How many people should attend a Case Showroom acceptance?

Answer: Three: one measures, one records, one signs for the buyer. The factory adds a quality engineer and a mould technician.

Are 46 samples enough for a whole batch?

Answer: Enough for process stability, not lot consistency. Cavity differences show at two units per model; the bulk lot needs a second round at ten percent.

What if the salt spray fails?

Answer: Check hardware grade and plating thickness first, then chamber salt concentration and temperature drift. One is a supplier issue, the other equipment.

Where must a limit be written to count?

Answer: On the acceptance sheet, signed by both sides, with the drawing tolerance attached. A limit living only in email dies with the people.

Does rework repeat all nine checks?

Answer: No. The failed item repeats, neighbours sharing the mould get extra sampling, the rest stand on the original record.

How long should a Case Showroom record be kept?

Answer: Two years minimum, one reorder cycle; export projects run three to five.

Case Showroom Acceptance: 46 Samples, Nine Checks, Two Reworks

Quick answer: A Case Showroom acceptance repeats only when the criteria sheet is signed before anything opens, sampling is calculated, and each failure is graded. Forty-six samples, nine checks, two reworks.

The First Sheet Comes Before the First Case
Measuring 46 Samples by Hand
Latches, Lids and Three Numbers
96 Hours of Salt Spray and Thermal Cycling
Grading a Failure and Closing the Loop
Records That Survive the Next Year
FAQ

1. The First Sheet Comes Before the First Case

Forty-six samples stood in two rows in the Case Showroom, each numbered in pencil. The factory wanted to open cases first and agree on limits after; the buyer refused.

Check	Sampling	Limit	Source
Colour	All 46	ΔE up to 1.5, no through-scratch	Chip + spectrophotometer
Dimensions	All 46	Nominal ±0.8 mm	Drawing + caliper
Lid seam	All 46	0.25 mm feeler blocked, step under 0.4 mm	Feeler + depth gauge
Wall	2 per model	3.2 mm ±0.15 mm	Ultrasonic gauge
Latch force	1 per model	180 N without release	500 N gauge
Hinge life	3 units	5,000 cycles, gap under 0.2 mm	Cycling rig
Sealing	3 units	30 minutes at 1 m, paper dry	Tank + paper

No limit says "feels fine". Twenty-three models at two units puts appearance and dimensions on everything; destructive checks take seventeen pieces.

2. Measuring 46 Samples by Hand

Measurement runs large to small: length, width, height, then cavity, rim and base wall. Six points per case are marked on the floor, so another operator lands in the same spot next morning.

Case Showroom: an orange-red plastic case standing upright, one curved handle spanning the top, two short ribs at each corner and two feet underneath

Six points across forty-six cases is 276 numbers, called twice. One 1,180 mm case failed at 1,181.1 mm while another cavity of the same mould read 1,180.2 mm, so the shrinkage spread had been stretched by the long dimension.

Seams take feeler stock. A 0.25 mm blade runs the joint, and wherever it enters, the case is marked down.

3. Latches, Lids and Three Numbers

Holding force comes from a 500 N gauge at the latch root, pulled at 50 mm per minute, three pulls with the median kept. This batch read 205, 198, 212 and 196 N against a 180 N line. Median, not mean, so one slipped hook does not drag the result.

Lid loading runs at 80 kg for 24 hours, deflection read at once, 2 mm or less passing.

Hinge life runs at 20 cycles a minute, so 5,000 cycles takes four hours ten minutes; these units grew 0.08 to 0.14 mm at the root.

4. 96 Hours of Salt Spray and Thermal Cycling

Salt spray applies to hardware only. Latches, hinge pins and lock cores go in three sets each for 96 hours, then get rinsed, dried and held against a rust chart. Past 5 percent, the first question is material grade, not the plater.

Case Showroom: the same orange-red case at a three-quarter angle on a bench, handle to the left, two small tabs on the upper right edge

Thermal cycling holds −25 °C and 60 °C for four hours each, three rounds, with two hours at room temperature before anything opens. Cold breaks latches; heat shows as sagging beside the handle.

Drops run from 1.2 m onto corner, edge and face, and skipping them moves the acceptance to a loading dock.

Sealing is tested on the whole case: four sheets of paper inside, lid latched, thirty minutes at 1 m. Wipe the shell first, or condensation reads as leakage.

5. Grading a Failure and Closing the Loop

Nine checks produced two problems: three cases with a 0.45 mm lid step, twelve with ΔE at 1.9. The first went to mould repair, the second was re-shot with corrected masterbatch.

Grade	Typical item	Action	Re-check	Signs off
1 Critical	Leakage, crack, latch release	Stop batch, re-inspect all	Same rig, extra cavities	Both quality leads
2 Major	Dimension, colour, hinge gap	Rework and re-sample, or written concession	Same gauge, same points	Buyer's project lead
3 Minor	Light scuff, label off 1 mm	Log only, rework after three	Visual	Inspector

Concessions belong on paper. No Case Showroom batch leaves on a verbal nod.

Re-checks use the same gauges and people within 48 hours; a pass from fresh hands with a fresh caliper proves nothing.

6. Records That Survive the Next Year

A Case Showroom record worth keeping comes from these moves, not the last signature:

One disposable number per sample, as day code, model and sequence, such as 926-A17-03
Three photos per check: reading, feature, whole case
Reworked units boxed apart, labelled with item and date
One signed sheet per side, each failure carrying its real number
Files in three levels — model, batch, item — dated in the name

Conclusion

An acceptance is worth the readings it can reproduce six months later. Forty-six samples, nine limits and two reworks in a Case Showroom compress into two signed sheets and a set of photographs. Fix the limits, zero the gauges, grade the failures. Then the next Case Showroom visit starts from a signed sheet.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.