scholarly journals Minimum Quantity Lubrication (MQL) and its Effect on Tool Wear During Miniature Drilling :an Experimental Study

Author(s):  
Norsalawani Binti Mohamad ◽  
Rubina Bahar

Miniature drilling is widely used in industries including electronics and reconstructive surgeries to create small sized holes. Chip removal and effective supply of coolant are the two limiting factors that make the process more complex compared to other meso scale machining processes and also contribute to the tool wear. The tool wear in the process is mainly caused by the interaction, motion and chip production between the tool and work piece. Uniform supply of coolant must be ensured to reach the drilled cavity to keep the tool wear to a minimal level. This study includes experimental investigation of the tool condition after applying Minimum Quantity Lubrication (MQL) system as a greener approach as the name indicates. The tool condition with MQL has also been compared with dry and flood cooling. Two different types of drill bit materials (High Speed Steel and Carbide) have been tested under same experimental condition to drill through Aluminum Alloy 6061 and it has been found that overall performance in terms of tool condition after applying MQL was better compared to the other two methods. The overall wear propagation area was measured for both the conditions. It was seen, the wear propagation covered minimal area with MQL while for flood and dry condition wear was spread over a bigger area on flank. 

Author(s):  
Pushparghya Deb Kuila ◽  
Shreyes Melkote

Laser-assisted micromilling is a promising micromachining process for difficult-to-cut materials. Laser-assisted micromilling uses a laser to thermally soften the workpiece in front of the cutting tool, thereby lowering the cutting forces, improving the dimensional accuracy, and reducing the tool wear. Thermal softening, however, causes the workpiece material to adhere to the tool and form a built-up edge. To mitigate this problem and to enhance micromachinability of the workpiece in laser-assisted micromilling, this article investigates the following lubrication and cooling methods: (1) minimum quantity lubrication and (2) vortex tube cooling. Experiments utilizing the two methods are carried out on a difficult-to-cut stainless steel (A286), and the surface morphology, tool condition, burr formation, groove dimensional accuracy, surface finish, and cutting forces are analyzed. Results show that the combination of laser-assisted micromilling and minimum quantity lubrication yields the least amount of tool wear, lower resultant force, better groove dimensional accuracy, and no built-up edge. While vortex tube cooling with laser-assisted micromilling produces smaller burrs compared to minimum quantity lubrication, it yields larger changes in groove dimensions and is characterized by built-up edge formation. Possible physical explanations for the experimental observations are given.


Author(s):  
Justin L. Milner ◽  
Jeffrey A. Beers ◽  
John T. Roth

Machining is a popular and versatile manufacturing process that is widely used in today’s industry when producing metallic parts; however, limited tool life can make this an expensive and time consuming fabrication technique. Consequently, methods that decrease the rate of tool wear and, thus, increase tool longevity are a vital component when improving the efficiency of machining processes. To this end, cryogenically treating cutting tools (especially high-speed steel tooling) is becoming more commonplace since research has shown that the treated tooling exhibits significantly higher wear resistance. At this point, however, the effect of cryogenic treatments on ceramic tooling has not been established. Considering this, the research herein presents a feasibility study on the effectiveness of using cryogenic treatments to enhance the wear resistance of WG-300 whisker-reinforced ceramic cutting inserts. To begin, the effect of the cryogenic treatment on the insert’s hardness is examined. Subsequently, tool wear tests are conducted at various cutting speeds. Through this study, it is shown that cryogenically treating the ceramic inserts decreases the rate of tool wear at each of the cutting speeds that were tested. However, the degree of wear resistance introduced by cryogenically treating the inserts proved to be highly dependent on the cutting speed, with slower speeds exhibiting greater improvements. Thus, based on this initial study, the cryogenic treatment of ceramic tooling appears to produce beneficial results, potentially increasing the overall efficiency of machining processes.


Author(s):  
S. Vignesh ◽  
U. Mohammed Iqbal

This paper is concentrated on the exploration of carbonaceous nanocutting fluids with the concept of tri-hybridization with improved lubricative and cooling properties by using multi-walled carbon nanotubes, hexagonal boron nitride , and graphene nanoparticles with neat cold-pressed coconut oil in a fixed volumetric proportion. The rheological properties of the nanofluids were studied to assess their performance in real-time end milling operations using an AA7075 work piece on a CNC lathe machine under a minimum quantity lubrication environment. At the outset, the carbonaceous nanofluids gave good performance when compared to conventional cutting fluids. Furthermore, the surfaces of the tribo-pairs and the chips formed were analyzed using a profilometer and high-end microscopes. The results obtained from the experiments confirm that the tri-hybridized carbonaceous nanolubricant has reduced the cutting force, tool wear, and surface roughness when correlated to monotype nanofluids. The scanning electron microscope images of the surface and tool were studied and it was found that the surface quality was maintained while end milling with tri-hybridized carbonaceous nanofluid. Improvement of ∼17%, 20% and 25% in cutting forces, surface roughness and tool wear was found in tri-hybrid fluid when compared to other fluids. Thus, the present work indicates that the addition of carbon-based nanoparticles with coconut oil has offered better performance and is found to be a credible alternative to existing conventional cutting fluids.


2010 ◽  
Vol 34-35 ◽  
pp. 1816-1821 ◽  
Author(s):  
Yu Su ◽  
Ning He ◽  
Liang Li

Cryogenic minimum quantity lubrication (CMQL) is a kind of green cooling/lubrication technique, which consists of the application of a small amount of lubricant (6-100 ml/h), delivered in a refrigerated compressed gas stream to the cutting zone. This paper experimentally investigates the effect of CMQL on cutting temperature and tool wear in high-speed end milling of titanium alloys. Comparative experiments were conducted under different cooling/lubrication conditions, i.e. dry milling, refrigerated air cutting, and CMQL. The refrigerated gas equipment was manufactured based on composite refrigeration method to provide the refrigerated air. The experimental results show that application of CMQL resulted in drastic reduction in cutting temperature and tool wear especially when machining titanium alloys at a high cutting speed.


