Laser Cutting and Laser Engraving Acrylic

Polymethyl Methacrylate (PMMA), more commonly known simply as acrylic, sometimes with the trade names of Perspex or Plexiglas, is one of the most popular of all materials to laser cut or laser engrave.

Available in a huge range of colours and finishes, acrylic is easy source, relatively inexpensive and easy to fabricate. It’s no surprise then that acrylic is one of the top plastics used for making signs, point of sale displays and machine guards to name but a few uses of this amazingly versatile material.

Acrylic is manufactured by one of two processes: Cast or Extruded .

Each process produces a material with slightly different physical, chemical and machining properties.

Cast acrylic is by far the best material to use for general applications. It has better scratch resistance and transparency and is available in a wider range of colours and thickness. It has a higher melt point so when laser engraved it will result in a clean, off-white frosted effect similar to that of sand blasted glass.

Extruded acrylic is lower cost and of a more consistent thickness. Its lower melt point provides for an almost polished effect when it is laser engraved, which provides well for processes such as reverse paint filling and it is easier to thermoform into shapes.

In a laser cutter or laser engraving machine shorter wavelength lasers cannot be used for laser cutting or laser engraving acrylic as they pass through the material. Acrylic absorbs the 10.6µm laser wavelength, more commonly known as a CO2 laser. At this wavelength acrylic acts as a waveguide, which allows for a far greater thickness of material to be cut than other materials that do not waveguide, such as wood for example.

When laser cutting acrylic the constant wave (CW) properties of a DC (glass) CO2 laser provides for a superior smooth polished edge.

When laser engraving acrylic the superior beam quality and speed of pulse of the RF (metal) CO2 laser provides for a excellent uniformity of mark and a higher resolution too, especially when laser engraving at high speed.

If the job allows, the protective film should be left on while the acrylic is cut and careful consideration should be given to the type of machine table used because acrylic is easy to damage through backward laser reflection. A table with lamella bars is by far the best to use to minimise this.

Careful attention should be given to the rate of extraction and air assist delivered through the nosecone. Too little and the material may flame, potentially catching fire; too much and the degree of polishing of the edge will be diminished.

At Lotus Laser Systems we manufacture a wide range laser, marking and engraving solutions ideally configured for laser cutting and laser engraving acrylic. Our experts would be happy to recommend which configuration best suits your application.