What is the minimum inspection set for a Transit Case?

Answer: Incoming, first article and pre-shipment. Dimensions and seal get one round each; drop only at first article.

How does a first article differ from a pilot build?

Answer: The first article proves the tool; the pilot build proves assembly, latch force and label position.

Is vacuum testing mandatory?

Answer: It is the fastest method, thirty seconds with a located leak. Water spray is the fallback.

Can drop samples go back into service?

Answer: No. A shell that looks intact may be crazed inside, so it stays as training stock.

How far should batch traceability go?

Answer: Mould number, year-month and shift, laser-marked on the base away from load paths.

Transit Case Acceptance Standards: Test Items and Verdicts

Quick answer: A Transit Case is not accepted by opening the lid at goods-in. Five gates cover incoming material, first article, dimensions, seal and dust, stacking and drop, each with its own sample size and pass threshold.

The Five Inspection Gates for a Transit Case
Incoming Material and First-Article Checks
Dimensions and Wall Thickness Sampling
Seal and Dust Testing: Vacuum, Spray, Powder
Stacking and Drop: Load, Cycles, Verdicts
FAQ

1. The Five Inspection Gates for a Transit Case

A Transit Case is accepted at five gates, not at the loading dock. Resin lot changes show up as colour and melt index drift, mould wear as lid offset, and low torque on the third drop.

Gate	Timing	Sample	Criteria
Incoming	each lot	3 bags	MFI 8±1.5, 48 h spray
First article	first shot	3 units	dimensions, wall points, vacuum
In-process	every 2 h	1 per cavity	flash, lid offset, latch force
Pre-shipment	before packing	level II	AQL 2.5, fatal zero
Goods-in	after unloading	2 per pallet	marking, reports, stack state

In-process is the gate most often dropped. Lid offset usually passes the first article and fails by shot 3,000, so sample by band: 8 units under 500, 20 above 2,000. Each gate needs a named signatory.

2. Incoming Material and First-Article Checks

Incoming covers resin, gasket and hardware. Recyclate above 20% costs falling-dart impact, gaskets are taken at Shore A 55±5, and latches must pass 48 hours of salt spray without white rust.

Transit Case: white case open on a warehouse bench, tool-cut foam in the base, grey tray and tools beside, pallets and forklift behind

The first article is the largest single check: three units, full dimensions, eight wall points, one vacuum run, one sectioned to read weld-line position and stress whitening. Record measured values rather than the word pass.

Two failures stop the tool for review; that clause belongs in the contract annex.

3. Dimensions and Wall Thickness Sampling

Outside dimensions take a caliper, internal ones a tape and square, since radiused corners leave jaws unseated.

Item	Gauge	Tolerance	Frequency
Outside L/W/H	caliper	±2.0 mm	5 per lot
Internal	tape, square	±1.5 mm	5 per lot
Wall	ultrasonic	3.2±0.25 mm	8 points per unit
Lid offset	feeler	≤0.8 mm	every unit
Base flatness	plate, feeler	≤1.0 mm	3 per lot

Wall thickness needs ultrasound, eight points a unit: at 3.2 mm nominal the spread runs 2.95 to 3.45 mm, and anything under 2.9 mm cracks first on a drop. Flatness beyond 1.0 mm rocks the fourth layer; a handle boss under 4.5 mm whitens under load.

4. Seal and Dust Testing: Vacuum, Spray, Powder

Sealing is graded airtight, watertight, dust-tight. Air tightness pulls to −30 kPa for 60 seconds and accepts a 0.5 kPa decay; leaks sit at the gasket joint and hinge boss.

Transit Case: white case open on a machine-shop bench, black lid gasket visible, tools in the base foam, grey hopper behind

Water follows IPX5 at 6.3 mm and 12.5 litres per minute for three minutes, paper inside staying dry. Dust follows IP6X: 2 kg of talc, eight hours of cycling, −20 kPa inside, no powder on the cavity afterwards.

Dust rigs are costly, so volume lots run vacuum only: a Transit Case that holds vacuum keeps talc out. Gasket compression stays at 30% to 40%, and closing gap within 0.3 mm.

5. Stacking and Drop: Load, Cycles, Verdicts

Both tests destroy the sample, so both run at first-article stage: 1.6 times rated load over four layers for 24 hours, then 2.0 mm of allowed mid-wall deflection.

Test	Condition	Verdict
Static stack	4 layers, 1.6× load, 24 h	≤2.0 mm, no crack
Vibration	3–100 Hz, 30 min	latch closed, screws tight
Free drop	1.2 m, 5 faces 1 edge	no crack, latch works
Latch fatigue	500 cycles	force drop ≤20%
Handle load	2× load, 10 min	no permanent set

Drop order is corner, edge, face: a corner concentrates energy, so a crack there means a radius too small. 1.2 m covers manual carry.

Verdicts are graded, never phrased as pass. Seal failure, latch release and shell cracking are fatal and reject the lot; offset beyond 0.8 mm is major at AQL 1.0.

Conclusion

A standard is worth what its gauges, numbers and signatures are worth. Incoming checks the blend, the first article the measured values, sealing the decay, stacking and drop the deflection.

Trace batches to mould and shift and acceptance stops being a one-off act; that is what makes a Transit Case standard enforceable.

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.