How many hand carry hard case samples are enough?

Answer: Four up to 300 pieces, six from 301 to 800, ten above 801, drawn across pallets and cavities.

Why test the handle at 60 kg?

Answer: A 22 kg case peaks near 2.7 times its static weight while walking, landing around 60 kg.

Is -25 °C enough for the cold drop?

Answer: Northern road transport, yes. High-latitude exports need a -30 °C round.

Should the latch be as tight as possible?

Answer: No. Above 110 N crews pry with tools, and the distorted hook leaks first.

Does every cosmetic defect reject the lot?

Answer: No. White marks at the boss reject at one piece; scuffs are reworked.

Hand Carry Hard Case Acceptance at -25 °C: 1.2 m Drops

Quick answer: A hand carry hard case is accepted in four groups: first article and appearance, dimensions and handle fit, hinge and latch life, then cold drop and stacking. Load 22 kg, condition at -25 °C for four hours, drop 1.2 m on six faces; one through-crack sends the lot back.

Four Inspection Groups and Reject Levels
First Article and Appearance: Colour, Parting Line, Rim Flatness
Handle Static Load: 60 kg for 60 Seconds
Hinge and Latch Cycles, Opening Force
Cold Drop, Stacking and Conditioning
FAQ

1. Four Inspection Groups and Reject Levels

Arguments on an inspection floor are rarely about strictness; they are about whose number counts. A hand carry hard case needs one sheet fixing the groups, the sample size and the signature, and the order never varies: no signature, no start.

Defects run in three levels. A through-crack, a broken latch hook or a wall below 3.2 mm is critical: one piece rejects the lot. Colour drift or a rim out of flat is major: tighten sampling and retest. Scuffs are minor: sort and rework.

Group	Main items	Equipment	Level
Appearance	Sealed sample, colour, parting line, rim	Spectrophotometer, feeler, plate	Major
Dimensions	Internal size, wall, handle holes, torque	Calipers, gauge, torque wrench	Critical
Hinge and latch	Cycles, opening force, pin clearance	Cycle rig, push-pull gauge	Major
Drop and stack	Conditioning, six faces, deflection	Chamber, drop rig, load blocks	Critical

Sampling follows batch size, drawn across pallets and cavities.

2. First Article and Appearance: Colour, Parting Line, Rim Flatness

A first article is not the best-looking case in the run. Take one from every cavity over three consecutive shots and measure internal size, wall thickness and handle holes.

Hand Carry Hard Case: a navy blue case on a roller conveyor, vertical ribs facing the camera, folding handle flat, two latches on the edge

Colour on a hand carry hard case is read at three points: lid face, body side, handle. Keep ΔE within 1.0 of the sealed sample. A fingernail that catches a parting-line ridge above 0.2 mm marks a major defect.

Rim flatness decides sealing. Turn the case on a plate and run a 0.05 mm feeler around the rim: no gap above 0.6 mm.

3. Handle Static Load: 60 kg for 60 Seconds

The handle is the only part of a hand carry hard case under repeated dynamic load. Static load is 2.7 times working weight: 60 kg on a 22 kg case, held 60 seconds, measured after ten minutes. Residual deflection under 0.8 mm passes.

An M5 bolt into a 34 mm boss takes 2.5 N·m. Too little and the handle works loose; too much and the boss creeps.

Six checks settle a handle assembly:

60 kg for 60 seconds, no crack
residual deflection under 0.8 mm
boss at least 34 mm, radius R2.5
torque 2.5 N·m, witness mark aligned
sag under 1.2 mm on a 140 mm span
folded handle within 0.5 mm of the lid

4. Hinge and Latch Cycles, Opening Force

On a hand carry hard case, hinge acceptance is about looseness rather than breakage. After 8000 cycles the lid sags no more than 3 mm and pin clearance stays under 0.3 mm, which is two and a half years at eight openings a day.

Latches run 5000 cycles, with opening force logged every 500. Between 60 N and 110 N is normal. Below 60 N the hook releases itself in transit; above 110 N crews pry with a screwdriver and distort it.

Salt spray applies to metal only: 96 hours, no red rust, nickel at 8 µm or above.

Item	Condition	Pass line	On failure
Hinge	8000 cycles at 20 per minute	Sag under 3 mm	Double the sample
Latch	5000 cycles	60 to 110 N	Retest a new lot
Pin clearance	Plug gauge	Under 0.3 mm	Reject the piece
Salt spray	96 hours	No red rust	Return the lot

5. Cold Drop, Stacking and Conditioning

Drop at the worst temperature. Load a hand carry hard case with 22 kg, condition it at -25 °C for four hours, then finish the first drop within 30 seconds. Use a fresh sample for each face.

Hand Carry Hard Case: a charcoal case in a tray on a conveyor, combination lock with a red indicator and one latch on the side

Six faces plus one bottom edge, 1.2 m onto 50 mm steel. No through-crack, no latch release, lid offset under 2 mm.

An empty case weighs 3.4 kg. Stack five high with 180 kg for 24 hours and the side wall bulges under 3 mm. Repeat at 55 °C, where polypropylene loses 30% of its modulus.

Conclusion

Acceptance of a hand carry hard case comes down to four numbers: first-article dimensions, 60 kg on the handle, 5000 latch cycles, and 1.2 m at -25 °C. Put the levels and sample sizes in the contract annex, and a hand carry hard case is judged on data rather than mood.

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.