Dear Marius Andreas,

Depositing money on the glass (lens) when working with an SLS machine is a major problem. To reduce this problem, a protective environment is created to protect the lens. The gas may be Ar or other non-combustible gas which is delivered in front of the lens with a working pressure of 0.4 to 0.6 bar, different from the working pressure in the chamber or medium.

Applying protective coatings helps to make the lenses smoother but changes the performance of the laser. However, this is an inevitable effect.

Regards Emil Yankov

Dear Emil Hristov Yankov,

thank you very much for your answer. The biggest problem is the vacuum. The pressure in the chamber is less than 0.1 Pa and the gas flow must not remove the vacuum.

Best regards

Marius Andreas

Why not using an adhesive transparent film which can be easily removed and substituted by a new one?

Dear Sergei Tarasov,

thank you for your answer. The glass must be kept clean during the wlole working process. Afterwards, we could change even the glass. The process can take several hours, maybe up to 30 h.

Best regars

Marius Andreas

Depending upon the electron beam energy there is part of plasma and part of metal vapor. Plasma could be removed by using an electrocharged filter. Also using a system of magnetic lenses the electron beam may be deflected so that the most part of the vapor settle on some other victim surfaces while the glass window stays out of the vapor flow reach. It's a bit complicated way but as far as I know electron beam may be deflected at an angle as high as 270 grad if needed.

Thank you. I don't know about the amount of plasma in this process. However, the glass must be in line of sight to the melting pool.

We have similar problem.

In your case, glass is polluted by vapor or tiny particles ?

Have you found a solution yet ?