3RD INTERNATIONAL CONGRESS ON TECHNOLOGY - ENGINEERING & SCIENCE - Kuala Lumpur - Malaysia (2017-02-09)

A Study On The Metal-plastic Bond Strength In A Metal Insert Molding Process
Various methods can impart a metallic appearance to plastics, including painting, coating, and injection molding using pearl resin, but the most effective method is to cover plastic parts with a processed metal sheet. However, an additional process for attaching the metal onto the plastic increases both the production time and the rate of defects, thereby reducing productivity and product competitiveness. Using a metal insert molding process, wherein a processed metal part is first inserted into a mold and then plastic is injection molded on the metal part, the metal and plastic can be attached to each other without using adhesives or additional processes. However, in conventional insert molding, wherein the two adhering materials simply come face to face, the two materials are easily detached due to differences in their material characteristics or shrinkage percentages. The most dominant stress that separates the metal from the plastic is shear stress, which occurs longitudinally. To evaluate the maximum adhesive stress in the adhesion between the metal and plastic, the shape of the specimen in this study was selected to conduct a bond strength test. The metal specimens in insert molding were prepared using various surface treatments, including engraving and embossing, to evaluate the bond strength between the metal and plastic under various surface morphology. In order to measure the bond strength, a tensile tester applied a lengthwise shear stress to the adhesion part until the part separated into two pieces, which indicates the maximum shear stress. As a result, the embossed surface providing undercut shape showed a higher bond strength between the metal and plastic than the engraved surface.
Se Lyn Kim, Si Tae Won, Min-Young Lyu, Sang Hoon Lee, Sung Woong Jang, Jin Soo Jeong