Performance-control-orientated hybrid metal additive manufacturing technologies:state of the art,challenges,and future trends

Metal additive manufacturing(AM)technologies have made significant progress in the basic theoretical field since their invention in the 1970s.However,performance instability during continuous processing,such as thermal history,residual stress accumulation,and columnar grain epitaxial growth,consistently hinders their broad application in standardized industrial production.To overcome these challenges,performance-control-oriented hybrid AM(HAM)technologies have been introduced.These technologies,by leveraging external auxiliary processes,aim to regulate microstructural evolution and mechanical properties during metal AM.This paper provides a systematic and detailed review of performance-control-oriented HAM technology,which is categorized into two main groups:energy field-assisted AM(EFed AM,e.g.ultrasonic,electromagnetic,and heat)technologies and interlayer plastic deformation-assisted AM(IPDed AM,e.g.laser shock peening,rolling,ultrasonic peening,and friction stir process)technologies.This review covers the influence of external energy fields on the melting,flow,and solidification behavior of materials,and the regulatory effects of interlayer plastic deformation on grain refinement,nucleation,and recrystallization.Furthermore,the role of performance-control-oriented HAM technologies in managing residual stress conversion,metallurgical defect closure,mechanical property improvement,and anisotropy regulation is thoroughly reviewed and discussed.The review concludes with an analysis of future development trends in EFed AM and IPDed AM technologies.

An Improved Hyperplane Assisted Multiobjective Optimization for Distributed Hybrid Flow Shop Scheduling Problem in Glass Manufacturing Systems

To solve the distributed hybrid flow shop scheduling problem(DHFS)in raw glass manufacturing systems,we investigated an improved hyperplane assisted evolutionary algorithm(IhpaEA).Two objectives are simultaneously considered,namely,the maximum completion time and the total energy consumptions.Firstly,each solution is encoded by a three-dimensional vector,i.e.,factory assignment,scheduling,and machine assignment.Subsequently,an efficient initialization strategy embeds two heuristics are developed,which can increase the diversity of the population.Then,to improve the global search abilities,a Pareto-based crossover operator is designed to take more advantage of non-dominated solutions.Furthermore,a local search heuristic based on three parts encoding is embedded to enhance the searching performance.To enhance the local search abilities,the cooperation of the search operator is designed to obtain better non-dominated solutions.Finally,the experimental results demonstrate that the proposed algorithm is more efficient than the other three state-of-the-art algorithms.The results show that the Pareto optimal solution set obtained by the improved algorithm is superior to that of the traditional multiobjective algorithm in terms of diversity and convergence of the solution.

Modeling thermal and mechanical cancellation of residual stress from hybrid additive manufacturing by laser peening

Additive manufacturing(AM)of metals often results in parts with unfavorable mechanical properties.Laser peening(LP)is a high strain rate mechanical surface treatment that hammers a workpiece and induces favorable mechanical properties.Peening strain hardens a surface and imparts compressive residual stresses improving the mechanical properties of a material.This work investigates the role of LP on layer-by-layer processing of 3D printed metals using finite element analysis.The objective is to understand temporal and spatial residual stress development after thermal and mechanical cancellation caused by cyclically coupling printing and peening.Results indicate layer peening frequency is a critical process parameter affecting residual stress redistribution and highly interdependent on the heat generated by the printing process.Optimum hybrid process conditions were found to exists that favorably enhance mechanical properties.With this study,hybrid-AM has ushered in the next evolutionary step in AM and has the potential to profoundly change the way high value metal goods are manufactured.

Subsurface Defect Evaluation of Selective-Laser-Melted Inconel 738LC Alloy Using Eddy Current Testing for Additive/Subtractive Hybrid Manufacturing

New materials and manufacturing technologies require applicable non-destructive techniques for quality assurance so as to achieve better performance.This study comprehensively investigated the effect of influencing factors includ-ing excitation frequency,lift-off distance,defect depth and size,residual heat,and surface roughness on the defect EC signals of an Inconel 738LC alloy produced by selective laser melting(SLM).The experimental investigations recorded the impedance amplitude and phase angle of EC signals for each defect to explore the feasibility of detecting sub-surface defects by merely analyzing these two key indicators.Overall,this study revealed preliminary qualitative and roughly quantitative relationships between influencing factors and corresponding EC signals,which provided a prac-tical reference on how to quantitively inspect subsurface defects using eddy current testing(ECT)on SLMed parts,and also made solid progress toward on-line ECT in additive/subtractive hybrid manufacturing(ASHM)for fabricating SLMed parts with enhanced quality and better performance.

