Engraving images inside acrylic blocks
You have seen these: a photograph, a logo or a 3D model apparently floating inside a solid clear block, with a surface you can run a finger across and feel nothing. It is a real process, it is not done with the laser on your bench, and the blank it needs is a specific thing.
What we do and do not do
We supply the blank— clear acrylic cut to your size, up to 2″ thick. We do not do the sub-surface engraving itself; that is a specialist machine and a separate service. This page is here so you order the right blank for it.
How the image gets inside
The process is sub-surface laser engraving, and it uses a pulsed green laser at 532nm. The beam is focused not on the surface but to a point inside the block. At that focal point — and only there — the energy density is briefly high enough to fracture the material, leaving a microscopic white dot. Everywhere else the beam passes through harmlessly, which is why the surface stays untouched.
The machine then repeats that thousands of times on a three-dimensional grid, moving the focal point through the block. The dots together read as an image, the same way a halftone does on paper. Nothing is removed and nothing is cut.
Why your CO2 or diode laser cannot do it
Both work at the surface, for opposite reasons. A CO2 laser at 10.6 microns is absorbed by acrylic the instant it lands, so all its energy goes into the first fraction of a millimetre — excellent for cutting, useless for reaching inside. A diode at 450nm has the opposite problem: clear acrylic is transparent to it, so it passes straight through and deposits nothing anywhere.
Pulsing is the other half. A sub-surface engraver fires extremely short bursts whose peak power is enormous while their average power stays low, so the threshold for damage is crossed only at the focal point. A continuous beam would heat everything along its path. Full detail in CO2 vs diode lasers.
What to order for it
Three things matter, in this order:
- Optical quality. Every inclusion, haze or internal stress line sits in the optical path of the finished piece and will be visible through the whole block. This is the one specification you cannot compromise on.
- Thickness. The image needs depth to occupy — commonly 1/2″ through 1″ and up to 2″. Thicker reads as more three-dimensional; thinner reads as a flat image suspended in a sheet.
- Edge finish. A saw-cut edge is fine if the block will be framed or set into a base. If the block is the finished object, a polished edge lets light in cleanly and makes the engraving appear brighter — worth specifying at order time rather than trying to achieve afterwards.
Order clear acrylic cut to size →
FAQ
What laser engraves inside a clear acrylic block?
A pulsed green laser at 532nm. It is focused to a point inside the material rather than on its surface, and each pulse creates a microscopic fracture at that point. Thousands of those points on a 3D grid form the image. A CO2 or diode cutter cannot do this — they work at the surface.
Can a diode or CO2 laser engrave inside acrylic?
No. Both work at the surface. A CO2 laser is absorbed by the acrylic immediately, and a diode laser passes through clear acrylic without being absorbed at all. Sub-surface engraving needs a pulsed source that only deposits enough energy at its focal point.
What thickness acrylic is used for internal engraving?
Thick clear stock — commonly 1/2 inch up to 2 inches. The image needs depth to sit in, so the thicker the blank the more three-dimensional the result. Optical quality matters more than anything else, since every flaw is visible through the whole block.