Effect of Femtosecond-Laser-Structured Injection Molding Tool on Mechanical Properties of the Manufactured Product

Abstract

During the injection molding process, the melt travels with a flow due to friction. As the velocity of the layers next to the wall is less than that of those flowing in the middle of the channel, a fountain flow is formed at the melt front. The temperature of the polymer surface decreases from the melt temperature to the contact temperature after contacting the mold surface. Based on all this, a complex shell–core structure is formed in injection-molded products, which can be influenced by the processing parameters and the surface of the tool insert. This paper focuses on investigating the effect of the microstructures replicated from the insert to the polymer product on its mechanical properties. During the research, two microstructured surfaces were created, with different effects on the melt flow formed by the femtosecond laser. These were compared with a ground insert to analyze the effects. For examining the effect of technological variables on the mechanical properties, an experimental design was used. The structure created by the femtosecond laser on the surface of the tool influenced the mechanical properties of the polymer products. Recognizing the effect of microstructures on the melt front and, through this, the change in mechanical properties, a predefined polymer product property can be achieved.

Investigation of the Tensile Strength of Adhesive-Bonded Steels Using Surface Treatments

“…Another theory is the mechanical theory [16], according to which the surface to be bonded is never completely flat, so there are many peaks and valleys on the surface [17]. At one time, it was pseudo-suggested that adhesion was only created by the adhesive flowing into these voids, filling the microcavities, and when it made contact, the adhesive mechanically held the two bonded surfaces together.…”