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My first build - 2W M140 diode laser

nzoomed

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Thanks lifetime17 for the host!
This is my first laser build ever.
I grabbed an astral drive V off ebay and an M140 diode.
Its using a g8 lens, and as others have said, you don't get an overly tight beam and its slightly parabolic in shape I'm pretty sure.
The beam is bright as hell and leaves a trail just like how you would write your name with a sparkler as a child.
I had to turn the lens round backwards to be able to screw in to get the right focus as the diode housing did not have enough thread to focus.
 

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GSS

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:)Nice and well done!
Is that a Dtr 12mm copper module?
I have been skimming posts on the G8 lens and haven't seen a issue with limited threading on a module, only the G7.:unsure:
Maby RedC will chime in.
Enjoy, be safe and glad it brought back childhood memory's!
 

trephanation

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Very nice. I've also got a Lifetime17 host on the way and I'm going to put an Osram PLTB450B diode in it as my second ever build.
 

paul1598419

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I would get my hands on a G2 lens. The M140s have pretty good beam divergence specs that don't necessitate the use of the longer focal length lens. You should do fine even with the short focal length lenses offered on eBay for under $8.00 each. Unless you are trying to see the beam profile at great distances you don't need a G8 or G7 lens.
 

nzoomed

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:)Nice and well done!
Is that a Dtr 12mm copper module?
I have been skimming posts on the G8 lens and haven't seen a issue with limited threading on a module, only the G7.:unsure:
Maby RedC will chime in.
Enjoy, be safe and glad it brought back childhood memory's!
Yeah I didnt think much about doing that, but remember i just bought a lathe, so I could try cutting it down a MM or two I guess?
No, its not a DTR module, its just a cheap one I bought off ebay that came with a lens but swapped out with a better G8 lens.
The part that the diode is pressed into definitely looks like copper, but not sure about the chrome part as I never filed it off to see what it looked like.
I might grab a DTR one later, as it didnt feel very tight in the host and slipped in rather easily, im not sure if the DTR ones are a different diameter or not? My main concern was thermal heat transfer, I put arctic silver grease all around it, so hopefully that helps.


I would get my hands on a G2 lens. The M140s have pretty good beam divergence specs that don't necessitate the use of the longer focal length lens. You should do fine even with the short focal length lenses offered on eBay for under $8.00 each. Unless you are trying to see the beam profile at great distances you don't need a G8 or G7 lens.
OK interesting to know, I had been advised that a G8 lens would give the best efficiency, but at the expense of not a nice tight beam.
This thing burnt my carpet about 2 metres away, so it certainly appears to be giving its full power.
If i go with a lower efficiency lens, will the beam still look as bright in the sky?
I dont care too much about seeing the bean profile at long distances, if anything, I would be happier with a more tight, round dot at a longer distance, my main concern is not loosing too much power.
It almost looks kind of like it does produce a tight beam, but has a fatter secondary beam that slightly surrounds it like a very narrow spotlight.
Im assuming this is due to the optics?
I should grab a G2 lens and see how I like it I guess. The module I bought on ebay does come with a glass lens, so I guess I should try it too.
 

paul1598419

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The efficiency of the Chinese G2s are better than the G8. You won't lose more than 5% and likely less than that. I have purchased several over the years and they aren't that bad. Not as good as DTR's G2s, but a lot cheaper.
 

Lifetime17

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Hi,
Glad to see you accomplished building your first, and really no problems . As stated the G2 will give you max power out of the diode and the divergence of the M140 is great for starters . when you pic up a G2 you will see the difference .
Rich:)
 

GSS

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nzoomed, are you sure the module came with a glass lens? If it's plastic it may melt and cause issues..
 

nzoomed

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The efficiency of the Chinese G2s are better than the G8. You won't lose more than 5% and likely less than that. I have purchased several over the years and they aren't that bad. Not as good as DTR's G2s, but a lot cheaper.
I tried my cheap glass lens that i got from china and i think it does have a tighter beam, but still did not feel like it could quite focus as good as it should.
I will definitely try a g2 lens and see how that goes, I have absolutley no idea what kind of lens it is.
Hi,
Glad to see you accomplished building your first, and really no problems . As stated the G2 will give you max power out of the diode and the divergence of the M140 is great for starters . when you pic up a G2 you will see the difference .
Rich:)
Thats great to know, will post an update once I get the lens. I have no idea if the cheap lens I have is G2 or not, but looks like its got moe than a single element.

nzoomed, are you sure the module came with a glass lens? If it's plastic it may melt and cause issues..
Its definitely not plastic, ive tested it and not melted so far, also looks like it has a coating on it much like camera lenses have.
This was what I bought:
 

paul1598419

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The Chinese G2s are single element short focal length aspheric lenses. The FL is ~2.39 mm. I have not seen any that didn't come in a brass lens holder so if the lens holder is black it likely isn't what you're looking for.
 

nzoomed

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The Chinese G2s are single element short focal length aspheric lenses. The FL is ~2.39 mm. I have not seen any that didn't come in a brass lens holder so if the lens holder is black it likely isn't what you're looking for.
OK, good to know, Ill grab a G2 off ebay and see how I find it.
 

nzoomed

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This is the only G2 lens I can see on ebay and it says its for laser engraving, so im assume it would have a very fine focus to a point and give a very narrow beam? Im not sure if its a G2 going by this or not.
Doesnt come in a brass lens holder by the looks either.
 

Lifetime17

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Hi,
I clicked on the listing you provided , but if you scroll down theres a G2 in a brass barrel for 12.00 that will work fine
Rich:)
 

nzoomed

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Thanks for that, Ill grab one.

Whats the story with star caps?
Is it possible to get one that will fit this?
 




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