Case study showcases the successful use of professional 3D printing and high-performance composite material in the manufacturing of an airbag housing container
For over a century, Joyson Safety Systems has been innovating mobility safety, bringing life-saving technology to customers worldwide. It designs, manufactures and sells safety products, such as airbags, seatbelts, steering wheels and safety electronics.The firm was the first manufacturer supplying series steering wheels with a ‘hands-on-detection’ (HOD) function for autonomous driving to renowned OEMs in North America as well as in Europe.
Recently its Core innovations team started a project to explore and deep dive into the additive manufacturing field, also pointing out its possibilities and potential to discover new processes and materials to use for the manufacturing of an airbag housing container.
They therefore carried out a market analysis to discover a composite material corresponding to the existing material (in this case, polyamide with 40% glass fibre reinforcement) used in production of the airbag housing container through conventional process (injection moulding).
The driver airbag (DAB) housing part is often produced with PA6-GF40 material. The complete system of the airbag is consisting of inflator, an airbag cushion, a cover and a housing with attachment points on the steering wheel. The airbag cushion that is connected to the housing part is located within the space of the housing and the cover.
The performance of the DAB housing part is extremely essential, due to the fact that it’s a safety component in the vehicle. This means that the airbag will inflate during a sudden accident within quite a short period of about 30-50ms to prevent the passenger from any injuries. The DAB housing holds the entire airbag system in place so it is also a base essential component for the system.
Samer Ziadeh from Joyson Safety Systems’ Core innovations team explains the function of the DAB housing, and says that “it is to withstand a high amount of dynamic loads in addition to holding the inflator and the airbag cushion fixed in location during and after the deployment of the airbag system. This load is developed due to the pressure required to inflate the airbag, as a result the large stresses will directly be applied on the airbag system and more particularly on the DAB housing. The test procedures are normally conducted within a various range of temperatures between -35°C and 85°C.”
It’s a given then, that the material used for manufacturing the part is expected to have sufficient strength, impact resistance and heat stability to perform properly under different testing conditions.
Testing composite materials with the DAB housing
The team scheduled a very tight programme, aimed to reach specific purposes, that is: produce a real functional prototype part within days instead of months, out of composite materials that are almost similar in mechanical, thermal properties and performance to the original materials; test part performance under real testing environment conditions to examine how the material will perform under thermal changes and to withstand high strain mechanical stresses; eliminate the amount of time-consuming and avoid the highly tooling costs of conventional process.
The team turned to CRP Technology for its Windform Top-Line range of high-performance materials and its in-house 3D printing service. Ziadeh comments that, “after running some market analysis to find out the most suitable material and process that could deliver the required performance, we came across the Top-Line family of composite material and, specifically, the Windform SP. The range caught our attention due to the fact that it’s a material produced from polyamide PA grades and reinforced with carbon fibre as a powder form material, and it has almost the required and even better performance for our application.”
“The technical data of the Windform SP displayed a very high potentials to be used for producing the DAB housing by SLS process, says Daniel Alt from the innovations team.”
Thanks to the collaboration with CRP Technology and to the use of Windform SP carbon composite material, it was possible to produce a functional prototype and to test it in a complete airbag module within a short period.
Collaboration between CRP Technology and Joyson Safety Systems a success
The test has led to very good results as the material exhibits an excellent mechanical performance in terms of high strength and impact resistance as well a good thermal stability between a low and high range of temperatures (RT; 23°C, -35°C and 85°C). “Therefore this opportunity has opened up a variety of capabilities and considerations for a further cooperation with CRP Technology,”comments Ziadeh.
Alt adds, “Also, the prototype part demonstrated an outstanding performance during various testing conditions, which has proven the fact of part functionality for a complete consideration of a new product development. Basically, the advantage of using the SLS process is the possibility to use reinforced polymers with high mechanical performance and stability. The combination allows for the manufacturing of complex part structures with good tolerance. The Windform SP indicates an excellent mechanical properties in terms of high tensile strength, impact resistance and thermal stability at high temperature. This actually fulfils the requirements of the DAB housing part.”
The most innovative aspect about Joyson Safety Systems’ project and application is the fact that this is the first functional prototype of a DAB housing to be produced with SLS process using a composite material that exhibits an excellent mechanical performance in terms of high strength and impact resistance as well a good thermal stability.