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Anyone who's worked in SMT knows the scene: every month during inventory, the system says the stock is there, but the line has nothing to use.
Not stolen. It's just that those materials became unusable long ago.
I chatted with a workshop manager who'd been in SMT for over a decade. He ran me the numbers: last year during cleanup, they found three boxes of materials purchased in 2019 — labels intact, packaging unopened, book value over two hundred thousand RMB. But when they checked the batch numbers — the shelf life had expired long ago. The moisture-sensitive components had absorbed moisture. The whole batch was scrapped.
"We ordered a little extra, thinking we'd use it later. Three years went by, and two hundred thousand just vanished." The look in his eyes said it all.
This isn't an isolated case.
In electronics manufacturing, where margins are razor-thin, 5–8 percentage points off net profit is the difference between profit and loss. Dead stock is the quietest profit killer in an SMT factory. It doesn't blow up like a wrong-material incident — it eats away at your cash flow, little by little, year by year.
R&D changes a part number, but procurement keeps ordering from the old BOM. By the time anyone notices, hundreds of reels of the old material are sitting in the warehouse. Can't use them, can't return them, can't sell them — they just gather dust on the shelves.
After a double-sided board line upgrades to HDI, the old through-hole components become completely useless. Materials sourced specifically for the old process turn from "inventory" into "scrap" overnight.
Consumables like solder paste and red glue set aside during SMT changeovers are scrapped once they pass their expiration date. And moisture-sensitive components have strict storage requirements — leave them too long in poor conditions, and the whole reel is ruined.
A reel gets partially used, and the leftover is tossed back onto a shelf. Next time someone needs that same part, they can't find it after searching forever, so they just order a new one. That leftover reel sits in the corner longer and longer, eventually becoming dead stock.
Worse still, dead stock is like "silent assets" — still on the books, but practically unusable. No one clears it, no one writes it off. It just sits in the warehouse year after year.
In theory, every factory knows the FIFO principle. But in practice — materials get tossed into any open spot during receiving; pickers grab whatever's easiest to reach; and during rush orders, nobody has the patience to dig through old batches.
The result: old batches get buried under new ones, pushed deeper and deeper until they expire and get scrapped. Those "forgotten" materials are still on the books but have long since become unusable.
The system creates an electronic file for every reel. On receiving, batch number, quantity, production date, and expiration date are automatically recorded. On dispatch, the system automatically matches the oldest batch. The operator has no choice — the system assigns exactly which reel to take. Try to grab a different one? The equipment blocks it. FIFO is no longer a matter of discipline — it's baked into the system's core logic.
The system automatically monitors the expiration date of every reel. Warnings are sent automatically as materials approach expiry. Managers can see at a glance which materials are about to expire and prioritize them for use. No more "we found out after it expired" — now it's "we knew before it was too late."
Every reel is tracked by the system from the moment it enters — which slot it's in, how much is left, when it was received. The next time someone needs the same part number, the system proactively recommends the leftover reel first. Leftovers are no longer "forgotten" in the corner — they're "awakened" by the system.
The system automatically tracks dwell time and turnover frequency for every reel, generating a dead stock report. Managers can see instantly which materials haven't been used in a long time and decide: reallocate, return, or scrap. Dead stock no longer needs to be "discovered" by someone — the system tells you proactively.
Materials management in SMT factories is undergoing a profound shift — from "people managing materials" to "systems managing materials."
And this shift often starts not with grand, earth-shattering projects,
but with a single reel of material that was forgotten in the corner for three years.
CN 
