Increase Tool Life Research Articles

Increased Operating Properties of Cutting Ceramics by Application of Nanostructured Multilayer Wear-Resistant Coating

This paper presents the results of the development of nanoscale multi-layered composite coatings for improving the contact performance of ceramic cutting tools. These nanocoatings help reducing brittle fracture of cutting edges and ensure a balanced wear of tool contact areas during dry high-speed machining of hardened steels. A filtered cathodic vacuum arc deposition process was used to generate the nanoscale multi-layered composite coatings (NMCC) with improved physical and mechanical properties and adhesion strength to ceramic substrate. In this work, thermodynamic criteria were used to evaluate the selected composition of NMCC, and the crystal-chemical, physical, mechanical and cutting properties and wear mechanisms were studied. Ti-(TiAl)N-(ZrNbTiAl)N coating was deposited on Al2O3, Al2O3-TiC and Si3N4 ceramic substrates. Test results showed that the wear mechanism of the coated tool was predominantly due to adhesive-fatigue processes. The development of wear was observed to be centered on the rake and flank faces of the tool without brittle chipping. The results of high-speed longitudinal turning of hardened steel X153CrMoV12 showed an increase in tool life by a factor of 1.5 against the uncoated tools and a factor of 1.3 compared with standard PVD coating Ti-(TiAl)N.

Modification of surface morphology to enhance tribological properties for CVD coated cutting tools through wet micro-blasting post-process

Coated cemented carbide tools have been widely applied in high performance machining due to their excellent heat resistance and anti-wear properties. However, as-deposited tool coatings are still challenged by the growing requirements to further enhance cutting performance. Wet micro-blasting post-process on coating tools has been proposed to improve mechanical properties and increase tool life. This paper aims to optimize the wet micro-blasting operating parameters for chemical vapor deposition (CVD) coated tools to strengthen their wear resistance. The surface morphology of three types of CVD coated tools including TiN/Al2O3/TiCN, thin Al2O3/TiCN and thick Al2O3/TiCN are inspected with EDS, SEM and AFM. Tribological properties for both as-deposited and wet micro-blasted tool coatings were evaluated by dry reciprocating sliding tests. The measured results indicate that the wet micro-blasting process can significantly decrease the surface roughness and improve the wear resistance. Among the wet micro-blasting operating parameters, the wet micro-blasting time and the abrasive particle size are found to play more important roles in the formatting of top surface morphology and the enhancement of the tribological behavior than the role played by blasting pressure. Based on the research results, the CVD tool coatings with improved anti-wear properties and surface topography can be fabricated with suitable wet micro-blasting process parameters.

A study of energy consumption in turning process using lubrication of nanoparticles enhanced coconut oil (NECO)

Cutting fluids play very important role in machining application in order to increase tool life, surface finish and reduce energy consumption. Instead of using petrochemical and synthetic based cutting fluids, vegetable oil based lubricants is safety for operators, environmental friendly and become more popular in the industrial applications. This research paper aims to find the advantage of using vegetable oils (coconut oil) with additional of nano particles (CuO) as lubricant to the energy consumption during machining process. The energy was measured for each run from 2 level factorial experimental layout. Obtained results illustrate that lubricant with enhancement of nanoparticles has capability to improve the energy consumption during the machining process.

Eco-friendly technology for recycling of cutting fluids and metal chips: A review

Recently, as environment regulations have been strengthened around the world, new policies that take the environment into consideration have been introduced in various industries. As a result, to protect against environmental pollution and save resources, eco-friendly technologies have been studied. Especially in the machining and machinery industries, interest in how to handle the recycling of cutting fluids and metal chips has increased because these materials are highly toxic. Cutting fluids increase tool life and productivity by cooling and lubricating during processing. However, cutting fluids and metal chips result in environmental pollution and are harmful to the human body. In order to solve the problems associated with these materials, eco-friendly technologies for the recycling of cutting fluids and metal chips have been proposed by researchers and industrial workers. In this paper, a review of physical, chemical and biological recycling methods for cutting fluids is performed, and research and development in relation to the recycling of metal chips are reviewed. Moreover, companies involved in the recycling metal chips are summarized based on the country of origin. The final part of this paper provides a technical summary of cutting fluids and metal chips according to associated the methods used to recycle these materials.

