If all claims are exact (which on ebay from chinese sellers is a gamble), theh 405nm 1500mW will greatly outperform the blue laser.
That being said, thhe blue laser module has a driver, fan, heatsink included all in oone. The single 405nm diode does not, and you will need to purchase those seperately.
If it were me, I would DIY all of the parts, because theres NO WAY it's worth $240 USD for a 2W blue engraving kit.
PM me if you want me to build you one for half the cost.
Thanks. Could it be that chinese interest$ hide which published milliwatts are electrical consumption and which are optical emission power ? Telling the truth could impair sale$, right ?
The one with heat sink/fan has the exact same12mm module inside. There is no room for a driver board unless inside the 12mm module. Is it there ? Do the 12mm modules have a driver circuitry built-in or need the external driver board ?
IIRC, In years past, eBay would quickly take down listings for lasers above 5mw. Might have just been for pointers but I remember for a long time you wouldn't see a power rating listed in the title. They seem to have relaxed that policy in the last 5 or so years due to the growing number of applications for lasers in manufacturing. Now you see over exaggerated power numbers because chances are someone will be dumb enough to buy it.
Also why 405nm specifically? That's an unusual wavelength for engraving.
For industrial use, it is understandable marketing higher powers, if they are true figures. About 405nm; you know more than me. 405 shows more for engraving, at least on ebay. What would be preferred ?
How much do you want to spend? LOL. The obvious choice would be CO2, followed by 1032 Nd:YAG. If the material you are working with responds better to UV light then you would just select the third harmonic from the Nd:YAG via frequency conversion.
There is nothing wrong with 405nm, per say, but if you are trying to make an engraver from scratch using diodes then, dollar-for-dollar there are better options. Coupling two NUBM44's and you are already close to 15 watts of power. There are also 808nm & 915nm fiber coupled modules that put out scary amounts of power. You can easily find 808nm packages that push 300 Watts for sub $2k.
Forewarning - at these power levels you better have CERTIFIED laser safety glasses with a proper OD # determined from the ANSI Z136.1 standard.
The one advantage of some of the 405 diodes is that they're single mode so they can be focused to a much smaller point for very fine engraving work. If you wanna do laser scrimshaw they're the way to go.