Peck Drilling
When should I use peck drilling instead of a straight drill cycle?
Use peck drilling when chip evacuation is the limiting factor: deep holes, gummy materials, poor coolant access, or long chips that do not self-break.
What is the main difference between G73 and G83?
G83 fully retracts to clear chips; G73 only backs off slightly, so it is faster but less aggressive at chip clearing.
Why does peck drilling improve tool life?
It reduces chip recutting, lowers heat at the cutting edge, and prevents flute overload that would otherwise spike cutting forces and damage the drill.
Peck drilling is a CNC drilling method where the tool advances in short incremental cuts, then retracts partially or fully to break chips, clear swarf, and reduce heat before continuing. It is commonly implemented with G83 (full retract) or G73 (small retract) to control chip evacuation in deep holes or difficult materials.
On the shop floor, peck drilling is essential when hole depth exceeds about three times the drill diameter, or when materials like aluminum, stainless, or titanium produce long, stringy chips that can pack flutes and cause tool failure. The cycle prevents chip packing, birdnesting, and overheating by breaking chips into manageable segments. Programmers set peck depth, retract amount, and coolant strategy to balance chip evacuation against cycle time—shorter pecks improve chip control but increase non-cutting motion, while longer pecks risk clogging and load spikes. In production, operators monitor spindle load, chip color, and sound to adjust parameters. The choice between G83 and G73 depends on material and depth: G83 fully retracts to clear chips aggressively, ideal for deep or gummy materials; G73 retracts only slightly, offering faster cycles but less chip clearing. This balance is critical in high-volume parts to maintain tool life and hole quality without sacrificing cycle time.
Chip packing in flutes: When pecks are too long or retracts too shallow, chips stay trapped, raising torque and temperature until the tool rubs, squeals, or breaks—common in aluminum stringers and ductile materials.
Excessive retract distance: Using G83 when G73 suffices wastes time on every peck, increasing cycle time and causing positional inconsistency if the fixture has looseness, due to repeated retract/re-entry cycles.
Wrong peck strategy for material: An aggressive peck in hard alloys or work-hardening stainless causes built-up edge and flute packing; too conservative a peck leads to rubbing and poor hole quality, with oversize holes or broken tips.