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This paper aims to investigate the effect of post-processing techniques on dimensional accuracy of laser sintering (LS) of Nylon and Alumide^® and fused deposition modelling (FDM) of acrylonitrile butadiene styrene (ABS) materials.

Additive manufacturing (AM) of test pieces using LS of Nylon and Alumide^® powders, as well as the FDM of ABS materials, were first conducted. Next, post-processing of the test pieces involved tumbling, shot peening, hand finishing, spray painting, CNC machining and chemical treatment. Touch probe scanning of the test pieces was undertaken to assess the dimensional deviation, followed by statistical analysis using Chi-square and Z-tests.

The deviation ranges of the original built parts with those being subjected to tumbling, shot peening, hand finishing, spray painting, CNC machining or chemical treatment were found to be different. Despite the rounding of sharp corners and the removal of small protrusions, the dimensional accuracy of relatively wide surfaces of Nylon or Alumide^® test pieces were not significantly affected by the tumbling or shot peening processes. The immersion of ABS test pieces into an acetone bath produced excellent dimensional accuracy.

Only Nylon PA2200 and Alumide^® processed through LS and ABS P400 processed through FDM were investigated. Future work could also examine other materials and using parts produced with other AM processes.

The service bureaus that produce prototypes and end-use functional parts through AM will be able to apply the findings of this investigation.

This research has outlined the differences of post-processing techniques such as tumbling, shot peening, hand finishing, spray painting, CNC machining and chemical treatment. The paper discusses the advantages and disadvantages of each of those methods and suggests that the immersion of ABS test pieces into an acetone bath produced excellent dimensional accuracy.

The purpose of this paper is to extend existing knowledge of 4D printing, in line with Khoo et al. (2015) who defined the production of 4D printing using a single material, and 4D printing of multiple materials. It is proposed that 4D printing can be achieved through the use of functionally graded materials (FGMs) that involve gradational mixing of materials and are produced using an additive manufacturing (AM) technique to achieve a single component.

The latest state-of-the-art literature was extensively reviewed, covering aspects of materials, processes, computer-aided design (CAD), applications and made recommendations for future work.

This paper clarifies that functionally graded additive manufacturing (FGAM) is defined as a single AM process that includes the gradational mixing of materials to fabricate freeform geometries with variable properties within one component. The paper also covers aspects of materials, processes, CAD, applications and makes recommendations for future work.

This paper examines the relationship between FGAM and 4D printing and defines FGAM as a single AM process involving gradational mixing of materials to fabricate freeform geometries with variable properties within one component. FGAM requires better computational tools for modelling, simulation and fabrication because current CAD systems are incapable of supporting the FGAM workflow.

It is also identified that other factors, such as strength, type of materials, etc., must be taken into account when selecting an appropriate process for FGAM. More research needs to be conducted on improving the performance of FGAM processes through extensive characterisation of FGMs to generate a comprehensive database and to develop a predictive model for proper process control. It is expected that future work will focus on both material characterisation as well as seamless FGAM control processes.

This paper examines the relationship between FGAM and 4D printing and defines FGAM as a single AM process that includes gradational mixing of materials to fabricate freeform geometries with variable properties within one component.

The purpose of this paper is to investigate the technology, business and intellectual property issues surrounding the production of spare parts through additive manufacturing (AM) from a digital source. It aims to identify challenges to the growth of the AM spares market and propose suitable solutions.

The paper begins with a systematic literature review and theoretical analysis. This is followed by case study research through semi-structured interviews, forming the basis of a triangulated, cross-case analysis of empirical data.

The paper identifies several obstacles to the development of the AM-produced digital spares market. The manufacturing industry will soon be forced to re-think AM as a real manufacturing alternative. Short-term, AM technology has implications for the production of components for legacy systems for which tooling facilities no longer exist. Long-term, AM will be used to produce a wide range of components especially when product and/or service functionality can be increased. To enable companies to navigate current uncertainties in the patent framework (especially the “repair vs make” doctrine), new intellectual property rights strategies could be developed around patenting both complex devices and their individual components, and seeking patent protection for CAD files. Further harmonization of the EU legal framework, the interpretation of claims and the scope of protection offered in the context of spare parts, will also be important.

This study pinpoints key issues that need to be addressed within the European AM business environment and the patent system and proposes recommendations for business and legal frameworks to promote the growth of a stable European digital spare parts market.