Hole machining based on using an incisive built-up reamer

This article deals with analyzing the existing cutting tools and ways of hole-making operations. The newly designed tool consists of four false teeth-incisors and the curved cutting edge. This tool provides the possibility to increase the hole quality (tolerance of size, surface roughness), to facilitate cutting and to increase tool life. Experimental studies related to hole processing were carried out by using a scanner. Reproducibility of the experiment was determined according to Cochran's criterion G. The obtained results were processed through the mathematical apparatus of the full factorial experiment of type 23. Based on relevant data measurements, the authors of this research built graphics based on the accuracy of diametric dimensions of the processed holes, spindle rotation frequency and cut feed, as well as on the dependence of surface roughness from technological factors (workpiece speed, feed and length). The graph shows that deviation of the diametric size increases with increase in feed and decreases with the speed increase; surface roughness is inversely proportional to workpiece speed. Precision machining of holes corresponds to 5-6 accuracy degree, which is higher by one or two orders of magnitude compared to using standard hole boring cutters and scans.

Evaluation of friction and wear characteristics of electrostatic solid lubricant at different sliding conditions

In modern industry, mechanical parts are subjected to friction and wear, leading to heat generation, which affects the reliability, life, and power consumption of machinery. Effective cooling and lubrication in the machining zone are essential to improve friction and temperatures by efficient heat dissipation which increases tool life and surface quality. Solid lubricant additives have demonstrated better tribological performance in terms of reducing friction and sliding zone temperature without polluting the environment. With an appropriate application of solid lubricant additives in the sliding interface, the friction reduction and wear resistance properties of the lubricant have been successfully improved. Therefore, an attempt has been made in this research work with an investigation of using molybdenum disulphide suspension to reduce the friction at machining zone. To achieve this, in the present work, novel electrostatic charged solid lubricant spray technique (ECSL) has been envisaged for effective supply of solid lubricant mixture at an extreme low flow rate to the sliding interface of WC pin and Ti–6Al–4V alloy as disc materials. Excessive tribological measurements with SAE 40 oil concentrated with 20wt% of MoS2 with micron size particles results in lower friction coefficient and wear because of the fact that particles with small size were more likely to interact with the sliding surfaces of the friction pairs to form a surface protection film, which increases anti-wear ability of sliding surface. The results indicate that the solid lubricants applied effectively with the developed experimental set-up and improve the tribological properties of the sliding surface.

Performance study of multilayer carbide tool in high-speed turning of API 5L X70 pipeline steel using a cold air system

Turning is the most widespread manufacturing process in the industry due to its high flexibility in machining for simple and complex parts. The study of surface roughness and tool wear are the main responses in the machining processes, mainly in the turning process. The great challenge in the modern industry is to increase the productivity with time reduction without decreasing the quality and raising the costs of the products. In this study, seamless tubular workpieces of API 5L X70 steel were used to define the surface roughness and the tool wear. The responses were tool life with VBmax greater than or equal to 0.3 mm and lowest surface roughness value in machining tests using a dry and cold air system. The results demonstrated that the use of high cutting speeds provided a significant reduction in tool life. The use of the cold air system provided a good increase in tool life for the traditional speed. On the other hand, the turning process with the cold air system and high-speed cutting reduced the tool life significantly. Finally, the increase in VBmax provided the increase in surface roughness of the workpieces. Concerning the cutting speed, it was found that their increase provided a reduction in the cutting efforts, both in dry experiments and in experiments with the cold air system.

Sustainability analysis of lubricant oils for minimum quantity lubrication based on their tribo-rheological performance

Nowadays, environmentally friendly cutting fluids should be applied in manufacturing processes. Concretely, in many machining processes the use of minimum quantity of lubrication (MQL) is established as common routine. In this paper, the use of natural biodegradable oils as an alternative to traditional canola oils used in MQL is analyzed, comparing five different alternatives (i.e.: sunflower oil, high oleic sunflower oil, castor oil and ECO-350 recycled oil). Firstly, the aim is to evaluate the feasibility of the proposed oils, just analyzing their tribological and rheological characteristics. Secondly, a full battery of experimental tests was performed in order to validate their behavior during cutting Inconel 718, a difficult-to-cut material commonly used in aeronautical components. Finally, life cycle assessment was carried out with the aim of analyzing their environmental feasibility. Results show that the combination of low viscosity with high friction coefficient implies an increase in tool life. In this line, ECO-350 recycled oil presents a feasible behavior and improves the tool life up to 30% in comparison with commercial canola oil. However, its recycling process has to be improved from an environmental point of view. Taking both issues, high oleic sunflower oil presents a balance between them. On one hand, it improves tool life (15%) and on the other hand, similar environmental impact is obtained compared with canola oil. This supposes an advance, being more efficiently, not only environmentally speaking but also technically.

