[bpoulin]

I am wondering about optics, how is it measured. And what optics are best for just engraving? Currently the smallest spot I can get is about .33mm which equates to 238dpi I would like to be above 500dpi obviously more is better.

[Tweakie]

The spot size is related to focal distance, with a 50mm FD lens you should be able to achieve a spot size of 0.05mm.

Tweakie.

[bpoulin]

The MFG contacted me last night, they say it has a 2.5" lens in it, and they have 2.0" lenses available. So the 2.0 is as close to 50mm I can get, They say they don't have any lenses that go below 2.0 but I've heard of people on here talking about 1.5" lenses, are they aftermarket? And where could I get one?

[Tweakie]

The MFG contacted me last night, they say it has a 2.5" lens in it, and they have 2.0" lenses available. So the 2.0 is as close to 50mm I can get, They say they don't have any lenses that go below 2.0 but I've heard of people on here talking about 1.5" lenses, are they aftermarket? And where could I get one?

My lenses came from Israel perhaps eBay is the place to look.

Tweakie.

[bpoulin]

I found one supplier selling a 25mm lens AKA 1" lens. I'm wondering if this would just be overkill? I know the machine is capable of 1000 positions per inch, therefore 1000dpi but at what point is it just overkill? What is the max viable DPI for a 1.5" or 38mm lens?

[Tweakie]

Sometimes they get confused between focal distance and lens diameter (perhaps its the language translation) but I would think that a 25mm FD would be quite difficult to use, especially if you have a coaxial air assist nozzle. The down side of short FD is that the depth of field is reduced so it is good for engraving but limited to thickness of material when cutting. Isn't everything just a compromise ?

Last year, Universal introduced an upgrade mod to their machines of a beam expander, collimator, and short FD lens which does produce quite stunning results High Power Density Focusing Optics? (HPDFO) - Universal Laser Systems

Tweakie.