Acrylic (PMMA, acrylic glass) is an interesting material that is widely used for creating different products. It is quite expensive and, therefore, requires proper machining.
Today we are going to find out how to cut acrylic on a laser machine. If you are new to this business, this will help you to avoid mistakes when machining this material with a laser.
What acrylic glass to select for laser cutting and engraving?
There are two types of acrylic: casted and extruded. Casted acrylic is more suitable for laser cutting.
Extruded acrylic is rarely cut by the laser because it is more prone to cracking than the casted one. This is due to the creation of post-stressing, which can lead to cracking when exposed to the heat of the laser beam.
Lower than that of casting acrylic divergence is one of the advantages of extruded acrylic glass. However due to the higher risk of cracking, it is not recommended to choose it for laser treatment. Casted acrylic is more suitable.
Exhaust system: how to avoid a fire
When cutting acrylic, it is necessary to use a properly working exhaust system. The reason is that when there is no exhaust system, the risk of the material catching fire is very high. In addition, when cutting acrylic glass, a workshop can be filled with gasses that are prone to flame up or even explode. It is dangerous.
That is why it is important to monitor the machine. It is not recommended to leave working equipment unattended or leave the room when cutting acrylic. There has been an unpleasant incident with one of the Wattsan customers when a machine operator went out for a smoke while another employee entered and accidentally touched an air compressor hose without noticing this. The exhaust system stopped working, and soon a machine was on fire. Luckily, the fire was put out.
How dangerous is the machining of acrylic glass on a CO2 laser machine?
Health hazards to an operator occur if the exhaust does not work for some reason. Or in case when acryl is being processed with an open machine lid.
For this reason, it is necessary to check the exhaust system operation, air a workshop, and cut acrylic with a closed lid.
Features of cutting acrylic with a laser
When choosing a CO2 laser machine, it is recommended to consider the thickness of the acrylic glass to be processed. This determines the power of a laser tube.
The cutting speed parameters for acrylic should be set up manually. Also, it is important to reduce blowing to a minimum. If you work with the same blowing pressure as when processing plywood, the resulting cut will be of a poor quality. The top edge will be rough.
A simple trick can be used when selecting the blowing pressure in order to get a mirror-like cut edge. Blow on your finger with all your strength; remember the sensation on your skin. Then, set up the same pressure on your machine, checking it with your finger. You can choose slightly stronger blowing, but not weaker, otherwise there will be much soot, and the machine will fail very soon.
To perform laser engraving or cutting of acrylic, it is recommended to set the power of the machine to the lowest possible level. To do this, you can use a potentiometer.
Top laser machines for machining acrylic
The Wattsan 0203 micro
| Work area | 200 x 300 mm |
| Tube power | 40W |
| Max engraving speed | 700 mm |
| Dimensions | 810 mm * 500 mm * 265 mm |
A laser machine for engraving on acrylic. A 40 W laser tube allows you to engrave and cut acrylic up to 6 mm thick. Among the machine’s advantages, there is a durable steel profile gantry and quite small dimensions – 810x500x260 mm. It can be placed on a usual table and is often used for hobby or small-scale production. The working area size is 20×30 cm.
The Wattsan 0503
| Work area | 500 x 300 mm |
| Tube power | 60W |
| Max engraving speed | 700 mm |
| Dimensions | 650 mm * 1040 mm * 575 mm |
A medium-format laser machine that is designed for cutting and engraving acrylic, plywood, and some other non-metallic materials such as leather, fur, paper, cardboard, rubber, fabric, plastic. Due to the frame design combined with a reinforced bed (metal thickness is 2.9 mm), vibrations are eliminated during operation. This affects positively at cutting and engraving quality.
3-phase steppers and ¼ belt gearboxes guarantee accuracy during engraving. The service life of these engines is about 3 years and more. The machine is equipped with the Fotek inductive sensors with the actuation distance of 5 mm. This prevents collision of the gantry elements and its dislocation when cutting acrylic. A through-cutting is available: you can process material of any length.
