Converting a CAD Model into a Manufacturing Model for the Components Made of a Multiphase Perfect Material

To manufacture the component made of a multiphase perfect material (including homogeneous and multi heterogeneous materials), it CAD model should be processed and converted into layered manufacturing model for further transformation of numerical control (NC) coding. This paper develops its detailed approaches and corresponding software. The process planning is made first and includes: (1) determining the build orientation of the component; and (2) slicing the component into layers adaptively according to different material regions since different materials have different optimal layer thickness for manufacturing. After the process planning, the layered manufacturing models with necessary information, including fabrication sequence and material information of each layer, are fully generated.Mechanical Engineerin

Octree-based production of near net shape components

Near net shape (NNS) manufacturing refers to the production of products that require a finishing operation of some kind. NNS manufacturing is important because it enables a significant reduction in: machining work, raw material usage, production time, and energy consumption. This paper presents an integrated system for the production of near net shape components based on the Octree decomposition of 3-D models. The Octree representation is used to automatically decompose and approximate the 3-D models, and to generate the robot instructions required to create assemblies of blocks secured by adhesive. Not only is the system capable of producing shapes of variable precision and complexity (including overhanging or reentrant shapes) from a variety of materials, but it also requires no production tooling (e.g., molds, dies, jigs, or fixtures). This paper details how a number of well-known Octree algorithms for subdivision, neighbor findings, and tree traversal have been modified to support this novel application. This paper ends by reporting the construction of two mechanical components in the prototype cell, and discussing the overall feasibility of the system

Latest Developments in Industrial Hybrid Machine Tools that Combine Additive and Subtractive Operations

Hybrid machine tools combining additive and subtractive processes have arisen as a solution to increasing manufacture requirements, boosting the potentials of both technologies, while compensating and minimizing their limitations. Nevertheless, the idea of hybrid machines is relatively new and there is a notable lack of knowledge about the implications arisen from their in-practice use. Therefore, the main goal of the present paper is to fill the existing gap, giving an insight into the current advancements and pending tasks of hybrid machines both from an academic and industrial perspective. To that end, the technical-economical potentials and challenges emerging from their use are identified and critically discussed. In addition, the current situation and future perspectives of hybrid machines from the point of view of process planning, monitoring, and inspection are analyzed. On the one hand, it is found that hybrid machines enable a more efficient use of the resources available, as well as the production of previously unattainable complex parts. On the other hand, it is concluded that there are still some technological challenges derived from the interaction of additive and subtractive processes to be overcome (e.g., process planning, decision planning, use of cutting fluids, and need for a post-processing) before a full implantation of hybrid machines is fulfilledSpecial thanks are addressed to the Industry and Competitiveness Spanish Ministry for the support on the DPI2016-79889-R INTEGRADDI project and to the PARADDISE project H2020-IND-CE-2016-17/H2020-FOF-2016 of the European Union's Horizon 2020 research and innovation program

A Review of Preparation and Characterization of Additively Manufactured Stainless Steel

في عالم اليوم، يعد التصنيع بالإضافة طريقة معروفة لإنشاء نماذج ثلاثية الأبعاد، إما من المعادن أو السيراميك أو البلاستيك أو مزيج من هذه المواد. يرتبط التصنيع بالإضافة بسلسلة من دورات التسخين والتبريد السريعة، فضلاً عن التدرجات الكبيرة في درجات الحرارة، مما يؤدي إلى تطوير تواريخ حرارية معقدة، والتي لها تأثير مباشر على الهياكل الدقيقة للمواد الناتجة. نظرًا لطبيعة هذه العملية الديناميكية والبعيدة عن التوازن، تظهر ميزات هيكلية مجهرية مختلفة. على سبيل المثال، من المحتمل أن تحدث تغييرات في خصائص التآكل للفولاذ المقاوم للصدأ المصنوع بتقنية الاضافة، والتي تتمتع بخصائص ميكانيكية فائقة ومقاومة للتآكل عند تصنيعها باستخدام طرق إنتاج أخرى. نظرًا لأن مثل هذه التعديلات غير مفهومة تمامًا في هذا الوقت، فإن التناقضات والاختلافات في الأدبيات المتعلقة بسلوك التآكل للفولاذ المقاوم للصدأ المصنوع مضافا تظهر بانتظام. يعد تحضير وتوصيف الفولاذ المقاوم للصدأ المصنوع مضافًا موضوع هذا العمل، والذي يوفر تقييمًا نقديًا. فيما يتعلق بإنتاج الهياكل المعدنية الضخمة بمعدلات ترسيب عالية وبتكلفة رخيصة، فقد برز التصنيع بالإضافة السلكي كطريقة قابلة للتطبيق. تستعرض هذه المقالة بعض طرق التصنيع بالإضافة المستخدمة في الغالب مع المواد المعدنية مع التركيز على التصنيع بالإضافة السلكي  من الفولاذ المقاوم للصدأ.In today's world, ADDITIVE MANUFACTURING (AM)  is a well-known method for creating true three-dimensional objects, either out of metals, ceramics, plastics, or a combination of these materials. ADDITIVE MANUFACTURING (AM)  is connected with a series of rapid heating and cooling cycles, as well as substantial temperature gradients, which result in the development of complicated thermal histories, which have a direct impact on the resulting microstructures. Due to the nature of this dynamic and far-from-equilibrium process, different microstructural features emerge. For instance, these are likely to induce changes in the corrosion characteristics of ADDITIVE MANUFACTURING (AM)  stainless steels, which have superior mechanical properties and corrosion resistance when manufactured using other production methods. Because such modifications are not fully understood at this time, inconsistencies and conflicts in the literature on the corrosion behaviour of ADDITIVE MANUFACTURING (AM)  stainless steels are regularly seen. The preparation and characterization of additively made stainless steel is the subject of this work, which provides a critical assessment. In terms of producing huge metallic structures at high deposition rates and cheap costs, WIRE ARC ADDITIVE MANUFACTURING  (WAAM)  has emerged as a viable method. This article reviews some ADDITIVE MANUFACTURING (AM)   methods used mostly with metallic materials focusing on the WIRE ARC ADDITIVE MANUFACTURING  (WAAM)  of stainless steel

