Laser

Hi all,

As I said, I've tested my machine after following the J Tech instructions.
As for the ON OFF it works without any issues.
Today I will try to test the PWM, but only with a multimeter it's tricky, the ideal tool would be a oscilloscope.

My laser will arrive next wednesday or thursday, so once I have all setup, I will update this thread.

Regards,
Rodrigo

hi,

use leds (if needed in a row). leds are dimmable via pwm !

Hi drilldevil,

Do you know what voltage is the PWM output on the machine? 0-5v?
I will do some tests and report back...

Regards,
Rodrigo

hi,

use leds (if needed in a row). leds are dimmable via pwm !

Here's a good (safe) way to measure PWM:

http://en-us.fluke.com/training/training-library/test-tools/digital-multimeters/how-to-measure-duty-cycle-with-a-digital-multimeter.html

Regards,
Rodrigo

Here's a good (safe) way to measure PWM:

http://en-us.fluke.com/training/training-library/test-tools/digital-multimeters/how-to-measure-duty-cycle-with-a-digital-multimeter.html

Regards,
Rodrigo

Hi Rodrigo,
any news on your PWM tests? I'm really keen to see the results. As far as I know the PWM output of the machine is 0...5V.

Thanks and best regards,
Sol

Hi,

I got the laser working as expected.
I've followed the Jtech manual on the connections and got it working.
You can check it here: https://jtechphotonics.com/?page_id=3905

Here's the connection to the controller:

The power source i've used:

You will have to connect the + and the - to the laser and the + and the - of the PWM also to the laser, you cannot use the negative power source and connect to the negative of the PWM output.

I will try to explain:

Laser Power + to Power Source +
Laser Power - to Power source -
Laser PWM + to PWM + of the machine controller
Laser PWM - to PWM - of the machine controller

The view from the front of the laser:

From the top:

I've also used a MPX connector so that if needed i can connect and disconnect the laser at any time:

Here's the connector type:

This kind of connector is rated for 35A so it's more than enough for my laser. It draws 3A and the PWM current is very low, so no issues here.

One of the first tests i've made:

And now some short video also from a test:
https://dl.dropboxusercontent.com/u/18756250/20161215_224017.mp4

With the PWM output you are able to control the laser output power.
I dont know what software you are using to generate the code but you just need to change the "spindle speed" and that will be propagated to the PWM proportionally.

I managed to do some engraving generating the gcode with vectric. I've also used the "mach3 laser" post processor that Jtech have on their site. https://jtechphotonics.com/?p=3851 In my opinion it needs some improvement. When machine moves to the place where it will start to cut, it activates the laser but stays on that place a few moments, for instance if I want to cut some balsa wood it will burn the wood too much while in that position.

Maybe someone can help improoving this post processor it would be great! Jtech have just released the post processor for UCCNC, I will give it a try as well.
As for picture engraving with laser, i've tested the PicLaser software but i was unable to set it to my machine, by the way its an 840...
Again if someone could help on their experiences with picture engraving it would be great!

Well for now this is my 50 cent on this matter. Please feel free to comment and ask questions if needed.

Regards,
Rodrigo

Hi Rodrigo,
great! Many thanks for sharing your experience! This really looks succesful!

Unfortunately my configuration is different: WinPC-NC USB (different control board) plus EstlCAM. I was not able to transfer the instructions for Mach3 to WinPC-NC yet.
One possibility to adjust the GCODE appropriately is using LaserCAM (see thread https://www.stepcraft-systems.com/forum/software/3687-lasercam, unfortunately in German).

As soon as I got my Laser head (I'm in favour of the 6W Laser from Opt Lasers) I will try LaserCAM and report.

Last question: do you use a laser tight housing? And if so could you share some information about it?

Many thanks again,
Sol

Hi Rodrigo,

one possible hint for the problem with the waiting when the laser starts:
Typically in the Software there is a delay entered for the software to wait after the spindle to start.
The purpose of this is to ensure, that the spindle reached the correct rpm. I guess for the laser this is not really needed. Maybe you can try to switch this off.

BR
Roy

Hi Solarier,

I will have a look on the thread you say... 🙂
Regarding the laser housing, I am not using one, when operating the laser and the machine I user laser protection goggles.

@Roy,

Do you know what parameter needs to be changed in order to remove the delay?

Thanks for your comments.
Regards,
Rodrigo