How will the diffusion of additive manufacturing impact the raw material supply chain process?

This study investigates the potential of additive manufacturing (i.e. 3D printing) to alter established manufacturing and supply chain processes, complementing previous research work that deals with additive manufacturing and rapid prototyping. Additive manufacturing is a manufacturing technique, which allows the direct fabrication of three-dimensional design models using an additive approach by adding layer after layer. As additive manufacturing is inherently less wasteful and only applies raw material where needed, it constitutes a chance to reduce materials usage and related inventories. Even though the technology has faced considerable hype, its adoption still does not match the high expectations. The aim of this study is to overcome limitations of state-of-the-art impact assessments by integrating the potential reduction of materials inventories through the adoption of additive manufacturing in manufacturing and to point out possible implications for supply chain processes. For this purpose, a dynamic evaluation model was developed analysing the adoption of additive manufacturing by integrating the Bass Diffusion Model to provide interesting and novel results for both practitioners and researchers. The study shows that additive manufacturing can indeed reduce raw materials inventory by approximately 4% and that the diffusion rate is likely to be affected by the utility of the technology.     

A digital process for additive manufacturing of occlusal splints: a clinical pilot study

The aim of this study was to develop and evaluate a digital process for manufacturing of occlusal splints. An alginate impression was taken from the upper and lower jaws of a patient with temporomandibular disorder owing to cross bite and wear of the teeth, and then digitized using a table laser scanner. The scanned model was repaired using the 3Data Expert software, and a splint was designed with the Viscam RP software. A splint was manufactured from a biocompatible liquid photopolymer by stereolithography. The system employed in the process was SLA 350. The splint was worn nightly for six months. The patient adapted to the splint well and found it comfortable to use. The splint relieved tension in the patient''s bite muscles. No sign of tooth wear or significant splint wear was detected after six months of testing. Modern digital technology enables us to manufacture clinically functional occlusal splints, which might reduce costs, dental technician working time and chair-side time. Maximum-dimensional errors of approximately 1 mm were found at thin walls and sharp corners of the splint when compared with the digital model.     

Informing additive manufacturing technology adoption: total cost and the impact of capacity utilisation

Informing Additive Manufacturing (AM) technology adoption decisions, this paper investigates the relationship between build volume capacity utilisation and efficient technology operation in an inter-process comparison of the costs of manufacturing a complex component used in the packaging industry. Confronting the reported costs of a conventional machining and welding pathway with an estimator of the costs incurred through an AM route utilising Direct Metal Laser Sintering (DMLS), we weave together four aspects: optimised capacity utilisation, ancillary process steps, the effect of build failure and design adaptation. Recognising that AM users can fill unused machine capacity with other, potentially unrelated, geometries, we posit a characteristic of ‘fungible’ build capacity. This aspect is integrated in the cost estimation framework through computational build volume packing, drawing on a basket of sample geometries. We show that the unit cost in mixed builds at full capacity is lower than in builds limited to a single type of geometry; in our study, this results in a mean unit cost overstatement of 157%. The estimated manufacturing cost savings from AM adoption range from 36 to 46%. Additionally, we indicate that operating cost savings resulting from design adaptation are likely to far outweigh the manufacturing cost advantage.     

Additive manufacturing technology in spare parts supply chain: a comparative study

Additive Manufacturing (AM) technology has the potential to significantly improve supply chain dynamics. The purpose of this paper is to investigate the impact of AM on spare parts supply chain. Three supply chain scenarios are investigated in this paper, namely conventional supply chain, centralised AM-based supply chain and distributed AM-based supply chain. Based on system dynamics simulations, this paper specifically compares three supply chain scenarios, in terms of total variable cost and carbon emission. The results show the spare part supply chain utilising AM is indeed superior to the traditional one in sustainable performance. It is also expected that AM can facilitate the spare parts supply chain to achieve more economic benefits along with its development. To our knowledge, this paper is one of the early studies that explores the impact of AM on supply chain performance and quantitatively examines the superiority of utilising AM in spare parts supply chain. Some suggestions are also provided to help managers adopting AM in their spare parts supply chains.     

Rapid additive manufacturing of functionally graded structures using simultaneous wire and powder laser deposition

Laser additive fabrication allows the manufacturing of functionally graded structures that are not possible using conventional subtractive manufacturing. Laser deposition of injected powders with varying compositions, layer-by-layer, is often used for the building up of functionally graded fully dense structures or materials. This approach, however, has some drawbacks: the un-used powders (normally 60-80%) cannot be recycled as they will be contaminated by the powder mixture. In addition, multiple passes are needed to develop functionally graded structures. This paper reports the feasibility and characteristics of using simultaneous powder and wire feeding laser deposition to produce functionally graded structures in a single step. This approach has been shown to eliminate the above problems associated with powder feed laser deposition. In this work, copper powder and nickel wire have been used to deposit functionally grated copper/nickel/iron structures on H13 tool steel. A 1.5-kW diode laser is used for the build-up process. Electron probe microanalysis (EPMA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and optical microscopy are used to analyse the deposited materials in terms of morphology, composition distributions, microstructures and phases formed. Successful deposition of functionally graded Cu-Ni-Fe structures has been demonstrated. Comparisons are made with the dual powder feed deposition process, which shows the inclusion of un-melted Ni powders in the Cu layer as a result of melting temperature difference of the two materials.     

