The rate of return method also called return-on-investment (ROI) method,goes slightly beyond the present worth (PW) and uniform annual cost (UAC) methods by actually calculating the rate of return that is provided by the investment.If the calculater rate is greater than the criterion rate of return,the investment is acceptable.
To determine the return on investment,an equation must be set up with the rate of return as the unknown.Either the PW method or the UAC method can be used to establish the equation.Then the value of the interest rate i that drives the aggregate PW of UAC to zero is determined.
(Groover M.,Automotion,Production Systems and CIM Practice Hall 1st edition,p. 50)
Present worth method
The present worth method uses the equivalent present value of all current and future cash flows to evaluate the investment proporsal.The future cash are converted into their present worth by using the appropriate interest factors.Accordingly,some ,nterest rate must be used in the factors.This interest rate is decided in advance and represents the rate-of-return criterion that the company is using to evaulate its investment opportunities.If the aggregate present worth of the project is positive,the return from the project exceeds the rate-of-return criterion.If the present worth of the project is negative,the project does not meet the rate-of-return criterion.
(Groover M.,Automotion,Production Systems and CIM Practice Hall 1st edition,p. 49)
Boring Cycle (G85 Code)
The boring operation requires that the tool move at a programmed feedrate when it is between points R and Z.The format of the statement for calling the boring cycle subroutine is G85XxYyZzRrFfLl
(Chang C.H., Melkonof M.A.,NC Machine Programming and Software Design Practice Hall,p.48)
Facing Cycle (G94 Code)
Facing is an operation used to reduce the length of a turned part as opposed to turning operation whose function is reduce its diameter.
(Chang C.H., Melkonof M.A.,NC Machine Programming and Software Design Practice Hall,p.51)
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