Eh no worries. I’m completely open to correction, and would love to know exactly what the root cause of this is, because as I mentioned prior, the patterning is somewhat uncommon for this issue, but shows most of the symptoms.
My only goal here is to share helpful information, based on my and others documented experiences.
The image is vector engraved… I tried tonight using the defocus mode and it was a vast improvement but still showed some lines. I have attached two photos, one raw and the other adjusted to exaggerate the lines a bit to make it easier to see in the upper right corner. ( its more obvious to the human eye) It’s not a perfect engrave but at least passable. Still need some sort of more permanent solution though.
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What you’re seeing is completely normal, and it’s neither consistent nor predictable.
Acrylic is a very “precise” material when it comes to engraving, which unfortunately highlights the fact that the laser doesn’t produce perfectly consistent power, and the motion control can have very minor “steps”. It often shows up as “banding” in the image, similar to your first and last pics. As you found, you can change the focus height to smooth it out a little. I’ve never chased it down long enough to verify, but I suspect a second defocused pass might help even more, which of course takes time.
Here’s an example at different power settings. Note it occurs in both horizontal and vertical directions. These are all solid vector engraves.
Thanks eflyguy, so it it just something we have to live with? I have done quite a few engraves with acrylic and have not had this problem until recently. It was never perfect but now its significantly more noticeable to where i don’t want to ship these items to paying customers because it just doesn’t look good. It’s a bummer if it’s “normal” but i guess i have just been lucky up to this point?
Did you try rasterizing it? Or rotating it once to see what happens?
Hi Jules, I totally misread your earlier comment. I thought rasterizing it was a cause of it. I have not tried them yet but will certainly do that next time. Going out of town for a few days so i’ll report back late next week. Thanks for your help.
No problem. Hope that works, it’s done it for me a time or two. 
Thank you so much for posting to the forum. I appreciate you providing such great detail to outline the behavior you are seeing.
As @eflyguy pointed out, this particular result is due to how Acrylic material behaves during engraving with your Glowforge. Defocusing in a second pass can sometimes provide better results, but it can be difficult to replicate the same perfection depending on the design and speed utilized during the print. If the trouble was hardware related, you would see the same consistency during engraves on alternant materials and additional print types (such as cutting or scoring).
@Jules also provided some great additional steps to help limit this behavior by rasterizing the design or changing the position of the material in the bed (rotating). Combining these two particular troubleshooting steps may help you derive more consistent results in your prints.
I also noticed that you have emailed us directly about this trouble, but I wanted to keep this thread open instead, so that the community can provide additional insight on helping you perfect your projects, and derive the best results for your customers!
I’ll move this particular thread to Everything Else, so that the discussion can continue. I’ll close the direct email ticket, but if you run into any more trouble, please don’t hesitate to reach out. We’re here to help 
When rasterizing, go to a png as a jpg will produce artifacts that are a whole new set of problems.
A helpful way to think about this is that if you look under a microscope, each raster line on the acrylic looks like a furrow:
The laser carves a tiny trail, with hills of melted plastic landing on either side. That can lead to unusual interference effects when one raised area lands on another.
If you’re ever near a microscope, looking at engraved acrylic is amazing. Like something from space!
I keep one on my desk, I’ll have to check this out.
Btw if you guys don’t keep one on your desk you are missing out. Here’s a really inexpensive one.
You’ll be surprised how often you reach for it.
Here’s a 0.2x0.1" piece engraved from a 100-0% gradient using custom “vary power” setting @ 270 LPI on PG medium black acrylic. 100% blows straight thru, so you’re looking at an engrave that results in a “wedge” of material.
I used 270 LPI because that’s the default SD Graphic resolution for that material. You can count the 27 “furrows” on the lighter engraved side.
I understand that but wouldn’t it be more random instead of consistent in a few areas? Why would some areas be very smooth and then some area have many distinctive lines?
This. Exactly this. I engrave all day with 0 issues in my engraves. If I had random lines popping up in my engrave all of the sudden I would be very upset. It’s not normal, well… Ill say it SHOULDNT be normal
A device that is supposed to be as precise as a laser, should have almost exactly the same output every single time. The fact that you are getting random aberrations in different attemps at the same print means something isnt working as it should.
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