How many fields does batch traceability need?

A: Eleven covers all four lot levels. Extra fields slow entry and add no reach.

Why four hours on the backward query?

A: That is half a shift. Beyond it the suspect lot has usually left on the next truck.

Can one case be traced to its cavity?

A: Yes. A position mark covers cavities 1 to 8, and the date clock narrows it to one. Cases from one cavity share the same process drift.

Is 500 g of retained material enough?

A: Enough for one full composition and mechanical check, not three. A full re-test goes back to the supplier's sample.

Can records go after three years?

A: A contract may require longer, and then it governs. Otherwise three years applies, and destruction leaves a one-page schedule of lot ranges.

Batch Traceability for Cases

Quick answer: Batch traceability runs on two clocks: four hours from a returned case back to its resin lot, two hours from that lot forward to the buyers.

One returned case stands for twenty-four moulding lots
Four lot levels and the eleven fields they carry
Two clocks, two directions: four hours back and two hours forward
Quarantine that fits inside three days of output
Two drills a year, ninety minutes on the clock
FAQ

1. One returned case stands for twenty-four moulding lots

A case comes back from a distributor with a split hinge boss, and the quality manager has an afternoon to answer two questions: which resin lot sits inside it, and how many cases from that chain are already in the field. Neither answer is moulded into the part; both sit in the ratios between four lot levels.

Material passes three gates before it becomes a case: mixing, moulding, packing. The first two multiply the level above, sixfold then fourfold; the third packs eight moulding lots into one shipment. The chain is a tree, not a line.

A 1,200 kg resin lot arrives as 48 bags of 25 kg; at 200 kg per mixer charge it splits into 6 mixing batches; four shots per charge gives 24 moulding lots; at 180 cases each the lot yields 4,320 cases, packed as 3 shipment lots of 1,440.

That is the 1:6:24:3 chain. Miss one level and the quarantine triples.

The first document a factory needs is this ratio table, not a record form.

2. Four lot levels and the eleven fields they carry

Each level answers a different question, so eleven fields cannot be spread evenly. A resin lot proves who supplied the material and when; a mixing batch proves which bags entered the charge; a moulding lot proves machine, cavity and shift; a shipment lot proves which lots shared a truck.

Batch traceability in the tool room: blue moulds on green four-tier racks, a cavity-number board in front, a yellow helmet on a beam

Lot level	Lot size	Ratio to the level above	Record carrier
Resin lot	1,200 kg	starting point	goods-in ledger
Mixing batch	200 kg	1 to 6	mixing work order
Moulding lot	180 cases	1 to 4	machine log, date clock
Shipment lot	1,440 cases	8 into 1	shipping note

Eleven fields run in one line: resin lot, charge number, moulding lot, machine, cavity, date, shift, shipment lot, customer code, order number, quantity. The first five point back, the middle three fix time, the last three point to the buyer.

Marking happens twice: an in-mould date clock stamps day and shift into the base, and an outer label carries the moulding and shipment lots. Eight cavities read from the position mark, 1 to 8, so date and cavity pin one case to one lot.

Retention follows the mixing batch: 500 g per charge for 12 months, plus 3 colour plaques split between customer, factory and cabinet. They rebuild a broken lot number from a physical sample.

3. Two clocks, two directions: four hours back and two hours forward

Backward and forward queries need different indexes. One starts at the date and cavity mark and ends at a resin lot; the other runs the same chain in reverse. Opposite directions, separate lists.

Direction	Start	End	Time budget	Index required
Backward	date clock, cavity mark	resin lot	4 h	date-to-machine list
Forward	resin lot	shipment lots, customers	2 h	lot-to-shipment matrix
Lateral	one cavity number	every case in the lot	1 h	cavity-to-lot list
Gap	a missing field	nearest closed node	1 h	gap-recovery log

The four-hour backward budget: 15 min to read the base, 45 min on the machine log, 60 min through the mixing work orders, 30 min to land the resin lot, and 1.5 h held for review. The step that overruns is the work orders, three shifts at six charges a day.

The two-hour forward budget rests on one matrix: resin lots down the rows, shipment lots across the columns. Twenty-four rows scan in under 10 min; the rest goes on customer codes and order numbers.

4. Quarantine that fits inside three days of output

Three days of output is the most practical number in the table. A day ships 1,440 cases, so three days is 4,320, exactly what one resin lot makes; a material problem closes one lot and stops nothing else.

Batch traceability at the mixer: a stainless drum on blue legs beside stacked white resin bags, a worker in black at the hopper

The broken-chain rate is monthly: lots that failed to close back to a resin lot within four hours, over all lots shipped. The target is 0.5%. At 60 lots a month that allows zero, since 0.5% of 60 is 0.3. An unclosed lot costs far more in a claim than a hold would.

Records stay 3 years, covering 36 months of shipments. With 12 to 24 month warranties and a 12-month claim tail, month 37 is rarely opened.

5. Two drills a year, ninety minutes on the clock

Two drills a year, one each half, starting from a case with half its base date rubbed away.

Break point	What the floor sees	Recovery time	Owner
date clock not stamped	blank case base	2 h	moulding supervisor
outer label missing	gap in the shipment lot	0.5 h	packer
charge number not logged	6 batches merged into 1	3 h	compounder
shipment merge not registered	3 lots into 1	4 h	warehouse clerk

The pass mark is 90 min, not four hours. Internal targets sit tighter than the promise to customers, because a real complaint brings calls, photographs and emails that eat 2 to 3 hours.

Four roles must attend: moulding supervisor, compounder, warehouse clerk, quality. Leave one out and the chain breaks at his link. The record is one A4 page: start, end, elapsed time, failed link, fields rebuilt.

Conclusion

Batch traceability produces two clocks and one ratio table. The 1:6:24:3 chain fixes the lot levels, eleven fields fix the record, four hours back and two hours forward fix the query, three days of output fixes the quarantine. Aligned, two drills a year are a formality. Misaligned, they only rehearse the same confusion.

This article covers case-side specifications only and does not address any handling, loading or use of the contents.