Assembly Concept Research Articles

Increasing the Automation Degree in Wiring Harness Assembly by Extending the Standard Crimping Machines by Developed Assembly Concept

In the automotive industry, the assembly of wiring harnesses is done mostly manually. This leads to high labour costs as well as a high number of defects. In order to minimize these disadvantages, both industry and research made huge efforts in recent decades to increase the level of automation in the assembly of wiring harness modules. The fully automated crimping and blockloading machine e.g. Komax Zeta 656, is already successfully used in the industry as a machine for the automated assembly of small wiring harnesses. But still, there is a great potential to increase efficiency and quality in the assembly of wiring harnesses. This paper presents a newly developed machine concept for the fully automated assembly of wiring harnesses. It is shown that the new system can provide higher production efficiency compared to both the competitive systems and manual assembly. The presented concept also helps saving resources as it uses the standard crimping machine as e.g. Komax Alpha 355 as a basis which is already present in many wiring harness factories. To set up the presented mounting machine the Komax Alpha has not to be fully replaced, but only to be extended by a few components.

Synthetic biology engineering of biofilms as nanomaterials factories.

Bottom-up fabrication of nanoscale materials has been a significant focus in materials science for expanding our technological frontiers. This assembly concept, however, is old news to biology - all living organisms fabricate themselves using bottom-up principles through a vast self-organizing system of incredibly complex biomolecules, a marvelous dynamic that we are still attempting to unravel. Can we use what we have gleaned from biology thus far to illuminate alternative strategies for designer nanomaterial manufacturing? In the present review article, new synthetic biology efforts toward using bacterial biofilms as platforms for the synthesis and secretion of programmable nanomaterials are described. Particular focus is given to self-assembling functional amyloids found in bacterial biofilms as re-engineerable modular nanomolecular components. Potential applications and existing challenges for this technology are also explored. This novel approach for repurposing biofilm systems will enable future technologies for using engineered living systems to grow artificial nanomaterials.

One-Step Assembly of Molecular Separation Membranes by Direct Atomizing Oligomers.

Polymeric membranes are important materials for efficient sieving of targeted components at the molecular level and have made significant advancement in many industrial applications such as biofuel production, water purification, fuel combustion, and carbon dioxide capture. Although their separation efficiencies have been widely investigated, lack of more efficient, greener, and lower-cost membrane fabrication mechanisms is still a major hurdle for mass production, because the conventional membrane-making process is always time-consuming, highly inefficient, and consumes a large amount of organic solvents. Herein we report a one-step assembly concept capable of directly processing low-viscosity oligomers into polymer-based molecular separation membranes in an ultrafast and green manner. This process was implemented by alternate atomizing-depositing of low-viscosity oligomers and reaction auxiliary agents onto a rotating support and followed by an ultrafast interfacial reaction under solvent-free conditions. Without the need for dissolution processing of polymer, solvent evaporation, and any post-treatments, the whole technological process could be accomplished within a few seconds/minutes, which is 2-3 orders of magnitude faster than conventional solution-coating technologies. The universality of this facile approach has also been demonstrated by successfully producing various defect-free polymeric membranes and homodispersed nanohybrid membranes with excellent and stable performance for bioalcohol production and recovery of different trace organics from dilute solutions.

Architecture for in-space robotic assembly of a modular space telescope

An architecture and conceptual design for a robotically assembled, modular space telescope (RAMST) that enables extremely large space telescopes to be conceived is presented. The distinguishing features of the RAMST architecture compared with prior concepts include the use of a modular deployable structure, a general-purpose robot, and advanced metrology, with the option of formation flying. To demonstrate the feasibility of the robotic assembly concept, we present a reference design using the RAMST architecture for a formation flying 100-m telescope that is assembled in Earth orbit and operated at the Sun–Earth Lagrange Point 2.

