Complex-shaped Parts Research Articles

Manufacturing of Complex-Shape PM Products Consisting of Several Powder Elements

The article’s primary purpose is to give a technological assessment of manufacturing complex-shaped parts using powder metallurgy. The process is considered in the example of a complex-shaped product consisting of several elements manufactured separately from the Fe-C-Cu powder mixture and then combined into a single structure. The joining was carried out by impregnation of porous structural elements with the fusion of copper-containing material. It has been demonstrated that the infiltration process is affected by many factors: porosity of structural elements, wettability of their pore channels, fluid flowability of the infiltrating material, and other factors. The research was carried out on the mass products - centrifugal pump stages for oil production. The elements compaction was carried out on hydraulic press at a pressure of 500 MPa, which ensured the average density of the parts after sintering up to 7.8-8.4 g/cm3. During sintering and impregnation, various types of defects of the pieces were detected, which were caused by the excessive thickness of the infiltrating material, different densities of the walls, and insufficient wettability in the connection zones of the elements.The investigations have shown that manufacturing complex components by prefabricating single elements and their subsequent sintering combined with infiltration is feasible. It can be done in a chamber furnace as well as with belt sintering. However, it is necessary to carefully prepare the mold before sintering, choose the infiltrating agent, and analyse possible disadvantages.

Optimizing the Process Parameters of Hydro-Deep Drawing of Cylindrical Parts Using Fiber Metal Laminates

Forming Fiber Metal Laminates (FMLs) is still challenging. There are some inherent limitations to forming smaller and complex-shaped FML parts. In particular, the process parameters have a major impact on the final FMLs part. In this paper, several investigations were conducted to optimize these process variables. In the investigations, different Blank Holder Gap (BHG) thicknesses were used to predict the optimal range; variable Blank Holder Force (BHF) and Cavity Pressure (CP) were chosen to make the results more convincing. Based on the numerical analysis, it is found that the optimum BHF should be between 10 to 15 KN; CP has a range from 8 to 10 MPa; optimum BHG should be 1.0 mm. And through using these predicted process parameters, a successful Glare cup has been formed. Furthermore, the forming performance of the Glare material is improved and the laminate has shown better formability. Finally, optimized process variables can be used for mass production of FMLs parts.

Manufacture of complex shape parts by high-speed electromagnetic hydraulic forming method

Manufacture of complex shape parts by high-speed electromagnetic hydraulic forming method

In Situ Deformation Monitoring of 3D Woven Composite T-Profile Using MXene Nanoparticles.

The aim of this study was to develop a process-efficient smart three-dimensional (3D) woven composite T-profile by depositing MXene nanoparticles at the junction for sensing damage and deformation at the junction. Such smart composites could find application in the online health monitoring of complex-shaped parts. The composites were manufactured by infusing epoxy resin in a single-layer fabric T-profile preform, woven in folded form on a dobby shuttle loom using 300 tex glass roving. The chemically etched Ti3C2Tz MXene nanoparticles were dispersed in deionised water and 10 layers were sprayed at the junction of the composite to form a conductive coating. The MXene-coated composite T-profile specimens were subjected to tensile and fatigue loading to study the electromechanical response of the MXene coating to applied displacement. The results showed that the MXene coating was able to sense the sample deformation till ultimate failure of the composite. The MXene coating was also able to effectively sense the tensile–tensile fatigue loading, carried out at 2000 cycles and 4000 cycles for a 50 N–0.5 Hz and a 100 N–1 Hz load–frequency combination, respectively, while being sensitive to the overall deformation of the composite. The smart complex-shaped composites developed in this work were capable of monitoring their health under tensile and fatigue loading in real time.