Droplet-targeting laser hybrid indirect arc for additive manufacturing technology-A preliminary study

The contradiction between manufacturing accuracy and manufacturing efficiency is discussed in this paper.In order to solve this problem,a novel droplet-targeting laser hybrid indirect arc for additive manufacturing technology is proposed in which a couple of wires are melted using the alternating current with interwire indirect arc to achieve high deposition rate.On the other hand,droplets actively target the laser beam and detach from wire tip under the recoil pressure subjected to pulsed laser irradiating at desired position and with controlled mass for a precise bead forming.The process of alternative droplet growing at desired position are mathematically analyzed and then preliminary verified by experiment.By precisely controlling the wire feed speed and current frequency,the melting process at desired position and mass of wire is successfully obtained which is the fundamental for next-step for the droplet actively targeting laser.

An analysis of key process parameters for hybrid manufacturing by material extrusion and CNC machining

Hybrid Manufacturing combines the advantages of Additive Manufacturing (AM)and Subtractive Manufacturing on a single machine.Although previous research has provided a good background of the manufacturing parameters,the analysis is often carried out separately and there is a lack of combined knowledge.The purpose of this research is to examine the influence of the main manufacturing parameters involved in AM and subtracfive processes using different variables.Particularly,the study is focused on the Material Extrusion process concerning the layer height,fill angle and fill density;as well as two factors related to machining,including stepover and pass direction.The parameters that were examined include the dimension,hardness, flatness,weight and roughness.A mulfifactofial Design of Experiments was proposed with a total of 64 samples.Next,a statistical analysis was carried out to assess the influence of the different groups on the response variables.Finally,a decision table presented and facilitated the selection of parameters depending on the desired objectives,leading to a framework that was applied to a case study for validation.This decision guide could enable designers and engineers to select the best strategy for a specific application,leading to a more efficient approach for manufacturing.

Two-Machine Hybrid Flow-Shop Problems in Shared Manufacturing

In the“shared manufacturing”environment,based on fairness,shared manufacturing platforms often require manufacturing service enterprises to arrange production according to the principle of“order first,finish first”which leads to a series of scheduling problems with fixed processing sequences.In this paper,two two-machine hybrid flow-shop problems with fixed processing sequences are studied.Each job has two tasks.The first task is flexible,which can be processed on either of the two machines,and the second task must be processed on the second machine after the first task is completed.We consider two objective functions:to minimize the makespan and tominimize the total weighted completion time.First,we show the problem for any one of the two objectives is ordinary NP-hard by polynomial-time Turing Reduction.Then,using the Continuous ProcessingModule(CPM),we design a dynamic programming algorithm for each case and calculate the time complexity of each algorithm.Finally,numerical experiments are used to analyze the effect of dynamic programming algorithms in practical operations.Comparative experiments show that these dynamic programming algorithms have comprehensive advantages over the branch and bound algorithm(a classical exact algorithm)and the discrete harmony search algorithm(a high-performance heuristic algorithm).

Die Casting Mold Repair by Hybrid Manufacturing

This paper describes the process of repairing a damaged die for injection molding using a 5-axis Hybrid Milling Machine equipped with a Direct Laser Deposition(DLD)tool.A software developed by the authors—DUOADD—is adopted to detect the location of missing material and to create a solid model of the damaged spot.The resulting CAD file is used to calculate the paths of the DLD nozzle for filling the damage spot with new material.Finally,to restore the original shape of the mold,the surplus of added material is removed by a milling operation.The paper describes every step of the repair process:from 3D scanning of the damaged component to the finishing operation.This repair method can be applied to extend the life of a costly component and to restore the original shape of valuable objects—e.g.historical or artistic artifacts.The material used for the mold repair is stainless steel 316L,while the mold is made of hot-die-steel.In this paper the functionality of the repair process has been investigated by checking whether all the damaged spots are properly filled with new material.Moreover,this work investigates how to perform the milling operations that allow restoring the original shape of the object,minimizing mismatches between the machined surface and the original one.

Universal and efficient hybrid modeling and direct slicing method for additive manufacturing processes

Model design and slicing contour generation in additive manufacturing(AM)data processing face challenges in terms of efficiency and scalability when stereolithography files generated by complex functionally graded structures have millions of faces.This paper proposes a hybrid modeling and direct slicing method for AM to efficiently construct and handle complex three-dimensional(3D)models.All 3D solids,including conformal multigradient structures,were uniformly described using a small amount of data via signed distance fields.The hybrid representations were quickly discretized into numerous disordered directed lines using an improved marching squares algorithm.By establishing a directional HashMap to construct the topological relationship between lines,a connecting algorithm with linear time complexity is proposed to generate slicing contours for manufacturing.This method replaces the mesh reconstruction and Boolean operation stages and can efficiently construct complex conformal gradient models of arbitrary topologies through hybrid modeling.Moreover,the time and memory consumption of direct slicing are much lower than those of previous methods when handling hybrid models with hundreds of millions of faces after mesh reconstruction.

