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Faculty of Engineering and Built Environment

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Author: search.filters.author.Dewa, MendonStart date: 2022

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Now showing 1 - 10 of 18
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    An adaptive neuro-fuzzy inference scheme for defect detection and classification of solar Pv cells
    (Academy Publishing Center, 2024-09-12) Moyo, Ranganai Tawanda; Dewa, Mendon; Romero, Héctor Felipe Mateo; Gómez, Victor Alonso; Aragonés, Jose Ignacio Morales; Hernández-Callejo, Luis
    This research paper presents an innovative approach for defect detection and classification of solar photovoltaic (PV) cells using the adaptive neuro-fuzzy inference system (ANFIS) technique. As solar energy continues to be a vital component of the global renewable energy mix, ensuring the reliability and efficiency of PV systems is paramount. Detecting and classifying defects in PV cells are crucial steps toward ensuring optimal performance and longevity of solar panels. Traditional defect detection and classification methods often face challenges in providing precise and adaptable solutions to this complex problem. In this study the researchers pose an ANFIS-based scheme that combines the strengths of neural networks and fuzzy logic to accurately identify and classify various types of defects in solar PV cells. The adaptive learning mechanism of ANFIS enables the model to continuously adapt to changes in operating conditions ensuring robust and reliable defect detection capabilities. The ANFIS model was developed and implemented using MATLAB and a high predicting accuracy was achieved.
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    Deploying built-in quality to reduce scrap in an automotive component manufacturer
    (SAIIE, 2024-05-31) Dewa, Mendon; Makua, Edward
    Automotive component manufacturers face global competitive challenges, and the paradigm has shifted from product price as the determining factor of competitiveness to the quality of the product. An automotive component manufacturer was struggling to manage the outflow of defects, and adding inspectors as quality gates to the rear-step bumper production line had severe cost implications. This study aimed to reduce the number of defects by deploying a strategic path of implementing built-in quality. Quality tools were used, and the study’s results included significant manpower reduction, improved quality capability, and reduced scrap rates and reworks.
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    Utilizing lean techniques through a P-D-C-A approach to drive built-in-quality in a thermoforming line for an automotive component manufacturer
    (Ponte Academic Journal, 2023-08) Makua, Edward Sontaga; Nleya, Bakhe; Dewa, Mendon
    Automotive component manufacturers are faced with competitive challenges globally. At the heart of these challenges is the need to produce parts that are of high-quality standards. Now more than ever before, organizations need to work as a unit to drive the fundamentals of built in-quality if they are to maintain good quality standards and overall cost competitive leadership. An automotive component manufacturer was struggling with managing the thermoforming line outflow of defects to their customers. Substantial amounts of resources in the form of inspectors were being added on their manufacturing lines to form quality gates and inspect for quality. This has resulted in cost implications and major profitability losses and further expanded their cost of quality. The severity of the problem was further exacerbated by the acceptance of the quality gates as a status quo with little or no initiatives to turn around the situation. The aim of this study was to subdue the traditional quality management approach of inspecting for quality by introducing a series of lean manufacturing techniques that process capability and built-in quality. The study streamlined a sequence of lean manufacturing techniques that supported each other in their findings and results to develop a Plan-Do-Check-Act (PDCA) based strategic approach to drive in-process quality capability in the manufacturer’s Thermoforming line. The results of study were significant manpower reduction on the lines, improved quality capability results, reduced expected scrap rates and reworks, and an overall strategic guideline for the implementation of built-in-quality in automotive component manufacturer’s thermoforming line
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    Implementation of fuzzy logic in scheduling a flexible manufacturing system
    (Southern African Institute for Industrial Engineering, 2023-10-31) Dewa, Mendon
    A flexible manufacturing system (FMS) has the advantage that it can easily adapt to equipment malfunctions and changes in the quantity or type of the product being processed. Proper scheduling is critical for production planning in order to meet customer demand. The case study organisation has been facing challenges in meeting due dates while concurrently minimising lead time and maximising machine utilisation. This paper presents the deployment of fuzzy logic in scheduling a flexible manufacturing system. The proposed approach identifies scheduling parameters for routing parts through system and membership functions and fuzzy rules are constructed to develop the best schedule using a toolbox on a MATLAB fuzzy logic platform. After comparison of several priority rules for job sequencing, the results demonstrated the applicability of fuzzy logic as a decision tool in the scheduling of flexible manufacturing systems.
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    Mixed model line balancing for manual assembly system
    (Southern African Institute for Industrial Engineering, 2023-10-31) Dewa, Mendon
    It is imperative for organisations in the automotive industry to adopt a culture of continuous improvement due to a highly competitive market environment. An automotive manufacturer had adopted a takt time of 60 minutes but has been facing challenges in meeting the daily target of vehicles produced per day. The challenges were attributed to the imbalance of the assembly line and waste generated from non-value adding activities. The focus of this work is to improve a manual automotive assembly system. Time studies were conducted, a list of tools and shovel-ware components was compiled, and work stations were allocated to all the operations. After line balancing, the bus trailer was moved from the sub-assembly bay to the production line leading to more productivity. Additionally, the centralisation of bus trailer allowed for the optimal use of the tools, and the savings that were derived amounted to R350 000 per year.
