Quantitative modelling approaches for lean manufacturing under uncertainty

[EN] Lean manufacturing (LM) applies different tools that help to eliminate waste as well as the opera-tions that do not add value to the product or processes to increase the value of each performedactivity. Here the main motivation is to study how quantitative modelling approaches can supportLM tools even under system and environment uncertainties. The main contributions of the articleare: (i) providing a systematic literature review of 99 works related to the modelling of uncertaintyin LM environments; (ii) proposing a methodology to classify the reviewed works; (iii) classifyingLM works under uncertainty; and (iv) identify quantitative models and their solution to deal withuncertainty in LM environments by identifying the main variables involved. Hence this article pro-vides a conceptual framework for future LM quantitative modelling under uncertainty as a guide foracademics, researchers and industrial practitioners. The main findings identify that LM under uncer-tainty has been empirically investigated mainly in the US, India and the UK in the automotive andaerospace manufacturing sectors using analytical and simulation models to minimise time and cost.Value stream mapping (VSM) and just in time (JIT) are the most used LM techniques to reduce wastein a context of system uncertainty.The research leading to these results received funding fromthe project 'Industrial Production and Logistics Optimizationin Industry 4.0' (i4OPT) (Ref. PROMETEO/2021/065) granted by the Valencian Regional Government; and grant PDC2022-133957-I00 funded by MCIN/AEI /10.13039/501100011033 and by European Union Next Generation EU/PRTR.Rojas, T.; Mula, J.; Sanchis, R. (2023). Quantitative modelling approaches for lean manufacturing under uncertainty. International Journal of Production Research. 1-27. https://doi.org/10.1080/00207543.2023.229313812

Application of the single-minute exchange of die system to the CNC sector of a shoe mold company

The aim of this work is to present a quantitative evaluation of the benefits of applying the Single-Minute Exchange of Die (SMED) implemented in a shoe mold company. Based on the application of this methodology, we noticed that real gains were obtained with very little financial investment. The improvements observed in the sector were the reduction of set-up time by 60%, with an average set-up time of approximately 7 min, and an increase in the productive capacity of the sector by around 3%. There was a reduction in the incidence of errors in the machined parts due to the standardization of the processes performed by the operators. Among the advantages presented with the new system are reduced material exchange time, reduced time spent fine-tuning, less chance of errors during exchanges, improved product quality, greater reliability with respect to reduction of dissociation stocks and the flexibilization of the production system

Application of the SMED methodology through folding references for a bus manufacturing company

Bodywork assembly in bus manufacturing is a task that involves several operations. In Mex- ico, many bus manufacturing companies have non-flexible production lines, which makes model change very problematic. In response to this situation, the SMED methodology was applied to make more flexible production lines in terms of setup reduction for model chang- ing. In this paper, the urban bus assembly line was studied, which is composed of sub-assem- bly stations that subsequently feed the station that assembles the unit, and that joints all the frames of the required model, the aim of the paper is to propose an approach to reduce the production time through the use of folding references. With the application of the SMED, it was observed that the production line improved in the transition from one body structure model to another, obtaining results of 56.2% in the time reduction

