The Effect of Speed and Feed on the Mechanics of Metal Cutting

Author(s):  
B. T. Chao ◽  
G. H. Bisacre

When the cutting speed or feed of a metal cutting tool is increased, the most striking effect is on the rate of tool wear, but there are other changes which take place at the same time. These are changes in the geometry of the chip, tool forces, and tool build-up and surface finish. An attempt is made in this paper to form a logical theory to explain these variations in the mechanics of the process. The problem of tool wear is not attempted. A series of tests has been conducted on mild steel and copper, over a wide range of speed, feed, and tool angle; and a theory has been developed. The results arrived at are:— (1) That local temperature in the chip plays an important part in affecting the friction at the chip tool interface. (2) For many purposes effects due to speed and feed can be treated as functions of the product of speed and feed. (3) Temperature does not affect the shear strength of the metal directly. (4) The extent of built-up edge prevailing can be put as a function of the product of speed and feed.

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Harun Gokce

Stainless steels with unique corrosion resistance are used in applications with a wide range of fields, especially in the medical, food, and chemical sectors, to maritime and nuclear power plants. The low heat conduction coefficient and the high mechanical properties make the workability of stainless steel materials difficult and cause these materials to be in the class of hard-to-process materials. In this study, suitable cutting tools and cutting parameters were determined by the Taguchi method taking surface roughness and cutting tool wear into milling of Custom 450 martensitic stainless steel. Four different carbide cutting tools, with 40, 80, 120, and 160 m/min cutting speeds and 0.05, 0.1, 0.15, and 0.2 mm/rev feed rates, were selected as cutting parameters for the experiments. Surface roughness values and cutting tool wear amount were determined as a result of the empirical studies. ANOVA was performed to determine the significance levels of the cutting parameters on the measured values. According to ANOVA, while the most effective cutting parameter on surface roughness was the feed rate (% 50.38), the cutting speed (% 81.15) for tool wear was calculated.


2011 ◽  
Vol 275 ◽  
pp. 204-207 ◽  
Author(s):  
Lenka Fusova ◽  
Pawel Rokicki ◽  
Zdeněk Spotz ◽  
Karel Saksl ◽  
Carsten Siemers

Nickel-base superalloys like Alloy 625 are widely used in power generation applications due to their unique properties especially at elevated temperatures. During the related component manufacturing for gas turbines up to 50% of the material has to be removed by metal cutting operations like milling, turning or drilling. As a result of high strength and toughness the machinability of Alloy 625 is generally poor and only low cutting speeds can be used. High-speed cutting of Alloy 625 on the other hand gets more important in industry to reduce manufacturing times and thus production costs. The cutting speed represents one of the most important factors that have influences on the tool life. The aim of this study is the analyses of wear mechanisms occurring during machining of Alloy 625. Orthogonal cutting experiments have been performed and different process parameters have been varied in a wide range. New and worn tools have been investigated by stereo microscopy, optical microscopy and scanning electron microscopy. Energy-dispersive X-ray analyses were used for the investigation of chemical compositions of the tool's surface as well as the nature of reaction products formed during the cutting process. Wear mechanisms observed in the machining experiments included abrasion, fracture and tribochemical effects. Specific wear features appeared depending on the mechanical and thermal conditions generated in the wear zones.


2021 ◽  
Author(s):  
Hüseyin Gürbüz ◽  
Şehmus Baday

Abstract Although Inconel 718 is an important material for modern aircraft and aerospace, it is a kind material, which is known to have low machinability. Especially, while these types of materials are machined, high cutting temperatures, BUE on cutting tool, high cutting forces and work hardening occur. Therefore, in recent years, instead of producing new cutting tools that can withstand these difficult conditions, cryogenic process, which is a heat treatment method to increase the wear resistance and hardness of the cutting tool, has been applied. In this experimental study, feed force, surface roughness, vibration, cutting tool wear, hardness and abrasive wear values that occurred as a result of milling of Inconel 718 material by means of cryogenically treated and untreated cutting tools were investigated. Three different cutting speeds (35-45-55 m/min) and three different feed rates (0.02-0.03-0.04 mm/tooth) at constant depth of cut (0.2 mm) were used as cutting parameters in the experiments. As a result of the experiments, lower feed forces, surface roughness, vibration and cutting tool wear were obtained with cryogenically treated cutting tools. As the feed rate and cutting speed were increased, it was seen that surface roughness, vibration and feed force values increased. At the end of the experiments, it was established that there was a significant relation between vibration and surface roughness. However, there appeared an inverse proportion between abrasive wear and hardness values. While BUE did not occur during cryogenically treated cutting tools, it was observed that BUE occurred in cutting tools which were not cryogenically treated.


1970 ◽  
Vol 2 (1) ◽  
Author(s):  
A.K.M.N. Amin, M.A. Rizal, and M. Razman

Machine tool chatter is a dynamic instability of the cutting process. Chatter results in poor part surface finish, damaged cutting tool, and an irritating and unacceptable noise. Exten¬sive research has been undertaken to study the mechanisms of chatter formation. Efforts have been also made to prevent the occurrence of chatter vibration. Even though some progress have been made, fundamental studies on the mechanics of metal cutting are necessary to achieve chatter free operation of CNC machine tools to maintain their smooth operating cycle. The same is also true for Vertical Machining Centres (VMC), which operate at high cutting speeds and are capable of offering high metal removal rates. The present work deals with the effect of work materials, cutting conditions and diameter of end mill cutters on the frequency-amplitude characteristics of chatter and on machined surface roughness. Vibration data were recorded using an experimental rig consisting of KISTLER 3-component dynamometer model 9257B, amplifier, scope meters and a PC.  Three different types of vibrations were observed. The first type was a low frequency vibration, associated with the interrupted nature of end mill operation. The second type of vibration was associated with the instability of the chip formation process and the third type was due to chatter. The frequency of the last type remained practically unchanged over a wide range of cutting speed.  It was further observed that chip-tool contact processes had considerable effect on the roughness of the machined surface.Key Words: Chatter, Cutting Conditions, Stable Cutting, Surface Roughness.


