Saliha Karadayi Usta, Mehmet Kursat Oksuz and Mehmet Bulent Durmusoglu
This paper aims to propose a combined methodology to help decision makers in evaluating and selecting the most effective part feeding system.
Abstract
Purpose
This paper aims to propose a combined methodology to help decision makers in evaluating and selecting the most effective part feeding system.
Design/methodology/approach
As a first step of the methodology, a hierarchical clustering analysis is applied to design a kitting or hybrid feeding system. Second, activity-based costing methodology is applied to determine which system is better according to their costs. Besides, sensitivity analysis is implemented to observe the behavior of the system in case of the takt time changes.
Findings
Using kitting systems purely can lead to problems because of the big and expensive parts in the mixed-model assembly systems. Therefore, the hybrid feeding policy can provide better solutions for such systems.
Research limitations/implications
A case study is conducted in a company and the most produced product of the company is considered to design the part feeding system. Results indicated that transportation cost has a large proportion on the total cost and the hybrid feeding policy may be a good solution to reduce this cost.
Practical implications
The paper includes implications for the design of hybrid feeding systems in lean-based assembly lines. The proposed methodology may be a practical tool for decision makers to design and decide on the part feeding policy.
Originality/value
Kitting design has not been studied yet to the best of the authors’ knowledge. Besides, there is no certain decision methodology indicating which system is better. In this study, different methods are combined as a new methodology with the purpose of industrial decision-making.
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Ozgur Kabadurmus and Mehmet Bulent Durmusoglu
The purpose of this paper is to contribute to the lean manufacturing literature by providing a roadmap for pull production control system (PCS) implementation.
Abstract
Purpose
The purpose of this paper is to contribute to the lean manufacturing literature by providing a roadmap for pull production control system (PCS) implementation.
Design/methodology/approach
Axiomatic Design (AD) methodology is used to develop the proposed pull PCS transformation roadmap.
Findings
The proposed design methodology is validated in a real-life manufacturing system. The results show that the proposed methodology significantly reduces the design efforts. The methodology effectively helps to choose the most appropriate pull PCS and determine its operational settings with respect to the manufacturing system characteristics.
Research limitations/implications
This study presents only one case study to test the proposed methodology. In future studies, the validity of the proposed method can be further generalized in different manufacturing sectors by real-life implementations.
Practical implications
In many real-life lean production projects, companies do not know where to start or how to proceed, which leads to repetitive design efforts and inefficient designs. The developed roadmap of this study minimizes incorrect or imperfect design trials and increases the success of pull production transformation projects.
Originality/value
The implementation of pull PCS requires extensive design knowledge and expertise. Therefore, many real-life applications fail due to costly and time-consuming trial-and-error-based design efforts. In the literature, there is no comprehensive guideline or roadmap for pull PCS implementation. To address this issue, this study provides a novel holistic roadmap to transform an existing push PCS to pull. The proposed methodology uses AD principles and combines fragmentary studies of the pull production literature.
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Emre Cevikcan and Mehmet Bulent Durmusoglu
Rabbit chase (RC) is used as one of the most effective techniques in manufacturing systems, as such systems have high level of adaptability and increased productivity in addition…
Abstract
Purpose
Rabbit chase (RC) is used as one of the most effective techniques in manufacturing systems, as such systems have high level of adaptability and increased productivity in addition to providing uniform workload balancing and skill improving environment. In assembly systems, RC inspires the development of walking worker assembly line (WWAL). On the other hand, U-type assembly lines (UALs) may provide higher worker utilization, lower space requirement and more convenient internal logistics when compared to straight assembly lines. In this context, this study aims to improve assembly line performance by generating RC cycles on WWAL with respect to task assignment characteristics of UAL within reasonable walking distance and space requirement. Therefore, a novel line configuration, namely, segmented rabbit chase-oriented U-type assembly line (SRCUAL), emerges.
