Friction coefficients and surface properties for laser sintered parts

Today different types of established rapid prototyping (RP) systems are available. In a Selective Laser Sintering (SLS)-process a CAD-model is designed and converted into a STL-file (Standard Tessellation Language). Next the body information is sliced into layers and transferred to the production system. By melting the powder-material using a laser beam, parts can be created layer by layer. Afterwards the parts are cleaned and several finishing treatments can be applied. The primarily aim in using RP was to reduce the product development time and to create design models. Nowadays whole assemblies and complex parts can be produced altogether in one manufacturing step with RP-systems. To ensure a save part construction due to calculation formulas and basic material constants, predictable design calculations are necessary. Concerning SLS-materials like polyamide PA 2200 components, only specific mechanical values like the tensile and flexural modulus have been identified. To fill this gap concerning tribological characteristics and to reach the next level of rapid manufacturing the key aspects of this article are the determination of the coefficient of friction μ₀ of SLS-parts made of polyamide PA 2200 concerning several influence factors. An anisotropic material behavior, a decrease of the coefficient of friction μ0 with increasing contact pressure, larger contact areas and more intensive finishing treatment could be detected. Due to the knowledge of the identified material properties, now friction loaded components can be configured and used as functional machine parts.