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Minimum power.

Posted: Sat Oct 03, 2020
by Kim Bahnsen
Newbee question...

Have a 80W laser, and installed a mA-meter in the machine.
Found out, that anything below 25% gives me an output of aprx. 6mA.
Can't get it any lower., even at 5% I get 6mA...
Is it the powersupply, or the tube that doesn't allow me to go lower than 25% ?

Regards, Kim

Re: Minimum power.

Posted: Sat Oct 03, 2020
by Pete Cyr
Welcome Kim.
So - it is not clear yet that you can not get to a lower power level.
It could be that you power meter is the issue - so a real world test is necessary to determine if you can or cant get to a lower power.
I have attached a link - download the file - unzip and burn. ( this is also a good bench mark to retain and evaluate performance over time)
You will be able to inspect the result and determine what you minimum power is from comparing the various burn depths.
It is not uncommon to be unable to get below aprox 10% - many glass tube laser just wont develop enough output to burn at the very lower powers.


viewtopic.php?f=104&t=3475&hilit=boss

Re: Minimum power.

Posted: Sun Oct 04, 2020
by Chris Medcalf
Take a look in the Vendor settings (read them from the machine before coming to any conclusions). If I remember rightly - and it's a long time since I experimented with it, just to see what happens - the minimum power in there is used if the power requested is non-zero, but less than that minimum.

Re: Minimum power.

Posted: Sun Oct 04, 2020
by Kim Bahnsen
Thanks, Chris, will have a look.
And Pete, looks that you were right. I can get an outpot down to 7%.
Below that I get nothing. Tried it on a birch plywood. See attached pic.
Didn't go above 45%, since it didn't get any darker, just deeper.

/Kim

Re: Minimum power.

Posted: Sun Oct 04, 2020
by Kim Bahnsen
Vendor settings, Chris

Re: Minimum power.

Posted: Sun Oct 04, 2020
by Pete Cyr
viewtopic.php?f=139&t=3479

I would recommend not operating your laser greater than 24 milliamperes (ma). Different manufacturers have slightly different max current ratings. With that in mind check to see what %power = 24ma. After you determine what %pwr = 24ma go back to vendor settings and set max power to the %pwr = 24ma. The link shows a couple of tables for glass tube laser operating specs.

As for your burn test not getting darker ...only deeper ...well that indicates you are achieving higher power...the deeper the burn the more energy is being used. At some point it will not darken only deepen. I recommend performing you test again or if you still have the one that was the full range of power use that as you base line for future reference.

Different woods will burn differently with regard to darkness, charming etc, based upon factors such as resins, glues in plywood, natural oils and tanins in wood, hardness and other properties of various woods.

Re: Minimum power.

Posted: Sun Oct 04, 2020
by Pete Cyr
Kim Bahnsen wrote: Sun Oct 04, 2020 Thanks, Chris, will have a look.
And Pete, looks that you were right. I can get an outpot down to 7%.
Below that I get nothing. Tried it on a birch plywood. See attached pic.
Didn't go above 45%, since it didn't get any darker, just deeper.

/Kim
see previous post

Re: Minimum power.

Posted: Mon Mar 15, 2021
by Joseph Leavell
Kim Bahnsen wrote: Sun Oct 04, 2020 Below that I get nothing. Tried it on a birch plywood. See attached pic.
/Kim
In the attached photo, would you be willing to share your cut parameters? This looks like a super neat way to run a test, and I couldn't come up with something like this. I was attempting to make a full circle from 0 to 255 darkness

Re: Minimum power.

Posted: Mon Mar 15, 2021
by Pete Cyr
Open the link In the second post in this thread....you can down load the file

Re: Minimum power.

Posted: Tue Mar 16, 2021
by Joseph Leavell
Oh, thanks! I didn't see that. Is there any reason people don't use something like this to get a full spectrum?
msedge_9VIbhg8UTb.png