Rheological Properties of Polyamide PA 2200 in SLS Technology

Mechanical properties, accuracy and tribological properties of additively manufactured models depend on the technological parameters. In the presented work, models made in selective laser sintering technology with modified technological parameters were analyzed.Therefore, the presented research attempts to determine the influence of two technological parameters (layer thickness in the 0.1 - 0.4 mm range and the printing direction (0° and 90°)) on stress relaxation determined during the uniaxial compression test (testing machine-Inspekt 3 kN) and on the mass of models (density of model material) manufactured by SLS technology with PA 2200 polyamide powder. Using the Origin software and the five-parameter rheological model of the so-called "Maxwell-Wiechert model", the rheological models of the samples were approximated, which allowed for the assessment of the possibility of adapting this rheological model for further investigations of additively produced models using SLS technology. The test results showed a clear effect of the layer thickness, both on the stress relaxation and on the mass of the produced models. In addition, it has been shown that the printing direction affects stress relaxation, however, it has no direct effect on the mass (density of the material) of the models. The variant PD = 0° is the most favourable for enabling the production of models with the highest strength, and for the production of reduced weight models

Rheological Properties of Cellular Structures Manufactured by Additive PJM Technology

Intensive development of manufacturing technologies, in particular additive technologies, resulted in new possibilities of making cellular structure models. In this paper the cellular structure samples made of polymer resins in the PolyJet Matrix additive technology were investigated. Relaxation tests according to ISO 3384 were carried out. The influence of geometric structure shape on rheological properties was determined and the most favourable geometric variants of cellular structure models were determined. Using Mathematica and Origin software, a statistical analysis of test results was carried out, along with the determination of five-parameter functions approximating the relaxation curves. The rheological model was adopted and its parameters were determined

Dimensional and Shape Accuracy of Foundry Patterns Fabricated Through Photo-Curing

This paper deals with the potential use of the PolyJet Matrix (PJM) technology and digital materials to fabricate foundry patterns. The primary purpose of the study was to assess the dimensional and shape accuracy of additively manufactured objects by determining the draft angle as well as the roundness, waviness and roughness parameters. The experiments were conducted for cylindrical samples printed using VeroWhite liquid polymer resin. The analysis focused on the relationship between the build direction and the geometry and surface finish of prints. Three different orientations, i.e. 0º, 45º and 90º, were considered. The surface texture analysis involved comparing the statistical, graphical and numerical data, including calculation results obtained with the wavelet transform method. The findings confirm that the build direction has a significant effect on the dimensional and shape accuracy of prints and that the PJM technology can be used to fabricate precise foundry patterns, especially in investment (lost-wax) casting

Quality of surface texture and mechanical properties of PLA and PA-based material reinforced with carbon fibers manufactured by FDM and CFF 3D printing technologies.

The paper presents the results of mechanical tests of models manufactured with two 3D printing technologies, FDM and CFF. Both technologies use PLA or PA-based materials reinforced with carbon fibers. The work includes both uniaxial tensile tests of the tested materials and metrological measurements of surfaces produced with two 3D printing technologies. The test results showed a significant influence of the type of technology on the strength of the models built and on the quality of the technological surface layer. After the analysis of the parameters of the primary profile, roughness and waviness, it can be clearly stated that the quality of the technological surface layer is much better for the models made with the CFF technology compared to the FDM technology. Furthermore, the tensile strength of the models manufactured of carbon fiber-enriched material is much higher for samples made with CFF technology compared to FDM

Tribological Properties of Medical Material (MED610) Used in 3D Printing PJM Technology

The development of modern manufacturing technologies related to the ongoing industrial revolution Industry 4.0, is largely related to the dynamic development of materials chemistry. This means that currently 3D printing technologies allow the production of physical models using newer materials with better properties and application in new industrial sectors. The article presents the results of tribological tests of the bio-medical material under the trade name MED610, which shows biocompatibility for medical and dental purposes. The paper presents the results of measurements of tribological models of samples designed and manufactured in the shape of rings. Using the variable friction parameters, the wear process was described in the pressure-rotational speed (P-V) system. Moreover, the friction coefficient and wear measured by using the linear method were analyzed. The paper also presents a metrological analysis carried out with the application of an optical profilometer on the surface of the samples after pressing at the contact point of the surface during the test. The preliminary review of the test results showed that the MED610 material exhibited relatively good abrasion resistance. However, it cannot be employed for heavily loaded friction nodes, and in the PV diagram even at a relatively small value, the sample models were destroyed

