Newbie where to start dot test?

Newbie here, please be patient. Just added a chinese diode laser to my homemade cnc router two days ago. I am pretty comfortable with the machine…not the laser nor the software. I have the laser attached connected to my trial lb software and can control x,y, and z axis of laser along with the power of laser with blackbox. I have burned a few images, but none that I would say I was proud of. I have lots of questions.
Here are a few:

  1. Focusing the laser should be priority number 1? I can move z axis up and down this is how I am focusing laser. (I assume this is correct). In order to focus, I should set the laser at a distance from the “stock” in which i get the smallest “dot” on the material??

  2. I am reading about a dot test in order to see what size dot my laser can achieve. Should this be step two? Can someone attach the file of the dot test in inches if possible. I am an inches guy… I know how to change in the lb software but my simple mind is hard to understand mm…

  3. I use fusion 360 for my cnc router. What file type should I be sending to lb to burn on material?

  4. I see some lasers come with an enclosure around the acutual beam to shield eyes from laser. Mine doesn’t have this. I just have goggles. Can I build or buy an enclosure to go around mine? What material is this? where do you get it?

  5. My laser has cut off twice during a burn for unknown reasons. Why? Is there a way to resume job from where it cut off?

I have lots more questions, but I figured these were a place to start. Any and all help is appreciated!


A very good learning resource for any type of laser is Russ Sadler from the UK who has a youtube channel: sabarmultimedia. Over 150 videos to learn from. There is another resource: There is a collection of files that Russ created for laser set ups. One in particular is his dot test file. Forum>Resources>Russ Sadler’s Adventures> Files From Russ. You will need to create a log in to download his files. I think the dot size test file is this: dotSize.bmp.

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