scholarly journals Analysis of the General Tool Life Function of Cutting Tools by Application of the Catastrophe-Theory

Author(s):  
Zoltán Pálmai ◽  
János Kundrák ◽  
Csaba Felhő

Abstract Production technology planning requires information on tool life T and its relation to cutting speed v. As the Taylor formula often cannot be linearized on an lg-lg scale, a general tool life function has been developed for describing a v-T function with a convex-concave part. Using catastrophe theory, an analogy is established between the general tool life function and the cusp catastrophe, allowing topological mapping of the general v-T function. Results were verified by machinability tests in the turning of C35 and C60 conventional and specially deoxidized C-steels during steelmaking. It was found that in the convex-concave section of this function, 2–3 cutting speeds can be selected for a given tool life, which is advantageous for harmonizing tool changes in multi-operation technology.

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 447 ◽  
Author(s):  
Sergey Grigoriev ◽  
Alexey Vereschaka ◽  
Alexander Metel ◽  
Nikolay Sitnikov ◽  
Filipp Milovich ◽  
...  

This paper deals with the Cr-CrN-(Cr0.35Ti0.40Al0.25)N coating. It has a three-layered architecture with a nano-structured wear-resistant layer. The studies involved the investigation into the microstructure (with the use of SEM and TEM), elemental and phase composition (XRD and SAED patterns), wear process pattern in scratch testing, crystal structure, as well as the microhardness of the coating. Cutting tests of tools with the above coating were carried out in dry turning of steel 1045 at cutting speeds of vc = 200, 250, and 300 m·min−1. The comparison included uncoated tools and tools with the commercial TiN and (Ti,Al)N coatings with the same thickness. The tool with the Cr-CrN-(Cr0.35Ti0.40Al0.25)N coating showed the longest tool life at all the cutting speeds under consideration. Meanwhile, a tool with the coating under study can be recommended for use in turning constructional steel at the cutting speed of vc = 250 m·min−1. At this cutting speed, a tool shows the combination of a rather long tool life and balanced wear process, without any threat of catastrophic wear.


Author(s):  
Samved Bhatnagar ◽  
William J. Endres

Machining of space age materials like Ti-6Al-4V is associated with thermally activated wear mechanisms which lead to rapid tool failure and increased machine downtime. The high strength and low thermal conductivity of Ti-6Al-4V can reduce tool-life significantly at high cutting speeds adding drastically to the per-unit cost. A new concept, Micro Quantity Internal Cooling (MQUIC™) has been developed to extend the tool-life and/or enable higher cutting speeds while machining Ti-6Al-4V. The concept involves introducing flow (coolant) in a micro-duct placed inside the tool and close to the cutting edge, thus bringing the cooling source close to the heat source (chip-contact area). In this research, experiments have been conducted to compare the performance (wear rates) of cutting tools using the MQUIC™ concept with those run under dry or flood conditions. Further, two levels of feed and cutting speed are selected for the experiments so as to be able to investigate the combined effect of parameters on tool performance. Physical testing employing coolant consumption of less than 5% of typical flood coolant rates proves the viability of the concept by demonstrating wear rates of 1/3 to 1/2 those of flood cooling. The testing also proves the application of the MQUIC™ concept to enable higher cutting speeds than the current industry standard for machining Ti-6Al-4V. This paper presents the experimental setup, methodology and results obtained while testing the feasibility of the concept.


2013 ◽  
Vol 581 ◽  
pp. 38-43 ◽  
Author(s):  
Zoltán Pálmay

Cutting tool life is usually described by means of the well-known Taylor formula, which originally specifies tool life as a function of cutting speed. That cutting is performed with the same tool at various successive speeds, thereby rendering the Taylor formula is unusable, which is a common problem. In the case of periodically changing cutting speeds it can be verified both theoretically and through experiments that equation Σ∆ti/Ti≈1 is valid. The generalised form of the Taylor formula, which can also be applied for cutting at periodically changing speeds, could be derived from this equation. If cutting is performed at various speeds, an equivalent speed and a corresponding tool life, which can also be handled by means of the traditional Taylor formula, may be specified.


Author(s):  
Daniel Waldorf ◽  
Scott Liu ◽  
Michael Stender ◽  
Daniel Norgan

This study examines the performance of a new class of wear-resistant but economical cutting tools produced by varying the binder composition of standard cemented carbide composites. By replacing some or all of the cobalt binder with rhenium and nickel-based superalloy, a stronger composite tool results, potentially capable of machining heat-resistant superalloys at significantly higher cutting speeds. Sample tools with alternative binder were produced and compared to standard tools bound with cobalt only. Turning experiments on Inconel 718 were run to evaluate wear resistance and tool life for several grades. The experimentation also examined the effects of varying the relative proportions of each binder constituent as well as the overall binder percentage in the composite. Results show a clear advantage of the alternative binder tools as evidenced by a 150% increase in tool life or the equivalent of an 18% increase in cutting speed. Although increasing amounts of rhenium in the binder show a positive effect on performance, the effects of superalloy and overall binder % are inconclusive.


