G73 is a high-speed peck drilling cycle used for shallow to medium-depth holes where chips need to be broken quickly without retracting completely out of the hole. Unlike G83, which performs full retracts to the R plane, G73 uses rapid miniature pecks that break chips efficiently while maintaining high feedrates and reducing cycle time. This makes G73 ideal for soft materials like aluminum and brass, as well as high-speed drilling in steels where chip evacuation is not critical. It is widely used in automotive, aerospace, moldmaking, and general machining where hundreds or thousands of drilled holes must be produced per day.
1. What Makes G73 Different from G83?
G73 (High-Speed Peck)
- Shallow retract (minimal lift)
- Extremely fast cycle
- Designed for chip break, not clearing
- Best for holes < 3×D
- Ideal for aluminum, brass, mild steel
G83 (Deep Hole Drill)
- Full retract to R plane
- Designed for chip evacuation
- Best for deep holes (> 3×D)
- Crucial for stainless, titanium, Inconel
G73 = high-speed drilling
G83 = deep drilling
2. Basic G73 Syntax (Fanuc/Haas Standard)
G73 X# Y# Z# R# Q# F#
Where:
- X/Y → drilling location
- Z → final depth
- R → retract plane
- Q → peck amount
- F → feedrate
Example:
G73 X30. Y20. Z-12. R2. Q2. F250
Meaning:
– Peck 2 mm at a time
– Very fast shallow retracts
– Efficient chip breaking
3. Real Production Example – High-Speed Aluminum Drilling
G90 G54
S4500 M03
G73 X20. Y30. Z-10. R1. Q4. F400
X40. Y30.
X60. Y30.
G80
Perfect for mass-production hole patterns.
4. G73 for Steel (Medium Depth, Controlled Chips)
For materials where chips can still be long:
G73 X50. Y18. Z-18. R1. Q1.5 F180
Small Q values = smarter chip breaking.
5. G73 with Carbide Drills (High-Speed Machining)
Carbide drills perform best with small, fast pecks:
G73 X70. Y42. Z-15. R1. Q0.8 F220
This prevents micro-welding on the cutting edges.
6. G73 + G98/G99 Usage
G98 → Return to initial (starting) Z
G99 → Return to R plane (recommended)
Example:
G99 G73 X40. Y20. Z-12. R2. Q3. F300
Returning to R plane saves time.
7. Multi-Hole Matrix Example (Common in Moldmaking)
G73 X10. Y10. Z-8. R1. Q2. F350
X30. Y10.
X50. Y10.
X10. Y30.
X30. Y30.
X50. Y30.
G80
This is extremely fast for mold cooling-hole patterns.
8. Optimizing Peck Size (Q Value) by Material
Aluminum: Q = 3–6 mm
Brass: Q = 4–10 mm
Mild steel: Q = 1.5–3 mm
Tool steel: Q = 1–2 mm
Stainless: G73 not recommended → use G83
Titanium & Inconel: Never use G73 → use G83 only
9. Common G73 Problems & Solutions
Drill squeals while entering material
– Feed too low → increase F
– Peck too small → increase Q
Chips wrap around tool
– Q too large → reduce peck
– Use G83 instead
Hole oversized
– Worn drill
– Incorrect RPM
– Excess heat due to insufficient pecks
Poor surface finish in hole
– Reduce feed
– Increase peck frequency
– Use rigid holder
10. Example: High-Precision Micro Drilling
For Ø1 mm drill:
G73 X45. Y12. Z-4. R1. Q0.2 F40
Micro-pecks prevent breakage.
11. Summary
G73 is the preferred high-speed drilling cycle for shallow to medium-depth holes where chip control—not deep evacuation—is required. It is significantly faster than G83, making it ideal for production drilling, aluminum parts, and carbide drill operations. When used correctly, G73 improves tool life, reduces cycle times, and enhances machining consistency in modern 2025 CNC environments.
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