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Machining

Drilling speed, feed and cycle-time estimate

Start with a cutting speed and feed recommended for the work material, drill material, diameter and hole condition. Convert those inputs into spindle speed and feed rate, then check whether the real machine, clamping and chip evacuation can support them.

QuantityRelationshipUse
Spindle speedn = 1,000 · vc / (π · d)Use vc in m/min and drill diameter d in mm to obtain rev/min.
Feed ratevf = n · fFeed per revolution f becomes the axial feed rate in mm/min.
Cutting timetc = L / vfUse the effective drill travel L, including approach and breakthrough allowance where applicable.
Chip area per edgeA = d · f / 4Links diameter and feed to the force calculation introduced in the cutting-force reference.
ILLUSTRATIVE ESTIMATE

Ø10 mm through-hole

Assume a validated starting value of vc = 25 m/min and f = 0.15 mm/rev. The calculation gives n ≈ 796 rev/min; at a selected 800 rev/min, vf = 120 mm/min. For an effective travel of 24 mm, ideal cutting time is about 0.20 min or 12 s, before approach, retract, pecking or tool-change time.

DRILL SELECTION

Match geometry to chip behaviour

  • A normal-helix drill is the general starting point for common steels.
  • A small helix suits brittle, short-chipping materials.
  • A large helix helps with soft, long-chipping materials.
  • Confirm point geometry, coating and coolant strategy with current tool-maker data.
SourcesSource basis: Ulrich Fischer et al., Mechanical and Metal Trades Handbook, 3rd English edition, drilling section beginning on print p. 298; drill geometry and standard-value logic cross-checked against the corresponding 2nd-edition drilling section, p. 301. Formula example and travel allowance are an original application summary.
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