Non-Contact Auxiliary Fixture For Better Machining Of Thin Flexible Workpiece Using Eddy Currents

Thin flexible parts are widely used in the aerospace industry and require a more precise surface finish. The main problem in achieving high-quality product is the vibration induced during machining of thin-walled parts. Clamping these thin parts or using rigid supports for parts, such as for propeller blades, lead to distortion. This issue may be solved using a non-contact auxiliary fixture. The new fixture developed in this research is an eddy current damper for passive control of vibrations in electrically conducting workpieces, using neodymium permanent magnets without any external power source. Two thin aluminum beams with different cross-section and same length were used to test the developed fixture. To increase the overall damping, conducting sheets were attached at the free end of beams. Impact and machining tests were conducted to validate the new fixture. The results showed higher damping and better machining stability leading to enhanced surface quality of the workpiece

The Effect Of Nanoparticle Concentration On Mql Performance When Machining Ti-6Al-4V Titanium Alloy

The main purpose of using cutting fluid during machining processes is to reduce the cutting temperature and friction, and to wash away chips from the cutting zone. However, excessive use of conventional cutting fluid negatively influences human health and environment. Therefore, much research has attempted to improve cutting fluid performance with superior tribological and thermal properties, and to reduce the amount of cutting fluid to minimize machining cost and impact on environment. Recently, Minimum Quantity Lubrication (MQL) technique has been widely investigated as a good alternative to flood coolant. Although MQL improves machining results, its removal heat capability still needs to improve. In this paper, in order to enhance the thermal conductive and viscosity of MQL, nanoparticles were dispersed to make nanofluid coolant. Nanofluids have attracted the attention of investigators due to their good high thermal conductivity and ability to remove heat. In this study, the effect of the cutting speed, feed rate, and nanoparticle concentrations on machining titanium Ti-Al6-V4 alloy were investigated by performing ANOVA analysis. The nanofluid coolant was prepared by adding Aluminum Oxide (Al2O3) nanoparticles to base fluid (vegetable oil) at different weight concentrations (0, 2, and 4%wt).The ANOVA analysis found that the nanoparticle concentrations and feed rate had a significant influence on surface roughness. The tool wear was also observed to be affected by nanoparticle concentration significantly. The nanoparticles concentration had a significant impact on the flank wear as it could improve the thermal conductivity and lubrication properties of the cutting fluid and reduce the coefficient of friction between the tool- workpiece and toolchip. In terms of the effect of nanoparticle concentrations, 4% wt provided better improvements in both surface roughness and tool wear compared to 2% wt concentration and the pure MQL

The Effect Of Minimum Quantity Lubrication On The The Fsw Process Performance

The effect of Minimum Quantity Lubrication (MQL) on performance of Friction Stir Welding (FSW) process for Aluminum Alloy 6061-T651 plates was investigated. MQL was used as a cooling and lubrication medium. Five different levels of rotational speed and three feed speed ranges with and without MQL were tested. The effect of MQL on the mechanical properties of the weld joints was studied throughout means of Ultimate Tensile Strength (UTS) tests. Statistical analyses were run to study the relationship between certain process parameters and response. The results showed that the average UTS of the welds is improved when MQL was applied to most of the process variables. The highest UTS was achieved at spindle speed with 1600 rpm and with feed rate 180 mm/min due to improvement of the grain growth

Machining Ti-6Al-4V Alloy Using Nano-Cutting Fluids: Investigation and Analysis

Minimum Quantity Lubrication nanofluid (MQL-nanofluid) is a viable sustainable alternative to conventional flood cooling and provides very good cooling and lubrication in the machining of difficult to cut materials such as titanium and Inconel. The cutting action provides very difficult conditions for the coolant to access the cutting zone and the level of difficulty increases with higher cutting speeds. Furthermore, high compressive stresses, strain hardening and high chemical activity results in the formation of a ‘seizure zone’ at the tool-chip interface. In this work, the impact of MQL-nanofluid at the seizure zone and the corresponding effects on tool wear, surface finish, and power consumption during machining of Ti-6Al-4V was investigated. Aluminum Oxide (Al2O3) nanoparticles were selected to use as nano-additives at different weight fraction concentrations (0, 2, and 4 wt.%). It was observed that under pure MQL strategy there was significant material adhesion on the rake face of the tool while the adhesion was reduced in the presence of MQL-nanofluid at the tool-chip interface, thus indicating a reduction in the tool chip contact length (TCCL) and reduced seizure effect. Furthermore, the flank wear varied from 0.162 to 0.561 mm and the average surface roughness (Ra) varied from 0.512 to 2.81 µm. The results indicate that the nanoparticle concentration and the reduction in the seizure zone positively influence the tool life and quality of surface finish

