Funktionsytor : Utvärdering av ytstrukturers påverkan på friktion och stick-slip hos formsprutade komponenter

Sammanfattning

This study investigates how different surface textures affect the frictional behavior between injection molded components, with a focus on achieving low friction and reducing stick-slip. The work was carried out in collaboration with MGS Anderstorp and was based on two industry-related medtech projects where functional surfaces were required to improve the mechanical performance of the components. The study included both traditional VDI surfaces and laser-textured surface structures applied to injection molded test plates manufactured in the materials PP (PMS 272C) and PBT (Celanex 2401 MT and Celanex 2414). The surfaces were analyzed using digital optical measurements, and tribological tests were performed to evaluate friction and stick-slip between different combinations of surface textures. The results show that the combination of the coarse VDI 42 surface and the laser-textured surface L4 produced the lowest friction of all the tested combinations between PP and PBT, while also providing a highly stable friction profile. The study further demonstrates that finer or polished surfaces do not necessarily result in lower friction. Instead, the results indicate that a larger real contact area can increase adhesive friction and thereby contribute to higher friction forces and more pronounced stick-slip behavior. The analysis shows that both the geometry of the surface textures and the material properties have a significant influence on the tribological behavior between plastic components. The combination of a coarse VDI surface and a finer laser-textured surface is considered to create a favorable balance between reduced contact area and stable sliding behavior. The study further demonstrates that laser texturing has significant potential for the development of functional surfaces in injection molding applications. At the same time, limitations in the optical measurement method were identified, which affected the possibility of conducting a complete Design of Experiments analysis. Future research is therefore recommended regarding alternative measurement methods, long-term wear behavior, and optimization of laser-textured surfaces for specific tribological applications.