There was a previous thread that expired and closed. Has anyone resolved this issue?
I cannot focus the laser to a dot. See the attached image. No matter how many times I fine tune it I cannot get a thin line on the x axis.
I wouldn’t expect it from a 2.8 watt diode, but it looks very much like a “standard laser beam” which is actually a tiny bit oblong square.
With the cheap Chinese diode laser you can sometimes offset this effect by turning the diode inside the house so the distribution is equal to X and Y. But as I said I would not expect it from a 2.8 diode, so maybe I’m not right . (my 5.5 watt diode has it too but not even half as bad)
Think I figured it out based on info provided on the jtechphotonics focusing 101 page. A diode beam is in the shape of an hour glass. The focal point is located in the center of the hour glass shape (where the sand will pass through). The distance the substrate is from the laser is important. I provided a distance of 1.5" between the underside of the heat sync and the substrate; then focussed the laser. Success! A dot rather than the oblong shape I was getting in the previous post. The laser is roughly a 7w so compared to my other 2.8w the dot is larger. Will experiment more to see if I can decrease the size of the dot.
That being said the dot size isn’t too bad… this image is a grid where the lines are 1mm apart.
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