I recently attended an Automotive conference where the presenter talked about Straight Through Ratios (STR). What he meant was a vehicle that went through the full assembly process without a single fault being detected.He showed a live screen with today’s statistics, presented on a huge Andon Board (LCD screen) along the assembly line. Only 32% of the vehicles went straight through without a fault. He described the cost of both detecting and correcting defects on the 68% of vehicles coming down the line with problems. A massive cost.
I cannot recall such a statistic being used in Aerospace. Imagine if we were to calculate the straight through ratio on a civil aircraft including all sub-assemblies. I guess we would have a 0% STR? It would therefore not make much sense to measure, however what we can measure is the Right First Time (RFT) ratio for a component or sub-assembly by operation or series of operations. By focussing on a tighter measure we can focus design engineers and manufacturing engineers attention and give them a real measure of their performance.
Essentially there are three ways to implement:
- We can tackle at the design and pre-production phase
- We can tackle when the component or sub-assembly is in production
- Or both of the above
This is what ATS was asked to do at a major Aerospace OEM. For the design and pre-production phase we used dimensional and tolerance data from the CAD/CAM system and compared with the physical pre-production parts. The resulting differences enabled us to help the OEM to refine the design and manufacturing process to achieve close to 100% RFT levels during production runs.
For the production process we implemented a combination of attribute (visual) and variable data collection systems at the inspection steps to continually improve the process.
Our experience and the improvement in RFT has led to a new data driven program being introduced by the OEM for their suppliers so they can improve their RFT ratios.
In Aerospace we cannot offer a one size fits all solution but if you would be interested in sharing experiences with us just let me know and we can discuss initially on a conference call.