Closure to “Discussion of ‘Machining Economics and Tool Life Variation—Parts 1 and 2’” (1978, ASME J. Eng. Ind., 100, pp. 401–402)

1978 ◽  
Vol 100 (4) ◽  
pp. 402-402
Author(s):  
R. Levi ◽  
S. Rossetto
Keyword(s):  
Tool Life ◽  
Machining Economics

Adaptive Tool Replacement Policies in Machining Economics

1996 ◽  
Vol 118 (4) ◽  
pp. 658-663 ◽  
Author(s):  
E. Iakovou ◽  
C. M. Ip ◽  
C. Koulamas
Keyword(s):  
Tool Life ◽  
Cutting Speed ◽  
Control Policy ◽  
Replacement Policy ◽  
Machining Process ◽  
Time To Failure ◽  
Preventive Replacement ◽  
Machining Economics ◽  
Production Run ◽  
Tool Replacement

Optimization of the economics of machining comprises the determination of the optimal cutting speed and tool replacement policy. A necessary input to the above approach is knowledge of the parameters of the tool life equation which links tool life to cutting speed. In reality, these parameters are not known and should be estimated based on actual machining data. This paper addresses the above optimization problem in the framework of an adaptive control policy. Replacement times in one production run are used to estimate the mean-time-to-failure of a tool, which is in turn used in a regression model to update estimators of the tool life parameters. Using the newly updated estimates a new cutting speed and preventive replacement policy are then determined for the next production run. The end result is an easily implementable decision making tool which can aid in the continuous improvement of the machining process.

A Three-Dimensional, Tool-Life Equation—Machining Economics

1959 ◽  
Vol 81 (3) ◽  
pp. 239-249 ◽  
Author(s):  
Bertil N. Colding
Keyword(s):  
Tool Life ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Minimum Cost ◽  
Optimum Combination ◽  
Depth Of Cut ◽  
Nose Radius ◽  
Edge Angle ◽  
Machining Economics ◽  
General Tool

In Part 1 of this paper, two tool-life equations are derived, one limited equation and one general tool-life equation, between the variables cutting speed, chip equivalent, and tool life. The chip equivalent, introduced by Woxén, is a well-defined function of feed, depth of cut, nose radius, and side-cutting-edge angle. The limited equation takes into account the variation of Taylor’s exponent n with the value of the chip equivalent, but the equation is only valid within certain limits of cutting speed and chip equivalent. A general equation is then derived on the basis of the limited equation. In Part 2 an expression called the productivity is derived. This relationship is valid for either maximum production or minimum cost and, combined with the general, hyperbolic, tool-life equation, it is used to investigate the optimum combination of tool-life, cutting speed, and chip equivalent.

Constrained Cutting Rate-Tool Life Characteristic Curve, Part 2: Convex Programs

1998 ◽  
Vol 120 (1) ◽  
pp. 160-165 ◽  
Author(s):  
C. L. Hough ◽  
Y. Chang
Keyword(s):  
Sensitivity Analysis ◽  
Tool Life ◽  
Simplex Method ◽  
End Milling ◽  
Characteristic Curve ◽  
Convex Programs ◽  
Machining Economics ◽  
Cutting Rate ◽  
Primal Dual ◽  
Simplex Tableau

Based on the concept in Part 1, Theory and General Case, algorithms to determine the constrained R-T characteristic curve are established for convex constrained machining economics problems. The first algorithm is for posynomial problems with the linear-logarithmic tool life equation. The R-T curve may be determined by applying the simplex method to the log-dual problems. Sensitivity analysis of the optimal simplex tableau enables obtaining the loci of optima easily. The second algorithm is for the quadratic posylognomial problems with quadratic-logarithmic tool life equation using the property of primal-dual feasibility. End milling examples constructed in Part 1 illustrate the algorithm comparing to the exhaustive method.

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