Case Study 2: Final Assembly Operations

2015 ◽  
pp. 159-170
Keyword(s):  
Final Assembly ◽  
Assembly Operations

scholarly journals Variation Simulation of Fixtured Assembly Processes for Compliant Structures Using Piecewise-Linear Analysis

2005 ◽  
Author(s):  
Michael L. Stewart ◽  
Kenneth W. Chase
Keyword(s):  
Piecewise Linear ◽  
Element Model ◽  
Linear Analysis ◽  
Elastic Analysis ◽  
Variation Analysis ◽  
Linear Elastic ◽  
Final Assembly ◽  
Compliant Part ◽  
Assembly Operations ◽  
Variation Simulation

While variation analysis methods for compliant assemblies are becoming established, there is still much to be done to model the effects of multi-step, fixtured assembly processes statistically. A new method is introduced for statistically analyzing compliant part assembly processes using fixtures. This method yields both a mean and a variant solution, which can characterize an entire population of assemblies. The method, called Piecewise-Linear Elastic Analysis, or PLEA, is developed for predicting the residual stress, deformation and springback variation resulting from fixtured assembly processes. A comprehensive, step-by-step analysis map is presented for introducing dimensional and surface variations into a finite element model, simulating assembly operations, and calculating the error in the final assembly. PLEA is validated on a simple, laboratory assembly and a more complex, production assembly. Significant modeling issues are resolved as well as the comparison of the analytical to physical results.

Automotive Industry in BRIC Countries

2014 ◽  
pp. 55-65
Author(s):  
S. Afanas'ev ◽  
V. Kondrat’ev
Keyword(s):  
Developing Countries ◽  
Automotive Industry ◽  
Developing Economies ◽  
Cost Effective ◽  
State Regulation ◽  
Bric Countries ◽  
Final Assembly ◽  
Catching Up ◽  
The Future ◽  
Assembly Operations

For the next decade, the future of the automotive industry lies in BRIC’ countries. Together, Brazil, Russia, India, and China will account for some 30 percent of world auto sales in 2014 while also offering significant opportunities for cost-effective R&D, sourcing, and manufacturing. The authors analyze the degree of localization of leading TNC and supplies in each BRIC country, for each function, compare localization across BRIC countries, assess the future development of these markets, compare local capabilities and resources, and identify particularly promising combinations of functions and countries. Key trends in developing countries include continuing liberalization and globalization, increased foreign investment and ownership, and the increasing importance of follow-source and follow-design forces. The article concerns the trends and factors of national automotive industry formation in BRIC countries. Special emphasis is made on localization of R&D activities, final assembly operations and components production by global automotive companies in BRIC countries. It systemizes the factors of investment opportunities of different developing markets. It is concluded that active state regulation is playing the principle role in localization and catching-up process in automotive industry in developing countries. The comparison of the automotive industry in BRIC countries allows shedding light on the economic processes of emergence at large. There is a stark contrast in the capacities of development of the sector in these countries. This contrast serves as an analyzer between the modes of sector opening and the paths of technological catching-up that is the core of the phenomenon of emergence. The analysis and best practices presented in the topic, while focusing on the BRIC countries, are applicable also to other rapidly developing economies.

Product-Oriented Sensitivity Analysis for Multistation Compliant Assemblies

2006 ◽  
Vol 129 (8) ◽  
pp. 844-851 ◽  
Author(s):  
Jianpeng Yue ◽  
Jaime A. Camelio ◽  
Melida Chin ◽  
Wayne Cai
Keyword(s):  
Product Performance ◽  
Sensitivity Index ◽  
Final Assembly ◽  
Sensitivity Indices ◽  
Dimensional Variation ◽  
Product And Process ◽  
Pattern Sensitivity ◽  
Sheet Metal Assembly

Dimensional variation in assembled products directly affects product performance. To reduce dimensional variation, it is necessary that an assembly be robust. A robust assembly is less sensitive to input variation from the product and process components, such as incoming parts, subassemblies, fixtures, and welding guns. In order to effectively understand the sensitivity of an assembly to input variation, an appropriate set of metrics must be defined. In this paper, three product-oriented indices, including pattern sensitivity index, component sensitivity index, and station sensitivity index, are defined. These indices can be utilized to measure the variation influence of a pattern, an individual part, and/or component, and components at a particular station to the dimensional quality of a final assembly. Additionally, the relationships among these sensitivity indices are established. Based on these relationships, the ranges of the sensitivity indices are derived. Finally, a case study of a sheet metal assembly is presented and discussed to illustrate the applicability of these metrics.

