(Translation of German websites)
Cobots are considered flexible and inexpensive. This is why small and medium-sized companies like these machines. In many cases, cobot systems don’t even need a safety fence. But what about arc welding? We’ll show you what to look out for.
Traditional industrial robots are often considered unsuitable for small and medium-sized companies. As a reason often the supposedly high acquisition costs and the qualification of the staff are named. The situation is different with collaborative robots, the so-called cobots. They are usually ready for use within a short time without any programming knowledge. The limitation of force and pressure during contact even allows operation without a safety fence in many applications.
There are also arguments for the use of cobots in arc welding:
- Simple programming by hand guiding at workpiece
- Automated welding even with small production batches
- Pulling out skilled workers from monotonous welding work for higher-value tasks
- Creation of attractive jobs by dealing with robots
- Removal of employees from long-term sources of danger
- No need to hold the welding shield for hours (ergonomics)
But can the cobots also be operated without a fixed guard (hood, cell) during welding? To answer this question, you have to deal with the risks. According to the German Berufsgenossenschaft, these are, for example:
- Inhalation of hazardous substances, e.g. welding smoke and welding dust
- Electro-ophthalmia of the eyes due to optical radiation
- Burns caused by welding spatter and hot components
- Fire or explosion caused by flammable substances
- Puncture or crush injury caused by the robot
- Noise hazard from welding nozzle
- Electrical hazard due to welding current
The Machinery Directive 2006/42/EC stipulates that machines shall be equipped with safeguards to minimize the above-mentioned risks already when they are placed on the market. Therefore, according to the current state of the art, it is obviously unavoidable to equip cobots for arc welding with safeguards, e.g. hoods or cells. When accessing or entering the work zone, the hazardous processes shall also be stopped. The manufacturer marks the fulfilment of these requirements with the CE mark.
By the way, cobots should not be compared with hand welders. According to European law, cobots – even if they are designed to collaborate with humans – are fully comprehensive machines. In arc welding, the so-called fence-less operation of cobots is therefore less relevant in automatic mode but more beneficial for path programming. The hand guiding of the cobot at workpiece offers great potential.
For more information on safety requirements for industrial robots and cobots, please refer to the standards EN ISO 10218-1 and EN ISO 10218-2.