Data-Driven Process Optimization of Additive Manufacturing Systems

The goal of the present dissertation is to develop and apply novel and systematic data-driven optimization approaches that can efficiently optimize Additive Manufacturing (AM) systems with respect to targeted properties of final parts. The proposed approaches are capable of achieving sets of process parameters that result in the satisfactory level of part quality in an accelerated manner. First, an Accelerated Process Optimization (APO) methodology is developed to optimize an individual scalar property of parts. The APO leverages data from similar—but non-identical—prior studies to accelerate sequential experimentation for optimizing the AM system in the current study. Using Bayesian updating, the APO characterizes and updates the difference between prior and current experimental studies. The APO accounts for the differences in experimental conditions and utilizes prior data to facilitate the optimization procedure in the current study. The efficiency and robustness of the APO is tested against an extensive simulation studies and a real-world case study for optimizing relative density of stainless steel parts fabricated by a Selective Laser Melting (SLM) system. Then, we extend the idea behind the APO in order to handle multi-objective process optimization problems in which some of the characteristics of the AMabricated parts are uncorrelated. The proposed Multi-objective Process Optimization (m-APO) breaks down the master multi-objective optimization problem into a series of convex combinations of single-objective sub-problems. The m-APO maps and scales experimental data from previous sub-problems to guide remaining sub-problems that improve the solutions while reducing the number of experiments required. The robustness and efficiency of the m-APO is verified by conducting a series of challenging simulation studies and a real-world case study to minimize geometric inaccuracy of parts fabricated by a Fused Filament Fabrication () system. At the end, we apply the proposed m-APO to maximize the mechanical properties of AMabricated parts that show conflicting behavior in the optimal window, namely relative density and elongation-toailure. Numerical studies show that the m-APO can achieve the best trade-off among conflicting mechanical properties while significantly reducing the number of experimental runs compared with existing methods

Reducing land take and energy use of high-speed railways through the robust design of operations

I address the problem of the high capital cost of high-speed railways and the need to reduce their energy use through the design of robust operations at the planning stage. Given the cost structure and benefits of different solutions, reducing the size of termini and maintaining robust operations in and near the termini is identified as a promising option for cost reduction. Two methodologies from manufacturing industry, namely, the Lean principle for cost reduction and the Taguchi method for robust design, are confirmed as suitable tools to realise the objective of improving the design of high-speed railways. I developed a novel approach that combines Lean and Taguchi techniques to deal with characteristic features of high-speed railways, such as the severe requirement for robust operations. Finally, the worth of the combined approach has been demonstrated by means of case studies of current British conventional railway practice, current Japanese high-speed railway operations and the planned High Speed Two (HS2) line. The latter work has shown the possibility of a reduction in the proposed number of platforms at Euston Station, the main terminus of HS2 in London, as well as energy saving for traction

Overall Equipment Effectiveness: Systematic Literature Review and Overview of Different Approaches

Overall equipment effectiveness (OEE) is a key performance indicator used to measure equipment productivity. The purpose of this study is to review and analyze the evolution of OEE, present modifications made over the original model and identify future development areas. This paper presents a systematic literature review; a structured and transparent study is performed by establishing procedures and criteria that must be followed for selecting relevant evidences and addressing research questions effectively. In a general search, 862 articles were obtained; after eliminating duplicates and applying certain inclusion and exclusion criteria, 186 articles were used for this review. This research presents three principal results: (1) The academic interest in this topic has increased over the last five years and the keywords have evolved from being related to maintenance and production, to being related to lean manufacturing and optimization; (2) A list of authors who have developed models based on OEE has been created; and (3) OEE is an emerging topic in areas such as logistics and services. To the best of our knowledge, no comparable review has been published recently. This research serves as a basis for future relevant studies

An Integration of Kano Model, QFD and Six Sigma to Present a New Description of DFSS

