Papers by Keyword: Molding

Abstract: The features of calculating the thickness of the layers of bimetallic powder products without holes and the type of bushings are shown. The effect of the particle size distribution of the powders, the kinematic and geometric parameters of the loading devices and molds on the mechanism of the expiration of the powder mixture and on the thickness of the layers of the molded product is studied. A technique has been developed for determining the dimensions of the feeder cassette and tooling, depending on the overall dimensions and thicknesses of the working layers, in the production of whole-pressed bimetallic products on press machines with a vertical arrangement of layers. It was found that the thickness of each layer of bimetallic products depends on the geometric parameters of the feeder cassette and tooling, bulk density, particle size distribution and other characteristics of the powders, as well as on the speed of lowering the lower punch ν₁ .

Abstract: The work presents the thermodynamic calculations of the adiabatic combustion temperature and the fraction of the liquid titanium phase during the chemical reaction of the initial titanium and boron powders with the initial titanium content from 5 to 80 wt. % during the synthesis of materials based on TiB-Ti. It is shown that with an increase in the preheating temperature of the initial samples to 500 °C, the combustion temperature of the selected composition increases from 3200 to 3600 K, and the fraction of the liquid phase increases from 40 to 80 %. The peculiarity of molding composite materials based on TiB-Ti under conditions combining self-propagating high-temperature synthesis (SHS) and high-temperature shear deformation is studied. These conditions are realized in the method of free SHS compression, which allows synthesizing, molding and obtaining compact material in tens of seconds without using special molds. It was found that the maximum degree of deformation of the synthesized material corresponds to 20-40 wt. % free titanium. For the selected compositions, compact composite materials were obtained by free SHS compression method, the structural features were studied, and the density and porosity of the central and regional parts of the samples were measured.

Abstract: The paper presents the results of the development of the technology of centrifugal-die forming of biologically active fibrous materials. The modification of biologically active polypropylene fibers was carried out directly at the process of their production in the field of centrifugal forces of rotating reactor during their molding from polypropylene melt. The properties of the obtained ion-exchange and biologically active polymer fibers are studied. It is shown that obtained and modified by the centrifugal-die method polypropylene fibers can be used as biologically active fibers.

Abstract: This paper presents the results of the study of strength and fracture processes of FRP samples, obtained by vacuum and vacuum-autoclave molding methods. The experimental studies consisted of a three-point bending test with step loading, accompanied by an acoustic emission method. Based on the acoustic emission data recorded using the acoustic-emission software and hardware complex during the experiments, a method for estimating the accumulated damage using various techniques for analyzing acoustic emission parameters was tested. The results of methods for analyzing the power-law coefficient of accumulation of total AE, b-value and density distribution of amplitudes and median frequencies are considered. An estimate of the power-law coefficient of accumulation of the total AE made it possible to determine the bearing capacity of PCM samples. Using the techniques for analyzing the amplitude distribution of the AE signals and the distribution density of the amplitudes and median frequencies of the AE signals, destructive processes in the volume of samples were described and the stages of their damaging were revealed.

Abstract: The aim of this study was to determine the influence of casting technology on the structure of the ZnAl40Cu2Ti alloy. The scope of the examination included Brinell hardness tests and tests on optical microscopy, scanning electronic microscope test and X-ray microanalysis. The tests showed that, depending on the casting technology can be obtained different ZnAl40Cu2Ti alloy structure, characterized by different chemical composition in microareas. It has been pointed out that in order to get ZnAl40Cu2Ti alloy modification of Zn-Al-Cu alloy used technology casting is necessary.

Abstract: The demand for components manufactured by Metal Injection Molding (MIM) has been increased due to a diverse range of applications on the high temperature mechanical properties and corrosion/oxidation resistance. Super alloy utilize the inherent physical properties of heat-resisting alloy based on iron-nickel, or cobalt specifically high purity and fine particle size distributions, which can enhance sintering and maximize the density of the final component. The development of super alloy Inconel 718 (IN718) using MIM is discussed. IN718 powder with binder formulation consists of polyethylene (PE) / palm stearin (PS) were mixed homogeneously and injected to produce green compacts. The binders then were removed through solvent extraction process from various heating temperature and duration of time. The binder removal was quantified by weight loss measurements and the evolution of pore structure for the debound specimens was observed using scanning electron microscope (SEM). Result shows that complete extraction of PS from the green parts can be concluded during 60 °C of heating and 6 hours of immersion in heptane.

Abstract: Thermoplastic slip from commercial powders of yttrium nitride and yttrium oxide. The scheme of making the slip is proposed, the casting properties are determined. The influence of sintering additives dispersion and molding conditions (pressure, temperature) on slip properties is researched.

Abstract: The sponge membrane winding quality depends on the tension intensity and stability during the winding process. Taking the problem of winding system at dynamic procedure, this paper analyzed the dynamic relationship among velocity, tension and diameter of winding coil. On this basis, the design controlled invariable tension via changing the RPM of the motor and the PID controller ,the feed-forward decoupling controller also be utilized to compensate the tension simultaneously via adjusting the RPM of the motor. The simulation presents that the design has good dynamic responses and strong anti-interference capacity.

Abstract: The main requirements of preparation of composite materials in aerospace industry are affordable , highly automated and good quality control.To reduce the mold cost and shorten the production cycle, the aviation industry is focusing on weaving technology,advanced spread with technology, autoclave technology, injection process, advanced curing process;,all quality concept and thermoplastic process. The main principle of RTM process is laying reinforced material form in the cavity, in accordance with the requirements of performance and structure, injection equipment will be used by special resin system of closed cavity, mold has fastening , injection mould with peripheral seal and exhaust system, which ensures that the resin flow smooth out all the gas in the cavity side by side and infiltrating fiber thoroughly, it also has heating system, which is used as heating composite components of.curing forming.

Abstract: A molding process of aluminum foams by using a rotating mold is proposed in order to improve the mold filling and forming process for light-weight parts of vehicles. Aluminum powder mixed with a foaming agent is extruded into the mold through the die heated to a temperature higher than the melting point, and the mold is filled with the aluminum foam. When the diameter of a cylindrical mold is large, the influence of gravity is significant and the mold is not filled successfully. In the proposed molding, the aluminum foam is extruded into the rotating mold of large diameter and the volumetric ratio of foam to mold cavity is improved. However, the effect of the mold rotation on the mold filling is limited due to friction.