Experimental-numerical analysis of contact conditions influence on the ironing strip drawing process

PurposeThe purpose of this paper is comparison of experimental values of the drawing forces to numerical values in different contact conditions, taking into account the appearance of galling which occurs due to of difficult drawing process conditions.Design/methodology/approachThe following two research approaches are used in this paper – the physical modeling, realized by the laboratory experiment, and the numerical simulation of the ironing drawing process. By analyzing the obtained results, the technique of physical modeling, with help of the laboratory equipment and numerical simulation by application of the finite element method, can be successfully used in studying the thin sheet ironing – strip drawing process.FindingsIt is significant to compare values of the deformation forces obtained by physical experiment to values obtained by the numerical simulation. In that way, it is possible to compare applied contact conditions (four lubricants in that case) and estimate matching of experimentally and numerically obtained results of the deformation forces. Presented results point out very good technological characteristics of ecologically friendly lubricant (single-bath) and grease based on MoS2. Significant decrease of the deformation force was achieved by its application, as well as maintaining of the lubricant’s layer during the forming process and almost complete elimination of galling on the contact.Practical implicationsNumerical analysis of stresses in the working piece wall, during the thin sheet strip drawing, requires precise values of the friction coefficient. It is an important indicator because one can define the contact conditions as the input data for the numerical simulation, based on its values for each type of lubricants and each value of the compressive lateral force.Originality/valueThe environmentally friendly lubricant tested exhibits a more favorable distribution of the drawing force during the process, mainly in experimental case. Grease based on MoS2 has good lubricating properties but that lubricant is conventional and environmentally unacceptable. Ecologically friendly lubricant can be successfully used in real ironing strip drawing process especially for high values of holding force achieving an increased tool life.

Impact of supply conditions of liquid nitrogen on tool wear and surface integrity when machining the Ti-6Al-4V titanium alloy

Cryogenic-assisted machining has already shown its advantages on the process and the machining parameters have been analysed. However, part of the coolant jet characteristics as the pressure and flow rate have not been completely studied and optimized. Hence, the main objective of this study is to investigate the impact of these parameters on tool wear and surface integrity when machining the titanium alloy Ti-6Al-4V. Several nozzle diameters have been therefore employed in order to vary the pressure and the flow rate. A new nozzle holder has been developed to ensure the replacement of these calibrated nozzles of different diameters. The machining tests have allowed to draw attention to the impact of the pressure and the flow rate of the liquid nitrogen jet not only on tool life but also on surface integrity. Indeed, the increase of flow rate and pressure increases tool life. Moreover, surface integrity has been greatly improved notably at the highest pressure and the highest flow rate.

Influence of surface preparation on the tool life of cathodic arc PVD coated twist drills

Cutting tool micro-geometry and surface integrity have been critical aspects to be considered for successful application of PVD thin films for cutting tool life enhancement. The present study examines in detail the role of pre-coating surface preparation (micro-blasting and drag finishing) on the tool life of coated cutting tools. TiN coating was deposited on different kinds of pre-treated (Micro blasting, Edge rounding and a combination of both) HSS and WC drills using cylindrical cathodic arc deposition method. They were subsequently characterized for surface roughness (Ra), adhesion strength and machining performance on EN 24 material. Pre-coating surface roughness (developed due to pretreatment) has a major influence on the adhesion strength of the coating. A lower pre-coating surface roughness with optimized edge rounding led to higher adhesion and edge strength which in turn resulted in a notable increase in tool life. Further underlining the importance of the present study, commercial TiN coatings deposited on HSS substrates were tested. The tool life obtained in the current study prolonged the tool life by a factor of 3 in comparison to the commercially available tools in the present day market.

Electrostatic high-velocity solid lubricant machining system for performance improvement of turning Ti–6Al–4V alloy

