3. Computer controlled cutting¶
Group assignment:
- Characterize your lasercutter’s focus, power, speed, rate, kerf, joint clearance and types.
- Document your work to the group work page and reflect on your individual page what you learned.
This week, we worked with two machines: a vinyl cutter and a laser cutter.
Our instructor, Babken, emphasized the importance of reading the machine’s instructions before use.
Of course, the instructions contain a lot of information, but beforehand, we familiarized ourselves with the safety techniques for using these machines.
Laser Cutter¶
In our lab, the primary laser cutter is a Chinese CO2 laser cutter with CNC, with 80 Watts of power and a working area of 600x400mm.
Safety Measures¶
Since the laser itself can cause materials to ignite, it’s important to observe safety techniques, namely:
- Applying the Air Assist system when cutting materials.
- Never using the laser system unsupervised.
- Having a properly serviced and checked fire extinguisher nearby.
- Activating the water cooling system (water temperature should not exceed 35 degrees Celsius).
- Activating air purification filters.
Additionally, a list is printed on the laser cutter to help organize work with it more safely and correctly:
Technical Maintenance¶
Besides safety considerations, understanding the components of the laser cutter and its technical maintenance requirements is crucial for long-term and uninterrupted operation.
Our group assignment started with the technical maintenance of the laser cutter. Since we deal with cutting and engraving materials, dust accumulates inside and smoke settles. This particularly affects the laser beam, as it reaches its destination through mirrors and is focused at the end. Dirt on the mirrors and lens leads to incorrect laser operation, so if the laser is used frequently, cleaning the mirrors and lens once a week is necessary.
Special tools are available for cleaning the optics:
Here is a picture demonstrating the cleaning of the mirror:
Focusing¶
Focusing the laser on this laser cutter is done manually.
There’s a specific button, the Laser Switch, to turn on the laser.
In normal mode, if the button is activated, a regular red beam is emitted, which aids in laser focusing.
On the side of the laser cutter, there are two buttons for raising and lowering the table.
Using these buttons, the table should be adjusted so that the red beam is centered:
Kerf¶
To calculate the laser cutter’s kerf, we designed two squares, one inside the other, with sides of 10mm and 20mm.
Afterward, we measured the squares with a caliper and found that the square was 0.25mm smaller than intended.
This means that to create a part of the necessary size, the laser’s kerf size must be taken into account.
Let’s make a square that will be 10mm after cutting. To do this, an offset of 10mm square by 0.25 / 2 = 0.125mm is required.
Speed and Power for Engraving¶
Since there were no instructions provided with the laser cutter to find preliminary parameters for speed and power for different types of materials, we decided to conduct tests, adjusting the laser’s speed and power to find optimal parameters for engraving cardboard.
For this purpose, we created a table and set speeds of 200, 250, and 300 mm/sec, as well as power from 20 to 10%, decreasing power by 2% at each step.
And here are the results we obtained:
