Week 03: Computer Controlled Cutting¶

Here is the group assignment for this week:

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.

For this week’s group project, we had to learn and explain different parts of how laser cutters work. Moreover, we also studied key laser cutter settings like focus, power, speed, resolution, cut width, and fitting space.

This is the laser cutter that we have in our lab.

Some more details about the laser cutter:

Work area: 24 inches × 12 inches (space where materials are placed)

Max material thickness: Up to 7 inches

Camera: One overhead camera to help position designs

Connectivity: Wired connection to computer

Resolution: Adjustable from 75 to 1200 dots per second (dpi) for engraving quality

Engraving speed: Up to 120 inches per second for fast cutting and engraving

Settings control: Speed, power, frequency, and cutting modes can be customized using color mapping

Internal storage: Can save multiple files up to 1 GB

Cutting modes: Raster (engraving), Vector (cutting), or both combined

Auto focus: Automatically adjusts laser focus for material thickness

Ventilation: Requires an exhaust system to remove smoke and fumes

We began by experimenting with different power and speed values to see how they affect engraving.

Power: Can be defined as the intensity of the laser beam or the amount of energy released by the laser.

Why does it matter?

If power is too high, the laser might burn or melt the material.

If power is too low, it might not cut or engrave deep enough.

Speed: Is the rate at which the laser moves across the material.

Why does this matter?

If speed is too slow, the laser stays too long and can burn the material.

If speed is too fast, the laser might not cut or mark properly.

Here are the steps:

We started by making this design on Inkscape and then labeled each shape with different power and speed settings.

This is the setting we used.

While printing, you have to use the pink frame (on your computer) to print one shape at a time with the specified power and speed setting.

Here is the outcome! 😉

In the first row, we kept the speed constant while decreasing the power. We noticed that as the power decreased, the cut also got lighter and lighter.

When the power decreases, the intensity of the beam also decreases, which is why the cut appears to be lighter.

In the second row, we kept the power constant while decreasing the speed value. We then noticed how, when the speed decreased, the cut got darker and darker.

When the speed decreases, the laser interacts more with the material, which is why the cut appears to be darker.

Measuring Kerf

Kerf is the amount of material removed by the laser when it cuts.

A good way to understand why kerf matters is when making press-fit designs. Kerf makes the slot a little bigger, so the pieces don’t fit tightly and become loose. Therefore for accurate and precise cuts, this is crucial to know.

To determine the kerf of our laser cutter, we first started by creating a comb (With known dimensions) on Inkscape.

Next, we printed it out and measured the dimensions again with the help of a caliper.

We then calculated the kerf

This is the formula that we used:

Kerf = (Actual cut - Intended cut) / 2

After using the formula, this was our result!

In the end, we got a kerf of 0.104 mm. 😄

As rewarding as a laser cutter may be, they can also be quite dangerous and pose several hazards:

Fire risk if materials catch fire
Fumes from burning materials can be harmful
Burns from the hot laser or materials
Eye damage from the laser beam

Here are some precautions that one must take to prevent such hazards:

Keep the work area clean and free of flammable stuff
Use proper ventilation
Don’t leave the laser cutter unattended while running
Never look directly at the laser beam
ALWAYS keep a fire extinguisher in close range!