Search results

1 – 10 of 485
To view the access options for this content please click here
Article
Publication date: 18 January 2016

Marlon Wesley Machado Cunico and Jonas de Carvalho

The purpose of this study is to present a novel additive manufacturing (AM) technology which is based on selective formation of cellulose-acrylate composite. Besides…

Abstract

Purpose

The purpose of this study is to present a novel additive manufacturing (AM) technology which is based on selective formation of cellulose-acrylate composite. Besides proposing a process that combines the benefits of fibres and photopolymers, this paper reports the development of material, characterisation of a straight line composite formation, adherence between layers and functional feasibility of the proposed concept.

Design/methodology/approach

For the preliminary evaluation of the proposed process, a composite material based on cellulose-photopolymer was developed, while a multi-objective optimisation study indicated the formulation which results in the maximum values of layer adherence, tensile strength of composite and the effect of the water on the mechanical strength of material. For the characterisation of the process, three main subjects were analysed: the characterisation of straight line composite formation, the effect of composite formation process on previous layers and the functional feasibility of technology.

Findings

In the material development, the tensile strength of dry composite was identified between 20 and 30 MPa, while the tensile strength of wet composite was between 5 and 12 MPa. It is important to note that the dry and wet cellulose presented tensile strength, respectively, equal to 15 and 1 MPa, indicating the possibility of residual material removal only with the use of water or other soft solvent. The values of adherence between layers (peeling test) were found to be between 0.12 and 0.15 kgf, and the photopolymer formulation which resulted in the maximum adherence has monomer/oligomer ratio equal to 1.5 and 2 per cent wt of photoinitiator percentual. As result of the optimisation study, the material formulation was compounded by monomer – 10 ml, oligomer – 4.5 ml and photoinitiator – 2 per cent, being found suitable to characterise and evaluate the proposed process. The study of composite formation along a straight line showed values of line width between 1,400 and 3,500 μm in accordance with light power, laser velocity and laser beam diameter. On the other hand, the number of previous layers affected by the composite formation varied from 0 to 4, indicating a potential process limit. In the functional feasibility study, a feasible process window which resulted in the maximum dimensional deviation equal to 0.5 mm was identified. In addition, the mean mechanical tensile strength was found to be around 30 MPa for longitudinal laser trajectory (90°) and 15 MPa for transversal laser trajectory (0°), highlighting the anisotropic behaviour of final parts according to the manufacturing strategy.

Originality/value

This paper proposed a novel AM technology and also described studies related to the characterisation of this concept. This work might also be useful to the development of other AM processes and applications.

To view the access options for this content please click here
Article
Publication date: 2 January 2018

Marlon Wesley Machado Cunico and Jonas de Carvalho

During the past years, numerous market segments have increasingly adopted additive manufacturing technologies for product development and complex parts design…

Abstract

Purpose

During the past years, numerous market segments have increasingly adopted additive manufacturing technologies for product development and complex parts design. Consequently, recent developments have expanded the technologies, materials and applications in support of emerging needs, in addition to improving current processes. The present work aims to propose and characterise a new technology that is based on selective formation of metal-polymer composites with low power source.

Design/methodology/approach

To develop this project, the authors have divided this work in three parts: material development, process feasibility and process optimisation. For the polymeric material development, investigation of metallic and composite materials assessed each material’s suitability for selective composite formation besides residual material removal. The primary focus was the evaluation of proposed process feasibility. The authors applied multivariable methods, where the main responses were line width, penetration depth, residual material removal feasibility, layer adherence strength, mechanical strength and dimensional deviation of resultant object. The laser trace speed, distance between formation lines and laser diameter were the main variables. Removal agent and polymeric material formulation were constants. In the last part of this work, the authors applied a multi-objective optimisation. The optimisation objectives minimized processing time and dimensional deviation while maximizing mechanical strength in xy direction and mechanical strength in z direction.

Findings

With respect to material development, the polymeric material tensile strength was found between 30 and 45 MPa at break. It was also seen that this material has low viscosity before polymerized (between 2 and 20 cP) essential for composite formation and complete material removal. In that way, the authors also identified that the residual material removal process was possible by redox reaction. In contrast with that the final object was marked by the polymer which covers the metallic matrix, protecting the object protects against chemical reactions. For the feasibility study, the authors identified the process windows for adherence between composite layers, demonstrating the process feasibility. The composite mechanical strength was shown to be between 120 and 135 MPa in xy direction and between 35 and 45 MPa in z direction. In addition, the authors have also evidenced that the geometrical dimensional distortion might vary until 5 mm, depending on process configuration. Despite that, the authors identified an optimised configuration that exposes the potential application of this new technology. As this work is still in a preliminary development stage, further studies are needed to be done to better understand the process and market segments wherein it might be applied.

Originality/value

This paper proposed a new and innovative additive manufacturing technology which is based on metal-polymer composites using low power source. Additionally, this work also described studies related to the investigation of concept feasibility and proposed process characterisation. The authors have focused on material development and studied the functional feasibility, which at the same time might be useful to the development of other additive manufacturing processes.

Details

Rapid Prototyping Journal, vol. 24 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 7 August 2007

J. Vasco, P. J. Bártolo, B. Silva and C. Galo

Laser milling is a non‐conventional layer‐by‐layer material removal technology suitable for machining a wide range of materials. This technology is particularly suitable…

Abstract

Purpose

Laser milling is a non‐conventional layer‐by‐layer material removal technology suitable for machining a wide range of materials. This technology is particularly suitable to produce microstructures inside cavities, also obtained by other conventional processes, though with larger material removal rates, or for the direct development of microcavities not requiring high removal rates. This paper seeks to evaluate the capacity of laser milling for manufacturing of mould inserts.

Design/methodology/approach

The paper examined several specific features of laser milling, important for the manufacturing of mould inserts, such as walls verticality, unselected illuminating areas, due to an incorrect STL removal volume definition, aspiration process and orientation, to prevent welding of re‐solidified particles on the surface. Two mould inserts were produced too, assembled on a metallic mould frame and tested with different injection conditions.

Findings

The findings suggest that laser milling is a suitable technology to produce small mould insert for injection moulding, though injection conditions are different as one moves from macroscopic to microscopic injected parts. New design guidelines must be undertaken jointly with the assessment of laser milling performance to make mould microcavities. One of the major difficulties of this process is to keep the side walls vertical plus the generation of undesirable machined volumes, due to unselected illuminating areas below the STL volume, corresponding to the volume to be removed, whenever laser milling is used to operate with structures previously machined. To prevent welding of re‐solidified particles on the surface a proper aspiration must also be considered.

Originality/value

The paper describes the benefits of laser milling technology.

Details

Assembly Automation, vol. 27 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

To view the access options for this content please click here
Article
Publication date: 20 November 2020

S. Madhu and M. Balasubramanian

The purpose of this study is for solving many issues in production that includes processing of complex-shaped profile, machining of high-strength materials, good surface…

Abstract

Purpose

The purpose of this study is for solving many issues in production that includes processing of complex-shaped profile, machining of high-strength materials, good surface finish with high-level precision and minimization of waste. Among the various advanced machining processes, abrasive jet machining (AJM) is one of the non-traditional machining techniques used for various applications such as polishing, deburring and hole making. Hence, an overview of the investigations done on carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GRFP) composites becomes important.

Design/methodology/approach

Discussion on various approaches to AJM, the effect of process parameters on the glass fiber and carbon fiber polymeric composites are presented. Kerf characteristics, surface roughness and various nozzle design were also discussed.

Findings

It was observed that abrasive jet pressure, stand-off distance, traverse rate, abrasive size, nozzle diameter, angle of attack are the significant process parameters which affect the machining time, material removal rate, top kerf, bottom kerf and kerf angle. When the particle size is maximum, the increased kinetic energy of the particle improves the penetration depth on the CFRP surface. As the abrasive jet pressure is increased, the cutting process is enabled without severe jet deflection which in turn minimizes the waviness pattern, resulting in a decrease of the surface roughness.

Research limitations/implications

The review is limited to glass fiber and carbon fiber polymeric composites.

Practical implications

In many applications, the use of composite has gained wide acceptance. Hence, machining of the composite need for the study also has gained wide acceptance.

Social implications

The usage of composites reduces the usage of very costly materials of high density. The cost of the material also comes down.

Originality/value

This paper is a comprehensive review of machining composite with abrasive jet. The paper covers in detail about machining of only GFRP and CFRP composites with various nozzle designs, unlike many studies which has focused widely on general AJM of various materials.

Details

World Journal of Engineering, vol. 18 no. 2
Type: Research Article
ISSN: 1708-5284

Keywords

To view the access options for this content please click here
Article
Publication date: 25 September 2009

Frances D. Bryant and Ming C. Leu

The purpose of this paper is to develop a physics‐based model that can predict how a main build material of water interacts with a water‐soluble sacrificial support…

Abstract

Purpose

The purpose of this paper is to develop a physics‐based model that can predict how a main build material of water interacts with a water‐soluble sacrificial support material in the rapid freeze prototyping (RFP) process.

Design/methodology/approach

RFP uses water freezing into ice in a layer‐by‐layer manner as a main build material to create ice structures with complex geometries in a sufficiently cool environment. A eutectic dextrose‐water solution is used as a sacrificial support material. The supported areas in an ice structure are removed by placing the fabricated structure in an environment of appropriate temperature.

Findings

Two methods of concentration modeling have been developed to predict the interaction between the main and support materials around their interface region. The two models are described in detail and their predictions are compared to experimentally measured data. The experimental height data compared to the simulation result based on the concentration models agrees to within 6 percent for various build ambient temperatures. As ambient temperatures decreased, diffusion between the two materials also decreased.

Originality/value

The results obtained from this paper can be used as an aid in building complex ice parts in the RFP process so that minimal interaction between the main and support materials can be attained. An understanding of the interaction occurring during fabrication is provided with the concentration models. The method used to develop the concentration models can be applied to other layered manufacturing processes when using two miscible materials.

Details

Rapid Prototyping Journal, vol. 15 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 18 November 2013

Xiaohu Zheng, Dapeng Dong, Lixin Huang, Xibin Wang and Ming Chen

– The paper aims to investigate tool wear mechanism and tool geometry optimization of drilling PCB fixture hole.

Abstract

Purpose

The paper aims to investigate tool wear mechanism and tool geometry optimization of drilling PCB fixture hole.

Design/methodology/approach

An experimental study was carried out to investigate the chip formation and tool wear mechanism of drilling PCB fixture holes. Two types of drill with different types of chip-split groove were used in this study. The performances of these two types of drill bots were evaluated by tool wear and the shapes of chips.

Findings

The chips of drilling fixture holes contain aluminum chips from the cover board, copper chips from the copper foil, discontinuous glass fiber and resin from the CFRP. Feed rate and drilling speed have a great influence on the chip morphology. Abrasive wear of the drill lip is the main reason of the fixture drill bit in drilling PCB, and micro-chipping is observed on the tool nose and chisel edge. The influence of distance between the chip-split groove and drill point center on the axial force and torque is not obvious.

Research limitations/implications

In this paper, hole wall roughness and drilling temperature were not analyzed in the optimization of drilling parameters. The future research work should consider them.

Originality/value

This paper investigated the mechanism of burr formation and tool wear in drilling of PCB fixture holes. Tool geometry was optimized by adding chip-split grooves.

Details

Circuit World, vol. 39 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

To view the access options for this content please click here
Article
Publication date: 10 October 2018

Niechen Chen, Prashant Barnawal and Matthew Charles Frank

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…

Abstract

Purpose

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.

Design/methodology/approach

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.

Findings

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.

Originality/value

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

Details

Rapid Prototyping Journal, vol. 24 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 4 September 2009

Manocher Djassemi

The purpose of this paper is to provide a perspective of computer‐aided material and process selection (MPS) software tools for product development purpose and present a…

Abstract

Purpose

The purpose of this paper is to provide a perspective of computer‐aided material and process selection (MPS) software tools for product development purpose and present a practical approach for manufacturers and other decision makers involved in MPS.

