Optimization of process parameters for spiral making process / Syahrul Ramadhan Ahmad Kamal Ariffin

Faculty of Mechanical and Automotive Engineering Technology

Thesis (Master of Science) -- Universiti Malaysia Pahang – 2021

Includes bibliographical references

The quality of paper produced by paper machine is very much depends on permeability of dryer fabrics. For that reason, surface profile of the dryer fabrics should be consistent. To achieve this consistency, the spiral used to produce the dryer fabrics must follow stringent specifications in terms of nominal size and tolerance. However, with six independent process variables, the formation of spiral size during spiral making process is not as easy task as expected and may lead to inconsistency. This research focus on investigating and understanding the spiral making process in a more systematic method. The objectives of this research are to evaluate interactions between dependent process variables and independent process variable as well as interactions among independent variables, to determine the most dominant parameters that affect the formation of spiral making process and to optimize and validate process parameters setting for accurate and precise process control. To accomplish these objectives, Analysis of Variance (ANOVA) and Regression Analysis (RA) are conducted using Minitab19 statistical software. The experimental design strategy is conducted systematically based on Box-Behnken method. Six independent variables or process parameters are identified in the spiral making process. One variable is fixed throughout the whole experiment, the variable is speed, and the speed value is set at 1600 rpm. This is to comply to the maximum production output. The independent variables that are manipulated for this experiment are tension, temperature 1, temperature 2, gap 1 and gap 2. Each independent variable has three levels. Based on these information, 46 experimental runs have been configured by Box-Behnken method for data collection of independent variables effects on dependent variables. The dependent variables or responses are spiral width dimension and spiral height dimension. The machine and material used for data collection is Leo horizontal winding machine and man-made polyester, respectively. Initial and final analysis of variance and regression analysis were performed. The initial analysis was performed to identify insignificant variations for elimination prior to final analysis. Final analysis then was performed to obtain better regression model. Based on the analysis of variance and regression analysis, it was found that the strong linear relationship exists between independent variables and dependent variables. Four process parameters; tension, temperature 2, gap 1 and gap 2, were found to affect spiral width dimension. Gap 2 was found to be the only process parameter to affect spiral height dimension. From the analysis, it was also found the most dominant parameter contributes to spiral width dimension is tension. The contribution is 56.71%. As for spiral height dimension, the most dominant parameter is gap 2 with 91.62%. By using the improved regression model acquired by the final analysis, process optimization was performed. The optimized parameters for good dimensional size of spiral are 32.78% for tension, 114°C for temperature 1, 118°C for temperature 2, 4.25 mm for gap 1 and 4.1086 mm for gap 2. This result is validated experimentally. The data were re-collected and re-analyzed. This confirmation test leads to improvement of process capability indices Cpk and Cpm of spiral width dimension and spiral height dimension. For spiral width dimension, the Cpk and Cpm values are 2.23 and 1.91 respectively. For spiral height dimension, Cpk and Cpm values are 3.87 and 3.02. These values show the optimized process parameters capable to produce spiral dimension close to the specification requirement