Bad lense on my laser?

Question for anyone out there who is running a laser on their mpcnc. After several weeks and LOTS of help (and tests) I am close to getting this finished to a point of super usefulness. using laseretch (and learning how to manipulate the sizing, special thanks to “some old guy coding” for a excellent explanation) I am able to get a decent burn from my laser and solid engraving, but never get a good burn when trying to engrave shades such as a picture. With help before I have eliminated lots of problems that i had including a bad ramps board.


The only thing i see left is my lense. When I look at other videos their laser beams seem focused and small. When I look at mine the “beam” is small and concentrated but there seems to be LOTS of bleeding of the blue light in a large circle around the output. Does anyone else have this on theirs? I am wondering if now I need to replace my lense. I am contemplating replacing it with one from Jtech.


Thoughts and thanks

What laser, what lens? What is your focal length?

Is the lens seated in properly? They do all bleed a bit but I don’t think mine looks like that.

It is a generic 3W laser from china. I did some troubleshooting using the jtech photonics website and was able to determine it is a high efficiency lens which focusing around 2in. and I replaced the generic driver with a Wayle(copy) driver. When I first mounted it and used it I had completely different results (much more powerful) then after playing with it it doesn’t seem to be able to focus as well. It woudl completely make sense to think that the lense could be off center. I get about a 2in circle of blue around my focal point. I have not been able to find any tutorials on seating the lens in the housing. Any thoughts on how to check this?

You changed the driver and got more power? Be careful you can decrease the diode life drastically, I was under the assumption those shipped pretty overpowered as it is. Did you calibrate the driver?

If you are getting burning you are probably fine, use the focusing script and use it some more. All of these diodes bleed light. I have no idea if yours is any better or worse than other as I do not have that one, but you are getting burning so I suspect it is actually fine.

You say you are having a problem getting “shades”, that is a low power gcode issue, not a lens issue.

Yes the driver is calibrated. I meant that when I first got the laser it seemed to have more power before i played with focusing the lens. I can use laseretch and get a nice burn on the wood, but that is only black and white. No matter how many adjustments I make to image2gcode it basically comes out blank. When I use the it comes out better but still not as dark and detailed as i would like. Is there any sample working gcode files that I could test with?



You might find this thread relevant with Image2Gcode

I think there is a bug in the code such that if the image is too black then it gcodes it M106 S0. I’m still teaching myself C# and visual studio so haven’t got into the code yet. The fix which solved Wes Murray’s and my images was to increase the gamma. You don’t have to etch to test just open the gcode file in a text editor and search for “M106 S0” to see what the program is doing.