Laser Cutter Speed vs Power – Find the Perfect Settings

We’ve all been there, cutting over the same lines, trying to define what laser cutter speed vs power setting we should use. After 50 separate cuts, you give up in frustration.

While it may seem simple on the surface, speed and power settings in a laser cutter can be hard to handle without experience, and how the two are balanced can have a great effect on your cut.

So those of us in the dark are wasting material testing to no avail.

The solution is actually incredibly easy to find and once you understand the basics, you’ll be wondering why you didn’t get it before.

[tds_council]Are they really that different? Can’t you just lower one or the other?

Absolutely not. I used to think that the two settings were interchangeable. But after lots of testing, I realized that changing either one will produce different effects. At the same time, you must use them together, as they go hand in hand.[/tds_council]

Power

The power level directly controls the amount of energy in the laser. As power increases, the energy in the laser increases.

The amount of energy needed to penetrate will vary between materials and their thickness.

Since the laser cuts in a thin conical shape, more power will result in more perpendicular walls and a deeper cut, but will also mean more material removed.

High energy could also make more smoke and charred edges.

So, power is a necessity to reach a required cutting depth, but it is quite destructive to our materials. How can we balance this to make clear edges and less smoke?

This is where speed comes in.

[tds_note]Summary

More power = deeper cut = wide edges

Less power = shallower cut = straighter edges[/tds_note]

Speed

The setting changes the speed that the laser carriage will move.

The key to speed is that the longer the energy is exposed to a part, the more energy it will receive. Remember that high exposure to energy could result in smoke and charred edges.

Therefore, we use speed to control the length of time energy is on a point, thereby reducing the exposure to energy, yet still having the required amount to make a cut and avoid flames.

Increasing speed will also make the time of your project quicker. However, too much speed limits energy exposure and could make your cut too shallow.

Keep in mind that the carriage has to accelerate and decelerate, so the chosen speed may not reflect on the edges of the cut.

[tds_note]Summary

Higher speed = faster cutting = shallower cut

Lower speed = slower cutting = deeper cut

Going too fast or too slow could result in undesirable edges.[/tds_note]

The Delicate Balance Between Speed and Power

As you can tell, there is a delicate balance between speed and power. But don’t worry, most of the time we’re looking for more of an acceptable balance, rather than perfect.

With power and speed levels ranging from 1-100, there are 9801 different combinations to use, with one that is optimal and a hundred more that are acceptable.

Getting within the range of an acceptable balance isn’t as hard as you think.

How to Find the Perfect Speed vs Power Setting

There is a quick test you can use to find the best speed and power settings for your cut.

You can find many charts online with predetermined settings, such as this one. While they can be useful, you should still test it out for yourself.

Whenever you use new materials, you should use this test on it because every laser cutter will react differently. That’s why in my guide on Laser Cutting Materials, I intentionally excluded specific speed and power settings.

How to Make the Speed vs Power Matrix

The best thing about this test is that you only have to set up most of it once!

You will need:

• Laser cutter (of course)
• Scrap piece of your chosen material
• Patience and determination

[tds_warning]Make sure to keep your results! Cut out the grid and keep it somewhere so you can always refer back to it![/tds_warning]

Laser Cutting Matrix Test

To penetrate the material entirely and cleanly, we need to have enough power to cut deep and enough time for the laser to penetrate.

The Method:

1. Determine how accurate you would like to be. This will determine how many combinations you will test (100 combinations are usually tested to find an acceptable zone).

In your drawing program, create a grid of unfilled boxes (e.g. 10×10 for 100 combinations) making sure to leave some space in between them. You could get this done within 8 copies and pastes.

2. Name the x-axis ‘speed’, and write the percentage tested on each column. Name the y-axis ‘power’, and match each row with the percentage tested.

3. In your laser cutting program, assign each colour a different setting. Start with low power and low speed.

4. Assign the outline of each square in your matrix according to colour.

5. Begin cutting!

Results

When the test is over look for the squares that are completely cut, with straight edges and no char.

If you want to test even further, you can test in the range of the best results with smaller increments.

For instance, if 50%/60% power and 50%/60% speed were the best, then you can test the numbers in between that (like 51% then 52%, etc.).

If you are unable to produce your desired edge quality, then you might have to look into some other parameters like the number of pass-throughs.

Laser Engraving Matrix Test

To find your desired darkness, we need to use the right amount of power and move fast enough to ensure that we only affect the surface.

The test is basically the same as the laser cutting one but using the grayscale method instead.

The Method:

1. Create the same grid as the method above, except this time, the squares will have to be outlined and filled in different shades of black. They can also be much closer.

Instead of making one yourself, I would suggest downloading one from Thingiverse.

2. Start with high cutting speed and begin engraving.

Results

The different shades of gray will output various engraving power in the laser. If a box is 50% gray, then a 50% output will be used.

Look for things such as how many different levels you have and how they transition.

If all of your squares are too dark at high speed, then you can try lowering the speed until you find your desired engraving. Alternatively, you could adjust your laser’s z-axis for darker results.

Conclusion

Speed and power have a delicate balance and there are only a handful of combinations of both that will produce the best results. As you can see, finding the right balance really isn’t that hard and all it requires is a little trial and error.

Well, there you have it! A starting guide on how to find the right speed vs power settings for your laser cutter.

This is only scratching the surface of what you can do and there are many more parameters to think about such as dpi, passes, Hz and more.

As always, feel free to let us know if you have any dandy tricks to find the right speed vs power settings for your laser cutter in the comments below!