Computer aided design of extrusion blown film die

• Main Authors: Luo,Dah-Woei, 羅大偉
• Other Authors: Wu,Jiann-Shing
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/23832717614982963083

碩士 === 國立交通大學 === 應用化學研究所 === 85 === The blown film die , which is also called the spiral mandrel die , is widely used in the production of tubular products , such as pipes , plastic bags and so on . In order to produce the beautiful and durable products , helicalgrooves cut on the mandrel surface are designed to increase flow uniformity and eliminate welding lines . They are the main characteristics of the spiral mandrel die . There are six parameters in designing the spiral mandrel die , which are the diameter of the mandrel , the number of the helical groove , the initial width of the helical groove , the initial depth of the helical groove , the helical angle and the gap , respectively . This study analyzed the isothermal-non-Newtonian flow , based on the two-dimensional flow simulation , in a die with a mandrel of 11 cm diameter and four helical grooves . Then , the Taguchi method was used to determine the optimal values of the rest of four parameters by considering the performance of the die . The performance of the die was examined from flow uniformity , degree of mixing and total pressure drop . Finally , the optimal geometry of the die was determined . Sequentially , the performance of the die was examined under the nonisothermal condition and the discrepancy between the isothermal and the nonisothermal condition was compared . The results show that it is enough to determine the elementary shape of the die according to the isothermal assumption .