Computer power supply & FlexDrive V5

I'm new go easy!!

Two questions:

I just ordered my first ~1W 445nm LD. I'll be using it with a FlexDrive V5. I'm not planning on building it into a host so portability doesn't matter. Rather than dealing with batteries etc, any reason why I can't use the 3.3v or 5v on a computer power supply output and then use the V5 to trim the current?

Also, with the Aixiz Ar coated lens, what is the tightest focus possible at a few inches? I've watched lots of vids on burning etc but I haven't seen any close ups on what they burned/etched etc..

Thanks guys!!

AND YES I GOT GOOD 445nm Goggles!! lol.

You cant use the 3.3V supply because the voltage is too low for the driver. I think that it will work with the 5V. Now about the focusing part, wear your glasses and try to make the dot as small as possible ! There isnt any other way !

Jim

^The datasheet says 2.0V-5.5V. It will run more efficiently at 5V though.

Yeah, I don't see any reason why it wouldn't be a great power source. Plenty of nice stable current, not to mention it has 12v also to drive my cooling fans and stepper drivers

I really just wanted to reinforce what I already thought! I want to make sure I don't botch my first 445 build as I don't have any experience with the v5 etc.

I'll be fixing this guy to a small X/Y CNC machine I've been building to do some wood/paper burning. Looking forward to getting the tightest beam I can at a few inches or so..

The PSU will be fine.

You're not going to get a good beam out of a 445nm laser. They have terrible beam specs (rectangular). You might do better with a 405nm laser, as they have a single mode profile (round).

Better yet, a CO2 laser is your best bet as it puts out long-wave IR (heat) instead of the visible spectrum light of laser diodes.

Thanks for the input so far -

Bionic-Badger said:

You're not going to get a good beam out of a 445nm laser. They have terrible beam specs (rectangular). You might do better with a 405nm laser, as they have a single mode profile (round).

Better yet, a CO2 laser is your best bet as it puts out long-wave IR (heat) instead of the visible spectrum light of laser diodes.

Click to expand...

As long as it is a small rectangle i.e. 1/2mm-1mm max or so it will be fine..

I love the CO2 lasers no doubt but they just seem overkill for what I want to do and a little on the $$$ side to start hobby paper/wood burning. No need to cut anything yet, not until I'm more familiar etc. I like the small footprint of the diode and no need for extraneous optics etc..

So would it be in my better interest to be looking to the IR diodes then? From what it sounds like, I could get the same amount of burning power out of a lesser powered diode, say 500mw 808nm etc???

PLEASE put your location in yr profile, there may be a member close to you for hands-on help.

Lase safely- use your glasses always.

An 8X or 12X 405nm may be your best choice with AixiZ glass lens for blue.
Very quick burner with small beam at low cost to make. A new thread just went up on the 8X.

hope I have helped. if so please donate to the forum.

len

ps
take some pics as you build this and post them..... we love lots of (resized to med) pics.

Thanks Len, I updated my profile a bit

So you think the 445nm will be to big a beam for what I'd like to do then? I suppose I'll just have to machine a nice host for it after all jk

Do you guys have any specs on the beam size of the 445nm w/ Aixiz lens? I did find a post about the shape of it, it showed the beam at a distance of about 40ft and it was an inch long or so...How about close up? a few inches a way?

I'll look into the 8x & 12x 405's, low cost - can't go wrong. I really want to build a small array of them equal distance apart on my cnc so I can burn multiple identical pieces simultaneously - Speed it up a bit and reduce duty length/cycles.

Once the parts start coming in/together i'll post my build. Thanks for the help guys!!

I'll see if I can add that donation to my BOM (sneak it by the Ol' lady)

One of our mods and resident expert on CNC is 'Things' see his posts and those of others on this topic(use search)

I dont know much on this but-- it is easier IMO to get a bigger spot when wanted by adjusting the focus- however the 445 will not allow as small as you may want w/o a lot of additional optics- just my 2 cents. Both burn at about the same rate and sometimes the 405 is even quicker.

and do be careful to not overheat!!!

About the donation ,,,just a few dollars helps a lot.

Thanks for the pointers - I'll be sure to have some more questions along the way. I'm going to experiment with the 445 for now as it's bought and paid for. We'll see if it will suffice for now. I've got access to a graveyard of old computer towers full of heatsinks and fun stuff. I'm already brainstorming creative cooling methods and I don't even have my 445 or driver yet. Size isn't really a problem so I should be able to give it adequate sinking. I'll try to adjust the current to no more than I need as well - I'd like it to last!

One more question about the computer PSU. I plan on powering the V5 with the 5v source as it sounds like its closest to the ideal input voltage. 12v would work as well but would just result in extra heat it sounds like?

The real question,
Do I need to limit the current before the V5 as well in this case? The 5v out on my PSU is capable of 30A for example. Or will the driver only demand what the output is set to?

I found similar threads but slightly different situations. Thanks guys!!

The Flexdrive only has a max input voltage of 5.5v so you would not want to use the 12v rail of the computer psu unless you enjoy breathing magic smoke from a $30 diode driver

The Flexdrive itself is a current regulator, it will only consume as much power as it needs to drive the laser diode at the current you set using the jumpers and potentiometer on the driver's PCB.

The PSU is rated for 30A on the 5V rail, that is a maximum rating. The PSU provides a constant voltage, the Flexdrive provides a constant current (by adjusting the voltage until it reaches the correct current) - This is important for laser diodes because they consume almost no current until you reach their threshold voltage where suddenly current goes through the roof.

That should help explain the function of laser diode drivers and why they are favorable over simple resistor or a constant voltage source. Changes in battery voltages or diode characteristics like temperature can have large affects on how much current flows if you are not using a current regulated driver.

Perfectly explained - Thanks Mario!