ВПЛИВ ПАРАМЕТРІВ АДИТИВНОГО ВИРОБНИЦТВА НА ВЛАСТИВОСТІ ВИРОБІВ З ФОТОПОЛІМЕРУ

Purpose. Study of the influence of additive manufacturing parameters and post forming operations on complex mechanical properties of the articles formed from UV curable acrylic oligomer. Methodology. Determination of physical and mechanical properties of standard samples which was formed by additive manufacturing technics from UV curable polymer. Tensile strength and relative elongation at brake according to ISO 527-2:2012, impact strength according to: ISO 179-1:2010. Durometer hardness according to:ISO 2039-1:2001. Bending modulus according to: ISO 178:2010. Density according to: ISO 1183-1:2019Findings. Additive manufacturing parameters for stereolithography process was studied for liquid UV curable acrylic oligomer. Study was focused on influence of forming settings and post forming treatment of complex mechanical properties of final articles which was shaped as standard testing samples. Properties of additive manufactured samples was compared with the properties of samples which was cured by UV light is bulk inside shaped cavity with the same geometrical dimensions. Correct post forming treatment results in up to 2 – 3 times increase in tensile strength. Post forming treatment is necessary for achieving functional level of mechanical properties, comparable to the properties of typical industrial polymers. Study of influence of UV light exposure during additive manufacturing shows double fold increase in tensile strength but reduce overall forming speed. Impact strength increase with increasing exposure time and significantly increase with duration of post forming treatment. Post treatment operations with correct parameters can result in forming articles with level of properties sufficient for functional applications. Originality. Study was focused on mechanical properties of UV curable polymer in dependence from forming parameters of additive manufacturing process and post treatment operations. Application of correct post forming setting can lead to material properties with valuable for functional applications.Practical value Optimal parameters for additive manufacturing process based on UV curable resin and LCD exposure technology was investigated. Forming and post forming parameters significantly influence complex mechanical properties of formed articles.

Complexity-Based Analysis of the Effect of Forming Parameters on the Surface Finish of Workpiece in Single Point Incremental Forming (SPIF)

Nowadays, the manufacturing industry is focused on newer modern manufacturing methods, such as single point incremental forming (SPIF). The popularity of the SPIF process in the manufacturing industry is increasing due to its capability for rapid prototyping, forming complex geometry with simple steps, and customizing products for customers. This study investigates the effect of forming parameters (feed rate and step size) on the surface structure of the aluminum AA6061 sheet. We employ fractal theory to investigate the complexity of deformed surfaces. Accordingly, we study the relationship between the complexity and roughness of the deformed surface. The results show that the complexity and roughness of the deformed surface vary due to the changes in forming parameters. Fractal analysis can be further employed in other manufacturing processes to investigate the relation between the complexity and roughness of processed surfaces.

Regulating the Deformation Properties of Paper by Varying the Degree of Its Anisotropy

Mechanical properties are crucial in assessing the paper quality. Deformation and strength properties of paper are determined by the strength and stiffness of the interfiber and intermolecular hydrogen bonds. The contribution ratio of interfiber and intermolecular hydrogen bonds to the strength of paper can be changed by adjusting the degree of its anisotropy. The article presents the results on a study of the deformation properties of laboratory anisotropic paper samples from kraft bleached softwood pulp with a beating degree of 30 °SR. The samples had basic weight of 90 g/m2 and the degree of stiffness anisotropy TSIMD/CD of 1.75–4.08. They were made by using Techpap SAS automatic dynamic handsheet former (Grenoble, France), with varying forming parameters – diameter of the nozzle, motion speed of the forming wire, and injecting speed of pulp. Deformation properties were determined by tensile test and processing of the stress-strain dependence (σ−ε). The outcomes have shown that, an increase of the fiber orientation degree in paper structure by changing the forming parameters caused a change in the nature of the paper deformation under tension. Increasing the fiber orientation degree in the structure of paper made it possible to increase the strength by 55 %, tensile stiffness by 63 % in the machine direction, while reducing the extensibility by 10 %. In the cross direction, it was possible to decrease tensile stiffness by 33 %, strength by 55 %, and increase the extensibility by 5 %. Anisotropy of tensile strength was 1.73–6.00. The greatest effect was obtained for the elasticity modulus in the pre-failure zone E2 (2.8–38.6). It means that, fiber orientation had a key importance when large deformations in the samples took place. The established quantitative regularities allowed optimizing the values of the deformation and strength properties of paper, and their ratio in the machine direction and cross direction due to the variation of the forming parameters. For citation: Rech D., Potasheva A.N., Kazakov Ya.V. Regulating the Deformation Properties of Paper by Varying the Degree of Its Anisotropy. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 174–184. DOI: 10.37482/0536-1036-2021-5-174-184

Effects of press-forming parameters on the dimensional stability of paperboard trays

The dimensional stability of press-formed paperboard trays was investigated during heating and cooling of trays packed with oatmeal. Female mold tool temperature, dwell time, pressing force, and blank holding force were altered in the press-forming of the trays to observe their impacts on the dimensional stability. Dimensional measurements of the trays showed reduced tray width, and the trays exhibited distortions on the tray flange and outer wall. The results showed smaller effects on the tray length, parallel to the machine direction of the material. Improved dimensional stability of the trays was found with a 180 °C female mold tool temperature, a 600-ms dwell time, a 150-kN pressing force, and a 1.44-kN blank holding force. The optimal press-forming parameters were concluded to enhance bonding of the paperboard fibers during the press-forming. The optimization of the press-forming parameters was found necessary to reduce the observed negative response of the material to the challenging environmental conditions in the production of prepared food.

Effects of Forming Parameters on Fatigue Life in Incremental Sheet Punching

In order to investigate the effects of main forming parameters on the fatigue life in incremental sheet punching, wavelength and amplitude were selected as factors, and fatigue life of truncated pyramids and virgin material was selected as indicator. The effects of the parameters were identified whereby the design of full factorial experiment, fatigue comparative test, analysis of variance, Tukey test, and t-test. It was found that wavelength and amplitude significantly affect the fatigue life. In addition, the improvement of fatigue life decreased with the increment of wavelength and increased with the increment of amplitude when it is less than a certain value, followed by decreasing.