Group Assignment on Computer-Controlled Cutting

1. Lab Safety Training

Before using the EPILOG LASER FUSION cutter at Oulu’s Super FabLab, we completed lab safety training, covering: - Fire hazards and emergency procedures (example, like where the fire extinguisher is placed). - Personal Protective Equipment (PPE) requirements. - Proper ventilation and fume extraction. - Handling of different materials to avoid toxic fumes. - Machine maintenance and safe operational guidelines.

Turn on the air flow to the laser cutter by pushing the green lever downward.

Power on the machine using the main switch and then turn it on from the machine itself.

2. Laser Cutter Raster and Vector Setting Printing Variations

Machine Setup Steps

• Power on the laser cutter with the lid closed
• The machine initializes before use.
• Ensure the emergency stop button is disengaged.
• After turning on the machine, wait 45 seconds before starting any cuts.

Our Fab Lab also has a mobile laser cutter (shown here with lid closed).

Ensure that the emergency stop button is disengaged.

To ensure the laser is properly focused, adjust the board height correctly: - Attach the focus tool to the laser head. - Use the joystick in the focus menu to move the board up or down. - When the focus tool barely touches the board, the board is at the correct distance from the laser. - Confirm the setting by pressing the joystick.

Before cutting, set the workspace origin to the upper left corner using the jog function. This determines where the laser cutting or engraving will begin.

The origin of the workspace is set using the Jog function. Confirm the new origin by pressing down the joystick. (Do this without the focusing triangle tool.)

• Design the files using vector-based software
• We used Inkscape for vector file preparation.
• Files were saved in .svg for compatibility.
• Files were saved in portable pdf for printing to the lasercutter printer.

Predefined settings can be loaded from the "Advanced" tab. After selecting a preset, you can modify the Raster Setting (engraving) and Vector Setting (cutting) as needed.

3. Laser Cutter Focus Variations with Power and Speed

Understanding Focus

Focus is crucial in laser cutting and engraving, as it determines how well the laser interacts with the material. - Correct focus: Produces clean and precise cuts. - Defocused (too high or too low): Results in blurred or incomplete cuts.

The effect of beam focus was tested. At the correct focus, the beam waist was minimized, resulting in the highest optical power per square meter (brightest). Several focal distances were tested. When the focal point was too far or too close, engravings became less sharp and weaker, and cuts failed to go through.

Power and Speed Considerations

• Power: Higher power results in deeper cuts but can burn the material.
• Speed: Faster speeds lead to shallower cuts and may require multiple passes.

The effect of laser power and speed was tested by cutting squares from 2.5 mm MDF. Four speed settings were tested at 100% power, and four power levels were tested at 10% speed. When the speed was too high or the power too low, the cuts did not go through.

Optimal Settings

Found by testing combinations of power, speed, and frequency on MDF materials (Medium-density fiberboard).

Laser Cutting Settings and Observations

Default Settings

Raster Settings

• Constant Speed Configuration:
• 1-P70 has the highest power (P70) and provides the best quality.
• Constant Power Configuration:
• 6-S20 has the best quality due to a slower speed, causing more depth and increased burning of MDF.

Parameter	Value
Speed (S)	80
Power (P)	25
Frequency	50

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Vector Settings

Parameter	Value
Speed (S)	10
Power (P)	100
Frequency	100

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Cutting Results and Observations

Speed Variations

Speed Setting	Power	Observation
S10	P100	Cut cleanly but had burnt surfaces on the thickness of the MDF.
S7	P100	Cut cleanly with lesser burnt surfaces on the MDF thickness.
S17	P100	Cut cleanly with minimal burnt thickness.
S30	P100	Reduced speed resulted in failure to cut through.

Power Variations

Speed Setting	Power	Observation
S10	P100	Cut cleanly but still had burnt surfaces on MDF thickness.
S10	P20	Reduced power prevented it from cutting through.

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Summary

A picture of the EPILOG printer dialogue box, would give a clearer view of the preset settings for vbarious materials, already locked in, and also white boxes for us to enter our desired speed, power and frequency, whether for Raster or vector settings (Note raster settings frequency is fixed at 50, so it is greyed out).

The below is our generalization of the combination of speed and power:

• Higher power generally led to cleaner cuts but increased burning.
• Lower speeds helped with depth but sometimes failed to cut through.
• Optimizing speed and power is crucial for achieving the best cut quality.

4. Laser Cutter Kerf, Joint Clearance, and Types

Measuring Kerf

Kerf is the width of material removed by the laser. This means that holes will be slightly larger than designed, and cut-out pieces will be slightly smaller by the kerf value. One way to calculate the kerf value for a specific material and settings: (hole width - square width) / 2. We tested different settings to measure kerf width and adjusted our designs accordingly. A caliper can measure object thickness and hole diameter. Using a higher-quality caliper provided more consistent readings.

A micrometer provides better accuracy and precision for thickness measurements but cannot measure hole diameters.

• Adjusted designs by offsetting paths in software to compensate for material loss.

Joint Clearance with different materials

We explored different joint clearance with the MDF and cardboard. Cardboard was more forgiving and fitted easily, when we miscalculated the kerf, but with MDF, we had to be wetin with our calculations.

5. Additional Observations and Learnings

• The material type significantly affects laser settings; acrylic requires slower speeds and higher power compared to wood.
• Multi-pass cutting can reduce burn marks while achieving deeper cuts.
• Raster engraving and vector cutting require different power settings for optimal results.
• The focal height plays a critical role in engraving depth and cutting precision.
• It was observed that for the EPSON laser cutter, an assumption of 0.15mm was safe for MDF kerf.

6. Conclusion

This group assignment provided practical insights into laser cutting parameters, joint fitments, and safe operation procedures. By understanding how power, speed, and focus affect cutting and engraving results, we refined our approach to designing precise and reliable laser-cut components.