Complex-shaped Parts Research Articles

Analysis of cut orientation through half-finished product using WEDM

ABSTRACTWire electrical discharge machining (WEDM) is a non-traditional technology utilized to manufacture parts of complex shapes or machining the materials conventionally difficult to process. It is also applied in the aerospace industry, where Inconel 625, which was the subject of the research in this study based on aDesign of experiment (DoE), is usually machined. In this way, the experiment contained 33 rounds during which the settings of machined parameters were changed systematically. An identical experiment (33 rounds) was performed in which the semi-finished product was rotated by 90° to define the impact of the orientation direction of the cut on the speed of cutting and the quality of the surface and subsurface layers. Subsequently, a complex analysis of the machined surfaces of the individual samples was performed, including both the surface and subsurface layers. Topography was evaluated using a non-contact profilometer, including the creation of a color-filtered 3D surface relief. The subject of further investigation was the analysis of morphology and surface defects including the chemical composition analysis. For a very detailed observation of the distribution of the individual elements in the material, lamella was prepared, which was subsequently studied using a Transmission Electron Microscope (TEM). For the subsurface layer study and its defects, metallographic preparations of all samples, which were observed using both light and electron microscopy, were prepared. On the basis of the analyses performed, the impact of the cutting direction on the cutting speed as well as the machined surface quality was determined.

Joining of elements fabricated by a robotized laser/wire directed energy deposition process by using an autogenous laser welding

A robotized laser/wire directed energy deposition (RLW-DED) process has been employed, specifically in applications where higher deposition rates or larger buildup envelopes are needed. However, this process might have limitations in printing certain complex shape parts. Fabricating parts with overhang sections, depending on the geometry, might cause a collision between the laser head and the buildup. Part segmentation and joining the elements back together has been presented to overcome those limitations. In this study, the welding of additively manufactured parts by RLW-DED has been proposed. Autogenous laser welding, performed at the same setup used for RLW-DED, was utilized to join the thin-walled 316LSi DED parts. Mechanical and microstructural testing were then performed on the welded samples. The results showed that the mechanical properties of welded DED parts are comparable with those of DED parts. Furthermore, a component of complex shape was fabricated to show the capability of the developed process. Therefore, the welding of RLW-DED parts can expand the application of 3D-printed parts in industry.

Fabrication of micro punching mold for micro complex shape part by micro EDM

Micro punching process is suitable for mass production of micro parts. It is a challenge to fabricate micro punching mold with complex cross-sectional shape on-machine. The micro punching system’s structure design has to meet the requirement of large punching force. In this study, a micro punching system has been developed with a micro electrical discharge machining (EDM) module. A series of machining operations, from the fabrication of micro molds to punching, have been completed with no secondary clamping error. The micro die and reversed electrode are prepared using micro EDM milling. The micro punch is fabricated using reversed electrode. The punching clearance is around 11 μm. Complex shape punched holes and blanked parts have been successfully fabricated on copper, brass, 304 stainless steel, and 3J21 alloy. After punching, there was no damage on the edges of micro die and micro punch. The key dimensional error of blanked part varies by different materials, which is less than 2.5 μm.

Review of the Hard-Facing Technology Application for Reparation of the Given Parts in Various Branches of Industry

Abstract This paper deals with the problem of defining the optimal procedure for reparation of the machine parts of large dimensions and complex shapes. The procedure consists of establishing the causes of the part's damages, definition of the reparation technology, with selection of its parameters and ways of execution. The reparation is done by hard-facing, with heat treatment that consists of preheating, additional heating and the post hard-facing tempering. The process parameters' selection includes choosing the right filler metal(s), ways and order of depositing the hard-faced layers, ways of reaching and maintaining the preheating temperatures, checking of the base metal's chemical composition and mechanical properties and deciding on the post-process heat and mechanical processing of the executed hard-facing. The executed reparation of the forging hammer's mallet, presented in details, serves as an example how the reparation can successfully serve as a substitute for procuring the new part and thus producing the savings both directly in lower costs and indirectly in shortening the down-time of the damaged part operation.

Development and research of a device for gas sheet stamping with a piston pressure multiplier

Traditionally, sheet stamping is carried out in the cold state of the workpiece being processed. At the same time, due to the limited plasticity of the workpiece, stamping parts of complex shape is performed in several operating steps, which significantly increases the cost of production. The article is devoted to the development and research of a device providing stamping of parts with heating of the workpiece being processed. The device comprises a die and a working cylinder between which the workpiece is placed, as well as a combustion chamber separated from the working cylinder by a piston. The heating of the sheet billet and its punching is carried out in two stages within 1...2 s with its exposure to the action of gas mixture combustion products. At the first stage, the billet is heated and deformed by the combustion products formed in the die cavity and the working cylinder, whereas at the second stage these processes take place due to the energy of the combustion products formed in the combustion chamber. The workflow of the developed device was studied. The regularities of the pressure and temperature changes of the gas that heats and deforms the billet being stamped were established. The optimum proportions of the volumes of the combustion chamber and the working cylinder were determined. The developed device ensures stamping of complex-shaped parts in one process step due to the heating of the workpiece. In this device the pressure on the surface of the workpiece being processed is 2...3 times higher compared with the existing analogues, which ensures stamping of heavy-thickness parts, as well as parts made of hard-to-deform alloys.

Thirty Years of Superplastic Ultrafine-Grained Materials: Examining the Legacy of Oscar Kaibyshev

The occurrence of superplasticity may be traced to the classic work of Pearson conducted in the U.K. in 1934 when an elongation of 1950% was reported in a Pb-Sn eutectic alloy. Subsequently, much attention in Russia was devoted to this scientific curiosity and this led to the first book on superplasticity written by Prof. A.A. Presnyakov and published in 1964. Later, in 1985, Oscar Kaibyshev established in Ufa the Institute of Problems of Superplasticity of Metals of the Russian Academy of Sciences and this was, and remains to this day, the only institute in the world devoted exclusively to studies of the phenomenon of superplastic flow and the development through superplastic forming of complex-shaped parts. An important development occurred in 1988 with the publication of a classic report by Kaibyshev and co-workers describing the potential for achieving low temperature superplasticity in a metallic Al-Cu-Zr alloy that had been specially processed by severe plastic deformation (SPD) to produce a remarkably small grain size of only 300 nm. This report formed the basis for the later development of SPD processing as a major tool for the production of exceptional grain refinement and as a procedure for achieving large superplastic elongations that cannot be achieved using more conventional processing. This report describes this early work, the subsequent developments and the modern status of superplastic flow in ultrafine-grained metals.

Cryo-Ultrasonic NDE: Ice-Cold Ultrasonic Waves for the Detection of Damage in Complex-Shaped Engineering Components.

Recent advances in computational methods, materials science, and new manufacturing processes are resulting in an unprecedented design flexibility which is driving the geometrical complexity of the components found in modern structures and machines. For safety-critical components, the geometrical complexity poses a significant challenge to the sensitivity of the existing nondestructive evaluation (NDE) methods available for the detection of manufacturing defects or damage that develops while a component is in service. Although X-ray computed tomography is the primary NDE method used to test these parts in current industrial practice, it is widely recognized that it has limited sensitivity to critical defects, such as cracks, especially in the presence of large size parts made of dense materials. The lack of sensitive NDE methods represents a major technology gap that could impede the acceptance of rapidly developing technologies, such as 3-D printing, for the production of safety-critical components. This paper attempts to bridge this gap by exploring the possibility of inspecting a complex-shaped part with ultrasonic waves after it has been encapsulated in ice, under the paradigm of what can be defined as cryo-ultrasonic NDE. The underpinning hypothesis is that through ice encapsulation a complex-shaped part can be transformed into a simple-shaped solid whose volume can be probed with ultrasonic waves, which are known to be highly sensitive to both pores and crack-like defects and over a wide range of material properties. Damage detection is then performed by analyzing cross-sectional images of the ice-encapsulated part obtained by applying migration methods to the ultrasonic signals measured by an array of transducers. This paper lays the foundation for cryo-ultrasonic NDE and presents the first experimental results demonstrating the possibility of imaging defects through multiple ice-metal interfaces. This paves the way to the detection of defects in complex-shaped parts containing internal vanes which have so far limited the use of conventional NDE methods.

