DIY 3000mW blue laser pointer — Burn solder wire at 8 meters

A video of burning solder at 8 meters

I bought a 3000mw laser pointer from LuckLaser and found two undesirable places:

1. Large heat, poor heat dissipation. This high power laser, Heat will certainly be great, But the cooling design is not good, The main reason is that the surface of the radiator is small, so heat conduction is not good, mainly concentrated in the laser head, the laser head is very hot but the tail not too hot.
2. The head screw is not tight, and there is a gap when focusing.
3. The lens is too small, still uses the traditional 10mm focal length, the absolute aperture 5mm, the relative aperture f2.0 universal lens

If you want to solve the heat problem, you must increase the head, increase the surface area of heat, of course, portability will be affected;

In addition, Blue laser divergence angle is big, it the need for a large relative to the aperture of the lens to do, The f/2.0 lens doesn’t absorb the light of the laser tube sufficiently, but also waste and heat. More importantly, the divergence angle of the laser is inversely proportional to the focal length of the lens. That is to say, the longer the focal length of the lens, the smaller the divergence. This requires us to use telephoto lenses and large aperture lenses.

Many photographic lenses are already available. If we make an interface, then a large aperture camera head can be used as a laser lens to solve the problem.

To connect the lens to the laser head, not only the interface can be screwed on the laser head, but also the lens is screwed to the interface.
There are many kinds of lens interface, I found a Nikon turn M52 lens ring ring:

The connecting ring, eBay search “macro reverse connection ring filter”, Nikon, Canon, Pentax interface etc..
In this way, Just find someone to process a lower interface ring.

Before assembly

Burning tin solder site, with 2 x 5.5 meter ruler, a measure of 5 meters, another relay 3 meters

Current – voltage – power curve
The horizontal axis is the battery voltage, the longitudinal axis blue is the current, and the red is the power, except 10.

In the voltage range of the double lithium battery (6V-8V), substantially constant power, output power of 13 watts, excluding close to 3W, so the heating power is 10W, not small.

Because the power is constant, the current is great when the voltage is low, 8V is 1.68A, but 6V increases to 2.18A.

Endurance time, basically no problem. Two 3Ah 18650 batteries can last more than 1.5 hours.

The reason for restricting laser continuous lighting is that the heat is too large, not only hot, but also more important to life.

Even if I add a brass head, it can be lit continuously for 5 minutes, and if it lasts longer, it gets too hot.

Intermittent life no problem, see me above second attached to the test chart.

Under the battery 8V, the current is 1.68A, but under 6V it increases to 2.18A.

The 445nm laser belongs to the blue violet light, which is usually passed by the lens coating.
The range of visible light comes from 400nm.
In order to prevent ultraviolet, general with UV light outside, UV is below 400nm.
Practical use, the output power is full, that loss is very small.
Despite the blue light from the lens, but it is mainly the outer surface of the lens glass dirty.