Is your laser engraver skipping lines during engraving and producing visible horizontal or vertical lines throughout the project?
Don’t fret! I’ve been there too.
The skip lines in an engraving are caused due to improper belt tension, i.e., the belt is either too tight or too loose.
I’m Unni, and I’m a laser engraving expert. In this guide, I will explain how to set the proper belt tension to avoid skipping steps, thereby ensuring perfect engraving outputs.
X-axis or Y-axis? Identify Which Belt is Causing the Issue
| Issue | Cause | Remedy |
|---|---|---|
| Lines parallel to the X-axis | Improper belt tension on Y-axis | Fix belt tension on Y-axis gantry |
| Lines parallel to the Y-axis | Improper belt tension on X-axis | Fix belt tension on the X-axis gantry |
| Unwanted lines with loud noise | Faulty stepper motor | Replace the faulty stepper motor |
To identify which belt you need to rectify, analyze the lines produced in the engraving output.
Generally, these lines are uniform, and the orientation of the lines can help you identify which axis needs the belt tension adjustment.
If the engraving orientation is set to 0º, i.e., the laser moves in a to and fro movement along the X-axis, and you get vertical skip marks in the engraving, then the belt on the X-axis gantry needs tension adjustment.
In contrast, if the skip marks are horizontal, then the belt on the Y-axis gantry needs adjustment.
Adjusting the Belt Tension- The Remedy!
To adjust the belt tension, you first need to know whether the belt is too tight or too loose.
Generally, if the laser is skipping lines, then the belt is too tight, which makes it undergo jumps instead of a smooth movement.
On the other hand, if the laser is producing dark lines, i.e., overburnt lines, then the belt is too loose, and the laser is skipping steps, which makes it engrave over the same line more than required.
Depending on the type of machine you use, there are different mechanisms to adjust the belt tension.
Generally, most diode lasers come with an eccentric nut that you can tighten or loosen, which eventually moves the corresponding pulley to tighten or loosen the belt.
When adjusting belt tension, use your fingers to gently press the belt and feel the tension. It should neither be too loose nor too tight.
Another way to test belt tension is to tilt the laser at 45°, and the laser gantry should glide down the slope smoothly.
If the gantry does not slide down, the belt is too tight, and if it slides down abruptly without a smooth glide, then the belt is too loose.
What if the Issue Does not Resolve even with Perfect Belt Tension? Worst Case Scenario!
If you notice the issue still persists even after setting the optimal belt tension, then it is time to look for other culprits.
One such culprit is a faulty stepper motor.
A faulty stepper motor can skip steps which can result in overlapping of engraving, producing dark lines in the engraving.
You can identify this issue by loud or unusual noise produced by the machine during operation. This noise can either be due to damaged bearings or a worn-out stepper motor.
In that case, you will have to either replace the damaged bearing or replace the worn-out stepper motor to rectify the issue.
However, if you have set the right belt tension and the stepper motor seems to be running just fine, then the possible reason can be a worn-out belt.
The belts used on lasers are durable and can last a long time, but due to certain circumstances like improper tension, poor maintenance, or even climatic conditions, the belts can wear out.
In that case, you need to replace the belt.
Note: When replacing the belt or motor, make sure to look for the one with the exact same configuration because any change in the configuration of the belt or motor will have to be manually adjusted in the controller settings of the laser.