Últimos avances en la fabricación aditiva con materiales metálicos

La aparición de la fabricación aditiva ha sido y es una de las grandes revoluciones industriales de las últimas décadas. Las diversas tecnologías de fabricación aditiva permiten la creación de piezas con formas muy complejas, muy difíciles de fabricar antaño, en las que además el desperdicio de material es prácticamente inexistente. La fabricación aditiva no solo sirve para la creación de maquetas, si no que se pueden crear piezas perfectamente funcionales, para ello, se suelen emplear materiales metálicos. Este artículo explora la evolución de las diferentes tecnologías de fabricación aditiva con materiales metálicos. Está dividido en cuatro secciones principales en las que se define la fabricación aditiva, se exponen los hitos más importantes de su reciente historia, se definen las tecnologías y materiales más característicos y se comentan los retos y las perspectivas de futuro de la misma.

Features of technological basing in machining parts on CNC machines

The article discusses the problems of computer aided design and technological preparation of production of complex shape parts on machines with numerical program control. An integrated technique for designing processes and control programs for CNC machines is proposed and described, using the technique of software-based referencing and modern electronic measuring tools.

Evaluation of Flexural properties of the U-shape Composite Spring.

CFRP (carbon fiber reinforced plastics) which provides high specific strength/stiffness is adopted in assistive products such as orthosis for relieving the physical burden of patients. The orthosis needs the flexible configuration of articulations like walking of normal subjects. Since the CFRP autoclave method is suitable for molding complex shape parts, a structural component containing a partially curved region such as U-shape can be integrally molded by the method. Flexibility characteristics are added to a structural component without an increase in the number of parts. In this study, the flexibility of CFRP was evaluated for embedded light and durable springs into orthosis. First, three-point bending tests of the flat laminate were performed to assess the advantage of CFRP used as spring materials. Second, the flexural properties and fracture mechanism of a U-shape spring were investigated in comparison with the results of the flat laminate. The study confirmed the advantage of CFRP employed as a spring material.

Reducing Machining Time by Pre-Process Control of Spindle Speed and Feed-Rate in Milling Strategies

This article focuses on the issue of controlling cutting conditions in point milling strategies in order to reduce machining time. Using cutting tools with a circular cutting edge during point milling strategies of complex shape parts the actual contact point between the tool and the workpiece continuously changes. According to this fact the cutting speed also changes continuously and the required cutting speed is not achieved along the toolpath. Therefore, a solution to control the spindle speed has been developed to achieve the constant value of cutting speed and consequently provide a solution to control the feed-rate in order to maintain the constant value of feed per tooth. Application of this optimization technique has been demonstrated by means of a real machining test. The machined surface quality improvement and machining time savings were proven.

Wear-resistant polyetheretherketone composites: with carbon nano- and microfibers

Mechanical and tribotechnical properties of polyetheretherketone (PEEK) composites filled with carbon nanotubes/nanofibers (CNT/CNF) and short carbon fibers (SCF) were studied. It is shown that mechanical properties vary slightly when loading CNF/CNT. Enforcement by SCF gives rise to increasing elasticity modulus up to 2times. Loading of 0.3wt.% CNF/CNT ensures enlarging wear resistance of PEEK composites by 2times. At the SCF loading 30wt.% the wear resistance might be increased by 8times. The prospects of use antifrictional PEEK nano- and microcomposites in additive manufacturing for fabricating complex shape parts are discussed.

