Papers by Keyword: Quality

Abstract: Transverse (charge) welds form during billet transitions in aluminium extrusion when incoming material progressively replaces residual metal inside the die, defining the length of extrudate that must be scrapped. This study aimed to quantify charge weld evolution under industrially relevant conditions that are often underestimated in scrap length assessment, including multi-cavity flow imbalance, non-symmetric multi-profile placement, and billet-to-billet thermal stabilisation effects. Three case studies were analysed using finite element simulation in QForm UK: (i) the International Extrusion Benchmark 2023 multicavity die producing three hollow tubes with intentionally varied port and bearing designs, (ii) an industrial two-profile die with translated (non-mirrored) profile positioning to avoid post-extrusion rotation, and (iii) a complex industrial profile extruded over multiple consecutive billets. The benchmark study demonstrated strong agreement between simulation and experimental charge weld evolution for two profiles, supporting the reliability of the predicted cavity-dependent differences driven by port volume. In the translated two-profile configuration, the charge weld cut length required for full purity increased from 1674 mm to 1940 mm (+16.0%), and by +15.9% under the 95% industrial criterion (1458.1 mm vs 1690.7 mm). Billet-to-billet variability was substantial, with charge weld length increasing by +70.1% from the first to the fifth billet (2819.0 mm to 4791.7 mm), before stabilising. Overall, the results show that charge weld length is governed by residence-time differences through ports and flow channels, requiring profile-specific assessment and consideration of process stabilisation. In this context, FE simulation provides an effective means to localise the mixed zone and to support die optimisation strategies aimed at reducing scrap.

Abstract: The chemical characterization of the Ghis-Nekor aquifer has attracted significant attention from researchers in Morocco. It is a crucial indicator of the environmental situation and the socio-economic development of this Moroccan region. Indeed, it helps decision makers to conduct a conscious and sustainable management. The primary objective of this study is to investigate the origin of salinity using isopoly elements such as Stronstium and Bromide and to evaluate the physicochemical quality of groundwater in the Ghis-Nekor aquifer region and to determine the sources of pollution in order to establish maps of the qualities of the Ghis-Nekor water table. For this reason, of Ghis-Nekor aquifer 19 samples were examined during the month of July 2023, in terms of isotopic elements such as bromine (Br) and strontium (Sr) et tantalum (Ta) (03 samples), and in terms of physico-chemical parameters such as pH, temperature, electrical conductivity (EC), Chlorides, Nitrates, Ammonium, Nitrite, Sulfates, Sodium, Potassium, Bicarbonates, Calcium, orthophosphates and Magnesium . The spatial distribution of the results was visualized through thematic maps generated using a Geographic Information System (GIS), offering crucial insights for decision-making processes related to water resource management in the region.The water temperature varies between 15.1 and 49°C. The pH is close to neutral, varying between 6.65 and 7.86. The waters are classified into three distinct chemical facies: chlorinated and sulfated calcic-magnesium facies, bicarbonated calcic-magnesium facies, and chlorinated sodium-potassium facies.The degradation of water quality in the aquifer of the basin of Ghis-Nkour could have geological and anthropogenic origins. The analysis of bromide and strontium contents allows to discriminate the origin of salinity anomalies. Molar ratios such as Cl/Br, Br/Cl, and Sr/Ca are employed to distinguish areas influenced by geological factors, such as the leaching of salt formations and facies, from those impacted by anthropogenic activities.

Abstract: Gear wear is the main factor affecting their performance and service life. In addition to the accuracy of production, the quality of the material from which the gears are made also depends on the degree of wear. The article compares the material properties of gears of JAWA motorcycle transmissions. In addition to the original gears, produced at that time in Czechoslovakia, the market also offers gears that are produced today, originally from the Czech Republic and Taiwan. Since the only comparable indicator is their price difference, the question arose whether the new variants can compete with the original part in terms of quality of workmanship. For this finding, the gears were subjected to wear tests and determination of the hardness of the material with the devices intended for this. In this way, valuable data will be obtained that will contribute to a better understanding of the performance and lifetime of these components. The quality of workmanship as well as the price are factors that should always be considered before the final selection of the item.

Abstract: Progressive electrical discharge machining technology is characterized by a high degree of quality of the machined surface. The high achieved quality of the machined surface not only in terms of roughness parameters but also in terms of geometric shape is practically a matter of course with this machining technology. Nevertheless, in certain specific cases, geometric deviations of the shape occur, even when the most modern and highly sophisticated electrical discharge equipment are used. One of the frequently occurring geometric inaccuracies of the shape when applying progressive electrical discharge machining technology with a wire tool electrode is the deviation of circularity. Therefore, the aim of the conducted experimental research was to identify these shortcomings in the first place and also to describe in which specific cases these deviations occur. Subsequently, based on the obtained results of experimental measurements, propose appropriate measures for their elimination or at least their minimization.

Abstract: Carbide machining process brings a whole range of problems in practice. This mainly concerns problems associated with their machinability and the economy of the applied machining technology. Because of these problems, it is often not possible to use traditional production technologies when machining them. However, progressive machining technologies achieve relatively good results. However, even with progressive technologies, the problem with the overall efficiency of the machining process remains. Therefore, experimental research was carried out, the aim of which was to obtain relevant data regarding the quantification of qualitative indicators of the machined surface during the machining of hard metals through progressive electrical discharge technology in relation to the overall economic efficiency of the machining process. As part of the conducted experimental research, partial data of individual elements were obtained on the basis of which complex conclusions were drawn in mutual contexts. Subsequently, complex data regarding the effectiveness of the applied electrical discharge process in the machining of hard metals were summarized.

