Investigation of Revolute Joint Clearances Created by an In-Mold Assembly Process

TitleInvestigation of Revolute Joint Clearances Created by an In-Mold Assembly Process
Publication TypeConference Papers
Year of Publication2007
AuthorsAnanthanarayanan A, Thamire C, Gupta SK
Date Published2007/07//
Keywordsacrylonitrile butadiene styrene insert, aluminum mold, assembling, couplings, cycle time reduction, heat transfer, injection moulding, inmold assembly process, mold deformation, molding process, moulding equipment, part count reduction, plastics industry, revolute joint clearances

Revolute joints are frequently used in articulated structures. Traditionally, such a joint is formed by assembling two components. As an alternative, revolute joints can be created inside the mold using an in-mold assembly process. This process eliminates the need for post-molding assembly, thus significantly reducing the cycle time and part count. The functional performance of a revolute joint depends on the clearance in the joint. The clearance in turn depends on the part shrinkage and the mold deformation during the molding process. The presence of a polymer part during the second molding stage makes an in-mold assembly process significantly different from the traditional molding process due to the difference in heat transfer and deformation characteristics. This paper presents experimental data and a preliminary model to explain the differences in clearance produced by an aluminum mold and an Aluminum mold with an Acrylonitrile butadiene styrene (ABS) insert. Our data indicates that there is a significant difference between the clearances observed from these two different types of molds. We believe that clearances produced depend strongly on the thermal history of the parts.