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Particles emitted during manufacturing processes such as polishing can represent a serious danger for the environment and for occupational safety. The formation mechanisms responsible for these dust emissions include chip formation, friction at the tool/workpiece and chip/tool interfaces, shearing and cutting. These mechanisms thus depend on workpiece and tool properties, as well as the polishing conditions. In the case of granite polishing, particle emissions during polishing can contain chemical compounds such as silica, which represent harmful health risks for the worker. It is therefore important to characterize the particles emitted and to search for possible interactions between the particles (size and composition) and the machining conditions in order to find ways of reducing emissions at the source. In this study, an investigation was undertaken to characterize the particles emitted during granite polishing as a function of polishing conditions, type of granite, and abrasive grit sizes used. Scanning electron microscopy (SEM) was employed for particle morphology characterization and particle grain size and chemical composition were evaluated using X-ray diffraction (XRD) and energy dispersive X-ray (EDX) techniques, respectively. Results show that the influence of polishing speed and feed rate on particle emission depends mainly on the granite type used, providing useful information for controlling the polishing procedure, and thereby dust emission. [ABSTRACT FROM AUTHOR]

Clean machining is gaining ground as one of the crucial issues in future manufacturing. Many machining industries are looking for alternative solutions to wet machining because of the costs of the latter, including environmental costs, as well as its impact on occupational health and safety. Dry machining is being proposed, but in most conditions, the cutting tool wears out quicker, leading to part quality deterioration and increased machining costs. Minimum quantity lubrication (MQL) machining is also proposed to maintain a reasonable tool life and limited cost, as compared to the situation with flood or wet machining. Both the MQL and dry machining methods, however, are susceptible to the generation of aerosols containing metallic particles that can be detrimental to occupational health and safety. Minimizing particle emissions is of prime importance since these can have serious consequences on the operator's health. They have been seen to be at a minimum at two specific cutting ranges. In this study, investigations are done to examine the effect of lubrication (dry and MQL) during the turning of the 7075-T6 aluminum alloy. The performance indexes studied are the surface roughness, the chip thickness, and aerosol generation. [ABSTRACT FROM AUTHOR]

In the manufacturing industry, cutting tool failure is a serious event which causes damage to the cutting tool and reduces the quality of the product, which increases the cost of production. A reliable, intelligent, tool wear monitoring system is required in the metal cutting manufacturing process to mitigate these negative effects. This study presents a model-based approach for tool wear monitoring based on an adaptive neuro-fuzzy inference system (ANFIS) for a cold-finished steel bar 1215 turning process. A three-input cutting force (Fx, Fy and Fz) and single-output (tool flank wear) model was designed and implemented using the ANFIS approach. The forces were measured using a piezoelectric dynamometer and data acquisition system. Flank wear was also monitored using a tool maker's microscope. The model prediction results show that it is accurate enough to perform online monitoring of the turning process and can detect wear while operating. [ABSTRACT FROM AUTHOR]

Sustainable manufacturing regulations are pushing manufacturing towards decreasing of manufacturing hazards including microparticles and ultrafine particles. Machining process such as milling produces dust that can be harmful for operators' health. The emission of this dust depends on workpiece materials (microstructure, mechanical properties) and machining conditions. The aim of this paper is to determine the effect of the microstructure and machining conditions on dust emission during dry milling of Al-20Mg2Si-2Cu metal matrix composite with addition of bismuth (Bi) and barium (Ba). Experiments were carried out using dry CNC milling by uncoated carbide tools. An aerodynamic particle sizer (APS) and a scanning mobility particle sizer (SMPS) were used to measure microparticles and ultrafine particles emission, respectively. It was found that the addition of 0.4 wt% Bi and 0.2 wt% Ba changed Mg2Si particle size and improved the hardness of composite. In addition, ultrafine particle number concentration, specific area concentration and mass concentration decreased with the addition of modifiers. It is also confirmed that cutting conditions and microstructure of workpieces have a direct effect on dust emission during the milling process. [ABSTRACT FROM AUTHOR]

