Week 3 Computer controlled cutting

In the third week, we begin to know and use the machine. I learned the laser cutting machine in the school very quickly, very happy. It can be cut out a lot of interesting shapes according to the 2D design and combined into different works.

Learning Objectives

Group assignment:
- Do your lab's safety training
- Characterize your lasercutter's focus, power, speed, rate, kerf, joint clearance and types.
Individual assignment:
- Design, lasercut, and document a parametric construction kit, accounting for the lasercutter kerf, which can be assembled in multiple ways.
- Cut something on the vinyl cutter.

1.Laser Cutter

1.1 Our School's Laser Cutter: xTool P2

Laser cutting is a manufacturing process that uses high-power laser beams to precisely cut materials. It has the characteristics of high precision, fast cutting and strong flexibility.

Feature	Description
Core Functions	Precision cutting, efficient engraving, multi-material compatibility
Cooling Method	Built-in air cooling system
Applicable Materials	Wood, acrylic, leather, paper, fabric, etc.
Positioning Accuracy	±0.05mm
Processing Area	300mm × 240mm
Movement Speed	Up to 10,000mm/min
Laser Power	20W (adjustable)
Intelligent Operation	Auto focus, camera-assisted, one-click operation
Minimum Line Width	0.1mm
Software Support	Compatible with SVG, DXF, JPEG, provides cloud material library
Cutting Thickness	Varies by material (e.g., acrylic: 10mm; wood: 15mm)
Safety Design	Fully enclosed body, emergency stop button
Operating Voltage	100-240V AC
Applications	Creative design, educational field, commercial application

1.2 Key Parameters of Laser Cutting

Parameter	Description
Power	Determines the energy intensity of the laser beam, affecting cutting speed and material thickness processing capability. Higher power results in faster cutting but also increases energy consumption and costs.
Speed	Controls the speed at which the laser head moves, affecting cutting quality and efficiency. Different materials require different cutting speeds; too fast may result in incomplete cuts, while too slow may cause excessive heating of the material.
Frequency	The frequency of laser pulses affects the fineness of the cut and the size of the heat-affected zone. For certain materials (such as plastics), appropriate pulse frequency can reduce thermal damage.
Assist Gas	Used to blow away molten material, keeping the cut clean. Commonly used gases include oxygen, nitrogen, and air. Choosing the right gas can optimize the cutting effect.
Focal Length	The focal length of the lens system determines the position of the laser beam's focus point, affecting cutting depth and precision. Longer focal lengths are suitable for thick materials, while shorter focal lengths are suitable for fine cutting.

1.3 Laser Cutter Safety Training

Completed safety training for the xTool P2 laser cutter, covering:

Emergency stop procedures.
Ventilation requirements.
Material compatibility and fire hazards.

2. Material Testing

Material A: 3mm basswood & B: 3mm acrylic

2.1 Optimal Power & Speed Testing

Test different materials for optimal power and speed. First of all, draw a 1*1cm square in the software of the laser cutting machine, the cutting process, set different cutting power and speed for each square, and finally, confirm the best power and speed.

2.1.1 Material A: 3mm basswood

Test results of 3mm thick Tilia wood board, relatively economical and efficient power | speed is set to 80% power, speed 35mm/s.

2.1.2 Material B: 3mm acrylic

3mm acrylic plate test results, relatively cost-effective power | speed set to 100% power, speed 10mm/s.

2.1.3 Test conclusion

Material	Power	Speed (mm/s)	Quality	Notes
3mm Basswood	80%	35	✅ Best	Clean edges, minimal charring
3mm Acrylic	100%	10	✅ Best	Smooth edges, no melting

2.2 Kerf Test

Test the cut of 3mm Tilia wood board, first of all, the laser cutting machine software draws 10 side by side 1*1 squares, after cutting, the square is closely arranged in the gap, and then use the vernier caliper to measure the size of the remaining gap, which is the sum of 11 cuts.

Test conclusion: Using power 80%, speed 35mm/s of 3mm Tilia wood is 16mm.

Basswood Kerf: 0.15mm per cut → Total 1.65mm for 11 cuts.

Design Adjustment: Compensate by offsetting paths by 0.15mm in CAD.

2.3 Joint Clearance Test

Test joint gaps of different materials. Laser cut the two materials of the comb joint test board, the width difference between the adjacent joints is 0.05mm, and then test with 3mm lime wood and 3mm acrylic plate, respectively, to see which seam is the best.