Assembly Automation

Savino, Matteo M. ; Mazza, Antonio

2015 Assembly Automation

doi: 10.1108/AA-07-2014-068

Purpose – The aim of the present work is to provide a case study where lean production (LP) techniques are implemented in a semi-automated assembly line with O-shaped (closed-loop) layout configuration. The action research has been conducted within an assembly line for automotive components. The work aims to provide insights on the impact of loop layout features with respect to lean principles’ application; operative solutions related to some logistic limit of loop layout; and how kanban technique can be adapted to an O-shaped layout. Design/methodology/approach – The main research methodology is based on action research within an assembly line of oil pumps. The two research questions find answer through literature analysis and implementation of LP in the O-shaped layout. In the A3 step, we identify the main weak points of a loop layout also under the perspective of operators’ feeling. The analysis of the main constraints is conducted in this step, with respect to the most common layout used within LP adoption. Steps A4 and A5 answer to RQ2 by an on-field results’ analysis. Findings – The use of an O-shaped layout may allow to improve ergonomic conditions for workers; to better organize parts feeding through slides and chutes because of the presence of operators outside the line. The new approach to determine the number of withdrawal kanban potentially extends the findings of Tardif et al. (2012): the minimum of the objective function is reached with a higher number of withdrawal kanbans. Research limitations/implications – The approach is applied within a stand-alone line, while in several industrial contexts, we may find several of these lines in the same shop floor. In this case, LP implementation would cope with the several kanban cards circulating, the over-saturation of the logistic operator in supplying all the lines with smaller quantities of materials. Practical implications – The action research resulted in the introduction of a new concept of supermarket, conceived as a decoupling buffer that lies near the line and in the review feeding devices, with the adoption of bins and operators’ feeding chutes. Parts’ feeding systems is reorganized with a two levels of withdrawal kanban. The introduction of line supermarket and the change of supply policies from pallets to bins contributed to the strong reduction of average work-in-progress. Yet, the double-withdrawal kanban and the small quantities supplied may cause an increase of material handling times and meters covered by operators. Social implications – Better working condition of the line operators because of the presence of ergonomic chutes for parts’ feeding. In contrast, we observed a high saturation of logistic operator because of the small quantities of components supplied on the line, with an increased stress of this worker. Originality/value – A decoupled withdrawal kanban (DWK) is developed. In DWK, the first withdrawal is issued to the supermarket that serves the line. The second withdrawal kanban is issued from the supermarket to the central warehouse. Within DWK, we propose a modified dimensioning formula through minimization of the objective function Z(k). Parts’ feeding is now organized with sliding chutes on operators’ workstations to collect components in accordance to kanban dimensioning.

Makssoud, Fatme ; Battaïa , Olga ; Dolgui, Alexandre ; Mpofu, Khumbulani ; Olabanji, Olayinka

2015 Assembly Automation

doi: 10.1108/AA-07-2014-061

Purpose – The purpose of this study is to develop a new mathematical model and an exact solution method for an assembly line rebalancing problem. When an existing assembly line has to be adapted to a new production context, the line balancing, resources allocation and component management solutions have to be revised. The objective is to minimize the number of modifications to be done in the initial line in order to reduce the time and investment needed to meet new production requirements. The proposed model is evaluated via a computational experiment. The obtained results the efficacy of the proposed method. Design/methodology/approach – This paper develops a new mathematical model and an exact solution method for an assembly line rebalancing problem with the objective to minimize the number of modifications to be done in the initial line to reduce the time and investments needed to meet new production requirements. Findings – The computational experiments show the efficacy of the proposed method. Originality/value – These reconfiguration costs were analysed for different part-feeding policies that can be adopted in an assembly line.

Bevilacqua, M. ; Ciarapica, F.E. ; De Sanctis, I. ; Mazzuto, G. ; Paciarotti, C.

2015 Assembly Automation

doi: 10.1108/AA-05-2014-035

Purpose – The purpose of this paper is to uncover the significance of quick changeovers in the packaging line of a pharmaceutical company. Using an integration of different lean practices, the study aims to reduce the batch change and changeover time up to 50 per cent, increasing overall equipment effectiveness by 25 per cent. Design/methodology/approach – The paper gives setup instructions and guidelines for preparing the standardized setup procedure without ignoring the actual constraints in a pharmaceutical company. It uses a case study to generate an integrated setup reduction approach, utilizing single-minute exchange of die tools (SMED) in combination with suppliers, inputs, process, outputs and customers (SIPOC), Kanban, 5S techniques and Total Productive Maintenance (TPM) indexes to achieve faster setups. Findings – The SMED approach helps the pharmaceutical company to eliminate unwanted activities and to externalize and reduce the internal activities by simplification or standardization. The application of other tools, such as 5S and Kanban tool-kits, allowed the company to optimize the process and reduce the standard deviation of the changeover times. Good manufacturing practice (GMP) procedures of the pharmaceutical sector limit the conversion of internal setup elements to external setup elements. Originality/value – The paper demonstrates the practical application of SMED, showing how it can bring real breakthroughs in productivity to a pharmaceutical company. Moreover, in this work, we highlight the importance of an integration of different lean practices to reduce variation in the changeover time. In particular, the standardization of setup tasks and the increased reliability in the material supply chain, in addition to reducing the changeover mean time can also reduce the standard deviation of the setup process time.

