Search results for "Machining"

Machining Economics and Optimization

2008

This chapter provides comprehensive knowledge regarding economical considerations and possible optimization methods of machining operations. The background of machining economics, including costs, time and productivity, related for typical machining operations (such as turning, milling and drilling) is outlined. The components of machining costs and time related to the cutting speed are distinguished, and appropriate mathematical models are presented. Optimization procedures allowing selection of optimal values of cutting speed and feed rate based on tool life and energy efficiency criteria are overviewed. In the first case, the economic cutting speed and cutting speed corresponding to the …

Off-line path correction of robotic face milling using static tool force and robot stiffness

2015

In this paper the developed method for off-line compensation of tool deflections when milling aluminum with an industrial robot is presented. The efficiency of this approach is verified with high precision measurements of deflections using a laser tracker. The compensation method includes both the static milling process model which can predict the mean value components of the tool forces and a new combined local/global approach for estimating the combined stiffnesses of joints. With a process model such as the one presented in this paper and estimates of the robot's joint stiffness values, the tool path can be adjusted to counteract deflections of the tool during milling operations. The mod…

Sensor-Assisted Machining

2008

This chapter provides comprehensive knowledge regarding the application of various sensors and monitoring techniques to machining processes, cutting tools and machine tools. A number of monitoring methods used in manufacturing and relevant sensors are characterized. In particular, three most frequently used sensors, i.e., force, acceleration and acoustic emission, are presented and their characteristics and advantages are highlighted. The architectures of multiple-sensor tool-monitoring systems for detection of tool wear and breakage and collision for machine tools, including details of sensor fusion, signal processing and decision-making, are presented. Moreover, the concepts of sensor-bas…

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.

The mechanics of continuous chip formation in oblique cutting with single-edged tool — Part I. Theory

1990

Abstract The paper presents a new point of view on oblique cutting mechanics when cutting with a single-edged tool. This is based on the main assumption that plastic flow of material during chip forming occurs in the set of planes normal to the cutting edge. As a consequence of the transformation of various orthocartesian systems some new generalized relationships for kinematics of oblique cutting operation and plastic deformation in the shear zone are derived.

Analytical Models Based on Composite Layer for Computation of Tool-Chip Interface Temperatures in Machining Steels with Multilayer Coated Cutting Too…

2005

In this study the method of elementary balances (MBE) is applied to predict the temperature fields in uncoated and coated carbide cutting tools. Numerical computations are supported by the experimentally/analytically obtained values of the contact length, the total heat flux and the heat partitioning. The changes in the tool temperature maps, resulting from variable thermal properties of tested materials are considered. In particular, the distribution of temperature across the thin film of 0.01 mm and corresponding temperature rise distribution curves along the rake and flank faces are completely displayed. The simulations have been validated against the measured average rake face temperatu…

Cost Analysis of FMS Throughput

1988

Abstract The need for an effective cost planning and control system is stressed in today highly competitive manufacturing environment. The conventional approaches of machining economics to cost analysis are no more able to cope with the new structure of the production costs in the highly automated - highly integrated manufacturing systems. Suitable cost analysis procedures should provide a strong integration between process planning data and overall system performances. The here proposed procedure for the estimate of the unit manufacturing cost in FMSs achieves this integration by using performance evaluation techniques like discrete event simulation or queueing network models.

Prediction of Tool Wear in Machining

2007

On the effectiveness of Finite Element simulation of orthogonal cutting with particular reference to temperature prediction

2007

Abstract Finite Element simulation of orthogonal cutting is nowadays assuming a large relevance; in fact a very large number of papers may be found out in technical literature on this topic. In recent years, numerical simulation was performed to investigate various phenomena such as chip segmentation, force prediction and tool wear. On the other hand, some drawbacks have to be highlighted; due to the geometrical and computational complexity of the updated-Lagrangian formulation mostly used in FE codes, a cutting time of only a few milliseconds can be effectively simulated. Therefore, steady-state thermal conditions are not reached and the simulation of the thermal phenomenon may be ineffect…

A simple inverse procedure to determine heat flux on the tool in orthogonal cutting

2006

The applications of numerical simulation to machining processes have been more and more increasing in the last decade: today, a quite effective predictive capability has been reached, at least as far as global cutting variables (for instance cutting forces) are concerned. On the other hand, the capability to predict local cutting variables (i.e. stresses acting on the tool, temperature distribution, residual stresses in the machined surface) has to be furtherly improved, as well as effective experimental procedures to validate numerical results have to be developed. The aim of this paper is the proposition of an innovative approach, based on an simple inverse procedure, in order to identify…