Lufthansa Technik

150 and counting: The manual process was both tedious for the workers and prone to unnecessary redundancy.

If the robot takes over the thread inspection, the work requirements of the mechanics are reduced to comparatively short set-up times, which in the exemplary application above only take up four to five minutes of their time. Time that my colleagues can now use for activities with higher added value, such as the diagnosis of components. Here, they can exploit their enormous expertise, with clearly positive effects on value creation and efficiency. The use of the robot thus improves quality even further. On the one hand, it inspects every tapped hole with consistent precision, which has led to a significant positive development in both quality and throughput times compared with the previously manual process. Secondly, the robot can immediately convert the data collected during the inspection into a „digital twin“ of the inspected component, creating a basis for further forward-looking maintenance measures, for example for „predictive maintenance“ applications.

The classification as a co-bot enables the use on a mobile table that can be positioned

The design as a system in which man and machine „coexist“ (see graphic above) also enabled us to design the robot as a mobile system. It is only permanently connected to the rotary table on which the work pieces to be machined are placed and can be rotated 360 degrees around their central axis. At 1,200 x 1,400 x 1,700 mm, the robot and table unit are so compact that it can be rolled to any desired location in the workshop with great flexibility.   Despite the definition as a co-bot and the associated degrees of freedom for interaction with mechanics, we could not completely dispense with suitable measures for safe operation in a workshop otherwise „populated“ by humans, even with CoBot 2 DAT.   As a result, appropriate safety measures were implemented for the robot as well as for the rotary table and the screwdriving tool. The potential risk of people crushing or bumping into the robot was countered by reducing the traversing speed to a maximum of 250 millimeters per second. This also prevented jamming in the rotating component, as the rotary table only moves at less than one revolution per minute. In addition, the rotary table is driven without a brake, so that in the event of an emergency shutdown human operators can easily reverse it manually to prevent further damage. For the test tool, the maximum permissible pressure was also limited to 110 Newtons per square centimeter, which is monitored by appropriate force sensors. In addition, we have provided the screwdriving tool with a special protective cover. In general, it can thus be said that the Co-Bot also enables a high degree of flexibility and adaptability in this aspect. Its built-in vision system also brings the advantage that it can react very well to changing component conditions. Despite all this flexibility, mechanics must receive special training in which all the necessary protective measures are explained, as this is the only way to prevent a small residual risk.

Close-up view of the screwdriving tool and the built-in vision system.

All questions concerning safe operation in human-robot coexistence were therefore discussed extensively by me and my colleagues with all the responsible bodies of internal co-determination, for example the works council and its committees for occupational safety or IT. Among other things, we had to clarify the relevant liability issues when dealing with the Co-Bot. Our partner 3D.aero was also able to contribute its extensive expertise in this area.  

Conclusion and outlook:

  My colleagues in the workshops are unanimously positive about the Co-Bot, and not only because of the active involvement of all those involved. Those in occupational safety and quality assurance, as well as robotics experts and mechanics also provided promising feedback. The cooperation with 3D.aero as experts for innovative automation and digitalization of complex production and maintenance processes was also very positive and provided important impulses. Since the Co-Bot is also comparatively inexpensive to procure and intuitive to program, the CoBot2DAT project was also economically convincing, which is why the thread inspection has now been transferred to series use in the Hamburg engine workshops – as the very first Co-Bot ever in this business area.