The mass application of FDM technology is slowed down due to the difficulty of selecting 3D printing parameters in order to manufacture an article with the required characteristics. This paper reports a study into the impact of 3D printing parameters (temperature, print speed, layer height) on mechanical parameters (strength, elasticity module), as well as on the accuracy of printing and roughness of the surface of a specimen based on thermoplastic (PLA plastic). Several batches of specimens were fabricated for this study in accordance with ASTM D638 and ASTM D695, which were tested for tension, geometric accuracy, and roughness. Based on the experimental data, regression analysis was carried out and the functional dependences of the strength, elasticity module, printing precision, roughness of a surface on 3D printing parameters (temperature, speed, thickness of the layer) were constructed. In addition, the derived mathematical model underlying a method of non-linear programming has established such printing parameters that could provide for the required properties of a structure. The analytical dependences reported in the current work demonstrate a high enough determination factor in the examined range of parameters. Using functional dependences during the design phase makes it possible to assess the feasibility of its manufacture with the required properties, reduce the time to work out the process of printing it, and give recommendations on the technological parameters of 3D printing. The recommendations from this study could be used to make PLA-plastic articles for various purposes with the required properties

Tekhnicheskaya Diagnostika i Nerazrushayushchiy Kontrol, 2018, №04. TEKHNICHESKAYA DIAGNOSTIKA I NERAZRUSHAYUSHCHIY KONTROL Quarterly scientific-technical and production journal. ISSN: 0235-3474. Established in 1989. Subscription index: 74475. State Registration Certificate KV 4787 of 09.01.2001. All rights reserved Publisher: B.E.Paton Electric Welding Institute, National Academy of Sciences of Ukraine. Main topics of the magazine: theoretical and practical articles on technical diagnosing and non-destructive testing; flaw detection, residual life of structures. Each issue features: scientific articles; manufacturing experiences; reviews; exhibitions, conferences; advertisements.

Municipal solid waste incineration fly ash (MSWI FA) is a hazardous waste that must be kept in special landfills due to the high amounts of chlorides, sulfates, and heavy metals. The granulation of MSWI FA could be used as a solidification/stabilization (S/S) of fly ash to immobilize hazardous chemical elements and to reduce dust emissions. In this work for granulation, three different binders were used: calcium aluminate cement (CAC), geopolymer (GEO), and Portland cement (PC). Chemical (XRF), mineral (XRD), granulometric compositions, and leaching of prepared granules are presented in the article. Furthermore, the impact of different binders on bulk density, compressive strength, and granule structure was analyzed. The results show that the granules with CAC binder have the best initial compressive strength (about 10 MPa), but these granules were destroyed after the leaching test or connection with water. The geopolymer as a binder did not provide the required compressive strength and immobilization of harmful elements. Granules with a Portland cement binder have a suitable compressive strength, a slight leaching of chemical elements, and good durability in the alkaline and acidic environment; they are also resistant to freezing and thawing cycles.