Speed setting, I'm a little confused by adding a higher speed and it taking longer to complete the project

I’m using the atomstack x30 and I wanted to check speed engraving things. So I found an image, set my power to 50 and my speed to 10000. It took about 12 minutes (4x5 image). I took the speed up to 15000, and it actually took 14 minutes. If I take it up to 20000 and I get 16 minutes. So I played around with settings until I found that 6500 was about the best that I was going to get before things started taking longer…and at 6500, it ended up being 11:45.

I guess I’m now confused by the ‘speed’ setting. Am I missing something?

The gotcha for engraving happens in the overscan area on either side of the thing you’re engraving. In order to maintain a constant speed across the engraving, the laser head must accelerate from a dead stop off to one side, cross the engraving area, then decelerate to a dead stop on the other side.

Then it repeats in the other direction, over and over again.

The faster it moves, the longer it takes to speed up and slow down. Ask it to go crazy fast and it’ll spend most of the day outside of the engraving area, getting ready to zip across at top speed.

If you restrict the overscan area enough, then the hardware can’t get up to speed and will produce overburned areas along the sides.

If you increase the acceleration settings enough, the motors will stall because they can’t produce enough torque to get the laser head up to speed.

If you increase the motor current to increase the torque, the motors will become scary hot or the drivers will burn out.

The controller settings limit the actual top speed, but the laser power and material limit the practical top speed to a much lower value.

Find a speed / power combination that produces the result you want and run with it …

@ednisley is correct. If you take the first design and view it in preview, enable show transverse moves, it will give you a reddish orange color where the head moves and it’s not burning…

Now change the speed and re-run it in the preview, you can see it’s traveling further to compensate for getting it up to speed.

This is also relative to your acceleration values… below is 40,000mm/s2 compared to 6,000mm/s2

The same thing happens when you increase speed without adjusting acceleration… covering more areas to change speed/direction. Notice the difference in time, about 4 minutes faster with a higher acceleration value.

The acceleration value is related to how much power can be supplies to the motors…

Make sense?

Use the preview, one of the greatest, least used options in Lightburn.


Thank you, that is incredibly informative. It makes sense…I wonder if this can ever be overcome. I wonder if having a laser 16 inches from the surface could be a way to get around it. Probably not…but thanks for answer my question with so much detail.

I use it more than anything else…and you’re right, I noticed the red getting larger…that makes sense!

Congratulations! You’ve just invented the galvo laser! :grin:


I figured there was something to it.

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