The Manufacturing Process
Air bag production involves three different separate assemblies that combine to form the finished end product, the air bag module. The propellant must be manufactured, the inflator components must be assembled, and the air bag must be cut and sewn. Some manufacturers buy already-made components, such as air bags or initiators, and then just assemble the complete air bag module. The following description of the manufacturing process is for driver-side air bag module assembly. Passenger-side air bag module assemblies are produced slightly differently.
Propellant
- The propellant consists of sodium azide mixed together with an oxidizer, a substance that helps the sodium azide to burn when ignited. The sodium azide is received from outside vendors and inspected to make sure it conforms to requirements. After inspection it is placed in a safe storage place until needed. At the same time, the oxidizer is received from outside vendors, inspected, and stored. Different manufacturers use different oxidizers.
- From storage, the sodium azide and the oxidizer are then carefully blended under sophisticated computerized process control. Because of the possibility of explosions, the powder processing takes place in isolated bunkers. In the event safety sensors detect a spark, high speed deluge systems will douse whole rooms with water. Production occurs in several redundant smaller facilities so that if an accident does occur, production will not be shut down, only decreased.
- After blending, the propellant mixture is sent to storage. Presses are then used to compress the propellant mixture into disk or pellet form.
