Are there definitely risks from welding fumes, if a robot is doing the job? Many welders ask this question. The almost completely automated process mainly hides hazards. A fume extraction system should always be installed with a hood.

Laser welding is an almost completely automated process. While guiding the laser beam, no human intervention is required. A robot executes the seaming of the parts without external intervention. Only the feeding of an additive into a sub-form is still done by hand today. Because of this virtually independent method of working, many welders ask the question: “Are precautions in the workplace definitely necessary if the robot is working on its own for all practical purposes?” The answer is emphatically: “Yes!”

Vaporization from the laser

As the methods of laser welding differ in their execution, various dangerous situations arise, depending on the process used. Vaporization from the basic material occurs during melting from the high energy input. This leads to the emission of pollutants in the form of light smoke. Their chemical composition equates approximately to the composition of the basic material being welded. The highest emissions arise while working with galvanized parts. When using a laser beam there is another difference – whether you weld with CO₂ – or a solid-state laser. With ideal settings, the latter releases fewer emissions than more conventional CO₂ lasers.

Hybrid methods create more emissions

The volume of smoke with laser hybrid welding is dependent mainly the method being used. This is often MAG (Metal Active Gas), but MIG (Metal Inert Gas) and TIG (Tungsten Inert Gas) can also be used. Because the output and feed speed are much higher than with conventional methods, lasers produce higher volumes of vapors than non-automated methods. When using aluminum, ozone is generated. Therefore, it is particularly important when using these methods to connect an extraction system directly to the source. The fumes have a high content of aluminum oxide which affects the lungs, can cause irritation of the respiratory tract, dust deposits in the lungs and irreversible aluminosis.

Laser deposit welding releases HAZMAT

This method is different to other methods, because in addition to the material being welded, either wire or powder is added to the mix. If it is powder, breathable particulates of the powder are introduced to the fumes formed. The composition of the smoke equates approximately to the chemical components of the additive and the material being used. For example, when working with cobalt-based alloys, the main component is cobalt oxide. With nickel-based alloys, nickel oxide or cobalt oxide are the main components. Both are carcinogenic. Iron oxide is released when joining steels with a high chromium content. This leads to dust deposits in the lungs – so-called “lung tattooing”. The total chromium content is mainly in metallic form or trivalent oxide form. Copper oxide is released with aluminum multi-content bronzes. This can lead to metal fumes fever.

A welding fume extractor is required

Without reasonable protection, the particles and materials emitted would flow into the production area and contaminate the air for the entire workforce. Accordingly, an effective clean air system is definitely needed. The size and type depend on the size of the robot and the parts to be processed. With small parts, a firmly mounted hood or one which covers the robot’s working area will suffice. If need be, this will move with the robot. Many businesses dispense completely with an extraction system or merely use area ventilation systems. They do this at their own peril. Due to the high energy used by robots, many unhealthy ultra-fine particles are produced and have to be controlled. A welding fume extraction system is therefore urgently required.