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Three-dimensional (3D) printing is a breakthrough technology that is being researched, developed and applied extensively in many areas of production around the world. One particular application is Selective Laser Sintering (SLS), in which a high-powered laser turns powdered material into a solid mass; however, in Vietnam the research and application of laser sintering is not very widespread, yet determining the durability, especially the tensile strength, of products made from this printing technology is necessary. The parameters during installation have a significant effect on the characteristics of the printing elements, so they need to they need to be studied. In this project, we focused on the influence of printing parameters to be able to optimize them to achieve the highest tensile strength in the products. The process consisted of producing specimens with 2 parameters to be tested: laser power and feed. The experimental results on the tensile strength were collected, and the influence of the printing parameters of the finished product were charted and analyzed. The result of the project is that laser power is the most important printing parameters that influences tensile strength.

Three-dimensional (3D) printing is a method of additive manufacturing that involves creating objects by serial deposition for pre-production or production. After designing a 3D model with a CAD program, a processable file is customized to create a layered design, which is then printed. Although this technique costs more than traditional techniques, such as metal injection molding, metal 3D printing can significantly improve the production times of lightweight parts produced in small numbers. Furthermore, is improves flexibility, and is more able to produce complicated geometries that would not be possible with common methods, such as turning, milling or drilling. The fused deposition modeling technique uses a metal powder filament, which is pulled through a high-temperature extrusion nozzle, thus melting the material; after that, the printed parts are placed in the debinding station with a solvent to remove the wax from the powder. Finally, completed products are taken from the sinter furnace with inert gases. Depending on the material, different characteristics arise in the production process, and the produced parts manifest different mechanical properties. This paper describes some experiments performed on the fused deposition modeling method using stainless steel filaments, debinding Opeteon and a sinter furnace.

Ultrasonic Vibration-Assisted Machining (UVA) is a machining process that adds a micro-scale high frequency vibration to the motion of a cutting tooltip to interrupt the continuous interaction of tool - workpiece surface. A good point of machining with UVA is more effective than conventional processes such as lower machining forces, higher machining stability, less tool wear and better surface finishes. In molds fabrication with some narrow cavities having a conversion space diameter of less than 3mm will face many difficulties while low surface roughness is required. Low stiffness of technological system in these cases of finishing machining is the reason of a weak machining in high-speed cutting. The ability to achieve cutting speeds for surface finishing of this type in tight spaces is also an interesting application for UVA tools. This paper discusses the finishing machining tool design with UVA for milling machine in such as analyze of the main parameters, adding diagonal split and simulation of the generated vibration effects to evaluate the achieved results before fabrication by using the help of ANSYS.

The demand for vegetable consumption is essential issue to serve citizens. Excessive protective chemical elimination which is applied advanced solutions brings high effects being investigated by domestic and international scientists. In this report, research team conducted and designed the vegetable washing machine integrated with the ultrasonic power and Ozone microbubbles to wash out plentiful protective chemicals attaching to surfaces of leafy vegetables. Followingly, using Taguchi method for four kinds of vegetables including salad, water spinach, Chinese cabbage, and mustard greens verifies the effectiveness of solutions. Vegetable samples are treated soaking pool making ultrasonic wave and Ozone microbubbles raging from 1.0ppm to 2.0ppm. The practical results demonstrated that the method using the ultrasonic power and Ozone microbubbles has high effects on eradicating protective chemical on leafy vegetables.

In this paper, an induction heating system was applied to the heating stage in the injection molding process. Through simulation and experiment, the heating process was estimated by the temperature distribution and the heating rate. In the simulation, the mold temperature was increased from 30°C to 180°C in 9 s. Therefore, the heating rate was higher than 16°C/s, which represents a positive result in the field of mold heating. Additionally, the temperature distribution revealed that the higher temperature is concentrated on the gate area, while the outside of the mold cavity is at a lower temperature. The same parameters were applied to both the experiment and the simulation, and the results were in good agreement.

This paper presents modeling and simulation of spring-mass damper system for quarter car in the Simulink environment. The simulations in this research have been carried out by using the Simulink of Matlab. The parameters in the simulation model for the suspension system under study include car body mass, wheel mass, spring and damping elements of shock absorber, and tire. A road disturbance profile comprising a combination of two sinusoidal curves is modeled. Controllers that are used in this study are the proposed fuzzy logic controller. The purpose of this research is to improve vehicle comfort using the Fuzzy Logic Controller (FLC). The simulation results of the system perform well fulfill the minimum percentage requirements and fast stability time, provide good leveling of stability and ride comfort.

3D printing is a promising digital manufacturing technique that manufactures product parts in a layer fashion. Fused deposition modeling (FDM) is a widely used 3D printing technique that produces components by heating, extruding, and depositing the filaments of thermoplastic polymers. Meanwhile, the properties of FDM-produced parts are significantly influenced by process parameters. These process parameters have different advantages that need to be investigated. This paper examines the effect of some process parameters on the tensile properties of some components produced using FDM technique. The study is performed on polylactic acid (PLA) material, using full factorial experimental design. Furthermore, three process parameter—material, infill density, and infill pattern—are considered. The results indicate that only the infill pattern significantly influences the tensile properties of the model.

The determination of side-core for plastic moldings plays an important part in design process. Numerous studies have been investigated for side-cores recognition in literature. However, most of the existing methods have been developed based on the side-core surfaces of one region are known. In fact, it is difficult to identify relevant surfaces of one region. This study proposes a new algorithm of relevant surface attribution (RSA) based on topological relationship and V-map to automatically identify relevant surfaces of a side-core region. Then, the proposed approach defines the shape of side-core region as bounding surfaces and side-core direction. Finally, case studies are used demonstrating the applicability and usage of proposed approach.