Abstract: UD. Pak Suandi is one of the UDs that produces and sells bricks. Many factors influence the quality of bricks, namely human resources, composition, and processing of raw materials. Brick making sometimes does not match the desired quality, there are often defects/cracks in the bricks. The method used in this research is the Taguchi method, where Taguchi is used to design efficient and effective experiments in identifying factors that influence brick quality, such as brick compressive strength, as well as to determine optimal settings of production parameters with the aim of maximizing brick quality. The results of this research show that the factors that have a significant influence are factors A (Clay) and D (Laban Tree Ash). The high SNR ANOVA value shows this. The optimal concentration settings are 1.40 kg of Clay, 45 ml of Water, 13 grams of Palm Ash and 14 grams of Laban Tree Ash. Where with the composition design, a compressive strength value of 9.73 MPa is obtained. The compressive strength obtained increased by 6.03 Mpa from the company's standard composition of 3.70 Mpa.

Abstract: The present research aimed to evaluate the effect of nickel-based electrochemical metallization (EMNi) on the quality and performance of electric motor components, compared to high-velocity oxy-fuel (HVOF) thermal spray coating, the most widely used coating in the mining industry. The experiment was conducted using motor components comprised of 4340 VCN steel, 4140 VCL steel, 1045 steel, and stainless steel, which underwent both treatments. The surface temperature of the components was monitored during the processing stage, followed by evaluations of their Rockwell hardness (HRC) and surface characteristics (taper, ovality, parallelism, finish, wear) at the onset (day 0) and after 2 years of use the results indicate that EMNi delivers electric motor components with superior finishes and extended warranty and service life in comparison to HVOF.

Abstract: Currently, the manufacturing industries play an important part in the global economy. I t is critical for the industries to maintain the high standards of goods and products. Various machines / systems have been developed for determining dimensional stability or the lack of filling in a casting product, thereby rejecting the defective products. The existence of the casting product is detected using an infrared or ultrasonic sensor. When a product arrives along the conveyer, the sensor can detect its measurements. If the product has the necessary proportions and dimensions, it is moved to the accepted bin; otherwise, it is denied by a pneumatic actuator and placed in the rejecter bin. Eventually, a profound learning model that categorizes into two different categories has been studied to automate the manual inspection procedure in the casting failure system. This automated casting fault separation machine is accurate, reliable and low cost which makes it suitable for small scale industries with easy segregation of high quality products. The objective of this paper is to review the various automatic systems developed for separating casting fault.

Abstract: Additive manufacturing processes build three-dimensional objects usually following a layer-upon-layer strategy. An interesting feature of this strategy is that each layer could be inspected before the next one is deposited. On-machine integration of layerwise inspection systems would not only allow for early characterization of the dimensional and geometric quality of the part, but also for the detection of intralayer defects. Contact image sensors (CIS), such as those used in desktop flatbed scanners, could be used for this purpose since they would provide bi-dimensional digital images of the whole layer and its neighborhood. CIS images combine high resolutions with a reduced acquisition time. In this work, a material extrusion (MEX) additive manufacturing system, with layerwise inspection capabilities is proposed. The system has been equipped with the CIS that Epson uses in its Perfection V39 flatbed scanner. The sensor provides two analog output signals, each one consisting on 2584 voltage levels, that represent the amount of light reflected by the material. This analog information is sent to a parallel AD converter, where an 8-bit encoding is assigned to each one of the pixels on the digitized image. To overcome microcontroller-related problems, a Zynq®-7000 system-on-chip (SoC) has been used. This SoC integrates an ARM® based processor, with the hardware programming of a field programmable gate array (FPGA). This architecture ensures an accurate and controlled readout of the various AD converters. The resultant digital image of each layer could then be then processed using different algorithms to detect defects, extract the geometry of the layer contour and characterize the dimensional and geometric quality of the object. In the example provided, a forced error consisting on 0.2 mm height local deviations, caused by a variation in extrusion temperature, was identified from 2D grayscale images obtained with the CIS sensor.

Abstract: Welding processes are commonly used in the industry for the manufacture of large parts or due to their complex geometry that does not allow the part to be manufactured as a whole. Nevertheless, the union can show worst mechanical properties than the rest of the piece, affecting negatively its service behavior, so it is necessary evaluate weald seam to ensure the correct process application. Electrical welding operations are commonly used due to the reduced equipment size or their possibilities application in numerous metallic materials. Notwithstanding, different variables have to be taken into account during the metal deposition, as intensity or speed deposition, among others. Weald seam geometrical evaluation is usually utilized to validate the union surface conditions. Despite this, surface irregularities caused during the process make its difficult to measure correctly with conventional equipment. However, laser profilometry is a non-contact technique that can be used to generate 3D profile of weald seam, facilitating its measurement with high accuracy. Therefore, in this work an initial analysis of the influence of material deposition speed and arc welding intensity on the weald seam geometry will be carried out using a laser profilometry equipment. In addition, to ensure a correct information acquisition, the laser profilometer requires a constant speed movement in relation with the weald seam analyzed, so new equipment has been manufactured, using additive manufacturing techniques, to support the profilometer throughout the information acquisition process.