Quality of surface texture and mechanical properties of PLA and PA-based material reinforced with carbon fibers manufactured by FDM and CFF 3D printing technologies

The paper presents the results of mechanical tests of models manufactured with two 3D printing technologies, FDM and CFF. Both technologies use PLA or PA-based materials reinforced with carbon fibers. The work includes both uniaxial tensile tests of the tested materials and metrological measurements of surfaces produced with two 3D printing technologies. The test results showed a significant influence of the type of technology on the strength of the models built and on the quality of the technological surface layer. After the analysis of the parameters of the primary profile, roughness and waviness, it can be clearly stated that the quality of the technological surface layer is much better for the models made with the CFF technology compared to the FDM technology. Furthermore, the tensile strength of the models manufactured of carbon fiber-enriched material is much higher for samples made with CFF technology compared to FDM.Web of Science1311art. no. 167

Analysis of Metrological Quality and Mechanical Properties of Models Manufactured with Photo-Curing PolyJet Matrix Technology for Medical Applications

This paper presents the metrological quality and mechanical properties of models in the form of hook holders manufactured from MED610 polymer material using PolyJet Matrix (PJM) technology. Measurements in the dimensional and shape analysis were made using the optical method with a microscope. The mechanical test was estimated by static tensile testing of the fabricated parts. A comprehensive approach to both the analysis of test results based on standardized samples and real hook models makes the presented results of great scientific and engineering value and creates the possibility of practical use in the medical industry, which has not been so comprehensively presented in the currently published research papers. Analyzing the results of measurements of the geometrical characteristics of the elements, it can be concluded that the PolyJet Matrix 3D printing technology has demonstrated a high level of precision in manufacturing the prototype parts. The static tensile test of samples, taking into account the printing directions, showed a high anisotropy of mechanical properties. The results of both strength and simulation tests indicate that it is necessary to assume a relatively high safety factor, the value of which depends on the direction of printing, which, in the case of such a responsible medical application, is very important

Evaluation of the rheological properties of photopolymers used in Polymer Jetting technology

The paper presents the results of tests related to relaxation of stresses in models of samples made using the technology of photo-curing of liquid polymer resins polyjet modeling (PJM). The models of the samples were made using two types of materials: VeroWhite and FullCure 720. The tests were performed on samples in compliance with the PN-EN ISO 3384 standard. The technological parameter whose impact was analyzed was the orientation of the models on the virtual building platform, which was defined with three variability levels (0°, 45°, and 90°). The tests demonstrated that the position of the models on the building platform has a significant impact on the relaxation of compressive stresses. Moreover, the most advantageous positions of the models on the building platform from the standpoint of relaxation of stresses were determined

The Influence of Printing Orientation on Surface Texture Parameters in Powder Bed Fusion Technology with 316L Steel

Laser technologies for fast prototyping using metal powder-based materials allow for faster production of prototype constructions actually used in the tooling industry. This paper presents the results of measurements on the surface texture of flat samples and the surface texture of a prototype of a reduced-mass lathe chuck, made with the additive technology—powder bed fusion. The paper presents an analysis of the impact of samples’ orientation on the building platform on the surface geometrical texture parameters (two-dimensional roughness profile parameters (Ra, Rz, Rv, and so on) and spatial parameters (Sa, Sz, and so on). The research results showed that the printing orientation has a very large impact on the quality of the surface texture and that it is possible to set digital models on the building platform (parallel—0° to the building platform plane), allowing for manufacturing models with low roughness parameters. This investigation is especially important for the design and 3D printing of microelectromechanical systems (MEMS) models, where surface texture quality and printable resolution are still a large problem

Evaluation of the rheological properties of photopolymers used in Polymer Jetting technology

The paper presents the results of tests related to relaxation of stresses in models of samples made using the technology of photo-curing of liquid polymer resins polyjet modeling (PJM). The models of the samples were made using two types of materials: VeroWhite and FullCure 720. The tests were performed on samples in compliance with the PN-EN ISO 3384 standard. The technological parameter whose impact was analyzed was the orientation of the models on the virtual building platform, which was defined with three variability levels (0°, 45°, and 90°). The tests demonstrated that the position of the models on the building platform has a significant impact on the relaxation of compressive stresses. Moreover, the most advantageous positions of the models on the building platform from the standpoint of relaxation of stresses were determined