Assessment of subchannel code ASSERT-PV for supercritical applications

The Canadian subchannel code ASSERT-PV has been modified and used in the development of a fuel assembly concept for the Canadian Supercritical Water-cooled Reactor (SCWR). This paper describes the modification to ASSERT-PV for the SCWR applications, and presents an assessment of the code against available experimental data. Full-bundle tests for the SCWR fuel assembly are not yet available; therefore, partial-bundle tests with a reduced number of rods and a shortened channel length were considered in the assessment. Three heat transfer experiments at supercritical pressures were selected for the assessment: (i) a Japanese 7-rod bundle water experiment; (ii) a Chinese 2×2 rod bare-bundle water experiment; and (iii) a Russian 7-rod bare-bundle Freon experiment. The rod surface temperature was taken as the key parameter in the assessment since the maximum fuel cladding temperature is a key criterion used in developing the SCWR fuel assembly concept. The ASSERT-PV predictions of rod surface temperature were compared against experimental data of measured wall temperatures. Six widely-known heat transfer correlations were assessed for their suitability in predicting the wall temperatures in rod bundles under conditions relevant to the Canadian SCWR. Overall, the Jackson correlation was found to be the most suitable for predicting the wall temperatures in the range of conditions covered by the selected experiments.

In Vitro Assembly Kinetics of Cytoplasmic Intermediate Filaments: A Correlative Monte Carlo Simulation Study.

Intermediate filament (IF) elongation proceeds via full-width “mini-filaments”, referred to as “unit-length” filaments (ULFs), which instantaneously form by lateral association of extended coiled-coil complexes after assembly is initiated. In a comparatively much slower process, ULFs longitudinally interact end-to-end with other ULFs to form short filaments, which further anneal with ULFs and with each other to increasingly longer filaments. This assembly concept was derived from time-lapse electron and atomic force microscopy data. We previously have quantitatively verified this concept through the generation of time-dependent filament length-profiles and an analytical model that describes assembly kinetics well for about the first ten minutes. In this time frame, filaments are shorter than one persistence length, i.e. ~1 μm, and thus filaments were treated as stiff rods associating via their ends. However, when filaments grow several μm in length over hours, their flexibility becomes a significant factor for the kinetics of the longitudinal annealing process. Incorporating now additional filament length distributions that we have recorded after extended assembly times by total internal reflection fluorescence microscopy (TIRFM), we developed a Monte Carlo simulation procedure that accurately describes the underlying assembly kinetics for large time scales.

Self-organized architectures from assorted DNA-framed nanoparticles.

The science of self-assembly has undergone a radical shift from asking questions about why individual components self-organize into ordered structures, to manipulating the resultant order. However, the quest for far-reaching nanomanufacturing requires addressing an even more challenging question: how to form nanoparticle (NP) structures with designed architectures without explicitly prescribing particle positions. Here we report an assembly concept in which building instructions are embedded into NPs via DNA frames. The integration of NPs and DNA origami frames enables the fabrication of NPs with designed anisotropic and selective interactions. Using a pre-defined set of different DNA-framed NPs, we show it is possible to design diverse planar architectures, which include periodic structures and shaped meso-objects that spontaneously emerge on mixing of the different topological types of NP. Even objects of non-trivial shapes, such as a nanoscale model of Leonardo da Vinci's Vitruvian Man, can be self-assembled successfully.

Interlocking assembled 3D auxetic cellular structures

As promising metamaterials, 3D periodic auxetic cellular structures (PACSs) have attracted great interest. However, they usually consist of intricate geometries which make their fabrication a significant challenge. The present paper is focused on introducing the interlocking assembly concept into the fabrication of 3D PACSs. There are distinct advantages of the interlocking assembly method compared with the additive manufacturing methods mainly used before. Based on the interlocking assembly method, the dependences of mechanical properties mainly including the Poisson's ratio and the Young's modulus of the structure on the re-entrant angle were investigated through a combination of uniaxial compression experiments and numerical simulations, excellent qualitative and quantitative agreement was found. Using the experimentally verified numerical model, the effects of the strut thickness and the ratio of the vertical strut length to oblique strut length on the mechanical properties of the structure were investigated. Results show that the compression modulus of the structure will increase with the structure becomes more re-entrant, but there exists an extreme value for Poisson's ratio with the re-entrant angle around 45° which differs from former studies. With the thickening of the struts the compression modulus of the structure monotonously increases and the Poisson's ratio of the structure will gradually changes from negative to positive then gradually approaches to the Poisson's ratio of the parent material. The vertical strut length to oblique strut length ratio plays fewer roles on the mechanical properties compared with the re-entrant angle and the strut thickness.

