Machining operation type. Determines which speed/feed lookup and MRR formula to use.

Workpiece material name (e.g., '6061-T6 Aluminum', '304 Stainless', '4140 Alloy Steel'). Used to look up recommended cutting parameters from the speeds-feeds table.

Cutting tool material or type (e.g., 'carbide', 'hss', 'ceramic', 'diamond', 'indexable'). Affects recommended cutting speed and default tooth count. If omitted, defaults to 'carbide'.

Workpiece or hole diameter in inches. Required for turning, boring, drilling, reaming, and tapping. Typical range: 0.125-24 in. Only required when operation is turning, boring, drilling, reaming, or tapping.

Cutter diameter in inches for milling operations. Required for milling if workpiece_diameter_in is not provided. Typical end mills: 0.125-2 in; face mills: 2-8 in. Only required when operation is milling and workpiece_diameter_in is not provided.

Total length of cut in one pass, in inches. For facing: use workpiece diameter. Used to calculate cycle time.

Axial depth of cut in inches. If omitted, looked up from table or defaulted (0.100 in roughing, 0.020 in finishing). Typical roughing: 0.050-0.250 in.

Radial width of cut in inches (milling only). Defaults to full cutter diameter if omitted. Reduce for climb milling or slotting passes.

Number of cutting teeth/flutes on the milling cutter. Defaults by tool type (typically 4 for carbide/HSS, 6 for indexable). Only used in milling. If omitted, defaults to a typical value by tool type (4 for carbide/HSS, 6 for indexable).

Type of cut pass. Roughing uses higher depth of cut and lower speed; finishing uses lower depth of cut and higher speed for better surface finish. If omitted, defaults to 'roughing'.