In this guide 6 sections
A shortage found at the line was usually visible days earlier. The warning sits in three places. One is a kit check done by eye, one is an open PO whose date slipped, and one is stock allocated twice to two work orders. Trace back through these to find yours.
Start from the stopped line
The feeder is empty. The reel count says forty short. The line stops. The operator calls the supervisor and the planner hears about it by phone an hour after the placement machine went idle.
Skip the blame. Write the timeline backwards. When did stores kit this job? When was the PO placed? When did the part last show as available in the stock sheet?
Each step has a time. The gap between the first moment someone could have known and the moment the line told you is the cost of the missed warning. Pull the actual documents. The kit sheet, the PO confirmation email and a screenshot of the stock sheet from that morning are usually enough to rebuild the picture.
The kit check that did not catch it
Many shops check kits by looking at the bags. A bag holds a reel, the reel looks full and it passes. Nobody compares the count on the reel against the BOM quantity multiplied by the build quantity plus overage.
Cut tape and loose parts make this worse. An opened reel returned from an earlier job may hold far fewer pieces than its label says.
A proper kit check counts or weighs each reel, records the number and puts shortages on a list before the kit leaves stores. Ticks do not count.
- Count or weight recorded per line, not a tick
- Overage rule per part type, set by the planner
- Returned reels recounted before reuse
- Short lines listed on the kit before release
- Substitute parts flagged for approval
The open PO that slipped quietly
The part was ordered. The supplier then moved the date from a Tuesday to the following Monday. The email went to the buyer, who updated a personal sheet but never told the planner.
This is the second place the warning hides. Purchase promise dates and the production start date should be compared automatically, line by line, as soon as either changes.
Also look at lead time creep on parts you reorder often. If the quoted time keeps lengthening, the safety stock was set on an old number. Connectors, crystals and power inductors are frequent offenders.
- Promise date against work order start date
- Supplier confirmation recorded, not just the order
- Partial deliveries shown as partial
- Lead time per part reviewed on each reorder
- Buyer and planner looking at the same list
Allocation: one reel promised twice
Stock on hand is not stock available. If two work orders both need the same 0402 capacitor, the system or sheet should reserve quantities to each. Otherwise the first job takes the reels and the second finds an empty shelf.
Check whether your stock figures include material already kitted, quarantined for moisture, or held for a customer return. Any of these can inflate the number the planner trusts.
The fix is allocation by work order with a due date, so the second job shows short the day it is released. Reservations must also release. When a job is cancelled or a customer pushes it out, the held reels should return to the free pool the same day.
Build a short daily shortage review
Ten minutes each morning is enough. List jobs starting in the next five working days and check, for each part, available stock after allocation plus confirmed incoming on time.
Mark anything short. Give it an owner. Expedite fees and alternate approvals take time, so early action matters. A broker buy or a customer approved substitute needs days, not hours.
Pick the last line stoppage you had and trace it through these three places this week.
Shortage trace worksheet
A one page worksheet used after any line stoppage. It has a timeline strip with boxes for kit date, PO date, promise date, last good stock count and stop time. Below sit three tick blocks for the kit check, open PO and allocation, each with a question and a space for the finding. The closing row notes the date the earlier warning could have appeared and who owns the fix.
Open a blank worksheet to printQuestions owners ask
How far ahead should shortages be checked?
Check at least as far ahead as your longest lead time on common parts, and look tighter each day for jobs about to start. Cover every reel on the kit list. The aim is to leave time to expedite or approve an alternate.
Who owns a shortage, the planner or the buyer?
Agree it in writing. Usually the planner raises the need and the buyer owns the supplier action, and both see one shared list.
Is overage the same for every part?
No. Small passives lose more pieces on the machine than a large connector, so set overage by part type and review it against actual scrap.
What if the shortage is a customer supplied part?
Tell the customer the same day, with the count and the job it affects. Record the date you raised it, as it protects your delivery date. Ask for a firm arrival day, and agree whether the job waits or ships short.