Date of Award


Degree Name

Master of Science




Jianmei Zhang


This Thesis analyze the plastic injection molding parameters in order to identify which parameters significantly affects the flow properties of Polibuthylen Thereptalate with 45% glass/mineral reinforcement, and which levels are the best to use for those parameters. With the purpose of optimizing the plastic flow conditions in an injection mold to obtain parts free from short shots (term used to describe a plastic part that is incomplete due to the poor plastic flow in the mold runners and cavities).

The used approach is Taguchi design of experiments to define which parameters have significant effect on the response variable, and the best parameter levels to use. The parameters to use in the study were chosen from molding process literature and, previous experiences with other past experiments.

Due to the necessity of representing the results with a common way for the industry, a Process Capability Index (CPK) are calculated for every run of the experiment in order to perform a comparative analysis and investigate if the Taguchi's results correlates with the CPK approaches. The CPK approach give a better understanding of the results due to CPK is an index that takes into account the mean and the deviation at the same time, also is more common for the industry to take decisions.

Finally, simulations of the process with mold flow software are performed to predict the plastic flow behavior. Results from mold flow analysis, Taguchi's design of experiments and CPK approaches are compare to establish if mold flow software can be effectively be used to predict results from a plastic injection process. This last approach can lead to time, components, materials for cost savings. Normally it is very expensive to conduct experiments.




Received from ProQuest

File Size

51 pages

File Format


Rights Holder

Israel Sanchez