Design/methodology/approach
The mathematical programming approach treats SRCUAL balancing problem in a hierarchical manner to decrease computational burden. Firstly, segments are generated via the first linear programming model in the solution approach for balancing SRCUALs to minimize total number of workers. Then, stations are determined within each segment for forward and backward sections separately using two different pre-emptive goal programming models. Moreover, three heuristics are developed to provide solution quality with computational efficiency.
Findings
The proposed mathematical programming approach is applied to the light-emitting diode (LED) luminaire assembly section of a manufacturing company. The adaptation of SRCUAL decreased the number of workers by 15.4% and the space requirement by 17.7% for LED luminaire assembly system when compared to UAL. Moreover, satisfactory results for the proposed heuristics were obtained in terms of deviation from lower bound, especially for SRCUAL heuristics I and II. Moreover, the results indicate that the integration of RC not only decreased the number of workers in 40.28% (29 instances) of test problems in U-lines, but also yielded less number of buffer points (48.48%) with lower workload deviation (75%) among workers in terms of coefficient of variation.
Practical implications
This study provides convenience for capacity management (assessing capacity and adjusting capacity by changing the number of workers) for industrial SRCUAL applications. Meanwhile, SRCUAL applications give the opportunity to increase the capacity for a product or transfer the saved capacity to the assembly of other products. As it is possible to provide one-piece flow with equal workloads via walking workers, SRCUAL has the potential for quick realization of defects and better lead time performance.
Originality/value
To the best of the authors’ knowledge, forward–backward task assignments in U-type lines have not been adapted to WWALs. Moreover, as workers travel overall the line in WWALs, walking time increases drastically. Addressing this research gap and limitation, the main innovative aspect of this study can be considered as the proposal of a new line design (i.e. SRCUAL) which is sourced from the hybridization of UALs and WWAL as well as the segmentation of the line with RC cycles. The superiority of SRCUAL over WWAL and UAL was also discussed. Moreover, operating systematic for SRCUAL was devised. As for methodical aspect, this study is the first attempt to solve the balancing problem for SRCUAL design.
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Yildiz Kose, Suleyman Muftuoglu, Emre Cevikcan and Mehmet Bulent Durmusoglu
Autonomous maintenance (AM), one of the pillars of total productive maintenance (TPM), aims to achieve performance toward zero defects and zero breakdowns. AM system equipped with…
Abstract
Purpose
Autonomous maintenance (AM), one of the pillars of total productive maintenance (TPM), aims to achieve performance toward zero defects and zero breakdowns. AM system equipped with comprehensive lean tools provides continuous improvement during the AM activities. Despite its long duration, establishing a lean AM system with a robust guideline would provide significant benefits such as high quality and short lead time. Therefore, AM design approach should be provided in a holistic and detailed manner. This study aims to develop a framework for AM design, including preliminary, reactive, preventive and proactive steps using the axiomatic design (AD).
Design/methodology/approach
Requirements and technical parameters of the AM system are explored with AD. An extensive literature review and a real-life application are presented.
Findings
The proposed design was validated by adapting the proposed roadmap to a textile manufacturing system in Turkey. The application results justify the established AM system design with an average downtime improvement of 69.2% and the average elapsed time between two failures improvement of 65.1% for apparel department.
Originality/value
This study has the novelty of establishing an overall AM system design with all of its stages stepwise. It presents a comprehensive guideline in terms of integration of lean philosophy into AM design by generating maintenance-related use cases for lean tools. The developed approach facilitates creating and analyzing complex systems to improve maintenance implementations while reducing nonvalue-added operations.
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Mehmet Bulent Durmusoglu and Canan Aglan
The inherent variability on process times and demand are the factors that prevent the efficient application of lean philosophy in multi-project product development (PD…
Abstract
Purpose
The inherent variability on process times and demand are the factors that prevent the efficient application of lean philosophy in multi-project product development (PD) environments. Considering this variability, a hybrid push–pull project control system is developed, and value stream costing (VSC) analysis is performed to reflect the relation between project lead time, capacity and project cost. The assessment of the push/pull project control on lead time improvement and long-term savings on capacity have been aimed with the proposed complete design structure.
Design/methodology/approach
In a team-based structure, formed through clustering, push control techniques for planning tasks within cross-functional teams and pull control techniques for planning tasks between cross-functional teams are developed. The final step evaluates the proposed structure through VSC and long-term savings have been pointed out, especially in terms of freed-up capacity. For the validation of the proposed methodology, an office furniture manufacturing firm’s PD department has been considered and the performance of the hybrid system has been observed through simulation experiments and based on the simulation results, the lean system is evaluated by VSC.
Findings
The results of simulation experiments show a superior performance of the proposed hybrid push/pull project control mechanism under different settings of cycle time between projects or shortly project cycle time, dispatching rules within teams and variability levels. The results of the Box-Score (tool to apply VSC) indicate increased capacity in the long term to add extra projects during the planning period with the same project lead time and without additional cost.
Research limitations/implications
Although extensive simulation experiments have been performed to quantify the effect of project control structure and positive results have been reported on lead time and cost, the proposed design structure has not been tested in all existing PD environments.
Originality/value
To the best of authors’ knowledge, the quantification of the effect of hybrid project control with VSC is the first attempt to be applied in lean PD projects.
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Cem Savas Aydin, Senim Ozgurler, Mehmet Bulent Durmusoglu and Mesut Ozgurler
This paper aims to present a multi-response robust design (RD) optimization approach for U-shaped assembly cells (ACs) with multi-functional walking-workers by using operational…
Abstract
Purpose
This paper aims to present a multi-response robust design (RD) optimization approach for U-shaped assembly cells (ACs) with multi-functional walking-workers by using operational design (OD) factors in a simulation setting. The proposed methodology incorporated the design factors related to the operation of ACs into an RD framework. Utilization of OD factors provided a practical design approach for ACs addressing system robustness without modifying the cell structure.
Design/methodology/approach
Taguchi’s design philosophy and response surface meta-models have been combined for robust simulation optimization (SO). Multiple performance measures have been considered for the study and concurrently optimized by using a multi-response optimization (MRO) approach. Simulation setting provided flexibility in experimental design selection and facilitated experiments by avoiding cost and time constraints in real-world experiments.
Findings
The present approach is illustrated through RD of an AC for performance measures: average throughput time, average WIP inventory and cycle time. Findings are in line with expectations that a significant reduction in performance variability is attainable by trading-off optimality for robustness. Reductions in expected performance (optimality) values are negligible in comparison to reductions in performance variability (robustness).
Practical implications
ACs designed for robustness are more likely to meet design objectives once they are implemented, preventing changes or roll-backs. Successful implementations serve as examples to shop-floor personnel alleviating issues such as operator/supervisor resistance and scepticism, encouraging participation and facilitating teamwork.
Originality/value
ACs include many activities related to cell operation which can be used for performance optimization. The proposed framework is a realistic design approach using OD factors and considering system stochasticity in terms of noise factors for RD optimization through simulation. To the best of the authors’ knowledge, it is the first time a multi-response RD optimization approach for U-shaped manual ACs with multi-functional walking-workers using factors related to AC operation is proposed.
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Huseyin Selcuk Kilic and Mehmet Bulent Durmusoglu
– 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.
Abstract
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.
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Huseyin Selcuk Kilic and Mehmet Bulent Durmusoglu
The purpose of this paper is to develop a mathematical model for designing the kitting system by determining the optimum values of the related design parameters.
Abstract
Purpose
The purpose of this paper is to develop a mathematical model for designing the kitting system by determining the optimum values of the related design parameters.
Design/methodology/approach
Main assembly feeding systems are explained with their advantages and disadvantages. Related literature is reviewed and gaps are determined. To fill the void and to be beneficial for real life lean assembly systems, the elements of the kitting system are explained in detail and a mathematical model minimizing the cost consisting of Work In Process (WIP) and number of workers for the design of a kitting system is developed. A numerical example is presented to demonstrate the applicability of the model.
Findings
This paper provides a mathematical model that provides the required design parameters for a kitting system such as the tour period, the number of workers and the quantities of the kits by minimizing WIP and labor costs.
Originality/value
The paper provides a mathematical model for the design of a kitting system.