The short answer
A material test grid is a small matrix of squares, each engraved at a different speed and power. You vary speed along one axis and power along the other, run it on a scrap of your material, then pick the square that looks best. It takes a few minutes and gives you settings that genuinely fit your laser — far more reliable than copying numbers. Save the winning combination so you never have to guess for that material again.
A grid of squares at different speed/power
Run it on a scrap of your real material
Pick the best square; save those settings
What a test grid is
Think of a simple table. Each column uses a different speed, each row a different power, and each cell is a small filled square engraved with that combination. After it runs, you can see at a glance which combinations are too light, too burned, or just right. The same idea works for cutting, using passes and power instead.
Columns = speed, rows = power
Each cell engraved with that combination
Reveals too-light, too-burned and just-right
How to set one up
Pick a sensible range for your laser — for engraving, a spread of speeds and a spread of power percentages — and keep the line interval fixed so only speed and power change. Use a small square per cell with a little gap between them, label the axes, and run it on a flat offcut of the exact material you will produce on. Keep the focus and lens the same as your real job.
Fix the interval; vary only speed and power
Small labelled squares with gaps
Use the real material, focus and lens
How to read the results
Look for the cell with the cleanest mark or cut: dark and crisp for engraving, fully separated with the least scorching for cutting. Note the speed and power for that cell. If everything is too dark, raise speed or lower power; if too faint, do the opposite. Re-run a tighter grid around the best cell if you want to fine-tune.
Cleanest, crispest cell wins
Too dark → faster or less power
Re-run a tighter grid to fine-tune
Save the winner as a recipe
Once you have the right cell, save those values so you never repeat the test for that material. In Vextrify a recipe stores material, tones, dithering and machine settings together, so the next job on that material starts from a known-good state. You keep the test-grid discipline, but only do it once per material.
Record speed, power and interval
Save it all as a reusable Vextrify recipe
Test once per material, reuse forever