Mohd Nazir Bin Mat Nawi creator author. text my 2025 2025 monographic eng xix, 155 pages : illustrations ; 30 cm. + 1 CD-ROM Achieving efficient paint removal without damaging the surface is one of the primary areas of focus for paint removal operations in paint restoration. Traditional cleaning techniques, such as chemical and mechanical cleaning, are widely used to remove paint because they are convenient and affordable. However, these methods pose environmental risks and substrate damage, which may limit their future use. As a result, waterjet technology, an eco-friendly and non-traditional technique, has gained traction in the industry for its effectiveness and minimal impact on substrates. Research on waterjet cleaning input parameters mainly focuses on pressure, traverse rate, and standoff distance. The present study attempts to investigate the effect of new parameters, namely the number of cleaning passes and overlap rate during waterjet cleaning of the mild steel painted surface. Also, the impact of other typical parameters, such as hydraulic pressure and abrasive mass flow rate, was further analyzed using Response Surface Methodology (RSM). The quality of cleaned surfaces was investigated regarding surface roughness, topography, microstructure, material removal rate, and cleaning efficiency. Empirical models were developed to predict surface roughness, cleaning efficiency, and Material Removal Rate (MRR), with ANOVA confirming their consistency. These models showed strong correlations between measured and anticipated responses, with desirability functions providing optimal parameters, resulting in reliable surface roughness, cleaning rate, and MRR predictions. It became evident that neither the number of passes nor the overlap rate resulted as the primary parameters in optimizing the paint cleaning efficiency from the analysis of variance (ANOVA) and Pareto chart. The analysis of RSM identified that the optimal parameters for effective cleaning with minimal surface damage using abrasive waterjet cleaning are a pressure of 62 MPa, a single pass, and a 25% overlap rate with surface roughness of 3.557 μm, MRR of 0.189613 g/min and cleaning efficiency of 25 %. It was also observed that increasing the number of passes and overlap rate yielded only a slight decrease in surface roughness. This highlighted the complexity of the waterjet cleaning process in determining the efficacy of paint removal operation. This underscores the necessity for a comprehensive study of various parameters and their interactions to enhance the efficiency of the paint removal process for practical application which can be applied in improving process design and reducing cost. Keywords: paint removal, overlap rate, waterjet, surface roughness, surface topography, cleaning efficiency, microstructure. specialized Mohd Nazir Bin Mat Nawi Faculty of Manufacturing & Mechatronics Engineering Technology Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang - 2025 Includes bibliographical references Faculty of Manufacturing & Mechatronics Engineering Technology Dissertations Universities and colleges Dissertations Theses Dissertations THE0010342 (Local) UMPSA 260216 20260216184909.0 eng