The challenges involved in testing airbags

Why are airbags difficult to test safely?

Airbags are classified as ‘electroexplosive devices’ meaning that they detonate using an electric charge. This means it is too dangerous to simply connect traditional ohmmeters to an airbag to see if the electrical connection is correct.

During the manufacture and assembly of vehicles where airbags are fitted, it is important to ensure that the wiring harnesses are connected correctly to any sub-assemblies that contain these airbag units.

Failure to do this could require significant rework, slowing down the production line or needing a separate major rework process in place.

Solving these issues

By using ultra low current measurement techniques with failsafe measurement hardware, we can provide industrial units programmed to interface with your production line via the PLC that are pre-programmed to take measurements at the appropriate time and flag up out of limit measurements.

Special connectors may also be used to protect the terminals of the device during handling.

Automating tests

In most scenarios where regular sub-assembly testing is required, it is likely that this should be automated.

Programmable Logic Controllers (PLC) interfaces are the most common way this is achieved, either via digital I/O or serial communications.

Each test should take up as little of the Takt, or cycle time, as possible, however sufficient time must be allocated to take good and accurate measurements.

The PLC interface is normally used to indicate a pass or failure state, whereby audible or visual indication is used to notify the operator to check the connectors, wiring or other reasons for failure.

Logging results

While not strictly necessary, it can be useful to create a log of test measurements for the purpose of improving reliability through statistical process control. Sending this data serially or storing it locally are both viable solutions for this.