Search results

We consider a joint optimization problem of product platform design and scheduling on unrelated additive/subtractive hybrid machines, and seek to find efficient solution approaches to solve such problem.

We propose a mathematical formulation for the problem of simultaneous product platform design and scheduling on unrelated additive/subtractive hybrid machines, and develop a simulated annealing-based hyper-heuristic algorithm with adjustable operator sequence length to solve the problem.

The simulated annealing-based hyper-heuristic algorithm with adjustable operator sequence length (SAHH-osla) that we proposed can be quite efficient in solving the problem of simultaneous product platform design and scheduling on unrelated additive/subtractive hybrid machines.

To the best of our knowledge, we are one of the first to consider both cost-related and time-related criteria for the problem of simultaneous product platform design and scheduling on unrelated additive/subtractive hybrid machines.

As an advanced manufacturing method, additive manufacturing (AM) technology provides new possibilities for efficient production and design of parts. However, with the continuous expansion of the application of AM materials, subtractive processing has become one of the necessary steps to improve the accuracy and performance of parts. In this paper, the processing process of AM materials is discussed in depth, and the surface integrity problem caused by it is discussed.

Firstly, we listed and analyzed the characterization parameters of metal surface integrity and its influence on the performance of parts and then introduced the application of integrated processing of metal adding and subtracting materials and the influence of different processing forms on the surface integrity of parts. The surface of the trial-cut material is detected and analyzed, and the surface of the integrated processing of adding and subtracting materials is compared with that of the pure processing of reducing materials, so that the corresponding conclusions are obtained.

In this process, we also found some surface integrity problems, such as knife marks, residual stress and thermal effects. These problems may have a potential negative impact on the performance of the final parts. In processing, we can try to use other integrated processing technologies of adding and subtracting materials, try to combine various integrated processing technologies of adding and subtracting materials, or consider exploring more efficient AM technology to improve processing efficiency. We can also consider adopting production process optimization measures to reduce the processing cost of adding and subtracting materials.

With the gradual improvement of the requirements for the surface quality of parts in the production process and the in-depth implementation of sustainable manufacturing, the demand for integrated processing of metal addition and subtraction materials is likely to continue to grow in the future. By deeply understanding and studying the problems of material reduction and surface integrity of AM materials, we can better meet the challenges in the manufacturing process and improve the quality and performance of parts. This research is very important for promoting the development of manufacturing technology and achieving success in practical application.

The purpose of this paper is to present an algorithm for an additive/subtractive rapid pattern manufacturing (RPM) process where thick slabs of material are sequentially stacked and then cut to 3D shapes. Unlike traditional rapid prototyping processes where layer thickness is typically uniform, this process is able to vary the layer thickness in order to most effectively generate feature shapes.

This paper discusses the factors affecting layer thickness decisions and then presents an algorithm to determine layer thicknesses for a given part model. The system is designed to import a computer‐aided design file and use the algorithm to automatically generate the set of layers based on the slab height, material and bonding properties and the process parameters used in the system.

The layer thickness algorithm is implemented and tested using an additive/subtractive manufacturing system developed in the laboratory. The algorithm has proved effective in determining appropriate layer heights for thick slab machining, taking into account a variety of geometries. Several sand casting patterns have been successfully created using the proposed system, which could significantly improve traditional sand casting pattern manufacturing.

The proposed RPM process is a new process presented by the authors, developed for rapid sand castings. The layer thickness algorithm is an original contribution that enables automatic process planning for this new process.

The purpose of this paper is to develop a hybrid additive/subtractive manufacturing platform for the production of high density ceramic components.

Fabrication of near-net shape components is achieved using 96 per cent Al3O2 ceramic paste extrusion and a planarizing machining operations. Sacrificial polymer support can be used to aid the creation of overhanging or internal features. Post-processing using a variety of machining operations improves tolerances and fidelity between the component and CAD model while reducing defects.

This resultant three-dimensional monolithic ceramic components demonstrated post sintering tolerances of ±100 µm, surface roughness’s of ∼1 µm Ra, densities in excess of 99.7 per cent and three-point bending strength of 221 MPa.

This method represents a novel approach for the digital fabrication of ceramic components, which provides improved manufacturing tolerances, part quality and capability over existing additive manufacturing approaches.

To remanufacture a disused part, a hybrid process needs to be taken in part production. Therefore, a reasonable machining route is necessary to be developed for the hybrid process. This paper aims to develop a novel process planning algorithm for additive and subtractive manufacturing (ASM) system to achieve this purpose.

First, a skeleton of the model is generated by using thinning algorithm. Then, the skeleton tree is constructed based on topological structure and shape feature. Further, a feature matching algorithm is developed for recognizing the different features between the initial model and the final model based on the skeleton tree. Finally, a reasonable hybrid machining route of the ASM system is generated in consideration of the machining method of each different sub-feature.

This paper proposes a hybrid process planning algorithm for the ASM system. Further, it generates new process planning insights on the hybrid process service provider market.

The proposed process planning algorithm enables engineers to obtain a proper hybrid machining route before product fabrication. And thereby, it extends the machining capability of the hybrid process to manufacture some parts accurately and efficiently.

This study addresses one gap in the hybrid process literature. It develops the first hybrid process planning strategy for remanufacturing of disused parts based on skeleton tree matching, which generates a more proper hybrid machining route than the currently available hybrid strategy studies. Also, this study provides technical support for the ASM system to repair damaged parts.

This paper aims to present a friction stir molding (FSM) method for the rapid manufacturing of metal tooling. The method uses additive and subtractive techniques to sequentially friction stir bond and then mill slabs of metal. Mold tooling is grown in a bottom-up fashion, overcoming machining accessibility problems typically associated with deep cavity tooling.

