Possibilities of Application of High Pressure Jet Assisted Machining in Hard Turning with Carbide Tools (original) (raw)
Related papers
Journal of Mechanical Engineering, 2015
Hard turning of harder material differs from conventional turning because of its larger specific cutting forces requirements. The beneficial effects of hard turning can be offset by excessive temperature generation which causes rapid tool wear or premature tool failure if the brittle cutting tools required for hard turning are not used properly. Under these considerations, the concept of high-pressure coolant (HPC) presents itself as a possible solution for high speed machining in achieving slow tool wear while maintaining cutting forces at reasonable levels, if the high pressure cooling parameters can be strategically tuned. This paper deals with an experimental investigation of some aspects of the turning process applied on hardened steel (HRC48) using coated carbide tool under high-pressure coolant, comparing it with dry cut. The results indicate that the use of high-pressure coolant leads to reduced surface roughness, delayed tool flank wear, and lower cutting temperature, while also having a minimal effect on the cutting forces.
New trends in cutting technologies: application of high pressure jet assisted machining
High Pressure Jet Assisted Machining (HPJAM) in turning is a hybrid machining method in which a high pressure jet of cooling and lubrication fluid is directed to the contact zone between chip and cutting tool. It uses in highly productive processes of chip removal - roughing and semi-machining. This paper shows that the application of HPJAM offers great advantages in regarding of materials machinability. Workpiece material used in experimental research in turning process was the construction carbon steel C45E with hardness of 45 HRc and alloyed bearings steel with high resistance to wear 100Cr6 and hardness of 62 HRc. Experimental researches are performed, and material machinability in metal cutting is analyzed.
Hard turning of bearing steel AISI 52100 with carbide tool and high pressure coolant supply
Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2017
The improvement of productivity, efficiency, and product quality requires the use of modern machining equipment, and modern process management. Successful management of the cutting processes requires a lot of knowledge about workpiece materials, cutting tool materials and geometry, tool machine, cooling and lubrication fluids including dosage techniques, and cutting conditions. However, the mentioned requirements are difficult to achieve in hard turning (Fig. 1). Hard turning is the cutting process for workpiece materials which are hardened above 45 HRc. This method has been introduced to replace traditional processes, which included turning, heat treatment and grinding [1]. Hard turning is almost performed using harder cutting tool materials such are the ceramics (Al 2 O 3) and cubic boron nitride tools (CBN), at lower cutting parameter values. The use of these tools and parameters causes expensive production, because of expensive tools and long machining time. The use of brittle tools requires continuous cut due to poor toughness of cutting tool edges. Use of cooling and lubrication fluid supplied under high pressure can bring some improvements in machining. This technique of fluid supplying dates from the fifties of the last century. In modern machining are used the high pressure tool systems that allow the fluid supply under pressures up to 15 MPa. The high pressure jet assisted machining (HPJAM) concept is to inject an extremely high pressure jet of cooling and lubrication fluid in the cutting zone, between chip and tool edge. In this techniques are used pressures from 40 to 200 MPa, so that jet is participating in the chips forming, similar to the non-conventional technologies [2-4]. HPJAM was established as a method that would substantially increase the removal rate and Abstract The machining of hard-to-machine bearing steel AISI 52100 (100Cr6), hardened to 62 HRc, is almost impossible using standard machining conditions and carbide cutting tools. The purpose of this research is machinability analysis and conclusions about the conditions that allow the machining of mentioned steel with carbide tools. In this paper, the turning process is carried out using coated carbide inserts and high pressure jet assisted machining, as a special technique of cooling and lubrication. In this technique, coolant circulation system with filters, environmentally acceptable, is used. A jet of cooling and lubrication fluid under extremely high pressure (50 MPa) is directed into the zone between the cutting tool edge and the workpiece. Experimental measurements were performed for different cutting parameters. Cutting forces, tool wear, surface roughness, chip shapes, and material removal rates were analyzed. The presented results show an increase in productivity, low intensity tool wear, and surface roughness in acceptable limits.