Author(s):  
Mitsuru Hasegawa ◽  
Tatsuya Sugihara

Abstract In cutting of Ti-6Al-4V alloy, the cutting speed is limited since a high cutting temperature leads to severe tool wear and short tool life, resulting in poor production efficiency. On the other hand, some recent literature has reported that various beneficial effects can be provided by forming micro-textures on the tool surface in the metal cutting process. In this study, in order to achieve high-performance machining of Ti-6Al-4V, we first investigated the mechanism of the tool failure process for a cemented carbide cutting tool in high-speed turning of Ti-6Al-4V. Based on the results, cutting tools with micro textured surfaces were developed under the consideration of a cutting fluid action. A series of experiments showed that the textured rake face successfully decreases the cutting temperature, resulting in a significant suppression of both crater wear and flank wear. In addition, the temperature zone where the texture tool is effective in terms of the tool life in the Ti-6Al-4V cutting was discussed.


2010 ◽  
Vol 33 ◽  
pp. 173-176
Author(s):  
X.Y. Wang ◽  
S.Q. Pang ◽  
Q.X. Yu

The aim of this work is to investigate the machinability of new coated carbide cutting tools that are named C7 plus coatings under turning of superalloy GH2132. This achieved by analysis of tool life at different cutting conditions .Investigations of tool wear and tool life testing are intended to establish T-V formulas, and then analyzed the characteristics of coating . Through a series of comparative tests, Using TiAlN coatings as the contrast materialthe results show that the new coating tools that are named C7 plus coatings are suitable for cutting superalloy GH2132. The cutting speed and processing efficiency can be increased effectively.


2013 ◽  
Vol 581 ◽  
pp. 261-265 ◽  
Author(s):  
Ottó Szabó

Optimisation of technological processes is an important field of research of machining processes. Honing process, its aim and results are affected more factors. Effectiveness is expressed by the following parameters: accuracy, surface roughness, complex surface quality (integrity),material removal rate, costs and productivity of the process. Developed method helps the technology planning and with the introduced new goodness indicator, investigates and corrects it. Optimization and minimization of costs can be ensured at given technological circumstances and technological parameters. With adjustment of the pressure (p) and the cutting speed (vc) economy of the process can be increased in the factory. Developed method can be applied for machining by other abrasive cutting tools. The paper summarizes new results of this theoretical and experimental research.


1981 ◽  
Vol 103 (1) ◽  
pp. 126-130 ◽  
Author(s):  
S. Rossetto ◽  
A. Zompi

A tool-life model based on the assumption that wear and fracture are the causes of tool death is re-examined from the theoretical standpoint, and extended to include the effect of cutting speed on the fracture-induced failure rate. A stochastic model for multi edge cutting tools is also proposed. This enables the overall statistics to be derived from the data for each individual cutting edge.


Author(s):  
Abdullah Altin

In this research, we had studied the sensitivity for machining of cobalt-based superalloy Haynes 188 with ceramic cutting tool. The investigation had focused on the effects of the cutting speed, on the cutting forces, and on the surface roughness based on Taguchi’s experimental design. The effects of machining parameters were determined using Taguchi’s L27 orthogonal array. The signal-to-noise ratio was calculated for the average of surface roughness and the cutting forces, and the smaller were used to determine the optimal cutting conditions. The analysis of variance and the signal-to-noise ratio had effects on the parameters on both surface roughness and cutting. Three different types of cutting tools had been used in the experiment, namely KYON 4300, KYS 25, and KYS 30. The cutting force of Fz was considered to be the main cutting force. Depending on the material which had been used as cutting tool, the Fz had the lowest cutting speed and the lowest surface roughness with the KYS25 ceramic tool. The cutting force and the surface roughness of KYON 4300 cutting tool had shown better performance than other cutting tools. The flank wear and notch were found to be more effective in the experiments. The long chips were removed at low and medium cutting speeds, while the sawdust with one edge and narrow pitch at high cutting speeds was obtained.


Author(s):  
Rosemar Batista da Silva ◽  
Álisson Rocha Machado ◽  
Déborah de Oliveira Almeida ◽  
Emmanuel O. Ezugwu

The study of cutting fluid performance in turning is of great importance because its optimization characteristics has associated benefits such as improved tool life and overall quality of machined components as well as reduction in power consumption during machining. However, there are recent concerns with the use of cutting fluids from the environmental and health standpoints. Since environmental legislation has become more rigorous, the option for “green machining” attracts the interest of several manufacturing companies. It is important to consider the cost of machining which is associated with tool wear, depending on the cutting environment. The use of vegetable oil may be an interesting alternative to minimize the health and environmental problems associated with cutting fluids without compromising machining performance. This paper presents a comparative study of mineral and vegetable cutting fluids in terms of tool wear after turning SAE 1050 steel grade with cemented carbide cutting tools. Constant depth of cut of 2mm and variable cutting speed (200 and 350 m/min) and feed rate (0.20 and 0.32 mm/rev) were employed. Test results suggest that is possible to achieve improvement in machinability of the material and increase tool life by using vegetable cutting fluid during machining. Tool life increased by about 85% when machining with vegetable-based fluids compared to mineral-based fluids. Analysis of the worn tools, however, revealed a more uniform wear on the worn flank face when machining with mineral-based fluids.


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