Research Trends and Outlooks in Assembly Line Balancing Problems

This paper presents the findings from the survey of articles published on the assembly line balancing problems (ALBPs) during 2014-2018. Before proceeding a comprehensive literature review, the ineffectiveness of the previous ALBP classification structures is discussed and a new classification scheme based on the layout configurations of assembly lines is subsequently proposed. The research trend in each layout of assembly lines is highlighted through the graphical presentations. The challenges in the ALBPs are also pinpointed as a technical guideline for future research works

Assembly line balancing with cobots: An extensive review and critiques

Industry 4.0 encourages industries to digitise the manufacturing system to facilitate human-robot collaboration (HRC) to foster efficiency, agility and resilience. This cutting-edge technology strikes a balance between fully automated and manual operations to maximise the benefits of both humans and assistant robots (known as cobots) working together on complicated and prone-to-hazardous tasks in a collaborative manner in an assembly system. However, the introduction of HRC poses a significant challenge for assembly line balancing since, besides typical assigning tasks to workstations, the other two important decisions must also be made regarding equipping workstations with appropriate cobots as well as scheduling collaborative tasks for workers and cobots. In this article, the cobot assembly line balancing problem (CoALBP), which just initially emerged a few years ago, is thoroughly reviewed. The 4M1E (i.e., man, machine, material, method and environment) framework is applied for categorising the problem to make the review process more effective. All of the articles reviewed are compared, and their key distinct features are summarised. Finally, guidelines for additional studies on the CoALBP are offered

New matrix methodology for algorithmic transparency in assembly line balancing using a genetic algorithm

© 2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/This article focuses on the Mixed-Model Assembly Line Balancing single-target problem of type 2 with single-sided linear assembly line configurations, which is common in the industrial environment of small and medium-sized enterprises (SMEs). The main objective is to achieve Algorithmic Transparency (AT) when using Genetic Algorithms for the resolution of balancing operation times. This is done by means of a new matrix methodology that requires working with product functionalities instead of product references. The achieved AT makes it easier for process engineers to interpret the obtained solutions using Genetic Algorithms and the factors that influence decisions made by algorithms, thereby helping in the later decision-making process. Additionally, through the proposed new matrix methodology, the computational cost is reduced with respect to the stand-alone use of Genetic Algorithms. The AT produced using the new matrix methodology is validated through its application in an industry-based paradigmatic example.Peer ReviewedPostprint (published version

A review of assembly line balancing optimisation with energy consideration using meta-heuristic algorithms

Energy utilisation is one of the global trending issues. Various approaches have been introduced to minimise energy utilisation especially in the manufacturing sector, which is the largest consumer sector. One of the approaches includes the consideration of energy utilisation in the Assembly Line Balancing (ALB) optimisation. This paper reviews the ALB with energy consideration from 2012 to 2020. The selected articles were limited to problems solved using meta-heuristic algorithms. The review mainly focusses on the soft computing aspect such as problem variant, optimisation objectives, energy modelling and optimisation algorithm for ALB with energy consideration. Based on the review, the ALB with energy consideration was able to reduce energy utilisation up to 11.9%. It was found that the contribution in future ALB with energy research will be human-oriented, either social factor consideration in optimisation or energy utilisation modelling for workers. In addition, the effort to introduce an algorithm with efficient performance must be pursued because ALB problems have become more complicated. The findings from this review could assist future researchers to align their research direction with the observed trend. This paper also provides the research gap and research opportunities in the future

Tabu Search Algorithm for Single and Multi-model Line Balancing Problems

This paper deals with the assembly line balancing issue. The considered objective is to minimize the weighted sum of products’ cycle times. The originality of this objective is that it is the generalization of the cycle time minimization used in single-model lines (SALBP) to the multi-model case (MALBP). An optimization algorithm made of a heuristic and a tabu-search method is presented and evaluated through an experimental study carried out on several and various randomly generated instances for both the single and multiproduct cases. The returned solutions are compared to optimal solutions given by a mathematical model from the literature and to a proposed lower bound inspired from the classical SALBP bound. The results show that the algorithm is high performing as the average relative gap between them is quite low for both problems

Intelligent robotic disassembly optimisation for sustainability using the bees algorithm

