Process mapping, modelling and optimization of plant layouts and materials handling in manufacturing

Abstract: Documenting process flows in a manufacturing environment provides a guide to understanding how processes are interconnected and how materials are handled, thus forming the basis for modelling and optimization in order to simplify the otherwise complex systems particularly in multi-product manufacturing. Research was carried out at a furniture manufacturing company specializing in the production of a wide range of furniture from hardwood. Owing to the multiplicity of processes and the movement of materials in manufacturing environments, the factors affecting such setups increasingly become complex, equally requiring complex techniques to analyze and optimize them. A work study carried out at the company established inherent problems that affected production and were used as the basis for modelling and optimizing the processes, focusing on grouping of workstations depending on functions, predicting performance using simulation and machine distance matrices for a reorganized plant layout. Results obtained after modelling and optimizing the plant layout were useful for production planning and control as well as enhancing the company’s productivity and efficiency

Process mapping and optimization of the process flows of a furniture manufacturing company in Zimbabwe using machine distance matrices

Abstract: Appropriate arrangement of machinery in a manufacturing environment can have a positive impact on the productivity of a company. A detailed work study carried out at a furniture manufacturing company revealed that parts travelled long distances before the final product is produced owing to the positions of machinery and crisscrossing process flows. This paper looks at how the plant layout was re-organized by mapping process flows and regrouping of the machinery according to their functions and products using machine distance matrices. Challenges relating to the plant layout, process flows, materials handling and transportation as well as assembly procedures were established, coupled with grouping machines according to functions and the least distance between interacting workstations. Using the machine distance matrices, processes were mapped and equipment reorganized to allow for continuous flow of production, resulting in significant reductions in transportation distances among interacting workstations and elimination of crisscrossing process paths

Smart and strategic procurement, use and maintenance partnerships in engineering equipment for sustainable development and training in Sub-Saharan Africa using a systems thinking approach

Abstract: Most engineering institutions in Sub-Saharan Africa generally suffer from the persistent shortage and lack of accessibility to modern engineering equipment for the training of engineers. The old and obsolete equipment available, invariably pose challenges on the caliber of engineers being churned out to run industries in these developing countries. Based on research carried out at four engineering institutions in Sub-Saharan Africa through data collection and analysis, a smart procurement, use and maintenance strategy in the form of strategic partnerships with industry was formulated using a systems thinking approach. This paper looks at the development of this strategy and how the proposed partnerships can help in sustainable development, capacity building and ultimately bridging the gap between industry and academia. The implementation of this novel approach at the University of Zimbabwe has brought immense benefits such as students and staff access to modern equipment and technology

Design of a 10-digit inventory codification system for a tube and pipe manufacturing company in Zimbabwe

Abstract: Lack of proper inventory control usually leads to high stock-outs resulting in ‘firefighting’. This paper looks at the engineering and technical services required to maintain smooth production with the aim of developing an inventory control system for the efficient utilization of resources. A work study was carried out at a tube and pipe manufacturing company in Zimbabwe followed by an analysis outlining the operations, limitations and process flows. An inventory audit provided some insights on the company’s inventory control status. A 10-digit inventory codification system was designed based on 7 rules for generic application and capability for ‘make or buy’ decisions on spare parts. A cost benefit analysis revealed that although the project would initially be costly, a reduction in inventory can be realized through removal of slow moving and obsolete stock, realizing some annual savings in the long run, coupled with an improvement in record keeping and accountability.Lack of proper inventory control usually leads to high stock-outs resulting in ‘firefighting’. This paper looks at the engineering and technical services required to maintain smooth production with the aim of developing an inventory control system for the efficient utilization of resources. A work study was carried out at a tube and pipe manufacturing company in Zimbabwe followed by an analysis outlining the operations, limitations and process flows. An inventory audit provided some insights on the company’s inventory control status. A 10-digit inventory codification system was designed based on 7 rules for generic application and capability for ‘make or buy’ decisions on spare parts. A cost benefit analysis revealed that although the project would initially be costly, a reduction in inventory can be realized through removal of slow moving and obsolete stock, realizing some annual savings in the long run, coupled with an improvement in record keeping and accountability

Modelling, simulation and optimization of the materials flow of a multi-product assembling plant

Abstract: Various dynamic factors impact the movement of materials within a manufacturing environment, increasingly becoming complex for multi-product assembling plants owing to the multiplicity and interconnectedness of these factors. Analyzing these factors can be equally complex, requiring modelling and simulation tools. This paper looks at the modelling and simulation of the materials flow of a multi-product furniture assembling plant to develop an efficient system that accomplishes timely product deliveries at minimal cost. Generic simulation models based on 2 products were developed and constructed using Arena® Simulation Software. Following the simulation experiments and implementation of the results, the average hourly throughput was significantly increased and additional space to store materials prior to processing at workstations was created. The generic models were compatible with the company's other products and hence useful for the company’s production planning and scheduling

Optimization of a plant layout and materials handling system for a furniture manufacturing company

