Load-based generic polca: performance assessement using simulation

POLCA (i.e. Paired-cell Overlapping Loops of Cards with Authorization) is a card-based decision support system for production control, developed to support the adoption of Quick Response Manufacturing. Two variants of POLCA have been proposed in the literature to improve POLCA performance: Load Based POLCA and Generic POLCA. In this paper, we combine these two variants into a single production control system and analyse its performance for different backlog-sequencing rules. The results of a simulation study carried out for a make-to-order flow shop, support the strategy of combining these two POLCA variants and show that capacity-slack backlog sequencing based on corrected aggregate load have the potential for improving performance.info:eu-repo/semantics/publishedVersio

Systematic review and discussion of production control systems that emerged between 1999 and 2018

There exists a large literature on well-known Production Control Systems (PCS) such as Kanban, Constant Work-In-Process (CONWIP), Material Requirements Planning (MRP) and Paired Cell Overlapping Loops of Cards with Authorisation (POLCA). However, there are also many new systems that have emerged in the last 20 years. These systems are less well known, and no systematic review exists. Through a systematic literature review, 13 PCS’s were identified, such as COBACABANA, REDUTEX, BK-CONWIP and B-CONWIP. For each system, we describe its characteristics, how they work and in what productive environments it proves useful. A cross-comparison of the 13 systems was then conducted using seven variables: primary control variable (WIP or throughput), degree of centralisation, material flow (productive environment), whether it was introduced as card-based, types of authorizations, number of articles published and type of articles published (theoretical or empirical). Most new PCS’s (7 out of 13) show characteristics that are similar to Kanban, CONWIP and POLCA: they are decentralised, card-based and use WIP as primary control variable. This may be a result of the strong influence of Lean Manufacturing paradigms Meanwhile, there is a general lack of empirical studies, being 11 PCS’s developed from mathematical simulations

Order release in a workload controlled flow-shop with sequence-dependent set-up times

In this paper, we report a simulation study on the role of sequence-dependent set-up times in decision making at the order release level of a workload controlled make-to-order flow-shop. The study evaluates the potential for set-ups savings, dependent on the level of workload in the shop, for two alternative strategies, namely considering set-up times centrally, within the release decision or locally, within the dispatching decision. These strategies are compared and assessed on the basis of two main performance measures namely time in system and standard deviation of the job lateness. Results indicate that the local strategy, which has been traditionally adopted in practice and in most of the studies dealing with sequence-dependent set-up times, does not always give the best results. The release frequency and the shop workload appear critical to the selection of the strategy to adopt, strongly influencing system performance.Fundação para a Ciência e a Tecnologia (FCT)Universidade do Minh

From supply chain risk to system-wide disruptions: research opportunities in forecasting, risk management and product design

Purpose Supply chains must rebuild for resilience to respond to challenges posed by systemwide disruptions. Unlike past disruptions that were narrow in impact and short-term in duration, the Covid pandemic presented a systemic disruption and revealed shortcomings in responses. This study outlines an approach to rebuilding supply chains for resilience, integrating innovation in areas critical to supply chain management. Design/methodology/approach The study is based on extensive debates among the authors and their peers. The authors focus on three areas deemed fundamental to supply chain resilience: (1) forecasting, the starting point of supply chain planning, (2) the practices of supply chain risk management and (3) product design, the starting point of supply chain design. The authors’ debated and pooled their viewpoints to outline key changes to these areas in response to systemwide disruptions, supported by a narrative literature review of the evolving research, to identify research opportunities. Findings All three areas have evolved in response to the changed perspective on supply chain risk instigated by the pandemic and resulting in systemwide disruptions. Forecasting, or prediction generally, is evolving from statistical and time-series methods to human-augmented forecasting supplemented with visual analytics. Risk management has transitioned from enterprise to supply chain risk management to tackling systemic risk. Finally, product design principles have evolved from design-for-manufacturability to design-for-adaptability. All three approaches must work together. Originality/value The authors outline the evolution in research directions for forecasting, risk management and product design and present innovative research opportunities for building supply chain resilience against systemwide disruptions

Optimising workload norms: The influence of shop floor characteristics on setting workload norms for the workload control concept

Workload control (WLC) is a leading production planning and control (PPC) solution for small to medium sized enterprises (SMEs) and make-to-order (MTO) companies, but when WLC is implemented, practitioners find it difficult to determine suitable workload norms to obtain optimum performance. Theory has provided some solutions (e.g., based on linear programming) but, to remain optimal, these require the regular feedback of detailed information from the shop floor about the status of work-in-process (WIP), and are therefore often impractical. This paper seeks to predict workload norms without such feedback requirements, analysing the influence of shop floor characteristics on the workload norm. The shop parameters considered are flow characteristics (from an undirected pure job shop to a directed general flow shop), and the number of possible work centres in the routing of a job (i.e., the routing length). Using simulation and optimisation software, the workload norm resulting in optimum performance is determined for each work centre for two aggregate load-oriented WLC approaches: the classical and corrected load methods. Results suggest that the performance of the classical approach is heavily affected by shop floor characteristics but no direct relationship between the characteristics and norm to apply could be established. In contrast, results suggest that the performance of the corrected load approach is not influenced by shop floor characteristics and the workload norm which results in optimum performance is the same for all experiments. Given the changing nature of MTO production and the difficulties encountered with the classical approach, the corrected load approach is considered a better and more robust option for implementation in practice. Future simulations should investigate the influence of differing capacities across work centres on the workload norm while action research should be conducted to apply the findings in practice

Circular supply chain management: A definition and structured literature review

Circular economy is increasingly recognized as a better alternative to the dominant linear (take, make, and dispose) economic model. Circular Supply Chain Management (CSCM), which integrates the philosophy of the circular economy into supply chain management, offers a new and compelling perspective to the supply chain sustainability domain. Consequently, there is increasing research interest. However, a review of the extant literature shows that a comprehensive integrated view of CSCM is still absent in the extant literature. This prohibits a clear distinction compared to other supply chain sustainability concepts and hinders further progress of the field. In response, this research first classifies various terminologies related to supply chain sustainability and conceptualizes a unifying definition of CSCM. Using this definition as a base, it then conducts a structured literature review of 261 research articles on the current state of CSCM research. Based on the review results, the researchers call for further studies in the following directions that are important but received little or no attention: design for circularity, procurement and CSCM, biodegradable packaging, circular supply chain collaboration and coordination, drivers and barriers of CSCM, circular consumption, product liabilities and producer's responsibility, and technologies and CSCM