Uncertainty Analysis of an Optoelectronic Strain Measurement System for Flywheel Rotors

The strain in a fast spinning carbon fiber flywheel rotor is of great interest for condition monitoring, as well as for studying long-term aging effects in the carbon fiber matrix. Optoelectronic strain measurement is a contactless measurement principle where a special reflective pattern is applied to the rotor which is scanned by a stationary optical setup. It does not require any active electronic components on the rotor and is suited for operation in a vacuum. In this paper, the influences of the key parts comprising the optoelectronic strain measurement are analyzed. The influence of each part on the measurement result including the uncertainty is modeled. The total uncertainty, as well as each part’s contribution is calculated. This provides a valuable assessment of requirements for component selection, as well as tolerances of mechanical parts and processes to reach a final target measurement uncertainty or to estimate the uncertainty of a given setup. We have shown that the edge quality of the special reflective pattern has the strongest influence, and how to improve it. Considering all influences, it is possible to measure strain with an uncertainty of less than 1% at a rotation speed of 500Hz.

Operational Behavior of Graded Diamond Grinding Wheels For End Mill Cutter Machining

The varying related material removal rate during deep grinding of cemented carbide end mill cutters results in an unevenly wear of the grinding wheel. This causes a reduced geometrical precision of the manufactured tools. Consequently, the intervals between dressing steps are reduced and the dressing infeed increases. The aim of this research project is therefore to design a tailored grinding tool with uniform wear behavior. To address this situation, the grinding tool load is determined simulatively along the width of the grinding wheel. From this an equation is derived to adapt the bonding layer properties to the local load differences. First investigations show that two different concentrations zones in the abrasive layer of the grinding wheel improves the wear behavior already. This indicates that a further reduction of the wear difference is possible by a more uniform gradient. A simulation is performed to define a knowledge based gradient with more than two concetration zones. This allows a more precise load optimized adaptation of the grinding layer properties to the geometry to be ground in terms of wear behavior. Grinding tools manufactured on this basis are used for flute grinding of end mill cutters. A reduction of the wear difference over the grindig wheel width of 52% and an improved cutting edge quality of these are demonstrated.

Investigation of the gap bridgeability at high-power laser hybrid welding of plasma-cut thick mild steels with AC magnetic support

One of the challenges of the high-power hybrid laser welding of thick steels is the sensitivity of the process of the process to manufacturing tolerances. This usually leads to a time-consuming preparation of the welding edges, such as milling. The study deals with the influence of the edge quality of milled and plasma-cut steel made of S355J2 with a wall thickness of 20 mm on the laser hybrid welded seam quality. Furthermore, the gap bridgeability and the tolerances towards edge misalignment was investigated. An AC magnet was used as backing support to prevent sagging and positioned under the workpiece, to generate an upwards directed electromagnetic pressure. The profiles of the edges and the gap on the top and root side were measured using a digital camera. Single-pass laser hybrid welds of plasma-cut edges could be welded using a laser beam power of just 13.7 kW. A gap bridgeability up to 2 mm and misalignment of edges up to 2 mm could be achieved successful. Additionally, the independence of the cutting side and the welding side was shown, so that samples were welded to the opposite side to their cutting. For evaluation of internal defects or irregularities, X-ray images were carried out. Charpy impact strength tests were performed to determine the toughness of the welds.

The use of subsurface constructed wetland for the treatment of tofu industrial wastewater in Semanan, Jakarta Barat

The tofu preparing industry, typically done by the little businesses, can be found in almost every city in Indonesia and is dominated by industrial house stairways. The largest industry does not have a unit of processing wastewater. The wastewater focus is as yet over the edge quality norm, which messed contamination up. Constructed wetlands are affordable and reliable green technologies to diminish water contamination by utilizing plants. This study aims to know the quality of tofu industrial wastewater in Semanan, Jakarta Barat and analyze the removal of pollutants. The performance of the horizontal flow type Sub-Surface Flow constructed wetland with Typha latifolia plant. The media used were soil, sand, and gravel with a Typha latifolia plant. Testing the quality of tofu wastewater in Constructed wetland every 7 days at inlet and outlet, the sample was taken for TSS, BOD, and COD concentration. This research showed that the reactor could decrease TSS by 91.17% on day 36, a decrease of BOD 89.30% on day 15, and COD 87.86% on day 36. Those plants can produce growth fertile. These results fulfil the requirement of the quality standards of the Decree of the Minister of Environment No. 05 of 2014.