Business competitiveness is no longer a choice but a matter of survival in global market place. For any company, the continuous and timely development of new products and services, which include creative features that are expected to satisfy customers, is essential to remain competitive. At present, the companies not only focus on customer satisfaction, but also want to please them that ultimately lead them towards loyalty in future. Therefore, in-depth and quick understanding of the dynamic needs of customers can be important in the development of products and markets through a short period of time. However, there have been numerous failures in product development efforts leading towards enormous waste of time and resources. One of the reasons for this is the lack of a structured and comprehensive process for product development that utilizes powerful models and methodologies, such as Kano model, QFD and modern QI methodologies as well as the principles of concurrent engineering including cross-functional teams and timely communication. As all these methodologies share the same goals of pursuing customer satisfaction thus their integration into a common model is possible and beneficial Kano model strengthens the modern QI methodologies such as Six Sigma or Lean Six Sigma approach and further enhances customers’ satisfaction level. Six Sigma is used to achieve high-levels of stability through reduction in process and product variation. This directs to an almost defect free level which is also the focus of DFSS (or DMADV) building quality upstream for existing products and new product development methods. This level is essential to the customer, but not necessarily economic. Therefore, it is important to understand the customer's needs and requirements of the target, and understanding about company's own capabilities and costs. In addition to integrating Kano model and QFD into Six Sigma, the proposed approach extends previous works on these models. This paper presents a new description of the DFSS structured approach including a simple way for calculating the degree of importance for customer requirements with the adoption of Kano factor (K).An integrated approach for DFSS is proposed for practitioners to strategically understand the VOC. It included the use of different powerful tools such as Kano model, QFD, Taguchi’s QLF, TRIZ, AHP, DOE, SIPOC and FMEA. All of these tools are relevant and have consensus in terms of solving customer problems to achieve customer satisfaction. They also complement each other and can be integrated together, within DFSS, to form a better methodology. Therefore, the integration of these tools for the DFSS method is considered to be possible and useful. This work extended the previous works regarding these tools, included new ideas and incorporated them in a new model. Kano model lies in the center of the framework as it forms a basis for a profound understanding of the customer needs. The DFSS methodology utilizes Deming’s PDCA cycle through the DMADV phases for Cl. Kano model strengthens DFSS and brings an intelligent approach to understand and prioritize customer requirements. In addition, a generic case study is used to demonstrate some of the steps in the proposed methodology about how it can be implemented. Keywords: Kano model, QFD, QI, Six Sigma, VOC, DFSS, QLF, FMEA, CI, DMADV, SIPOC, Customer satisfaction, product developmen

Ergonomik risk değerlendirme ve gri esaslı taguchi yöntemleri ile bir smed yaklaşımı önerisi ve uygulaması

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu çalışmada, atölye içerisindeki duruşların tespit edilip en fazla duruş süresine neden olan kurulum işlemi üzerinde çalışma yaparak üretim verimliliğini ve çalışanların ergonomik olarak verimliliğini arttırarak daha etkin bir süre kısaltması amaçlanmaktadır. Yapılan çalışmada iki yenilik söz konusudur. İlk olarak Tekli Dakikalarda Kalıp Değişimi (SMED) yöntemine göre süre azaltma yapıldıktan sonra, ergonomik risk değerlendirme yöntemlerinden Sue Rodgers yöntemi esas alınarak yeni SMED yaklaşımı geliştirilmiştir. Kurulum proses bileşenlerinde sürenin kısaltılması için makine ile ilgili iyileştirmeler yapılırken ergonomik risk değerlendirmesi de yapılarak işin insan vücudundaki temel organlarda oluşturduğu risk değerlendirilmesi yapılacaktır. Risk, yorulma ve yaralanma ile ilgili olacaktır. Önerilen risk azaltma faaliyetleri ile yorulmanın azalması sağlanacak böylece hem işlem süresi uzamayacak hem de yaralanmalardan dolayı yavaşlama veya iş yapamama durumları ortadan kalkacağı için daha etkin süre iyileşmesi elde edilecektir. Riskin azaltılmasının beraberinde işin yapılış süresini de azaltacağı öngörülmektedir. Ancak bazı proses bileşenlerinde geleneksel SMED uygulamaları ile etkin bir iyileşme elde edilememesi söz konusu olabilmektedir. Bu gibi durumlarda bazı iyileştirme yöntemlerinden yararlanmak gerekir. Çalışmadaki ikinci yenilik ise iyileştirmenin gerçekleştirilemediği veya çok az iyileştirme beklenen bir proses bileşeninde süre ve ergonomik riski aynı anda azaltarak iyileşme elde etmek amacıyla deney tasarımı uygulamasıdır. İyileştirilmesi gereken süre ve risk gibi iki değer olduğundan bunun için çok yanıtlı Taguchi yöntemlerinden Gri esaslı Taguchi yöntemi kullanılmıştır. Bu çalışmada geleneksel SMED uygulaması ile süresi kısaltılamayan ve risk seviyesi yüksek olan ortak bir proses bileşeninde Gri esaslı Taguchi yöntemi ile daha etkin sonuç elde edilebileceği gösterilmektedir. Geliştirilen modelin uygulanması ile ilk durumda 196 dakika olan kurulum işlem süresi son durumda 73,5 dakikaya ulaşmış ve %62,5 değerinde bir iyileştirme elde edilmiştir.In this study, the posture detected in the workshop to a maximum downtime caused by increasing the efficiency of production efficiency and ergonomically employees working on making the setup process is intended to more effectively shortening time. In this research, there are two innovations. The first single minutes exchange of dies (smed) time reduction is made according to the method, after the method of ergonomic risk assessment methods on the basis of the new smed approach was developed by Sue Rodgers. The shortening of the duration of steps in the installation process while making improvements to the machine for ergonomic risk assessment will be done to essential organs in the human body and the risk of work will be evaluated. Risk will be related to fatigue and injury. Being tired with the activities proposed risk mitigation will decrease, thus, will lengthen the processing time and also a slowdown because of injuries or inability to work will be obtained more effective situations will be eliminated because the time to heal. With the reduction of the risk it is envisaged that the work will reduce the time of construction. However, some improvement can be attained with an effective SMED process steps in traditional applications. In such cases, the method should take advantage of some improvement. The second innovation in the study could not be performed to improve the time and very little improvement to be expected by reducing ergonomic risk in the process components at the same time the application of experimental design in order to achieve the improvement. Improving takes time and risk, such as grey taguchi method for multiple answers, because this two is the value-based Taguchi method was used. This study shows, more effective results can be obtained with the traditional SMED applications with time can not be shortened and the high level of risk based on a common process step grey with Taguchi method. At the same time the high level of risk on employees with ergonomic risk level and component of the process to reduce the time available by appropriate factors to identify those factors experimental setup process step of forming the current setup time has been shown to be reduced. With the implementation of the developed model, in the first case,196 minutes the installation processing time reached 73,5 minutes and the final state is obtained an improvement value of 62,5%

