Papers by Keyword: Accuracy

Abstract: Flume is an artificial open channel construction tool that holds water in the desired amount and is used as an observation, measurement or test equipped with a water flow that can be controlled and the slope of the channel can be adjusted as needed. The purpose of this study was to obtain a comparison of the accuracy of using several velocity measuring instruments available in the hydraulics laboratory on the experimental flume. There are two measurement methods used in this study, namely the Measured/Aqtual Discharge Method and the Flow Velocity Method. Measurement of flow velocity to obtain discharge carried out in this study using a current meter flow watch (FW), electromagnetic current meter (ECM), Portable velocity meter 0.01-4.0 m/s LS300 A). method to get accuracy, refers to the current meter discharge value with the measured discharge value. From the results of the study it can be concluded that the Measurement Accuracy of flow watch (FW) = 94.23%, electromagnetic current meter (ECM) = 5.90%, and Portable velocity meter 0.01-4.0 m/s LS300 A = 100.23%, The results of verification and validation of measurement accuracy between actual discharge and discharge using velocity measuring instruments show that the value of discharge using Portable velocity meter 0.01-4.0 m/s LS300 A is close to the aqtual discharge value.

Abstract: This paper studies the effect of the direct energy deposition (DED) process parameters varying within 20% on the geometric accuracy and formation of residual stresses in the products. In the course of the study, an experiment was carried out according to Taguchi's L9 plan to fabricate samples by varying the laser travel speed, effective focusing distance, feed rate of metal powder composition, and process pause, which were then compared with the rates of geometry change and crystal lattice distortion. The obtained results were subjected to statistical analysis using correlation, regression and factor analysis to determine the influence and significance of factors. As a result, correlations between the process parameters and sample characteristics were identified. As correlation and factor analysis showed, a change in process factors within 20% does not significantly affect most of the quality parameters, except for the level of residual stresses. Geometric and strain parameters are weakly correlated with each other, but no statistically significant correlations were found between them. The analysis of variance showed that the fusion rate and powder flow rate have the greatest influence on the geometric accuracy parameters. These factors have the most significant statistical influence on the response, indicating the importance of controlling these parameters to achieve high geometry accuracy. Regression analysis allowed to obtain adequate models of residual stress level. It was found that the model for residual stress level by planes (200) is more reliable than the model for residual stress level by crystallographic plane (111). The obtained data allow to optimize the DED process in order to achieve a given geometric accuracy and reduce residual stresses in the manufactured products.

Abstract: In the work, the design of the tool – boring bar for parallel machining of conical surfaces and threads in coupling-type parts with opposite directions, same inclination, coaxial conical surfaces and threads is given, and their generalized design features are presented for the machining of couplings of different types and sizes. With the application of the designed tool - boring bar to machining of inner surfaces of couplings, their machining accuracy, especially accuracy of coaxiality of threads, thus the load-carrying capacity of the couplings increases, the technological cost of their production is reduced, and the efficiency of their use is ensured.

Abstract: The development of lithium batteries as an energy storage system is getting higher equal to the development of eco-friendly energy needs. However, lithium batteries have disadvantages in electrical and temperature interference. Series and parallel configuration causes voltage imbalance and leads to degradation performance of the battery. The focus of the research is the development of BMS with voltage monitoring and balancing features for the 12-series battery pack configuration. Monitoring can be done by observing electrical parameters, are cell voltage and battery temperature. The results of the simulation and modeling of BMS and Lithium-ion Battery show that the flat-zone voltage on the LFP UNS battery is in the 10-90% SoC range (generally SoC 20-80%), and the characteristics of lithium battery are current affects the battery voltage curve (high current causes a high voltage drop), while temperature affects the internal resistance (low temperature causes an increase in internal resistance). The BMS hardware monitoring test shows the accuracy and precision of the voltage sensor at 99.7064% and 99.9998%, while the temperature sensor performs the accuracy and precision of 95.4909% and 100%, respectively. The passive balancing method with Switched Shunt Resistor shows a nominal balancing current of about 170mA with a 20mV voltage drop.

Abstract: Polymers have been around for a while now, and for the time being they play a fundamental role in our society. As time passes, the number of polymer-based items increases. Thermoforming is a conventional polymer manufacturing process with high potential. This paper explores the surface quality of 3D printing dies after being used in a thermoforming process. A polylactic acid (PLA) die was printed using a Fused Deposition Modelling (FDM) The polymeric blanks formed were Polycarbonate (PC) and Polyvinyl chloride (PVC) sheets of 1.5 mm. The results reveal the effects of the temperature, the thermoforming process time and vacuum time on the wear of the top surface dis not surpass 1mm in the worst zone, and does not affect the polymeric formed sheets.

