dissapointed with my 1.5W 445 build's performance. (lots of pics!)

I just got in the parts for a 1.5 watt build consisting of a:

1W 445nm diode
brass module with a G-2 coated lens
1 microflexdrive.

I assembled them as shown for testing untill they are established in a host:

The module's heatsink is a bunch of copper washers silver soldered in a stack, then machined down to accept the module tightly, and with some arctic silver 7 compound and a setscrew. The flexdrive's 5-pin chip (and the back of the driver in general) was covered generously with the thermal compound, then pressed against a RAM heatsink I bought at microcenter.
The battery pack is meant for four AA batteries, but I am running three for 4.5 volts.

Here's how I soldered a jumper on the flexdrive to get my mA range set. *NOTE I do realize that I must also include in the circuit that "spot" seated in the corner of the "L" made by the jumper. I did this after I took this picture.


Unfortunately, in the process of adjusting the potentiometer for the highest output, the screwdriver head (which I also belive is the wiper for the pot) on the potentiometer broke off.

This is very disheartening, as the driver cost $30 (which I couldn't belive, for such a tiny, simple circuit.)

All I want out of the driver is all it can give me. Is there a chance that the circuit (without the pot wiper in place) is giving me full output?

Also, the beam divergence is terrible. Even focussed fully, The line on a wall 20 feet away is easily 2-1/2 cm wide, and subsequently it will only light matches less than 4 feet away. Heres a pic of the ebay module I bought:


Does anybody else have experience with this module? Should I use a different one for better divergence?

Thanks!

Feathers

beamshots! I almost forgot.

The top cover of the trimmer breaking off is not new to me I was harvesting tiny trimmers for my DIY drivers and that happened a lot.

Anyhow, about the focusing, divergence of 445nm lasers and beam profile in general is terrible, but it should look like a normal, non-diverging laser beam when you're looking down the beam. Like any other laser.

Basically, yeah at 6-7 meters, line being 2 cm wide is normal.

The divergence from this diode is normal.
You should have read more about how "wide" the "line" from this output was

Three AAA's won't give you the current needed to support that driver/diode setup

You broke your driver.
IIRC, the user sheet says specifically that an insulated screwdriver and a "light touch" is recommended

At least you've got blue light.
MANY people building their first laser break/blow them

Peace,
dave

highvoltagefeathers said:

Does anybody else have experience with this module? Should I use a different one for better divergence?

Thanks!

Feathers

Click to expand...

You can sacrifice some power and clean up the beam a bit by replacing the aspheric
with an inexpensive aixiz glass lens. The aspherics are nice for power and the
thin beam leading out of the aperture, but the divergence is much worse
than a standard 3 element.

Eudaimonium: I see. I'd read about that on the forum, just didn't quite know how bad

Dave: I am using 3 AA batteries, not AAA. I had read about the peculiar beam profile of these diodes, and how the output is a sharp line rather than an oval, but just wasn't expecting it to be that bad. Just wanted to make sure its not my module/lens setup.

And I read the manual, but again I underestimated how fragile the component was!

daguin said:

The divergence from this diode is normal.
You should have read more about how "wide" the "line" from this output was

Three AAA's won't give you the current needed to support that driver/diode setup

You broke your driver.
IIRC, the user sheet says specifically that an insulated screwdriver and a "light touch" is recommended

At least you've got blue light.
MANY people building their first laser break/blow them

Peace,
dave

Click to expand...

Dave, he says uses AA batteries, and if is a good alkaline batteries, can work, not is the best battery, but can operate.

Edit: highvoltagefeathers It was faster than me

You can remove the trimmer and hardwire the left side with the top-right. I think that way the driver is set at the max.
The heatsink around the module is a good idea but at 1.5A current it can't dissipate the heat fast enough. The diode will still overheat inside the sink. You need an active cooling and/or a bigger surface of the sink.

Blord said:

You can remove the trimmer and hardwire the left side with the top-right. I think that way the driver is set at the max.
The heatsink around the module is a good idea but at 1.5A current it can't dissipate the heat fast enough. The diode will still overheat inside the sink. You need an active cooling and/or a bigger surface of the sink.

Click to expand...

Blord: I literally JUST did that, like 30 seconds ago, and it looks like its back up to maximum. Good advice! Probably works better than the potentiometer set at maximum, as it bypasses that /tiny/ bit of resistive element left.

Thanks everyone! I'll upload pics of the finished project in host soon!

Hm, what worries me a bit is how the module is fitted into the copper heatsink.

There appears to be a 2mm thick layer of something between the heatsink and module itself. How did you fit it?

Eudaimonium:
The module fits the heatsink with almost zero clearance. The reason there is extra thermal compound around the back of the module is because I pushed the module in backwards, having spread the compound around the inside of the heatsink. It pushed the excess out the back, and I wiped it off, you're seeing whats left .

Good eye though...

Ahh cool. I was already starting to think you used like 2 mm thick thermal foam or something.

Cooling should be at level, I say you don't have to worry about overheating the diode anytime soon.

Yup! It doesn't heat up much. When I get my host, I'll go the extra mile and get some solid copper stock to make a heatsink out of for the driver and module.

Cool! Make sure to post some picz of that beauty!

Seems like its working pretty well, the divergence problem is normal for the 445 diodes and no fault of you or the components you ordered.

As for the potmeter: hardwiring to the max is one option, but you could use an external potmeter... or carefully snap away the leftover body of this one and solder an identical one on top.

Wow, that laser reminds me of the first laser I ever built. Granted your is much higher powered...

Mine didn't have any additional heatsinking like that because it was one of the first blu-ray diodes. Before the time of 445nm.