Prediction of forming temperature in electrically-assisted double-sided incremental forming using a neural network

Electrically-assisted double-sided incremental forming (EA-DSIF) is a flexible forming method suitable for processing hard-to-form materials and complex-shaped parts. A challenge in EA-DSIF experiments is temperature measurement. Since the localized forming zone is blocked by the tools, it is not possible to measure the actual forming temperature distribution in the forming zone. To address this issue, we propose an artificial neural network (ANN) framework for predicting the forming temperature using measurements of the surrounding temperature and toolpath features. The ANN model was trained using the temperature outputs of finite element models. A simplified EA-DSIF simulation model was developed for computational efficiency needed for synthetic data generation. Model simplifications were justified in multiple cases and validated with experimental data by comparing the temperatures from positions that is visible to an infrared camera. The feasibility of applying the developed ANN model to untrained geometries and in practical applications was demonstrated. The findings generated from this study are crucial for selecting optimum process parameters, estimating the forming force, and predicting microstructure evolution during EA-DSIF.

Production and processing of pre-impregnated thermoplastic tapes by pultrusion and compression moulding

Although there is no doubt that composite materials are the future of lightweight structures and components, most of composites currently produced are made from thermoset polymers, which are not able to be recycled or reprocessed. In contrast, thermoplastic polymers offer the possibility to recycle and reprocess and when combined with a fibrous reinforcement, provide interesting mechanical properties. This work reviews the production of two thermoplastic pre-impregnated materials in a tape form, one of which is produced on new prototype equipment developed in our laboratories. The method for the production of tape is described, and the prepregs presented here were subjected to two processing techniques. The first processing method, pultrusion, is an efficient and autonomous method to produce composite profiles, marking itself as a continuous and cost-effective way to produce these materials. Pultrusion bars were then subjected to heated compression moulding, a process that allows to obtain more complex-shaped parts. The second method, heated compression moulding, is a relatively simple process which was used to obtain composite laminates. The pultrusion bars and composite laminates were then subjected to mechanical testing to evaluate the levels of consolidation of the final material. A microscope testing was also carried out to analyse the dispersion of fibres and polymer, as well as the amount of voids present in the composite.

Investigation on electron beam welding of dissimilar wrought/selective laser melting AISI 304 stainless steel plates

The selective laser melting (SLM) process gives a possibility to create complex shape parts. Joining SLM alloy parts to similar or dissimilar alloy parts can overcome some product design limitations such as limited dimensions and residual stress concentration. In this study, successful electron beam joining work on to SLM AISI 304 stainless steel plates was performed. The influence of beam current on the weld bead profile was investigated. Typical welded joints were analyzed by microstructure, microhardness, and tensile tests. The optimal welding parameters were obtained accordingly. A thorough analysis of the element and microstructure distribution in SLM and its influence on the properties of the welded joints were also investigated.

Build quality evaluation of a series of lattice structures of AlSi10Mg using X-ray tomography

Additive manufacturing is a manufacturing technology that has grown from prototyping applications to the production of end-use parts in various industries. It is today possible to produce complex-shaped parts such as cellular or lattice structures in various popular metal alloys relevant to engineering applications. These intentionally designed porous metamaterials allow unique properties that have applications in next-generation aerospace components and medical implants, amongst others. The wide adoption of lattice structures has been in part held back by quality concerns in the manufactured material, including porosity, surface roughness, microcracks, residual stress and microstructural nuances. These issues are generic to all AM materials, but at the scale of lattice structures they have a stronger influence on mechanical and other performance; and are more critical to the successful manufacturing and final application. While lattices have widely studied in the last few years, few comparisons of build quality exist for different designs or architectures. In this work, using the laser powder bed fusion process with AlSi10Mg alloy, we report an extensive and detailed characterization of the build quality of a range of different cellular architectures, utilizing X-ray computed tomography (CT). Some key conclusions are made that can be used to inform future designs, enhancing build success and design confidence. Some recommendations are made regarding the use of CT for lattice structure characterization.

High-Performance Processing of Complex-Shaped Parts Using Combined Methods

This article describes application of the method of turning the cylindrical surface of the part using the flank surface of the cutting plate. The comparison of classical turning and the use of ‘back turning’ was carried out, the area of rational application was revealed and the combined use of the methods was proposed. A finite element model of the part, tool and equipment was created for calculating deformations in the system and internal stresses. A control program for part machining using a combination of both machining methods was designed.

