I’m newer to the game so m just figuring things out by trial and error. Working with an 120w CO2 Laser. I’m just trying to understand the relation or purpose of a faster speed takes longer to engrave. I am assuming that the faster the speed would create better quality engraving but to confirm that would be great or if I’m totally wrong, I’m just as curious. Thanks!
The faster the head moves, the more time it requires to get up to that speed on one side of the engraving and slow down to a stop on the other side, so relatively narrow engraved patterns will cause the laser to spend most of its time not engraving.
The Overscanning doc has useful pictures and a detailed explanation of how going faster may increase the overall job time:
It depends on how you define “better quality”, because the only thing the laser does is heat the material enough to damage it. The amount of damage depends on both the power delivered by the beam and the time spent delivering it to any one location: more power for a shorter time will produce approximately the same damage as less power for a longer time.
The Engraving doc goes into more detail the factors affecting the result:
A 120 W laser may be too powerful for some materials, because the laser tube will not fire reliably below about 15% of its maximum current. Depending on the material, that power level may require a very high speed to produce the effect you want, but the machine may not be capable of reaching that speed.
Everything is a tradeoff among many factors: welcome to the wonderful world of lasers! 
2 Likes
This is from the preview screen. Both of these have the same 50mmx100mm box in them. Both are using 8000mm/s^2 acceleration values. Enabling show transversal moves shows the head positions or travel in red. The laser head is moving, but not lasing.
On the right is a 500mm/s operation, the overscan is in red. Notice the estimated time (green).
Increasing to 1000mm/s overscan actually goes outside of the defined work area, which is shown by the light green box within the preview screen. The Ruida would call this something like slop error. However you can actually see that the head spends much more time slowing down, changing directions and getting back up to speed than it does actually doing the job.
Here one that is more of a job that we typically do. I’m scanning this, on the right is 6000mm/s^2 and the left is an acceleration value of 40000mm/s^2. Notice the job times.
If you want to speed up a job, figure out how to increase your acceleration value. It also shows why speed isn’t everything.
Make sense?
Preview simulates how the machine is expected to run the job. So it only shows where it’s lasing. It has no clue as to the material.
Preview is your friend, learn to use it before a run, it will save you time and material.
1 Like
This was great, thank you for sharing!
Awesome, thank you for the info!
Agreed, I have a 100 watt laser, and my laser won’t fire below 12%. Hard to produce quality photo vengeavings…but great for what I do the most of, inlays and acrylic.
1 Like