Journal of Mechanical Engineering, 2009
To avoid surface distortion and to improve tool life, machining of alloy steel and other hard materials under high speed-feed condition requires instant heat transfer from the work-tool interface where the intensity of cutting temperature is the maximum. Conventional cooling is completely unable and other special techniques like MQL and cryogenic cooling are not suitable in context of product quality and cost effectiveness. Supply of high-pressure coolant (HPC) with high velocity may provide the best control to reduce cutting temperature and tool wear as well as increase tool life. This paper deals with an experimental investigation on the effect of high-pressure coolant on temperature, tool wear, surface roughness and dimensional deviation in turning 42CrMo4 steel by uncoated carbide inserts and comparing it with dry condition. It is observed that the cutting temperature and tool wear is reduced, tool life is increased, surface finish is improved, and dimensional deviation is decre...
Role of High-Pressure Jet Cooling on Cutting Temperature in Turning Steel
The present work deals with development of mathematical model of temperature distribution in chip-tool-work piece interface in turning of medium carbon steel under high-pressure coolant (HPC) condition and subsequently verify it with experimental investigation. Continuous or steady state machining operations like orthogonal cutting are studied by modeling the heat transfer between the tool and chip at the tool rake face contact zone. The shear energy created in the primary zone, the friction energy produced at the rake face-chip contact zone and the heat balance between the moving chip and stationary tool are considered. To determine the temperature distribution in metal cutting is very laborious and time intense through experiment. By using FEM, the temperature distribution in chip-tool-work piece interface can be achieved very accurately. The mathematical model for cutting temperature has been developed and MSC Nastran / Patran simulation software was used to illustrate the temperature distribution. The results were then verified with the experimental data for dry machining. As the results satisfy with acceptable margin, the model then applied for high-pressure coolant condition to find out the temperature distribution in chip-tool-work piece interface. The mathematical models and simulation results are in satisfactory agreement with experimental temperature measurements reported in the literature. In high-pressure coolant condition the average cutting temperature reduced by 16% than dry condition. The model provides reasonably acceptable results in terms of deviation from actual result, with 5% deviation for temperature model. Thus the model proves its validity. As the temperature at the chip-tool interface is one of the two most important factor influencing the machining process, so high-pressure coolant condition is complimentary for machining process.
Gazi University Journal of Science, 2010
Metal cutting fluids changes the performance of machining operations because of their lubrication, cooling, and chip flushing functions. The use of cutting fluid generally causes economy of tools and it becomes easier to keep tight tolerances and to maintain workpiece surface properties without damages. However, the conventional types and methods of application of cutting fluid have been found to become less effective with the increase in cutting speed and feed when the cutting fluid cannot properly enter the chip-tool interface to cool and lubricate due to bulk plastic contact of the chip with the tool rake surface. Besides that, often in high production machining the cutting fluid may cause premature failure of the cutting tool by fracturing due to close curling of the chips and thermal shocks. Because of them some alternatives has been sought to minimize these problems. Some of these alternatives are cryogenic machining, minimum quantity lubricant machining and machining with high-pressure coolant jet. This paper deals with experimental investigation on the role of high-pressure coolant on cutting temperature, chips, cutting forces, tool wear, tool life and surface finish in turning of AISI 1060 steel at industrial speed-feed combinations by uncoated carbide inserts. The encouraging results include significant reduction in cutting forces, tool wear, surface roughness and significant improvement in tool life by high-pressure coolant jet mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.
International Journal of Advanced Manufacturing Technology, 2010
High-pressure coolant (HPC) delivery is an emerging technology that delivers a high-pressure fluid to the tool and workpiece in machining processes. High fluid pressure allows for better penetration of the fluid into the cutting zone, enhancing the cooling effect, and decreasing tool wear through lubrication of the contact areas. The main objective of this work is to understand how tool wear mechanisms are influenced by fluid pressure under different cutting speeds in the finish turning of AISI 1045 steel using coated carbide tools. The main finding was that the use of a lower cutting speed (v c = 490 m/min) in dry cutting resulted in tool life close to that obtained with cutting fluid, but when the cutting speed was increased (v c = 570 m/min), the high-pressure coolant was effective in prolonging the life of the cutting tool. It was also concluded that, regardless of the cutting speed and cooling/lubrication system, the wear mechanisms were the same, namely abrasion and attrition.
