Search results for "Machining"
showing 10 items of 180 documents
Friction behaviour of heat isolating coatings in machining: mechanical, thermal and energy-based considerations
2003
Abstract This paper deals with possible modifications of the frictional behaviour exhibited during the cutting process resulting from the influence of the most-commonly used heat isolating coatings deposited on a WC-Co carbide substrate. For this study, three- and four-layered coatings with intermediate Al 2 O 3 ceramic layer and a monolayer TiAlN coating, which offer superior thermal protection of the carbide substrate, were examined. Orthogonal cutting tests were carried out by end-turning medium carbon steel and austenitic stainless steel workpieces. The experimental study was aimed at determining the fundamental frictional characteristics: dimensions of the tool-chip contact area, the f…
Prediction of Tool Wear Progress in Machining of Carbon Steel using different Tool Wear Mechanismsl
2008
In this paper the prediction of tool wear on carbide uncoated tools was taken into account. In particular, two different tool wear models based on the diffusion mechanism and on the abrasion mechanism were considered. The calibration of the utilized models was done using the results obtained by experimental analysis performed on an orthogonally machined AISI 1020 tube. Once the calibration was executed, numerical simulations, for both the utilized tool wear models, were simultaneously performed with the aim to test the capability of the proposed numerical procedure. The comparison between the two tool wear mechanisms for predicting the flank tool wear is discussed in the paper.
The role of coatings in controlling the cutting process when turning with coated indexable inserts
1998
Abstract This paper is concerned with the variations in the specific cutting pressure and the tool–chip interface temperature that occur when machining a medium carbon steel and an austenitic stainless steel with TiC-, TiC/TiN- and TiC/Al2O3/TiN- coated inserts. Extensive experimental studies involving the cutting force and the interface temperature were performed. A standard thermocouple embedded in the workpiece was used to determine the cutting temperature. Two new parameters were introduced in order to compare both the mechanical and thermal loadings of the tool–chip contact for coated flat-faced and grooved inserts. Some optimal coating structures for high speed machining of these stee…
Study of Coating/Work Material Interaction in Turning with Chip Forming Inserts
1997
This paper presents some interesting and novel results of an experimental study on the influence of the coating structure on the behaviour of the tribo-contact between the tool and the chip. The experiments involved TiC, TiC/TiN and TiC/Al2O3/TiN — coated flat-faced and grooved inserts in conjunction with a medium carbon steel and an austenitic stainless steel. Extensive experimental studies involving the cutting force and the tool-chip interface temperature were carried out. Two new parameters were introduced in order to compare both the mechanical and thermal loadings of the tool-chip contact for the two shapes of the rake face. Some optimal coating structures for high speed machining of …
Metallurgical Evolutions in Hot Forging of Dual Phase Titanium Alloys: Numerical Simulation and Experiments
2015
Titanium forging has been encountering a growing interest in the scientific and industrial communities because of the distinct advantages it provides with respect to machining, in terms of both mechanical properties of the product and material waste, thus significantly reducing the Buy to Fly ratio. In the paper, a numerical FE model, based on a tri-coupled approach and able to predict the microstructural evolutions of the workpiece during the process, is developed and set up. Calculated results are compared to experiments for a few industrial case studies. The final phases distribution in the forged parts is experimentally measured and compared to the FE model output finding satisfying ove…
Investigation of Critical Points of Pore Formation Voltage on the Surface of Semiconductors of A3B5 Group
2021
In this work, critical values of pore-formation in electrochemical machining of semiconductors of A 3 B 5 group are studied. On the example of indium phosphide, the indicators of the series of dependence of current density on the voltage of anodization are studied. The rates of current density increase in the regime of gradual rise of anodization voltage are determined. According to these indicators, the intervals are established, within which the active pore-formation occurs on the surface of semiconductor.
Machinability of Engineering Materials
2008
Chapter 13 provides comprehensive knowledge regarding machinability of construction materials and characterizes various meanings of this specific material feature, allowing effective selection of machining conditions. Factors affecting machinability and typical causes of low machinability are discussed. Three groups of machinability criteria are selected, including basic, substitutive and auxiliary ones. In particular, the cutting speed corresponding to economic or high productivity criteria and obtainable surface roughness are distinguished as basic machinability criteria. Relative and absolute machining rating systems are highlighted, and appropriate material groups and values of the mach…
Influence of machining conditions on friction in metal cutting process – A review
2019
This paper presents a range of variable machining factors which influence substantially friction directly or by the tool wear developed in the cutting zone. The group of direct factors include the workpiece and cutting tool materials coupled, the cutting/sliding velocity, cooling media supplied to the tool-chip contact zone, modification of the tool contact faces by micro-texturing. Special attention was paid to the tool wear evolution and its pronounced effect on changes of the contact conditions.
Modeling the machined surface quality of an aluminum alloy using the active experiment type
2019
Abstract The surface roughness obtained by the cutting processes has always been a subject of great interest when it is intended to improve the quality of the final product requested by the customer. The objective of this scientific paper involves a comparative study on the tracking of the surface roughness measured both longitudinally and transversely in the direction of the cutting feed movement, following the end-milling process of an aluminum alloy used in the aerospace industry worldwide. Practical experiments have conducted in a prestigious company in the aerospace industry of Romania. Regarding the cutting regime, in terms of milling, a cutting speed was adopted to maintain its const…
Experimental investigation of the influence of adhesion on the frictional conditions in the cutting process
1999
Abstract This paper presents the results of an experimental study on the influence of adhesion on the tribological characteristics of the tool-chip interface. It was established that under orthogonal cutting conditions both the high interface temperature and severe plastic deformation result in relatively strong adhesion between steel and uncoated carbide. In particular, the molecular–mechanical theory of friction was applied to estimate the shear strength of the local adhesive junction, and to divided the rake face friction into two terms—an adhesion term (the interfacial coefficient of friction) and the deformation term. It should be pointed out that the data obtained provide a new approa…