I received a K40 5 days ago, purchased for a whopping $740 shipped. I did zero research prior, and have never used, witnesses someone use, or been around a laser cutter prior. You could say I didn't know a thing about them. Go ahead and yell if you notice i'm doing something wrong.
I have quite a bit of experience with the machine now, as well as the well designed Moshidraw software, but have a few questions.
Heres the machine I received... It's been a bit modified to increase the cuttable area, as well as work out better for my application. I don't have any interior shots of how it came new, but I assume most are familiar with it.
1) I'm making files in Illustrator CS5, saving as uncompressed 10 .ai's, importing into CorelDraw 11, exporting as HPGL, and sending to the cutter via Moshidraw. Most small circles are cut twice, larger circles and squares are not? Why? Is there any better way to do this? 95% of the time I will be cutting. Is NewlySeal/NeawlyDraw entirely useless as well? It was supposed to be included, I think, but I didn't get it.
2) There was a broken piece of glass in the laser tube, is that an issue?
3) Would a 100mm (4 Inch) lens work out better for cutting, even if the materials are not that thick? Most things will be .1-.25". Just get the cheapest 18mm 100mm CO2 lens on eBay and drop it in?
4) Is there any good way to adjust the height of the work to easily focus the beam? I've just been dropping things down and cutting, and it works for the most part.
5) All edges are not cut very vertical. This is actually better on thicker materials, but fairly bad on thinner ones, is this from the laser being out of focus? Would a 4" focal length lens help this, by making focus less critical? The bottom of the cut is narrower than the top, and the 'edge' formed always points away from the piece. The sides are always 'pyramid' shaped on 1/16 - 1/8" acrylic. Its barely noticeable on the 1/4" acrylic.
6) I've basically been using 10mA for everything, since above that isn't really helping. As low as I can get it to reliably fire is about 4mA, 5mA works best. That burns quite deep into acrylic engraving at 45mm/s with that power. No way to improve this? Nothing wrong with running 10mA all day?
7) Anything I should know about these units? It's basically just a cheap unit to screw around with. If it works out well, it will be replaced with something more serious.