Date

2015

Document Type

Dissertation

Degree

Doctor of Philosophy

Department

Mechanical Engineering

First Adviser

Coulter, John P.

Other advisers/committee members

Ochs, John B.; Pearson, Raymond A.; Watkins, Todd

Abstract

The melt modulation concept was originally introduced to control the melt flow during the filling phase of cold runner injection molding machines. Since its inception, several melt modulation systems have been developed. Although previously designed systems successful balanced multi-cavity and family molding parts and controlled weld-line position, they were not commercially viable. The main objective of this dissertation was to employ scientific and business based approaches to develop and enhance a melt modulation technology for cold-runner based injection molding. This research intends to bridge the gap between an important scientific discovery and its industrial applications. This was achieved with the goal of advancing science and technology to enhance polymer product manufacturing. As a result, a modular melt modulation system was developed to deliver intelligent manufacturing and precision control to cold runner injection molding machines. This modular system has the ability to adaptively manipulate injection molding part qualities and control the melt flow and packing processing parameters during each injection cycle. This precision control is cost effective and results in enhanced production rate, less waste, less processing and set-up time, and better product quality. Also, it has been tested to show that controlling packing parameters contributes to enhancing the final product quality. This research also focused on manipulating and controlling packing parameters using melt modulation in order to produce molded parts with different optical and physical properties in each injection molding cycle. Numerical simulations and experimental results of common thermoplastic transparent polymers, such as Plexiglas® V920 (PMMA), LEXAN 101-111 (PC), and STYRON® 685D (GPPS) are demonstrated herein. The work outlined in this dissertation highlights my contributions to the advancement of the science and technology related to multi-cavity injection molding processes as well as the injection molding industry. These contributions included the design and development of a modular melt modulation system to precisely control mold filling and packing pressure and time at the individual cavity level in real-time; and the validation of the impact of packing processing parameters on the quality of injection molding transparent products through numerical simulations and experiments.

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