Hoping to get a little help with getting a relatively deep engraveing in 1/8 mild steel. Have a new gweike 50w fiber laser. Best settings ive found so far is in the ballpark of 90% power, 300 mm/s speed, 20khz frequency, cross hatch on, 5 passes. .03 line interval. Problem is its still not particularly deep. Im not new to lasers but this is my first fiber and im new to lightburn so trying my best to learn as i go. If anyone has any tips or tricks they could share id appreciate it!
Forget to specify the fiber laser is the gweike g2 max 50w
Gemini response on this, curious of the difference.
Deep engraving in mild steel with a 50W fiber laser requires a balance between material removal and heat management. While the current settings are a good starting point, there are several adjustments that can significantly increase the depth and efficiency of the process.
Optimizing Settings for Depth
To get a deeper engrave, the goal is to maximize the energy density while ensuring the laser is effectively clearing out the vaporized material.
- Frequency (kHz): 20kHz is generally on the lower end for a 50W unit. While low frequency provides higher pulse energy (good for “punching” into the metal), it can sometimes be too aggressive, causing slag to weld back into the trench. Try bumping this up to 30-40kHz to see if it provides a cleaner, more consistent material removal.
- Speed: 300 mm/s is actually quite slow for a 50W machine. If the laser stays in one spot too long, it creates a “melt pool” rather than vaporizing the metal. Try increasing speed to 500–800 mm/s and increasing the number of passes. More fast passes are often more effective for depth than fewer slow passes.
- Pass Count: 5 passes is very low for “deep” engraving. For a noticeable 3D effect or significant depth in steel, you are likely looking at 30 to 100+ passes.
Technical Refinements in LightBurn
1. The Wobble Feature
Since the G2 Max is likely using a Galvo head, check if LightBurn’s Wobble feature is enabled. This vibrates the beam slightly as it travels, which widens the trench and prevents the laser from getting “trapped” in a narrow deep line, allowing more material to escape.
2. Variable Hatch Angles
If you use the same hatch (cross hatch) repeatedly, the laser can create “ruts” that limit depth. Set your hatch to increment by 15° or 45° each pass. This ensures the laser hits the peaks of the previous pass rather than the valleys, leading to much faster material removal.
3. Focal Point Shifting
As you go deeper into the 1/8" steel, the laser will eventually fall out of focus.
- Manual Adjustment: Every 20–30 passes, you may need to lower the laser head by 0.1mm or 0.2mm to keep the focal point at the bottom of the trench.
- Z-Offset: If the machine has a motorized Z-axis controlled by LightBurn, you can automate this by setting a small “Z-step” per pass.
Summary Comparison Table
| Setting | Current (Image) | Recommended for Depth |
|---|---|---|
| Power | 90% | 90% - 100% |
| Speed | 300 mm/s | 500 - 800 mm/s |
| Frequency | 20 kHz | 30 - 45 kHz |
| Passes | 5 | 30+ (Loop until desired depth) |
| Hatch | Cross Hatch | Multi-angle (0°, 45°, 90°, 135°) |
| Pro Tip: Mild steel oxidizes quickly. If the engrave starts looking “crusty” or black, the laser is just burning the surface. Stop the job, quickly brush the area with a brass wire brush or wipe with IPA, and resume to ensure the beam is hitting fresh metal. |
1 Like
Thats interesting, thanks. I’ll use some of that info in my next round of testing. I suspected more passes would be necessary.
1 Like