A low cost 40W continuous blue laser

Caution: this a dangerous project: safety goggles absolutely required !

Here is a low cost (less than 500$), powerful (40 Watts continuous), visible ( blue 445 nm) laser

The key component is the blue laser module from a Casio XJ-A140 video projector blue laser source. (I bought my Casio second hand working XJ-A140 for less than 400$ in France)

This source is made with 24 x 1.5 Watts 445 nm blue laser diodes installed on a heat sink, 3 fans. Each laser diode is collimated, then each beam is reflected on a Jacob's Ladder mirror in such a way all 24 parallel beams are directed on a lens which focus it on a single point. It allows to melt stones...

In the Casio laser module, there are 4 electrically independent groups. Each group is made with six 1.5 Watts 445 nm laser diodes daisy chain connected.

All that is connected through a soft printed board and a miniature SMD connector to the Casio controller print board. Plus 10k thermistor control, 100°C security switch...

It's very difficult (for the amateur) to connect to the SMD miniature controller.

So we choose an alternate way: on the soft printed board, for each of the four groups, there is a protection diode (probably a Zener diode to protect laser diodes from electrostatic discharges.

On each of these four diodes we connect two wires. These 8 wires are connected to a standard 9 pins female SUBD connector Through 4 x 5W 1 ohm power resistors.

Pins 1 2 to ground, pin 3 for fan, pins 4 5 for Vcc. other pins free for future.

(Note that this way allows to reuse the optical laser module in the XJ-A140 if necessary...)

And we use a 2 m mains cable equipped with 9 pins SUBD (1 male and 1 female) connectors to connect to the PSU (Power Supply Unit) to the module:

From Left to right:

CD (just for scale)

The output lens

Heat sink (no fan on the picture)

Jacobs Ladder mirrors are on the top, below is soft PCB with protection diodes and wires

On the back is SUBD 9 pins male connector connected to the four diodes power resistors

and the standard 9 pins SUBD cable.

Here is a more detailed pictures inside Casio laser module:

The slim XJ-A140 video projector itself:

The 24 x 445 nm laser diodes: 4 groups with 6 laser diodes Daisy chain connected so there are 8 wires (plus temperature sensors)

Each of the 24 laser diodes beam is collimated with it's own lens:

Jacob's ladder mirrors arrangement to send 24 // beams to the output lens (such a mirror arrangement isn't very easy to do for an amateur: here job is done :-) :