To test the feasibility of FSM in building functional molds, a layer addition procedure that combines friction stir spot welding (FSSW) with an initial glue application and clamping for slabs of AA6061-T651 was investigated. Additionally, FSSW parameters and the mechanical behavior of test mold materials, including shear strength and hardness, were studied. Further, scanning electron microscopy (SEM)/elemental map analysis (EDS) of the spot weld zones was carried out to understand the effect of FSSW on the glue materials and to study potential mixing of glue with the plate materials in the welded zone.

The results indicate that FSM provides good layer stacking without gaps when slabs are pre-processed through sand blasting, moistening, uniform clamping and FSSW using a tapered pin tool. The tensile shear strength results revealed that the welded spots were able to withstand cutting forces during machining stages; however, FSSW was found to cause hardness reduction among spot zones because of over-aging. The SEM/EDS results showed that glue was not mixed with slab materials in spot zones. The proposed process was able to build a test tooling sample successfully using AA6061-T651 plates welded and machined on a three-axis computer numerical control (CNC) mill.

The proposed FSM process is a new process presented by the authors, developed for the rapid manufacturing of metal tooling. The method uses additive and subtractive techniques to sequentially friction stir bond and then mill slabs of metal. The use of FSSW process for materials addition is an original contribution that enables automatic process planning for this new process.

The purpose of this paper is to study the introduction of 3D-printing of concrete in the construction sector.

A survey was conducted to collect professional view on ongoing innovations in the construction sector, including 3D-printing. Participants were selected among the members of Norwegian networks for project and construction management research.

The survey highlighted effective leadership, collaboration with partners and industry-academia collaboration as primary enablers of innovation. Few of the respondents to the survey have used 3D-printing technologies.

It is difficult to obtain representative samples in this type of research, including this study. The study can be seen as a snapshot of attitudes in the sector.

3D-printing appear as a potentially interesting technology, especially for unstandardized construction components. Further work is needed to materialise the expectation for technological development in the construction sector.

Most research on 3D-printing has focused on demonstrating technical potential. This study adds a practitioners’ perspective, with a large dose of pragmatism.

The purpose of this paper is to present a new method for automated post machining process planning for a hybrid manufacturing process. The manufacturing process is expected to generate complex functional parts by taking advantage of free form surface creation from additive manufacturing and high-quality surface finishing from CNC milling.

The hybrid process starts with additive manufacturing to generate a near net shape part with pre-defined machining allowances on surfaces requiring high quality surface or tight tolerances, along with integrated fixture geometry. The next step is to conduct automated machining process planning to determine critical parameters such as setup angle, tool selection, depth, tool containment, and consequently, the NC code to machine the part.

This method is shown to be a feasible solution for rapidly creating functional parts. The tests have been conducted to validate the method developed in this paper.

This paper introduces a new automated post machining process planning method for integrating additive manufacturing with a rapid milling process.

The purpose of this paper is to report the state of art review on sustainable additive manufacturing (AM).

AM processes are becoming environmentally conscious and sustainable. In total, 63 papers are being collected from peer-reviewed journal sources. The review is presented on triple bottom line sustainable aspects, namely, environment, economy and society.

In the environmental dimension, papers on energy consumption, design optimization and life cycle assessment aspects are being collected and presented. The key inferences and insights are being derived from the mentioned perspectives and a framework for sustainable AM is proposed.

The review is limited to journal articles from the study on sustainable AM. Book chapters are being excluded.

The study also discussed various perspectives of sustainable AM and provided insights on sustainable AM to practitioners.

Systematic review on sustainable additive manufacturing is the original contribution of the authors.

The purpose of this study is to highlight the direct fabrication of rapid tooling (RT) with desired mechanical, tribological and thermal properties using fused deposition modelling (FDM) process. Further, the review paper demonstrated development procedure of alternative feedstock filament of low-cost composite material for FDM to extend the range of RT applications.

The alternative materials for FDM and their processing requirements for fabrication in filament form as reported by various researchers have been summarized. The literature demonstrates the role of various post-processing techniques on surface finish of FDM prints. Further, low-cost materials for feedstock filament have been investigated experimentally to check their adaptability/suitability for commercial FDM setup. The approach was to realize the requirements of FDM (melt flow rate, flexibility, stiffness, glass transition temperature and mechanical strength), necessary for the successful run of an alternative filament. The effect of constituents (additives, plasticizers, surfactants and fillers) in polymeric matrix on mechanical, tribological and thermal properties has been investigated.

It is possible to develop composite material feedstock as filament for commercial FDM setup without changing its hardware and software. Surface finish of the parts can further be improved by applying various post-processing techniques. Most of the composite parts have high mechanical strength, hardness, thermal stability, wear resistant and better bond formation than standard material parts.

Future research may be focused on improving the surface quality of parts fabricated with composite feedstock, solving issues related to the uniform distribution of filled materials during the fabrication of feedstock filament which in turns further increases mechanical strength, high dimensional stability of composite filament and transferring the technology from laboratory scale to various industrial applications.

Potential applications of direct fabrication with RT includes rapid manufacturing (RM) of metal-filled parts and ceramic-filled parts (which have complex shape and cannot be rapidly made by any other manufacturing techniques) in the field of biomedical and dentistry.

This new manufacturing methodology is based on the proper selection and processing of various materials and additives to form high-performance, low-cost composite material feedstock filament (which fulfil the necessary requirements of FDM process). Finally, newly developed feedstock filament material has both quantitative and qualitative advantage in RT and RM applications as compared to standard material filament.