Identification of the anisotropic elastic and damping properties of complex shape composite parts using an inverse method based on finite element model updating and 3D velocity fields measurements (FEMU-3DVF): Application to bio-based composite violin soundboards

Inverse methods have been used for decades to identify material properties, in parallel, or as a substitution for direct methods. Although it has proven a useful method for many types of materials and simple geometrical shapes, it has barely been used on complex shape parts. This is the main objective of the non-destructive method proposed in this study. The proposed inverse approach, based on both vibrational experiment data and Finite Element Model Updating (FEMU), is successfully applied to a violin soundboard made of flax-epoxy composite. Results show that, by minimizing the discrepancy between the experimental and numerical data, three rigidities and three loss factors can be determined simultaneously. The identified values of the constitutive elastic moduli and longitudinal loss factor are in agreement with those determined using quasi-static tests and dynamic mechanical analysis.

Design Process Control for Improved Surface Finish of Metal Additive Manufactured Parts of Complex Build Geometry

Metal additive manufacturing (AM) is increasingly used to create complex 3D components at near net shape. However, the surface finish (SF) of the metal AM part is uneven, with surface roughness being variable over the facets of the design. Standard post-processing methods such as grinding and linishing often meet with major challenges in finishing parts of complex shape. This paper reports on research that demonstrated that mass finishing (MF) processes are able to deliver high-quality surface finishes (Ra and Sa) on AM-generated parts of a relatively complex geometry (both internal features and external facets) under select conditions. Four processes were studied in this work: stream finishing, high-energy (HE) centrifuge, drag finishing and disc finishing. Optimisation of the drag finishing process was then studied using a structured design of experiments (DOE). The effects of a range of finishing parameters were evaluated and optimal parameters and conditions were determined. The study established that the proposed method can be successfully applied in drag finishing to optimise the surface roughness in an industrial application and that it is an economical way of obtaining the maximum amount of information in a short period of time with a small number of tests. The study has also provided an important step in helping understand the requirements of MF to deliver AM-generated parts to a target quality finish and cycle time.

Experimental Investigation of Surface Layer Properties of High Thermal Conductivity Tool Steel after Electrical Discharge Machining

New materials require the use of advanced technology in manufacturing complex shape parts. One of the modern materials widely used in the tool industry for injection molds or hot stamping dies is high conductivity tool steel (HTCS) 150. Due to its hardness (55 HRC) and thermal conductivity at 66 W/mK, this material is difficult to machine by conventional treatment and is being increasingly manufactured by nonconventional technology such as electrical discharge machining (EDM). In the EDM process, material is removed from the workpiece by a series of electrical discharges that cause changes to the surface layers properties. The final state of the surface layer directly influences the durability of the produced elements. This paper presents the influence of EDM process parameters: discharge current Ic and the pulse time ton on surface layer properties. The experimental investigation was carried out with an experimental methodology design. Surface layers properties including roughness 3D parameters, the thickness of the white layer, heat affected zone, tempered layer and occurring micro cracks were investigated and described. The influence of the response surface methodology (RSM) of discharge current Ic and the pulse time ton on the thickness of the white layer and roughness parameters Sa, Sds and Ssc were described and established.

Influence of Spray Angle on Distribution of WC-Co-Cr Coating Produced by HVOF Spraying

When high velocity oxyfuel (HVOF) sprays complex shape parts, it is almost impossible to maintain a fixed angle between spray flame and substrate surface. Studying the effect of spray angle on coating characteristics is necessary. The present study investigates the influence of the concave radius size on the deposition rate. As feedstock material, an agglomerated and sintered WC-10Co-4Cr powder with a size distribution of 15∼45 μm was used. For the spray experiments the process parameters were held constant, while the radii were selected of 10, 15 and 25 mm in concave profile. It has been generally shown that the spray angle has a great effect on coating deposition rate. The reduction of the spray angle results in a decrease of the deposition rate. A significant degradation of the coating properties is found less to 30°. The relationship between the coating's distribution and spray angle with different curvature radius was deduced.

