3 ms·

True, the design is one important part, but the design can be 100% on, but the manufacturing and the operational inspections are important to present failures t

True, the design is one important part, but the design can be 100% on, but the manufacturing and the operational inspections are important to present failures too. Variance from controlled manufacturing conditions can result in parts that basically look and perform ok at first, but are at risk of failing early, that's why aircraft have inspection schedules - that are sometimes increased due to increased cycles on some routes/airports. (and of course there is the case of the part being damaged somehow, where some of the other comments have linked cases where this happened catasropically).

beerandt 7y ago
Hmmm... I'm not real familiar with that mass production qaqc. Is there a term that describes a minimum design spec (or similar aspect), that takes into account the actual manufacturing (and other) variances? I'm thinking that in construction, a rough equivalent would be a designs constructability / bidability review.
- bumby 7y ago
  I'm not sure what you're asking but there is term in manufacturing called DFM or design for manufacturability. Otherwise, design drawings are loaded with specs that call out design tolerances etc. QA and process control are used ensure these tolerances are met
- digikata 7y ago
  The design may call out a specific material and how to manufacture it, say make this part out of 6061 Aluminum, and. mill it in this way. You can look up the standard properties of that material. But depending on how that material is worked, cut, bent etc, you would expect in come cases some changes in the material properties or just sensitivities to fatigue. E.g. if you cut a sharp corner into that metal, fatigue will increase in that corner over the life of the part, so maybe you specify rounded corner - but how much it makes a difference you won't do necessarily a whole specific detailed study on it unless its a critical part or corner. If it's milled, if the machine that day has a duller bit, maybe it heats up the part more, and the material properties shift a bit more due to the heating. All these and are controlled in the process, but are still little things lead to variation, and maybe the controls fail one day and some slightly different aluminum makes in into the process. For critical parts on the aircraft, there is the backup of inspecting for aspects like accelerated fatigue just for variation of manufacturing, of environmental contributors, etc. It's a lot like security defense in depth - many layers of protection for lives (and aircraft industry trustability linked to profitability too) at stake.

beerandt 7y ago

Hmmm... I'm not real familiar with that mass production qaqc. Is there a term that describes a minimum design spec (or similar aspect), that takes into account the actual manufacturing (and other) variances? I'm thinking that in construction, a rough equivalent would be a designs constructability / bidability review.

bumby 7y ago
I'm not sure what you're asking but there is term in manufacturing called DFM or design for manufacturability. Otherwise, design drawings are loaded with specs that call out design tolerances etc. QA and process control are used ensure these tolerances are met
digikata 7y ago
The design may call out a specific material and how to manufacture it, say make this part out of 6061 Aluminum, and. mill it in this way. You can look up the standard properties of that material. But depending on how that material is worked, cut, bent etc, you would expect in come cases some changes in the material properties or just sensitivities to fatigue. E.g. if you cut a sharp corner into that metal, fatigue will increase in that corner over the life of the part, so maybe you specify rounded corner - but how much it makes a difference you won't do necessarily a whole specific detailed study on it unless its a critical part or corner. If it's milled, if the machine that day has a duller bit, maybe it heats up the part more, and the material properties shift a bit more due to the heating. All these and are controlled in the process, but are still little things lead to variation, and maybe the controls fail one day and some slightly different aluminum makes in into the process. For critical parts on the aircraft, there is the backup of inspecting for aspects like accelerated fatigue just for variation of manufacturing, of environmental contributors, etc. It's a lot like security defense in depth - many layers of protection for lives (and aircraft industry trustability linked to profitability too) at stake.