Abstract: The proper layout and efficient utilization of resources; human, machinery and space can have a positive bearing on the productivity of manufacturing companies. A case study was carried out at a furniture manufacturing plant in Harare, Zimbabwe and this paper presents the findings and proposals for an optimized plant layout and materials handling system. Inherent problems within the manufacturing setup were identified through the use of questionnaires and the company’s available documentation. These ranged from crisscrossing process flows, undocumented production plans and inadequately planned materials processing and handling. Following a detailed work study, production planning and control techniques for materials handling, processing and assembly were introduced to improve production throughput times. Three alternative models were conceptualized and the best model was selected using the payback period method while optimization of the plant was achieved through a novel approach of process mapping of the layout, available space and materials handling machinery. Results obtained from the assessment of the selected model revealed that transportation distances can be reduced significantly while production throughput time decreases

Nonlinear finite element program for reinforced concrete structural control

Abstract: Proprietary softwares are often used for structural control in engineering. Nonlinear structural control researches often uses nonlinear finite element toolbox (NLFET) code which was specifically developed for coding and simulations of structures. This paper provides an overview of the use of NLFET including the data structures and algorithms used to develop a nonlinear finite element program for reinforced concrete structural control. In order to make use of the nonlinear routines, powerful control and NLFET toolboxes, NFLET are implemented in MATLAB. The data of the structure is stored in MATLAB structures for maximum flexibility and to improve the readability of the code. Object oriented design is used to define element types so that new elements (both linear and nonlinear) can be added easily and without necessitating changes in the core analysis code. Solidworks was the software in this paper

Optimization of the design and manufacture of a solar-wind hybrid street light

Abstract: The demand for electricity has escalated and cannot be fulfilled by conventional energy sources alone. There has been a rising demand to seek new renewable energy sources. Although solar and wind energy are the most cost effective renewable energy sources, they are unreliable due to the sporadic nature of their occurrence, if implemented as standalones. In Zimbabwe, solar street lighting has been implemented since 2014 as a solution to the erratic power supplies and outages. Wind potential in Zimbabwe has been identified at elevated heights, with Gweru having the maximum power density of 115 W/m2 at 50 m hub height. This paper presents the optimization of the design of a hybrid renewable energy system (HRES) of solar and wind energy to power a 160W streetlight. The system consisted of a wind turbine, photovoltaic modules, charge controller, battery bank and lights. The system sizing was done in Excel using wind and solar data obtained from the database, HOMER Software Package and PVSyst. The 3D streetlight was modelled using Inventor Professional and a working prototype was manufactured. The results showed that the HRES reduced the energy storage requirements by 38.75% with an overall cost reduction of 14.4%, relative to a standalone solar streetlight. The diffuser effect to the turbine was experimentally assessed, showing 69.3% increase in turbine power output and a 50% decrease in energy storage requirements. Further research can be carried to improve the reliability for standalone systems

Waste heat and energy recovery system from smelter off-gas for a platinum processing plant

Abstract: Most mineral processing companies are energy intensive especially if smelting is used in extraction. After processing, the energy is correspondingly dissipated as heat and toxic gases, requiring stringent controls for sustainability and safety. In recent years, Southern Africa has grappled with power shortages resulting in the scaling down of company operations. Increases in manufacturing activities demand for more energy but this has evidently outstripped supply due to the depletion of natural resources. Mineral processing industries are probably the worst affected due to fluctuations in world metal prices. These challenges require sustainable production strategies to remain in business. This research was carried out at a platinum processing company in Zimbabwe which uses smelting in extractive metallurgy, consuming millions of dollars in energy but also dissipating this as heat and furnace exhaust gases. The focus of the research was on finding ways to turn these challenges into opportunities by recovering the heat and using it for other purposes. A waste heat and energy recovery system was designed to work in conjunction with the smelters and electrostatic precipitator. The proposed system is expected to increase furnace efficiency by 8.5% with an anticipated output of 1.033 MW and an overall plant efficiency of 22.7%

Data collection and statistical data analysis in preparation for simulation of a furniture manufacturing company

Abstract: Systems that are simulated are generally made up of one or more elements that have some uncertainty associated with them. These systems may eventually evolve in a manner that is not completely predictable and thus become stochastic in nature. Simulation of stochastic systems requires that the variability of the elements in the system be characterized by probability distributions or concepts. An 'As- Is-Analysis' of the plant layout and product process flows was carried out at a furniture manufacturing company. Process data for four of their main products namely, pallets, baby tenders bunk beds and standard coffins was collected using a specially designed data sheet. An analysis of the product flow times was carried out by grouping the data into four time variables namely, material movement, processing and waiting (idle) times before and after processing at the active workstation. The distributions of these variables were obtained using graphical methods in which smooth distribution curves were generated. The gamma distribution with shape parameters of α= 3 and α=2 characterized the baby tenders while the product flow times for pallets were characterized by both the gamma distribution, α=3 and the exponential distribution with the mean varying between 14.95 and 271.78 seconds. All the data and analysis carried out produced useful information for input to the design of experiments for simulation