Enhanced high-temperature mechanical properties of laser-arc hybrid additive manufacturing of Al-Zn-Mg-Cu alloy via microstructure control

Recently,rapid and cost-effective additive manufacturing solutions for lightweight aluminum alloys with excellent high-temperature mechanical properties have been increasingly in demand.In this study,we combined laser-arc hybrid additive manufacturing with solution and artificial aging treatments to achieve Al-Zn-Mg-Cu alloy with favorable high-temperature strength via microstructure control.Hydrogen pores became the major defect in the as-deposited and heat-treated specimens.The continuous distribution of eutectics with hard-brittle characteristics at the grain boundaries was destructed following heat treat-ment.High-densityηprecipitates were uniformly dispersed in the heat-treated Al-Zn-Mg-Cu alloy,whereas appeared coarsened and dissolved at 473 K,owing to the rapid diffusion of Zn and Mg.The average 0.2%yield strength(318±16 MPa)and ultimate tensile strength(362±20 MPa)at 473 K af-ter heat treatment were enhanced by approximately 58%and 51%,respectively,compared to those of the as-deposited specimen.In addition,theηprecipitates contributed to lattice distortions and strain fields,which prevented dislocation motion and increased slip deformation resistance at high temper-atures.The as-deposited specimen exhibited intergranular fracture at 473 K,with cracks preferring to propagate along the aggregated eutectics.However,crack propagation proceeded in the sections with more pores in the heat-treated specimen.Our approach may provide a valid option for achieving alu-minum alloys with excellent high-temperature mechanical properties.

Sustainable manufacturing for obsolete computers based on 3R engineering

The volume tendency of in-use and end-of-life computers in China were analyzed; the emerging danger of obsolete computers by incorrect treatment was summarized; the integration disposal technologies based on 3R (recycle, remanufacture and reuse) engineering aiming at monitors, electronic devices, metals, plastics materials, and overall computers were put forward; the economic and social benefits were also analyzed. The results show that the integration disposal process of obsolete computer is an optimum approach to save the resource of electromechanical products. Remanufacturing and disposal 100 thousand obsolete computers per year can create profits about RMB10million yuan and provide employment for 300 persons. It can be deduced that there are great potential opportunities for the obsolete computers disposal industry containing recycle, remanufacture and reuse engineering.

云制造模式下的再制造企业生产调度研究

针对多重不确定因素影响下再制造企业如何高效合理进行再制造生产调度决策问题,提出了一种云制造模式下包含回收产品质量、再制造时间、再制造成本以及再制造处理方法等多种不确定因素的再制造生产调度模型。首先,对回收产品通过模糊层次聚类分析法进行质量等级划分;然后,根据划分结果采用不同的再制造处理方法;最后,通过NSGA-Ⅱ算法求解模型得到再制造生产调度方案。通过实验验证了该模型的可行性,并对比了进行质量划分与否对再制造生产过程中再制造时间和成本不确定的影响,结果表明进行质量等级划分能够有效减少再制造生产调度过程中再制造时间和加工成本不确定的影响。

电弧熔丝增材制造控形技术研究现状与展望

金属增材制造是制造强国战略下推动我国高端装备制造业转型升级的重点发展方向。电弧增材制造以其高沉积效率、低成本、可进行复杂结构直接成形等优势受到了广泛的关注。但增材过程中涉及的物理过程复杂,成形质量与精度面临很大挑战。针对电弧增材制造技术短流程、长周期的制造特征,讨论如何从热源上降低成形偏差、从过程上降低制造误差、从结果上改善成形精度,介绍了一系列创新的热源调制、过程控制与结果优化的方法策略,总结了现有技术存在的问题与面临的挑战,为如何进一步提升电弧增材过程的成形控制效果提出了几点思考。

基于偏正结构表示的加工命名实体识别方法

制造企业积累大量的零件加工经验多以文本形式存在,如何从文本中挖掘出高质量的零件加工知识是个尚待解决的问题。针对待识别实体存在的偏正结构特征,导致实体边界界定模糊的问题,提出一种多网络协调的中文命名实体识别方法。在BERT生成字向量的过程中,通过领域自适应方法,提高字向量对工艺实体的表征能力,同时,在BiLSTM-CRF模型中引入注意力机制和多门控制的混合专家网络捕获上下文特征与实体信息。实验表明,较于当前主流的命名实体识别模型,该文提出的方法对机械零件加工实体识别的F1值达到80.15%,取得优于其他模型的最好性能。

