Help i need constant current driver for my IR CNC project.

[laseraddict]

Hi guys, can anyone help me? I recently purchased two very powerful IR lasers for my engraving project. Guys that i've got the items from told me that i could run them from my MASS bench top power supply. I'm kind of reluctant to do stuff like that since these lasers cost absolute fortune. One is 8W IR, and second is 20W IR with Peltier passive cooling system. 8W needs 2V at 0.7A constant current. Also i heard about divers that can turn of light emission without turning of laser diode, these are apparently used for laser shows.
Can anyone advice me how to built driver like that? I know you can guy them but they cost arm and leg! And one more question, what is TTL in laser terms, I know this term from photography but I don't know what's that got to do with lasers.
Thank you.

 

[Things]

I'm kind of amused that he said you could power a 8W laser diode from only 1.4W input. Are you sure he hasn't scammed you for a lower powered diode? Because no way you'll get even remotely close to 8W from 1.4W input.

 

[laseraddict]

Hi thank you for reply. Here are the items i bought. See what you think.
Fiber-Couple laser Jenoptik diode laser 808nm 20watt cw 20w diode laser | eBay


Laser Diode 8W 8 Watt 8000mW 915nm Fiber Coupled 100UM Multimode Pump New | eBay

 

[laseraddict]

I'm quoting his reply here.
"Thanks for your order. All laser diodes need a current
regulated power
source. If your bench supply has a current adjust knob,
it will likely
be able to safely power this laser diode. A proper laser
diode driver
has a number of safety features that a bench supply does not
and so I
recommend the following procedure for powering a laser diode
from a
bench supply.

- start with the laser diode disconnected from
the power supply.
- turn on the power supply and set it for about 3V and 0
amps
- make sure the diode is attached to a good heat sink. It will
overheat
in seconds without one!
- connect the laser diode to the power
supply. Be sure to get polarity
right - the pin on the diode which is
connected to the body is positive
(i.e. positive ground)
- slowly turn
the current up being very careful not to go higher than 10-12A

To power
down

- turn the current to zero
- disconnect the laser diode from the
power supply before powering it off

Many power supplies produce a surge
of current or voltage when being
powered on or off which is why I
strongly recommend never cycling power
while the laser diode is
connected.

 

[laseraddict]

:yabbmad:Hi again. I've got some details wrong, my 8W needs around 3V at 7amp. And silly me i just noticed that for my 20W guy gave me wrong spec sheet. He gave me one for 40 Watt.
Yet still I need to get driver to run them safely. Anyone can help?

 

[Cyparagon]

The beam/spot will be rather large. Your CNC will have poor resolution, wide cuts, and make lots of smoke. I suggest you look into CO2 lasers instead.

 

[laseraddict]

Hi. Thank you for suggesting CO2. Friend of mine he's got set up just like i want to achieve. And with fibre optics his little machine does beautiful work. CO2 set up is way to big for what i need. I have limited space in my workshop. That's why i want to go for laser diodes. Anyway thank you for your reply.