GlossaryKind of term: Manufacturing termCutting data
What is cutting data?
Cutting data are the settings a tool cuts with: cutting speed, feed, depth of cut and width of cut, chosen per tool, material and operation.
Cutting data are the process parameters of a machining operation. In milling they are the cutting speed vc in m/min, the feed per tooth fz in mm, the depth of cut ap and the width of cut ae in mm; in turning the feed per revolution f takes the place of fz. Spindle speed follows from n = vc × 1000 / (π × D), with D the tool diameter in mm, and feed rate from vf = fz × z × n, with z the number of teeth. Roughing and finishing use different values: roughing is about removal rate, finishing about size and roughness.
What does cutting data depend on?
The tool supplier gives starting values per material group and tool. What the machine can actually run also depends on spindle power and torque, the stiffness of machine, workholding and part, tool overhang, coolant, chip evacuation and the tool life you want. A higher cutting speed shortens cutting time but also tool life, and that relationship is empirical and strongly non-linear. A cutter in aluminium can usually run at a much higher cutting speed than the same cutter in austenitic stainless steel.
How does cutting data work in practice?
Cutting data and the length of the toolpath give the cutting time. For a first estimate without a toolpath, divide the volume to remove by the removal rate Q = ap × ae × vf / 1000 in cm³/min. Such an estimate is not a measured time: non-cutting time, tool changes, approach and retract moves, and lower values for thin walls or a long overhang come on top. Low values cost machining time, high values cost tool life and tooling. Whether a set of values works shows on the machine: in chatter, chip form, wear and the measured cycle time.
What is cutting data often confused with?
Cutting data are not machining time: they are the input, and the time follows only once the toolpath is known. Cutting speed is not spindle speed: cutting speed is how fast the edge moves along the material, spindle speed also depends on the diameter. And feed per tooth is not feed rate: the first is the advance per cutting edge, the second the speed of the tool relative to the part in mm/min.
How do you see cutting data in Blake?
In Blake machining time is its own line in the estimate, labelled as an estimate and costed at the machine's hourly rate. If that time differs from what you achieve with your own cutting data, you correct the line with a reason; who, when and why stay visible. More on estimating.
Frequently asked questions
Who sets the cutting data?
Usually the CAM programmer or the manufacturing engineer, starting from the tool supplier's data and experience with the shop's own machines. The operator adjusts them on the machine if the tool chatters, chips do not break or the finish disappoints.
Why not simply cut as fast as possible?
Because tool life drops sharply as cutting speed rises, and heat, chatter and chip evacuation set limits. Beyond a certain point, tooling, downtime and scrap cost more than the minutes gained. The chosen value is a trade-off, not a maximum.