In any machining operation, a major division of energy is converted into heat which creates detrimental effects on tool wear, tool life and surface quality of machined work material. Effective cooling/lubrication in the machining zone is essential to improve friction and temperatures by efficient heat dissipation which increases tool life and surface quality. But adverse health effects caused by use of flood cooling are drawing manufacturers’ attention to develop methods for controlling occupational exposure to cutting fluids. In demanding the improvement of productivity and product quality of machining, use of solid lubricant thin film was suggested as one of the necessary alternative machining techniques to apply lubricants effectively to the high-temperature zone. There is a general concern in the machining process in terms of applying lubricants effectively to the machining zone. Therefore, this research work contributes to the development of a novel approach to apply lubricants effectively to the rake face and flank face of the cutting tool without polluting the environment. Electrostatic high-velocity solid lubricant assisted machining is a novel technique used in the machining process with a very low flow rate (1–20 mL/h) to enhance the process performance of turning difficult-to-cut materials. The performance of electrostatic high-velocity solid lubricant technique is studied in comparison to minimum quantity solid lubricant, minimum quantity lubricant and dry and wet (flood cooling) to assess the performance considering surface roughness, cutting force and tool wear as performance indices. The experimental results revealed that electrostatic high-velocity solid lubricant with MoS2 solid lubricant at low volume and constant flow rate has observed high potential to apply lubricants effectively in the machining zone when compared with the considered environmental conditions. This work is expected to form a scientific basis toward developing electrostatic high-velocity solid lubricant technique for reducing the manufacturing impact in the machining of aerospace components such as Ti–6Al–4V alloy in terms of both machinability and environmental perspectives.

Influencia del sistema de mínima cantidad de lubricante (MQL) en la vida de las herramientas de corte de metal duro en el fresado del acero AISI 1018


 
 
 Hoy en día, la alta productividad del mecanizado es un tema importante para obtener beneficios económicos en la industria. Este propósito podría alcanzarse con mayores velocidades de corte y avance. Sin embargo, el comportamiento inherente produce altas temperaturas en la interfaz de la herramienta de corte / pieza de trabajo. Muchos fluidos de corte han sido desarrollados para controlar la temperatura en el proceso y aumentar la vida de la herramienta. El objetivo de este trabajo es comparar el desgaste de la herramienta de fresado de insertos de metal duro con diferentes sistemas lubricantes/refrigerantes: Sistema Tradicional por Inundación y el Sistema de Mínima Cantidad de Lubricante (MQL). Los valores de desgaste de las herramientas de corte se evaluaron de acuerdo con la norma ISO 8688-1 1989. Los resultados experimentales mostraron que el uso del MQL reduce significativamente el desgaste de la herramienta (aproximadamente 40%) en el fresado de acero AISI 1018 en condiciones industriales de corte. 
 
 

The influence of tool-surface contact on tool life and surface roughness when milling free-form geometries in hardened steel

Machining process planning for milling hard materials with free-form surfaces using a ball nose end mill still requires empirical determination of the machining parameters, which can limit the efficiency of the process, reduce tool life, and adversely affect workpiece surface quality. Milling free-form surfaces differs from ordinary milling because the tool-surface contact changes constantly, causing the cutting speed to vary from the programmed value (in regions where the tool touches the surface with its nominal diameter and the tool axis is parallel to the surface) to zero (in regions where the center of the tool tip cuts the material and the tool axis is almost perpendicular to the surface at the point of contact). This paper focuses on this issue and investigates the influence of effective cutting speed and tool-surface contact on tool wear and surface roughness. High-speed milling experiments were carried out in which convex circular surfaces of hardened D6 steel were machined with a ball nose end mill keeping the effective tool diameter along the tool’s circular trajectory constant in each experiment. The input variables were the lead angle (and consequently the effective tool diameter, which was kept constant in each experiment but varied from one experiment to another) and feed direction (ascendant and descendant). As the effective tool diameter increased from one experiment to another, the feed rate decreased. The results show, in contrast to other findings in the literature, that contact between the center of the tool tip and the workpiece can increase tool life and reduce roughness when milling free-form surfaces in hardened steels. Furthermore, machining time is reduced as the smaller effective tool diameter leads to a higher feed rate. A relationship was also observed between the axial machining force and process stability when the tool tip is involved in the cutting process.

Increasing productivity in turning of hard-to-cut materials by means of modified flank faces

The high thermo-mechanical tool load during cutting of hard-to-cut material leads to an increased tool wear, which affects the surface integrity and tool life adversely. An innovative approach to counter the wear is to retract the tools flank face at a certain distance from the cutting edge. The so-called flank face modification geometrically limits the tool wear and increases the available material of the tool, which can be removed by the abrasive cutting process until a certain tool life criterion is reached. However, the flank face modification weakens the mechanical stability of the cutting edge. To avoid tool breakage due to excessive mechanical stress, this paper presents a new design approach based on static finite element simulations. Finally, experimental results show an increase in tool life up to 75% compared to conventional tools with these designed modifications

Effecton Surface Properties OF Mild Steel During Dry Turning & Wet Turning On Lathe

In order to tackle a multi-objective optimization problemwhich seeks identification of the best process condition or parametric combination for the manufacturing processes, dry and wet turning, In the present experiment investigation on straight turning of mild- steel bar by using HSS tool. The experiment aimed at evaluating the best process environment which could simultaneously satisfy requirements of both quality and as well as productivity with special emphasis on reduction of cutting tool flank wear. Because reduction in flank wear ensures increase in tool life. The predicted optimal setting ensured minimization of surface roughness, height of flank wear of the cutting tool and maximization of MRR (Material Removal Rate).The experimental analysis showed that surface properties of mild steel improved when wet turning was carried out instead of dry turning.