Concept for Magnet Intra Logistics and Assembly Supporting the Improvement of Running Characteristics of Permanent Magnet Synchronous Motors

Current scientific studies prove the dependency of the running characteristics of permanent magnet synchronous motors on variations of the physical properties of permanent magnets and manufacturing errors. Currently, this fact is not considered in most process chains for magnet and rotor assembly. Thus, insufficient rotor quality can only be detected during the end-of-line test, causing rejects of whole motors. As a solution for these drawbacks, a computerized magnet intra-logistics storage and assembly concept is presented, using sophisticated magnet measurement technologies. This concept allows for the traceability of single magnets and enables to compensate variations of the magnetic properties by selective magnet assembly.

Drivers of Complexity in a Flexible Assembly System- A Case Study

Various ever-changing market demands have propelled manufacturing companies to offer product variety in an efficient and timely manner. Assembly as a key stage of manufacturing operations is used to realise product variety through establishing mixed-product assembly lines. Although establishing a flexible mixed-product assembly system which both offers product variety and absorbs market demands fluctuation is pivotal for maintaining competitive edge in certain industries such as vehicle manufacturing, it is also considered an elaborate task which calls for further investigation. In this paper, complexity in a flexible mixed-product assembly system is investigated and the key drivers of complexity are identified. To fulfil the research objective, a case study during the pilot implementation of a flexible mixed-product assembly concept in a heavy vehicle manufacturing company has been conducted. The results indicate the key factors concerning assembly operation, product design, and information and communication technology (ICT) which contribute to complexity in the flexible assembly system. The paper concludes with an outlook for possible future research.

Characterization Studies of a New MEA Structure for Polymer Electrolyte Fuel Cells

A new membrane electrode assembly (MEA) concept is recently introduced, where the carbon paper substrate is eliminated and the entire gas diffusion layer (GDL) consists of only the micro-porous layer (MPL). The MPL is directly deposited onto both sides of the catalyst coated membrane (CCM), which simplifies the fabrication and assembly, and provides an improvement in the interfacial contact between the MPL and the catalyst layer. This method also allows a functional gradation of the MPL for improved mechanical strength as well as optimized gas transport and water removal. A spray deposition method is used for depositing this MPL onto a commercial CCM. The sprayed MPL on the CCM produces a robust MPL/CL interface. The results show that this new method of MEA fabrication can provide high power density operation, and that mass transport can be improved.

Welding technology on sector assembly of the JT-60SA vacuum vessel

Manufacturing of JT-60SA Vacuum Vessel (VV) is under the onsite sector assembly, where ten VV sectors are to be welded together into a torus. The vessel is 6.6m height and 5m major radius and a double wall structure with the thickness of 18mm and locally 30mm, and total dimensional tolerance is designed to avoid any interference due to operational displacements. In this paper, two issues are focused: the onsite sector assembly concept and sector welding technology. The assembly concept is a contrivance to fulfil high precision as a large torus VV and efficient procedure, and obtained with combination of the direct butt joint and splice plate joint. The welding technology is a method to realize the VV, and investigated on acceptable error sizes with the test pieces for the onsite manipulator welding. Correction method of sector edge is also confirmed by the mock-up. Moreover, application to the onsite sector assembly is discussed. The onsite assembly has been started by this concept with its welding technology.

