Diode Laser Astigmatism? Blurry Vertical Lines, Sharp Horizontal Lines – AtomStack A24 Pro

[DCX (Daniel)]

Hey everyone,

I recently picked up an AtomStack A24 Pro and ran into a concerning issue right out of the box. During a quick test engraving, I noticed something strange: vertical lines were coming out noticeably blurry and wide, while horizontal lines were sharp and clean.

To investigate further, I engraved multiple 1cm x 1cm squares at various speeds and power settings. The results were consistent — vertical lines always appeared fuzzy and significantly thicker than their horizontal counterparts.

When I tried cutting a square in 3mm plywood, the issue became even more obvious. Horizontal cuts went through cleanly at 90% power / 650 mm/min, but to get the vertical cuts to match, I had to slow it down to 90% power / 350 mm/min — a big difference.

I ruled out mechanical issues and checked the lens — it’s crystal clear, no dirt or damage. That’s when I decided to examine the laser spot itself.

After a few attempts on different materials, I got the clearest laser spots on thermal receipt paper. I pulsed the laser manually at low power (3–6%) and photographed the spots using a 1:1 macro lens. The photos confirmed my suspicion: the laser beam is visibly deformed — more of a long oval than a tight point — which perfectly explains the engraving and cutting anomalies I’ve been seeing.

From what I can tell, this is a textbook case of diode laser astigmatism.

Unfortunately, when I contacted AtomStack support, they initially seemed helpful, but in their most recent message, they claimed this behavior is “normal.” I’ve since asked to escalate the issue and I’m still waiting for their response.

Why I’m Posting This:

To get feedback from the community — I know many of you have far more experience than I do, and I’d appreciate any insights or confirmation on my diagnosis.

To help others — I spent hours searching online for similar symptoms and found very little. Hopefully, this thread helps someone else who’s troubleshooting a similar issue.

To add visibility — Having this issue documented and discussed publicly could support my case if AtomStack continues to push back on a warranty replacement.

I’ve attached the images below for reference. Any thoughts, advice, or suggestions would be greatly appreciated.

Thanks in advance!

[Dskall (D Kallenberger)]

Diodes won’t give perfect cuts on both axis, and the higher the power the worse it gets, but this looks excessive to me.

[Bugeyz (Peter)]

Diode lasers do not produce a round or symmetrical beam; they produce an elliptical. This is due to asymmetrical nature of the PN junction in the diode itself. My laser produces a beam that is approximately 0.1mm by 0.08mm in shape. So along one axis it get I get narrow lines and along the other I get wider lines. Diagonals are noticeable as well. But what you displayed seems excessive as another commenter mentioned.

[DCX (Daniel)]

@Bugeyz @Dskall Thank you for your comments — that’s exactly my point. I know that diode lasers don’t have a perfectly square spot and that it’s normal for the beam to be slightly elliptical. But in this case, the distortion seems way too extreme and it’s very noticeable, especially when engraving.

When it comes to cutting, the difference creates a big problem in my view. There’s almost a 50% difference in cutting speed between vertical and horizontal lines, which makes it practically impossible to get clean cuts without excessive charring. One axis always ends up way too overpowered.

I’ve added two more images to show what I mean — one of the square and another of the laser spot both next to a ruler with 0.5mm markings. Based on the specs of the laser, the height of the spot should be around 0.08mm, but the width looks to be about 5 to 6 times larger than the height, so somewhere between 0.40mm and 0.48mm. That lines up with what is shown in the photos and is way off the specification of 0.06 x 0.08 mm for this laser.

[misken (Melvin)]

Point the laser at a wall and take a picture. Then you can better see the individual diodes.

[DCX (Daniel)]

@misken Thank you.

This is what I get pointing the laser at a wall about 2 meters away, at 3% power, in a dark room. Camera right behind the laser.

[misken (Melvin)]

That doesn’t actually look so bad. It depends one the beam optics if those two spots form a (relatively square) combined beam or if they are overlain in the focus spot. In that case, the beam is very rectangular. But still, the main spot looks ok. You can see some pictures of other modules that I have taken here: Guide to mechanical adjustments and maintenance (for comparison).

[DCX (Daniel)]

The previous photo I took was at 2m. But at 1m the spot still has the same shape as before (nothing like the ones in your photos). Then I decided to photograph it at shorter distances, and here is what I found.. The shape started changing in a way I did not expect, but the final photo at 2.5cm matches exactly the problem I’m describing, as well as the macro photo of the laser spot on thermal paper. I also noticed that my previous photo at 2m did not have the correct orientation. Now all the photos are orientated to the same axis.

[misken (Melvin)]

To me, that looks like the optics is not aligned correctly, the spots that should be on top of each other are next to each other. I don’t have a similar module to compare it to, but you might reach out to the manufacturer to get a replacement.
You could try to do a focus test and check if the focus is just at a different distance than advertised..

[DCX (Daniel)]

Unfortunately, AtomStack continues to deny there’s anything wrong with the laser. For nearly a month now, they’ve insisted that everything is “normal”—despite the clear evidence to the contrary.

In their latest response today, they told me that if I’m not satisfied, I can return the laser for a refund. But here’s the catch: I’d have to ship a large, heavy package across Europe to their warehouse in Germany, entirely at my own expense.

This seems to be the core of their strategy: avoid acknowledging any fault with the product so they’re not liable for return shipping or replacement costs. They’re framing this as a case of me simply “not liking” the product, rather than admitting there’s a defect. That way, they don’t lose any money, while I’m stuck with the hassle and cost.

I’ve now opened a dispute with my bank and am in the process of filing a formal complaint with the EU consumer protection agency.

If there are any new developments, I’ll continue to update this thread.

Also, I’ve added a few new photos below (taken with a different lens this time) for anyone interested.

[amos77 (Ami)]

I have a similar problem, does anyone have an A24 Pro that behaves differently? Maybe it is a design flaw. The laser seems to me much weaker than advertise.

I have received replacement lenses from atomstack, which did not help.

here is my beam on a wall @2 Meters / 2% power

and the cut 10000 mm/m / 80%

[misken (Melvin)]

That looks like a faulty optics as well.

[amos77 (Ami)]

does anyone have a picture of a “proper” A24 Pro beam?

[bernd.dk (Bernd)]

@DCX

They’re framing this as a case of me simply “not liking” the product, rather than admitting there’s a defect.

This sounds like very poor customer service and damage control from AtomStack. Most with some diode laser experience will attest that the focus shown by your laser is not reasonably usable. Not being cooperative in troubleshooting and replacing a defective product ultimately backfires on the company.