Caputo, Antonio C. ; Pelagagge, Pacifico M. ; Salini, Paolo

2015 Assembly Automation

doi: 10.1108/AA-05-2014-040

Purpose – The purpose of this paper is to develop analytical planning models to compare just-in-time (JIT) delivery and line storage (LS) alternatives for a continuous supply of materials to assembly lines. Design/methodology/approach – A mathematical model is developed to size resources and to determine total system costs. Findings – The choice of assembly lines feeding policy requires a thorough economic comparison of alternatives. However, the existing models are often simplistic, neglecting many critical factors which affect the systems’ performances. As a consequence, industries are unsure about which system is best for their environment. This model allows to compare the cost and suitability of two major continuous-supply alternatives in any specific industrial setting. Results of the model application are case-specific and cannot be generalized. Research limitations/implications – The model is aimed at single-model assembly lines operating in a deterministic environment. Although relevant quantitative cost drivers are included, some context-related qualitative factors are not yet included. The model assumes that the information about product structure and part requirements is known and that a preliminary design of the assembly system has been carried out. Practical implications – Production managers are given a quantitative decision tool to properly assess the implementation of continuous material supply policies at an early decision stage, and determine which option is the best, also allowing to explore trade-offs between the alternatives. Originality/value – With respect to previous simplified literature models, this new approach allows to quantify a number of additional factors which are critical for the successful implementation of cost-effective continuous-supply systems, including error costs. No other direct comparison of LS and JIT is available in the literature.

Limère, Veronique ; Van Landeghem, Hendrik ; Goetschalckx, Marc

2015 Assembly Automation

doi: 10.1108/AA-05-2014-043

Purpose – The purpose of this paper is to propose a decision model to choose between kitting and line stocking at the level of single parts, while taking into account the variable operator walking distances. Different ways of feeding assembly lines, such as kitting and line stocking not only have an impact on in-plant logistics flows but also determine the amount of stock that is available at the line. This, in turn, has an impact on operator walking distances during assembly. Design/methodology/approach – A mixed integer linear programming model is developed for the assignment of parts to one of both methods, and to be able to extensively test the model, an algorithm is created for the construction of representative datasets. Findings – Parts are often kitted because of a space constraint at the line, but even without a space constraint, the shorter walking distances might give preference to kitting. An analysis is presented that demonstrates how specific part characteristics influence the chances of a part being kitted. Research limitations/implications – Our research model can be extended to include, e.g., the study of alternative in-plant logistic designs and the outsourcing of kitting to a third-party logistics provider (3PL) or to the suppliers. Practical implications – The objective assignment model and the insights obtained from it are valuable for logistics and production engineers that otherwise have to rely solely on intuition. In situations with thousands of components, intuition mostly falls far short. Originality/value – First, existing models do not consider variable walking distances, which are shown to have a crucial impact on the decision. Second, the data instances created allow for a systematic comparison of future research in the field.

Kilic, Huseyin Selcuk ; Durmusoglu, Mehmet Bulent

2015 Assembly Automation

doi: 10.1108/AA-05-2014-047

Purpose – The purpose of this paper is to present a literature review on parts feeding policies and to provide the components of parts feeding systems via a classification structure. Design/methodology/approach – This paper determines the scope and components of parts feeding systems via a classification structure under three main components such as the storage of parts, transport of parts and feeding policy. Afterward, it is focused on parts feeding policies and the related papers are reviewed and analyzed according to their feeding policy types, objectives, solution methodologies and the application types. Findings – A classification structure showing the components and scope of parts feeding systems is provided. Parts feeding policies are handled in detail and feeding policy types, objectives, solution methodologies and application types in the existing studies are presented in this paper. However, the paper highlights the open research areas and advances for academics and presents applied solution methodologies and case studies for practitioners. Originality/value – This paper reveals the scope of parts feeding systems by presenting a classification structure including three main components and related subcomponents and provides a comprehensive literature review on parts feeding policies.