2018 ◽  
Vol 7 (2) ◽  
pp. 67-69
Author(s):  
Sandeep Kumar ◽  
Sukhpal Singh Chatha ◽  
Rutash Mittal

In all machining processes, tool wear is a major problem and it leads to tool failure. In metal industries, the use of cutting fluids affects both employee’s health and environmental pollution. But the use of cutting fluids becomes necessary to keep tight tolerances and to maintain the work-piece surface properties without damages. Researchers are trying to reduce the use of coolant lubricant fluids in metal cutting to obtain environmental safety. So, to minimize the use of cutting fluids new cutting techniques are investigated. Minimal quantity of Lubrication (MQL) is a recent technique introduced in machining to obtain less tool wear and environment safety. The minimum quantity lubrication was provided with a spray of mixture of air and vegetable oil at suitable pressure. MQL machining was performed much superior compared to dry and wet machining due to substantial reduction in tool wear and cutting zone temperature and a better surface finish. MQL provides neat and clean environment avoiding health hazards due to smoke, fumes and gases etc. In this study work-piece of SAE 1018 were prepared to investigate their Surface finish under turning with coated tool bits. Wear of nose radius of tool bits were analyzed by SEM which results in less wear in MQL process as compared to flood cooling.


Author(s):  
Vishnu Vardhan Chandrasekaran ◽  
Lewis N. Payton

A large statistically designed orthogonal tube turning experiment measuring the forces, tool wear and surface finish involved in machining of AISI 1020 steel under four different cutting environments. The environments studied were nitrogen and cold compressed air against dry machining. Each data run consisted of one minute cutting time at two different feeds of 0.002″/rev. and 0.004″/rev. at a constant depth of cut of 0.125″ width of cut using High speed steel tool material inserts. Post-mortem analysis was carried out under a Keyance microscope to evaluate the wear on the rake face. The cutting force and the thrust force are collected during the machining process with a dynamometer and the data is further processed using Labview software. The surface finish on the work piece after the cutting process is also evaluated based on the average roughness measurement taken from a contact type profilometer. The advantages of using such gaseous cutting fluids are discussed.


2012 ◽  
Vol 523-524 ◽  
pp. 469-474 ◽  
Author(s):  
Fritz Klocke ◽  
Sascha Gierlings ◽  
Drazen Veselovac

In production of safety critical components in aero engine manufacture, to date broaching is the most efficient process machining fir-tree slots in turbine discs. Machining highly thermal resistant Nickel-based alloys, manufacturers commonly use High Speed Steel (HSS) tools and work at low cutting speeds in order to stay at rather low tool wear rates and avoid part quality defects. The key variable affecting tool wear as well as part quality, as in most machining processes, is the temperature. Excessive temperatures in the cutting zone lead to enhanced tool wear on the one hand, and surface defects such as white layer formation and residual tensile stresses on the other hand. In this article, the temperature development is investigated for typical tool geometries and cutting parameters in broaching. Furthermore, the possibility of a temperature control using intermediate variables such as process forces is discussed, and potentials employing a control are explained.


2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Pierre Faverjon ◽  
Joël Rech ◽  
René Leroy

Due to the increasing emphasis on environmental constraints, industry works on how to limit the massive use of lubricants by using the micro-pulverization of oil in machining processes and, especially, in the machining of aluminum alloys for the automotive industry. The success of a machining operation is dependent on a friction coefficient and weak adhesion with the tool-work material interface. This paper aims at identifying the influence of cutting tool substrates (high speed steel (HSS), carbide, polycrystalline diamond (PCD)) and of minimum quantity lubrication (MQL) on the friction coefficient and on adhesion in tribological conditions corresponding to the ones observed in the cutting of aluminum alloys (sliding velocity: 20-1500 m/min). An open ball-on-cylinder tribometer, especially designed to simulate these tribological conditions through Hertz contact, has been used. It has been shown that HSS and carbide substrates lead to large friction coefficients (0.8–1) and substantial adhesion in dry conditions, whereas PCD substrates would lead to lower average friction coefficient values (0.4–0.5) and very limited adhesion, which proves the necessity of using PCD tools in the dry machining of aluminum. It has also been shown that the application of MQL leads to a large decrease of the friction coefficient (0.1–0.2) and eliminates almost all traces of adhesions on pins for any substrates, which shows that MQL is an interesting compromise between dry machining and flood cooling.


Author(s):  
Vishnu Vardhan Chandrasekaran ◽  
Lewis N. Payton

The current study is a statistically designed experiment to evaluate different cutting environments that can be used in machining aluminum 6061 T6. High speed steel inserts were used along with different levels of uncut chip thickness in a classic orthogonal tube turning experiment. The cutting fluids used in this study are nitrogen and cold compressed “shop” air that are compared to the results obtained from dry machining. The force data (cutting force and the thrust force) were collected using a Kistler force dynamometer and processed using Labview software. The tools are subjected to 1 minute of cutting at two different feed rates of 0.002″/rev. and 0.004″/rev at a constant depth of cut of 0.125″ and at a constant speed. The tool inserts after 1 minute of cutting are studied for tool wear using a Keyance microscope. The surface finish of the work piece surface (average surface roughness) after one minute of cutting is examined under a Dektak 150 contact type surface profilometer. Alternative metal working fluid options are discussed.


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