X and Y axis not aligned?

benjaminjkey · November 14, 2022, 5:31pm

Running on an OMTech 60W Blue/Gray
The top photo is what is displayed on the screen in Lightburn and the bottom is what is actually printing/cutting on the mdf. How would I go about getting this to properly align?
Thank you!

ednisley · November 14, 2022, 5:56pm

Because the lines seems short on both ends, perhaps the minimum power level for the layer is set to zero, so that the laser doesn’t come on until the head is moving faster than the minimum takeoff speed.

benjaminjkey · November 14, 2022, 6:41pm

Thanks! I adjusted the speed and it helped a little. This link was very beneficial for adjusting offset, which got me to 100%.

github.com

LightBurnSoftware/Documentation/blob/master/ScanningOffsetAdjustment.md#scanning-offset-adjustment

[Return to main page](README.md)

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# Scanning Offset Adjustment

Modern lasers are capable of moving very fast, and with remarkable precision, however firing the beam still takes time.  Some power supplies and tubes may respond in less than a millisecond, but many take longer.

At 100 mm/second, 254 dots per inch means your dots are 0.1mm in length, fitting 1000 of them in 100mm. At 100 mm/sec, if your power supply and tube take 1 millisecond to fire, your engraving will be offset by a full dot width.

At 500 mm/second, that 1 millisecond delay means you'll be off by 5 dots, or 1/2 a millimeter. Still not very much, but visible. Many power supplies and tubes will take even longer to fire.

The result often looks like ghosted edges.  The image below is a 20mm square at 1000 mm/sec, with a 1ms delay, resulting in a full mm of skew between scans:

![](./img/ScanningOffset-Illustration.png)



LightBurn has a setting to counter this, called Scanning Offset Adjustment, in the [Device Settings](DeviceSettings.md):

This file has been truncated. show original

berainlb · November 14, 2022, 7:33pm

Note that what you’ve done is different than what @ednisley is pointing out.

In your cut settings you likely have Min Power set to 0% or something less than 10%, below the threshold at which the laser can properly fire. If that’s the case the laser won’t be firing during the start and end of each line during acceleration/decelration. Raise the Min Power to match Max Power while you are testing this.

Your Offset Scanning Adjustment will likely end up obfuscating your results so be prepared for that.