A Comparative Study of Unbalanced Production Lines Using Simulation Modeling: A Case Study for Solar Silicon Manufacturing

In the solar silicon manufacturing industry, the production time for crystal growth is ten times longer than at other workstations. The pre-processing time at the ingot-cutting station causes work-in-process (WIP) accumulation and an excessively long cycle time. This study aimed to find the most effective production system for reducing WIP accumulation and shortening the cycle time. The proposed approach considered pull production systems, and the response surface methodology was adopted for performance optimization. A simulation-based optimization technique was used for determining the optimal pull production system. The comparison between the results of various simulated pull production systems and those of the existing solar silicon manufacturing system showed that a hybrid production system in which a kanban station was installed before the bottleneck station with a CONWIP system incorporated for the rest of the production line could reduce the WIP volume by 26% and shorten the cycle time by 16% under the same throughput conditions.

Research on collaborative task assignment method of assembly line

Purpose The purpose of this paper is to construct a task assignment model for U-shaped production lines with collaborative task, which is optimized by minimizing the number of workers and balancing the workload of the operators. The ultimate goal is to increase productivity by increasing the U-line balance and balancing the load on the operators. Design/methodology/approach First, task selection and update mechanism are analyzed and the task selection mechanism suitable for collaborative task is proposed. Second, M-COMOSAL is obtained by improving the original COMOSAL. Finally, The M-COMOSAL algorithm and the COMAOSAL algorithm are used to perform job assignment on the double-acting clutch U-shaped assembly line. Findings According to the allocation scheme obtained by M-COMSOAL, the beat can be adjusted according to the change of order demand. The final allocation scheme is superior to the COMSOAL algorithm in terms of number of workers, working time, production tempo and balance rate. In particular, compared with the old scheme, the new scheme showed a decrease of 16.7% in the number of employees and a 18.8% increase in the production line balance rate. Thus, the method is helpful to reduce the number of operators and balance the workload. Originality/value The new algorithm proposed in this paper for the assignment of collaborative task can minimize the number of workers and balance the load of operators, which is of great significance for improving the balance rate of U-shaped production lines and the utilization of personnel or equipment.

A remote MQTT-based data monitoring system for energy efficiency in industrial environments

The concept of the new industry seeks not only to improve production processes, but also to bring solutions to environmental problems, in addition to reducing resource consumption, while maintaining high yields. This constant search for process optimization has been the main agent in the development of new technologies aimed at improving the performance of industrial production lines. Thus, this article proposes to raise some important concepts of Industry 4.0, and present the development of a remote IoT-based system that, through MQTT and Modbus protocols, will be responsible for monitoring the entire electrical network of an industrial plant, sending its data to the cloud, where it can be monitored and analyzed by the industry management sector or even by an artificial intelligence system, in a simple and effective way, in real time and from anywhere, in order to assist in decision-making focused on energy efficiency.

TENSILE AND STRETCH OF PAPER FILLED WITH BACTERICIDAL ZEOLITES

The purpose of present work was to study tensile and stretch of paper prepared with the use of bactericide zeolite fillers containing up to 130 mg/g of silver, 72 mg/g of copper, and 58 mg/g of zinc, prepared by ion exchange reactions using heulandite-clinoptilolite from the Rkoni plot of the Tedzami deposit, Eastern Georgia. Filled papers with zeolite content up to 4 g/m2 and bactericidal activity confirmed by the colony forming unit assay were manufactured on the production lines of the GPM enterprise (Tbilisi, Georgia). The measured tensile strength and percentage elongation of filled paper depend on the nature of the filler and its metal content; the introduction of pure zeolite filler reduces the tensile and stretch of the paper, but fillers containing silver and copper increase the tensile strength. Accelerated aging results in lower tensile and stretch, but zeolite fillers generally make the paper more resistant to aging.

Plastic Liners for Offshore Production Lines: A Cost Effective Alternative Solution to Corrosion Resistant Alloys?

This paper presents the investigations performed by TotalEnergies and Saipem on the cost effectiveness potential of internal plastic lining for corrosion protection of offshore production lines. Objective was to better understand for a complete EPCI cost comparison the various parameters that could have a significant impact on the potential savings associated with the use of plastic lining instead of CRAs (Corrosion Resistant Alloys) for very corrosive production fluids such as sour gases. An extensive cost comparison study between CRA lining and plastic lining for offshore production lines was performed considering sensitivity on several parameters: 3 pipe diameters, S-Lay, Reel-Lay and J-Lay installation, sensitivity to external thermal insulation requirements, mechanical and design requirements, to pipe length and fixed costs (technologies and vessels). A dedicated calculation tool for system design and cost assessment was built on purpose for this sensitivity study. Costs were assessed for the various cases, starting from pipe design, then assessing procurement costs, fabrication costs then installation costs with preliminary cycle time assessment. Project management and engineering costs have been considered to obtain comparative EPCI (as installed) cost assessments for the various study cases. Plastic lining appears to be a cost-effective solution installed in J-Lay or S-Lay in addition to reeling (up to 45% of potential cost savings on installed line compared to CRA lining). The main driver for the cost savings is associated to the procurement of the pipes and associated lining, including pipe manufacturing. Some smaller savings can also be obtained from the offshore cycle times in J-Lay and S-Lay as the CRA welding add a significant operation time in comparison with standard CS welds. The fixed additional costs associated to the plastic lining (specific tooling for example) can be quickly amortized after a few kilometers thanks to the material cost savings. Integrating them as a company investment allows to unlock costs savings even for shorter lines. The thermal contribution of the plastic liner is also interesting regarding the overall pipe insulation design. This study completes the works already performed by the industry on the offshore costs of plastic lining as it considers the whole EPCI CAPEX costs from the Contractor and Operator points of view and offshore experience. The study integrates the S-Lay and J-Lay installation methods (while previous studies mainly focused on Reel-Lay) and includes an extensive sensitivity study with various key parameters such as pipe sizes, pipe design requirements, material costs and offshore operation times to get a general overview of potential benefits associated with plastic linings for offshore production lines transporting corrosive fluids such as sour gases.