Improving Method in Prediction of Screen Life with DMAIC - in #1 Blast Furnace Case of D company

• Main Authors: LIU, CHUN-LIANG, 劉純良
• Other Authors: CHEN, SHUI-CHUAN
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/4yaga4

碩士 === 國立勤益科技大學 === 工業工程與管理系 === 107 === The raw materials with too small particle size must be sieved to remove in ironmaking process of the Blast Furnace. To prevent too small materials from being caught by the dust collecting equipment during transportation, the screening machine is an important equipment of the process in the Stock House. And it also prevents that kind of materials from being filled with the pores between the raw materials to affect the melting reaction. The screen is an important part of the screening machines. My research on the screening equipment of the Blast Furnace Stock House is based on equipment in one of the steel factories in central Taiwan. It’s a point that screens should be mainly changed at the time of planned maintenance (PM) before the damage occurred. By the customer’s feedback and expectation, it will also reduce unnecessary times of maintenance and save the time of maintenance. Starting from the maintenance quality of the customer’s expectation, discussing the life of the sinter screen and the best time of screen replacement, my research is focused on improving screen replacement with DMAIC. And it is also made reference to equipment maintenance and preventive maintenance theory. With systematic improving strategy and scientific methods (using Seven Basic Tools of Quality, Regression Analysis, Excel, Minitab and other tools) to analyze and solve problems. The goal of the research is to find out the best preventive maintenance, maintenance cycle and maintenance cost by evaluating, predicting the screen life and determining the exact changing time of the screen. According to the results of the research, the producers hope to reduce the times of the suspending work in terms of the impact of production loss caused by suspending work. Therefore, the benefits by controlling the PM schedule are more corresponding to the expected results. By improving the PM schedule, the achievement rate of method A in the PM program is increasing from 61.29% to 84.62%. By replacing four pieces of screen, the achievement rate of the method B is increasing from 83.87% to 88.46%. Both methods A and B achieve the expected performance. Especially using method A produces significant benefits in the improvement of the Failure Costs. My research is contributed to improve the PM schedule, such as replacing the screen before the damage, replacing the whole machine, reducing the times of the suspending work, and improving the estimate of the cost. It also saves NT$ 2.466 million dollars / year (P54). Furthermore, it will reduce NT$ 11.446 million dollars of maintenance cost with method A by non-planned suspending work (P58).