Free Material Test Grid Generator for Diode Lasers

What is a material test grid?

A material test grid (sometimes called a "speed/power matrix" or "burn matrix") burns a grid of small squares onto a scrap piece of your target material. Each row uses a different speed — slowest at the top, fastest at the bottom. Each column uses a different power — lowest on the left, highest on the right. After burning, you can compare all combinations side by side and find the setting that gives you the result you want: cleanest engrave, deepest cut, or sharpest contrast.

This is the fastest calibration method for any new material, new machine, or changed material batch. It eliminates the guesswork of "try one setting, see if it worked, adjust, repeat." One 10-minute burn tells you everything about a 20-setting range.

How to use the SVG output in LightBurn

The SVG download is the easiest workflow for LightBurn users. It imports a labeled grid that you assign laser settings to in the Cuts/Layers panel.

1. Download the SVG file and save it somewhere you can find it.
2. In LightBurn: File → Import and select your SVG. The grid appears on the canvas at the correct physical size (in mm).
3. Select all objects (Ctrl+A) and assign them to your desired layer. Set the layer to "Line" (cut) mode — this traces the square outlines and shows you burn depth and edge quality.
4. To test different speeds per row, select each row's cells and assign a different layer color. Then in the Cuts/Layers panel set the Speed for each layer to match the row's labeled value.
5. Position the grid on your scrap material in the workspace. Run Frame first to confirm it fits.
6. Run the job. After burning, read the axis labels: power on top, speed on the left. The cell where both axes look right is your new baseline setting.

How to use the G-code output (LaserGRBL / direct GRBL)

The G-code file is fully automated: it burns every cell at its pre-assigned speed and power, in order, without any additional software setup. Every cell is a single square outline — the laser traces the perimeter at the given settings so you can compare burn depth and edge quality across the grid.

1. Open your GRBL control software (LaserGRBL, Candle, OpenBuilds Control, etc.).
2. Connect to your machine and open the GRBL console. Send $32=1 and press Enter to enable laser mode. Without this, the laser will fire during rapid moves — which is dangerous.
3. Manually jog the laser head to the front-left corner of your test material. Set this as work origin: send G92 X0 Y0 (or use your software's "Set Origin" button).
4. Load the .nc file into your software. Run a dry framing pass first (no laser — in LaserGRBL use "Run Border") to confirm the grid fits within your material.
5. Confirm focus is correctly set for your material thickness.
6. Run the file. Total burn time varies — a 5 × 4 grid at typical engraving speeds takes 5–15 minutes.

M4 dynamic power vs M3 constant power

The G-code mode selector controls how GRBL handles power during acceleration and deceleration:

• M4 (dynamic, recommended): Laser power scales proportionally with actual machine speed. At the start of a move when the machine is still accelerating, the laser runs at reduced power. At full speed, it runs at the programmed power. This prevents dark spots and corner burns that happen when the laser dwells at full power during slow acceleration. Use this for most engraving work.
• M3 (constant): Laser runs at the full programmed power regardless of machine speed. Use this when you need consistent power throughout a move — for example, when applying marking spray to metal, where surface chemistry rather than heat depth drives the result. Corners will be slightly darker.

Reading your test grid results

After burning, examine the grid in good light — angle the material to see depth variation:

• For engraving: Find the cell with the cleanest, most even mark at the contrast level you want. Too light (increase power or slow down), too dark or charred (reduce power or speed up), rough edges (try higher speed with more power).
• For cutting: Check which cells cut all the way through. The fastest speed that still cuts cleanly is your target — it minimizes heat and char. For materials thicker than the laser can cut in one pass, run multiple passes; this single-pass test shows you the deepest single-pass achievable.
• Read the axis labels: Power percentage on top, speed (mm/min and mm/s) on the left. Each cell is labeled with both values in the corner of the square.

Safety reminder

See also

• Basswood plywood cutting settings (5W–40W) — use the test grid to dial in for your specific machine and thickness
• Leather engraving settings — including safety notes on chrome-tanned leather
• Acrylic cutting settings — why color matters and what a diode laser can actually cut
• Anodized aluminum engraving — why less power is usually more
• Laser safety reference — materials you should never laser and why
• LaserGRBL vs LightBurn comparison — which software to use for the SVG vs G-code workflows
• How settings are sourced — our sourcing model and wattage normalization method