Lens quality, $20 3" v whatever 2" came with my LS900

[Kev Williams]

total goof.. .my bad... more later

[Bert Kemp]

thats right just leave us hangin https://s.yimg.com/ok/u/assets/img/emoticons/emo30.gif

[Kev Williams]

Well, I posted up an experiment that showed that a $20 lens was incredibly bad compared to my 'good' LS900 lens...

I was using a 3" lens in an upside-down holder from the Triumph, so to get an 'accurate' focus distance I did a ramp test to find the best focus...

Then I did some test engraving, and the engraving quality was simply not very good compared to the good lens.

After I posted up the results, complete with pics, I decided to do some focus tweaking and see if I could better the results...

Turns out my ramp test was bogus, why I don't know, but in the end the ramp test best focus area was almost a full 1/4" from the ACTUAL best focus area! After some final tweaks, I found the el-cheap 3" lens engraved just as good as the expensive 2" lens. The ONLY difference was the engraving was a snick "thicker", which is exactly what I wanted! Reason being, the LS900's beam spot is substantially smaller than any of my other machine's beam spot, and I need to be able to have the LS900 more closely match the engraving the Triumph and the GCC does. And the 3" lens thickens up the engraving perfectly!

- my original post was a firm condemnation of the cheap lens, when the problem was me, not the lens! :D -- so, that's what happened! ;)

[Bert Kemp]

So the ramp test gave you a focus distance which was with a thin kerf but gave a lousy engraving you then went further away or closer by a 1/4 inch and now it engrave OK , is this right.So technically your out of focus by a 1/4 inch