Predictive Modeling and Optimization of High Performance Machining

2007 ◽  
Vol 10-12 ◽  
pp. 842-849
Author(s):  
Steven Y. Liang ◽  
Binti M. Abraham

High performance machining refers to the material removal operation that delivers the maximum achievable part quality, process competitiveness, and ecological compatibility through strategic utilization of cutters, machine tools, operation configuration, and process parameters. It is rapidly emerging as a prerequisite to productivity and profitability of machining operations and associated manufacturing systems. To accomplish high performance machining, a thorough understanding of the underlying mechanics that affect the performance attributes such as tool life, part integrity, air quality, etc., and how it is attributed to tooling conditions, operation configuration, and process parameters, is required. This paper reviews and summarizes a series of analytical methodologies by coupling with studies performed at the Georgia Institute of Technology for the quantitative modeling of fundamental mechanics of machining in the context of thermal, mechanical, tribological, and metallurgical effects and their interactions. In this study, cutting stresses, residual stress and tool life are explicitly described as functions of tool geometries, cutting speed, chip load, cutting fluid properties, interface tribological conditions, and the cutter/workpiece material constants. These analytical models facilitate the prediction of machining performance thereby allowing the optimal planning of machining processes in pursuing maximum performance. An array of experimental cutting data is also presented in comparison to model-based predictions for the validation of all aspects of the machining mechanics analysis.

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.


2015 ◽  
Vol 656-657 ◽  
pp. 243-250 ◽  
Author(s):  
Renann Pereira Gama ◽  
Marcos Valério Ribeiro

The increase of world requirements for improved products joined to growing competition between companies in the global market makes the same seek processes that ensure lower costs allied to high productivity and high quality product. Therefore, the great industrial and technological development has been increased the search for machining processes that promote, for example, high performance as regards the chip removal, less tool wear, failure and reduced impact on the environment. Regarding nickel-based superalloys, they have an extremely important role in the aeronautical and automotive industries among others. The nickel-based superalloy studied is the Nimonic 80A, hard machine material that has high mechanical strength and corrosion resistance on higher temperatures. The objective of this report is to study the influence of the application of cutting fluids in turning and the machining parameters in order to achieve high performance and optimization of machining this alloy. This one was machined using various machining parameters: cutting speed, feed rate, cutting depth, Minimum Quantity fluid (MQF), and Fluid abundant. After turning chip samples were obtained, was measured the surface roughness, volume of chip removed, cutting length and macro structural, some analyzes were performed and of lifetime of the tools were used in order to detect possible wear, as well as, microstructural observation of the chips by optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).On this report, we can observe the behavior of the materials and tools in the two cooling conditions used, and also, the impacts of the parameter variations in the surface finish, on the structure of the material and performance of the tools in respect chip removal regarding volume removed and machined length. Application by MQF was promising, but there is an abundant beyond the traditional application.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5011
Author(s):  
Cécile Escaich ◽  
Zhongde Shi ◽  
Luc Baron ◽  
Marek Balazinski

The TiC particles in titanium metal matrix composites (TiMMCs) make them difficult to machine. As a specific MMC, it is legitimate to wonder if the cutting mechanisms of TiMMCs are the same as or similar to those of MMCs. For this purpose, the tool wear mechanisms for turning, milling, and grinding are reviewed in this paper and compared with those for other MMCs. In addition, the chip formation and morphology, the material removal mechanism and surface quality are discussed for the different machining processes and examined thoroughly. Comparisons of the machining mechanisms between the TiMMCs and MMCs indicate that the findings for other MMCs should not be taken for granted for TiMMCs for the machining processes reviewed. The increase in cutting speed leads to a decrease in roughness value during grinding and an increase of the tool life during turning. Unconventional machining such as laser-assisted turning is effective to increase tool life. Under certain conditions, a “wear shield” was observed during the early stages of tool wear during turning, thereby increasing tool life considerably. The studies carried out on milling showed that the cutting parameters affecting surface roughness and tool wear are dependent on the tool material. The high temperatures and high shears that occur during machining lead to microstructural changes in the workpiece during grinding, and in the chips during turning. The adiabatic shear band (ASB) of the chips is the seat of the sub-grains’ formation. Finally, the cutting speed and lubrication influenced dust emission during turning but more studies are needed to validate this finding. For the milling or grinding, there are major areas to be considered for thoroughly understanding the machining behavior of TiMMCs (tool wear mechanisms, chip formation, dust emission, etc.).


2017 ◽  
Vol 882 ◽  
pp. 36-40
Author(s):  
Salah Gariani ◽  
Islam Shyha ◽  
Connor Jackson ◽  
Fawad Inam

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.


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.


