Direct Answer
A CNC drill line feeds structural steel sections through a machine that uses the DSTV/NC1 file from the detailer to automatically position and drill all bolt holes, burn or saw copes, and engrave piece marks — all in a single pass. Modern drill lines (e.g., Peddinghaus, Ficep, Voortman) process a W-shape beam in 4–8 minutes versus 2–4 hours for manual layout and drilling.
Full Explanation
The workflow: (1) NC1 file is loaded into the machine's CNC controller. (2) The raw section is placed on the infeed conveyor. (3) The machine auto-measures the section profile to verify it matches the expected section. (4) The section advances to the drill head, which positions and drills each hole per the NC1 file — multiple spindles drill simultaneously. (5) The section advances to the scribing head, which marks the piece mark, heat number, and any assembly marks. (6) The section exits to the outfeed conveyor and is staged for the next operation (welding, coating).
What This Means for Your Shop
CNC drill lines require upfront investment in software integration — your Tekla model must produce clean NC1 files that your specific machine version can read. The setup investment pays back quickly on projects with more than 50 members.
Common Mistakes
Not verifying NC1 files against approved shop drawings before running the first member. If there's an error in the Tekla model, the drill line will faithfully reproduce that error across the entire run.
Recommended Process
Implement a 'dry-run' verification: before running the first member, display the NC1 file in the machine's preview mode and compare hole locations to the shop drawing by eye. Run the first member, measure all holes, and sign off before continuing the batch.