Getting a coherant 40w 808nm

Ok, the unit I bought has a TEC cooling built in, but it's going to need to be mounted to a very large heatsinc W/ a fan.
as soon as it gets here, I'll take some pictures if anyone is interested.
I'm assuming since the TEC is built in, it's already enough to do the job of keeping it frosty.

Yes, the built in TECs will do fine to keep it cool. The problem is when you take into account you now will need another high current power supply for them...

lv128 said:

Ok, the unit I bought has a TEC cooling built in, but it's going to need to be mounted to a very large heatsinc W/ a fan.
as soon as it gets here, I'll take some pictures if anyone is interested.
I'm assuming since the TEC is built in, it's already enough to do the job of keeping it frosty.

Click to expand...

Glad it's got a TEC! Saves you a little extra there - IIRC some version don't have a TEC and some do, you will need a good few amps for that too @ 12-15V. Just don't let it get TOO cool

For powering the diode I have a "schematic" for a variable voltage high current source capable of up to 100s of amps. Though I don't know how well it works.

How much did that LD cost you anyway, if you don't mind my asking ? If you don't want to post it can you pelase PM me ?

diachi said:

Glad it's got a TEC! Saves you a little extra there - IIRC some version don't have a TEC and some do, you will need a good few amps for that too @ 12-15V. Just don't let it get TOO cool

For powering the diode I have a "schematic" for a variable voltage high current source capable of up to 100s of amps. Though I don't know how well it works.

How much did that LD cost you anyway, if you don't mind my asking ? If you don't want to post it can you pelase PM me ?

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I don't mind telling I only paid $100 for it pre-mounted in the TEC/enclosure, it's got screwholes around the outside edges to be mounted to a HS.

There is a chance it may not be functional since they're "new old stock", and untested however I have a guarantee from the company that they will replace it if it is not since they have "bunches" according to the guy's e-mail.

My concern now is finding an SMA cable for it and a collimating lens and I think I'm in over my head on that part since I'm not really sure where to start looking.

I think I might have found a few SMA fibers but the other end is bare fiber and I don't have any fiber tools for connecting/polishing anything to it.

Is the seller from Nor-Cal? If not, those are old units replaced, it's probably from an Avia 355-X or a Verdi.

I'm assuming that's northern california, and yes, it appears they are.
Is this a bad choice then? What kind of usage do you think they've had or have left in them in this case?

Coherent does not throw them away unless there is a problem. This can be some very minor damage, or it could be serious damage such as total failure, poor spectrum, or bad efficiency. I can be 99% sure if this came from Coherent or a Coherent disposal company that this was a replaced diode from a Verdi, Avia, or other system. It has some problem, the severity of any damage is up in the air. Some have been shown to be working perfectly, with no noticeable damage.

Well, Hopefully when I get it, it's not in terrible condition, I'm not sure if spectrum is a concern. Effeciency and failure doesn't sound good though.
Wonder what a 40W coherent goes for in new condition....

lv128 said:

Well, Hopefully when I get it, it's not in terrible condition, I'm not sure if spectrum is a concern. Effeciency and failure doesn't sound good though.
Wonder what a 40W coherent goes for in new condition....

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Wonder what a 40W coherent goes for in new condition... You really don't want to know...

FWIW I have bought 3 of these coherent 40W units and he is right all had some problems.

On one a few of the emitters in the bar were dead, In another the TEC was bad, and in the third unit the sensor that detects power had a cold solder joint that went bad giving a false low power reading.

The good news is that all the lasers are usable for a hobbiest application.

The units that were bare without the cooler assy are a crapshoot, I'v bought ones everything from fine with minor cosmetic damage to totally DOA to something in between
as the fiber bundle assembly was badly soldered and came lose, but the diode and it's FAC lens were savable.

It looks like I might have dodged a bullet then, I was just told that the one I was going to be sent was 'no longer available' aside from that, I figured I don't have the ability to get these suckers up to full power without doing some changes to my panelbox.
I think I'll reinvest my new spare funds into a 4W c mount diode instead. I should be able to make a real nice burner out of this. Any recommendations on a c-mount host/HS assembly?

I hate to be a spoilsport, but this is beyond you.

Dangerously so, as evidenced by even needing to ask about eye protection.

When making a laser soldering pen, the ideal output range is about 7W or so, and using eye protection is mandatory for everyone in the room. The room should be locked, with a clearly visible warning sign, and should have no windows. The glasses worn should cover the sides of the eyes, and be an approved type (available for ~$150 from the company Chimp works for). You should have interlocking, a warning light, delayed startup and so forth. It would be a major plus if there were a dead man's handle on the pen.

You do not need to focus the light, only collimate it. You are not trying to melt a small point on the surface, but rather evenly heat all the solder and the surfaces it should be soldering. The reflectivity of solder and copper are high in this wavelength range, and a significant fraction will bounce randomly around the room.

Are you using flux free solder?

As for introducing a guide beam, there are modules available that have red guide lasers installed inside the module. Go ask Z-Optics about their fiber coupled modules, which are available at a suitable power level with TEC and guide beam. Then get an experienced forum member to make the unit for you and teach you the safety precautions. Buy the goggles before thinking about buying the laser.

If adding a guide beam, a dichroic beam splitter is the simplest way, but you will have the problem that the guide beam needs to be aligned with the solder beam, which is a tricky task without good equipment or a lot of experience. As an alternative, you could collimate the fiber output, direct it into a dichroic beam splitter cube, add a collimated red or green guide beam, then refocus it into a new fiber and collimate the output of that instead, since the alignment will be a matter of efficiency instead in that case.

Still, I'll reiterate: it is dangerous to attempt this at your current level of experience.

Perhaps one of the people on the board would be willing to make a suitable unit for you?

suiraM said:

I hate to be a spoilsport, but this is beyond you.

Dangerously so, as evidenced by even needing to ask about eye protection.
....


Still, I'll reiterate: it is dangerous to attempt this at your current level of experience.

Perhaps one of the people on the board would be willing to make a suitable unit for you?

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I totally do not disagree with you which is why I abandoned my line of inquiry, got some high quality glasses and resumed my newbie experiments on small IR cans. I'm coming to grasps with how difficult invisible light is to work with and if I had ended up getting the coherant module I'd probably be blind by now.

So I am somewhat reckless, but not dangerously so

Knowing most of it will be reflected, are you sure 7W is enough?

7W is used in a commercial laser soldering gun a former colleague liked to show off. The wavelength was in roughly the same range. I have seen adverts for a 9W commercial system intended for CNC controlled assembly. However, I am not sure about whether the solder used was mixed with anything (e.g. pyrene is used in the UV), so it may be too low. Anecdotes posted by others here indicate it should be enough without additives, though, so I'm assuming the former colleague was stating the correct specs. Might not be good beyond SMD scale, tho', which is where laser makes sense, anyway.

If making a nitrogen CW laser is comparable to making a carbon dioxide CW laser, then I think that may be the ideal thing for soldering. Easy to make a shield for the UV, and a wavelength that is absorbed by just about anything. Copper absorbs 40% at 405nm, but more like 80%+ at 337nm. Guessing it'd be good for UV activated etching, too. Galvo and PCB, anyone?

So where is this driver schematic? I am considering getting one of these also, I want to put it into an enclosed old printer and use it for engraving and cutting thin material. Anyone with usable information please let me know.