Improving performance in POLCA controlled high variety shops: An assessment by simulation

Thürer, Matthias; Fernandes, Nuno O.; Silva, Sílvio Carmo; Stevenson, Mark

doi:10.1016/j.jmsy.2017.05.006

Cited by 17 publications

(20 citation statements)

References 32 publications

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“…In contrast, blocking is similar to Kanban and POLCA, which are decentralized and typically do not consider job workloads resulting in limited workload balancing capabilities (Germs & Riezebos, 2010). Note that another means of improving workload balancing in the context of order release is the sequence in which jobs are considered for release from the pool (Thürer et al, 2015b(Thürer et al, , 2017a(Thürer et al, and 2017b. This factor does however not affect our conclusions given the relationship between the operation due date at the first station (used to prioritize jobs subject to release blocking) and planned release dates (used to prioritize jobs in the order pool).…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Workload Control order release in general and pure flow shops with limited buffer size induced blocking: an assessment by simulation

Thürer

Stevenson

2020

International Journal of Production Research

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Most manufacturing shops in practice have limited physical space in front of each workstation, due, for example, to physical, economical or operational constraints. As a result, a job may cause blocking because it has to remain at a given station after an operation has been completed until space in front of the next station in its routing becomes available. Despite this practical reality, the Workload Control literature typically assumes infinite buffer limits and therefore neglects the impact of blocking. Using simulation, we highlight the direct, detrimental impact of blocking in both the pure and general flow shop. Workload Control order release dampens the effect of blocking and improves overall performance. This makes Workload Control order release even more important in the context of shops with blocking or physical space constraints. Further analysis reveals that the impact of blocking is less pronounced in the pure flow shop given its directed routing. Finally, most of the blocking that occurs is because jobs cannot enter the shop, i.e. there is no space in front of the gateway station. This re-emphasizes the close relationship between blocking and release methods that limit the workload, and it highlights the importance of workload balancing.

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Section: Discussion Of Resultsmentioning

confidence: 99%

Workload Control order release in general and pure flow shops with limited buffer size induced blocking: an assessment by simulation

Thürer

Stevenson

2020

International Journal of Production Research

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“…In other words, it remains unclear whether authors have actually implemented POLCA in its entirety. Meanwhile, simulation studies considering POLCA, such as by Lödding et al (2003), Fernandes & Carmo-Silva (2006), Germs & Riezebos (2010), Harrod & Kanet (2013), Farnoush & Wiktorsson (2013), Braglia et al (2014), and Thürer et al (2017), have neglected POLCA's authorization element and only modeled the card-based component. For example, Lödding et al (2003) stated that no order was hindered at release if the current operation's authorization time had not yet passed.…”

Section: Discussion Of the Polca Literaturementioning

confidence: 99%

POLC-A: an assessment of POLCA’s authorization element

et al. 2018

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POLCA (i.e. Paired-cell Overlapping Loops of Cards with Authorization) is a card-based production control approach developed to support the adoption of Quick Response Manufacturing. POLCA's control mechanism is unique since it combines a card-based element (the paired cell overlapping loops of cards) with a higher-level Material Requirements Planning (HL/MRP) system for release authorization. POLCA has been applied in practice and evaluated in research, but the loops of cards element (POLC) has been adopted without the authorization element (A). In response, we use simulation to evaluate the effect of POLCA's authorization element. We show that this element has a direct detrimental effect on percentage tardy and mean tardiness performance. While the literature argues that the authorization element should be an integral part of POLCA, our results suggest the opposite. This has important implications for research and practice. Instead of using POLCA with its authorization element, it is preferable to combine POLC the card-based elementwith a shop floor dispatching rule.

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“…As in previous simulation studies on COBACABANA (e.g., Thürer et al 2014a,b, 2019a) and POLCA (Fernandes and Carmo‐Silva 2006, Germs and Riezebos 2010, Harrod and Kanet 2013, Lödding et al 2003, Thürer et al 2017b), it is assumed that materials are available and all necessary information regarding shop floor routing and processing times is known upon the arrival of an order (job) to the shop. Once a job has arrived at the shop, it flows into the backlog to await release according to COBACABANA.…”

Section: Simulation Methodsmentioning

confidence: 99%

Material Flow Control in High‐Variety Make‐to‐Order Shops: Combining COBACABANA and POLCA

Thürer

Fernandes

Stevenson

2020

Production and Operations Management

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Material flow control mechanisms determine: (i) whether an order should be released onto the shop floor; and (ii) whether a station should be authorized to produce. Well‐known approaches include Kanban, Drum‐Buffer‐Rope (DBR), Constant Work‐in‐Process (ConWIP), Paired‐cell Overlapping Loops of Cards with Authorization (POLCA), Workload Control (WLC), and Control of Balance by Card Based Navigation (COBACABANA). The literature typically treats these approaches as competing, meaning studies argue for the superiority of one over another. However, a closer look reveals that existing mechanisms either focus on order release (ConWIP, DBR, WLC, and COBACABANA) or on production authorization (Kanban and POLCA). This study therefore calls for a paradigm shift and argues that the different mechanisms may play complementary rather than competing roles. Using simulation, we assess the performance of COBACABANA and POLCA in a high‐variety make‐to‐order shop, a type of shop arguably in most need of material flow control given the importance of throughput times and delivery time adherence. Results demonstrate that COBACABANA outperforms POLCA, but the simultaneous adoption of both control mechanisms outperforms the use of either one in isolation. More specifically, adding POLCA production authorization to COBACABANA order release enables the superfluous direct load to be further reduced, resulting in shop floor throughput time reductions of between 15% and 26% while further reducing the percentage tardy and mean tardiness by up to 14%. Compared to no material flow control, the new combined mechanism realizes a reduction of almost 50% in the percentage tardy and more than 30% in mean tardiness.

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Improving performance in POLCA controlled high variety shops: An assessment by simulation

Cited by 17 publications

References 32 publications

Workload Control order release in general and pure flow shops with limited buffer size induced blocking: an assessment by simulation

Workload Control order release in general and pure flow shops with limited buffer size induced blocking: an assessment by simulation

POLC-A: an assessment of POLCA’s authorization element

Material Flow Control in High‐Variety Make‐to‐Order Shops: Combining COBACABANA and POLCA

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