Caputo, Antonio C. ; Pelagagge, Pacifico M. ; Salini, Paolo

2015 Assembly Automation

doi: 10.1108/AA-02-2014-020

Purpose – The aim of this paper is to develop a detailed descriptive model for kitting operations, allowing resources sizing and computation of systems’ economic performances. Design/methodology/approach – A mathematical model allows to size resources, given product characteristics and production mix, and determines total system costs by assessing relevant cost items including investment costs (vehicles, containers, storage racks), direct operating costs (transport and kitting workforce, vehicles energy consumption and maintenance, quality costs), indirect operating costs (space requirements, work in process (WIP) and safety stock holding costs, administration and control). Findings – The choice of parts delivery supply to assembly lines requires a thorough economic comparison of alternatives. However, existing models are often simplistic and neglect many critical factors which affect the systems’ performances. As a consequence, industries are unsure about which system is best for their environment. This model allows assessment of the cost and suitability of kitting in any specific industrial setting. Results of the model application are case-specific and cannot be generalized, but the major impact of labour and error correction cost has been highlighted. Research limitations/implications – The model at present focusses on the in-house kitting systems based on travelling kits concept only. Although all quantitative cost drivers are included, some context-related qualitative decision factors are not yet included. The model assumes that the information about product structure and part requirements is known and that a preliminary design of the assembly system (i.e. line balancing) has been carried out. Practical implications – Production managers are given a quantitative decision tool to properly assess the implementation of kitting policies at an early decision stage. This allows exploring the trade-offs between the alternatives and properly planning the adoption of kitting systems, as well as comparing kitting with alternative material supply methods. Originality/value – With respect to previous simplified literature models, this new approach allows quantification of a number of additional factors which are critical for successful implementation of cost-effective kitting systems, including kitting errors. An exhaustive cost estimation of kitting systems in multiple, mixed-model assembly lines is thus permitted.

Rabbani, Masoud ; Manavizadeh, Neda ; Hosseini Aghozi, Niloofar Sadat

2015 Assembly Automation

doi: 10.1108/AA-05-2014-038

Purpose – This paper aims to consider a multi-site production planning problem with failure in rework and breakdown subject to demand uncertainty. Design/methodology/approach – In this new mathematical model, at first, a feasible range for production time is found, and then the model is rewritten considering the demand uncertainty and robust optimization techniques. Here, three evolutionary methods are presented: robust particle swarm optimization, robust genetic algorithm (RGA) and robust simulated annealing with the ability of handling uncertainties. Firstly, the proposed mathematical model is validated by solving a problem in the LINGO environment. Afterwards, to compare and find the efficiency of the proposed evolutionary methods, some large-size test problems are solved. Findings – The results show that the proposed models can prepare a promising approach to fulfill an efficient production planning in multi-site production planning. Results obtained by comparing the three proposed algorithms demonstrate that the presented RGA has better and more efficient solutions. Originality/value – Considering the robust optimization approach to production system with failure in rework and breakdown under uncertainty.

Ren, Chengyao ; Barlotti, Carmine ; Cohen, Yuval ; Frangipane, Barbara ; Garofalo, Mario ; Cozzari, Giulio ; Metz, Corey

2015 Assembly Automation

doi: 10.1108/AA-06-2014-052

Purpose – The purpose of the paper is to highlight the considerations and lessons learned from a re-layout project in an assembly area for productivity improvement. The case study took place in Bosch Rexroth Oil Control Nonantola (Italy) with satisfactory results. The paper suggests how to approach reorganization projects with focus on productivity improvements following defined targets. Design/methodology/approach – After an analysis of the initial status, the authors examine several plausible layout alternatives: the main comparison criteria and their weights are defined. Then a scoring/measuring procedure follows for the criteria of each alternative, and the alternatives are compared using principal parameters analysis (PPA). Findings – The paper lists common considerations and lessons learned in the re-layout process. Using the PPA, the authors validate the best solution for the company. Originality/value – This paper shares a valuable experience that is general enough to be shared with many other assembly systems. A unique experience combining re-layout planning, MTM and use of PPA is shared with the readers.

Yukan, Hou ; Yuan, Li ; Jie, Zhang ; Tang, Wen-Bin ; Shoushan, Jiang

2015 Assembly Automation

doi: 10.1108/AA-03-2014-025

Purpose – The purpose of this study is to present a new and relatively inexpensive method for posture evaluation of the positioning of the wing-body assembly. Positioning is an essential process to guarantee alignment accuracy in an assembly line. Design/methodology/approach – The studied method includes a structural set-up and a software algorithm used to process a set of experimental input data to compute the actual position of the wing with respect to the ideal position, which is proposed considering measurement uncertainty, the deviation caused by large errors in measurement points and the different tolerance requirements. Findings – The studied method has been found to be simple and effective in addition to being highly accurate. Compared with most of the current methods that have been developed with optical equipment, it is more cost- and space-efficient. The automation process determines how much operation time will be saved. Practical implications – The studied method has been applied in an actual assembly line, and the economic and time savings illustrate its benefits. Originality/value – This method provides an attractive wing-body assembly solution for those enterprises that want to find a low-cost option or have limited measuring space for optical equipment. It can also be the basis for the accurate assembly of other large parts for aircraft and other vessels.