Study On The Edge Defects of High Volume Fraction 70% SiCp/Al Composites In Ultrasonic-Assisted Milling

Directing at the hard machinability of high volume fraction 70% SiCp/Al composites，a longitudinal and torsional ultrasonic-assisted milling method is proposed to improve the edge quality and machining efficiency. By observing the metallographic structure of the material, the three-dimensional finite element model of SiC particles with spherical, ellipsoidal and random polyhedra is established and analyzed by ABAQUS simulation software. The formation mechanism of edge defects, stress distribution, defect characteristics and the effect of machining parameters on milling force are investigated during ultrasonic-assisted milling. The results show that the edge defects appear at the inlet, outlet and middle edge position, especiallyis more serious at the outlet position. The SiC particles failure modes mainly include particle pullout, particle shearing, crushing, and the edge defects mainly include matrix tearing, edge breakage, burrs, bulgesandpits. In a certain range of ultrasonic amplitude, ultrasonic-assisted milling can effectively reduce the surface fragmentation rate and milling force, slow down the expansion of cracks, increase the plastic flow of material, and obtain better edge quality compared with traditional machining method. By comparing the results of finite element simulation and experimental tests, it shows that the simulation results are in good agreement with the experimental tests.

High-quality percussion drilling with ultrashort laser pulses

The influence of the laser fluence on the quality of percussion-drilled holes was investigated both experimentally and by an analytical model. The study reveals that the edge quality of the drilled microholes depends on the laser fluence reaching the rear exit of the hole and changes with the number of pulses applied after breakthrough. The minimum fluence that must reach the hole’s exit in order to obtain high-quality microholes in stainless steel was experimentally found to be 2.8 times the ablation threshold.

Towards improving edge quality using combinatorial optimization and a novel skeletonize algorithm

Background Object detection and image segmentation of regions of interest provide the foundation for numerous pipelines across disciplines. Robust and accurate computer vision methods are needed to properly solve image-based tasks. Multiple algorithms have been developed to solely detect edges in images. Constrained to the problem of creating a thin, one-pixel wide, edge from a predicted object boundary, we require an algorithm that removes pixels while preserving the topology. Thanks to skeletonize algorithms, an object boundary is transformed into an edge; contrasting uncertainty with exact positions. Methods To extract edges from boundaries generated from different algorithms, we present a computational pipeline that relies on: a novel skeletonize algorithm, a non-exhaustive discrete parameter search to find the optimal parameter combination of a specific post-processing pipeline, and an extensive evaluation using three data sets from the medical and natural image domains (kidney boundaries, NYU-Depth V2, BSDS 500). While the skeletonize algorithm was compared to classical topological skeletons, the validity of our post-processing algorithm was evaluated by integrating the original post-processing methods from six different works. Results Using the state of the art metrics, precision and recall based Signed Distance Error (SDE) and the Intersection over Union bounding box (IOU-box), our results indicate that the SDE metric for these edges is improved up to 2.3 times. Conclusions Our work provides guidance for parameter tuning and algorithm selection in the post-processing of predicted object boundaries.

Influence of End Mill Manufacturing on Cutting Edge Quality and Wear Behavior

One of the decisive factors for the performance of milling tools is the quality of the cutting edge. The latter results from the process control of the individual steps along the tool manufacturing process chain, which generally includes the sintering or pressing of the blanks, grinding, cutting edge preparation, and coating of the tools. However, the targeted and application-specific design of the process steps in terms of high economic efficiency is currently limited by a lack of knowledge regarding the influence of the corresponding process parameters on the resulting cutting edge quality. In addition, there is a lack of suitable parameters that adequately represent the characteristics of the cutting edge microtopography. This publication therefore investigates the influence of manufacturing processes on cutting edge quality and wear behavior of end mills. On this basis, different characterization parameters for the cutting edge quality are derived and evaluated with regard to their ability to predict the wear behavior.