GKN

About: GKN is a company organization based out in Newton, North Carolina, United States. It is known for research contribution in the topics: Machining & Gas compressor. The organization has 271 authors who have published 430 publications receiving 6874 citations. The organization is also known as: GKN plc & Guest, Keen and Nettlefolds.

A Simple, Low-Cost Conductive Composite Material for 3D Printing of Electronic Sensors

Abstract: 3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes (‘rapid prototyping’) before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term ‘carbomorph’ and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes.

Microstructure and Mechanical Properties of Wire and Arc Additive Manufactured Ti-6Al-4V

Abstract: Wire and arc additive manufacturing (WAAM) is a novel manufacturing technique in which large metal components can be fabricated layer by layer. In this study, the macrostructure, microstructure, and mechanical properties of a Ti-6Al-4V alloy after WAAM deposition have been investigated. The macrostructure of the arc-deposited Ti-6Al-4V was characterized by epitaxial growth of large columnar prior-β grains up through the deposited layers, while the microstructure consisted of fine Widmanstatten α in the upper deposited layers and a banded coarsened Widmanstatten lamella α in the lower layers. This structure developed due to the repeated rapid heating and cooling thermal cycling that occurs during the WAAM process. The average yield and ultimate tensile strengths of the as-deposited material were found to be slightly lower than those for a forged Ti-6Al-4V bar (MIL-T 9047); however, the ductility was similar and, importantly, the mean fatigue life was significantly higher. A small number of WAAM specimens exhibited early fatigue failure, which can be attributed to the rare occurrence of gas pores formed during deposition.

High performance cutting of advanced aerospace alloys and composite materials

Abstract: This paper presents an overview of the recent advances in high performance cutting of aerospace alloys and composite currently used in aeroengine and aerostructure applications. Progress in cutting tool development and its effect on tool wear and surface integrity characteristics of difficult to machine materials such as nickel based alloys, titanium and composites is presented. Further, advances in cutting technologies are discussed, focusing on the role of hybrid machining processes and cooling strategies (MQL, high pressure coolant, cryogenic) on machining performance. Finally, industrial perspectives are provided in the context of machining specific components where future challenges are discussed.

Drill geometry and operating effects when cutting small diameter holes in CFRP

Abstract: The paper details experimental results when drilling small holes (1.5 mm diameter cemented carbide drills with varying end point and helix geometry) in thin quasi-isotropic, unbacked carbon fibre reinforced plastic (CFRP) laminate (typical cutting time ∼0.4 s/hole). The study utilised an L12 Taguchi fractional factorial orthogonal array with analysis of variance (ANOVA) employed to evaluate the effect of drill geometry and drilling conditions on tool life and hole quality. Main effects plots and percentage contribution ratios (PCR) are detailed in respect of response variables and process control factors. More conventionally, tool wear and cutting force data are plotted/tabulated, together with micrographs of hole entry/exit condition and internal hole damage. Drill geometry and feed rate in general had the most effect on measured outputs. Thrust force was typically below 100 N at test cessation; however, drill wear progression effectively doubled the magnitude of force from test outset. Entry and exit delamination factors ( F d ) of ∼1.3 were achieved while the maximum number of drilled holes for a tool life criterion VB B max of ≤100 μm was 2900 holes using a stepped, uncoated drill with a feed rate of 0.2 mm/rev.