Search results for " cutting"

Improving the dynamic behavior and working accuracy of the CNC laser cutting machines

2012

CNC laser cutting machines are widely encountered in the manufacturing workshops. The dynamic behavior and working accuracy of these machines decreases in time, due to normal wear and intensive use. Consequently, a process or re-tuning the control parameters is required and it has to be performed at the workshop level. The paperwork presents a joint simulation and experimental process for improving the accuracy of CNC laser cutting machines. The approach is focused on the capability of the machine to cut rectangular corners.

The mechanics of continuous chip formation in oblique cutting with single-edged tool—part II. Experimental verification of the theory

1990

Abstract Experimental results obtained during oblique cutting of annealed steel Ck 45 (SAE-AISI 1045) with a single-edged tool are presented. Extensive measurements of forces, cutting ratio, chip flow angle etc. have been carried out under a wide range of cutting conditions. The measured data obtained from these cutting tests are used to test assumptions proposed in the first part of this work. In relation to previous works dealing with oblique cutting problems the present one extends to tools with angles of tool obliquity ranging from 30° to 70° and having a large negative rake angle.

Wear modelling in mild steel orthogonal cutting when using uncoated carbide tools

2007

Abstract Wear prediction in machining has been recently studied by FEM although the use of numerical methods for such applications is still a very challenging research issue. In fact, wear phenomenon involves many aspects related to process mechanics which require a very accurate modelling. In other words, only a very punctual code set-up can help the researchers in order to obtain consistent results in FE analysis. The high relative velocity between chip and tool requires effective material models as well as friction modelling at the interface. Moreover the prediction of temperature distribution is another critical task; in the paper some different procedures are discussed. Subsequently a …

Non-Waste Technology for Utilization of Tree Branches

2022

The trees (e.g., fruit or decorative) growing on the homestead plots of private households provide opportunities for sustainable biomass obtained from pruned branches every year. Profitable production of fuel material requires high-performance equipment and methods by which wood chips can be produced at low cost. The practice of chopping tree branches shows that not all chopping machines are suitable for use on homestead plots. This research gives the five-year test results of a developed and patented tree branch chopping machine under special operating conditions. The machine was tested under the conditions of the homestead plot of a private household in the Poltava region, and the enginee…

Propagation techniques for Iberis semperflorens L.

2009

Effects of Rapid Weight Loss on Kidney Function in Combat Sport Athletes

2021

Even though scientific literature shows numerous heath complications and performance decrements associated with rapid weight loss (RWL), its prevalence remains exceedingly high across various combat sports. The aim of this study was to thoroughly search the existing literature to explore the influence of RWL on kidney function in Olympic and non-Olympic combat sport athletes. PubMed and Web of Science were searched for the relevant studies. Only original articles published from 2005 onwards, written in English, that included healthy males and females who prompted ~5% weight loss within a week or less, were included in the study. Retrieved studies showed that creatinine, blood urea nitrogen …

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.

Positron Annihilation Study of Defects Induced by Various Cutting Methods in Stainless Steel Grade 304

2011

We report in this article the comparison of the subsurface zones (SZs) in austenitic stainless steel 304 samples created by three cutting techniques, i.e., the laser cutting (LC), abrasive water jet (AWJ), and traditional milling cutting (MC). The crystal lattice defects distribution in this zone were investigated using the positron annihilation method. It was shown that the MC creates the great number mainly edge dislocations decorated by vacancies. Their concentration decreases with the increase of the depth from the cut surface. The total depth of the SZ is extended up to 150 μm from the cut surface. Similar dependency was observed for the AWJ machining but the total depth is much lower,…

Tribology of Metal Cutting

2008

This chapter provides comprehensive knowledge regarding tribological behaviour of the cutting zone and characterizes specific features of the tool–chip contact that influence friction mechanisms in this area. Adhesion, plastic deformation of contacting asperities and ploughing action of the cutting edge are selected as three predominant mechanisms controlling sliding friction between the tool and the chip. The two-zone model of the tool–chip contact distinguishing seizure and sliding regions is characterized, along with experimental evidence based on photoelastic and material flow line techniques. Corresponding stress distributions for plane and restricted-contact cutting tools are provided…

The effect of wear on the tetragonal-to-monoclinic transformation and the residual stress distribution in zirconia-toughened alumina cutting tools

1998

Abstract Zirconia-toughened alumina cutting tools have been examined after machining an AISI 1040 steel. The Raman spectrum of zirconia and the fluorescence spectrum from alumina have been used to determine the extent of the tetragonal-to-monoclinic (t-m) transformation and the residual stresses in and around the worn-out crater, respectively. Although about 15% vol. m-zirconia is present even in a brand new cutting tool, it was shown that the crater region undergoes the t-m transformation up to 40% vol. In both cases, the transformed zone is concentrated near the surface. The residual stresses in alumina are slightly compressive in the new cutting tool and away from the crater region, but …