ARG
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I started this project around January and today it is finally complete. The original build thread is lengthy and all over the place so I figured it would be better to start a clean thread as the old one didn't really explain what was going on that well. Much of the original design ideas in the OP are incorrect.
To view the build thread click here.
Click the pictures for full resolution.
Specifications:
Dimensions---------------------------231mm x 42mm
Battery Type-------------------------Two 32600 3.7V 5AH Li-ions
Output-------------------------------4.4W Peak 4.3W sustained
Wavelength---------------------------445nm
Beam Diameter------------------------Same as single diode with G2 lens (I tried to measure but my ruler keeps catching on fire!)
Beam Divergence----------------------Same as single diode with G2 lens (I tried to measure but my ruler keeps catching on fire!)
Duty Cycle----------------------------120s on 100s off
Current draw--------------------------appx 3A
Battery life----------------------------appx 1.5 hours on a full charge
Diode---------------------------------Two 9mm diodes (Link)
Driver---------------------------------Two 2A Lazeerer X-Drive (Link)
Lens----------------------------------Two 405-G2 Lens' in 405-G1 Lens barrels (Link)
Host----------------------------------Custom Ehgemus Host (Link)
Host:
The entire host had to be custom made for obvious reasons. It required some milling as well as lathing to make the optics tray. I asked Ehgemus if he would be able to make the host for me and he said he would. I made some sketches of what I wanted the heatsink to look like with measurements to fit the optics and left the rest up to Ehgemus. The results were amazing.
The heatsink is held in the host with a small set screw on the side.
Diodes:
Originally I was going to use two binned M140's for this project, but then the 9mm were discovered by DTR and I decided to use those since they can produce so much more :eg: I used extended copper modules that are longer than normal to house these diodes, this worked out perfectly because it allowed me to glue the lens barrel in place with ease and it provides more area for heat transfer.
PRE OPTICS:
Diode #1:
2070mW at 1.6A
2440mW at 2A
Diode #2:
2155mW at 1.6A
2590mW at 2A
POST OPTICS:
Diode #1:
2016mW at 2A
Diode #2:
2398mW at 2A
Batteries:
To power this I needed something that could handle the current draw. I decided to use two Li-ions so I could use a buck driver that puts out very little heat. I wanted to use Panasonic 18650's initially but I don't like the look of a laser with a head bigger than the battery tube, so I used 32600's so the body would stay the same size for the whole laser. The batteries I bought are rated for 5AH, but I think the real capacity is more around 4AH.
I wrapped some electrical tape around them to give them a better fit in the battery tube.
They have flat tops, so I used some magnets on the contacts to make them connect better.
Drivers:
For a two Li-ion configuration I used two buck drivers. I bought a couple of Lazeerer X-Drives to power this since they are small and easy to mount. I decided on 2A for the current, I could have ran the diodes harder, but then they would degrade really fast and replacing the diodes in this would mean re-alignment :yabbmad:
I cut some small aluminium bits to lie flat in the driver pocket so I could easily mount the drivers. They are held in with thermal epoxy.
I then wired up the drivers and tested them with a test load before mounting them.
Then I mounted them with more thermal epoxy to the stands. This provided enough room to slide the modules in after.
Optics:
To combine the beams I used a polarizing beam splitter. This takes two beams that are oppositely polarized, and knits them together. One beam passes straight through the cube, and the other beam gets reflected 90° so that they come out the same direction.
The disadvtange of this method with the multimode diodes is that the beams have to be positioned such that the wings are perpendicular to each other which leaves you with an awful + beam which has a lower power density. To change this I used a 1/2 wave plate, this changes the polarization of the beam but not the orientation of the beam so that I could put the beams through the cube so the wings overlap each other. This way the beam size is no different from a single diode laser with a G lens.
For steering the beam I used a regular FS mirror from Edmund Optics.
Putting the lens in was just like any other laser, I put the optics into the lens barrel then wrapped the threads in a bit of teflon tape. I had to use two G1 lens barrels because the G2 barrels couldn't get close enough to the diode to focus. I screwed them in until they were perfectly focused and I used some epoxy to glue them in place so they wont fall out of focus.
I designed the heatsink to utilize two modules rather than be direct press so I could rotate the modules and get the beams to the same position.
Alignment of the optics was the hardest part. I worked on it for hours and hours. I thought it would be hard, but I had underestimated how much work it is to align optics in such a small space. Every 0.03mm made a huge difference in alignment.
I first put down a piece of acrylic to prevent the optics from moving when the metal expands in the heat. (Thanks to JLSE for the tip!)
The wave plate was the easiest to mount, I just rotated it until the beam came out the cube straight, and not to the right then I marked the bottom with a marker and used epoxy to mount it on in front of the module hole.
The hardest part was the mirror and the cube. I mounted the mirror on a piece of aluminium with epoxy to make it easier to mount. I put the cube on the optics tray and placed the mirror down. I ran 250mA through the diodes to get them lasing. I pointed the entire assembly across the house to a wall 12m away so I could align the beams perfectly. I took note of the position of the beam, and filed the mirror mount down to get it closer to the other beam. This took forever to do, every 0.03mm of aluminium made a huge difference in beam alignment. Then once it was perfect I put some epoxy on the bottom and glued it to the optics tray. I then glued on the cube and rotated it slightly so the beams were overlapping perfectly. In the end the beam was coming out of the laser at an 85° angle. I didn't notice this when testing it at 250mA since the beam was not very visible. If I had noticed this when I was aligning I would have corrected it. It's not very noticeable unless someone points it out to you, so I wont undo all my work aligning the optics to change it.
Multimedia:
Assembly and insides of the laser
I built this laser for the bright beam and just for something to do; not really for burning, but I know I will get a lot of requests for it so here it is.
Derpy Burning Video
The laser was pointed at these objects from 4 feet away. It was not focused to a burning point, it was focused to infinity. The video was also taken on a sunny day.
The beam is visible somewhat visible outside in the sunlight, but I was unable to get a picture of it
Always use goggles when dealing with high powered lasers!
I am very sorry for the lack of good beamshots, I have only ever used one camera that took good photo's of the beam and that was my friends Nikon D5000.
I also had a problem taking these photo's. I didn't want to point it at the fence because it was wood and I didn't want to do it in the sky because of planes. So I pointed it at a spot in the grass 15 meters away, but after about 20 seconds I noticed a funny smell, and I turn around and there's a small candle sized flame. The grass caught fire :wtf: I'll get some better photo's once I can borrow my friends camera.
Until then enjoy these photo's. The camera did a shit job of picking up the beam, it looks incredibly bright in real life.
:thanks: for reading! If I forgot to add anything please tell me and I will do my best to add it to the OP. I would love to see more dual diode lasers built by others and I want this thread to be a good resource for others!
To view the build thread click here.
Click the pictures for full resolution.
Specifications:
Dimensions---------------------------231mm x 42mm
Battery Type-------------------------Two 32600 3.7V 5AH Li-ions
Output-------------------------------4.4W Peak 4.3W sustained
Wavelength---------------------------445nm
Beam Diameter------------------------Same as single diode with G2 lens (I tried to measure but my ruler keeps catching on fire!)
Beam Divergence----------------------Same as single diode with G2 lens (I tried to measure but my ruler keeps catching on fire!)
Duty Cycle----------------------------120s on 100s off
Current draw--------------------------appx 3A
Battery life----------------------------appx 1.5 hours on a full charge
Diode---------------------------------Two 9mm diodes (Link)
Driver---------------------------------Two 2A Lazeerer X-Drive (Link)
Lens----------------------------------Two 405-G2 Lens' in 405-G1 Lens barrels (Link)
Host----------------------------------Custom Ehgemus Host (Link)
Host:
The entire host had to be custom made for obvious reasons. It required some milling as well as lathing to make the optics tray. I asked Ehgemus if he would be able to make the host for me and he said he would. I made some sketches of what I wanted the heatsink to look like with measurements to fit the optics and left the rest up to Ehgemus. The results were amazing.
The heatsink is held in the host with a small set screw on the side.
Diodes:
Originally I was going to use two binned M140's for this project, but then the 9mm were discovered by DTR and I decided to use those since they can produce so much more :eg: I used extended copper modules that are longer than normal to house these diodes, this worked out perfectly because it allowed me to glue the lens barrel in place with ease and it provides more area for heat transfer.
PRE OPTICS:
Diode #1:
2070mW at 1.6A
2440mW at 2A
Diode #2:
2155mW at 1.6A
2590mW at 2A
POST OPTICS:
Diode #1:
2016mW at 2A
Diode #2:
2398mW at 2A
Batteries:
To power this I needed something that could handle the current draw. I decided to use two Li-ions so I could use a buck driver that puts out very little heat. I wanted to use Panasonic 18650's initially but I don't like the look of a laser with a head bigger than the battery tube, so I used 32600's so the body would stay the same size for the whole laser. The batteries I bought are rated for 5AH, but I think the real capacity is more around 4AH.
I wrapped some electrical tape around them to give them a better fit in the battery tube.
They have flat tops, so I used some magnets on the contacts to make them connect better.
Drivers:
For a two Li-ion configuration I used two buck drivers. I bought a couple of Lazeerer X-Drives to power this since they are small and easy to mount. I decided on 2A for the current, I could have ran the diodes harder, but then they would degrade really fast and replacing the diodes in this would mean re-alignment :yabbmad:
I cut some small aluminium bits to lie flat in the driver pocket so I could easily mount the drivers. They are held in with thermal epoxy.
I then wired up the drivers and tested them with a test load before mounting them.
Then I mounted them with more thermal epoxy to the stands. This provided enough room to slide the modules in after.
Optics:
To combine the beams I used a polarizing beam splitter. This takes two beams that are oppositely polarized, and knits them together. One beam passes straight through the cube, and the other beam gets reflected 90° so that they come out the same direction.
The disadvtange of this method with the multimode diodes is that the beams have to be positioned such that the wings are perpendicular to each other which leaves you with an awful + beam which has a lower power density. To change this I used a 1/2 wave plate, this changes the polarization of the beam but not the orientation of the beam so that I could put the beams through the cube so the wings overlap each other. This way the beam size is no different from a single diode laser with a G lens.
For steering the beam I used a regular FS mirror from Edmund Optics.
Putting the lens in was just like any other laser, I put the optics into the lens barrel then wrapped the threads in a bit of teflon tape. I had to use two G1 lens barrels because the G2 barrels couldn't get close enough to the diode to focus. I screwed them in until they were perfectly focused and I used some epoxy to glue them in place so they wont fall out of focus.
I designed the heatsink to utilize two modules rather than be direct press so I could rotate the modules and get the beams to the same position.
Alignment of the optics was the hardest part. I worked on it for hours and hours. I thought it would be hard, but I had underestimated how much work it is to align optics in such a small space. Every 0.03mm made a huge difference in alignment.
I first put down a piece of acrylic to prevent the optics from moving when the metal expands in the heat. (Thanks to JLSE for the tip!)
The wave plate was the easiest to mount, I just rotated it until the beam came out the cube straight, and not to the right then I marked the bottom with a marker and used epoxy to mount it on in front of the module hole.
The hardest part was the mirror and the cube. I mounted the mirror on a piece of aluminium with epoxy to make it easier to mount. I put the cube on the optics tray and placed the mirror down. I ran 250mA through the diodes to get them lasing. I pointed the entire assembly across the house to a wall 12m away so I could align the beams perfectly. I took note of the position of the beam, and filed the mirror mount down to get it closer to the other beam. This took forever to do, every 0.03mm of aluminium made a huge difference in beam alignment. Then once it was perfect I put some epoxy on the bottom and glued it to the optics tray. I then glued on the cube and rotated it slightly so the beams were overlapping perfectly. In the end the beam was coming out of the laser at an 85° angle. I didn't notice this when testing it at 250mA since the beam was not very visible. If I had noticed this when I was aligning I would have corrected it. It's not very noticeable unless someone points it out to you, so I wont undo all my work aligning the optics to change it.
Multimedia:
Assembly and insides of the laser
I built this laser for the bright beam and just for something to do; not really for burning, but I know I will get a lot of requests for it so here it is.
Derpy Burning Video
The beam is visible somewhat visible outside in the sunlight, but I was unable to get a picture of it
Always use goggles when dealing with high powered lasers!
I am very sorry for the lack of good beamshots, I have only ever used one camera that took good photo's of the beam and that was my friends Nikon D5000.
I also had a problem taking these photo's. I didn't want to point it at the fence because it was wood and I didn't want to do it in the sky because of planes. So I pointed it at a spot in the grass 15 meters away, but after about 20 seconds I noticed a funny smell, and I turn around and there's a small candle sized flame. The grass caught fire :wtf: I'll get some better photo's once I can borrow my friends camera.
Until then enjoy these photo's. The camera did a shit job of picking up the beam, it looks incredibly bright in real life.
:thanks: for reading! If I forgot to add anything please tell me and I will do my best to add it to the OP. I would love to see more dual diode lasers built by others and I want this thread to be a good resource for others!
Last edited:
