A relationship exists between the cutting speed and the cost per piece. Between the minimum total cost and the minimum time per piece is a high efficiency machining range.
Minimum total cost and minimum time per piece are the boundaries of the high efficiency machining range.
The accountants and engineers agree- this is the “sweet spot” of our operations.
We know the sweet spot when we encounter it!
Higher speeds permit quicker operating sequences, reducing time per piece; but higher speeds reduce tool life and increase down time.
Plotting both Total Cost per Piece and Total Time per Piece as curves shows that the high efficiency range exists between the two curves’ minima.
Minimum time per piece usually occurs at higher speeds than minimum cost, providing higher operating efficiency.
If you have plenty of open capacity, you should aim for minimum part cost.
If you are capacity constrained, perhaps lowest cost per part is not optimum for your shop.
Graph and discussion based on AISI Cold Finished Steel Bar Manual 1968- what I trained on when I entered the market.
Speaking of Precision Blog 