Fiber-Laser Sheet Cutting, Nesting Cycle-Time Quoting & CNC Kerf Compensation
Fiber-Laser Cutting Pierce Time, Kerf & Cycle Time Formula
Calculate Total Pierce Dwell Time (s), Contour Cutting Time (s), Total Part Cycle Time Including Rapid Moves (s), Gross Parts Per Hour, and CNC Toolpath Kerf Offset (mm).
On perforated plates, oxygen/nitrogen pierce dwell time often rivals actual laser cutting time!
Quoting CNC fiber-laser sheet-metal parts solely from Cut Perimeter L_cut (mm) divided by Linear Cutting Feed V_cut (m/min) severely underbids multi-hole brackets! Every internal bolt hole and outer contour requires an initial stationary/ramped Pierce Dwell t_pierce (s, ~0.2–0.5 s in thin nitrogen-cut sheet vs 1.5–4.0 s pulse-piercing thick mild-steel plate with oxygen!) plus head-up Rapid Positioning Moves L_rapid (mm) at gantry speed V_rapid (m/min): Total Part Cycle Time t_part = N_pierce * t_pierce + (L_cut / (V_cut * 1,000)) * 60 + (L_rapid / (V_rapid * 1,000)) * 60 seconds! Simultaneously, because the focused laser vaporizes/melts a slot of full Kerf Width w_kerf (mm), the CAM post-processor offsets the beam centerline by Half-Kerf G41/G42 = w_kerf / 2 OUTWARD on external part perimeters and INWARD on internal holes so finished steel hits print tolerance!
Verify on a 12-Hole Stainless Chassis Bracket—Total_Cut_Perimeter L_cut = 1,840.0 mm (B2), Contour_Pierce_Count N_p = 12 (B3), Pierce_Dwell_Time t_p = 0.45 s (B4 -> Total Pierce Time = 5.40 s in E2), Cutting_Feed V_cut = 4.80 m/min (B5 -> Contour Cut Time = 23.00 s in E3), Rapid_Travel L_rap = 600.0 mm at 60.0 m/min (B6, B7 -> 0.60 s), and Laser_Kerf_Width = 0.22 mm (B8): Total Cycle Time hits 29.00 seconds/part (E4, 124.1 parts/hr) with Half-Kerf Beam Offset = 0.110 mm (E5)!
| Fiber-Laser Quoting KPI (1,840 mm Cut, 12 Pierces @ 0.45 s, 4.8 m/min, Kerf=0.22) | Formula | Verified Output |
|---|---|---|
| Total Pierce Dwell Time (sec) | Pierce_Count * Pierce_Dwell_sec | 5.40 s (21.60 s @ 1.80 s thick plate!) |
| Contour Cutting Time (sec) | (Cut_Perim_mm / (Cut_Feed_m_min*1000))*60 | 23.00 s (69.00 s @ 1.60 m/min plate) |
| Total Part Cycle Time (sec) | Pierce_s + Cut_s + Rapid_Move_s | 29.00 s (91.20 s @ thick plate) |
| CNC Half-Kerf Beam Offset (mm) | Laser_Kerf_Width_mm / 2 | 0.110 mm (0.180 mm @ 0.36 mm kerf) |
CNC Fiber-Laser Cycle Time & Half-Kerf G41/G42 Offset Formula
Validate Cut_Perimeter > 0, Pierce_Count >= 1, Pierce_Time >= 0, Cut_Feed > 0, Rapid_Dist >= 0, Rapid_Speed > Cut_Feed, and Kerf_Width in (0, 2.0] mm!
=LET(lc_m, B2, np_c, B3, tp_s, B4, vc_m, B5, lr_m, B6, vr_m, B7, kw_m, B8, IF(OR(lc_m <= 0, np_c < 1, tp_s < 0, vc_m <= 0, lr_m < 0, vr_m <= vc_m, kw_m <= 0, kw_m > 2), "Invalid Laser Input", ROUND(kw_m / 2, 3)))Thick Oxygen-Cut Carbon-Steel Plate Pulse-Pierce Check (Set t_pierce = 1.80 s, V_cut = 1.60 m/min, Kerf = 0.36 mm)
Step up to thick oxygen-cut carbon-steel plate (set B4 = 1.80 s, B5 = 1.60 m/min, B8 = 0.36 mm): Pierce Dwell E2 quadruples to 21.60 s, Contour Cut Time E3 triples to 69.00 s, Total Part Cycle Time E4 climbs from 29.00 s to 91.20 s, and Half-Kerf Offset E5 widens to 0.180 mm!
=IF(ISTEXT(E5), E5, ROUND(B3 * B4 + (B2 / (B5 * 1000)) * 60 + (B6 / (B7 * 1000)) * 60, 2))Try the example
Use the original values or change them to test your understanding.