Rapid additive manufacturing of functionally graded structures using simultaneous wire and powder laser deposition

Laser additive fabrication allows the manufacturing of functionally graded structures that are not possible using conventional subtractive manufacturing. Laser deposition of injected powders with varying compositions, layer-by-layer, is often used for the building up of functionally graded fully dense structures or materials. This approach, however, has some drawbacks: the un-used powders (normally 60–80%) cannot be recycled as they will be contaminated by the powder mixture. In addition, multiple passes are needed to develop functionally graded structures. This paper reports the feasibility and characteristics of using simultaneous powder and wire feeding laser deposition to produce functionally graded structures in a single step. This approach has been shown to eliminate the above problems associated with powder feed laser deposition. In this work, copper powder and nickel wire have been used to deposit functionally grated copper/nickel/iron structures on H13 tool steel. A 1.5-kW diode laser is used for the build-up process. Electron probe microanalysis (EPMA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and optical microscopy are used to analyse the deposited materials in terms of morphology, composition distributions, microstructures and phases formed. Successful deposition of functionally graded Cu–Ni–Fe structures has been demonstrated. Comparisons are made with the dual powder feed deposition process, which shows the inclusion of un-melted Ni powders in the Cu layer as a result of melting temperature difference of the two materials.     

The influence of additive manufacturing on the configuration of make-to-order spare parts supply chain under heterogeneous demand

Additive manufacturing (AM), alongside technological developments, has been used in the production of spare parts with positive results for spare parts supply chains. In this study, we investigate spare parts supply chains serving heterogeneous demands from multiple service locations under the mode of make-to-order. We aim to compare different configurations (i.e. centralised and distributed) of spare parts supply chains in terms of their performance (e.g. sojourn time and cost) and to further propose suggestions to better configure AM-based spare parts supply chains by effectively allocating AM machines at service locations (SLs) or regional distribution centres (RDCs). In order to realise these research objectives, the simulation approach is used as the main research method. Different from the existing perception, our results illustrate that the distributed deployment of AM machines does not always guarantee a quick response, and that centralised configuration is desirable when the demand rate is relatively high due to the pooling effect. The distributed configuration, however, can still be suitable, considering the development of AM technology. Our results also indicate the possibility of a mixed configuration of AM-based supply chains with the potential for outperforming the purely centralised/distributed configuration. The criteria to design such a mixed configuration are also offered.     

基于搅拌摩擦的金属固相增材制造研究进展EI北大核心CSCD

基于搅拌摩擦的固相增材制造是大型轻质合金构件成形制造的新技术,已成为国内外先进成形制造领域研究的热点之一。本文对目前国内外基于搅拌摩擦的金属固相增材制造技术及其相关工艺机理的研究现状进行了分析和总结。常见的基于搅拌摩擦的固相增材制造技术可分为三类:基于搅拌摩擦搭接焊原理,使板材逐层堆积,从而获得增材构件的搅拌摩擦增材制造(friction stir additive manufacturing,FSAM)技术;采用中空搅拌头,通过添加剂(粉末或丝材)进行固相搅拌摩擦沉积的增材制造(additive friction stir deposition,AFSD)技术;采用消耗型棒材,通过棒材的摩擦表面处理,形成增材层的摩擦表面沉积增材制造(friction surfacing deposition additive manufacturing,FSD-AM)技术。重点分析了金属材料基于搅拌摩擦的固相增材制造技术的国内外研究与应用现状,对比了三类基于搅拌摩擦的固相增材制造技术的特征及其工艺优缺点。最后指出增材工艺机理、形性协同控制、外场辅助工艺改型、新材料应用和人工智能优化是基于搅拌摩擦的固相增材制造技术未来研究的重点方向。     

The significance of organizational change management for sustainable competitiveness in manufacturing: exploring the firm archetypes

The successful development and deployment of adequate sustainable manufacturing strategies are still open issues and of utmost interest for research and practice. Guided by this particular challenge, we investigate the significance of organisational change management for sustainable competitiveness in manufacturing. By using six case studies from the Lombardia region in Italy and basing our research on the theoretical constructs of competitive aggressiveness and organisational change, we discover four archetypes of companies that show an increasing sustainable competitiveness with an increasing formalism and persistence in organisational change. Our findings suggest that change management practices are conditional hypothesis for creating competitive advantage through sustainability, and implementation gaps do hinder companies in realising the full potential. The study offers guidance to stakeholders, on how change management actions may potentially affect company performance in the manufacturing sector, as well as providing direction on the impact improved planning and leadership instances can have on the sustainability performance.     

Energy consumption model of Binder-jetting additive manufacturing processes

Considering the potential for new product design possibilities and the reduction of environmental impacts, Additive Manufacturing (AM) processes are considered to possess significant advantages for automotive, aerospace and medical equipment industries. One of the commercial AM techniques is Binder-jetting (BJ). This technique can be used to process a variety of materials including stainless steel, ceramic, polymer and glass. However, there is very limited research about this AM technology on energy consumption aspect. This paper presents a method to build an energy consumption model for printing stage of BJ process. Mathematical analyses are performed to find out the correlation between the energy consumption and geometry of the manufactured part. Based on the analyses, total energy consumption is calculated as a function of part geometry and printing parameters. Finally, test printing is performed to check the accuracy of the model. This process model provides a tool to optimise part geometry design with respect to energy consumption.     

光丝同轴激光增材制造研究进展

增材制造作为实现三维结构快速成形的技术,广泛用于航空航天、汽车交通等领域.当前,激光熔丝增材制造多依托于传统的激光焊接设备,采用旁轴送丝方式,在增材过程中,需调整激光头方向保证送丝和焊接头行进的相对方位,增大了复杂构件增材制造系统控制难度,损失了加工自由度.随着激光加工设备和技术的发展,近年来出现了一种可以解决上述问题...     

A quality management framework for implementing additive manufacturing of medical devices

This paper aims to provide a comprehensive review of the implementation of additive manufacturing (AM) for medical devices. A quality management framework is proposed with discussion on topics such as software and data input, product understanding, AM equipment qualification, process understanding and continuous process verification. The interplay between input materials, process controls, and final outcomes of AM were analysed in the framework of quality management. Opportunities and challenges in implementing AM for medical devices are discussed.     

Direct fabrication of single-crystal-like structure using quasi-continuous-wave laser additive manufacturing

The synchronously periodic re-melting of molten pool was firstly introduced in additive manufacturing to promote the epitaxial growth of columnar structure using a novel quasi-continuous-wave(QCW)laser.The epitaxial growth of columnar structure was intensified and the single-crystal-like sample with highly oriented "zigzag" columnar grains was produced.The modified molten-pool geometry and the synchronously high-frequency re-melting of the molten pool contribute to the formation of singlecrystal-like structure.This work reports a new route to promote the continuously epitaxial growth of dendrites for fabrication of single-crystal-like sample.     

An effective analytical model of selective laser melting

Selective Laser Melting (SLM) is a laser-based powder bed Additive Manufacturing process that can produce near net shape products with metallic powders according to Computer-Aided Design models. In this paper, a useful analytical model of SLM is proposed by investigating the energy requirement of the process. Results from the experiments on SLM of pure nickel and pure tin are reported. By compiling process parameter data from various literatures and experiments, this model has shown to enable predictions of the energy input required to process different metallic materials to an order of magnitude despite the many assumptions made. Possible explanations for the deviation in predictions and actual energy inputs are also discussed.     

The impact of supply chain analytics on operational performance: a resource-based view

This study seeks to better understand the role of supply chain analytics (SCA) on supply chain planning satisfaction and operational performance. We define the architecture of SCA as the integration of three sets of resources, data management resources (DMR), IT-enabled planning resources and performance management resources (PMR), from the perspective of a resource-based view. Based on the data collected from 537 manufacturing plants, we test hypotheses exploring the relationships among these resources, supply chain planning satisfaction, and operational performance. Our analysis supports that DMR should be considered a key building block of manufacturers’ business analytics initiatives for supply chains. The value of data is transmitted to outcome values through increasing supply chain planning and performance capabilities. Additionally, the deployment of advanced IT-enabled planning resources occurs after acquisition of DMR. Manufacturers with sophisticated planning technologies are likely to take advantage of data-driven processes and quality control practices. DMR are found to be a stronger predictor of PMR than IT planning resources. All three sets of resources are related to supply chain planning satisfaction and operational performance. The paper concludes by reviewing research limitations and suggesting further SCA research issues.     

An impact of manufacturing flexibility and technological dimensions of manufacturing strategy on improving supply chain responsiveness: Business environment perspective

The main objective of this research is to investigate the impact of manufacturing flexibility and technological dimensions of manufacturing strategy on responsiveness in the supply chain. Based on the theoretical background of dynamic capability, this study also examines the role of the business environment on the relationship between manufacturing flexibility and supply chain responsiveness. 144 structured surveys were collected and the partial least squares of structural equation modelling approach were utilised for data analysis. The result establishes relationships among various dimensions of manufacturing flexibility. Although the technological dimensions in manufacturing strategy of such advanced manufacturing technology (AMT) and e-procurement do not have any direct impact on new product and market flexibility, they increase supply chain responsiveness, which helps to react quickly against supply chain disruptions. More importantly, the business environment has a moderating effect on the relationship between market flexibility and supply chain responsiveness.     

