Should cartridge safety case acceptance standards go into the contract?

Answer: Yes, as an annex carrying the items, sampling plan and limits. A clause naming a standard with nothing attached gives no testable term.

Air decay or immersion?

Answer: Air decay. At 30 kPa for 60 seconds it returns a verdict and damages nothing, so it can run on every unit.

One critical defect appeared. Can we double the sample and retest?

Answer: No. The acceptance number for a critical defect is zero, so one finding rejects the lot.

The cavity is 0.3 mm out. Is that a failure?

Answer: Check the direction. Length and width allow 0.5 mm, so it sits inside; if four sides drift one way and push the lid gap past 0.8 mm, it is major.

How long should records be kept?

Answer: Three years, covering warranty and traceability and long enough for a cavity trend to appear.

Cartridge Safety Case Acceptance: Items and Verdicts

Quick answer: Acceptance of a cartridge safety case rests on three groups of evidence: appearance and marking, size and fit, and function. Give each item a method, a sampling point and a limit, then attach a defect class and sampling plan.

Where Cartridge Safety Case Inspection Starts
Matching the Sampling Plan to the Lot
Size and Fit Lines for Each Dimension
Function Tests for Seal, Latch and Hinge
Verdict Rules and Record Keeping
FAQ

1. Where Cartridge Safety Case Inspection Starts

Inspection drifts into argument when drawings stay silent. Split a cartridge safety case into three groups: appearance, size and fit, and function. Appearance covers scratches, sinks, flash and labels; size covers cavity, envelope and lid gap; function covers air decay, latch force and hinge life.

A scratch is easiest to miss before the insert goes in, so appearance comes first; the seal needs an assembled unit, so function comes last. Done that way, a cartridge safety case reaches a verdict in six minutes.

Group	Item	Method	Pass limit
Appearance	Scratch, sink, flash	Visual, 800 lux at 500 mm	None on the face; 10 mm elsewhere
Size	Cavity, depth	Caliper, 0.02 mm	0.5 mm; depth 0.4 mm
Size	Lid gap	Feeler gauge	0.8 mm or less
Function	Air decay	Decay tester	30 kPa, 60 s, 1 kPa drop
Function	Latch force	Push-pull gauge	180 N, plus or minus 20 N
Function	Salt spray	Neutral, 48 h	No red rust

Keep first-article approval apart from lot inspection; merging the two leaves the batch unwatched.

2. Matching the Sampling Plan to the Lot

Under GB/T 2828.1 at general level II, a lot of 501 to 1200 units maps to code letter J and a sample of 80. Sheets often say five units, yet five cannot support a verdict.

A cartridge safety case needs three defect classes: critical, the ones defeating seal or latch, at an AQL of 0.25; major at 1.0; minor at 2.5.

Class	Typical items	AQL	Ac and Re at n = 80
Critical	Air decay, broken latch	0.25	0 and 1
Major	Cavity, latch force, rust	1.0	2 and 3
Minor	Face scratch, colour shift	2.5	5 and 6

Two rejected lots in five send the next to tightened inspection with double the sample; ten clean lots restore normal.

3. Size and Fit Lines for Each Dimension

State the datum before the tolerance. Measure cavity length and width 10 mm above the floor, depth from that floor to the inside of the lid, and the envelope at the widest mid-body point.

Cavity length and width take plus or minus 0.5 mm, depth 0.4 mm, since depth decides whether the lid presses on the load. A cartridge safety case envelope takes 0.8 mm of room for stacking pitch, and empty weight is held to 3 percent: heavy means walls drifted, light means short shots.

Check flatness on a granite plate with a feeler gauge: four corners down but 0.6 mm at the middle fails. Read the lid gap at eight points; a spread above 0.4 mm means a twisted body, not a uniform shift.

4. Function Tests for Seal, Latch and Hinge

Air decay beats immersion as the routine test. Charge to 30 kPa, hold 60 seconds, accept a drop of 1 kPa or less. Air is non-destructive, so every unit can run it; immersion puts water inside and needs drying.

Read latch force on all four catches: 180 N, plus or minus 20 N. A spread above 15 N fails the unit, because hook and keeper have drifted and one corner will not close.

Hinge life runs 5000 cycles at 12 per minute, gap logged each 1000, growth held to 0.3 mm. Metal parts take 48 hours of neutral salt spray: red rust fails, white rust is recorded only. Function samples stay separate from drop samples; micro-cracks spoil the reading.

5. Verdict Rules and Record Keeping

On a cartridge safety case, critical defects sit outside the AQL arithmetic: one rejects the lot. Major defects follow the acceptance and rejection numbers. Minor defects may pass by written concession, up to three lots a year per supplier.

Re-inspection covers the failed item only: double the sample, retest that item, and the lot passes if it clears. The cavity number is moulded into the floor, 8 mm high, and lot, cavity, inspector, date and readings are kept three years.

Conclusion

A standard works when a third party repeats each item: method, instrument, sampling point, limit. Bind defect classes to the sampling plan and the verdict stops depending on mood. Settle those three groups first, and the cartridge safety case is under control.

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.