LightBurn for Beginners – FAQ & Common Problems

01 Why won't LightBurn connect to my laser? Connection ▼

Most common causes: wrong COM port selected, missing driver, wrong device type in configuration, faulty USB cable, or another program already using the port. Work through this checklist: confirm the laser is powered on and the E-Stop button is released, close LaserGRBL or any other laser software, try a different USB cable, then go to Edit → Devices and manually select the correct COM port.

💡 Open Windows Device Manager (DevMgmt.msc) and check whether the laser appears as a COM port. If it doesn't — you're missing the CH340 or CP2102 driver. Install it, then restart LightBurn.

02 Why does "Find My Laser" find nothing? Connection ▼

Auto-detection only works when the controller properly announces itself to the OS — many machines don't. Instead of waiting for auto-detect, create the device manually: Edit → Devices → Create Manually. Choose GRBL (or the correct controller type) and select the right COM port. Manual setup is faster and more reliable than auto-search in most cases.

💡 Not sure which COM port? In Device Manager, unplug and replug the USB cable and watch which port disappears and reappears — that's your port.

03 LightBurn disconnects in the middle of a job — what should I do? Connection ▼

The most common cause is a poor-quality USB cable or Windows power management cutting the USB port after a period of low activity. Fix it by: using a short shielded USB cable (max 1.5 m), disabling "USB selective suspend" in Windows Power Options, and in Device Manager → COM port Properties → Power Management → unchecking "Allow the computer to turn off this device to save power".

04 The Frame runs in a different spot than where the laser actually burns — why? Positioning ▼

This is caused by a mismatch between the Start From mode and the Job Origin point. Framing shows the area based on the current mode — if it's wrong, the laser will start somewhere else. Check the Laser panel in the bottom-right corner. Absolute Coords is the simplest mode for beginners: your design burns exactly where you placed it on the LightBurn workspace grid.

💡 Stick with Absolute Coords until you understand the differences between modes — it fixes 90% of positioning problems instantly.

05 What is the difference between Absolute Coords, Current Position and User Origin? Positioning ▼

Absolute Coords — the job runs exactly where it sits on the workspace grid. Easiest mode for beginners.

Current Position — the job runs relative to the laser head's current position. The Job Origin dot determines which corner or center of the design aligns with the head.

User Origin — the job runs relative to a saved reference point (set on the machine using the Set User Origin button).

💡 For beginners: use Absolute Coords and place your design on the grid exactly where you want it on the material.

06 My design comes out mirrored or upside down — how do I fix it? Positioning ▼

The culprit is almost always a wrong Device Origin setting — the machine's home corner. Go to Edit → Device Settings and check whether the Origin (bottom-left, top-left, bottom-right, or top-right) matches your machine's actual home position. If your machine homes to the top-left corner after power-on, set Origin to top-left.

💡 Power on the machine, press Home, and watch where the head travels. That corner is your Device Origin.

07 Fill mode doesn't work — letters or shapes are not being filled Fill / Engraving ▼

Fill only works on closed shapes. If a vector has even a tiny gap, LightBurn treats it as open and can't determine the fill area. Select the shape and go to Edit → Auto-Join Selected Shapes (Alt+J) to let LightBurn attempt to close the paths. Also check Edit → Node Editor for disconnected nodes.

💡 Importing an SVG from the internet? They often have "open" paths that look closed. Use Edit → Close Selected Paths after importing.

08 I can't see the fill on the workspace even though the preview looks correct Fill / Engraving ▼

LightBurn displays the workspace in Wireframe mode by default — only outlines, no fill rendering. This is intentional. Always use Preview (Alt+P) to see exactly what will be burned and in what order. The workspace view is for design; Preview is for reality-checking before you hit Start.

09 In what order does LightBurn run Fill and Cut layers? Fill / Engraving ▼

LightBurn runs layers top to bottom in the Cuts / Layers panel. Best practice: engrave first (Fill layer), then cut the outline (Line/Cut layer). If you cut the outline first, the material can shift and your engraving won't land in the right place. Drag layers in the panel to reorder them.

💡 Always cut last — this is the golden rule of laser work.

10 My photo engraving comes out too dark, too light, or just looks bad — how do I fix it? Photos ▼

There is no universal setting — every material and machine is different. Key parameters: Image Mode (use Jarvis, Stucki, or Newsprint for photos on wood), Line Interval (0.1–0.2 mm for good detail), power 15–25%, and speed 2000–4000 mm/min for wood. Always start with a small test piece.

Common mistakes: too much power (burning), using Grayscale mode instead of a dithering mode, Line Interval too large (visible banding).

💡 Use Laser Tools → Material Test in LightBurn — it generates a grid of samples with different power/speed combinations. The fastest path to dialed-in settings.

11 How do I engrave a large image that doesn't fit in the work area? Photos ▼

LightBurn has a Rotary/Tiling feature for oversized projects, but the simplest approach is to split the design manually. Use the Boolean tool or a plain rectangle as a clip mask and export each section separately. For cylindrical engraving (mugs, tumblers) use the Rotary module. For very large flat pieces, check if your machine supports Pass-Through mode.

12 Laser won't cut through the material even at high power — why? Cutting ▼

Most common causes: incorrect focus, dirty lens or protective window, speed too high, not enough Passes. Even 1 mm of focus error dramatically reduces cutting power. Clean the optics with a dry microfibre cloth. Increase Passes to 2–3 instead of cranking power to 100% (which burns out the diode faster).

💡 3 mm plywood: try 90% power, 300 mm/min, 2 Passes. Still not cutting? Focus or dirty optics is the problem — not the power setting.

