Does any one knows why LW4 stop working in the middle of the job

Hi everyone

I hope you are well and safe

Well, i have a VG-L7 20w since January, its a pretry cool machine for engraving fun or to do a small business. Normally the software came with those laser machines are a little bit limited as for exemple if you want add a grayscale photo to the galery is quite difficult.

You can work with others free Softwares as LW4, GBLR, or, pay a anual fee to use LightBurn (its a good program too).

I recomend you to use GIMP and Inkscape, if you want work, change, resize, etc images for free.

After all this months, i came across with a LW4 problem when i lasering a image. Some how, my laser stops working in the middle of the job and LW4 crashes. Its something didnt happen before, is anyone have a idea that could provoque this?

Thank you in Advance

What exactly do you mean by “LW4 crashes”? Do you get a bluescreen, or is LW unresponsive? Does it always happen or just with that one file? How big is the image you try to engrave?

Hi @cprezzi

Has been happening with a lot of files, yesterday i was trying do 4 PNG files and all fail. When i look to the g code window in LW4, show up a weird characters

. The machine just stop working, and i need to reboot the machine and LW, because LW4 takes to long to become responsive again. I already uninstall everthing incluiding drivers and install again and i keep with the same problem. Do think could be from the laser machine? Not from LW4?

Thank you

That looks like an unstable USB connection or bad machine controller.

  • Do you use a cheap (or long) USB cable?
  • Are there sources for disorders nearby (like aircondition, washing maschine, morots)?
  • What controller and firmware do you have?
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@cprezzi :dart:

More thoughts along the same lines: An intermittent bad connection on the device could cause this too; it doesn’t have to be directly part of the USB connection. Could be a bad ground connection. Or an intermittently-failing power supply. Noise that starts showing up without any software changes can easily be from a physical source. These diode lasers have wires that have to move to get to the laser head. This can end up with broken wires inside a cable that almost always connect except when the flex a certain way, or (more likely) an imperfect electrical connection; lots of ways things can go wrong. In any case, I agree that this looks like electrical noise of some sort.

@cprezzi anwser your questions:

  • Do you use a cheap (or long) USB cable?
    -I use all time the same, its what come with the machine, i even, swap the cables, the lasers, connect the usb cable to another usb port after sugestion and i still with the same problem.
  • Are there sources for disorders nearby (like aircondition, washing maschine, morots)?
  • What controller and firmware do you have?
    • Its a generic Laser machine, VG-L7, GBRL Firmware and I use LW4 to Controll the laser.

I got last month a CNC router Machine, that i couldnt out working yet, but the CNC machine use the same door as the laser machine, better the driver is the same. Could i have some conflit between machines?

And in meantime, @cprezzi and @mcdanlj, for the first time, i down the S: Value (i dont have a sure what S: value mean, but seems be the PWM max S value??? I dont get), from 100% to 80%, and so far that weird letters in GCode Window i said before, doesnt show anymore and looks the laser machine its working without any problem…

Could you explain whats going on?? Is it the laser controller starting be burn, a software conflit between to machines?

I starting feel that i need to format my pc

Thank you for your help

Yes, the S value is relatet to the laser power. In GRBL you set the maximum PWM value by $30=1000 (default is 1000), which represents 100% power. The set maximum also needs to be configured in LW.

Now when you reduce the S value from 100% to 80% your laser draws less power from the power supply. This could mean that @mcdanlj was right and your power supply might be unstable at maximum power.

Thank you @mcdanlj and @cprezzi, you were right is the power supply is not working very well, i need to order a new one.

Thank you again guys!

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Just a quick question before i buy another power supply, because you said that my power supply is unstable, is the power supply 12V 5A good for a generic Laser 20w or should i get higher supply?

Good question. I guess the 20W are peak power consumption, so 20W / 12V = 1.7A. Add the peak current of each stepper motor, fan, light and what ever you will connect to that power supply and you get your maximum consumption. Guessing the stepper drivers can deliver max. 2A would mean you need at least 1.7A + 2A + 2A = 5.7A (+ some margin for electronics).

You might get away with a 5A supply if your stepper drivers are set to max. 1.5A.

Just a comment on calculating the necessary power output of the PSU: If the “20 W” refer to the output power of the laser, then the power consumed by the laser will be higher. CO2 lasers (which are efficient as lasers go) have an efficiency of around 20 %. I.e. a CO2 laser with 20 W output power will consume around 100 W of input power.

Ah well, I just googled that machine, and they specify the laser power as 2.5 W. So the “20 W” is probably the input power to the laser.

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Thank you very much fellas!

I just bought a new machine because i tried different power suppliers and i getting the same problem every time. seems the board can handle more energy even when im using in low power…

thank you again