For my laser experiment I am using collimators from old laser printers and copie machines. Especially from copiers.
A collimator is a device that narrows a beam of particles or waves. To “narrow” can mean either to cause the directions of motion to become more aligned in a specific direction (i.e., make collimated light or parallel rays), or to cause the spatial cross section of the beam to become smaller (beam limiting device). (source- wiki)
These devices are adjusted for copying process and IR laser. Meanwhile I need to use other settings. It is quite difficult to do this, as everything is very stiff and glued with some warnish.
First of all, remove all the parts if it is possible. Especially all plastic parts.
All we need to get metal cylinder with real glass optics:
Now slowly heat it with hot air gun or even using flame from stove. Everything in this model of collimator is heat proof. When warnish softens, just unscrew the rings. Do not touch the glass with your finders- it will stain the surface. Also, the glass will be very hot, do not drop it to cold surface.
Do not forget the sequence of glass elements.
The remaining metal parts must be burned to remove all the remains of varnish. Here it is placed in burning gas stove.
As there is no glass parts inside, just drop hot metal part to water. Heat-cooling stress will loosen all the threads.
Wipe all the parts clean, remove varnish particles. Use just a bit of petrolium oil on the screws.
Here is the schematics of the collimator, for those who forgot how it was placed.
Is everything is OK, you must see enlarged laser crystal when looking to the end of collimator. Never stare to laser.
BTW, this collimator is optimised for IR laser, but works fine with red laser. Best laser collimators for red laser are in magnetooptical disk readers/writers.
Laser copy machine collimators like in these pictures can handle significant ammount of heat, so laser beams can be very strong.