Laser Cutter

The laser cutter is meant to cut or engrave many kinds of materials with a CO2 laser running at 60W. Applications for the laser cutter include prototyping parts, producing PCBs, etc.

Responsible

The person responsible for the use of the laser cutter is Anthony Antoun.

Keys

List of people who have a copy of the key of the laser cutter:

• Anthony Antoun
• Mauro Birattari
• Dhananjay Ipparthi
• Manuele Brambilla
• (Arne Brutschy?)

Use policy

Please note that you are not allowed to use the machine without an introduction to its use and safety procedures. The laser cutter is a very critical device and every lack of attention during its use might result in hazardous situations for the user, the machine and/or the lab. There is a strong risk of fire, even when working with the least dangerous materials.

Some materials produce highly toxic gases: any unknown material is therefore strongly prohibited.

Only people that are given a preliminary introduction by the responsible of the laser cutter can use it without external supervision, always under careful caution.

Instructions

Here is a list of good practices and measures that apply when using the laser cutter.

Before cutting/engraving:

• Wait for at least 5 minutes before firing the laser (warm-up phase).
• Ensure that the air filter is on before firing the laser. For extended use (>= 30 min), it is recommended to wear a mask as a personal safety measure.
• If possible: open the windows to create an air current and help evacuating the fumes outside the room.
• Always calibrate the height of the bed AFTER adding material in the laser cutter. This is done by using the 4.1 mm calibration tool.
• Always specify the settings in software (do not change them in the machine).

Note: The air filter can be configured as shown in the document near the laser cutter: HOLD both buttons until an LED indicator starts to blink and release, then hold one of the arrows to adjust the power. Please do not use the air filter at full power (level 6) for a long period. Using it at level 4 or 5 should be more than sufficient for many situations.

During cutting/engraving:

• NEVER OPEN THE DOOR

• Always keep an eye on the machine while working. Even the safest materials can produce an uncontrolled fire and damage the lens or other internal parts of the machine.

IN CASE OF FIRE:

If the fire lasts more than 3 seconds and does not follow the laser head:

• Press the RED BUTTON

If the fire didn't stop:

• Try to extinguish it by normal means (mouth blow - only with wood, paper or cardboard and very carefully).

In case of persistent fire, use the fire extinguisher.

After the cutting:

• Leave the door closed for a minimum of 3 minutes, with the air filter on.

After each use:

• Remove the material from the machine.
• Switch off the laser cutter, side interruptor (pumps), and computer.
• Do not leave your keys on the machine!

File formats and software

The software that allows uploading sketches on the machine is called LaserCut 5.3. It works with its own proprietary project format, as well as with other formats (AutoCAD, Illustrator, etc). Still, these formats are not considered as standard by the program - you have to import the sketches into the software to use them and edit them. One convenient format used is .DXF, which is the AutoCAD format.

More details on the upload and software will be provided by the administrator of the machine during the tutorial.

List of allowed people

Here is the list of people that can use the laser cutter without the supervision of the responsible of the machine:

• Anthony Antoun
• Arne Brutschy
• Mauro Birattari
• Dhananjay Ipparthi
• Roman Miletitch
• Touraj Soleymani
• Gianpiero Francesca
• Manuele Brambilla

Design considerations to take into account for laser cutting

While designing pieces to be laser cut, certain allowances should be given to the dimensions so as get pieces of particular dimensions. For example the laser beam has a particular diameter, therefore nothing smaller than the laser beam diameter can be cut. The general specifications of the cutter can be found at LS 6090 Laser Cutter product page. In addition, some tests have been conducted and the following observations were made:

• While cutting acrylic sheets of 3mm, and extra 0.3mm should be given to each dimension. Therefore, if a 10mm square has to be cut, each side should be increased to 0.15 + 10 + 0.15.
• While cutting 3mm MDF sheets, an extra 0.35mm should be given to each dimension. Therefore, for a 10mm square, each side should be increased to 0.175 + 10 + 0.175.
  • To create slits for create 3d structures via "slot in" for 3mm MDF use slits between of 2.80mm (tight) and 2.85mm (loose), tests performed with power 98 speed 12.
• Assuming the laser cutter cuts in the XY plane, the cuts along the X-direction and Y-direction will not be the same.
• The intensity of the laser is not uniform on the cutting bed. The cuts have lesser errors in the Upper Left and Lower Right regions of the bed.