Economic Cutting Speed
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Economic Cutting Speed
Economic Cutting Speed - An increase of cutting speed has two main effects upon the economics of cutting; the metal removal rate is increased, the tool life is decreased. An increase in the metal removal rate will lower the direct cost of metal removal; a reduction in the tool life will increase the costs of servicing and replacing worn out tools.
The two separate effects, and their combined influence upon the total cost of machining.
(a) As V increases, the time required to remove the metal (and hence the cost of its removal) will fall. The cost of cutting ∞ 1/V.
(b) As V increases, the tool life T falls. The costs of tooling ∞ 1/T but by
Taylor's equation, 1/T = [V/C]1/n and since C is a constant, the costs of tooling ∞ V 1/n.
(c) The inclusive costs of machining will be the sum of the separate costs, and by addition of the separate cost values for each value of V shown, a third graph or curve drawn dotted change of the inclusive cost with respect to changes in cutting speed is obtained. This graph has a minimum value for inclusive cost, and the ideal (or optimum) cutting speed is the value of V at the minimum point.
Since tooling costs can be seen to depend upon the value of II, it would appear that this exponent is important in relation to the economics of metal cutting.
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