Effect of Strain Rates and Heat Exposure on Polyamide (PA12) Processed via Selective Laser Sintering

Abstract

The use of polymers in the transportation industry represents a great opportunity to meet the growing demand for lightweight structures and to reduce polluting emissions. In this context, additive manufacturing represents a very effective fabrication route for mechanical components with sophisticated geometry that cannot be pursued by conventional methods. However, understanding the mechanical properties of 3D-printed polymers plays a crucial role in the performance and durability of polymer-based products. Polyamide is a commonly used material in 3D printing because of its excellent mechanical properties. However, the layer-by-layer deposition process and ensuing auxiliary steps (e.g., post-processing heating) may affect the microstructure and mechanical properties of 3D-printed nylon with respect to the bulk counterpart. In this work, we explore the effect of displacement rate and heat exposure on the mechanical properties of 3D-printed polyamide (PA12) specimens obtained by selective laser sintering (SLS). Moreover, the thermal characteristics of the powders and sintered material were evaluated using differential scanning calorimetry (DSC). Our results highlight the expected rate dependency of mechanical properties and show that a post-processing heat treatment partly affects mechanical behavior.

An experimental and theoretical investigation on the hyper-viscoelasticity of polyamide 12 produced by selective laser sintering

“…Moreover, all details of the responses are rate dependent i.e., the material is more ductile, larger strains are achieved, and wider hysteresis appear in the cyclic response at a lower loading speed. These results are consistent with formerly reported findings [ 36 , 37 ] and indicate that the viscous nature of the polymer is dominant in such conditions; thus, hyper-viscoelasticity governs the mechanical behaviors of selectively laser sintered polyamide 12. Similar responses with these details are obtained for different maximum loads beyond the elastic limit of the material and also for the produced pantographic structure, as is seen in Fig 6 .…”

Additive Manufactured Parts Produced Using Selective Laser Sintering Technology: Comparison between Porosity of Pure and Blended Polymers

“…Polyamide is the most popular polymer in the SLS application since it allows for the creation of parts that have good mechanical properties, good finishes, low costs, and recyclability [27]. In addition, they are also suitable for the production of composite materials and medical applications [28,29].…”