Analysis of barriers to implement additive manufacturing technology in the Indian automotive sector

PurposeA spurt in the usage of additive manufacturing (AM) is observed in industrial applications to produce final parts along with rapid prototyping and rapid tooling. Despite the potential benefits of on-demand and on-location production of customised or complex shape parts, widespread implementation of this disruptive production technology is not yet visible. The purpose of this paper is to examine the various barriers to implement AM in the Indian automotive sector and analyse interrelations among them.Design/methodology/approachBased on the extant literature and discussions with industry experts, ten major barriers are identified. The authors use a modified Fuzzy interpretive structural modelling (Fuzzy-ISM) method to derive strengths of relationships among these barriers, develop hierarchical levels, and thereafter group and rank these barriers.FindingsISM diagraph is developed to demonstrate how the barriers drive one another. Production technology capabilities and government support emerge as the most critical factors, with high driving power and medium dependence.Research limitations/implicationsWhile identified barriers may be similar across the automotive industry, generalisation of results for interrelationships and ranks in other industries may be limited.Practical implicationsThe findings may be useful to managers to develop suitable mitigation strategies, and take more informed decisions, with individual focus, level focus or cluster focus.Social implicationsFindings clearly establish that the role of management and government is crucial in mitigating workers’ resistance to AM implementation.Originality/valueThis paper contributes to AM literature by the structured presentation of the barriers to implement AM in the Indian automotive sector. It also extends the Fuzzy-ISM method by presenting calculation of indirect relations using the appropriate max-product composition and in ranking the barriers.

Process of Shaped Metal Billets Production from Compositions Based on Iron Powder, Iron Oxide, and Binder

A new technology of metal billets production by molding and thermal treatment of compositions based on iron powders of medium dispersion, fine powders of iron oxide, and the thermosetting binder, which provides for the required physical and mechanical properties of the material, is proposed. It is found that, at a certain concentration and dispersion of the components of the solid phase, the injection and direct compression molding of parts of complex shape (similar to the MIM-technology) is possible at pressures from 70 MPa to 100 MPa ensuring uniform density over the cross section. The established stages of thermal treatment of compositions, thermal behavior and protective medium ensuring uniformity of products, and chemical composition of the product material are presented in the paper. The experimental and theoretical studies of the dimensional accuracy of steel products obtained by the developed technology were carried out, and it was discovered that the produced parts were of the precision of steel parts produced by MIM-technology.

Innovative approach to mass production of fiber metal laminate sheets

ABSTRACTAlthough, lightweight composite structures like sandwich panels and fiber metal laminates (FMLs) are greatly used as a superior material to produce modern structures to provide a substitutive item for monolithic metallic parts, but still there are some challenges in their forming process. There are some inherent limitations for forming FML parts. Also, because the strain of the fibers is limited, conventional approaches are not appropriate for forming complex-shaped laminate parts. Understanding the material behavior during the forming process is critical to find a new technique for relatively intricate and smaller FML parts. To understand the material behavior to present a new forming method, the finite element software and experiments are utilized and the thinning of layer thickness, stress distributions in different layers, and the fiber orientation are studied. Blanks made of intermittent glass fabric/fibers and Al 2024-O alloy sheets. The behavior of the material was appraised utilizing ABAQUS according to Hill yield criteria and then evaluated with the empirical outcomes. Results exhibited that FML parts manufactured by utilizing multilayer hydroforming can enhance the FML applications.

3D gel-printing of zirconia ceramic parts

Abstract 3D gel-printing (3DGP) is a new printing method, which is based on a 2-hydroxyethyl methacrylate (HEMA) gelation system to produce complex shape parts. In this study, the 3DGP process based on a water-based gelation system was used to prepare zirconia (ZrO 2 ) ceramic parts. The water-based ZrO 2 ceramic slurry with a solid volume fraction of 50 vol% was prepared and its rheological property was characterized. The surface roughness is Ra 8.90 µm on the printed green sample, and Ra 8.25 µm on the sample after sintered at 1520 °C for 2 h. The relative density, the Vickers hardness and the transverse rupture strength of the sintered sample are 97.6%, 14.4 GPa and 450 MPa, respectively.