The Acrylic Laser Cutting Process Explained

Acrylic Laser cutting has become increasingly popular in industrial applications because of the need for precision ad edge quality. It comes with a myriad of benefits, including reduced through put, sustainable cost, increased productivity and minimum waste. Here is what you should know about the process of laser cutting.

What to Expect In a Laser Cutting Process

Several factors that should be considered before you start the laser cutting process. The main questions most people as are ‘what do I expect out of the end of the process? Do I need the final product to be perfectly flame polished or is the product meant for mechanical use in which edge quality is not critical? These questions will help you determine the kind of final cut that you will produce. Here are some of the factors that will influence your laser cutting process:

• Materials used i.e. the brand and the type of Acrylic
• Laser Parameters used
• Power
• Speed
• Frequency
• Table Setup
• Laser Process Setup
• Lenses and Focus
• Exhaust
• Gas

Preparation of the Materials

When all these variables are well managed, you will have perfect, repeatable laser cuts from your acrylic materials. The materials should be prepared with a lot of care to ensure that you do not interfere with the accuracy and precision of the final product.

Laser Physics (Technology)

The technology behind obtaining a fine laser cut using acrylic is a bit complex and daunting. Fortunately, you can understand the process by checking the important change processes that the materials go through from the beginning to the end. Here is a summary of the phase changes to expect:

The cutting of acrylics is done by vaporising the solid acrylic material. The material absorbs the laser, making it to change from solid to liquid and finally to vapour. The entire process of this material change is done with minimum chemical degradation. To reduce the significant amount of vapour released during the laser cutting process, a vacuum system is used. Do not leave the laser system unattended, as the vapour emitted is chemically active and flammable and may cause fires if not well attended.

Nitrogen gas is used to blow the vapour away from the cutting surface, to help prevent any ignitions. The gentle stream of nitrogen gas also helps to change the liquid along the cut line. This helps to create a glossy, smooth flame-polished finish. But nitrogen has its own downsides, especially because it is too powerful that it can disrupt the cutting edge during the process of solidification, hence creating a wavy or frosted cutting edge. However, you can manage this situation by using a variable pressure regulator.

Types of Acrylic

Two common types of acrylic exist, cast and extruded acrylic. Both are manufactured differently and hence have varied cutting characteristics. Cast acrylic is perhaps the best, which is why it is applicable in most applications. However, under unique circumstances, extruded acrylic may be desired over cast acrylic.

The power usage is extremely important when determining the quality of the outcome in laser cutting. It is agreed that every 10 watts of power should cut 1mm or 0.004 inches of acrylic material, a rule that allows you to flame polish your laser cuts at a fairly good speed. However, this doesn’t mean that you cannot achieve a 12mm /0.5 inch using 60watts. But the quality of the final cut won’t be near perfect and the process will be a little slower. In general, more power allows you to achieve high cutting speed and gives you better quality cuts on both thin and thick materials. As a rule of thumb, peak power is the trick for achieving top-notch laser cuts.

No quality outcome is guaranteed without quality exhaust. It serves two important purposes. First, it helps to prevent flaming of the acrylic material. The exhaust system is used to transfer excess gases and vapour away from the cutting area, hence avoiding the materials to ignite because of their flammable nature. Secondly, the exhaust system helps to control the solidification of the acrylic that is in liquid state. The flow of a stream of air through the kerf of the cut allows the acrylic material to melt completely, giving you the much needed polished cut and avoid a wavy edge in your acrylic Laser cutting process.