Design/methodology/approach

A multi‐criteria deductive approach for MPS is applied to a case study by taking into account the technical performances and environmental constraints. A resource‐based cost modeling is also deployed to examine the implication of selected material and process on overall product cost.

Findings

The paper demonstrates the capabilities and shortcoming of existing computerized MPS software tools in assisting product managers and designers for handling the growing volume of material/process data.

Research limitations/implications

Applying computer‐aided MPS approach to complex shape products with multiple features is not a straightforward task and requires further development in existing MPS software tools.

Practical implications

Computer‐aided MPS systems can assist decision makers in solving many material/process selection problems by following a systematic process.

Originality/value

Given today's rapid technological changes, it is important for decision makers to understand the capabilities of computer‐aided MPS software tools in handling a growing volume of data. Very limited research has been done to explore the capabilities and limitations of existing material/process selectors. It is the first in the literature that demonstrates the application of multi‐criteria deductive approach in MPS using a software tool.

Details

Journal of Manufacturing Technology Management, vol. 20 no. 7
Type: Research Article
ISSN: 1741-038X

Keywords

To view the access options for this content please click here
Article
Publication date: 20 October 2014

Karel Kellens, Renaldi Renaldi, Wim Dewulf, Jean-pierre Kruth and Joost R. Duflou

This paper aims to present parametric models to estimate the environmental footprint of the selective laser sintering (SLS)’ production phase, covering energy and resource…

Abstract

Purpose

This paper aims to present parametric models to estimate the environmental footprint of the selective laser sintering (SLS)’ production phase, covering energy and resource consumption as well as process emissions. Additive manufacturing processes such as (SLS) are often considered to be more sustainable then conventional manufacturing methods. However, quantitative analyses of the environmental impact of these processes are still limited and mainly focus on energy consumption.

Design/methodology/approach

The required Life Cycle Inventory data are collected using the CO2PE! – Methodology, including time, power, consumables and emission studies. Multiple linear regression analyses have been applied to investigate the interrelationships between product design features on the one hand and production time (energy and resource consumption) on the other hand.

Findings

The proposed parametric process models provide accurate estimations of the environmental footprint of SLS processes based on two design features, build height and volume, and help to identify and quantify measures for significant impact reduction of both involved products and the supporting machine tools.

Practical implications

The gained environmental insight can be used as input for ecodesign activities, as well as environmental comparison of alternative manufacturing process plans.

Originality/value

This article aims to overcome the current lack of environmental impact models, covering energy and resource consumption as well as process emissions for SLS processes.

To view the access options for this content please click here
Article
Publication date: 4 February 2014

De-Xing Peng

Chemical mechanical polishing (CMP) has attracted much attention recently because of its importance as a nano-scale finishing process for high value-added large components…

Abstract

Purpose

Chemical mechanical polishing (CMP) has attracted much attention recently because of its importance as a nano-scale finishing process for high value-added large components that are used in the aerospace industry. The paper aims to discuss these issues.

Design/methodology/approach

The characteristics of aluminum nanoparticles slurry including oxidizer, oxidizer contents, abrasive contents, slurry flow rate, and polishing time on aluminum nanoparticles CMP performance, including material removal amount and surface morphology were studied.

Findings

Experimental results indicate that the CMP performance depends strongly on the oxidizer, oxidizer contents, and abrasive contents. Surface polished by slurries that contain nano-Al abrasives had a lower surface average roughness (Ra), lower topographical variations and less scratching. The material removal amount and the Ra were 124 and 7.61 nm with appropriate values of the process parameters of the oxidizer, oxidizer content, abrasive content, slurry flow rate and polishing time which were H2O2, 2 wt.%, 1 wt.%, 10 ml/min, 5 min, respectively.

Originality/value

Based on SEM determinations of the process parameters for the polishing of the surfaces, the CMP mechanism was deduced preliminarily.

Details

Industrial Lubrication and Tribology, vol. 66 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

1 – 10 of 485