Laser-Cut vs Router-Cut Acrylic Edges

Short answer: A laser-cut acrylic edge comes off glossy and finished but carries a stressed zone about 0.010 to 0.050 in. deep and tapers slightly on thick sheet. A router-cut edge is square and satin with fine tool marks, has far less heat stress, and is the best starting point for solvent bonding and for flame or diamond polishing. Choose laser for detail and finished-looking edges up to 1/2 in.; choose routing for thick sheet, bonded cases, and parts that will meet solvents or cleaners.

Side by side

	Laser-cut edge	Router-cut edge
Look	Glossy and clear, close to flame polishing	Satin or matte, frosted look
Feel	Smooth; faint vertical lines on thick sheet	Smooth with faint tool marks; crisp square corners
Squareness	Slight taper on thick sheet	Square to the face
Internal stress	Higher: a stressed zone about 0.010 to 0.050 in. deep	Lower, if the bit is sharp and the feed steady
Inside corners	Sharp	Radius equal to the bit's radius
Best for bonding	Light-duty, after annealing	Yes: flat, square, low stress
Thickness	Up to 1/2 in. with us	Any, including 3/4 and 1 in.
Typical tolerance	About ±0.005 in.	About ±0.010 in.

What is a laser-cut acrylic edge like?

A CO2 laser's 10.6 µm light is absorbed strongly by acrylic and vaporizes a narrow channel. The walls of that channel melt for a moment and set glossy, so the edge needs no polishing. On 1/8 and 1/4 in. sheet it looks almost like glass. Both cast and extruded sheet come off glossy; laser makers such as Epilog note that extruded gives the most flame-polished look.

On 3/8 and 1/2 in. you'll see faint vertical lines (striations) if you look closely, and a slight taper: the cut is a little wider where the beam enters than where it exits. Cutting in a single pass matters here. Trotec notes that each extra pass leaves visible lines on the edge.

The fast heating and cooling also locks stress into the edge. Acrylite measures that highly stressed zone at about 0.010 to 0.050 in. deep, depending on thickness, and says it crazes easily if it meets incompatible solvents or is bent. More power gives a glossier edge but more stress. That's why Acrylite recommends annealing after laser cutting and why Trinseo says not to flow solvent cement onto laser-cut surfaces. More in why laser-cut acrylic cracks later.

What is a router-cut acrylic edge like?

A CNC router cuts with a spinning carbide bit. Trinseo's Plexiglas guide calls routing the method that gives the best overall fabricated edge, and gives the conditions: sharp two-flute (or spiral-flute for thick sheet) cutters, about 10,000 to 20,000 rpm, and a smooth, steady feed of 10 to 25 ft/min, because a stalled or slow feed heats the plastic and smears or gums the edge.

Done right, the edge is smooth to the touch with a satin, slightly frosted look and fine tool lines along its length. It's square to the faces even on 1 in. sheet. Because the bit is round, inside corners have a radius equal to the bit's radius, often 1/16 to 1/8 in.

A routed edge is the standard starting point for the other edge finishes. Acrylite notes that a well-machined edge can be buffed without sanding first, and that machine-finished edges are ideal for cementing or flame polishing. Diamond polishing a routed straight edge gives a crisp, glass-clear square edge, and Perspex notes it adds very little stress. See our edge polishing options and how to polish acrylic edges.

Which edge is better for gluing acrylic?

Routed edges are square and flat, so the joint closes evenly and capillary cement such as Weld-On 3 or Weld-On 4 wicks in cleanly. For display cases, aquariums, and anything that must look perfect or hold water, a machined edge is the better choice. Don't polish edges you'll bond: Plaskolite and Trinseo both note polishing rounds the corners and reduces the contact area.
Laser edges bond fine for many boxes and light-duty assemblies, especially in cast sheet. The risk is crazing where solvent meets the stressed edge, plus a thin gap along one side of the joint on thicker sheet because of the taper. Annealing the parts first, or scraping off the stressed layer, reduces the crazing risk.

Don't flame polish an edge you plan to bond: it adds stress and rounds the edge. Bond first, then polish exposed edges if needed. More in how to glue acrylic.

When should you choose each?

Choose a laser-cut edge for

Signs, letters, awards, ornaments, cake toppers, and anything where the edge shows and should look finished.
Intricate shapes, small holes, and sharp inside corners.
Tab-and-slot boxes and enclosures in 1/8 to 1/4 in. sheet (tab-and-slot design).
Edge-lit panels, where the glossy edge lets LED light in cleanly.

Choose a routed edge for

Sheet thicker than 1/2 in. (thick acrylic cutting).
Solvent-bonded cases where joints must be clear and strong.
Parts that will be cleaned with alcohol or disinfectants, painted at the edge, flexed, or bolted tightly.
Edges you want satin, or flame or diamond polished after.

If you're unsure, put the use in your order notes and we'll choose. You can get an instant quote with either finish.

Questions

Can I make a laser edge look like a routed edge?

Yes. Sanding or scraping a laser edge gives it a satin look and removes the outer, most stressed layer at the same time. Acrylite suggests wet sanding edges with 180 to 320 grit for a satin finish.

Is laser taper a problem on 1/4 in. acrylic?

Rarely. On 1/4 in. and thinner the taper is very small. It matters mostly on 3/8 and 1/2 in. sheet where parts must fit tightly or bond edge to face.

Is one edge stronger than the other?

For normal loads both are fine. A smooth laser edge has fewer tiny nicks to start a crack, but its locked-in stress makes it more sensitive to chemicals and bending. A routed edge is less chemically sensitive.

Is a laser edge the same as a flame-polished edge?

They look alike and both are made by melting the surface, and both carry stress. A flame-polished edge starts as a routed or sawn edge and is usually a little more rounded; Acrylite recommends annealing after flame polishing too.

Laser-cut vs router-cut acrylic edges