区块链赋能下的煤机装备供应链协同管理

随着我国煤炭开采工业技术的发展,煤机装备制造产业的诸多问题也暴露出来。针对传统模式下的煤机装备制造供应链各参与方所存在的信息孤岛、信息不对称与业务流转效率低等问题,提出了一种基于区块链技术的主从多链结构的煤机装备供应链信息管理平台,将供应链中的供应商、制造与再制造商、煤炭开采企业以及监管机构与金融机构相连接起来。设计了适用于煤机装备供应链的平台技术架构,搭建了模拟煤机装备供应链场景下的主从多链网络结构并测试了吞吐量与存储性能,探讨了区块链技术在煤机装备制造领域的实用优势,为煤机制造业与新一代信息技术的融合提供了新方向。

激光增材再制造修复技术的现状与发展趋势

激光增材再制造技术是基于激光熔覆、激光堆焊等激光沉积技术原理实现各种金属零部件损伤部位的几何尺寸或综合性能恢复的绿色制造新技术。针对激光增材再制造技术,具体阐述了增材再制造技术的国内外现状,并详细介绍了激光增材再制造的工艺类型以及在各行业的应用,最后展望了激光增材再制造技术的发展趋势。

混合进化算法求解多环节资源配置优化问题

资源配置优化问题是制造业价值链管理的基础问题。然而,现有研究多集中在生产环节,对制造全生命周期的整体考虑不足。研究考虑多环节的制造全生命周期资源配置优化问题(MLCRAOP),旨在通过优化研发设计、生产制造、运维服务和配套设备供应环节的服务资源,提升全生命周期的资源配置客户满意度。将时间、成本、质量指标纳入目标函数构建整数规划模型,提出一种混合进化算法用于求解MLCRAOP。通过在设计案例上的对比实验,验证了混合进化算法具有优异的性能。

高强铝合金电弧增材制造的研究进展

高强铝合金因具有高强度、低密度、优异的延展性和抗腐蚀性,成为了航空航天和汽车应用零件最常用的金属材料之一。电弧增材制造技术具有快速原位成形制造复杂结构零部件的能力,非常适用于中型或大型高强铝合金铝部件的制造。本文综合分析了高强铝合金电弧增材制造工艺和设备研发现状、高强铝合金电弧增材的固有属性和缺陷以及主要的性能优化手段,讨论了组织和性能的固有特征和复合增材制造技术对组织和性能的影响。针对电弧增材制造高强铝合金不可忽略的本质冶金缺陷、特征性能需求和多种优化工艺的优劣等问题,提出了电弧增材制造高强铝合金综合评价体系、成分设计和丝材开发、专用热处理制度和复合增材制造技术的协同性等发展方向,以期为电弧增材制造高强铝合金的性能提升和应用推广提供重要参考。

金属增材制造质量控制及复合制造技术研究现状

相比传统制造工艺,增材制造能够实现复杂结构金属部件的近净成形。然而,增材制造具有冷却速度快、热梯度大、非平衡凝固与往复热循环历史等特点,容易存在孔洞、残余拉应力、各向异性等缺陷,极大限制增材制造的进一步应用。复合增材制造技术是将传统制造方法与增材制造有机结合,充分发挥传统制造工艺在性能调控与尺寸精度等方面的优势,抑制单纯增材制造引起的各类缺陷,获得高质量、无缺陷的增材制造部件。本文首先揭示增材制造工艺缺陷的形成机理,明确工艺参数优化方法在缺陷改善方面的局限性,进而阐明复合增材制造的内涵,综述近年来增材制造与轧制、激光冲击强化、热等静压、热处理等复合制造技术的研究现状与工艺原理,探讨复合增材制造技术对不同缺陷的适用性,并对增材制造未来发展方向进行了展望。

用于星载高功率电子设备的增材制造平板热管设计与验证

针对未来星载高功率电子设备大功率、高热流、高集成的散热需求,解决传统槽道或丝网毛细芯平板热管逆重力传热量小、极限热流密度低的问题,文章提出了一种基于增材制造技术的新型平板热管,利用增材制造技术在成型复杂构型方面的优点,设计出一种基于复合毛细芯的平板热管构型,采用扫描电子显微镜(SEM)和显微断层扫描(MicroCT)对毛细芯微结构进行分析,结果表明:毛细芯结构成型完整、孔隙分布均匀。传热性能试验结果显示:二维平板热管极限热流密度高达88 W/cm~2,传热热阻仅为0.024℃/W,三维平板热管在不同姿态下传热能力和传热热阻变化显著,相关数据可为星载高功率电子设备热控设计和验证提供参考。