Additively manufactured complex lattice geometries incorporated in structural materials is a relatively new concept and gaining popularity. In this approach solid bodies are replaced by repeating tailored design cellular structures enabling significantly light-weighted components. However, as a building block of the entire part, these cellular structures' design has crucial role on the overall mechanical properties. The purpose of this work is to reveal how different design parameters (3 different cell types representative of stiff, just stiff and under stiff cases, and cell size) affect the modulus of elasticity and the maximum stress of the compression test samples additively manufactured in cellular fashion. A comprehensive methodology is presented for the design, fabrication , and prediction of mechanical properties of polymer-based lattice structures. A commercial material jetting based 3D printer (i.e., the Objet 30 Prime by Stratasys) was used to manufacture the rigid translucent photosensitive polymer samples with porosity ranging from 54 to 70% and different unit cell structures. Uniquely designed or existing unit cells were used to obtain stretch and bending dominated mechanical behaviors. The failure mechanisms and the performance of the custom design unit cell specimens are investigated via numerical simulation and compression tests. The elastic modulus of cellular structures was calculated and compared using both Gibson-Ashby and Hooke equations. The effect of the unit cell structure and size on mechanical properties is discussed. The results show that while stretch dominated diagonal model shows better strength properties (up to 250%), bending dominated centered model has better elongation (up to 120%). As a general conclusion, it is seen that mechanical properties are enhanced with downsizing of the cell scales. Fine tuning of the unit cells gives a new perspective on tailored lattice structures, enabling structures with stiff or rubber-like behavior to be obtained using the same material.

In this paper, batch reactor design is described. Suspension polymerization reaction is themost preferred element for EPS production. In suspension polymerization, the particle sizeobtained from the reaction is very important. Parameters such as mixing speed, stirrer shape,reactor size and reactor geometry, reaction temperature and pressure affect the particle size.Furthermore, since suspension reaction is an exothermic reaction, temperature and pressureincrease during the reaction. This sitution negatively affects the reaction. Therefore, thereaction should be carried out at constant pressure and temperature. A batch reactor design hasbeen made considering this sitution and the necessary parameters.

In this study, machinability tests were executed. AA2024 aluminum alloy that are used in field of automotive and aero industries widely was preferred material in the experimental works. Effects of aging methods that were applied to AA2024 aluminum alloy on machinability were investigated. Test specimens obtained from T3 and T6 that are used methods for aging of AA20024 aluminum alloy, were machined with various cutting parameters (V: 150 m/min, 200 m/min, 250 m/min; F: 0.1 mm/tooth, 0.2 mm/tooth, 0.4 mm/tooth). The test specimens were machined on a CNC milling machine by using the L18 mixed model of Taguchi. Cutting forces (Fx, Fy, Fz) and surface roughness (Ra) were measured. Analysis of Taguchi and ANOVA were done for the results of test. The results showed that main effect factors of the cutting forces and surface roughness were federate and cutting speed. In addition, it was seen that the aging types caused a little effect on the cutting forces and surface roughness. It was determined that the T3 for cutting forces and T6 for surface roughness were very well.

In this article, the interfacial heat transfer coefficient (IHTC) is investigated as a function of superheat temperatures (100°C, 150°C, and 200°C) and casting heights (100, 150, and 200 mm). The experiments were conducted for a liquid alloy (Al-Si 12.9%) on water-cooled copper chill during vertically upward solidification of a eutectic Al-Si alloy casting. A finite difference method (FDM) is applied for the numerical used for solution of inverse heat conduction problem (IHCP), the so-called Beck's method. Computer-guided thermocouples were connected with the chill and casting, at six positions and the time-temperature data were recorded automatically. As the lateral surfaces are very well heat isolated, the unidirectional solidification process started vertically upward at the interface surface. The measured time-temperature data files were used by FDM using explicit technique. The experimental and calculated temperatures have shown excellent agreement. The IHTC increases as superheat temperatures increases. However, the casting height (100, 150, and 200 mm) has no significant effect on the IHTC. It changed only maximum peak values of the IHTC and increased air gap formation time with increasing casting height.