Laser Cut Quality Inspection

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Inspection and evaluation of laser cut quality is a prerequisite for quality control. The operator can verify cut quality through the following parameters.

Piercing quality

At the start of laser cutting, a small hole must be pierced through the workpiece surface before linear cutting motion begins. This piercing process is one of the most important checks for correct laser cutting parameters.

If the pierce shows unusual sparks, abnormal noise, an oversized hole / gap, or molten metal splashing at any stage of the pierce, the cutting parameters are wrong. This leads to nozzle overheating and protective lens damage.

Finished part dimensions

Most laser-cut parts are components for assembled structures, so the finished dimensions must be accurate for trouble-free assembly.

Before starting full production, cut a small test sample — a square with a hole.
Measure the hole and the square with a caliper; confirm dimensions meet specification and stay within tolerance.
If dimensions are off, apply kerf compensation for inner and outer contours.
Verify that the cut result matches the programmed cutting path — for example, that dimensions do not drift when using common cuts.
If settings are wrong (e.g., lead-in) or the nozzle is damaged, the hole will not come out perfectly round.
Use loops and cooling points when needed to preserve sharp corners.

Kerf width

The kerf (cutting slot) in laser cutting is formed by partial melting of the metal under the laser beam. Kerf width directly reflects cut quality. An oversized kerf means laser power is too high or cutting speed is too low, causing excessive melting of the metal.

Edge roughness

Edge roughness can be assessed by the depth of the vertical lines (striations) on the cut surface.

Sharp, deep vertical lines — high roughness, poor cut quality.
Very fine vertical lines — low roughness, good cut quality.

Taper and corner rounding

Taper is the angle between the top and bottom of the laser kerf.

With correctly set parameters, taper is extremely small and can be ignored.
On thicker workpieces, the laser focus position gradually shifts and the beam diverges, widening the kerf and producing a noticeable taper.
Taper is corrected primarily through parameter tuning; nozzle wear is also a common cause.
Corner rounding is mostly caused by nozzle deformation or by worn / misaligned moving parts of the machine.

Burrs and dross

Burrs and dross directly reflect laser cut quality and are a common issue when cutting various metals.

A correctly tuned laser cutting process produces almost no burrs.
If burrs appear on the cut edge, the cutting parameters are wrong.
Burr problems differ by metal; most are eliminated by setting the correct cutting parameters.

Deformation

Deformation is a frequent issue in metalworking. It typically occurs when cutting thin sheets or processing small, delicate parts.

If laser cutting parameters are wrong and the heat input from the laser beam is too high, this affects the material and causes thermal deformation. Overheating and deformation must be prevented by controlling laser power, feed rate, and other cutting parameters.

HAZ (Heat-Affected Zone)

A laser cutting machine produces the cut by melting or vaporizing the material. The material surrounding the kerf is also heated by the laser, which alters its molecular structure. The region where the molecular structure has been changed by laser irradiation is called the HAZ (Heat-Affected Zone).

Laser cutting inevitably produces a HAZ, but with the right measures its extent can be kept within acceptable limits.

Quality of the base metal

Unfortunately, today's market reality is that metal producers seek to maximize cost savings in production, lowering the price of the finished product at the expense of quality. The operator must be prepared for this and treat each batch of metal carefully:

Always prepare the metal — clean off rust and contamination.
First tune parameters on a test sample, then run production cutting of the actual parts.