The purpose of this paper is to investigate the adhesion of polymer materials printed directly onto fabrics using entry-level fused deposition modelling (FDM) machines. A series of functional and decorative parts were designed to explore the limitations and to identify potential applications.

A series of shapes and structures were designed as 3D computer-aided design (CAD) solids to determine whether complex parts could be printed directly onto the surface of fabrics. The structures were fabricated using an entry-level FDM printer with acrylonitrile butadiene styrene, polylactic acid (PLA) and nylon on eight different types of synthetic and man-made woven and knit fabrics. The results were recorded according to four parameters – the warp, bond, print quality and flex – before comparing the data sets.

Among the three polymers, PLA showed the best results when printed on the eight different types of fabrics, having extremely good adhesion with little warp, yet displaying a high quality of print with good flexural strength. For the fabrics, woven cotton, woven polywool and knit soy had excellent adhesion when the three polymers were deposited.

Future work should cover a wider range of polymers and textiles and incorporate more functional features for testing. Other aspects include modifying the fibre surface through mechanical or chemical means to achieve a more efficient adhesion with the fibre and examining the deposition process in terms of temperature, pressure and build density. Future work should also investigate the feasibility for large-scale production.

This paper supports work on wearable electronics by integrating comfortable textiles with hard wearing parts without compromising on quality and fit and combining additive manufacturing processes with textiles to maintain the drape characteristics of the fabric. Polymer–textile deposition will contribute to new applications and functional products such as orthopaedic braces for medical use or for decorative features such as buttons and trimmings for garments.

This paper has contributed to new knowledge by providing a better understanding of polymer materials being printed directly onto fabrics using entry-level FDM machines.

The purpose of this paper is to identify the strengths and weaknesses associated with physical and virtual prototyping and propose an approach that utilises a real‐time integration of both methods through an automated process.

Following a literature review, the paper presents the results of a survey investigating the current use of prototyping. It then discusses a series of trials that were developed for the proposed tool.

Physical and virtual prototypes are not competitive but rather complementary. An integrated real‐time system would reduce cost and shorten the product design process.

This paper provides recommendations on how real‐time integration of both physical and virtual prototypes could potentially streamline the new product development process.

The purpose of this article is to reviews state-of-the-art developments in four-dimensional (4D) printing, discuss what it is, investigate new applications that have been discovered and suggest its future impact.

The article clarifies the definition of 4D printing and describes notable examples covering material science, equipment and applications.

This article highlights an emerging technology cycle where 4D printing research has gained traction within additive manufacturing. The use of stimuli-responsive materials can be programmed and printed to enable pre-determined reactions when subject to external stimuli.

This article reviews state-of-the-art developments in 4D printing, discusses what it is, investigates new applications that have been discovered and suggests its future impact.

This paper aims to discuss the use of polyvinyl alcohol (PVA) as a water-soluble support material in desktop three-dimensional (3D) printing. Using a water-soluble material as one of the printing filaments in a dual-extrusion 3D printer provides the flexibility of printing support structures and rafts in complex components and prototypes. This paper focuses on the challenges of acrylonitrile butadiene styrene (ABS)–PVA dual-extrusion printing, and optimal settings and techniques for such hybrid printing.

Several hybrid ABS–PVA parts were printed using a commercial desktop 3D printer. An experimental study was designed to examine the solubility of the PVA support in water by varying four different parameters: length of time in water, water temperature, stirring rate and PVA surface area. The rate of PVA solubility in water was then used to examine its relationship with each parameter.

Numerous problems were encountered while printing ABS–PVA printing parts, including storing the spool of PVA in a dry environment, determining optimal extrusion and build plate temperatures and ABS–PVA adherence during dual extrusion printing. There is no strong literature to address these challenges. Hence, optimal settings and techniques for effective hybrid ABS–PVA were determined. Print yields were also recorded to examine the reliability of ABS–PVA printing.

The tendency of PVA to absorb moisture resulted in a number of build fails and prevented build times longer than 40 minutes. Future work can explore how to print PVA directly from a dry environment.

The optimal settings and techniques for dual-extrusion ABS–PVA printing that are presented in this paper can effectively be used to explore prototyping of geometrically complex parts with PVA as support material.

In addition to the practical implications, the results from this work are a valuable addition to the literature related to printing using water-soluble polymers such as PVA. The experimental methods and techniques of this paper can be used to assess the reliability of similar 3D printing technologies.