Toxicity Analysis of Nano-Minimum Quantity Lubrication Machining—A Review

The lubrication properties of nanoparticles are of great interest to the manufacturing industry and led to the development of the nano-minimum quantity lubrication (NMQL) cooling strategy. To evaluate the sustainability characteristics of nano-minimum quantity lubrication, apart from analyzing the benefits of increasing machining efficiency, it is also essential to evaluate the potential detrimental effects of nanoparticles on human health and the environment. Existing literature provides substantial data on the benefits of nano-minimum quantity lubrication machining. However, the current literature does not provide researchers in the machining sector a comprehensive analysis of the toxicity of the nanoparticles used in nano-minimum quantity lubrication. This study aims to provide a comprehensive review that addresses the toxicity levels of the most frequently used nanoparticles in NMQL machining. To understand the impacts of nanoparticles on the human body and the environment, in vitro studies that evaluate the nanoparticles’ toxicity on human cells and in vitro/in vivo studies on other living organisms are considered. The results from toxicity studies on each of the chosen nanoparticles are summarized and presented in chronological order. The reviewed studies indicate transition metal dichalcogenides (MoS2 and WS2) exhibit very low toxicity when compared to other nanoparticles. The toxicity of hBN and AL2O3 nanoparticles varies depending on their lengths and crystalline structures, respectively. In conclusion, a chart that maps the toxicity levels of nanoparticles on seven different human cell lines (human lung epithelial cells (A549), human bronchial epithelial cells (Nl-20), AGS human gastric cells, human epidermal cells (HEK), human liver-derived cells (HepG2), human endothelial cells and human peripheral cells), representing exposures by inhalation, ingestion and dermal contact, was developed for easy and quick insights. This is the first attempt in open literature to combine the results of the experimental investigations of nano-minimum quantity lubrication cooling and the toxicity studies of nanoparticles, allowing researchers to make informed decisions in the selection of the most sustainable nanoparticles in the nano-minimum quantity lubrication machining process

Sustainability Assessment during Machining Ti-6Al-4V with Nano-Additives-Based Minimum Quantity Lubrication

The implementation of sustainable machining process can be accomplished by different strategies including process optimization and selection of the proper lubrication techniques and cutting conditions. The present study is carried out from the perspective of a sustainability assessment of turning Ti-6Al-4V by employing minimum quantity lubrication (MQL) and MQL-nanofluid with consideration of the surface quality, tool wear, and power consumption. A sustainability assessment algorithm was used to assess the cutting processes of Ti-6Al-4V alloy under a minimum quantity of lubrication–nanofluid to estimate the levels of sustainable design variables. The assessment included the sustainable indicators as well as the machining responses in a single integrated model. The sustainable aspects included in this study were; environmental impact, management of waste, and safety and health issues of operators. The novelty here lies in employing a comprehensive sustainability assessment model to discuss and understand the machining process with MQL-nanofluid, by not only considering the machining quality characteristics, but also taking into account different sustainability indicators. In order to validate the effectiveness of the sustainability results, a comparison between the optimal and predicted responses was conducted and a good agreement was noticed. It should be stated that MQL-nanofluid showed better results compared to the cutting tests conducted under using classical MQL

Expanding Poly(lactic acid) (PLA) and Polyhydroxyalkanoates (PHAs) Applications: A Review on Modifications and Effects

The high price of petroleum, overconsumption of plastic products, recent climate change regulations, the lack of landfill spaces in addition to the ever-growing population are considered the driving forces for introducing sustainable biodegradable solutions for greener environment. Due to the harmful impact of petroleum waste plastics on human health, environment and ecosystems, societies have been moving towards the adoption of biodegradable natural based polymers whose conversion and consumption are environmentally friendly. Therefore, biodegradable biobased polymers such as poly(lactic acid) (PLA) and polyhydroxyalkanoates (PHAs) have gained a significant amount of attention in recent years. Nonetheless, some of the vital limitations to the broader use of these biopolymers are that they are less flexible and have less impact resistance when compared to petroleum-based plastics (e.g., polypropylene (PP), high-density polyethylene (HDPE) and polystyrene (PS)). Recent advances have shown that with appropriate modification methods—plasticizers and fillers, polymer blends and nanocomposites, such limitations of both polymers can be overcome. This work is meant to widen the applicability of both polymers by reviewing the available materials on these methods and their impacts with a focus on the mechanical properties. This literature investigation leads to the conclusion that both PLA and PHAs show strong candidacy in expanding their utilizations to potentially substitute petroleum-based plastics in various applications, including but not limited to, food, active packaging, surgical implants, dental, drug delivery, biomedical as well as antistatic and flame retardants applications

