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cheap 2.5W laser: fake?

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Hello guys,

I recently bougth this cheap 445nm laser (~50$) for a laser cutter project:

https://www.ebay.fr/itm/Focusable-2...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

It is really inexpensive, and I'm a bit suspicious about its power. I'm new to the laser world, and I don't have good comparison figures to detect if it is a real 2.5W laser.

I was expecting to be able to cut 3mm of soft wood, but when I tested, even after 30s focused on the same point, I only had a 2mm hole, whereas I watched video of guys with 2.5w 445nm lasers cutting this kind of wood with few passes at 1mm/s.
I measured the current consumed by the driver : at 12V it eats 0.6 amps. It seems low for me, I was expecting around 2A, but still, I'm not sure if this value is ok for a 2.5W 445nm laser.

What do you think guys. Is it a real 2.5W laser according to your experience with other laser of this type?

Thank you for your help!
 
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WizardG

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First, I hope you're wearing safety glasses any time you have that laser powered up.

Second, completing your profile and introducing yourself in the 'Welcome" section is much appreciated and people will be much more willing to help you.

Third, 7.2 watts in for 2.5 watts out doesn't seem too unreasonable....until you subtract driver losses, lens losses....you get the idea. You probably get about 1-1.5 watts out the business end of that unit. Good enough for a fabric cutter, or paper. Not so good for wood as you'll have very slow cut rates and thick charring at the edges of the work.

Hope this helps. Welcome to the forum. There is a lot of good information here. Learn and make a few friends. You may be able to get someone here to take on the task of replacing the diode in your laser with something a little hotter for a few $$ if you ask reaaaal nice.
 
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Bacon

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Next time it might be telling if you ask them what type of diode is used. If they don't know than thats a bad sign. If its 450nm than maybe its a PLTB450B diode?? No way to tell for sure without checking it.

There are some members here that might be willing to measure the output for you. Other members also sell LPMs ranging from $75 and some for $400 they are pretty decent.
 
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paul1598419

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This was sold as an engraving unit and not for cutting. If you want to cut, the most important aspect is the power density of the beam profile. You want to get the most power into the smallest dot possible. For multi-mode blue lasers this is not easy to do. If you want to buy something to cut wood with, you should look for a laser that is designed to do that.
 

deadshadow

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im guessing that is using an m140 diode at best considering the low price so it would range around 1.5w+.if the front lens can be unscrewd you can take a picture of the diode and we can be much closer to our guessings ;)
 
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paul1598419

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Sure, it could be an M140 or even a used NDB7875. Regardless, it isn't going to cut wood no matter how much you want it to.
 
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Thank you all for your nice welcome :)

I hope you're wearing safety glasses any time you have that laser powered up
Yes of course, I even have waited for my super expensive glasses (40$) because I wasn't confident with the cheap one I already had ^^. Thank you for caring for my eyes ;)

completing your profile and introducing yourself in the 'Welcome" section is much appreciated
I will try to do it ;D

You probably get about 1-1.5 watt
Not good :/

You may be able to get someone here to take on the task of replacing the diode in your laser with something a little hotter for a few $$ if you ask reaaaal nice.
That is a really cool idea. In fact I am even more interested to learn how to do this! :D

If they don't know than thats a bad sign
I asked the seller ... but he wasn't able to answer me: "it's secret, others steal our design", "really good quality, no problem", "I'm only a seller, I don't know" ^^

Other members also sell LPMs ranging from $75 and some for $400
That's interesting to know, but for now I don't plan to buy one.

This was sold as an engraving unit and not for cutting
This was also sold as a 2.5W laser (all there products have the same generic description ^^), and according to my research, this power at this frquency should be enough to cut few mm of soft wood.

multi-mode blue lasers this is not easy to do
I didn't know that, it is a good point. Is there a way to recognize them, because I never saw such an indication on lasers I looked at.

if the front lens can be unscrewd you can take a picture of the diode and we can be much closer to our guessings
Here it is! :)


https://drive.google.com/file/d/0B7rqj26rA39hQ3lSMnBfYU9CZGd6UkVXZGZLM0hKSjg0WlA0/view?usp=sharing

I'm not sure if you will be able to say somethink with only this...
I also unscrewed the back to try to remove the diode, but unfortunatly it seems to be glued. I could maybe try to use my hot air gun, but I don't want to break everything ... not yet ^^

Sure, it could be an M140 or even a used NDB7875. Regardless, it isn't going to cut wood no matter how much you want it to.
Which not expansive diode would you recommand? Are there some comparative threads already existing for such high power diode? (I saw one, but only with low power diodes)


Thank you all for your nice help :) !
 
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hakzaw1

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looks like you need 'hands-on' help-BUT until you finish your personal profile we have no clue where you are???

and yes--MAKE an 'into' thread and place it the 'WELCOME' SECTION--see the ones already there for help..
 




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