Bend radius

About: Bend radius is a research topic. Over the lifetime, 3303 publications have been published within this topic receiving 35415 citations. The topic is also known as: minimum bend radius.

A digital manufacturing process for three-dimensional electronics

Abstract: Additive manufacturing (AM) offers the ability to produce devices with a degree of three-dimensional complexity and mass customisation previously unachievable with subtractive and formative approaches. These benefits have not transitioned into the production of commercial electronics that still rely on planar, template-driven manufacturing, which prevents them from being tailored to the end user or exploiting conformal circuitry for miniaturisation. Research into the AM fabrication of 3D electronics has been demonstrated; however, because of material restrictions, the durability and electrical conductivity of such devices was often limited. This thesis presents a novel manufacturing approach that hybridises the AM of polyetherimide (PEI) with chemical modification and selective light-based synthesis of silver nanoparticles to produce 3D electronic systems. The resulting nanoparticles act as a seed site for the electroless deposition of copper. The use of high-performance materials for both the conductive and dielectric elements created devices with the performance required for real-world applications. For printing PEI, a low-cost fused filament fabrication (FFF); also known as fused deposition modelling (FDM), printer with a unique inverted design was developed. The orientation of the printer traps hot air within a heated build environment that is open on its underside allowing the print head to deposit the polymer while keeping the sensitive components outside. The maximum achievable temperature was 120 °C and was found to reduce the degree of warping and the ultimate tensile strength of printed parts. The dimensional accuracy was, on average, within 0.05 mm of a benchmark printer and fine control over the layer thickness led to the discovery of flexible substrates that can be directly integrated into rigid parts. Chemical modification of the printed PEI was used to embed ionic silver into the polymer chain, sensitising it to patterning with a 405 nm laser. The rig used for patterning was a re-purposed vat-photopolymerisation printer that uses a galvanometer to guide the beam that is focused to a spot size of 155 µm at the focal plane. The positioning of the laser spot was controlled with an open-sourced version of the printers slicing software. The optimal laser patterning parameters were experimentally validated and a link between area-related energy density and the quality of the copper deposition was found. In tests where samples were exposed to more than 2.55 J/cm^2, degradation of the polymer was experienced which produced blistering and delamination of the copper. Less than 2.34 J/cm^2 also had negative effect and resulted in incomplete coverage of the patterned area. The minimum feature resolution produced by the patterning setup was 301 µm; however, tests with a photomask demonstrated features an order of magnitude smaller. The non-contact approach was also used to produce conformal patterns over sloped and curved surfaces. Characterisation of the copper deposits found an average thickness of 559 nm and a conductivity of 3.81 × 107 S/m. Tape peel and bend fatigue testing showed that the copper was ductile and adhered well to the PEI, with flexible electronic samples demonstrating over 50,000 cycles at a minimum bend radius of 6.59 mm without failure. Additionally, the PEI and copper combination was shown to survive a solder reflow with peak temperatures of 249°C. Using a robotic pick and place system a test board was automatically populated with surface mount components as small as 0201 resistors which were affixed using high-temperature, Type-V Tin-Silver-Copper solder paste. Finally, to prove the process a range of functional demonstrators were built and evaluated. These included a functional timer circuit, inductive wireless power coils compatible with two existing standards, a cylindrical RF antenna capable of operating at several frequencies below 10 GHz, flexible positional sensors, and multi-mode shape memory alloy actuators.

