So after a very frustrating start to "lasering" this weekend i finally discovered a fundamental thing and i have a much better understanding of the different issues i have been experiencing lately. Basically what has been happening is i will do some smaller test cuts on the left side of the table. It looks amazing, no burning on top, cuts cleanly thru on the bottom. So i go to do a full table cut and the right half of the table looks like garbage on top, tons of shadow burns around the cuts, and the bottom almost doesn't even cut thru in most spots on the right. What i realized pretty quick was the wood was not the same thickness or was raised slightly and so i couldn't set my cutting depth the same for the whole table.
Problem number two is that omtech sold me this table with the specific feature of "dual passthrough doors" so you can put pieces in larger than the cutting area. Well the problem with that is the closest i can get the materials to the nozzle is about 112mm. But to get a good cut it needs to be about 8mm at most. So impossible basically in current setup. Yeah i sent some nasty grams to tech support. And they have zero answers for me.
I dont remember the exact google/youtube search that led me to the answer to this but basically what it comes down to is that i have a specialized lens for engraving. Here is a nice pdf that kind of goes thru the different types of lenses, ill kind of sum it up here:
Basically there are different lenses for different tasks. They are rated in inches. The distance (focal distance) from the lens to the cutting material. On the one side you have 1.5 inches and on the other extreme you have 5 inches. Now there are others but these are the major ones.
Here's the major point that i came to while reading this pdf and watching a bunch of comparison videos. The closer the focal length, the smaller the depth of focus. So in the case of the 1.5" lens, that i have, the depth of focus, the area that it cuts, is tiny. This is why the wood raising up even a couple of mm would change how it was cutting. Im trying to cut with an engraving lens. As you go up larger in focal length, that depth of focus gets significantly larger. The 2.5" for instance is good for up to 5/8" thickness.
And now i know that with a 4" lens i can actually use the passthrough doors on my table. Basically omtech doesnt know how to use the tables they sell. I would buy from them again, but now my expectations have been set.
So trying to teach myself this on my own i am learning the hard way. But it looks like a lot of guys just have a full range of lens' so they can switch them out depending on the task. I have a 2.5" on order from amazon, they are like $22. I tested it this morning and it takes less than a minute to drop the old parts out and put the new one in.
I am also assuming units like glowforges have a more general use lens like a 2.5 as it can be used for up to 500dpi engraving and nice cutting up to 1/2" so this may be the lens i just keep in it from now on. Ill post once i get it installed.
As far as cool stuff i got to once i got over that slight bump, i got my lightburn camera installed, its pretty slick. Lets me place my designs on material using the camera, glowforge style:
And played around with some 1/8 acrylic this weekend as well. needs some leds.
