How to engrave acrylic with laser

Acrylic materials are widely used. They are cheap and have good laser absorption. They can be used to make various products, including various signs, gifts and prizes.

Most people usually choose transparent acrylic because it is popular and easy to use. This kind of transparent acrylic is generally engraved with carbon dioxide laser, which is determined based on the characteristics of light. The wavelength of carbon dioxide laser is 9.2-10.8μm, and carbon dioxide laser can also be called molecular laser.

To use laser engraving acrylic material, we must first understand the general classification of the material. Acrylic refers to thermal plastics manufactured by various brands. Acrylic panels are divided into two categories: cast panels and extruded panels according to the production process.

Acrylic cast sheet: high molecular weight, excellent stiffness, strength and excellent chemical resistance. This kind of board is characterized by small batch processing, incomparable flexibility in color system and surface texture effect, and complete product specifications, suitable for various special purposes. (When laser engraving, cast acrylic will be transformed into a cold material that is pursued in many custom applications. It can be molded into different shapes and sizes, and due to its good optical quality, it is often used to make awards.)

Acrylic extruded sheet: Compared with cast sheet, extruded sheet has lower molecular weight and weaker mechanical properties. However, this feature is conducive to bending and thermoforming processing, and is conducive to rapid plastic vacuum forming when processing large-sized plates. At the same time, the thickness tolerance of the extruded plate is smaller than that of the cast plate.

It is easier to manufacture extruded acrylic than cast acrylic, which makes extruded acrylic cheaper. In addition, the extruded acrylic is clean and smooth after laser engraving, and the edges are flame polished. The laser engraved product looks very clear, not like the frosted appearance after casting acrylic engraving. It is also softer in comparison and tends to stick during the rotating engraving process.

Laser engraved acrylic works best at low power and high speed. If your acrylic material has coating or other additives, please increase the power by 10%, but keep the speed of using on unpainted acrylic. This provides more energy for the laser to cut paint. The material in question will determine the ideal frequency setting for your laser. However, if you use cast acrylic, you can engrave at high frequencies of 10,000 – 20,000 Hz, and if you use extruded acrylic, you may want to engrave at a lower frequency of 2,000 – 5,000 Hz. A lower frequency will result in a low pulse, thereby increasing the pulse energy or reducing the constant energy in the acrylic. This phenomenon results in less boiling, less flame and slower cutting speed.