One of the most laborious, manual processes in the composites industry is edge sealing. It’s repetitive, requires a lot of focus, it’s quality sensitive and leads to physical strains for the human worker. Nobody really likes to do this job. So why is not yet automated?
Let’s explore a new automated solution that we developed which addresses this problem: Automated Edge Sealing.
Edge sealing, why?
Composites parts commonly have to be trimmed after a moulding process to achieve a high accuracy part contour. This trimming operation is often a milling operation and it exposes the edge’s laminate structure and fibres to the environment, which can be an entry point for moisture into the part or be a source for galvanic corrosion when the part is in contact with metal structures. As moisture ingress or corrosion can compromise the structural integrity of the part, sealing the edge of a composite part is critical to prevent degradation and prevents the reduction of mechanical properties in the long term. This is especially important in the aeronautics industry, where durability and safety of any structure is critical.
Why is process not yet broadly automated?
Edge sealing is still a major manual process step that is not automated and remains ‘bucket and brush’ even at the most sophisticated manufacturing sites in the aeronautic industry. There are several reasons and challenges why this process remains very manual, such as:
- A large variety of geometrically complex parts that require edge sealing is common in aeronautics, which makes automation and programming with conventional methods virtually impossible because of prohibitive amount of programming hours
- High precision and automation of the dispensing equipment is needed to meet the requirements, as usually there are strict tolerances on the resin thickness
- For accurate dispensing, one normally needs accurate support tooling which can be expensive. In a manual process, the operator relies on his/her eyes and doesn’t need an expensive fixture.
- Resins are challenging to handle, commonly used two-part resins are highly viscous and have to be mixed with a precise ratio, which can be prone to human error if done manually. The resins cure quickly, and have to be mixed just before application.
Overcoming these challenges has a high gain: an automated edge sealing process that has the capability of saving labor and material, increasing quality and therefore reducing scrap parts or reworks and taking away the manual work that no one really likes to do.
How has Airborne solved the challenges?
Derived from Airborne’s mature technology Automated Honeycomb Potting and using it’s Automated Programming software, Airborne has developed Automated Edge Sealing that addresses the abovementioned challenges of automating the edge sealing process:
- Automated Programming, a proprietary Airborne technology: the 3D part geometry is translated into robot code and process settings directly, which eliminates the need for robot programming and provides maximum flexibility to the user
- A fixture-free process: the parts are identified by vision and the robot movements and process settings are adapted on-the-fly to create the perfect sealed edge. No fixture required.
- A sealing technology is developed that can seal parts with variable thickness, complex geometric features, holes and edges at an angle
- The right dispensing technology enables mixing the resin and hardener on the fly, whenever it is needed and provides highly accurate dosing for getting the right resin thickness
For the resin dispensing, Airborne teamed up with Viscotec, a specialist in high-accuracy dosing equipment. The collaboration started at JEC 2018, and together the companies are leading in advanced automated dispensing systems for composites.
In the chart below, a comparison is made between traditional offline programming approach and Airborne’s automated programming approach. A large amount of effort in work preparation, process engineering and robot programming is not needed anymore. There is a direct, autonomous workflow from design to robot code.
How does the system look?
A possible setup is shown below, however other variations are possible, such as the methods for loading the parts in the system. Depending on the customer needs, it can be adapted to specific parts.
The process starts with loading the parts on a conveyor belt. The parts can be in any orientation or position, the only condition is that they should have one flat surface. That is why support blocks are used. A camera recognizes the part and the location, and the algorithm provides the instructions for the robot to pick the part safely and to manipulate it at the resin dispensing unit. For accurate positioning, the robot is recalibrated on-the-fly for every part, which removes the need for expensive fixtures. The accurate dispensing system ensure that the part is sealed and then is offloaded from the system, ready to be cured in an oven if needed.
What are the benefits and why you think in adopting it?
There are numerous reasons to adopt an automated system for edge sealing. Typical suspects are: increased quality, reduction of production costs, health and safety and environmental concerns. But let’s review them in detail and uncover the main and secondary benefits:
Increased and constant quality due to a programmed, repeatable process with limited to no human intervention
- Costs due to non-quality or reworks are reduced
- Quality control inspection and digital documentation are an additional reduction in cost. In general, the more stable the process is the quickest and less control is needed.
Reduction of production costs at five main levels
- Labor: operators that work in the manual process can be up-skilled as users of the automated system or relocated into other higher added-value operations, which has a positive effect on the margins of the business
- Material usage reduced along with the consumables, which has a direct impact in both the material cost and the disposal cost of chemical waste
- The system enables the use of bigger resin containers, which are typically less expensive than small cans or cartridges, sometimes by a multiple of four to six times
- Reduction of non-value added operations, like mixing or tools and part cleaning, making the process more effective and less costly
- Process time is reduced, enabling the production of more products in the same timeframe or the chance of absorbing production peaks
Improving the operator work conditions
- Limited, reduced exposure to chemicals
- Manual intervention reduced to mounting the part leads to achieving suitable workplace ergonomics more easily
- The laborious, cumbersome sealing step that creates physical strain is avoided
Improving the environmental impact of your factory
- Less resin is scraped due to the on-the-fly mixing head, reducing the chemical waste
- Consumables such as disposable mixing containers or brushes are eliminated from the process
- Personal protection equipment is reduced as the operator does not get in direct contact with the resin regularly
Ready to be deployed
The first system is being developed and to be deployed at Cotesa GmbH, for a running commercial aircraft programme. This is a typical example where this system makes a lot of sense: shipsets with many different parts, currently all sealed manual by a large team of workers, which need to trained and skilled for this job and who experience physical problems caused by the repetitive nature of the work.
Reach out to us!
The technology can be used with any trimmed composite parts, being prepreg, dry fibre or thermoplastic composite parts. If your company has similar needs and wants to automate this process step, reach out to us to discuss how can help you with this technology.
If you want to know more or contact us, check out our website page on Resin Dispensing.
This blog was also posted on LinkedIn.
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