3-D Mechanical Analysis of the ECR Source Magnet for FRIB

The ECR source magnet of the FRIB facility has been designed by the Superconducting Magnet Program at the Lawrence Berkeley National Laboratory (LBNL). The magnetic parameters are close to the VENUS magnet (sextupole-in-solenoids) operated at LBNL. The mechanical assembly concept, however, is different and uses a shell-based support structure. The main advantage of this structure is the ability to finely tune the sextupole prestress both azimuthally (by way of bladder and key technology, and axially by means of end plates. This method of structural pre-loading applies the desired compression on the sextupole coils while maintaining acceptable peak stresses. Also, bladder and key technology is a reversible assembly process allowing fast and easy coil replacement, when necessary. This paper also describes the mechanical analysis required to estimate the sextupole and solenoids preloads. The stress distribution in the windings and structural components are presented during assembly, cool-down, and magnet excitation.

Strain Management in HTS High Current Cables

The best performing HTS conductors are available in the form of thin tapes with operating current in the range of 200 A at the operating conditions. To realize conductors with high current carrying capability, in the range of several tens of kA, a large number of tapes must be assembled in a cable. The conventional stranding methods for round conductors are not applicable to thin tapes. CRPP has developed an assembly concept based on twisted stacks of tapes soldered into a copper profile. The ability to withstand bending and torsion strain is the main issue for the design of a high current flat cable based on twisted stacks of HTS tapes. An analytical mechanical model was developed and validated with the results of measurements. Parametric analyses are used to select the optimum layout for the first full size prototype of the coming HTS conductor for fusion. Various configurations of the cable are presented and compared, paying attention in particular to the strain acting in the tape. The chosen set of cable parameters satisfies electromechanical limitations and provides feasibility of strand winding.

Swelling and mechanical properties of hydrogels composed of binary blends of inter-linked pH-responsive microgel particles.

We show that a new type of hydrogel can be prepared by covalently inter-linking binary blends of microgel (MG) particles and that the swelling ratio and modulus of the gels can be predicted from their composition. In previous work we established that physical gels of glycidyl methacrylate (GMA) functionalised poly(methyl methacrylate-co-methacrylic acid-co-ethyleneglycol dimethacrylate) microgel particles (GMA-MG) could be covalently inter-linked to give hydrogels, termed doubly crosslinked microgels, DX MGs. We build on this concept here by investigating the properties of DX MGs containing binary blends of GMA-MG particles and glycidyl oligo(ether ester) acrylate-functionalised microgel particles (GOE-MG). These new hydrogels were assembled by inter-linking nanoscale MG building blocks in the absence of small molecule monomers or crosslinkers. The volume fraction of GMA-MG particles used to prepare the GOE-GMA DX MGs was systematically varied. Rheology data showed that inclusion of GMA-MG and GOE-MG within the GOE-GMA DX MGs increased the modulus and yield strain, respectively, compared to the values measured for the respective physical gels. The data for the covalent GOE-GMA DX MG gels showed that the ductility increased with increasing GOE-MG content. GOE provided covalent inter-linking of the MG particles and also acted as a lubricant between particles due to its low Tg. By demonstrating compositionally determined swelling and mechanical properties for DX MG gels prepared using binary blends of MG particles, this study introduces a new, widely applicable, hydrogel construction assembly concept that is not available for conventional hydrogels.

Modular assembly concept for 3D neural probe prototypes offering high freedom of design and alignment precision.

The new assembly technology developed in this research provides a means to extend planar intracortical neural probes with one-dimensional (1D) and two-dimensional (2D) electrode arrangements into complex three-dimensional (3D) neural probes. The approach is based on novel silicon stacking modules realized using microsystems technologies. With these microcomponents, 3D probes can be assembled flexibly and tailored to the demands of neuroscientific experiments. The manufacturing process of the stacking modules provides the possibility to adjust the electrode spacing in the stacking direction with micrometer precision. The assembly method is demonstrated with 32-channel systems comprising 7-mm-long and 50-μm-thin neural probes. The angular alignment between the neural probes and their stacking modules after assembly as well as the vertical electrode pitch were determined to be about 1° and 353±15 μm, respectively.

Ultimate Trough® – A Significant Step towards Cost-competitive CSP

Parabolic trough collectors are so far the most successful and mature concentrating solar power technology on the market. Recent development towards higher performance and significant cost reductions leads to further improvements in competitiveness. FLABEG GmbH started its development of the ULTIMATE TROUGH® (UT) collector in 2010, jointly with sbp sonne gmbh, and with scientific support from the German Aerospace Center (DLR) and Fraunhofer Institute for Material Flow and Logistics (FhG-IML). With the successful installation of an indoor prototype in 2011, the assembly concept and optical performance was validated. In the second half of 2012, a demonstration loop consisting of two collectors with 3,400 m2 total aperture area, has been assembled and integrated into a commercial plant in the US. The loop is in operation since January 2013.The present paper presents the first experiences and especially the very promising performance results of the demonstration loop. Cost savings and related reduction of levelized costs of electricity (LCOE) are illustrated.

Simulation of RF MEMS based matching networks and a single pole double throw switch for Multiband T/R Modules

Abstract. This work presents concepts and designs for two essential components of a frequency agile transmit and receive module based on Radio Frequency Micro Electro Mechanical System (RF MEMS) switches for the frequency range from 3.5 GHz up to 8.5 GHz. The advantages of a variable power amplifier (PA) matching compared to a fixed broadband solution are examined and discussed in context with the designed components. To demonstrate the principle functionality, an assembly concept is presented, which allows for the integration of a frequency agile 6 W power amplifier with surrounding components like phase shifters, switches and antennas. An RF MEMS switching element is introduced as a high isolation polarization switch, featuring low insertion loss as well as almost no DC power consumption.

Accurate integration of segmented x-ray optics using interfacing ribs

Future lightweight and long-focal-length x-ray telescopes must guarantee a good angular resolution (e.g., 5 arc sec HEW) and reach an unprecedented large effective area. This goal can be reached with the slumping of borosilicate glass sheets that allow the fabrication of lightweight and low-cost x-ray optical units (XOU). These XOUs, based on mirror segments, have to be assembled together to form complete multishell Wolter-I optics. The technology for the fabrication and the integration of these XOUs is under development in Europe, funded by European Space Agency, and led by the Brera Observatory (INAF-OAB). While the achievement of the required surface accuracy on the glass segments by means of a hot slumping technique is a challenging aspect, adequate attention must be given to the correct integration and coalignment of the mirror segments into the XOUs. To this aim, an innovative assembly concept has been investigated, based on glass reinforcing ribs. The ribs connect pairs of consecutive foils, stacked into a XOU, with both structural and functional roles, providing robust monolithic stacks of mirror plates. Moreover, this integration concept allows the correction of residual low-frequency errors still present on the mirror foil profile after slumping. We present the integration concept, the related error budget, and the results achieved so far with a semi-robotic integration machine especially designed and realized to assemble slumped glass foils into XOUs.

High-performance mesoporous LiFePO4 from Baker's yeast

Based on the biomineralization assembly concept, a simple and inexpensive biomimetic sol–gel method is found to synthesize high-performance mesoporous LiFePO4 (HPM-LFP). The key step of this approach is to apply Baker's yeast cells as both a structural template and a biocarbon source. The formation mechanism of ordered hierarchical mesoporous network structure is revealed by characterizing its morphology and microstructure. The HPM-LFP exhibits outstanding electrochemical performances. The HPM-LFP has a high discharge capacity (about 153mAhg−1 at a 0.1 C rate), only 2% capacity loss from the initial value after 100 cycles at a current density of 0.1 C. This simple and potentially universal design strategy is currently being pursued in the synthesis of an ideal cathode-active material for high power applications.