Implementing pull manufacturing in make-to-order environments

The demand for increasing product variety and customization has forced many companies to adopt a make-to-order (MTO) strategy. Traditional push-type MTO companies suffer from unstable demands, struggling to deliver on time, making them consider the utilization of pull systems to control production. In the present paper, an overview of pull systems in MTO environments is presented. Moreover, a discrete event simulation (DES) model of an MTO company in the printing and packaging industrial sector was developed and validated, in order to identify areas for improvement. DES was also used in order to evaluate the feasibility of implementing three types of pull systems: kanban, CONstant-Work-In-Process (CONWIP) and Paired Overlapping Loops of Cards with Authorizations (POLCA). The main performance indicators measured were the average WIP and the average throughput time of parts. The key findings of this project for the case study were: a) kanban is inapplicable for the current routing of parts; b) a CONWIP strategy improves the shop floor performance, but only when extra capacity is added to the extrusion workstation; c) production based on POLCA leads to the blockage of the system due to the existence of multi-routes and undirected routing

Environmental impact assessment of different strategies for the remanufacturing of user electronics

Over the years, the innovation and development of electrical and electronic equipment have been on a steep rise. Millions of electronics are being sold or discarded every year in the form of waste. Sustainable IT (Green IT or Circular Computing) is one of the most environment-friendly methods of reusing discarded or waste user electronics. The remanufacturing of a computer refers to the disassembly, repair, and upgrade of the original computer to give it a new life, along with a warranty that is as good as a new product. The goal of this work includes studying and assessing the total environmental impact of refurbishing a computer using life cycle assessment (LCA) integrated with discrete event simulation (DES), to compare two business models: (1) a case of centralized remanufacturing where the plants are in the Middle East, which is the hub for receiving waste electronics and distributing remanufactured goods; (2) a case of decentralized remanufacturing where the plants are situated in each continent for over a range of computer models. The environmental assessment was conducted using the openLCA software in combination with the WITNESS Horizon software for the DES. The results show that decentralized remanufacturing is a much more environmentally friendly option for the remanufacturing of computers, and the decentralized remanufacturing operation has a better throughput as well as efficiency, as compared to the centralized remanufacturing operation. The centralized remanufacturing scenario has a climate change impact of 1035.19 kg of CO2-Eq, as compared to the decentralized remanufacturing scenario with an impact of 816.12 kg of CO2-Eq. In terms of the impact on the marine life, decentralized remanufacturing was found to have 0.28 kg of N-Eq impact, as compared to centralized remanufacturing (0.22 kg of N-Eq). However, this does not give us a complete picture, as the environmental impact of the computer in its previous life remains unknown. Multi life cycle assessment is the assessment process that can be used to get a clearer picture of the ecological footprint of the computer during its multiple life cycles