Process control for WAAM using computer vision

This study is mainly about the vision system and control algorithm programming for wire arc additive manufacturing (WAAM). Arc additive manufacturing technology is formed by the principle of heat source cladding produced by welders using molten inert gas shielded welding (MIG), tungsten inert gas shielded welding (TIG) and layered plasma welding power supply (PA). It has high deposition efficiency, short manufacturing cycle, low cost, and easy maintenance. Although WAAM has very good uses in various fields, the inability to control the adding process in real time has led to defects in the weld and reduced quality. Therefore, it is necessary to develop the real-time feedback through computer vision and algorithms for WAAM to ensure that the thickness and the width of each layer during the addition process are the same

3D printed dielectric Fresnel lens

© 2016 European Association of Antennas and Propagation.This paper presents the design and fabrication of a zone plate Fresnel lens. 3D Printing is used for rapid prototyping this low-cost and light-weight lens to operate at 10 GHz. This lens is comprised of four different 3D printed dielectric zones to form phase compensation in a Fresnel lens. The dielectric zones are fabricated with different infill percentage to create tailored dielectric constants. The dielectric lens offers 18 dBi directivity at 10 GHz when illuminated by a waveguide source

Design advances of embroidered fabric antennas

Wearable technology has attracted global attention in the last decade and the market is experiencing an unprecedented growth. Wearable devices are designed to be low-profile, light-weight and integrated seamlessly into daily life. Comfort is one of the most important requirements for wearable devices. Fabric based antennas are soft, flexible and can be integrated into clothing. State of the art textile manufacturing techniques such as embroidery, combined with advanced conductive textile materials can be used to fabricate flexible fabric based on-body antennas. In this thesis, the feasibility of using computerised embroidery in the fabrication of wearable, flexible yet functional fabric based antennas have been examined. The fabric based antennas are embroidered using conductive threads. The most suitable materials for fabricating embroidered antennas have been identified. The embroidered fabric based antenna systems including transmission lines and low-profile detachable connectors have been fabricated and their RF performances have been tested. The optimal manufacturing parameters related to embroidery such as stitch direction, spacing and length have been examined. The repeatability of embroidered antennas, cost estimation, and complexity of manufacturing process have been clearly presented. The results can be used to inform and provide guidelines for the development of representative products that can be mass manufactured. A new simulation approach has been introduced to analyse the anisotropic properties of embroidered conductive threads. Simulations and measurements indicate that the performances of embroidered antennas are affected by the anisotropic surface current due to the embroidered stitches. Exploiting the current direction, a novel non-uniform meshed patch antenna has been designed. Representative results show that the non-uniform meshed structure can significantly reduce more than 75% of the usage of conductive materials for the microstrip antennas with negligible effect on the antenna performance

Three-dimensional printed millimetre wave dielectric resonator reflectarray

Reflectarray antennas have attracted extensive attention due to their low loss, high gain, compact volume, and their excellent abilities to control the radiated beam. The use of dielectric resonators as the reflectarray elements minimises the ohmic loss and the coupling between elements. This study uses fused deposition modelling (FDM) three-dimensional (3D) printing rapidly prototyping a low cost and light-weight dielectric resonator reflectarray. The demonstrated reflectarray is composed of 625 3D printed dielectric resonator elements to control the reflected phase over the reflector surface. The total size is 12 × 12 cm2 and the mass is 67 g. Measurements show that this reflectarray provides 28 dBi gain at 30 GHz when offset fed by a Ka-band horn antenna. This work demonstrates the potential of FDM for millimetre wave (mm-wave) applications. The new 3D printing approach can be deployed for high-gain mm-wave antenna fabrication with significantly reduced labour time and material costs

Does Digital Transformation Promote Breakthrough Green Innovation? Empirical Evidence from Listed Chinese Manufacturing Companies

In the current era of digital economy, green innovation has gradually become an important symbol of the green development of enterprises. This paper accelerates the coordinated development of digitalization and “greenization” by using panel data from China’s A-share-listed manufacturing companies from 2007 to 2019 to study the relationship between digital transformation and breakthrough green innovation. The empirical results reveal that the source of the increase in the number of green patents promoted by digital transformation is not the breakthrough innovation reflecting quality and effect, but demonstrates technical similarity. Further analysis demonstrates that enterprises in technology-intensive industries and strong market competition environment will be more inclined toward breakthrough green innovation after a digital transformation. This study empirically supports green transformations of manufacturing enterprises while providing new ideas for cultivating enterprises to choose high-quality green innovation modes