Superconducting magnet based on ReBCo coating superconducting sheet

Abstract: The invention relates to a superconducting magnet based on a ReBCo coating superconducting sheet. Each superconducting sheet and each insulating sheet both adopt a circular ring sheet structure, and the inner diameter and the outer diameter of the superconducting sheet and the insulating sheet are the same; the insulating sheets and the superconducting sheets are arranged alternately to form the superconducting magnet; and flanges are arranged on the upper and lower parts of the superconducting magnet, and the flanges are fixedly connected through an insulating pull rod. By virtue of the superconducting sheets, bending and winding links are omitted, so that the superconducting magnet can be manufactured conveniently; meanwhile, the superconducting magnet is simple in structure and has no limitation on the bending radius; only simple stacking instead of deforming, is required in the forming process of the superconducting magnet, so that influence to the flow capacity of the superconducting material is low; the superconducting magnet, the outer radius of which is slightly smaller than the inner radius, can be combined and nested at occasions where higher magnetic field is required, so as to obtain the required magnetic field; liquid nitrogen is adopted to provide a low-temperature environment; the superconducting magnet is excited by adopting a flux pump technology; and in addition, by combination of the advantages of the high-temperature superconducting ReBCo coating conductor, low-temperature liquid nitrogen cooling, and the flux pump, the superconducting magnet has the advantages of low power consumption, high efficiency, simple structure, and simple and convenient operation.

Experimental Quantification of Local Pressure Loss at a 90° Bend in Low-Pressure Dilute-Phase Pneumatic Conveying of Coarse Particles

Abstract: Focusing on the insufficient estimation of the local pressure loss at a 90° horizontal-vertical bend in low-pressure pneumatic conveying of coarse particles, experiments are conducted in a 80 mm inner diameter test bend by using polyethylene particles having an equivalent spherical diameter of 4.00 mm. The influences of the local pressure loss versus the gas flow Reynolds number, the solid-gas ratio, and the bending radius ratio are investigated. Based on the additional pressure theory of Barth, an empirical formula estimating the local pressure loss is obtained using dimensional and nonlinear regression analysis. Summarizing the experiments and literature, the results expound on the local gas flow pressure loss coefficient decreases with increasing Reynolds number, and first decreases and then increases with increasing bending radius ratios from 0.5 to 7. The additional solid flow pressure loss coefficient decreases with the increasing Reynolds number and bending radius ratio in the dilute phase, and linearly increases with increasing solid-gas ratio. Compared with the estimated values with the experimental values, the calculated standard deviation is below 4.11%, indicating that the empirical formula can be used to predict local pressure loss at the bend in the low-pressure dilute-phase pneumatic conveying.

High performance visible-SWIR flexible photodetector based on large-area InGaAs/InP PIN structure

Abstract: Abstract Mechanically flexible optoelectronic devices and systems can enable a much broader range of applications than what their rigid counterparts can do, especially for novel bio-integrated optoelectronic systems, flexible consumer electronics and wearable sensors. Inorganic semiconductor could be a good candidate for the flexible PD when it can keep its high performance under the bending condition. Here, we demonstrate a III–V material-based flexible photodetector operating wavelength from 640 to 1700 nm with the high detectivity of 5.18 × 10 11 cm‧Hz 1/2 /W and fast response speed @1550 nm by using a simply top-to-down fabrication process. The optoelectrical performances are stable as the PDs are exposed to bending cycles with a radius of 15 mm up to 1000 times. Furthermore, the mechanical failure mode of the PD is also investigated, which suggests that the cracking and delamination failure mode are dominant in bending up and bending down direction, respectively. Such a flexible III–V material-based PD and design with stable and high performance could be a promising strategy for the application of the flexible broad spectrum detection.

Hot bending method for metal tube and device therefor

Abstract: PROBLEM TO BE SOLVED: To provide a hot bending method for a metal tube, which can eliminate conventional constraint regarding a bending radius ratio by preventing stress imbalance accompanying the bending process from leading to irregular deformation, and a device therefor SOLUTION: The front end of a metal tube 1 to be bent is gripped by a front clamping unit 15 of a bending arm 14 which turns with a central axis 12 as the center The rear end of the metal tube 1 is gripped by a rear clamping unit 21 of a propulsion unit 18 placed at the rear of a heating/cooling apparatus 16 In the bending process, the metal tube 1 heated and cooled by the heating/cooling apparatus 16 is advanced by the propulsion unit 18 and is bent by the turn of the bending arm 14, with the metal tube 1 being clamped by the clamping units 15 and 21 with a clamping margin which produces elastic diameter shrinkage, whereby the metal tube 1 is bent in a state of lessening flattening stress generated in a plane intersecting with the locus of the center of the metal tube 1 at right angles, with the application of bending moment COPYRIGHT: (C)2007,JPO&INPIT