Quick question: how are you quantifying serviceability during early design reviews? We shaved 22% off assembly time by consolidating fasteners, but our pilot techs needed 2x longer to swap a subassembly in the field; adding a tool-less latch would cost $1.14 per unit and add about 8 seconds to build — does that trade pencil out for you?
I’d run a quick break-even and bake a maintainability KPI into the spec. $1.14 + “adds about 8s” vs minutes saved per swap × (field labor + downtime): if the latch saves about 4 min and your blended cost is $2/min, you break even at about 0.14 swaps/unit and you also hit a <5 min gloved swap target. @OP what’s the measured minutes saved with the latch and what do you use for downtime $/min?
This drives me nuts: I set a target like “P90 swap ≤5 min with gloves and a headlamp,” then run a cold/dust validation; with swaps taking 2x longer, the $1.14 latch is usually a win and the +8 s on build is noise. If failures are truly rare, keep screws and stock a latch retrofit; what’s your swap rate per unit-year?
— @OP I’d gate it with a simple maintainability trial: two first‑time techs on a cold truck bed, timer rolling; if median swap >5 min, spend the $1.14 and eat the about 8 s build hit. If seal or tamper is a worry, a glove‑friendly captive quarter‑turn is a decent middle ground. How many swaps per unit‑year are you seeing?
I’d put a dollar value on each minute of field time and do a quick break‑even: if the latch cuts MTTR by about 3 minutes and you expect even one swap per unit‑year, the labor + downtime likely dwarf the extra BOM and a few seconds in build. @OP what’s the expected swap frequency for that subassembly and your loaded field minute rate? If glove use makes it “2x longer,” the latch probably pays for itself on the first cold‑night call.
@amartin’s trial is solid; I’d set a ‘gloves-on, cold, low light’ P90 swap target (say under 4 min) and greenlight the latch if it clears it. Small caveat: validate the latch with 1,000 actuations plus salt-fog/thermal cycling so you don’t trade speed for a new failure mode. How many swaps does a typical install see in a year, and are most of them in bad weather?
I’d bake service into the BOM, @OP: add an “MTTR penalty” line = expected swaps × minutes × burdened field rate × after‑hours factor, and stack that against $1.14 + the “about 8 seconds” at line rate. If year‑one clears break‑even, take the latch and qualify it with a gloves/grit 5k‑cycle test so you don’t buy a new failure mode. What’s your loaded field minute cost?