Fabrication Lead Time and Demand Variability: An Empirical Study

Author(s):  
Chien-Ho Ko ◽  
Glenn Ballard
2018 ◽  
Vol 29 (11) ◽  
pp. 943-957
Author(s):  
Sayyed Shoaib-ul-Hasan ◽  
Marco Macchi ◽  
Alessandro Pozzetti ◽  
Ruth Carrasco-Gallego

This research focuses on responsiveness in high variety manufacturing environments. To achieve it, the article proposes to develop Dynamic Response Capabilities (DRCs) of the manufacturing system defined as the abilities to readjust the planned operating parameters of workload, capacity, and lead time, in the wake of disturbances. To inform their development, built on the Workload Control theory, a routine-based framework is proposed. The framework supports an integrated approach for the implementation of adaptive decision-making routines for workload, capacity, and lead time readjustments at different stages in the order fulfilment process. Findings from two empirical cases show the appropriateness of the framework to develop and utilise DRCs in different settings of disturbances. Results of a simulation study, with one of the case companies, also shows the effectiveness of the framework to drive performance improvements in presence of recurring disturbances leading to demand variability.


Omega ◽  
2013 ◽  
Vol 41 (2) ◽  
pp. 390-396 ◽  
Author(s):  
Xin Fang ◽  
Cheng Zhang ◽  
David J. Robb ◽  
Joseph D. Blackburn

Author(s):  
Thi Ngan Pham ◽  
Albert Tan ◽  
Alvin Ang

The purpose of this article is to determine the safety stock for an omni-channel environment. The “Square Root Law” (for centralization of storage facilities) was proposed to combine the safety stock for both online and offline channels. A simulation study was conducted using a spreadsheet program and three scenarios were created based on review time, lead time and safety factor. This was based on the mean demand and standard deviation of the product's demand distribution. The study found that the sum of lead time and review time are significant in determining the amount of safety stock, and demand variability is a crucial determinant for safety stock. Recommendations are provided as guidelines for lowering the amount of safety stock in omni-channel environment.


Author(s):  
Abir Khan ◽  

This paper addressed the issues that lead up to the higher lead-time in readymade garment industries of Bangladesh. Lead-time involve the time required to deliver any good to the specified destination since receiving the order. For Bangladesh, usual lead time is 90-120 days which is very high compared to competing countries like China, Vietnam etc. This time span is prolonged by issues such as worker unrest, political instability, poor productivity, poor production planning etc. The aim of this paper was to pin point these factors and explain exactly how these issues increases the lead-time. Another objective of this study was to propose realistic solutions to the stated lead time problem. This study was conducted with a combination of quantitative and qualitative approaches. The factors working behind higher lead time and the proposed solutions are being suggested by industry experts working in the supply chain management sector. This study was conducted with hope to help the supply chain professionals working in the readymade garment industries in reducing lead-time by various SCM strategies.


Author(s):  
N. Ramkumar ◽  
P. Subramanian ◽  
T. T. Narendran ◽  
K. Ganesh

Managing inventories is crucial to the objective of minimizing supply chain costs. This paper presents an approach for setting inventory norms in context of a real-life case of an industry which practices Vendor Managed Inventory (VMI). The role of warehouses and the inventories held by them becomes significant in such an environment. This paper presents a two-phase approach to determine various components of inventory norms taking into account lead time and demand variability. Innovative strategic product classification has been done to decide upon stocking quantity at warehouses.


2011 ◽  
Vol 38 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Chien-Ho Ko

On-time delivery is a key factor in the business success of precast fabricators. The greatest obstacle to achieving this goal is demand variability. The objective of this research is to develop a plan that continuously improves production control systems for precast fabrication. This plan involves a lead time estimation model (LTEM) and schedule adjustment principles. The LTEM is established to estimate the impact of demand variability. In the model, previous jobs are analyzed as indicators of customer behavior. Using the captured behavior, fabrication lead time can be estimated for forthcoming projects. Two principles are proposed to adjust the production schedule according to the estimated lead times. Two adjustment principles are designed to reduce the impact of demand variability: (1) start fabrication later relative to the required delivery dates and (2) shift production milestones backward to the end of the production process. The effectiveness of the developed improvement plan including LTEM and the adjustment principles were validated using a real precast fabricator. The proposed approach is one of the first studies to use historical data to estimate the impacts of demand variability based on customer behavior.


2019 ◽  
Vol 11 (23) ◽  
pp. 6579 ◽  
Author(s):  
Byungsoo Na ◽  
Min Kyu Sim ◽  
Won Ju Lee

Among the many components of material delivery operations, packaging is one of the foundations of secure and cost-efficient on-time delivery. Current environmental concerns have increased the popularity of returnable packaging over disposable packaging. This study considers a supply chain in the automotive industry where a single supplier adopts returnable packages for delivery operations to a single recipient. If a returnable package is not available, then an expendable package will be used as a more expensive alternative. Thus, an investment decision on the number of returnable packages must be made prior to launching a returnable packaging system. Using the actual data from an automotive supply chain, this study conducts simulated experiments, under the uncertainty of future demand and required lead time of reverse logistics, to identify the optimal quantity of returnable packages. Sensitivity analysis is then performed by varying the assumptions on operation duration, demand variability, and lead time variability. In general, the results indicate that a greater initial purchase of returnable packages is desirable for longer operation duration, higher demand variability, and higher lead time variability. However, if operation duration is short and the uncertainty is high, then there may be little benefit in using reusable packages. These results generalize the findings from previous studies. This approach and solution can enhance reliable and efficient supply chain operations in the automotive industry and may be applied to other industries where packaging is important and expensive.


Author(s):  
Yuepeng Cheng ◽  
Bo Li ◽  
Zhenhong Li

This study considers a supply chain consisting of a supplier and an e-tailer on the internet. The e-tailer replenishes products from the supplier for private inventory and sends drop shipping requests to him for delivering orders to customers when private inventory is insufficient or stock out, whereas the supplier provides drop shipping service with a limited ability for the e-tailer. This paper proposes an algorithm to simulate the scheduling sequences of the e-tailer with the optimal threshold policy and mixture strategy in every scheduling unit and obtains the optimal threshold of private inventory for the e-tailer to achieve average profit maximization. The impacts of mixture of demand and lead time uncertainty are examined. The influence of high priority demand variability on the optimal threshold policy in two complex scenarios are also considered in this study. These results have an important guiding significance for the e-tailer who adopts the mixture strategy in e-fulfillment under complex operating environments.


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