How to Adjust Z Focus on Your Laser Galvo (3 Easy Methods)

⚡ The Quick Answer

Why is my laser mark weak or blurry?

90% of the time, the issue is Focus.

Laser marking is like using a magnifying glass to burn a leaf with the sun. If the distance isn’t perfect, nothing happens. You must adjust the Z-Axis (height) so the laser beam converges exactly on the surface of your material.

The Golden Rule:

• Double Red Lights: Adjust height until the two red dots become one.
• No Red Lights? Listen for the loudest hissing sound while marking a test square.

Best for: HeatSign HS-FL Series and most modern fiber lasers.

Most HeatSign machines come equipped with a dual red-light pointer system. This is the fastest way to find focus without measuring.

1. Place Your Material: Put the object you want to mark on the worktable.
2. Turn on the Red Light Pointer: Ensure the machine is on. You should see two distinct red dots (or a red box and a red dot) on your material surface.
3. Crank the Z-Axis Handle: Rotate the wheel on top of the tower to move the laser head UP or DOWN.
4. Watch the Dots: As the head moves, the two red points will move closer together.
5. Stop When They Overlap: Continue adjusting until the two dots merge perfectly into one single bright point.
   • Note: If they cross each other and separate again, you went too far. Go back.
6. Lock it Down: Your machine is now in focus for that specific material height.

Pro Tip: If you change the material thickness (e.g., switching from a 1mm sheet to a 50mm block), you must repeat this step. The focal point is relative to the top surface of the part.

Best for: Machines where red lights are misaligned, or for verifying maximum power.

If your red lights seem “off” or you want to be 100% sure you are getting maximum power, use this manual method.

1. Draw a Black Square: Open your software (EzCad). Draw a simple 20mm x 20mm square. Hatch it (fill it) so it’s solid.
2. Set Continuous Marking:
   • Select the square.
   • Check the box “Continuous” (or “Light” in the mark parameter area to keep it looping).
   • Settings: Use standard power (e.g., Speed 500, Power 50%, Frequency 20).
3. Start Marking: Press “Mark” (F2). The laser will begin burning the square repeatedly.
4. Move the Z-Axis While Marking:
   • Slowly raise or lower the laser head while it is firing.
   • Listen: You are listening for the “hissing” or “buzzing” sound of metal vaporizing.
   • Look: Watch for the sparks.
5. Find the “Sweet Spot”:
   • When the sound is loudest and the sparks are brightest, you are in focus.
   • If the sound gets quiet or the mark fades, you are out of focus.
6. Stop and Measure: Once you find that peak intensity, stop the machine.

Best for: Quickly returning to a known setup.

Once you have found the perfect focus using Method 2, you don’t want to guess next time.

1. Find Focus First: Use the “Sound & Light” method to get a perfect mark.
2. Measure the Distance: Use a ruler to measure the distance from the bottom edge of the lens to the surface of the material.
3. Record the Number: Let’s say it is exactly 18.5cm.
4. Make a “Focal Stick”: Many operators cut a simple metal or plastic stick to exactly that length.
5. Next Time: Just place the stick between the lens and your part, lower the head until it touches, and remove the stick. Perfect focus every time.

⚠️ Common Pitfalls (Troubleshooting)

• “My red lights overlap, but it still doesn’t mark!”
  • Your red light pointers might be physically loose or misaligned inside the head. Use Method 2 to find the true focus, then adjust the screws on the red light pointers to match that distance.
• “I’m marking a curved surface (cylinder).”
  • Focus on the highest point (the peak) of the cylinder. If you focus on the edges, the center will be too close and burn too deep.
• “I changed the lens (e.g., from 110mm to 200mm area).”
  • Your focal distance has changed drastically! A larger lens needs a much higher distance (e.g., an F160 lens is usually ~210mm height, while an F254 lens is ~350mm). You cannot use the same ruler measurement.