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Senior Project: Using Design of Experiment (DOE) to Identify Material and Processing Variables that Impact Part Warpage in Injection Molding

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2012 ASEE Annual Conference & Exposition


San Antonio, Texas

Publication Date

June 10, 2012

Start Date

June 10, 2012

End Date

June 13, 2012



Conference Session

Sustainable Product Development and Manufacturing

Tagged Division


Page Count


Page Numbers

25.1154.1 - 25.1154.13



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Paper Authors


Rex C. Kanu Ball State University

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Rex C. Kanu is Coordinator of the Manufacturing Engineering Technology program.

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Tyler Steven Steward Ball State University

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Tyler S. Steward is a Manufacturing Engineer at Exedy of America Corporation. Address: 6025J Grace Lane Knoxville, TN 37919. Phone: 765-366-9686. Email:

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Using Design of Experiment (DOE) to Identify Material and Processing Variables that Impact Part Warpage in Injection MoldingThe injection molding of plastics parts consists of a series of events that include mold closing,injection of molten plastics into closed mold, cooling of molten plastics, mold opening, andejecting of molded parts. Of these events, the cooling process comprise 75% of the injectionmolding cycle time. Consequently, identifying the material and processing variables and/or theirinteractions that significantly influence the cooling process is of utmost importance inunderstanding and optimizing the cooling process and in preventing part warpage. Many studieshave investigated different aspects of the cooling process in injection molding, but none haveincorporated the thermal diffusivity of the material in their studies. Thermal diffusivity measurehow fast thermal energy travels through materials and thus affects the rate of thermal energy(heat transfer) removal during the cooling process. It appears the thermal diffusivity of plasticsmay play a crucial in the cooling process given that ratio of the thermal diffusivities of thematerials generally involved in the cooling process, plastics, coolant (water), and steel is 1:1.6:50(plastics:water:steel). This implies that thermal diffusivity of plastics may be the controlling orlimiting variable in the cooling process. Therefore in this study, by using the design ofexperiment (DOE), it is expected that the roles processing variables play in cooling process andin plastics part warpage. These variables include plastics thermal diffusivity, coolant flowregimes, mold temperature, and injection back pressure.This study is an attempt to help students in a manufacturing engineering technology programintegrate concepts taught in the design of experiment and plastics courses in trying to understandand solve an industrial problem in injection molding. The success of this approach will be sharewith the audience.

Kanu, R. C., & Steward, T. S. (2012, June), Senior Project: Using Design of Experiment (DOE) to Identify Material and Processing Variables that Impact Part Warpage in Injection Molding Paper presented at 2012 ASEE Annual Conference & Exposition, San Antonio, Texas. 10.18260/1-2--21911

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