Week 03 — Computer-Controlled Cutting

Learning Outcomes

Evaluate and select 2D software
Demonstrate and describe processes used in 2D design for cutting
Identify and explain processes involved in using the laser cutter
Develop, evaluate and construct a parametric construction kit

Group Assignment – Computer-Controlled Cutting

This week's group assignment consisted of performing safety training and characterizing the laser cutter parameters, including focus, power, speed, kerf and joint clearance.

The complete documentation of the group work can be found in the following page:

View group assignment documentation

Individual assignments

1. Machine Review and Design Considerations

At the beginning of the process, a review of the laser cutter was conducted to understand its capabilities and limitations. This included checking the ventilation system, cleaning the working area, verifying the focus distance, and reviewing emergency and safety procedures before operation.

The work was carried out using a Trotec Speedy 300 laser cutter at the digital fabrication laboratory of PUCP. This professional CO₂ laser system is designed for high-precision cutting and engraving and offers:

Working area: 726 × 432 mm (29 x 17 pulgadas)
Laser type / power: CO₂, up to 80 W
Maximum speed: up to 4.3 m/s
Precision optics: suitable for detailed engraving and fine cuts
Compatible materials: wood, MDF, cardboard, acrylic, leather, rubber, textiles, and more
Safety: integrated exhaust and safety system for controlled operation

For the digital workflow, the geometry was initially developed in Rhinoceros. The 2D vectors were then exported to Adobe Illustrator for line organization, color coding, and scale verification. Finally, the file was prepared and sent to the laser cutter using CorelDRAW, which is the software interface used by the Trotec Speedy 300 to define cutting and engraving parameters.

Understanding the complete software-to-machine workflow was essential to ensure correct vector interpretation, proper layer assignment (cut vs. engrave), and accurate parameter configuration before fabrication.

Key design parameters considered before cutting:

Material thickness consistency
Kerf compensation
Minimum feature size
Corner behavior (sharp vs. filleted edges)
Power and speed balance
Vector preparation (closed paths, no duplicated lines)

Considering these factors was essential to ensure precise, clean, and safe cutting results.

2. Material Exploration

I experimented with two different materials: cardboard and MDF. Cardboard allowed quick prototyping and testing of joint tolerances due to its flexibility and low cost. MDF provided a more rigid and structural result, closer to the intended final application.

This comparison helped evaluate:

Cut quality and edge finish
Structural stability
Fit resistance in press-fit joints
Burn marks and surface behavior

3. 2D Design — Base

I designed the base structure of the construction kit to be assembled using adhesive. To facilitate the assembly process, engraved numbers were incorporated into the pieces to serve as guides for correct alignment and positioning.

Design software: Rhinoceros
Laser interface software: CorelDRAW (used to send the file and configure cutting parameters)
Material used: MDF
Nominal thickness (T): 2.00 mm

4. Laser Cutting

Before starting the cutting process, a general inspection of the laser cutter was performed to ensure safe and optimal operation. This included verifying the cleanliness of the working bed, checking that the lens and mirrors were free of debris, and confirming that the extraction and filtration system was functioning properly. Once the machine was ready, the material was placed on the platform and properly aligned. The focus height was then calibrated to ensure accurate cutting and consistent energy distribution across the surface.

The file was prepared using the laser interface software Trotec JobControl, where the cutting parameters were assigned. In this workflow, different colors correspond to specific settings such as power, speed, and frequency, allowing the laser to distinguish between cutting and engraving operations.

After starting the job, the cutting process was continuously supervised to ensure the operation was proceeding correctly and safely, monitoring cut quality and watching for any signs of material burning or incomplete cuts. Once the cutting process finished, a short waiting period was observed before opening the machine and removing the material, allowing fumes to be extracted and the material to cool down safely.

Laser Parameters — MDF 2 mm (Trotec Speedy 30)

Operation	Power	Speed	Frequency	Resolution	Passes	Air Assist
Vector Cutting	80 – 90 %	1.0 – 1.5 %	1000 Hz	—	1	ON
Raster Engraving	20 – 30 %	80 – 100 %	—	500 dpi	1	ON

Recommended starting parameters. Final values may vary depending on MDF density, moisture content, and machine calibration.

Laser Parameters — Corrugated Cardboard (Trotec Speedy 30)

Operation	Power	Speed	Frequency	Resolution	Passes	Air Assist
Vector Cutting	40 – 55 %	2.5 – 4.0 %	1000 Hz	—	1	ON
Raster Engraving	10 – 18 %	90 – 100 %	—	300 dpi	1	ON

Starting parameters for corrugated cardboard. Adjust according to thickness, flute type, and burn sensitivity.