Abstract: Dimensional accuracy is critical in industrial applications and can limit the use of Fused Filament Fabrication FFF. The printing steps required in material extrusion: pre-processing, processing, and post-processing influence dimensions. While processing and post-processing steps lead to inaccuracies due to machine limitations, dimensional errors from the pre-processing step are motivated by inadequate representations and mathematical approaches. This work studies if the slicing approach can contribute to dimensional deviations. It is considered a pyramid sample with four different wall angles to check this hypothesis. Next, its CAD model is sliced using three approaches: inclusive, middle, and exclusive. The resulting gcodes were compared against the theoretical pyramid sections to quantify deviations. It is worth mentioning that each slicing approach shows a different deviation curve along the printing direction and the wall angle. These results highlight the slicing strategy as a potential source of dimensional inaccuracies. Finally, three sample cases (one for each slicing strategy) are printed, measured, and compared using a 3D scanner and conventional measurements to support the numerical examples.

Abstract: Additive Manufacturing (AM) technologies, also known as 3D printing, are increasingly used to produce usable and appealing end products. Besides allowing greater design freedom, 3D printing can increase material efficiency and drastically reduce production time. However, processes are still lacking in the quality of products. Among dozens of parameters that can influence the printing process, the study analyses the impact of the printing orientation (PO) on the product's geometrical accuracy and the process's overall efficiency. An experimental analysis has been designed and executed. A Fused Deposition Modelling (FDM) machine has been used to print the specimens. In particular, the experimental results showed the influence of PO on the geometrical characteristics of the specimens (bending angle, torsion angle, deviations, flatness tolerance and thickness). Moreover, the variability of production time, cost and resource consumption by varying PO has been investigated. As expected, the worst geometrical performance is shown by upright specimens. Furthermore, the ANOVA analysis underlines that only the orientation of the specimen with respect to the Z-axes (flat, on-edge and up-right) is statistically significant for the geometrical accuracy of the specimens. The method ELECTRE I has been used as Multi Criteria Decision-Making Method to rank the build configurations according to the resulting product's geometrical accuracy, the process performance and decision-maker’s priorities.

Abstract: Digital manufacturing is one of the pillars of Industry 4.0, additive manufacturing is certainly evolving very quickly, with more and more technologies being developed and materials being applied to this production area. However, with this growth and the capacity associated with this type of processes, it is extremely important to understand these processes, so that they can respond quantitatively and qualitatively to market needs. The present work intended to contribute to the improvement of the metal binder jetting process by simulating the manufacturing process of a proposed part, using the Simufact™ software and Desktop Metal software. After validating the parts with manufacturing with Binder jetting additive process. Subsequently, the metrological inspection and analysis of the respective results were carried out. Simulations were carried out for different values of powder size and density of the green part to assess their impact on the quality of the final part. The parts were produced in 17 – 4PH steel using a Shop System Desktop Metal machine. Were produced 5 parts with the following parameters, part (A) model with compensation obtained by Desktop software, part (B) model compensated by the Simufact additive software with 20% scale, part (C) model with scale 1: 1.2, part (D) model obtained by the Simufact additive software and part (E) model without scale. The measurements for the dimensional analysis were made with a digital caliper, while for the geometric analysis, measurements were made on a CMM machine.The simulations revealed smaller errors for larger granule sizes and also for larger green part densities. The inspection of the produced part, on the other side, exposed greater dimensional inaccuracy in X and less in Z direction. It also showed that, for the same element of the part, there is still a relationship between the ratio of the measured dimensions and the ratio of the deviations obtained. The results also showed that parts simulated by two software’s (A and D) are the ones with the best final quality, they presented smaller dimensional and geometric deviations in relation to the proposed model. The highest tolerance grades of these parts were in ISO standard IT15 and IT14 for part D and part A respectively.

Abstract: This paper describes an approach extended from Ritz method to analyze the free vibration of thin isotropic annular plates in good accuracy, and presents comprehensive lists of natural frequencies of the plate for all possible sets of classical boundary conditions. Analytical process is developed to introduce the boundary index that allows to accommodate any sets of free, simple supported and clamped edges along inner and outer boundary of the plate. Convergence and comparison studies are made to demonstrate numerical accuracy in the frequency parameters. Results are summarized for nine sets of boundary conditions and six different ratios of (inner radius)/(outer radius), and are intended to serve for uses of design data and comparison in relevant future papers.

Abstract: The greatest threat to humanity is water pollution. It causes affliction to animals, plants, etc. To avoid the problem in the transportation sector, we need to foretell water standards from pollution using machine learning methods. monitoring and forecasting the value of water has become a vital area to research. The goal is to examine machine learning methods for water quality forecasting by predicting the results to the best accuracy. Dataset is analysed by Supervised Machine Learning Technique (SMLT) to bag a number of details such as, variable identification: uni-variate analysis, bi-variate analysis and multivariate analysis, lost quantity treatment and data validation analysis, data purification / preparation and data detection will be performed on the dataset. The analysis provides a clean guide to examine the sharpness of the model parameters in relation to fulfilment in predicting water standard by calculating its efficiency. To offer a method to accurately predict the Water Quality Index (WQI) value by predicting the results in the form of accuracy from comparing supervised classification machine learning algorithms. Furthermore, to correlate and canvas the effectiveness of various algorithms from the given dataset with evaluation of classification report, confusion matrix, categorizing data from priority and the result shows that the performance of the suggested algorithms that can be compared with Accuracy which is done by evaluating Precision, Recall and F1 Score of the algorithm.