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5.5w 450nm blue laser very week

khomouda

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Hi.
I bought theelow laser to use in a cnc for engraving. it is supposed to be 5500mw and have a driver that came with it.

https://www.aliexpress.com/item/550...-laser-module-450nm-12V-blue/32795864565.html

it worked initially in burning but at full power was burning slightly and I did not know how strong should it be, till once, I was measuring the height by a metal ruler and got spark, then it stopped burning, and was very week.
I examined the driver board under the microscope, which showed white traces around the opamp. anyway I bought another driver and got an opamp and installed it, and now both drivers are working similarly. it burns wood very faintly, so i measured the current at the driver output and it reads 0.6A at 5v in both drivers, is this enough or the boards are faulty or the diode is faulty or what...thanks a lot
 

Lifetime17

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Hi,
It would be nice to post in the welcome section first instead of coming in and asking for help. How about your global location and I little about your self. So others will be willing to help.

Rich:)
 

WizardG

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According to the specs from the aliexpress listing your laser is an over unity device with 5500 mW of optical output from only 4800 mW of electrical input. Neat trick! When operating, does the laser appear blue or purple? I'm wondering if you may have a 405nm BDR-209 type diode in that head. 600 mA would be about right for that diode but much too low for an N450 type 450nm diode.
 

WizardG

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A 450nm laser appears violet, a 450nm laser will look deep cobalt blue.
 

DrMario

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4.8 Watts electric (at 12 Volts) in for 5.5 Watts optical out is only possible with the properly designed buck DC-DC converter (switchmode buck DC-DC converter is actually far more efficient, only if you design it properly) - actually, you need to have 4.2 - 4.6 Volts at the blue laser diode at around 3.2 - 3.8 Amps (I am using Nichia NUBM44-81 6 Watts blue laser diode as a reference here) - why the variability? Simple, NO diodes are the same.

However, I have a feeling that it may probably have turned into dark-emitting laser diode, if not LED'd from the start. Personally, I would patch in ammeter on the laser diode connection to make sure it's getting the power as necessary (if you're not electrically inclined, don't bother as it's all too easy to kill the laser diode) before determining that the laser's on the last leg.

Lastly, is the laser light pure blue or with purplish tinge? If it's a bit purplish, it's 405nm violet - forget 5.5 Watts, as Blu-ray Disc 405nm laser diode have only recently hit 2 Watts in response to increasing writing speed of BD-R, the only way you can get that much light is by using Nichia NUBM44 450nm laser diode or equivalent. Otherwise, if it's pure blue, check the module - especially the size of the laser diode package, if you can remove the fan without destroying the module, see if you can see the gold TO-18 transistor package in the module. Blue laser diodes that are over 2 Watts almost always come in 9mm TO-18 package, not 5.6mm. If it's indeed 5.6mm, you have been ripped off.
 

WizardG

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4.8 Watts electric (at 12 Volts) in for 5.5 Watts optical out is only possible with the properly designed buck DC-DC converter
Ummm.... no. It doesn't matter what type of driver you use. You can not get more power out than you're putting in.

Add to this that if this is a NUBM44 type diode then the electrical input to get 5.5 watts out the lens will be around 20-25 watts.

I strongly suspect the OP bought themselves a BDR-209. Nice diodes to be sure. And great for cutting paper or light fabric in my wife's cutting machine (Silver bullet FTW!) but not really enough power for cutting wood.
 

DrMario

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Ummm.... no. It doesn't matter what type of driver you use. You can not get more power out than you're putting in.
Yes, it do. Trust me. The higher the input voltage, the more efficient the buck driver will be, otherwise how do you explain tens to hundreds of Amps throughout the modern CPU at 1.2 Volts or low while you only draw up to 5 - 10 Amps at 12 Volts? (For AMD Phenom II Deneb, 95 Amps is required at 1.25 Volts for decent performance. The way voltage regulator deliver that current to the powerful CPU is to have multiple inductors synchronously buck the voltage - you get a lot of current at the price of voltage. 95 Amps at full voltage of 12 Volts will vaporize the Pentium 4 voltage regulator plug cables instantly like a fuse, while at the same time, the motherboard makes overzealous amount of copper fill to handle that current going into the CPU without going up the smoke.)
 

diachi

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Yes, it do. Trust me. The higher the input voltage, the more efficient the buck driver will be, otherwise how do you explain tens to hundreds of Amps throughout the modern CPU at 1.2 Volts or low while you only draw up to 5 - 10 Amps at 12 Volts? (For AMD Phenom II Deneb, 95 Amps is required at 1.25 Volts for decent performance. The way voltage regulator deliver that current to the powerful CPU is to have multiple inductors synchronously buck the voltage - you get a lot of current at the price of voltage. 95 Amps at full voltage of 12 Volts will vaporize the Pentium 4 voltage regulator plug cables instantly like a fuse, while at the same time, the motherboard makes overzealous amount of copper fill to handle that current going into the CPU without going up the smoke.)

Power out CANNOT be greater than power in. It doesn't matter what sort of power supply you use. If there was a device capable of achieving that we'd need to toss everything we know about physics in the trash.

Take your example of a CPU.

Say it's running at 1.2V and 100A. Plug that into P=IV, that's 120W. Now, say the supply voltage to the CPU regulator is 12V, calculate the current using P=IV. P=120, V=12, therefore I=10A. The power is the same, the current and voltage however change but always result in the same (less in the real world, due to losses) power.
 
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WizardG

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Current=/=power. The spec sheet from aliexpress says the laser the OP bought puts out more WATTS than it consumes. Physics says NO.

With the efficiency of laser diodes somewhere around 20% his laser should use around 25 WATTS to pump 5.5 WATTS out the lens. Add in driver losses and this figure goes up closer to 30 WATTS.
 

paul1598419

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:pop:

I suspect OP has destroyed his LD and needs to replace it. It is most likely a NUBM44, which is a pretty cheap diode. See Ricker's site. Since you have now messed with the driver, it may need replacement also. Photos of the driver and diode would be helpful.

Edit: I see the drive on Ali Express. I am fairly sure you can find and order the driver there.
 
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WizardG

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I'm suspicious about the diode being used here. That both of the drivers the OP has tried are putting ~600mA through the diode makes me wonder if he has a BDR-209 instead of a blue diode.

Yeah, the spec sheet on aliexpress says 450nm, but it also says the laser puts out more power than it consumes so....
 

paul1598419

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Yeah, the Chinese don't know as much about what they are selling than they should, but I doubt it is the BDR-209 as the power they claim is not usually off by THAT much. I think it is more likely a NUBM44, but the size of the diode would answer this question easily. The BDR-209 is 3.8mm in diameter, while the 44 is 9mm.
 

WizardG

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Yeah, the Chinese don't know as much about what they are selling than they should, but I doubt it is the BDR-209 as the power they claim is not usually off by THAT much. I think it is more likely a NUBM44, but the size of the diode would answer this question easily. The BDR-209 is 3.8mm in diameter, while the 44 is 9mm.
If it's a '44 then it never worked correctly. The OP states the laser would "burn slightly" when new. A '44 running 5+ watts will do more than 'slightly' burn wood. :lasergun:
 

DrMario

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Fair enough on power supply. Maybe I need to review Texas Instruments switchmode power supply design handbook a bit more.
 
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