The Improvement Strategies of Unstable Processing for Hybrid Injection Unit

• Main Authors: Way-min Wu, 吳衛民
• Other Authors: S.Y.Lin
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/arqkzy

碩士 === 國立虎尾科技大學 === 機械與機電工程研究所 === 95 === ABSTRACT Hybrid injection molding machine is usually used to produce high accuracy component with injection speed above 500mm/sec. Production deficiency and product weight instability were frequently occurred during the production process due to the injection unit shack or vibration. This phenomenon is caused by three main factors of mechanism structure inertia in injection unit, backpressure hydraulic relief system of screw and hold pressure parameter adjustment after practical production verifications. This research redesigns the injection structure of injection unit, by moving fixed point of Electric Screw Drive structure backward for injection structure, removing one moving plate, shortening the length of 4 guide tie bars and minimizing moving space of cylinder. The weight of injection unit is thus reduced. Furthermore, screw backpressure hydraulic system is also redesigned. Hydraulic interferences due to injection relief portion being on same injection manifold block were always encountered in original design system. New design is to make injection relief portion individually and led hydraulic oil back to oil tank. In addition, hold pressure adjustment, SOP, is revised as well, which refers to hold pressure P command and actual pressure in order to adjust PID values of the controller so that the setting and actual hold pressure values can match mutually. Finally, by applying Statistical Production Management and Analysis as evaluation tool for tracing production analysis and the hydraulic oil results will be listed and discussed. Three different trials with specific improving strategies are designed to analyze and compare with before-and-after results. The instable rate of the product weight has decreased from 1% down to 0.4%. Stable hold pressure curve, injection end position and minimum injection position are also acquired. The minimizing mechanical inertia can eliminate production noise pollution and the lightening injection structure can increase injection speed up to 700mm/sec. The results of this research have been made it commercialized and adopted on production line immediately in order to gain more market profitable and competition.