Falilay Laser Cutting: How Automatic Edge Search Works

• 1
  Falilay laser cutting edge search: what the sensor really measures
• 2
  Why the manual edge find is slow and where it goes wrong
• 3
  Boundary conditions that decide whether the probe succeeds
• 4
  What the function changes in a real nest
• 5
  How the offset reaches the cutting program
• 6
  When to use automatic edge search and when to skip it

The head moves down toward the plate and the nozzle body forms one plate of a capacitor; the sheet is the other. Capacitance rises as the gap closes. The controller watches that curve, stops the descent at a set threshold, and records the Z height. A short move in X or Y repeats the measurement, and the two heights give the local slope of the sheet.

On a Falilay laser cutting machine the routine runs before the cutting program, not during it. The head walks to a teach point near the expected corner, probes in two directions, and passes the corner coordinates to the nesting software. Everything after that is ordinary cutting. The value is not the measurement itself, it is that the measurement happens without an operator watching the gap.

Capacitive sensing is not new. What changed is the speed and the filtering. Older routines needed several seconds per probe and a clean, flat plate. Current controllers sample fast enough to separate the plate signal from the noise of a dusty shop floor, so the probe finishes in well under a second.

The sensor reads distance, not position. It tells the controller where the plate surface is under the nozzle, and the controller converts that into a work offset. If the plate is bowed, the reading is still correct at that point and wrong everywhere else. That distinction matters for the rest of this page.

Manual edge finding means the operator jogs the head until the nozzle sits over the plate corner, then touches off by eye or with a shim. It works, and experienced operators are quick at it. The problem is that it depends on a person being right every time, on every sheet, at the start of every shift.

The errors are small but they compound. A 0.3 mm offset at the corner tilts the whole nest. On a 1,500 mm sheet that is enough to push the last part of the run into the skeleton or off the plate. The operator usually catches it, but catching it means scrapping a sheet and restarting.

There is also a throughput cost that never shows up on a machine spec sheet. Touching off by hand takes 20 to 60 seconds per sheet depending on the operator and the plate condition. On a job that runs 40 sheets a shift, that is most of an hour spent on a step that adds no value to the part.

Fatigue matters more than skill. The first sheet of a shift and the fortieth sheet of a shift do not get the same attention. Automatic edge search does not get tired.

The sensing gap has a practical window. Below roughly 0.5 mm the nozzle is close enough that spatter or a burr on the plate can trigger a false stop. Above 25 mm the capacitance signal gets weak and the controller needs a longer averaging time, which slows the routine and makes it less useful on thin material.

Plate angle is the second limit. The probe assumes the sheet lies close to the machine axis. A tilt of about 3° is the usual working range; beyond that the two probe points no longer describe the local plane well enough to correct the program, and the controller will either reject the measurement or apply a correction that makes things worse.

Surface condition decides more than any setting. Bare aluminium, cold rolled steel and stainless all read cleanly. A heavy oxide layer, mill scale or a thick protective film changes the dielectric behaviour and shifts the trigger point. Plasma-cut edges with dross are the worst case: the corner is not where the drawing says it is.

Nozzle selection matters too. A Ø1.2 mm nozzle gives a tighter sensing field and better repeatability on thin sheet. A Ø2.0 mm nozzle survives thicker plate and rougher handling but spreads the field, which softens the trigger. Pick the nozzle for the job, then let the probe use it.

Fixtures and magnets interfere. If the sheet is held down with magnetic clamps, the field around the nozzle is disturbed and the reading drifts. Non-magnetic hold-down or clamp placement away from the probe path solves it.

The measurable gain is the removal of the manual touch-off and the reduction of sheet-to-sheet offset drift. A probe cycle typically runs in 0.5 to 2 seconds depending on material and thickness. Compare that with 20 to 60 seconds of operator time and the arithmetic is simple.

The second gain is harder to put on a chart but shows up in scrap reports. When the offset is set by the machine at the start of each sheet, a bent or shifted sheet does not silently move the nest. Parts that would have been cut 0.3 mm off-centre get cut on-centre, and the last part on the sheet is as good as the first.

There is a limit to how much this helps. Automatic edge search corrects the work offset; it does not flatten a bowed sheet, and it does not correct thermal growth in the machine over a long run. Those are separate problems with separate fixes.

For a shop running a mix of thin sheet and thick plate, the function pays back fastest on the thin sheet work, where manual touch-off is both slowest and least accurate. On thick plate the time saving is smaller because the operator has to handle the plate anyway.

The probe result is a pair of coordinates and a Z height. The controller writes them into the work offset table, and the nesting software shifts the whole program by that amount. Nothing in the cutting path changes; only the origin moves.

This is why the function is easy to retrofit on a machine that already has a capacitive height sensor. The hardware is the same; the difference is in the controller routine and the way the offset is written back. On older machines the operator may still have to confirm the offset manually.

One detail engineers ask about: the probe does not need to find the exact corner. It needs two points on the plate with a known separation. The controller fits a line or plane through them and derives the corner from that. A dinged corner is not a problem as long as the probe points themselves are clean plate.

For parts that go on to machining, the same origin discipline carries over. If the laser-cut blank is 0.2 mm off, the CNC setup has to absorb it. Holding the blank origin tight at the laser makes the downstream fixture simpler.