13 My cut and engraving are offset from each other — how do I fix it? Cutting ▼

The cause is usually Scanning Offset (shift at direction reversals), mechanical backlash, or material moving on the bed. In LightBurn: Edit → Device Settings → Scanning Offset Adjust — calibrate the offset value for each speed you use. Also check that your material is lying flat and not sliding around on the bed.

💡 Scanning Offset is the most common cause of "ghosting" at high engraving speeds. LightBurn has a built-in calibration test — use it.

14 My cut edges are black and charred — how do I get clean cuts? Cutting ▼

Charring happens when power is too high or speed too low. Fixes: enable Air Assist (blows smoke away and cools the cut), increase cutting speed, reduce power and add more Passes instead, check your focus. On plywood you can also apply painter's masking tape to protect the surface from scorching — peel it off after cutting.

💡 Air Assist is one of the best upgrades you can add to a diode laser — noticeably cleaner cuts and much lower fire risk.

15 My imported SVG or DXF file has the wrong size — how do I fix it? File Import ▼

The most common cause is a units or DPI mismatch. For SVG: check whether the file was created at 72 DPI or 96 DPI (Inkscape defaults to 96 DPI). LightBurn asks for the DPI at import — choose the correct value. For DXF: inches vs. millimetres are easy to confuse. Check the scaling options when importing via File → Import.

💡 After importing, select everything (Ctrl+A) and check the dimensions in the toolbar at the top. Compare with the expected size and rescale if needed.

16 Tutorials show different options than what I see — why? File Import ▼

Two reasons: Beginner Mode hides advanced options, or differences based on laser type (GRBL vs. DSP vs. Galvo have different settings). To disable Beginner Mode: Help → Beginner Mode (uncheck). Also check your LightBurn version — from version 2.0 onwards the interface changed and some features moved to new locations.

17 How do I save my settings so I don't have to re-enter them every time? File Import ▼

Use the Material Library (Window → Material Library). You can save your own profiles for specific materials, thicknesses, and operations. When you need them later, just drag a profile onto a layer — done. It's one of LightBurn's most useful features for regular users.

💡 Record every successful material test. A month from now you won't remember that 3 mm plywood ran at 90% power and 300 mm/min.

18 What materials can I cut and engrave with a diode laser? Materials ▼

Yes (engrave and cut): wood, plywood, MDF, natural leather, felt, cardboard, cork, rubber.
Yes (engrave only): stainless steel with Cermark spray, anodised aluminium, ceramic, dark acrylic (cutting is weak).
NO — never: PVC/vinyl (releases toxic chlorine gas), polycarbonate, ABS, chrome-tanned leather, mirrors, tempered glass, any material containing chlorine.

⚠️ Always verify the material composition before lasering. PVC releases chlorine gas that is toxic and damages the laser.

19 Why won't a diode laser cut clear/transparent acrylic? Materials ▼

Diode lasers emit blue light (~450 nm) which passes straight through clear acrylic instead of being absorbed — so the material doesn't heat up at all. Solutions: use coloured or frosted acrylic (darker colours absorb much better), spray the cut line with flat black paint and wash it off afterwards, or switch to a CO2 laser which cuts all acrylic colours including clear.

20 How do I engrave stainless steel with a diode laser? Materials ▼

You need a metal marking spray — Cermark, Thermark, or a cheaper molybdenum disulphide (MoS2) alternative. Apply a thin, even coat to the metal, let it dry completely, engrave at full power and low speed (around 500–1000 mm/min), then wipe the spray off — a permanent black mark remains. Without spray, a diode laser will only scratch the surface.

21 Should I run Preview before every job? General ▼

Yes — make it a habit. Preview (Alt+P) shows the actual laser path, the order of operations, job duration, and any problems with fill, position, or out-of-bounds moves. Many errors — especially with Fill layers and positioning — are visible in Preview before you waste material. It takes five seconds and saves real money.

22 I changed settings and now my laser has lost power — how do I reset? General ▼

LightBurn has no single "Restore Defaults" button, but try these steps: 1) Edit → Device Settings — reset Max Speed and Acceleration to the values from your laser's documentation. 2) Check whether the S key is toggled on (test mode — no burning). 3) In the Cuts / Layers panel, check that layer Power isn't accidentally set to 0–5%. 4) Try Help → Restore Factory Settings if available in your version.

23 How do I make LightBurn always cut the outline last? General ▼

In the Cuts / Layers panel, drag the cut layer (Line) to the bottom of the list — LightBurn runs layers top to bottom. If you have a Fill layer and a Line/Cut layer, Fill should be above, Line/Cut below. You can also fine-tune this in Optimization Settings (the button next to Start).

24 How much does LightBurn cost and is there a free trial? General ▼

LightBurn costs $60 for diode and GRBL lasers or $80 for DSP/Ruida (CO2). It's a one-time purchase with lifetime access and one year of free updates. There is a 30-day free trial with full functionality — just download from lightburnsoftware.com and install without entering a key.

💡 Given what materials and machines cost, $60 for LightBurn is one of the best purchases you can make in laser work.

25 How do I run a Material Test in LightBurn? General ▼

Go to Laser Tools → Material Test. Set the power range (e.g. 10–90%), speed range (e.g. 500–3000 mm/min), and the number of columns and rows. LightBurn generates a grid of labelled rectangles — each one shows its power and speed values. Run it on a scrap of your target material, pick the best-looking square, and those are your optimal settings.

💡 Run a Material Test for EVERY new material. It takes a few minutes and saves a lot of wasted stock in the long run.