<p>I don't see one square with bars, I see two overlapping squares, as illuminated here:</p>
<p><a href="https://i.sstatic.net/Fd7lD.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Fd7lD.png" alt="A red and yellow marking on two overlapping squares" /></a></p>
<p>The reason for them might be manifold, but to me, it seems the most likely cause is bad focussing or a mechanical issue, where between two passes the laser or workpiece were moved by a tiny amount. You also see this offset with the Y you see that there are two lines that are separated by the same distance as the two boxes are shifted to one another.</p>

CC BY-SA 4.0
2023-08-23T12:39:51.413Z
Very interesting. I think these were marked with only one pass. If we look at the letter "e," it also has that dark and lighter shading even though it was one pass. Does seeing this change or confirm any of your suspicions? The workpiece isn't flat. Could that be the cause?
Shades
CC BY-SA 4.0
2023-08-23T10:31:33.230Z
2023-08-23T10:31:33.230Z
Trish
<p>I just got a <strong>20W MOPA fiber laser</strong> and of course the first thing I do is mark color on <strong>stainless steel</strong>.</p>
<p>The center of the squares pictured are the color for which I set the settings. I am wondering why there are those columns of other color on the left and right sides.</p>
<p><a href="https://i.sstatic.net/s07wt.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/s07wt.jpg" alt="enter image description here" /></a></p>

<laser>
Color phenomenon with MOPA Fiber laser on stainless steel
Shades
# Color phenomenon with MOPA Fiber laser on stainless steel

(Asked by: username_0 on 2023-08-22)

I just got a **20W MOPA fiber laser** and of course the first thing I do is mark color on **stainless steel**.

The center of the squares pictured are the color for which I set the settings. I am wondering why there are those columns of other color on the left and right sides.

[![enter image description here](https://i.sstatic.net/s07wt.jpg)](https://i.sstatic.net/s07wt.jpg)

**Tags:** laser

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## 1 answers

### Answer by username_1 on 2023-08-23. Score: 2

I don't see one square with bars, I see two overlapping squares, as illuminated here:

[![A red and yellow marking on two overlapping squares](https://i.sstatic.net/Fd7lD.png)](https://i.sstatic.net/Fd7lD.png)

The reason for them might be manifold, but to me, it seems the most likely cause is bad focussing or a mechanical issue, where between two passes the laser or workpiece were moved by a tiny amount. You also see this offset with the Y you see that there are two lines that are separated by the same distance as the two boxes are shifted to one another.

> **Comments:**
> **username_0**: Very interesting. I think these were marked with only one pass. If we look at the letter "e," it also has that dark and lighter shading even though it was one pass. Does seeing this change or confirm any of your suspicions? The workpiece isn't flat. Could that be the cause?  

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