Laser Engraving Problems

I own several desktop diode lasers. And I frequently try to get my hands on as many laser engravers as I can. I belong to several online laser forums on Facebook, Reddit, and I follow most of the laser manufacturers on Instagram. Frequently I am stunned and amazed at the level of laser engraving problems that I read about daily in those forums.

I got my first desktop diode laser in 2020 which is about the time they hit the scene. Since that time I have probably owned 12 or 15 lasers. I get them, play with them, and blog about them. Then I sell them or give them away.

Strangely enough, I have just not ever experienced any of these problems I read about. Or it is maybe safer to say that I’ve only seen them once or twice.

Some of the more common problems that I want to discuss are:

Laser stops engraving before finished
Laser is weak
Laser stops firing
Laser only moves back and forth or front to back

Issues

There are a lot more issues than those listed, but I see those all the time. And then I can’t help but wonder, “Why do these things never happen to me?” And I think the answer to that is twofold.

First, I spent a career as an electronics troubleshooter in DOD. Second is that I have owned 2 and 3 axis machines for a long time before desktop lasers became a thing. A laser is almost no different than an inkjet printer. The only difference is that instead of laying down ink, it lays down a beam of light instead. The X and Y movements are the same. We call that a “plotter”. If your laser stops engraving before the job is done it is easy to troubleshoot.

Here is the important part. Your laser Console usually outputs what is wrong. Your average, new laser user doesn’t bother to read the output in the console. Once I helped someone who constantly had a laser job stop. He tried it 15 times and ruined 15 pieces of material at least. He ran a demonstration, it stopped, and the console said the flame alarm halted the job. The wood he was burning was throwing up a little flame and setting off the alarm.

Another time the console set off a movement alarm. The person I was helping was engraving at a really fast speed. The laser was unsecured, just sitting on a table. The fast laser movements were jostling the machine and setting off the alarm.

The moral to the story: READ THE CONSOLE WHEN SOMETHING GOES WRONG.

More Stoppage Issues

Your laser probably uses GRBL to generate gcode. Gcode tells the laser how to move and how fast to move. The sequence is COMPUTER > LASER. In that path may be a USB Controller, a USB cable, and an SD card on the laser.

Your computer could be a dog and have programs gobbling CPU cycles and RAM which corrupt your gcode streaming.
Your USB port could be timing out and going to sleep.
Your COM Port drivers (Windows) could be outdated and old as dirt.
Your USB cable could be crap.

Let’s break off my bullet list above here and talk about the last one. Your USB cable has 4 to 5 wires. 5v, Ground, Data +, and Data -. There might be a shield as well.

An unshielded cable can act as an antenna and pick up stray signals. It is easily possible to corrupt the Data stream in the + or – wires. It happens all the time. That is referred to as EMI or RFI or various other names.

Example

My xTool D1 Pro stopped on me a couple of times. My cheap ass aquarium air pump I used for air assist would quite literally corrupt the signal to my monitor (Mac Mini) when I plugged or unplugged the air assist. I could visibly see that corruption. When the laser stream stopped that was my first suspect. After plugging the air assist into another outlet or a portable power supply the signal corruption stopped and my laser has worked perfectly ever since. And that also fixed the monitor problem. That pump must have been spewing electromagnetic interference and the unshielded USB cable was picking that up.

So when you think of it in terms of getting that generated gcode CLEANLY from your computer to your laser motherboard you have to consider how it could get stopped or corrupted. THE PROBLEM IS RELATED TO THE STREAMING OF THAT GCODE DATA. Let me add another bullet to my list above.

Hardware failure. Your laser motherboard or SD card could quite simply be bad. I suppose you could apply that to the USB controller on your computer as well.

Laser Engraving Problems – Weak Laser

Your laser is an optical device. There are generally 2 pieces of glass in the path of a laser beam. A lens, and a protective glass. Both must be maintained with the OPTIMUM OF CLEANLINESS. You may read various recommendations of when to clean your optical glass but here is my recommendation: Clean it after every laser operation. Use 91% or better isopropyl alcohol and a microfiber cloth for cleaning optical grade glass.

That may sound excessive, and maybe it is. But you are looking at a guy who has owned a dozen lasers and never had a lens failure. And I’m a Laser OG from way back when in 2020.

Diode lasers, by nature also DEGRADE OVER TIME. Run your diode laser at 100% to do a Norton White Tile for 4 or 5 hours every day and down the road you are going to realize some degradation. The only cure for that is to replace the actual diode laser head. It is quite simply something to anticipate and plan for if you are in business and use your diode laser a lot.

Laser Engraver Problems – Laser Stops Firing

I see this one a lot. There are really only a couple of failure points here.

Motherboard failure
Cabling issue
Laser head failure

Back in the day with most laser manufacturers you could buy spare parts. I would always pick up a spare main board and a spare laser. Nowadays, if you can find a spare mainboard and a spare laser head it probably costs more than buying a back up machine. Manufacturers such as xTool will sell a kit which has an additional laser cable. Having two machines is always highly recommended by me, especially if you are in business. Having two machines could isolate this problem easily. Just swap the laser head, and if needed the cable.

Laser Not Moving In All Directions

Each axis of movement has a motor. If your machine only moves backwards and forwards or right to left then one of the motors is not working. This could be from no signal or voltage reaching the motor. It could also be from an improperly installed cable. The motor could be bad although this is not going to be a common problem.

Final Thoughts

In troubleshooting you have to correctly assess what the actual defect is and consider what the possible solutions are for your laser engraving problems. No reason to clean the lens or grease the rails if the machine is only moving backwards and forwards. You need to be looking at a motor or cabling issue.

Dissect the problem and consider what components are actually affected.

Lastly, most problems are injected during assembly. Take your time when building your machine.