Dry machining has been successfully used in several machining applications with different cutting tools and workpiece materials due to its environmental friendliness. Dry hard turning has become an alternative machining process to grinding due to its ability to increase material removal rate, reduce production costs, and enhance of material properties. However, hard turning has several issues such as high temperatures at the tool-chip and tool-workpiece interfaces which are affecting negatively on the surface integrity of the machined parts. Using conventional cutting fluids can improve machining performance by reducing the temperature in the cutting area. However, conventional cutting fluids have some issues such as pollution, hazard on operator, high cost, and corrosion for machine tool and workpiece. All these issues related to applications of conventional cutting fluids have encouraged the researchers to look up for another alternative cooling technique in machining operation. Cooling gas has been explored as one of the alternative cooling techniques. The present paper studies the effect of applying nitrogen gas on surface roughness and tool life under different cutting parameters (cutting speed of 100, 135, and 170 m/min, feed of 0.16, 0.2, and 0.24 mm/rev, with constant depth of cut of 0.2 mm) for hard turning of stainless steel (hardness of 48 HRC) using coated carbide tools. Results showed that better surface finish and longer tool life were achieved by using nitrogen gas coolant condition compared to dry cutting.
The growing demand for high productivity machining and grinding particularly high strength and heat resistance materials need use of high cutting velocity and feed. Such machining and grinding inherently generate very large amount of heat and high cutting temperature, which not only reduces tool life but also impairs the product quality. Conventional cooling methods are not only ineffective but also deteriorate the working environment by producing harmful gasses and smokes. Attempts have already been initiated to control the pollution problem by cryogenic cooling which also helps rid of recycling and disposal of conventional fluids and possible damage of the machine parts by corrosion etc. Industries are reasonably interested to know how, apart from environment friendless, high-pressure coolant affects machinability of any material, which have significant role on efficiency and overall economy of manufacturing by machining. The present work deals with experimental investigation in the role of high-pressure coolant on visible product quality and tool wear in plain turning of 16MnCr5 steel rod at different cutting velocities and feeds by uncoated carbide (SNMG) insert. The encouraging results include significant reduction in dimensional inaccuracy, surface roughness and tool wear rate by high-pressure coolant mainly through reduction in the cutting zone temperature and favorable change in the chip-tool interaction.
Anadolu Üniversitesi Bilim Ve Teknoloji Dergisi - B Teorik Bilimler
The application of environment friendly cutting fluid in machining processes can strongly influence the wear on the cutting tools and the surface finish on work piece materials. This is only possible, when the cutting fluid provides better penetration into the cutting zone, thereby providing a better cooling and lubricating effect. Therefore, this study aims to show the effect of various cutting fluid cooling conditions and machining parameters on tool flank wear (VB) and surface roughness (Ra) of work piece while turning AISI D2 steel with coated CBN tools. Response surface methodology (RSM) and analysis of variance (ANOVA) were used to check the validity of quadratic regression model and to determine the significant parameters affecting the desired responses. The results showed that machining time was the most dominant parameter influencing both tool wear and surface roughness. Moreover, cutting fluid conditions also showed considerable contribution towards decreasing tool wear rate and increasing surface finish. In addition, the cutting tools were examined under scanning electron microscope (SEM) together with EDS. It was observed that abrasion along with BUE formation were the most dominant wear mechanism modes at low cutting speeds. However, at higher cutting speed and feed combinations, abrasions followed by diffusion and adhesion were the dominant form of wear mechanisms. Suppression of BUE was observed at higher cutting speeds of CBN tools. Finally, desirability function approach (DFA) was used to find out the optimal cutting parameters for minimum tool wear with maximum surface finish.