Laser Cutting & EngravingDialing In SettingsGalvo timing & delays

Tune Start TC and Laser Off TC on a galvo laser

On a galvo (fiber/UV) laser, speed and power aren’t the whole story. Timing delays decide whether your hatch lines meet the contour cleanly or leave gaps and burn-in — and they’re tuned on a test card, not guessed.

⚡ Rule of thumb

Set jump delays to a safe baseline, then tune Start TC and Laser Off TC on a hatched-square test card until the fill lines just meet the contour with no gap and no burn-in.

Starting point

Jump delay 500/500/500 baseline · tune TC on a hatched square

Measured

Start TC / Laser Off TC in microseconds, read on a test card

Confidence

Process-dependent

▶ Source video — The COMPLETE Guide to Timing and Delay for Galvo Lasers — Laser Everythingwatch on YouTube ↗

Applies to

Process: Galvo lasers — fiber, UV, CO₂ galvo
Software: EZCAD 2 / EZCAD 3 / LightBurn for galvo
Settings: Start TC, Laser Off TC, polygon, jump delay

Why it matters

A galvo fires the laser while steering mirrors accelerate and stop. If Start TC is too long the mirrors move before the beam fires and you get a gap at the start of each line; too short and the beam burns a hole before the mirrors move. Laser Off TC is the mirror image at the end of the stroke. These delays are what make a hatch fill actually reach the contour.

You can’t eyeball these from software defaults — you tune them. And jump delay has to be pinned first: if it’s off, it skews how you read the timing, so start it slow and safe (500/500/500) and set it aside before touching the TC values.

What good looks like

Hatch fill lines meet the contour cleanly — no gap, no bulge, no scorched intersection
Timing was found on a labelled test card and inspected (a cheap USB microscope helps)
Jump delay is set to a safe baseline before Start/Laser Off TC are tuned

How to apply it

Set jump delay to a safe baseline (≈ 500/500/500) and leave it alone for now.
Zero the timing values (leave polygon/NTC at ~100) to get a constant starting point.
Mark a small hatched square (e.g. 20×8 mm, 2 mm line spacing) stepping Start TC from +1000 to −1000 on a fine-detail material (a metal card works well).
Pick the value where lines just close the gap without burning; repeat the card for Laser Off TC, then split the difference between the best two if needed.

Exceptions & tradeoffs

Only marking-quality matters and speed doesn’t? You can leave jump delay at the slow safe baseline and skip that part of the tuning.

Common mistakes

Tuning Start/Laser Off TC before pinning jump delaySet jump delay to a safe baseline first — it skews the timing read otherwise
Trusting the EZCAD tooltip that Start TC delays the mirrorsIt delays the laser, not the mirrors — read the card, not the tooltip

Laser EverythingSource & visual reference

Start TC / Laser Off TC behaviour, the jump-delay baseline, and tuning timing on a hatched test card — The COMPLETE Guide to Timing and Delay for Galvo Lasers ↗.

Summarized and independently edited by Start Here. Starting values and cautions are our editorial notes, not a quotation from the creator.