17. Wildcard Week — Metal Laser Cutting¶
Overview¶
This week’s assignment was to design and produce something using a digital fabrication process not covered in other assignments, and to carefully document the entire workflow. I chose metal laser cutting because this process has not been covered in other weeks, and because my final project required a metal component to be fabricated.
My colleague Ani and I visited a large fabrication workshop in our city, where various metalworking machines were available. We were most interested in metal laser cutting and a metal bending machine. During the visit, operators answered our questions, introduced us to the machine’s structure, thoroughly explained safety rules, the machine’s specific characteristics, and walked us through the basic safety procedures.
Why this process is not covered in other assignments¶
In Fab Academy, the Computer-Controlled Cutting week covers cutting non-metal materials — cardboard, acrylic, fabric. Metal laser cutting is a fundamentally different process: high power (6 kW), a specialized industrial machine, and assist gas — none of which appear in other assignments.
Machine overview¶
We had the opportunity to observe how the laser beam processes a metal sheet with high precision and produces the required part.
Technical specifications¶
| Parameter | Value |
|---|---|
| Laser type | Fiber laser |
| Power | 6 kW (6000 W) |
| Model | 4015-6000W CNC Fiber Laser Cutting Machine |
| Laser source | MAX Photonics MFSC-6000 |
| Software | CNC control software |
| Supported file formats | DXF, DWG, AI and other vector CAD files |
| Working area | 4000 × 1500 mm |
| Max material thickness | Up to 20 mm |
Control panel¶
The machine had a dedicated control panel containing the safety button, power and control switches.
Emergency stop¶
An emergency stop button was presented to us — pressing it immediately halts the entire system.
Buttons and indicators¶
- Start (motion) button — activates the movement system, used for moving the laser head
- Laser button — activates the laser source, enables the cutting process
- Red indicator — shows that the machine is powered on
- Green indicators (lit) — show that the corresponding systems are active
Manual control panel¶
The machine also had a handheld manual control panel that allowed the operator to manually control various machine functions and the laser head. The panel included laser activation and control buttons, return/home function buttons, start/stop controls, directional movement buttons, and various other functional buttons.
This panel was especially useful during the calibration phase — moving the laser head, verifying the cutting path, or setting starting points. It allowed precise control and made it easy to respond quickly to necessary adjustments.
¶
Nozzle selection¶
At the workshop we were told that smaller nozzles are mostly used — 1.2 mm, 1.4 mm, and 1.5 mm. Smaller nozzles provide more precise and detailed cuts, while larger nozzles are more suitable for thicker materials, as they remove molten metal from the cut more effectively.
Since we were cutting 1.2 mm thick metal, we used a 1.2 mm nozzle. Correct nozzle selection is critical — it directly affects cut precision and quality. With the right nozzle we achieved a clean, even cut without unwanted deformation or material damage.
Assist gas — air vs. oxygen¶
For cutting metal up to 3 mm with good quality, the compressor can supply sufficient air pressure. For metal thicker than 3 mm, an oxygen cylinder is required — it provides greater pressure to keep the laser path clear. If the metal is thick and air pressure is insufficient, the laser path will not clear properly and the nozzle will be damaged.
Safety rules¶
The machine operates at high temperatures and contains high-speed motion systems. Safety is essential for both proper workflow organization and hazard prevention.
- Wear protective eyewear at all times in the work area
- Do not stand near the moving rails — they move at high speed
- Do not touch moving parts while the machine is in operation
- Wait until the machine has fully stopped before approaching the work area
- Maintain a safe distance from the machine throughout the cutting process
Design¶
Since my final project includes a metal component, I decided to use this week to fabricate that part. Working from my sketch:
I used FreeCAD to generate the flat pattern (sheet metal unfolding) of the part. Several factors had to be considered — after cutting, the part needed to be bent with a press brake, and to ensure the correct bend angle without the material hitting an obstruction mid-bend, I reduced this section by 1 mm.
File preparation and transfer¶
After obtaining the final 2D file, I confirmed which formats the machine accepted. Both SVG and DXF were supported. I exported the file as DXF — widely used in laser cutting workflows — and transferred it to the machine via USB.
Setup and calibration¶
Part placement verification — Frame tool¶
After importing the DXF file into the machine’s software, it was necessary to verify that the part was correctly positioned on the metal sheet. For this we used the Frame tool, which instructed the machine to trace the outline of the area where the cutting would take place. This allowed us to confirm the placement beforehand and avoid material waste.
XY origin — limit switches¶
The X and Y limit switches (end stops) are typically located in the bottom-right corner of the machine. To set the XY zero, we first ran Calibration from the interface, then pressed CNC — the machine moves until it physically touches the limit switches and stops at its XY zero position.
Z-axis calibration¶
The next step was Z-axis calibration — setting the laser head to the correct distance from the material surface.
A notable feature of this machine: after Z-axis calibration, even if the metal sheet is slightly deformed or uneven, the machine automatically maintains the initial Z position throughout the cut. This does not affect cut quality.
Cutting parameters — Layer settings¶
Inside the Layer panel all cutting parameters are visible:
| Parameter | Description |
|---|---|
| Speed | Cutting speed |
| Power | Laser power (W) |
| Frequency (Hz) | Laser pulse frequency |
| Gap (mm) | Focal offset |
| Focus | Focal point position |
The machine comes with factory-preset parameters for each material thickness. However, the operator pointed out that even metals of the same nominal thickness (e.g. 1.2 mm) can have different densities, meaning the factory settings don’t always produce a clean cut. In his experience, the two parameters adjusted most often are speed and amperage. The rest are tuned based on cut quality — if slag (dross) appears on the cut edge, adjusting the focus is usually the first step to find the right setting.
Lead-in point¶
Before starting the cut it is important to define where the laser will pierce the material. This is critical because the piercing point leaves a small mark — if it lands on the part itself, it can damage the geometry.
My part had holes intended for bolts. For each hole I set the lead-in point to the center of the hole, with the appropriate settings applied. This way the pierce mark falls inside the hole and has no effect on the final part.
## Cutting
Once all settings were configured, we started the cut.
Bending¶
After successfully cutting the part, the next step was bending it using a dedicated press brake machine. This machine has its own safety rules and setup procedure.
Safety¶
The press brake applies very high pressure during operation. The most important safety rule is to keep hands away from the machine at all times while it is working, and to ensure that no bystanders are near the machine. Inattention can cause irreversible injury.
Setup¶
The operator walked us through the process step by step. First, we selected the appropriate dies (punches) based on the bend length required, and mounted them on the machine.
The part is placed into the die, and the central element of the die — the punch — determines the bend angle. We increased the angle gradually, a little at a time, to avoid overbending the part.
Result¶
Reflections¶
- Nozzle diameter should match material thickness — a 1.2 mm nozzle for 1.2 mm metal gave a clean result
- Compressed air is sufficient for metal up to 3 mm; oxygen is required for thicker stock
- FreeCAD sheet metal unfolding requires accounting for bend allowance before cutting
- The Frame tool is a simple but effective way to verify placement and avoid wasting material
- Factory presets are a starting point, not a guarantee — speed and amperage are the main variables to tune
- If slag appears on the cut edge, adjusting the focus is the first thing to try
- Always set the lead-in point carefully — piercing inside a hole prevents damage to the part geometry
- The automatic Z-axis compensation is a significant advantage for real-world material that is not perfectly flat
- When bending, increase the angle gradually — overbending cannot be undone