Production management model to reduce non-fulfillment of orders in Peruvian garment SMEs through 5S, SMED and standardization tools

Currently, formal SMEs in the textile sector represent 16.4% of Peru's manufacturing SMEs, in other words, there are approximately 32,137 companies in this sector. The textile industry is the third largest contributor to manufacturing and is intensive in the generation of approximately 400,000 direct jobs. However, one of the main problems that prevents it from competing effectively with other countries in the region is related to non-fulfillment of orders. Also, lack of communication in the organization, inadequate operator training and employee resistance to new changes are the main barriers faced by companies in the sector during lean implementation. This research study will focus on reducing order non-compliance in an SME in the apparel sector using 5s techniques, SMED and standardization. An improvement is expected in relation to the problem, in addition, it is intended to develop a framework of lean practices that will serve companies in the sector. In this way, it contributes to the existing literature

A clustering based matrix for selecting optimal tools and techniques in quality management

The purpose of this research was to explore a systematic pattern for selecting quality tools and techniques in the manufacturing and service industries. This study asked, “What are the best DMAIC tools and techniques concerning circumstances of quality dimensions of products and services?” To answer this question, this research developed innovative, diagnostic matrices by mimicking the contradiction matrix of the Theory of Inventive Problem Solving (TRIZ). These innovative matrices are intended to help non-expert users to select the best sets of quality tools and techniques for solving different quality problems. By conducting a cluster analysis, the researcher uncovered homogeneous patterns of enough quality case studies, which ultimately provided the basis for selecting optimal groups of quality tools and techniques in different circumstances. Thus, the researcher examined the association and prevalence of different quality tools and techniques (independent variables) and the quality dimensions (dependent variables). The study developed the contradiction matrix for manufacturing, which includes the optimal 17 DMAIC lists of tools and techniques. Also, the study developed the contradiction matrix for service, which ultimately includes the optimal 15 DMAIC lists of tools and techniques. After developing and verifying the developed contradiction matrices, the researcher discussed their strengths and limitations as well as their roles for selecting the appropriate quality tools and techniques in the manufacturing and service industries. The results of this research can be used as a basis for many future investigations in the field of quality management and innovation