Tool Life Analysis when Turning Ti-6Al-4V Using Vegetable Oil-Based Cutting Fluid

This paper details experimental results when turning Ti-6Al-4V using water-miscible vegetable oil-based cutting fluid. The effects of coolant concentration and working conditions on tool flank wear and tool life were evaluated. L27 fractional factorial Taguchi array was employed. Tool wear (VBB) ranged between 28.8 and 110 µm. The study concluded that a combination of VOs based cutting fluid concentration (10%), low cutting speed (58 m/min), feed rate (0.1mm/rev) and depth of cut (0.75mm) is necessary to minimise VBB. Additionally, it is noted that tool wear was significantly affected by cutting speeds. ANOVA results showed that the cutting fluid concentration is statistically insignificant on tool flank wear. A notable increase in tool life (TL) was recorded when a lower cutting speed was used.

Comparison of Wear Properties of AISI D3 and O1 Steel with the Same Hardness

Die wear is an undesired and unpredictable failure and downtime reason in metal forming operations. It directly affects the part formability and surface quality, and causes production loss, cost increase and delays. In sheet metal stamping, the wear of deforming dies continues to be a great concern to the automotive industry as a result of increasing die maintenance cost and scrap rate. The demand to reduce the use of lubricants and increase tool life in sheet metal stamping has resulted in increased research on the suitable combination of die materials. During production, the higher forming forces, higher wear; galling and premature die surface failures, and eventually insufficient product quality, interrupted production, and unexpected cost increases. Hence, in order to prolong the die-life, reduce down-time, and increase production rate and profitability; manufacturers are looking into alternative die materials, coatings, lubricants and their compatible combinations that would increase the die-life/ performance at reasonable cost levels. There are so many options and combinations of die materials and coatings that it is rather time-consuming to select a proper, if not optimal, pair of die material and coating for a given application. The various types of tool or die steels are there which are used in industries like sheet metal industry and press working. The wear of tools or dies is a common problem in these industries. Hence the present study aims to investigate the wear performance of AISI D3 die steel against mild steel under dry sliding conditions. Sliding parameters such as sliding speed, sliding time and normal load are taken.

Substitution of Coolant by Using a Closed Internally Cooled Milling Tool

The saving of raw materials plays a major role in industry and is becoming increasingly important. In the field of cutting technology, the aim is to maximise practices such as the substitution of coolant and the steady increase of tool life in order to make an effective contribution towards environmental protection. Concerning the saving of coolant and to enhance the performance in dry machining a milling tool with a closed internally cooled system was developed. Heatpipes are applied which ensure improved heat dissipation from the cutting edge because of their excellent thermal conductivity. The dissipated heat is subsequently delivered to the surroundings via a heat sink. This contribution describes how the performance of a standard tool can be enhanced by the integration of a closed internally cooled system. Simulations of the heat distribution in the tool have been conducted to design and optimise the prototype. Hence, milling tests on duplex steel and temperature measurements in the cutting process have been carried out to verify and further optimise these simulation results.

CFD Simulation and Optimize of LN2 Flow Inside Channels Used for Cryogenic Machining: Application to Milling of Titanium Alloy Ti-6Al-4V

Cryogenic machining is seen as a possible solution to increase tool life and improve surface integrity of machined components, by efficiently removing the heat from the cutting zone. Unfortunately, most of the publications on this topic does not investigate properly the physical phenomena occurring inside the pipe connecting the tank to the cutting tools/nozzle. These phenomena will affect the cryogenic flow characteristics at nozzle outlet, thus the performance of the cryogenic machining.In this work, a CFD model is developed and applied to investigate the liquid nitrogen (LN2) flow inside the pipe connecting the reservoir to the cutting tool/nozzle. The results show that the effectiveness of the cooling process depends not only on the input flow parameters (pressure, velocity, temperature and gas/liquid fraction), but also on the pipe geometry.