NEJE JZ-5 Laser artifacts - looking for suggestions

[slow_rider]

I've bought this cheap laser engraver from GearBest https://www.gearbest.com/3d-printers-3d-printer-kits/pp_276279.html
The spec. claim 0.5W laser. The control software does not allow any control over power to the laser diode, only exposure time.
Long story short, I've been experimenting with "melting" laser printer toner onto surfaces to mark them and I am getting results all over the place, see pictures below. In most cases I'm getting these dots at the edge of the laser travel, in some cases I don't. It looks like the software is glitching however tech support is not available and in fact GearBest were nice enough and refunded my payment because of this issue.

If anyone has experience with these machines and perhaps knows what is causing this please share. Thanks!

[james_s]

That's quite an impressive result for such a low cost machine. Can you see what it's doing while it's running? You should be able to monitor easily when the laser is on, I would not want to look directly at the machine though, assuming it's using a violet laser there's a LOT more optical power there than it looks like.

[slow_rider]

@james_s - I have a piece of semi-transparent poly-carbonate that is supposed to make looking at this thing while operating safe. The machine does a raster routine, scanning line by line and turning on the laser when required ( = dark pixel). The shorter the exposure time, the faster the movement would be.

One of the problems is that when the time is set to anything but the minimum, I get burning smell from the plastic which is really nasty. I assume that the problem could be purely on the software side or related to the time it takes to the laser to turn off - but this is pure speculation.

[james_s]

That's strange that it uses a raster scan, plotters are almost universally vector as it's a better way of drawing nice clean lines. It does sound like the software is the main limiting factor here, as is usually the case with random Chinese widgets.

[slow_rider]

It's a POS. Period. Its laser is also used for alignment, and due to the poor firmware, sometimes the laser alignment indicator will go full blast a few milliseconds once per a few seconds, causing burning on darker materials. This is a major safety issue.

Too bad the MCU is not something I'm familiar with... I guess installing an Arduino + some additional hardware could cause this thing to work however a more series model is just $200 so I don't know my time is worth it :/ Too bad it's a nice little device.