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    The implementation of an andon production management system to improve the efficiency of tracking of output scores
    (Southern African Institute for Industrial Engineering, 2023-10-31) Dewa, Mendon; Govender, Prenisha
    With the rapid ever changing technological advances, simple processes are easily changed from manual to automated. An automotive company struggled to keep track of their hourly target as well as the shift production scores. This was crucial to the production line management as this posed as a difficulty to determine the line overall efficiency as well as the possible factors of downtime. This paper is aimed to improve the tracking of hourly scores on a moving conveyor using an automated production management Andon system. Using the PDSA cycle, this automated system was implemented which made capturing of scores easier and more efficient. Once implemented, the daily downtime analysis report could be analyzed and factors affecting the production score were further investigated by the production line management. These contributors were then addressed with implemented countermeasures resulting in a high efficiency line as well as correctly tracked hourly scores.
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    Use of kaizen principle and line balancing technique for process improvement in the assembly of automotive components
    (SAJIE, 2022-11-11) Govender, Prenisha; Dewa, Mendon
    Continuous process improvement is critical for organisations to stay in business. An automotive component manufacturer faced productivity challenges after the launch of a new hybrid C-SUV automobile in South Africa. This paper aims to improve the seat cover sewing process line through a line balancing technique. The use of process standard times to balance the production process initially led to bottlenecks, and the cycle time was above the takt time of the assembly line. Through the use of work-study analysis and time studies, the bottleneck processes were identified. Elements were then categorized, and kaizen implementation occurred at the processes. The processes were then rebalanced to meet the calculated cycle time. A root cause analysis was also conducted to investigate the sources of muda and the factors affecting the rate of working. The assembly line was then rebalanced, and the balance delay decreased by 33%.
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    The role of computational intelligence techniques in the advancements of solar photovoltaic systems for sustainable development : a review
    (Arab Academy for Science, Technology, and Maritime Transport (AASTMT), 2022) Moyo, Ranganai Tawanda; Dewa, Mendon
    The use of computational intelligence (CI) in solar photovoltaic (SPV) systems has been on the rise due to the increasing computational power, advancements in power electronics and the availability of data generation tools. CI techniques play an important role in modelling, sizing, forecasting, optimizing, analysing and predicting the performance and control of SPV systems. Thus, CI techniques have become an essential technology as the energy sector seeks to meet the rapidly increasing demand for clean, cheap, and reliable energy. In this context, this review paper aims to investigate the role of CI techniques in the advancements of SPV systems. The study includes the involvement of CI techniques for parameter identification of solar cells, PV system sizing, maximum power point tracking (MPPT), forecasting, fault detection and diagnosis, inverter control and solar tracking of SPV systems. A performance comparison between CI techniques and conventional methods is also carried out to prove the importance of CI in SPV systems. The findings confirmed the superiority of CI techniques over conventional methods for every application studied and it can be concluded that the continuous improvements and involvement of these techniques can revolutionize the SPV industry and significantly increase the adoption of solar energy.
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    Reduction of excessive claim costs associated with damaged cardboard cartons in distribution
    (Southern African Institute for Industrial Engineering, 2022-10-03) Dewa, Mendon; Biyela, Khayelihle
    Courier services suffer a severe problem of experiencing parcel damages that lead to customer complaints and carton claims. Cardboard cartons are easily prone to being damaged during transition and courier companies are not always accountable for parcel damages but still endure consequences as claim costs continue to rise every financial year. The Plan-Do-Check-Action system was used to collect and analyze data intending to prioritize problems, and a parcel inspection was conducted for 22 suppliers to measure variables. Correlation analysis was conducted, and results showed a strong correlation between weight, size, internal carton utilization, and flute corrugated size used on a cardboard. A fish-bone diagram was used to represent the potential root-causes, as a result the relationship between these variables has proven to have the most impact on parcels being damaged. The correlation between the flute corrugated size and internal carton utilization along with mishandling of stock impacted damages the most. During the movement, the durability of the carton is highly depended on these variables. An implementation of training and awareness on how to handle stock with care was conducted to reduce damages during distribution while optimising operations.
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    Process improvement for the manufacture of excavator bucket for a construction equipment manufacturer
    (Southern African Institute for Industrial Engineering, 2022-10-03) Mdletshe, Mfundo; Dewa, Mendon; Hattingh, Teresa
    A construction equipment manufacturer procured the SK220 excavator machine from Japan without the bucket. Given the poor quality of outsourced buckets, the company considered manufacturing its own strong and reliable excavator buckets. However, due to Covid 19 pandemic, the company failed to deliver the buckets on time, which affected committed customer orders. The aim of the paper is to pinpoint the bottlenecks within the supply chain and institute some corrective and preventive actions to improve the manufacture of excavator bucket for the construction equipment manufacturer. Capacity planning was conducted to establish the weekly production capacity for the excavator bucket, considering the number of workers and equipment. Root cause analysis was conducted to pinpoint all the waste that characterised the supply chain and significant counter-measures were implemented. The results demonstrated significant productivity improvement, waste reduction and average in monthly sales amounting to R6 250 000.