K40 materials setting

This has been a very stressful learning curve. I can’t seem to pin point my settings for fine details on wood or any materials on Lightburn. I have a k40 with cohesion3d. I try the power scale got it close try powering up and up spend up and down nothing yet.
Settings that got it closes is 3.91 speed 70% power also went up to 5.91 speed and 75% power but details aren’t clean HELP please…

Wood is a hard material to work with because of the inherent, intrinsic variability of the material.

That said, one of the hardest things to get right when doing engraving on a K40 is the focus - if you want good results you’ll have to play with the focal distance. There are a couple ways to deal with this - an adjustable Z table where you can move the object itself up and down in relation to the laser head, an adjustable laser head where you can move the lens in relation to the fixed table, or a set of lenses that have different focal lengths (among other things). The lenses are fairly expensive and fragile, so unless you have a really good reason to change them I wouldn’t suggest that right away. Z tables for a K40 are a decent choice, but are also a bit on the expensive side and some are of dodgy quality. So, that leaves an adjustable laser head - fortunately these are inexpensive and easy to install, so I recommend you start here.

Another thing that can help tremendously is adding an air assist to the nozzle if your laser doesn’t already have one. Most adjustable laser heads come with this feature, too.

Now, when you do have the ability to focus your beam spot, you’ll want to try out various settings and see what gives you the best results. I personally try to focus the beam as best as possible, but others say getting the spot ever-so-slightly out of focus gives them better results. If it’s way out of focus it’ll just look messy. But also keep in mind that wood is a very variable, and often times difficult-to-work-with material. There’s also a lot of variability between machines, so even if I give you the settings I use with my machine there’s no saying they’ll give you anywhere near the same results. It’s unfortunately, a time-consuming trial-and-error process we all have to work through as we become more familiar with our machines and the materials with which we work.

Good luck!


Thanks I do have the Lightburn camera. It’s just pin pointing the power setting and speed before all the upgrades I use k40 wispher and was very easy thought with all the upgrades it would be cake but it seem much more complicated. I’m hoping it’s just a learning curve after investing

To add to the great points Loather made, it also depends on what type of engraving you are doing and the substrate you are working with.

For the focal distance mentioned, try doing a ramp test to determine your focal point for cutting or engraving. It sounds like you have already done a power scale test to try to determine what settings give you the best engraving output. It is definitely a trial and error process.

Review your speed and power settings. Try increasing the max power if it is below 100% (which equates to pure black in your design/image). Setting this to a lower value will decrease the power of the laser when engraving absolute black. Try increasing the minimum power (which equates to pure white in your design/image). Increasing this value beyond your laser’s firing threshold will allow the laser to fire for absolute white.

If you are getting “charred” results, try lowering your power and increasing your speed. If the results are too light, try increasing your power and lowering your speed. As he mentioned, air assist is a great help.

For image engraving, review and adjust your DPI. I recommend reading this topic to get a better understanding of how it works, as well as the included link at the bottom which has links to other resources: https://forum.lightburnsoftware.com/t/image-engraving-guidelines/12913

I also scoured forum and social media groups to get a general idea of setting ranges for what other people were using for different materials as a starting point. Then I altered my settings, based on my understanding of how my machine worked after running a multitude of tests. It takes time, a little finesse, a lot of patience, and trial runs to get it just right for each scenario. Good luck!