The Wattsan 6040 ST
| Work area | 600 x 400 mm |
| Tube power | 80-90W |
| Max engraving speed | 500 mm |
| Dimensions | 765 mm * 1165 mm * 600 mm |
A medium-format model. It is intended for medium-scale production of items made from acrylic, plywood, wood, and other non-metal materials. The frame design and 3-phase steppers with ¼ belt gearboxes ensure high quality of cutting and engraving acrylic. The reinforced rigid bed eliminates vibrations providing a clean cut. For easier adjustment, the machine is equipped with universal laser tube fastenings with a measuring scale and an adjustment screw.
The Wattsan 6090 LT
| Work area | 900 x 600 mm |
| Tube power | 80-90W |
| Max engraving speed | 700 mm |
| Dimensions | 1030 mm * 1490 mm * 670 mm + 315 mm (if on its wheels) |
A medium-format laser machine. It comes with two types of nozzles: for cutting and engraving. This ensures the highest quality of both cutting and engraving on acrylic. The machine is equipped with the Fotek inductive sensors.
The Wattsan 6090 ST
| Work area | 900 x 600 mm |
| Tube power | 80-90 W |
| Max engraving speed | 700 mm |
| Dimensions | 1030 mm * 1490 mm * 670 mm + 315 mm (if on its wheels) |
A one of the most popular models in the Wattsan production line. The universal working area size, 900×600 mm, allows you to machine both small and quite large workpieces. The machine is widely used in workshops and production facilities. An 80 W laser tube is capable of processing quite thick material. The machine frame is fired that guarantees its durability. The safety of operation is ensured by installing the Fotek inductive sensors, which prevent collisions of gantry elements.
The Wattsan 1290 ST
| Work area | 1200 x 900 mm |
| Tube power | 100-120W |
| Max engraving speed | 700 mm |
| Dimensions | 1410 mm * 1790 mm * 670 mm + 315 mm (if on its wheels) |
A more powerful model that comes with a 100-120 W laser tube. It is equipped with 3-phase stepper motors and ¼ belt gearboxes, which provides high quality of engraving acrylic. Polyurethane hoses instead of silicon ones are installed on this machine like on the other Wattsan CO2 laser machines. Polyurethane hoses are more rigid and can withstand air pressure up to 6 bar; the bursting pressure is 8 bar. The hose is attached to the nozzle with a screw-in thread. This allows you to install a more powerful air compressor.
When can you cut acrylic in two passes?
It is not recommended to process acrylic or any other material on a laser machine in two passes. You should choose such parameters of power and speed that allow you to cut through the material in one pass.
For example, to cut the acrylic sheet of 15 mm, you should set up the higher laser tube power parameters than for cutting acrylic of 6 mm thick.
Contour engraving on plexiglas
When performing contour engraving on acrylic, you should turn off blowing. At the same time, it is necessary to monitor the process to prevent the flaming of emitted gasses. And after the engraving is done, you have to carefully clean the lens in order to remove acrylic vapor residue.
How to get rid of fouling and bloom when engraving acrylic.
When contour engraving on acrylic, a white coating is formed. To remove it, you can use acetone, mineral spirit or polishing-paste.
When using acetone, it is important to be very careful. If you wet a napkin too much and apply too much strength, the surface of the acrylic layout can melt.
Mineral spirit is a popular and quite cheap product. The risk of acrylic melting during processing is lower than when using acetone.
Engraving with soapy water
Soapy water can help you to achieve high quality engraving results. You should apply a very thin layer to the material and wait until it dries out. The engraving result will be perfect.
Should the film be removed?
In order to prevent the white coating from forming during the engraving process, you can leave the film on the acrylic sheet. However when producing small images, it is really hard to remove it later. Some pieces will stick to the material, and the product will have to be thrown away.
That is why it is important to understand what task you have to perform. When cutting large-sized parts, the film can be left on the acrylic sheet. Later, it can be easily removed.
