Computer Controlled Cutting

1- Laser lab safety

Before operating the EPILOG LASER FUSION cutter at Oulu’s Super FabLab, we participated in a comprehensive lab safety training session from Behnaz. The training included: 1. Awareness of fire hazards and emergency response procedures (e.g., identifying the location of fire extinguishers). 2. Importance of proper ventilation and fume extraction systems. 3. Safe handling of materials to prevent exposure to toxic fumes. 4. Guidelines for machine maintenance and safe operating practices. 5. During cutting process, always be aware and keep your eyes on the laser cuuter

1.Check and read the device tutorial and at least read the safety section. 2.Turn off the power or gas source. 2.Pull the tabs to release the blanket. 3.Approach the fire carefully with the blanket as a shield. 4.Cover the burning object completely. 5.Leave the blanket in place to cool. 6.For a person on fire — wrap them in the blanket, help them lie down, and call for help.

This is a fire blanket , designed to stop small fires by smothering them:

During the Laser Cutting and Engraving Process the following safety rules should be applied: First, ensure that the air input and output are open (see instruction on the wall near the machine). Never cut unknown materials. Always consult the list of allowed /not allowed materials. Never leave the machine unattended. At the end of the job, wait one minute before you open the lid. In this way you allow the toxic gases to be removed from the machine and not enter the room.

Proper ventilation and fume extraction are important because the laser cutter produces smoke and tiny particles when it burns material. Without good airflow, these fumes can build up, making the air unhealthy to breathe and leaving residue inside the machine. The extraction system removes the smoke quickly, keeps the workspace safe, protects your lungs, and helps the machine stay clean and work longer.

Fig1 - Vent tubes Fig2 - Vent holes

We need to wait around one minute to open the lid after a laser cut:

Fig3 - Keep the lid closed at least for 1 minute after the cut

Behnaz reminded us not to press the Emergency Stop button unless an instructor specifically tells us to do so. It is meant only for serious emergency situations, such as a large fire. Pressing it immediately cuts all power to the machine, which also stops the cooling system. This can damage the laser tube, so the button should only be used when there is no other safe option.

Power and Speed affect: Raster and Vector

Before we will begin measuring it, we should understand what "Kerf" is. Definition is fairly simple. Kerf is a slit or notch made by a saw or cutting torch. What does it mean? Kerf is just a term to describe reality. Everything in real world has some dimensions. There are no infinitely small lines. Cutting elements have some width and if you won't pay attention to it for sure your elements won't match. It means from the 'inside lines' you should subtract this value and from 'outside shapes' you should add kerf lukasz Surazynski.

Some basic setting before using the laser cutter. Put the laser beam on the target point as a origin for start cutting, trying to not waste material. Do focusing test. put the material sheet inside the laser cutter plate and be sure that it is flat as has to be, without any curving. Switch on laser beam. Prepare design and make it ready for cutting.

We did some test to see affect of laser power and speed of the head on cutting process. For this purpose we used 3 mm thick MDF. Just couple shapes, rectangle and circle will be enough. As a reference, the default values for the power (100) and speed (80) are used for the laser cutter in Oulu super Fablab.

For vector testing we follow the below power and speed values, S12 is the default value, we tested S7, S17, and S30. And for power, P80 and P20 were tested:

Here is the effect of different power and speeds:

The following tests are for Raster (engraving) testing. Default values for the laser cutter model (Epilog 75WATT), power (P100) and Speed (S80). two different powers (P70 & P40), and three different speeds (S90, S40, and S20). The value can be define as they were seen in the image above of vector setting:

Focus testing

Focus test in a laser cutter is a kind of calibration procedure used to determine the exact focal distance between the laser lens and the material surface to ensure the beam is concentrated at its smallest possible spot size. At least to me it is slightly difficult to do it, I think it should be normal and by working and having some experience it will be easer how exactly manage it. We did the test by cutting a series of small square while slightly varying the the laser point along to Z-axis (height).

By doing this test we understood that proper focus is critical because an unfocused beam spreads out, reducing power density, resulting in wider kerf, poor edge quality, incomplete cuts, resulting to wasted material. Maintaining correct focus ensures maximum cutting efficiency, precision, repeatability, and overall machine performance.