METHOD OF "SKELETAL STRUCTURES" TO SIMPLIFY THE PARAMETRIZATION PROCESS IN AUTOCAD

The article considers the method of "skeletal structures", proposed to simplify the process of parameterization. When parameterizing objects whose shape has more than one contour, there may be some complications, namely: auto-overlay dependencies, or sequential parameterization of the relative position of image fragments, can lead to an excessive number of dependencies, which can lead to inconsistencies when performing parameterization . The proposed method allows you to minimize such inconveniences, reduce the number of superimposed parameters and improve the quality of control over the shape of the object. The stages of parameterization of objects by the method of "skeletal structures" are formulated and characterized and recommendations for its use are given.
 The method of "skeletal structures" was developed and applied in the process of studying the topic "Parameterization" of the course "Engineering and Computer Graphics" at the Department of Descriptive Geometry, Engineering and Computer Graphics of the National Technical University of Ukraine "Kyiv Polytechnic Institute named after Igor Sikorsky". The application of the method on the example of flat parts of complex shape and for the structures used in the study of the topic "Assembly drawing" is demonstrated. As a condition of the task in the topic "Assembly drawing" we used a parameterized folding unit, which students adjusted to the parameters corresponding to the variant of the task, and supplemented the drawing with simplified images of fastening threaded elements made by them in the form of dynamic blocks.

Особенности азотирования поверхности мелкомодульного зубчатого венца в импульсно-периодическом газовом пучково-плазменном образовании при низком давлении

The paper presents the results of a study of the homogeneity of the thickness of the modified layer on the surface of a tooth crown made of structural steel 38Cr2MoAl with a tooth modulus m = 0.5 and the number of teeth 14, obtained as a result of ion-plasma nitriding in a beam-plasma formation generated in a stationary and pulse-periodic non-self-sustained glow discharge with a hollow cathode at low, about 1 Pa, pressure. The thicknesses of the nitrided layer at the top and at the base of the tooth obtained at the discharge pulse duty cycle γ = 100, 85, and 50%. It is shown that the minimum difference in the thickness of the nitrided layer, which is about 6%, is characteristic of the regime with a discharge pulse filling coefficient γ = 85%. Gas beam-plasma formations formed at low pressure are promising in the processes of ion-plasma nitriding of parts of complex shape.

Studying the Processes that Take Place in Vibroabrasive Machining of Complex-Shaped Parts

Studying the Processes that Take Place in Vibroabrasive Machining of Complex-Shaped Parts

Additive manufacturing of aluminum nitride ceramics with high thermal conductivity via digital light processing

Aluminum nitride (AlN) powder systems for additive manufacturing (AM) via digital light processing (DLP) were successfully developed, shaped by a DLP-based manufacturing technique, and sintered at 1700 °C. Properties of the AM parts were compared to reference samples consolidated via cold-isostatic pressing. AlN powders from two different manufacturers were used in the powder mixtures, underlining the flexibility of the process. Thorough process control was crucial for obtaining materials with a high degree of densification, exhibiting microstructural, thermal, and mechanical properties comparable to conventionally processed reference materials. Thermal conductivity of AM samples exceeded 160 W m−1 K−1, while flexural strength of AM samples varied between 320 and 498 MPa, depending on the orientation of specimens with respect to the building direction. The feasibility of this approach to generate complex-shaped parts was successfully shown by fabrication of crack-free demonstrator parts, highlighting prospective novel use cases in advanced heat management applications.