1997 ◽  
Vol 119 (1) ◽  
pp. 86-94 ◽  
Author(s):  
D. A. Stephenson ◽  
P. Bandyopadhyay

Obtaining accurate baseline force data is often the critical step in applying machining simulation codes. The accuracy of the baseline cutting data determines the accuracy of simulated results. Moreover, the testing effort required to generate suitable data for new materials determines whether simulation provides a cost or time advantage over trial-and-error testing. The efficiency with which baseline data can be collected is limited by the fact that simulation programs do not use standard force or pressure equations, so that multiple sets of tests must be performed to simulate different machining processes for the same tool-workpiece material combination. Furthermore, many force and pressure equations do not include rake angle effects, so that separate tests are also required for different cutter geometries. This paper describes a unified method for simulating cutting forces in different machining processes from a common set of baseline data. In this method, empirical equations for cutting pressures or forces as a function of the cutting speed, uncut chip thickness, and tool normal rake angle are fit to baseline data from end turning, bar turning, or fly milling tests. Forces in specific processes are then calculated from the empirical equations using geometric transformations. This approach is shown to accurately predict forces in end turning, bar turning, or fly milling tests on five common tool-work material combinations. As an example application, bar turning force data is used to simulate the torque and thrust force in a combined drilling and reaming process. Extrapolation errors and corrections for workpiece hardness variations are also discussed.


Author(s):  
Arul Kulandaivel ◽  
Senthil Kumar Santhanam

Abstract Turning operation is one of the most commonly used machining processes. However, turning of high strength materials involves high heat generation which, in turn, results in undesirable characteristics such as increased tool wear, irregular chip formation, minor variations in physical properties etc. In order to overcome these, synthetic coolants are used and supplied in excess quantities (flood type). The handling and disposal of excess coolants are tedious and relatively expensive. In this proposed work, Water Soluble Cutting Oil suspended with nanoparticles (Graphene) is used in comparatively less quantities using Minimum quantity lubrication (MQL) method to improve the quality of machining. The testing was done on Turning operation of Monel K500 considering the various parameters such as the cutting speed, feed and depth of cut for obtaining a surface roughness of 0.462μm and cutting tool temperature of 55°C for MQL-GO (Graphene oxide) process.


2020 ◽  
Vol 4 (2) ◽  
pp. 45 ◽  
Author(s):  
Thomas Lakner ◽  
Marvin Hardt

The tribological effect of cutting fluids in the machining processes to reduce the friction in the cutting zone is still widely unknown. Most test benches and procedures do not represent the contact conditions of machining processes adequately, especially for interrupted contacts. This results in a lack of knowledge of the tribological behavior in machining processes. To close this knowledge gap, a novel experimental test bench to investigate the effects of cutting fluids on the frictional conditions in metal cutting under high-pressure cutting fluid supply was developed and utilized within this work. The results show that there is a difference between the frictional forces in interrupted contact compared to continuous contact. Furthermore, the cutting fluid parameters of supply pressure, volumetric flow rate, and impact point of the cutting fluid jet influence the frictional forces, the intensities of which depend on the workpiece material. In conclusion, the novel test bench allows examining the frictional behavior in interrupted cuts with an unprecedented precision, which contributes to a knowledge-based design of the cutting fluid supply for cutting tools.


2018 ◽  
Vol 249 ◽  
pp. 02003 ◽  
Author(s):  
Bhupinder Singh ◽  
Joy Prakash Misra

Cutting speed (CS) is a key performance measure to achieve optimal utilization of the WEDM process. However, input process parameters of WEDM and combination of wire and workpiece material greatly hamper CS and hence productivity and machining efficiency. Therefore, it is essential to pick the right combination of parameters and wire and workpiece material to obtain better CS. In this paper, four process parameters: Pulse-on time, Pulse-off time, Spark-gap voltage, and Peak current were chosen to develop an empirical model for CS during WEDM of Hastelloy C22 to provide a guideline to the potential users of the technique. This paper describes the response surface methodology (RSM) based mathematical modeling for average cutting speed. Furthermore, analysis of variance (ANOVA) was applied to find out significant process parameters and it was depicted that pulse on time and peak current were the major parameters affecting CS.


Author(s):  
Guangxian Li ◽  
Shuang Yi ◽  
Cuie Wen ◽  
Songlin Ding

Owing to its outstanding physical and mechanical properties, polycrystalline diamond (PCD) is ideal for cutting titanium alloys. However, the high temperature and stress caused by the interaction of tool surface and chip flow lead to different types of wear. This paper investigates the wear mechanisms of PCD tools in three different tribological regions: sticking zone, transition zone, and sliding zone, when machining titanium alloy Ti6Al4V. The tribological behavior of PCD tools in the wear processes were analyzed through both experiments and theoretical calculations. Analytical models of stresses and temperature distribution were developed and validated by turning experiments. PCD tools, consisting of diamond grains of different sizes: CTB002 (2 μm), CTB010 (10 μm), and CTM302 (2–30 μm), were used to cut Ti6Al4V at the normal cutting speed of 160 m/min and high cutting speed 240 m/min. It was found that adhesion, abrasion and diffusion dominated the wear process of PCD tools in different worn regions. Microscopic characters showed that the wear mechanisms were different in the three tribological regions, which was affected by the distribution of stresses and temperature. “Sticking” of workpiece material was obvious on the cutting edge, abrasion was severe in the transition zone, and adhesion was significant in the sliding zone. The shapes and morphological characters in different worn regions were affected by the stresses distribution and the types of PCD materials.


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