Combining Optical Metrology and Additive Manufacturing for Efficient Manufacturing of Carbon Fiber Reinforced Plastic Orthopedics: A Case Study

2017 ◽  
Vol 871 ◽  
pp. 275-283
Author(s):  
Josefine Jahn ◽  
Benjamin Thorenz ◽  
Markus Kafara ◽  
Rolf Steinhilper
Keyword(s):  
Carbon Fiber ◽  
Optical Metrology ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Final Assembly ◽  
Reinforced Plastic ◽  
Master Pattern ◽  
Carbon Fiber Reinforced

Often, carbon fiber reinforced plastic (CFRP) manufacturing represents an expensive, time-consuming, small-scale production due to products and components characterized by complex geometric properties. In the field of orthopedic products individual molds, usually made of metal alloys or plaster, are necessary to shape the contour of the components. The presented case study focuses on individually manufactured masks for post-operative treatment of uncomplicated midfacial fractures that are frequent and typical injuries in popular contact sports like football or handball. To improve the costly process of CFRP production of individually manufactured masks, this paper describes the advantages of the combination of optical metrology (i.e. 3D-scanning) and additive manufacturing (i.e. 3D-printing). Therefore, the conventional process chain consisting of the main process steps molding (master pattern), casting (mold), CFRP laminating, curing, cutting and final assembly is replaced by 3D-scanning (instead of master pattern), followed by the revision of the CAD-model (to prevent cutting efforts), 3D-printing (mold), CFRP laminating, curing and final assembly. Summarizing, this case study on manufacturing of carbon fiber reinforced plastic orthopedics shows that the combination of innovative manufacturing technologies opens up new possibilities to increase efficiency in craft based manufacturing.

Optimizing Assembly Line Production through Line Balancing: A Case Study

2015 ◽  
Vol 761 ◽  
pp. 104-108
Author(s):  
Adi Saptari ◽  
Jia Xin Leau ◽  
M. Nor Akramin
Keyword(s):  
Cycle Time ◽  
Assembly Line ◽  
Line Balancing ◽  
Additional Increase ◽  
Line Production ◽  
System A ◽  
Line Setting ◽  
Assembly Operations ◽  
Current Systems

In Line Balancing principles, the total workload in the assembly process is divided as evenly as possible among the workstations, without violating the sequences and relations in the assembly operations. Line balancing is important in an assembly system as it balances the line and increases the efficiency, as well as the productivity of a system. A case study was conducted in the assembly line of an electrical accessories manufacturer in Malaysia. The cycle time for each station was recorded, and the standard cycle time was estimated. The productivity, as well as the efficiency of the current assembly line, were studied. In terms of the productivity, the performance of the current systems was 500 units/worker/day, while the expected productivity was 600 units/worker/day. An assembly line setting was proposed based on the Line Balancing Method; the productivity for the proposed line increased to 671 units/worker/day, or in rough additional increase around 34%.

scholarly journals A roadmap for improving the manifacture of automotive heat exchangers through value stream mapping

2019 ◽  
Author(s):  
◽  
Kate Lusiba
Keyword(s):  
Production Process ◽  
Heat Exchangers ◽  
Line Balancing ◽  
Value Stream Mapping ◽  
Automotive Manufacturing ◽  
Value Stream ◽  
Final Assembly ◽  
Work In Process ◽  
Value Stream Map

Lean manufacturing is an optimum approach for the reduction and elimination of waste within an organization. The case study company is based in South Africa and produces heat exchangers through main processes or fractals, which include pre-assembly, core building, brazing and final assembly. A walk through the plant showed that there was a large amount of inventory awaiting final assembly and that the brazing furnace often waited for material from core building. This was an indication that there could be an imbalance between the three fractals in terms of cycle time. Thus, the aim of this study was to improve the manufacturing processes for heat exchangers at the automotive manufacturing company through the deployment of value stream mapping, subsequent line balancing and developing a roadmap for reduction of waste. The case study research strategy was adopted for the study since it provided an in-depth view of phenomena. The first objective was to outline the production flow for the manufacture of automotive heat exchanger parts. The method used was a walk through the plant and observations were made to gain an understanding of the production steps from logistics production planning to shipping of the finished goods, and subsequently to a mapping-out of the production process flow was undertaken. The results showed that there was a large amount of inventory awaiting final assembly and that the brazing furnace often waited for material from core building. It was concluded that there was need to conduct a detailed process analysis to identify sources of waste. The second objective was to conduct value stream mapping for assessing the value- and non-value-adding activities in the manufacture of automotive heat exchangers components. A value stream map was developed through walking to Gemba and mapping out the production process, collecting data and pinpointing waste activities or areas to be improved. The kaizen flashes from the value stream map also revealed that operators were not fully utilizing the capacity of the bottleneck workstations. It was concluded that two instead of one planning points, and inefficiency at assembly were root causes of the high work-in-process level. The third objective was to conduct a line balancing analysis for the three production fractals. The method used was a Pareto analysis for evaluating the products, analysing the product mix and line balancing analysis of the production line. The results revealed that the furnace was run on two shifts while the subsequent assembly and preceding core building were running on three shifts causing a work-in-process build-up, thereby resulting in line imbalance. It was concluded that it was imperative to change the scheduling approach, and adopt one that prioritised and spread the cores that had relatively short cycle times, and also reduce downtime, change-over time as well as additional time for scrap and defects, and a future-state balance chart revealed that the fractals imbalance had been reduced. The fourth objective was to develop a roadmap for reduction of waste in the manufacture of car heat exchangers components. The method used was to develop proposals and assess the feasibility and cost implications of implementing each option. Recommendations were made for continuous process improvement and a roadmap for reduction of waste was proposed. In order to improve the output of assembly, training for the operators was recommended since it would also enable the removal of the second planning point at assembly. Further research could also be conducted to develop an optimal scheduling algorithm for allocation of products to work centres to ensure high utilization of work centres and reduce work-in-process inventory.

