How many items should a drone case acceptance sheet carry?

Answer: Eighteen to twenty-two, grouped into appearance, dimension, seal, drop, latch and ageing, each with a numeric line and a named recorder.

Can immersion replace pressure decay?

Answer: It can, but it is slow: 30 minutes against 60 seconds. The line uses decay, the lot immersion.

Why is the drop height 1.2 m?

Answer: It covers a one-hand carry dropped at hip level and a slide from a stack. The load must match the real all-up weight, or corner cracks pass.

Is ΔE 1.5 a hard line?

Answer: On the A surface, yes. The B surface and cavity relax to 2.5, provided both sides use one instrument.

What if sampling finds one critical defect?

Answer: Ac is zero, so one unit fails the lot. No extra sample is drawn; the lot is sorted or rejected.

Drone Case Acceptance Standards: Test Items and Pass Criteria

Quick answer: A drone case is accepted item by item, not by first impression. Dimensions, seal, drop, latch life and ageing each carry a written pass line, sampling follows the lot size, and defects are judged as a lot.

How the Drone Case Inspection Splits into Three Layers
Where the Appearance and Dimension Lines Sit
How Seal and Drop Tests Are Judged
Latch Life and Thermal Ageing Rulings
Sampling Plans and How a Failed Lot Is Handled
FAQ

1. How the Drone Case Inspection Splits into Three Layers

Acceptance sheets fail when every check shares one page and the inspector passes parts by feel. A drone case is judged at three levels, each with its own pass line and signature.

Incoming covers the PP melt flow index, the masterbatch lot and the hardware. A shift beyond ±0.3 g/10min returns the lot, since the same settings then mould a different wall. Valve diaphragms must crack between 0.015 and 0.025 MPa.

Level	Items	Release condition
Incoming	melt index, masterbatch, valve pressure	all three pass
First article	12 dimensions, colour, unit weight	all inside tolerance
Patrol	appearance, lid gap, latch force	three clean groups
Outgoing	80-unit sample, 3 seal retests	defects at or below Ac

First article cannot be skipped. Every mould change, colour change or stop over four hours needs a fresh one, and a unit weight drift beyond ±2.5% means the wall has already moved.

2. Where the Appearance and Dimension Lines Sit

Appearance starts arguments at goods-in, so every item needs a number. Colour is judged on ΔE against the signed sample at 1.5 or less; sink marks stay under 0.3 mm on the A surface and 0.6 mm on the B, flash under 0.2 mm, scratches under 5 mm with two per face.

Drone Case: red case open with dark foam holding a folded-arm drone, a screen controller, a battery and a gimbal, lid foam in place

Dimensions split into envelope and fit. The 520×390×215 mm outer size carries ±2.0 mm and the 470×340×180 mm cavity ±1.5 mm. Lid gap stays at or under 1.5 mm across eight feeler-gauge points, spread 0.6 mm. Floor flatness is 1.0 mm, and foam leaves 1.0–1.5 mm per side.

Hinge coaxiality and latch-seat symmetry are usually missing: beyond 0.6 mm the lid sits high on one side, gasket compression varies by 10%, and water enters at the low corner.

3. How Seal and Drop Tests Are Judged

Sealing a drone case is settled by immersion and pressure decay. The closed case sits under 1 m of water for 30 minutes; after drying, the cavity must show no water and the indicator paper no colour change. Pressure decay charges to 20 kPa and accepts a drop of 1.0 kPa or less in 60 seconds.

Test	Condition	Pass ruling
Immersion	1 m, 30 min	dry cavity, unchanged paper
Pressure decay	20 kPa, 60 s	1.0 kPa drop or less
Drop	1.2 m, 10 drops	no through-crack, latches shut
Vibration	3–100 Hz, 30 min	pins travel under 1 mm

Drop testing follows one corner, three edges and six faces, ten drops from 1.2 m at the real all-up weight. No through-crack, no latch release, no lid shift beyond 3 mm. The seal is retested afterwards, since cracks open at the corner rib roots.

4. Latch Life and Thermal Ageing Rulings

Latch judgement on a drone case has two stages. Outgoing force is 55 N ± 8 N, averaged over three pulls at the tongue centre; after 2,000 open-close cycles it must still reach 35 N.

Thermal cycling runs -20 °C for 4 hours and 55 °C for 4 hours, three cycles, unopened. Pressure decay is measured at once, permanent gasket set may not exceed 1.2 mm, and 72-hour salt spray must rate 9 or better.

5. Sampling Plans and How a Failed Lot Is Handled

Sampling follows GB/T 2828.1, normal inspection, single sampling, level II. A lot of 501–1200 units maps to code J, sample 80; 1201–3200 to K, sample 125.

Class	Typical items	AQL	Ac/Re at n=80
Critical	seal failure, latch release	0	0 / 1
Major	dimension, cracks	0.65	1 / 2
Minor	colour, scratches	1.5	3 / 4

A failed lot is never sorted and shipped quietly: every unit is inspected and the lot resampled, or the lot is rejected. A concession needs written confirmation of the defect and quantity plus two retained samples kept 24 months.

Conclusion

An acceptance standard earns its keep when every line becomes an action: who measures, with what, where the reading lands, and the consequence. Fix the list once and a drone case is accepted on data, not on feel.

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.