Definition
Cutting speed is the speed at which the cutting edge of a tool moves relative to the workpiece material, typically expressed in surface metres per minute. It is set based on the material being cut, the tool material and coating, and is one of the core parameters, alongside feed rate, that determines both cycle time and tool wear.
Why cutting speed is a trade-off, not just 'faster is better'
Pushing cutting speed higher generally cuts faster but wears the tool out sooner, and past a material- and tool-specific limit, accelerates tool wear and heat generation sharply rather than gradually, which is why cutting speed is chosen from established data, not maximized blindly.
Where cutting speed is decided
Not on the drawing; it's a process parameter chosen by the programmer or work preparer based on material, tool and desired tool life, not something an engineer specifies.
Common mistakes
Assuming a higher cutting speed is always a free win. Beyond the appropriate range for a given material and tool, tool wear and heat rise sharply, which can cost more in tool replacement and rework than the time saved.
Pushing cutting speed higher generally cuts faster but wears the tool out sooner, and past a material- and tool-specific limit, accelerates tool wear and heat generation sharply rather than gradually, which is why cutting speed is chosen from established data, not maximized blindly.
See how Blake reviews a partFrequently asked questions
Who decides cutting speed?
Typically the CNC programmer or work preparer, based on published or experience-based data for the specific material and tool combination.
Does cutting speed alone determine cycle time?
No, feed rate, depth of cut and toolpath strategy all combine with cutting speed to determine actual cycle time.
Why not always cut at the fastest possible speed?
Because tool wear and heat generation rise sharply past a material- and tool-specific limit, which can cost more in tool changes and quality issues than it saves in time.