Effects of microstructure on fatigue crack propagation behavior in a bi-modal TC11 titanium alloy fabricated via laser additive manufacturing

In this study, the crack propagation behaviors in the equiaxed and equiaxed-columnar grain regions of a heat-treated laser additive manufacturing (LAM) TC11 alloy with a special bi-modal microstructure are investigated. The results indicate that the alloy presents a special bi-modal microstructure that comprises a fork-like primary α (α_p) phase surrounded by a secondary α colony (α_s) in the β phase matrix after the heat treatment is completed. The samples demonstrate a fast crack growth rate with larger da/dN values through the equiaxed grain sample versus across the equiaxed-columnar grain sample at low ΔK values (<13.8). The differences that are observed between the crack propagation behaviors (in the crack initiation stage) of the samples can be mostly attributed to the different size and morphology of the α_p lamellae and α_s colony within the grains in the equiaxed and columnar grain regions rather than the grain boundaries. The cracks prefer to grow along the α/β boundary with a smooth propagation route and a fast propagation rate in the equiaxed grain region, where the α_p and α clusters have a large size. However, in the columnar grain region, small and randomly distributed α_p lamellae generate a zigzag-shaped propagation path with a reduction in the da/dN value. Additionally, the change in the size of the α_p lamellae in the equiaxed grains (heat affected bands, HAB) is also observed to influence the propagation behavior of the crack during the crack initiation stage.     

增材制造Ti-6Al-4V钛合金低周疲劳性能研究进展

金属增材制造技术可用于大型、复杂高性能钛合金结构件的制备,在航空航天等领域具有显著的优势和巨大的发展潜力。虽然增材制造Ti-6Al-4V合金构件的强度已经能够超过锻件,但它仍存在内部孔隙、熔合不良、粗大的柱状晶及残余拉应力等问题,使其在疲劳性能上与锻件具有一定的差距。本文在介绍直接能量沉积、选区激光熔化和电子束选区熔化3种代表性增材制造技术的原理及特点的基础上,简述了3种工艺制备Ti-6Al-4V合金构件的微观组织、静态力学性能及低周疲劳性能的研究进展,重点讨论了打印方向、缺陷、显微组织和表面处理对低周疲劳性能的影响。分析了增材制造Ti-6Al-4V合金构件低周疲劳性能、拉伸性能与微观组织之间的内在关系,并对提高构件低周疲劳性能的方法和推动其广泛应用的发展方向进行展望。     

Selective laser melting of novel nanocomposites parts with enhanced tribological performance

Selective laser melting (SLM) was applied to build the nanocrystalline TiC/Ti nanocomposites parts. The influence of linear laser energy density (λ) on densification, microstructures, microhardness, and tribological performance of SLM-processed parts was investigated. It showed that the densification rate of TiC/Ti parts remained above 97% using linear laser energy density λ≥600 J/m. A decrease in λ caused the balling effect and lowered densification. The TiC reinforcement in SLM-processed parts had unique microstructures distinctly different from the initial nanoparticle morphology. A proper decrease in λ led to the formation of the uniformly dispersed nanoscale lamellar TiC reinforcement. The SLM-processed parts had an enhanced microhardness of 566 HV_0.2, a low average coefficient of friction (COF) of ~0.25 and a reduced wear rate of ~4×10^?16 m³/(Nm) during dry sliding tests. The insufficient SLM densification at a low λ and the disappearance of nanoscale TiC reinforcement at a high λ generally lowered the tribological performance of SLM-processed TiC/Ti parts.     

The impact of supply chain relationships and integration on innovative capabilities and manufacturing performance: the perspective of rapidly developing countries

The purpose of this research is to investigate the relationships between supply chain relationships/integration, innovative capabilities and manufacturing performance. The study adopts Institutional Theory and Resource-Based View Theory to assess relationships in 171 organisations drawn from three rapidly developing countries – Brazil, India and China. Data were collected using the International Manufacturing Strategy Survey (IMSS VI) and analysed using structural equation modelling. The study found that supply chain relationships and integration relate positively to both product and process innovative capabilities. The study also found that both product and process innovative capabilities relate positively to manufacturing performance. Furthermore, there was a positive relationship between product innovative capabilities and process innovative capabilities. The findings provide new insights into manufacturers in the three countries and show that the relationships they build with their customers have encouraged them to develop new innovative capabilities. These new capabilities, in turn, have enabled them to reap benefits of improved manufacturing performance.