Implementation of Sustainable Vegetable-Oil-Based Minimum Quantity Cooling Lubrication (MQCL) Machining of Titanium Alloy with Coated Tools

The lubrication capacity and penetration ability of the minimum quantity cooling lubrication-based strategy is linked with lubrication specific parameters (oil flow rates and air pressure), cutting conditions, and chip formation. It points out the complex selection involved in the MQCL-assisted strategy to attain optimal machining performance. Lubrication during metal cutting operations is a complex phenomenon, as it is a strong function of the cutting conditions. In addition, it also depends on the physical properties of the lubricant and chemical interactions. Minimum Quantity Lubrication (MQL) has been criticized due to the absence of cooling parts; MQCL is a modified version where a cooling part in the form of sub-zero temperatures is provided. The aim of this paper was to investigate the influence of different lubrication flow parameters under minimum quantity cooling lubrication (MQCL) when machining aeronautic titanium alloy (Ti6Al4V) using Titanium Aluminum Nitride—Physical Vapor Deposition (TiAlN-PVD) coated cutting inserts. The machining experiments on the MQCL system were performed with different levels of oil flow rates (70, 90, and 100 mL/h) and the performance was compared with the conventional dry cutting and flood cooling settings. A generic trend was observed that increasing the oil flow rate from 70—mL/h to 100 h/h improved the surface finish and reduced thermal softening at a low feed of 0.1 mm/rev. The results revealed that many tool-wear mechanisms such as adhesion, micro-abrasion, edge chipping, notch wear, built-up edge (BUE), and built-up layer (BUL) existed

Implementation of Sustainable Vegetable-Oil-Based Minimum Quantity Cooling Lubrication (MQCL) Machining of Titanium Alloy with Coated Tools

The lubrication capacity and penetration ability of the minimum quantity cooling lubrication-based strategy is linked with lubrication specific parameters (oil flow rates and air pressure), cutting conditions, and chip formation. It points out the complex selection involved in the MQCL-assisted strategy to attain optimal machining performance. Lubrication during metal cutting operations is a complex phenomenon, as it is a strong function of the cutting conditions. In addition, it also depends on the physical properties of the lubricant and chemical interactions. Minimum Quantity Lubrication (MQL) has been criticized due to the absence of cooling parts; MQCL is a modified version where a cooling part in the form of sub-zero temperatures is provided. The aim of this paper was to investigate the influence of different lubrication flow parameters under minimum quantity cooling lubrication (MQCL) when machining aeronautic titanium alloy (Ti6Al4V) using Titanium Aluminum Nitride—Physical Vapor Deposition (TiAlN-PVD) coated cutting inserts. The machining experiments on the MQCL system were performed with different levels of oil flow rates (70, 90, and 100 mL/h) and the performance was compared with the conventional dry cutting and flood cooling settings. A generic trend was observed that increasing the oil flow rate from 70—mL/h to 100 h/h improved the surface finish and reduced thermal softening at a low feed of 0.1 mm/rev. The results revealed that many tool-wear mechanisms such as adhesion, micro-abrasion, edge chipping, notch wear, built-up edge (BUE), and built-up layer (BUL) existed

Influence of Bio-Fertilizers and Addition Methods on Growth, Yield and Quality of Sweet Pepper Under Green House

The effect of some biofertilizers and addition methods on growth, yield, and quality of sweet pepper were studied under greenhouse conditions. This research was conducted at ALLatifia Research Station(Located 35 km south of Baghdad), Agricultural Research Directorate, Baghdad- Iraq, during season 2016. The factors were methods of adding biofertilizers (A) included added to seeds (A1) and added to transplants (A2) and bio-fertilizers (T) included without adding any biofertilizers as control(T0), Pseudomonas fluorescence (T1), Azospirillim brasilense (T2), Bacillus subtillus (T3) and Azotobactor chroococcum (T4). Results showed a significant increase in plant height for treatment of Azotobacter chroococcum which recorded (79.00 cm) compared with (65.00 cm) in the control treatment. There is no significant influence of biofertilizers treatments in leaf area dcm2. Moreover, the treatment of Azotobacter chroococcum showed a significant increase for plant yield and total yield which recorded (1344.00 gm plant-1 and 1512.00 kg green house-1) respectively in comparison with the control treatment which recorded( 880.00 gm plant-1 and 989.00 kg green house-1) respectivel