Study of Microstructure and Mechanical Properties of As-built and Heat-treated Additive Manufactured Inconel 718 Alloy

Additive manufacturing technology is becoming popular in the industry because it allows the manufacturer to fabricate cost-effective, strong, lightweight, and complex-shaped parts directly from 3D design data as compared with the conventional manufacturing method. Inconel 718 alloy is the most demanding material in aviation as well as in the automobile industry, in terms of manufacturing high-performance parts. In this study, Inconel 718 samples were built using the direct metal laser sintering process, and standard heat treatment was performed on the samples to improve their microstructure and mechanical properties. The as-built samples exhibited good grain structure with fine laves phases, but the matrix was free from ?' and ?" phases. During the heat treatment, the strengthening phases ?' and ?" precipitated. The mechanical properties of as-built and heat-treated samples were analysed and compared. Tensile tests revealed that the direct-aged sample had the higher tensile strength compared with the other conditions, whereas the as-built samples had higher ductility. Finally, fractography and microstructure analysis were performed to measure the failure modes of tensile specimens.

Study on the Soft Magnetic Properties of FeSiB/EP Composites by Direct Ink Writing

Fe-based amorphous alloy has excellent soft magnetic properties; traditionally, Fe-based amorphous alloy such as soft magnetic devices was fabricated by insulation enveloping and suppression molding methods. In this process, the aging of organic envelope materials and the crystallization of Fe-based amorphous alloy were usually occurring, accompanying with low magnetic induction and poor mechanical properties. The direct ink writing (DIW) technique can make complex-shaped parts and needs no heating treatment after forming, which can avoid the effect of traditional molding process. In the present study, varying mass fraction FeSiB/EP composite parts were prepared by the DIW technique with the Fe-based amorphous alloy powder and epoxy resin, in which microscopic morphology, magnetic properties, and mechanical properties of FeSiB/EP soft magnetic composites were studied. The results indicate that the slurry with iron powder mass fraction of 92.3, 92.6, and 92.8 wt% has good printing performance and self-support ability, which is suitable for DIW. The density of the printed parts is about 4.317, 4.449, and 4.537 g/cm3, which is almost similar with the iron powder. The tensile strength and elongation of printing parts are significantly improved compared with the pure epoxy resin. From the photos of microscopic morphology of printing parts, it can be seen that FeSiB powders are evenly dispersed in EP, no pores, and defects, with the proportion increasing of powders; the insulation coating thickness decreases; and the magnetic performance improves. The optimal sample is 92.8 wt% FeSiB/EP, in which saturation magnetic induction strength is 137.9759 emu/g and coercivity is 4.6523 A/m.

Структурные и механические свойства нержавеющей стали, сформированной в условиях послойного сплавления проволоки электронным лучом

Introduction. As of today, additive technologies are among the most promising methods to manufacture various parts. They allow producing parts of complex shapes and provide their quality structure. The quality of the structure formed depends on numerous parameters: equipment type, its operation mode, materials, shielding medium, etc. Large international companies producing 3D-printers provide technological guidelines for working on it. Such guidelines include the information on the manufacturers of raw materials (printing powders), products their equipment can work with and the operation modes that should be used with such powders. These parameters should be investigated to use it on the domestic equipment developed within the framework of research programs and import substitution programs. The researchers and developers of 3D-printing equipment frequently run into a problem of using currently available raw materials for obtaining parts possessing minimal porosity, uniform structure and mechanical properties similar to that of at least cast blanks. One of the widely used materials for 3D-printing is stainless steel. It has high corrosion resistance, which reduces the requirements to the medium in which 3D printing is carried out. Manufactured stainless steel products have a good combination of strength and plastic characteristics. The aim of the study is to obtain stainless steel specimens possessing minimal number of micro- and macro-defects and uniform structure by the method of wire arc additive manufacturing using an electron-beam setup developed at Tomsk Polytechnic University. The methods to study the AISI 308LSi stainless steel 3D-printed specimens are as follows: XRD analysis, tomography, chemical analysis, metallographic analysis, microhardness testing. Results and discussion. It is established that the AISI 308LSi stainless steel specimens manufactured using the electron-beam 3D-printing setup contain no macro-defects in the bulk of the specimens. There are small microdefects represented by residual gas pores with the dimensions of no more than 5.2 μm. The microstructure of the specimens is formed close to that of coarse-grained cast austenite steels and consists of columnar grains of the γ-Fe austenite matrix and high-temperature ferrite. The interfaces between the wire layers are not pronounced; however, there are small differences in phase composition. Based on the analysis of the results obtained, it is established that the use of electron-beam 3D-printing for the manufacture of parts from AISI 308LSi steel gives a structure similar to cast austenitic steels. Macro-defects do not appear, and the number of gas pores is small.

