The economics of precision machining can be understood with just 4 factors- Machining Cost, Material Cost, Tool Cost, and Cost of Non-productive Time (Set-up Costs).
The line labeled “machining cost” (which is made up of labor and overhead cost of time per piece) reduces with increasing speed by reducing operating (cycle) times.
The cost for tools, on the other hand, increases with increasing speed. This is because tool life decreases with increasing speed.
Since machining and tool costs vary with the speed of operation, a minimum total cost occurs at a definite set of conditions for material, tooling and operating speed.
Purchasing improved tools is one way to move the machining cost and total cost per piece curves to the right and down. As is adding coatings, improved metalworking fluids and their delivery, etc..
As long as the gain in speed and the resultant drop in cost to produce are larger than the cost of the improved tooling, or other process improvements, you can improve or further optimize the economics of your production.
Our industry has benefited greatly from the many improvements in tool materials, coatings, metalworking fluids and design improvements.
Are you taking full advantage?
Graph and discussion based on AISI Cold Finished Steel Bar Manual 1968