Remanufacturing and Advanced Machining Processes for New Materials and Components

"Remanufacturing and Advanced Machining Processes for Materials and Components presents current and emerging techniques for machining of new materials and restoration of components, as well as surface engineering methods aimed at prolonging the life of industrial systems. It examines contemporary machining processes for new materials, methods of protection and restoration of components, and smart machining processes. • Details a variety of advanced machining processes, new materials joining techniques, and methods to increase machining accuracy • Presents innovative methods for protection and restoration of components primarily from the perspective of remanufacturing and protective surface engineering • Discusses smart machining processes, including computer-integrated manufacturing and rapid prototyping, and smart materials • Provides a comprehensive summary of state-of-the-art in every section and a description of manufacturing methods • Describes the applications in recovery and enhancing purposes and identifies contemporary trends in industrial practice, emphasizing resource savings and performance prolongation for components and engineering systems The book is aimed at a range of readers, including graduate-level students, researchers, and engineers in mechanical, materials, and manufacturing engineering, especially those focused on resource savings, renovation, and failure prevention of components in engineering systems.

Modeling the effects of concentration of solid nanoparticles in liquid feedstock injection on high-velocity suspension flame spray process

This paper presents the effects of the concentration of solid nanoparticles in the liquid feedstock injection on the high-velocity suspension flame spray (HVSFS) process. Four different concentrations of solid nanoparticles in suspension droplets with various droplet diameters are used to study gas dynamics, vaporization rate, and secondary breakup. Two types of injections, viz. surface and group, are used. The group-type injection increases the efficiency of droplet disintegration and the evaporation process and reduces the gas cooling. The initiation of the fragmentation process is difficult for small droplets carrying a high concentration of nanoparticles. Also, smaller droplets undergo rapid vaporization, leaving clogs of nanoparticles in the middle of the barrel. For larger droplets, severe fragmentation occurs inside the combustion chamber. For a higher concentration of nanoparticles, droplets exit the gun without complete evaporation. The results suggest that, in coating applications involving a higher concentration of nanoparticles, smaller droplet sizes are preferred

A study on the effects of plasma spraying parameters on the adhesion strength of Cr3C2-NiCr coating on 16Mn steel

This paper experimentally studied the adhesion strength of Cr3C2-30 %NiCr coating created on 16Mn steel substrate by plasma thermal coating technique in relation to spraying parameters. Experiments were carried out according to the central composite design (CCD) experimental matrix with three parameters: current intensity, powder feeding rate, and spray distance. Samples consisting of an annular disc and a latch made of 16Mn were fabricated according to the JIS H8664-1977 standard. Cr3C2-30 %NiCr coating was then created on the top surface of the disc including end of the latch. Adhesion strength of the coating to the substrate was measured through the tensile test. ANOVA analysis of variance was performed to evaluate the influence of the spraying parameters on adhesion strength and to build an empirical regression function representing the relationship between those parameters and the adhesion. Optimization problem was solved by ANOVA method and genetic algorithm (GA) to determine the value of the spraying parameters at which the coating has the greatest adhesion strength to the substrate. The results showed that the spraying parameters greatly affected the adhesion of the Cr3C2-30 %NiCr coating to the 16Mn substrate. Among them the spray distance has the greatest influence while the powder feeding rate has the least. Secondly, the regression function was well reflected the relationship between the three parameters and adhesion strength of the coating on the substrate. Using the values of spray parameter obtained from the GA optimization to create Cr3C2-30 %NiCr coating on 16Mn steel, the adhesion strength of the coating to the substrate reached a value of 98.4 % compared to the predictio