The Laser Loop Lead Extension is a Leadin Extension shaped as a closed loop, so that the cut crosses its own kerf before reaching the part boundary.
When cutting thick stainless steel with a laser, the cut face can be irregular near the start of the cut while the process settles. It has been observed that having the cut cross its own kerf can sometimes stabilise that irregular cut face — the second pass through the kerf interacts with the edge left by the first pass and helps even it out. The laser loop lead extension is designed to provide that kerf crossing deterministically, as part of the leadin, so the part boundary itself is reached with a stable cut.
A laser loop lead extension. The cut runs through the loop and crosses its own kerf before reaching the part boundary.
When to use it
Consider a laser loop lead extension when:
•Fusion Cutting thick metal with a laser.
•The cut face quality at the start of the part boundary is inconsistent or rough.
•A plain line or arc leadin is not delivering a stable enough start to the boundary cut.
•An "edge start" seems to start the cut with a cleaner cut face.
Upper part cut with standard pierce, develops rough bead around midline, below which striations are more irregular and cut has more dross. Edge starting avoided this, as did use of the laser loop lead extension after piercing, as in the lower part (20mm SS cut with N2)
This is an empirical technique. The benefit depends on material, thickness, assist gas, and beam parameters, so confirm on a test coupon before committing to a production sheet.
Adding a Laser Loop Lead Extension
A laser loop is added as a Leadin Extension on an existing leadin segment. The general lead-extension workflow — selecting the leadin, setting the Leadin Extension property, and dragging the handles to size the loop — is the same as for other extension segments. See Thermal Lock Leadins and Leadin Chaining for the general extension mechanics, and Leads for an overview of leads.