Customers (Automotive OEM and tier two suppliers) were having intermittent fuel rail leakage. Rails were 100% tested and all passed standard leak test inspection. However, one per 100,000 rails would leak once in the field, causing the potential for injury.
Why was this problem intermittent? Using 50% of the manufacturing tolerances, very defined disciplines and 100% leak test inspection, parts would still fail in the field. Promess was contacted as a last resort. Customers actually purchased our lab for a day to use our Electro-Mechanical Assembly Press (EMAP) for differential monitoring to see if we could detect the problem during the assembly process.
Promess assisted in a 200-part run for 12 hours. Upon completion, we could detect 100% of failed components (reason for failure is confidential) using differential monitoring techniques in the assembly process, even though they passed the pressure test (see graph above).