Author(s):  
K. V. Diadiun

Providing an increase in the working capacity of a metal-cutting tool, it is possible to significantly increase the productivity of mechanized labor, thereby reducing the cost of purchasing a new tool and saving on other accompanying technological components. During the operation of the cutting tool, the main load is transferred to its working part, this, as a rule, leads to partial wear or complete destruction of the planes and cutting edges. There are a number of technologies for processing working surfaces, which provides them with additional strengthening, the most effective of which is the method of applying special coatings to the surface of the cutting tool. Taking into account the specifics of the processes of formation of coatings, they can be divided into three main groups [1]. The first group includes methods in which the formation of coatings is carried out mainly due to diffusion reactions between saturating elements and structures of the instrumental material. The second group includes methods of forming coatings by a complex mechanism. The third group includes methods of forming coatings due to chemical and plasma-chemical reactions of particle flux simultaneously in volumes of space immediately adjacent to the saturable surfaces of the instrumental base. One such technology is the CIB (condensation and ion bombardment) method, which is a physical deposition of coatings. The most characteristic feature of coatings produced by this method is the absence of a transition zone between the coating and the tool material. This makes it possible to obtain a complex of properties on the working surfaces of the tool without deteriorating its original properties. The article is devoted to the issues of increasing the efficiency of ion-plasma technologies through the development and implementation of an automated system for analyzing and controlling the mass balance of reagent gases under conditions of several gases supply. Thus, the improvement of the technology of coating the working surfaces of the cutting tool, namely, the effective control of the process of applying ion-plasma coatings with the introduction of an automated system for analyzing and controlling the mass balance of reagent gases under conditions of supplying several gases is an urgent task.


Author(s):  
Nirmal S Kalsi ◽  
Rakesh Sehgal ◽  
Vishal S. Sharma

Due to the increase in complexity and expectations of more reliable solutions for a problem, the importance of multi-objective problem solutions is increasing day by day. It can play a significant role in making a decision. In the present approach, many combinations of the optimization techniques are proposed by the researchers. These hybrid evolutionary methods integrate positive characteristics of different methods and show the advantage to reach global optimization. In this chapter, Taguchi method and the GRA (Grey Relation Analysis) technique are pronounced and used to optimize a multi-objective metal cutting process to yield maximum performance of tungsten carbide-cobalt cutting tool inserts in turning. L18 orthogonal array is selected to analyze the effect of cutting speed, feed rate, and depth of cut using cryogenically treated and untreated inserts. The performance is evaluated in terms of main cutting force, power consumption, tool wear, and material removal rate using main effect plots of S/N (Signal to Noise) ratios. This chapter indicates that the grey-based Taguchi technique is not only a novel, efficient, and reliable method of optimization, but also contributes to satisfactory solution for multi-machining objectives in the turning process. It is concluded that cryogenically treated cutting tool inserts perform better. However, the feed rate affects the process performance most significantly.


Author(s):  
Salman Pervaiz ◽  
Sathish Kannan ◽  
Ibrahim Deiab ◽  
Hossam Kishawy

Metal-cutting process deals with the removal of material using the shearing operation with the help of hard cutting tools. Machining operations are famous in the manufacturing sector due to their capability to manufacture tight tolerances and high dimensional accuracy while simultaneously maintaining the cost-effectiveness for higher production levels. As metal-cutting processes consume a great amount of input resources and generate some material-based waste streams, these processes are highly criticized due to their high and negative environmental impacts. Researchers in the metal-cutting sector are currently exploring and benchmarking different activities and best practices to make the cutting operation environment friendly in nature. These eco-friendly practices mainly cover the wide range of activities directly or indirectly associated with the metal-cutting operation. Most of the literature for sustainable metal-cutting activities revolves around the sustainable lubrication techniques to minimize the negative influence of cutting fluids on the environment. However, there is a need to enlarge the assessment domain for the metal-cutting process and other directly and indirectly associated practices such as enhancing sustainability through innovative methods for workpiece and cutting tool materials, and approaches to optimize energy consumption should also be explored. The aim of this article is to explore the role of energy consumption and the influence of workpiece and tool materials towards the sustainability of machining process. The article concludes that sustainability of the machining process can be improved by incorporating different innovative approaches related to the energy and tool–workpiece material consumptions.


2018 ◽  
Vol 224 ◽  
pp. 01066
Author(s):  
Anton Seleznev ◽  
Anton Smirnov ◽  
Pavel Peretyagin

The work represents a new approach of preliminary surface treatment of replaceable polyhedral cutting ceramics inserts for significant increase of adhesion strength with deposited wear-resistant nitride ceramics. By this method the hydrojet treatment was used to repair surface defects occurring during manufacturing process of any required geometry of cutting inserts.


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