Characterization of Cobalt-Based Stellite 6 Alloy Coating Fabricated by Laser-Engineered Net Shaping (LENS).

The results of microstructure and mechanical properties evaluation of a Stellite 6 (Co-6) alloy deposited on X22CrMoV12-1 substrate by the laser-engineered net shaping (LENSTM) technology are presented in this paper. The Stellite 6 alloy is widely used in industry due to its excellent wear resistance at elevated temperatures and corrosive environments. Specific properties of this alloy are useful in many applications, e.g., as protective coatings in steam turbine components. In this area, the main problems are related to the fabrication of coatings on complex-shaped parts, the low metallurgical quality of obtained coatings, and its insufficient adhesion to a substrate. The results of recently performed investigations proved that the LENS technology is one of the most effective manufacturing techniques of the Co-6 alloy coatings (especially deposited on complex-shaped turbine parts). The microstructural and phase analyses of obtained Stellite 6 coatings were carried out by light microscopy techniques and X-ray diffraction analysis. A chemical homogeneity of Co-6 based layers and a fluctuation of chemical composition in coating–substrate zone after the laser deposition were analyzed using an energy dispersive X-ray spectrometer coupled with scanning electron microscopy. The room temperature strength and ductility of the LENS processed layers were determined in static bending tests.

Technological tests of a multi-seat device for vibro-shock processing of long parts of complex shape

The article deals with the issues related to the possibility of ensuring the indicators of quality of long complex-shaped parts by using vibration-impact processing in the technological process of their manufacturing using a special multi-seat device. The analysis of the design of representatives of long parts and the requirements for the quality of their surface layer, as well as the operational properties, made it possible to formulate the basic requirements for the design of multi-seat tools and develop a prototype for technological tests. The device allows processing two fragments of long parts and was used to establish the possibility of processing full-sized products and to establish optimal processing modes. Elements of the helicopter spars, which have the most complex design in the class of the considered parts, were used as fragments. Particular attention is paid to the processing of the inner surface of a complex shape and variable cross-section. The test results showed the possibility of using a multi-seat device for vibration-impact hardening treatment, which ensures the achievement of the specified parameters of the surface layer: surface roughness and microhardness with high process productivity.

Two-stage magnetic-elasto-pulse stamping of thin sheet parts

The article substantiates the use of preliminary static loading and subsequent forging force when stamping thin sheet parts of complex shape with an elastic punch. The static load provides a relative deformation of the order of 20– 30% in the processing zone, which guarantees the stability of the position of the workpiece during subsequent pulsed loading. This technique is very important in the manufacture of asymmetric parts with a thickness of 0.01 – 0.3 mm. As a result, the accuracy of the products obtained corresponds to the 7th grade.The article provides a schematic diagram and a description of the proposed design of a double-action press, and analyzes the cyclogram of the device.It is recommended to carry out a static load with an electric drive, a pulsed one with a magnetic hammer, which is connected to a generator of impulse currents with a capacitive storage with an energy capacity of up to 40 kJ with a natural discharge frequency of the current of 20 kHz.

Оценка целесообразности применения аддитивных технологий в изделиях аэрокосмической техники

The paper studies the feasibility of using additive technologies in the manufacture of parts of complex shapes for aerospace products. The results of the structural analysis of a part helped find the directions of topological optimization and optimize the part’s design. To confirm the relevance of the design optimization, we carried out static and dynamic strength calculations in the Siemens NX software package. The paper considers technologies for manufacturing the part by 3D metal printing and traditional milling on a numerically controlled machine. In order to obtain initial data for economic calculations, we simulated manufacturing processes in various software systems. To study the feasibility of metal printing technology, we carried out its technical and economic analysis, and found that the production program, technological processing modes and the cost of materials affect the cost of the product.