasks; all the principals were distributing leadership to their deputies to build leadership capacity and supported their PL in a variety of ways. Across three of the case study schools, most deputies were frequently performing as instructional leaders, improving their school’s performance through distributing leadership, team building and goal setting. Deputy PL was largely dependent on principal mentoring and self-initiated but was often ad hoc. Findings add more validity to the importance of principals building the educational leadership of their deputies. Research limitations/implications This study relied upon responses from four case study schools. Further insight into the key issues discussed may require a longitudinal data that describe perceptions from a substantial number of schools in Australia over time. However, studying only four schools allowed for an in-depth investigation. Practical implications The findings from this study have practical implications for system leaders with responsibilities of framing the deputies’ role as emergent educational leaders rather than as administrators and the need for coherent, integrated, consequential and systematic approaches to DP professional development. Further research is required on the effect of deputy IL on school performance. Originality/value There is a dearth of research-based evidence exploring the range of responsibilities of deputies and perceptions of staff about deputies’ IL role and their PL needs. This is the first published New South Wales, Australian DP study and adds to the growing evidence around perceptions of DPs as instructional leaders by providing an Australian perspective on the phenomenon. The paper raises important concerns about the complexity of the DP’s role on the one hand, and on the other hand, the PL that is perceived to be most appropriate for dealing with this complexity.

Process Signature Modeling for Tolerance Analysis

2010 ◽  
Vol 10 (2) ◽  
Author(s):  
R. Ascione ◽  
W. Polini ◽  
Q. Semeraro
Keyword(s):  
Concurrent Engineering ◽  
Manufacturing Process ◽  
Tolerance Analysis ◽  
Actual Surface ◽  
Contact Points ◽  
Geometric Tolerances ◽  
Systematic Pattern ◽  
Process Signature ◽  
Nominal Surface

Many well-known approaches exist in the literature for tolerance analysis. All the methods proposed in the literature consider the dimensional and the geometric tolerances applied to some critical points (contact points among profiles belonging to couples of parts) on the surface of the assembly components. These points are generally considered uncorrelated since the nominal surface is considered. Therefore, the methods proposed in the literature do not consider the actual surface due to a manufacturing process. Every manufacturing process leaves on the surface a signature, i.e., a systematic pattern that characterizes all the features machined with that process. The aim of the present work is to investigate the effects of considering the manufacturing signature in solving a tolerance stack-up function. A case study involving three parts has been defined and solved by means of a method of the literature, the variational method, with and without considering the correlation among the points of the same surface due to the manufacturing signature. This work represents a first step toward the integration of the design and the manufacturing in a concurrent engineering approach.

scholarly journals Innovation and cross-functional teams

2018 ◽  
Vol 24 (1/2) ◽  
pp. 84-105 ◽  
Author(s):  
Daniel Marasquini Stipp ◽  
Márcio Lopes Pimenta ◽  
Daniel Jugend
Keyword(s):  
Single Case ◽  
Field Research ◽  
Incremental Innovation ◽  
Future Research ◽  
Content Type ◽  
The Public ◽  
Tax Management ◽  
Functional Teams ◽  
Practical Implications

Purpose The aim of this paper is to characterize how innovation may happen through cross-functional teams (CFT) in an organization of the public sector. Design/methodology/approach A case study helped to characterize several behavior patterns, team structures and respective links with generating innovation in internal processes and public answering contexts. Findings The results highlight that formal-temporary teams present a higher capacity to generate incremental innovation in products, whereas permanent-informal teams have a higher capacity to generate innovation in the internal processes and public answering contexts. Research limitations/implications The limitations of this research relate to the fact that this is a single case study, and although it is an important case to examine innovation and CFTs, by its very nature, it is not possible to extend and generalize the obtained data to other organizations. The evaluation of its propositions was merely qualitative, and future research is needed to validate its characteristics. Practical implications Several settings of CFTs are presented, as well as their ability to generate different types of innovation, such as the computerization of documents, petitions and papers, which decreases the time to answer the taxpayer. Moreover, CFTs can help to create products, such as computer programs that can be used not only locally but also in several public organizations related to tax management. Originality/value The field research provides the perceptions of the respondents regarding CFT characteristics that can lead to specific types of innovation, as well as the types of products or services that can be generated by these processes.

Delivering a shared library management system for Wales

2016 ◽  
Vol 37 (6/7) ◽  
pp. 385-395 ◽  
Author(s):  
Gareth Wyn Owen
Keyword(s):  
Management System ◽  
Review Of Literature ◽  
Content Type ◽  
Implementation Phase ◽  
Library Management ◽  
First Case ◽  
Library Management System ◽  
The Uk ◽  
Practical Implications

Purpose A case study of the Wales Higher Education Libraries Forum (WHELF) project to procure and implement a shared library management system (LMS) for all universities in Wales, together with the National Health Service Libraries in Wales and the National Library of Wales. In particular, the purpose of this paper is to explore the drivers to this collaboration, outline the benefits achieved and the framework to realise further benefits. Design/methodology/approach Case study review of the process, together with a review of literature on consortia and LMSs. Findings WHELF has developed into a more mature consortium through procuring and implementing a shared LMS. The process has delivered tangible benefits and is driving more work to realise further benefits. Research limitations/implications As the WHELF Shared LMS project is only nearing the end of the implementation phase, many of the anticipated operational benefits cannot be reported. Practical implications Useful case study for other consortia or potential consortia. Originality/value WHELF is in vanguard of consortia developments in the UK, and this is the first case study of the project.

Size does matter – span of control in hospitals

2017 ◽  
Vol 31 (2) ◽  
pp. 192-206 ◽  
Author(s):  
Christina Holm-Petersen ◽  
Sussanne Østergaard ◽  
Per Bo Noergaard Andersen
Keyword(s):  
Design Methodology ◽  
Hospital Staff ◽  
Leadership Capacity ◽  
Decision Makers ◽  
Span Of Control ◽  
Content Type ◽  
Frontline Leaders ◽  
Practical Implications

Purpose Centralization, mergers and cost reductions have generally led to increasing levels of span of control (SOC), and thus potentially to lower leadership capacity. The purpose of this paper is to explore how a large SOC impacts hospital staff and their leaders. Design/methodology/approach The study is based on a qualitative explorative case study of three large inpatient wards. Findings The study finds that the nursing staff and their frontline leaders experience challenges in regard to visibility and role of the leader, e.g., in creating overview, coordination, setting-up clear goals, following up and being in touch. However, large wards also provide flexibility and development possibilities. Practical implications The authors discuss the implications of these findings for decision makers in deciding future SOC and for future SOC research. Originality/value Only few studies have qualitatively explored the consequences of large SOC in hospitals.

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