Robotic disassembly plays a pivotal role in achieving efficient and sustainable product lifecycle management, with a focus on resource conservation and waste reduction. This thesis discusses robotic disassembly sequence planning (RDSP) and robotic disassembly line balancing (RDLB), with a specific emphasis on optimising sustainability models. The overarching goal was to enhance the efficiency and effectiveness of disassembly processes through intelligent robotic disassembly optimisation techniques. At the heart of this research lies the application of the Bees Algorithm (BA), a metaheuristic optimisation algorithm inspired by the foraging behaviour of honeybees. By harnessing the power of the BA, this research aims to address the challenges associated with RDSP and RDLB, ultimately facilitating sustainable disassembly practices. The thesis gives an extensive literature review of RDSP and RDLB to gain deeper insight into the current research landscape. The challenges of the RDSP problem were addressed in this work by introducing a sustainability model and various scenarios to enhance disassembly processes. The sustainability model considers three objectives: profit, energy savings, and environmental impact reduction. The four explored scenarios were recovery (REC), remanufacture (REM), reuse (REU), and an automatic recovery scenario (ARS). Two novel tools were developed for assessing algorithm performance: the statistical performance metric (SPM) and the performance evaluation index (PEI). To validate the proposed approach, a case study involving the disassembly of gear pumps was used. To optimise the RDSP, single-objective (SO), multiobjective (MO) aggregate, and multiobjective nondominated (MO-ND) approaches were adopted. Three optimisation algorithms were employed — Multiobjective Nondominated Bees Algorithm (MOBA), Nondominated Sorting Genetic Algorithm - II (NSGA-II), and Pareto Envelope-based Selection Algorithm - II (PESA-II), and their results were compared using SPM and PEI. The findings indicate that MO-ND is more suitable for this problem, highlighting the importance of considering conflicting objectives in RDSP. It was shown that recycling should be considered the last-resort recovery option, advocating for the exploration of alternative recovery strategies prior to recycling. Moreover, MOBA outperformed other algorithms, demonstrating its effectiveness in achieving a more efficient and sustainable RDSP. The problem of sequence-dependent robotic disassembly line balancing (RDLBSD) was next investigated by considering the interconnection between disassembly sequence planning and line balancing. Both aspects were optimised simultaneously, leading to a balanced and optimal disassembly process considering profitability, energy savings, environmental impact, and line balance using the MO-ND approach. The findings further support the notion that recycling should be considered the last option for recovery. Again, MOBA outperformed other algorithms, showcasing its capability to handle more complex problems. The final part of the thesis explains the mechanism of a new enhanced BA, named the Fibonacci Bees Algorithm (BAF). BAF draws inspiration from the Fibonacci sequence observed in the drone ancestry. This adoption of the Fibonacci-sequence-based pattern reduces the number of algorithm parameters to four, streamlining parameter setting and simplifying the algorithm’s steps. The study conducted on the RDSP problem demonstrates BAF’s performance over the basic BA, particularly in handling more complex problems. The thesis concludes by summarising the key contributions of the work, including the enhancements made to the BA and the introduction of novel evaluation tools, and the implications of the research, especially the importance of exploring alternative recovery strategies for end-of-life (EoL) products to align with Circular Economy principles

The efficiency of collaborative assembling cells

To produce competitive products, it is necessary to consider their permanent modernization and adaptation to the emerging needs of a consumer. This feature of up-to-date production inevitably leads to design complexities. As a result, the complexity of a technological assembly process increases, which is a new challenge for enterprises. Simultaneously, in most cases, assembly operations are performed manually due to the complexity or impossibility of automating the assembling process for an extensive range of products. This fact is due to the insufficient flexibility of automation systems. Remarkably, this approach has significant drawbacks, i.e., low productivity and risk of chronic diseases. To solve this problem, the use of collaborative systems was proposed. Such systems have the advantages of both humans and automation tools. As a result, industrial robots can be applied as automation tools. However, when using industrial robots next to workers, the safety requirements are significantly increased since the infliction of industrial injuries is unacceptable. After considering all the above, the article deals with a new scientific and methodological approach to designing security systems of collaborative production cells and their design and effectiveness verification

Usulan Perbaikan Keseimbangan Lintasan Perakitan Departemen Assembling Menggunakan Metode RPW-MVM dan Simulasi (Kasus PT.XYZ)

PT. XYZ merupakan salah satu perusahaan manufaktur yang bergerak di bidang industri sepatu. Produk sepatu yang diproduksi oleh PT. XYZ memiliki model sepatu PDH, PDL dan Casual. Ketiga model sepatu terdiri dari terdiri dari dua bagian utama yaitu bagian upper yang merupakan bagian atas sepatu dan bagian bottom merupakan bagian bawah sepatu dan model-model sepatu tersebut melewati proses produksi yang sama sehingga jika salah satu model sepatu mengalami keterlambatan maka model yang lain akan berdampak dan mengalami keterlambatan juga yang disebabkan oleh keterlambatan pencapaian target produksi upper dan bottom sepatu. Keterlambatan pencapaian target produksi tersebut disebabkan tidak seimbangnya waktu kerja setiap stasiun kerja pada lintasan perakitan departemen assembling. Pada penelitian ini dilakukan penyeimbangan lintasan perakitan menggunakan metode RPW-MVM dan perancangan simulasi dengan menggunakan aplikasi Promodel. Setelah dilakukan penyeimbangan lintasan perakitan diperoleh hasil, penurunan jumlah stasiun kerja menjadi 13 stasiun kerja, peningkatan line efficiency bottleneck situation menjadi 88,28%, balancing efficiency meningkat menjadi 91,76% dan pertambahan output rata – rata 117 pasang sepatu.PT. XYZ merupakan salah satu perusahaan manufaktur yang bergerak di bidang industri sepatu. Produk sepatu yang diproduksi oleh PT. XYZ memiliki model sepatu PDH, PDL dan Casual. Ketiga model sepatu terdiri dari terdiri dari dua bagian utama yaitu bagian upper yang merupakan bagian atas sepatu dan bagian bottom merupakan bagian bawah sepatu dan model-model sepatu tersebut melewati proses produksi yang sama sehingga jika salah satu model sepatu mengalami keterlambatan maka model yang lain akan berdampak dan mengalami keterlambatan juga yang disebabkan oleh keterlambatan pencapaian target produksi upper dan bottom sepatu. Keterlambatan pencapaian target produksi tersebut disebabkan tidak seimbangnya waktu kerja setiap stasiun kerja pada lintasan perakitan departemen assembling. Pada penelitian ini dilakukan penyeimbangan lintasan perakitan menggunakan metode RPW-MVM dan perancangan simulasi dengan menggunakan aplikasi Promodel. Setelah dilakukan penyeimbangan lintasan perakitan diperoleh hasil, penurunan jumlah stasiun kerja menjadi 13 stasiun kerja, peningkatan line efficiency bottleneck situation menjadi 88,28%, balancing efficiency meningkat menjadi 91,76% dan pertambahan output rata – rata 117 pasang sepatu