Influence of Atmospheric Conditions on Mechanical Properties of Polyamide with Different Content of Recycled Material in Selective Laser Sintering

Abstract

The price of material is an important factor when selecting the additive polymer procedure. In selective laser sintering (SLS), the price can be reduced by the recycling of material, i.e., with different shares of original and recycled material, as well as by the orientation of the product during manufacturing. Numerous tests warn that orientation in the direction of z axis should be as low as possible to reduce the total price of the product. The product also has to satisfy the influence of atmospheric conditions to which it is exposed during its lifetime, i.e., UV radiation and humid environment. UV light, with sun being its most common source, and average humidity in different parts of the world can be approximately from 20% to 90%, depending on time, day and geographic location. In this work, the test specimens have been made of original, mixed and 100% recycled material and then exposed to the influences of UV radiation and water absorption. After having been exposed to atmospheric conditions for a longer time, the mechanical properties of the polyamide products made by selective laser sintering were tested. The results show that exposure to UV radiation reduces tensile elongation at all ratios of recycled material and orientation of 70–90% except in the z direction, while in flexural deformation it is the other way around. The effect of water was observed only between the 7th–14th day of absorption with a decrease in strength until the deformation did not change.

Study of the Mechanical Properties of 3D-Printed Onyx Parts: Investigation on Printing Parameters and Effect of Humidity

“…They reached more than 42% deformation (the limit value for the extensometer used), which is higher than the 20% to 30% deformation of the specimens at the start of aging. These results are consistent with those of previously published works [26][27] . Moisture affects the onyx parts because of the presence of hydrogen in the atomic chain of the ny-lon molecule and the presence of porosity in the parts, which strongly favors moisture absorption.…”

“…Moisture affects the onyx parts because of the presence of hydrogen in the atomic chain of the ny-lon molecule and the presence of porosity in the parts, which strongly favors moisture absorption. Compared with the work of Pilipovic et al [26] , who used a Selective Laser Sintering (SLS) process and a polyamide 12 material, it was found that the impact of moisture on the mechanical properties was less. They discovered that the mechanical properties do not vary after 14 days of exposure; a variation in mechanical properties was observed only after 28 days of exposure.…”

Characterization and Sustainability Potential of Recycling 3D-Printed Nylon Composite Wastes

“…Because of the development of low-cost polymer additive manufacturing, the industry is developing incredibly fast [15,16]. The common processes of 3D-printing technology are fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS) [17,18]. In addition, the technology has taken the lead in manufacturing sustainability by reducing the environmental impact [19][20][21][22].…”