Nov 3, 2023

Towards a Revolution with Robotic Machining assisted by 3D scanning

Introduction

The benefits of using composite materials in numerous industrial sectors are well-established. Their advantages such as:

Strength,
Weight,
Durability,
Corrosion resistance,

make composite materials a prime choice for certain applications (Aeronautics, Wind Energy, Rail, Nautical, Space, etc.). However, their growing adoption raises a question: how to give them the desired geometry? How to machine them efficiently?

Traditionnal Machining Methods: Advantages and Limits

There are two main methods to date for machining composite materials. Depending on the application, whether in production or service, one or the other will be favored :

Manual Sanding : This method is very simple to impletment and adaptative with the human eye but has numerous limitations :
- 🚫 Imprecise: Entirely dependent on the operator's skill
- 🚫 Dangerous: Releases toxic dust
- 🚫 Arduous: Physically demanding
- 🚫 Inconsistent: Difficult to reproduce

Robotic Machining with Shaped Tooling : This method significantly overcomes the limitations of manual sanding by using a CNC machine but, in contrast to sanding, brings many new significant constraints:
- 🚫 Costly : Each shape requires its own tooling for part conformity. This has a strong impact on small series or large volume parts.
- 🚫 Not adaptive : Any variation in the shape of the piece requires a new program.

How to develop an intermediate solution that combines the advantages of each method while erasing their limitations ?

For a machining robot to adapt to a part not conformed by tooling, one must either:

- Adapt the trajectory continuously with active compliance. Active compliance implies low travel speeds so that the system has time to react, and therefore is suited for extensive processes like sanding.

- Adapt the trajectory to the actual geometry of the part by 3D scanning in the robot's frame of reference. For fine tools like milling, laser, or abrasive water jet, robotic machining assisted by 3D scanning is much more appropriate.

BAYAB Industries' Vision : Simplifying the Use of 3D Scanning to Optimize Tool-less Robotic Machining

BAYAB Industries has been innovating in the machining of composite materials since 2007. Indeed, the company developed and demonstrated the interest in abrasive water jet machining. The qualification/certification of this new process by AIRBUS and the French Air Force (AIA CF) for the bonded repair of composites proves its techno-economic relevance and robustness.

In 2020, BAYAB moved from 2-axis machining (without the need to adapt to the geometry of the part) to 6-axis machining (involving adapting the trajectory to the actual geometry).

BAYAB has therefore developed in-house the machines and software allowing for a complete system simple to use for scanning the actual part :

- Simply : The part is first scanned from a distance by a fixed scanner that locates the part in the robot's environment and provides its overall shape to +/-20mm (Figure 1 and Figure 2)

- Automatically : The global scan is used to automatically generate a precise scanning trajectory carried by the robot

- Quickly : The robot scans the part in 20min/m² (Figure 3)

- Consistency : The structured light projection scanner adapts well to all surfaces (matte or shiny, plain or textured, dark or light)

- Accuracy : The accuracy reaching 0.03mm is sufficient to control the machining of composite plies

- Intuitively: 3D scanners equipped with cameras capture color at the same time as geometry, simplifying the subsequent positioning of machinings (Figure 4)

Wide-angle 3D scanning of the robotic environment and the part — Figure 1: Meshing of the robotic environment by SYASCAN

Recognition or selection of the part after 3D scanning of the robotic environment — Figure 2: Automatic recognition or selection of the aera of interest by SYASCAN

Accurate 3D scanning with ARTEC carried by a Stäubli robot — Figure 3: Accurate robotic scanning controlled by SYASCAN

Digital display of the 3D scan with texture of the part — Figure 4 : Display and processing of the textured digital twin of the part by SYASCAN

Examples of Use: :

Repair machining of a wind turbine structure for ENGIE GREEN

Robotic cell assisted by 3D scanning for machining wind turbine blades

Repair machining of a removable part of a military aircraft

Machining of composite plies on a military part

Production machining to smooth the shape of a composite mold

Smoothing of a composite mold by abrasive water jet robotic machining

Conclusion

In conclusion, the world of composite material machining is on the brink of a revolution. BAYAB Industries' innovation in robotic machining assisted by 3D scanning not only promises significant improvements in accuracy and efficiency but also ease of task execution for operators.