scholarly journals Closure to “Discussion of ‘A Three-Dimensional, Tool-Life Equation—Machining Economics’” (1959, ASME J. Eng. Ind., 81, p. 249)

1959 ◽  
Vol 81 (3) ◽  
pp. 250 ◽  
Author(s):  
Bertil N. Colding
Keyword(s):  
Tool Life ◽  
Three Dimensional ◽  
Machining Economics

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.

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.

Validation of Finite Element Modeling of Drilling Processes with Solid Tooling in Metals

2011 ◽  
Vol 223 ◽  
pp. 182-190 ◽  
Author(s):  
Lin Ma ◽  
Troy D. Marusich ◽  
Shuji Usui ◽  
Jon Wadell ◽  
Kerry Marusich ◽  
...  
Keyword(s):  
Finite Element ◽  
Tool Life ◽  
Large Strain ◽  
Three Dimensional ◽  
Time Frame ◽  
High Temperature Deformation ◽  
Burr Formation ◽  
Temperature Deformation ◽  
Hole Quality ◽  
Mechanical Coupling

Drilling is the source of major cost and time elements in airframe assembly due to hole quality, burr formation, and tool life problems plaguing the industry. Aerospace applications focus on holes for rivets loaded in shear in aluminum, titanium and composite stack-ups. Optimal chip flow and tool life are often in competition with burr formation, general hole quality, and cycle time. Physics-based modeling of drilling processes can provide insight and information not readily available or easily obtained from experiments, and in a much faster time frame. A three-dimensional finite element-based model of drilling is presented which includes fully adaptive unstructured meshing, tight thermo-mechanical coupling, deformable tool-chip-workpiece contact, interfacial heat transfer across the tool-chip boundary, and constitutive models appropriate for high strain-rate, large strain and high temperature deformation.

A Parametric Analysis of the Undeformed Chip Geometry in Gear Hobbing

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Lars Vedmar ◽  
Carin Andersson ◽  
Jan-Eric Ståhl
Keyword(s):  
Tool Life ◽  
Three Dimensional ◽  
Chip Thickness ◽  
Accurate Method ◽  
Manufacturing Method ◽  
Differentiable Functions ◽  
Cross Section Area ◽  
Involute Gears ◽  
Increase Tool Life ◽  
Chip Geometry

Hobbing is a common manufacturing method when producing helical, involute gears. In order to increase tool life and surface finish, an accurate method to determine chip geometry is needed. Although this accurateness may involve numeric solutions, the geometric description must, as far as possible, be analytic and give a description of the continuously changing chip geometry. In this report, the cutting edges of the tool are mathematically described using parametric and analytically differentiable functions. This gives the possibility to determine the geometry of the three-dimensional surface on the blank each cutting edge will cut with numeric approximations kept to a minimum. By comparing successively cut surfaces, the chip geometry is determined using the tool and process parameters. The mathematical description gives the possibility to calculate the required characteristic properties of the chips. These are needed for increasing the tool life in order to develop more efficient tools and processes. An example is given in which characteristics, as the maximum chip thickness, the chip cross-section area, and the mean chip thickness are calculated. The reported theory describes in detail how the chip geometry is determined.

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