Combing two 500w 405nm diodes to increase burning power

[Waka]

Hi,

I'm considering buying a MicroSlice kit, which is a miniature laser cutter/engraver that uses one 500mw 405nm laser to do the cutting, and a 3 element glass lens.

I'm interested in increasing the power of this by using two of these diodes and a PBS cube (Which I read about on another thread in this forum).

The effective focal point through the lens is 8.3mm, and without the lens the diodes focal length is 3.1mm.

My question is, how far away from the pbs cube are the lasers mounted, and how far away is the burning point from the pbs cube, the focal point of the standard diode?

Thanks,
Waka

BTW I'm new here, hi!

 

[diachi]

The diode wouldn't have a focal length ... Focal length is a property of a lens. Distance to focal point with lens/diode is likely going to depend on how you have the lens adjusted - most diode modules have adjustable lenses, and thus adjustable focal points.

You can mount the diodes just about as near or as far from the PBS cube as you want ... I'd probably aim for 10-20mm.

Best way to do this with a PBS and two diodes is to focus both diodes to infinity (Collimate them), combine them with the PBS and then focus them with a separate focusing lens after the PBS cube.

 

[Eracoy]

If you want to combine only at 500mW each, might I suggest a single 900mW+ BDR-209 diode? I have several and they work great as very nice single mode blu-rays.

 

[Waka]

The diode wouldn't have a focal length ... Focal length is a property of a lens. Distance to focal point with lens/diode is likely going to depend on how you have the lens adjusted - most diode modules have adjustable lenses, and thus adjustable focal points.

You can mount the diodes just about as near or as far from the PBS cube as you want ... I'd probably aim for 10-20mm.

Best way to do this with a PBS and two diodes is to focus both diodes to infinity (Collimate them), combine them with the PBS and then focus them with a separate focusing lens after the PBS cube.

Thanks for the reply, ah that's interesting, how would use a lens after the cube? The only ones I've seen are threaded and screw in to a casing around a diode.

 

[Waka]

If you want to combine only at 500mW each, might I suggest a single 900mW+ BDR-209 diode? I have several and they work great as very nice single mode blu-rays.

Yes I just saw these, I'm thinking of combining 2 of these now to make a nice 1.8w laser cutter which should cut 2mm ply relatively fast.

 

[Pman]

I would wonder about how long those diodes are going to last at that output. My bet is you will be replacing them often unless you have some serious cooling. 2 at 500 each or 1W total sounds much more doable to me.

 

[diachi]

I would wonder about how long those diodes are going to last at that output. My bet is you will be replacing them often unless you have some serious cooling. 2 at 500 each or 1W total sounds much more doable to me.

Yeah, you bet me to it. Wouldn't be surprised if the 500mW diodes you're looking at are BDR-209s but running more conservatively in order to achieve a longer lifespan.

 

[Waka]

Thanks for the info guys, I'm thinking of making the initial design using a 900mW single diode with a 3 element lens to begin with as these materials are quite cheap.

Instead of buying the kit though I'm going full diy.

I'm thinking of building it inside a PC tower and fitting multiple case fans.

I'm actually looking at some designs for SLS 3d printers that use the same laser and may be able to be used for both purposes