# Estimated conversion of power and speed settings from 5.5 watt to 20 watt

Is there a rough conversion to use as a starting point?

Thanks!

Dale

In round numbers, speed is proportional to laser power: double the power and double the speed to deposit about the same energy on the material.

That is totally inaccurate, but it’ll give you boundaries for the `Material Test` required for a better answer.

So, If my 20 watt machine is roughly 75% more powerful than a 5.5, would I then reduce both power and speed indicated for 5.5 by 75%?

The speed goes the other way. If you were using a 5 W laser at 1000 mm/min (and some power percentage), you can run a 10 W (*) laser at 2000 mm/min (with the same PWM).

Throttling the 10 W laser down to 5 W by halving the PWM and running at the same speed as before would work, but then there’s not much point to buying Moah Powah.

(*) Whatever. Honest power ratings seem very difficult to come by; when I see a seller rate the “laser diode power” using the machine’s total power supply consumption (including the steppers!) I hold my nose and walk the other way.

I’m sorry, I don’t think I’m being clear. I have a grid patter for my waste board, and it’s power and speed settings are for a 5.5 watt laser. I have a Sculpfun 30, 20 watt laser. How do I adjust the power an d speed settings on the more powerful laser?

Not sure what is a grid patter, but as suggested, you should make a Material Test (in Laser Tools) for your new laser. It will the most accurate answer to your questions, I think. (At the expense of some material.)

The slower you run the higher average power you get to the material at any given power setting.

If the machine is running 100mm/s@50% power, it’s theoretically the same as 200mm/s@100%.

Might help if you advised us of your speed and power setting for some project.

Half the information is difficult to give you any kind of formula or math relationship which is what you want.

As @PhiLho points out, the best way is using the materials test on scrap.

The issue is that the relationships between settings change for a few reasons. The most simple is that your 20W may actually be 18 and your 5.5W may be 6.3. That will impact any kind of calculations.

If you don’t have scrap to test on, it’s an issue and only experience can help you solve that.

If you do it and it’s too light, then just run the job again without moving anything. It should darken it and/or allow you to change parameters before you run it again.

I do this more than I’d like to with the fibre machine

Does that make sense?

Have you run a ramp test on the new laser…?

This also shows you the lasers depth of field.

I suggest you test it to ensure your proper focus point is where the factory thinks it is.

I would recommenced using the built in material test generator within Lightburn to get an idea of what the new laser is capable of. Not every setting is linear from laser to laser. I would run a series of test to form a baseline of speed vs power. This is a great tool to get to know your laser and keep a handy chart of usable settings.

I just watched the Lightburn first project again. On any given project are the speed and power settings shown in the cuts and layers window the values recommended by Lightburn specific for the machine I’ve listed?

There are NO settings anywhere available that perfectly fits your machine. You need to test every single time with your machine and your material what settings you like most. There is no other way to do it. You can get starting points from other users but no perfect values.

I read the settings guide you sent yesterday, answered a lot of questions. I understand what you’re saying about material testing. But, where do the settings that are listed from a given pattern come from, what do they mean?

By default, LightBurn sets 30 layers with defaults settings (and 2 frame layers), and when you import a SVG with lines of various colors, tries to match these colors to set a layer to them, so it defines default values from these layers.
These values are probably commonly used settings, perhaps related to the type of laser you have (at least they make sense for my 10 W diode laser), but they are just suggestions, and it is most probable you have to adjust the settings of each layer anyway.
One kind of line, you prefer to engrave rather than cut, for line text, you might want to fill it instead of using line, and so on.
LB provides suggestions, but you have to adjust them.

Also note there are two modes: either it always keeps these defaults settings, or it keeps the adjusted settings (the changed value for each layer) on the next project. The latter might be useful if you always do the same kind of project (always the same material, for example). You can set your own defaults settings, this way.

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