Edge finishing is a shaping process that is extremely important in the granite and marble processing industries. It does not only shape the edge but also makes it shiny and durable. However, this process generates dust (fine and ultrafine particles) that can have a significant impact on air quality in the workshop and can put workers' health at risk. While environmental requirements and occupational health and safety regulations are becoming increasingly stringent, at the same time, industries must continue to produce quality parts at competitive prices. The purpose of this study was to examine the surface quality, the cutting forces, and the emission of fine (FP) and ultrafine (UFP) particles during wet and dry edge finishing of granite edges as a function of the machining parameters and abrasive grit sizes. Three machining operations were investigated: roughing, semi-finishing, and finishing, using diamond abrasives (with grit sizes 45, 150, 300, 600, 1500, and 3000). The experiments were carried out on two granites, one being black and the other white. The tested spindle speeds ranged from 1500 rpm to 3500 rpm and the feed rates from 500–1500 mm/min. It was found that roughing operations produce more fine particles while finishing operations produce more ultrafine particles. These particle emissions, as well as the part quality and the cutting forces are strongly dependent on cutting speed and on the grit size of the abrasive used. [ABSTRACT FROM AUTHOR]

This article presents the influence of machining conditions on typical process performance indicators, namely cutting force, specific cutting energy, cutting temperature, tool wear, and fine dust emission during dry milling of CFRPs. The main goal is to determine the machining process window for obtaining quality parts with acceptable tool performance and limited dust emission. For achieving this, the cutting temperature was examined using analytical and empirical models, and systematic cutting experiments were conducted to assess the reliability of the theoretical predictions. A full factorial design was used for the experimental design. The experiments were conducted on a CNC milling machine with cutting speeds of 10,000, 15,000, and 20,000 rpm and feed rates of 2, 4, and 6 µm/tooth. Based on the results, it was ascertained that spindle speed significantly affects the cutting temperature and fine particle emission while cutting force, specific cutting energy, and tool wear are influenced by the feed rate. The optimal conditions for cutting force and tool wear were observed at a cutting speed of 10,000 rpm. The cutting temperature did not exceed the glass transition temperature for the cutting speeds tested and feed rates used. The fine particles emitted ranged from 0.5 to 10 µm aerodynamic diameters with a maximum concentration of 2776.6 particles for those of 0.5 µm diameters. Finally, results of the experimental optimization are presented, and the model is validated. The results obtained may be used to better understand specific phenomena associated with the milling of CFRPs and provide the means to select effective milling parameters to improve the technology and economics of the process. [ABSTRACT FROM AUTHOR]

New biocomposites are increasingly being developed and applied in engineering and manufacturing. The reinforcement type used in biocomposite is one of the major factors that greatly affect the machinability of biocomposite. This study investigated the drilling of two biocomposites (polypropylene-based biocomposite reinforced with biocarbon M1 (30 wt% biocarbon + PP/POE/MAPP) and chopped miscanthus fibers M2 (30 wt% miscanthus + PP/POE/MAPP)). A full factorial design was used for this study. The effects of drilling parameters and reinforcement types on surface roughness, thrust force, specific cutting energy, fine particles, and ultrafine particle generation were measured and analyzed. The results show that the thrust force and specific cutting energy during drilling of biocomposite M1 is bigger than that of biocomposite M2 under the same cutting conditions. However, the surface roughness and fine dust emitted when drilling biocomposite M1 are smaller than those from biocomposite M2, respectively. The reinforcement types of biocomposite, cutting parameters and drill diameter greatly affected fine particles emission. Meanwhile, the cutting conditions are not statistically significant for ultrafine particle generation during dry drilling of both biocomposites. [ABSTRACT FROM AUTHOR]

The machinability of composite materials depends on reinforcements, matrix properties, cutting parameters, and on the cutting tool used (material, coating, and geometry). For new composites, experimental studies must be performed in order to understand their machinability, and thereby help manufacturers establishing appropriate cutting data. In this study, investigations are conducted to analyze the effects of cutting parameters and drill bit diameter on the thrust force, surface roughness, specific cutting energy, and dust emission during dry drilling of a new hybrid biocomposite consisting of polypropylene reinforced with miscanthus fibers and biochar. A full factorial design was used for the experimental design. It was found that the feed rate, the spindle speed, and the drill bit diameter have significant effects on the thrust force, the surface roughness, and the specific cutting energy. The effects of the machining parameters and the drill bit diameter on ultrafine particles emitted were not statistically significant, while the feed rate and drill bit diameter had significant effects on fine particle emission. [ABSTRACT FROM AUTHOR]