scholarly journals Integrated Synthesis of Assembly and Fixture Scheme for Properly Constrained Assembly

2004 ◽  
Author(s):  
Byungwoo Lee ◽  
Kazuhiro Saitou
Keyword(s):  
Design Method ◽  
Integrated Approach ◽  
Frame Structure ◽  
Assembly Sequence ◽  
Top Down ◽  
Initial Product ◽  
Critical Dimensions ◽  
Final Assembly ◽  
Assembly Fixture

This paper presents an integrated approach to design an assembly, fixture schemes and an assembly sequence, such that the dimensional integrity of the assembly is insensitive to the dimensional variations of individual parts. The adjustability of critical dimensions and the proper constraining of parts during assembly process are the keys in achieving the dimensional integrity of the final assembly. A top down design method is developed which recursively decomposes a lump of initial product geometry and fixture elements matching critical dimensions, into parts and fixtures. At each recursion, joints are assigned to the interfaces between two subassemblies to ensure parts and fixtures are properly constrained at every assembly step. A case study on a simple frame structure is presented to demonstrate the method.

Variation Analysis of Non-Rigid Assembly Using FEM and Fractals

2004 ◽  
Author(s):  
Xiaoyun Liao ◽  
G. Gary Wang
Keyword(s):  
New Method ◽  
The Finite Element Method ◽  
Fractal Function ◽  
New Approach ◽  
Sheet Metal Parts ◽  
Final Assembly ◽  
Influence Coefficients ◽  
Dimensional Variation ◽  
Part Variation

Many studies on the assembly of non-rigid parts suggest that the part variation affects the assembly dimensional quality. However, little is known about how the detailed microstructure of part variation influences the assembly dimensional quality. In this paper, a new method based on the finite element method (FEM) and fractal geometry is proposed to explore the influence of the part variation microstructure on the assembly dimensional variation. In the new method, a special fractal function, the Weierstrass-Mandelbrot (W-M) function, is used to extract and represent the characteristics of the part variation microstructure. FEM is applied to analyze the deformation of non-rigid parts by integrating the part variation microstructure. The contribution of the detailed part variation to the final assembly deformation is obtained by the influence coefficients method. The proposed method is implemented by using commercial software tools, ANSYS and Matlab. The proposed method is illustrated through a case study on an assembly of two flat sheet metal parts. This new approach should benefit high precision assemblies.

Product Oriented Sensitivity Analysis for Multi-Station Compliant Assemblies

2006 ◽  
Author(s):  
Jianpeng Yue ◽  
Jaime A. Camelio ◽  
Melida Chin
Keyword(s):  
Product Performance ◽  
Sensitivity Index ◽  
Final Assembly ◽  
Sensitivity Indices ◽  
Dimensional Variation ◽  
Product And Process ◽  
Pattern Sensitivity ◽  
Sheet Metal Assembly

Dimensional variation in assembled products directly affects product performance. To reduce dimensional variation it is necessary that an assembly be robust. A robust assembly is less sensitive to input variation from the product and process components such as incoming parts, subassemblies, fixtures and welding guns. In order to effectively understand the sensitivity of an assembly to input variation, an appropriate set of metrics must be defined. In this paper, three product oriented indices including pattern sensitivity index, component sensitivity index and station sensitivity index are defined. These indices can be utilized to measure the variation influence of a pattern, an individual part and/or component, and components at a particular station to the dimensional quality of a final assembly. Additionally, the relationships among these sensitivity indices are established. Based on these relationships, the ranges of the sensitivity indices are derived. Finally, a case study of a sheet metal assembly is presented and discussed to illustrate the applicability of these metrics.

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