Reason

1. Reverse Offset/Scan Offset compensation settings Not Imported

Before you use the laser machine. Please remove the transparent bag from the front of honey comb plate. The transparent bag has a set of USB flash drive, and an engraving test sample. The USB flash drive stores software, manuals, libraries, etc… that you will need. Reverse Offset/Scan Offset compensation settings for this specific machine are included. These settings needs to be entered into your RDWorks, LaserMaker and/or LightBurn settings to ensure the highest engraving quality.

For every laser machine, the setting is different. So please enter it to RDWorks/LaserMaker /LightBurn according to the card that came with the laser machine.

If you forgot where the gold card was placed or did not receive it, please see the screenshot of the reverse Offset/Scan Offset compensation settings in the USB stick that came with the laser machine.

How to enter it in RDWorks/LaserMaker/LightBurn:

RDWorks Path: Config>System Setting>Configuration
LaserMaker Path: Settings>Scanning offset adjust
Lightburn Path: Laser Tools>Device settings>Basic settings

Each Thunder Laser machine has slight differences in Scan Offset compensation settings, and every machine is specially adjusted for Scan Offset compensation settings before leaving the factory.

If the current Scan Offset compensation settings are not suitable, you can retest, find the appropriate value, and then write it into the controller.

Lightburn-Scan offset testing

2. Machine not placed stably

If the machine is not placed stably, or if there is vibration from the floor or working table, wavy patterns or unstable engraving lines may appear during processing.

This issue is usually more noticeable during high-speed engraving, fine line engraving, or large-area filling, where machine vibration can affect engraving accuracy and overall results.

When the machine is running, small vibrations from the motion system may become amplified if the machine body is unstable, causing visible vibration patterns in the engraving.

Recommended checks:

• Make sure the machine is placed on a stable, solid, and level surface
• Check that all four machine Leveling feet are fully and evenly touching the ground
  

3. Signal interference

Signal interference may also cause engraving ghosting wavy patterns, or double images, especially during high-speed engraving or complex patterns. This is often related to unstable data transmission, such as USB communication being affected by electrical noise, poor contact, or low-quality cables.

Recommended checks:

• Remove USB direct connection and use Ethernet (network cable) instead for more stable communication and better anti-interference performance
• Check all connectors (USB, Ethernet, power, and signal terminals) and make sure they are firmly plugged in with no looseness or oxidation. To further ensure the file is transferred successfully and completely, please go to the File page on the control panel, select the file, and open the layer preview to check whether the design displays correctly.
  

•  Check whether ferrite cores are installed on the wires connected to the controller (D1 and D2 ports) and the Servo Drivers. A ferrite core is essentially made of high-permeability ferrite. When high-frequency currents pass through it, the bead generates impedance that absorbs high-frequency interference as heat. Ferrite cores help suppress high-frequency noise, reduce signal crosstalk, and improve system stability.
  

4. Dirty or Loose Mirrors and Lens

Dirty or loose mirrors/lens may also cause ghosting issues, blurry lines, weak edges, double outlines, or uneven engraving results.

 

If a lens is not securely fixed, machine vibration during operation may cause the lens to shift slightly. This can affect the laser beam path and positioning accuracy, resulting in unstable lines, ghosting, or vibration patterns. Please check that all lenses are securely installed. Make sure the lens is not loose, moving, or vibrating during operation.

Using a clean lint-free cloth over your finger, gently press on the edge of the lens to check whether it is loose or moving. If the lens shifts or wobbles, it is not properly secured and should be tightened.

Turn the retaining ring counterclockwise to loosen the lens. Turn the retaining ring lockwise to secure the lens. Do not overtighten the retaining ring, as this may damage the lens or the retaining ring.

In addition, after removing the lens for cleaning, the lens may not be fully tightened during reinstallation. A slightly loose lens can move during engraving and cause ghosting problems.

It is recommended to clean both sides of the lens using cotton swabs or lens wipes with lens cleaner.

After reinstalling the lens, make sure it is secured properly, but avoid overtightening the retaining ring.

Note: Please pay attention to the orientation of the focus lens during installation and make sure it is not installed upside down. Please make sure the focus lens is installed with the convex side facing up (toward the laser source) and the concave side facing down (toward the material).

Window lens	Mirror	Focus lens
Beam combiner and beam expander

5. Laser head assembly tilt

A tilted laser head can also cause engraving or cutting issues such as ghosting, beam shift, or uneven edges. If the laser head is accidentally bumped, moved during transport, or becomes loose over time, its mounting angle may change.

6. Loose belts

A loose belt may also cause wavy patterns or vibration marks during engraving.

If the belt tension is too low, the laser head may vibrate or shift slightly during acceleration, deceleration, or high-speed movement, affecting motion accuracy and engraving quality.

Please check:

• Whether the belt tension is correct
• Whether the belt mounts and tensioning mechanism are secure
• Whether the belt shows signs of wear, cracks, or stretching

Proper belt tension is important for accurate motion and consistent engraving results.

Regarding how to adjust the tension of the X-axis belt, please refer to the video below.