How many points can a case cost down programme take out?

Answer: The five items total 16.1 yuan on a 198 yuan case, 8.1%. Repairs move from 1.9% to 2.7%, and at 20,000 units a year the net gain is 308,400 yuan.

Is 3.0 mm to 2.6 mm wall really impossible?

Answer: It saves 6.8 yuan, but three of ten samples crack a corner over 15 mm in a 1.0 m six-face drop. Storage cases rated under 0.6 m may accept it; shipping cases should not.

Does an EPE liner still pass the drop test?

Answer: After three 1.0 m drops the dent grows from 2 mm to 6 mm and compression set from 8% to 15%. Whether that passes depends on the duty; those two numbers are all the case side can give.

Will customers spot a cheaper label?

Answer: Yes. It ranks first on perception, and a 0.5 mm plate replaced by 0.2 mm PET leaves a 0.3 mm step in raking light. Fine indoors, not for export batches.

Does a downgrade need new certification?

Answer: Not for the five movable parts, which carry no load, seal or pressure function. Changing wall, latches or valve means rerunning drop and airtight tests.

Case Cost Down: Where Cost-Down Is Safe

Quick answer: Case cost down is part-level grading: 5 of 12 line items can move, saving 16.1 yuan per case or 8.1%, while repairs climb 0.8 points.

Grading the twelve line items
Five parts that can move
Three parts that cannot
Eight points saved, point eight paid
Validation before release
Perception ranking and the crossing line
FAQ

1. Grading the twelve line items

Twelve items sit on one sheet: wheels, liner, surface, packaging, label, wall, latches, valve, gasket, hinges, handle, tooling. Tick them off and five survive, three end the order, four follow volume.

A part passes only if the customer would not notice the failure and the case keeps its protection class; fail either test and it leaves the list.

Item	Grade
Wheels	Movable
Liner	Movable
Surface	Movable
Packaging	Movable
Label	Movable
Wall	Fixed
Latches	Fixed
Valve	Fixed
Gasket	Volume
Hinges	Volume
Handle	Volume
Tooling	Volume

The five add up to 16.1 yuan, 8.1% of a 198 yuan case; cutting the three fixed items too frees 11.8 yuan, but then it is another model.

2. Five parts that can move

Wheels come first. From 75 mm to 65 mm and two hub bearings to one saves 4.2 yuan. The hub reaches 48 ℃ after 5 km of towing, and the rim wears 0.4 mm after 200 stair trips.

Case cost down checks where olive and black cases sit stacked on timber pallets in a desert yard with two handlers lifting one

The liner goes from 25 mm EVA to 18 mm EPE for 6 yuan. Compression set moves from 8% to 15%, and three 1.0 m six-face drops deepen the dent from 2 mm to 6 mm. Surface is 400 grit etched to 200 grit for 2.5 yuan; gloss rises from 12 to 21 units after 200 wipes.

Packaging drops from five-ply AB to three-ply B board with folded paper corners, 3 yuan; after 72 h under a 6-high stack, carton crush grows from 1.5 mm to 4 mm. The label swaps a 0.5 mm plate for 0.2 mm PET film, 0.4 yuan, the smallest saving and the loudest argument.

Part	Original	New	Yuan
Wheels	75 mm	65 mm	4.2
Liner	25 mm EVA	18 mm EPE	6.0
Surface	400 grit	200 grit	2.5
Packaging	Five-ply	Three-ply	3.0
Label	Metal	PET	0.4

3. Three parts that cannot

Wall from 3.0 mm to 2.6 mm saves 6.8 yuan, the most tempting line on the sheet. Drop ten samples corner-first from 1.0 m on six faces: no 3.0 mm case cracks, three of the 2.6 mm cases open a corner crack past 15 mm. Losing 0.4 mm takes 34% off the section modulus, not linearly.

Two latches down to one saves 3.2 yuan, but a latch is a clamp, not a switch: two hold the gasket at 30% compression, one holds 22%. Under 5 kPa vacuum for 60 s, the single-latch sample loses vacuum at 18 s.

The valve costs 1.8 yuan and the case still closes without it; the failure arrives after transport, where a 40 ℃ swing each way lifts opening force from 12 N to 30 N and pushes the gasket 1.2 mm into its groove. All three fail after the factory gate.

Part	Yuan	Failure
Wall	6.8	Crack 15 mm
Latch	3.2	Gasket 22%
Valve	1.8	Force 30 N

Together they release 11.8 yuan, six points on top of 8.1%. Sign it away and protection class, drop height and airtightness fail at once. Save on attachments, not on load, seal or pressure.

4. Eight points saved, point eight paid

Cut all five and the case saves 16.1 yuan, 8.1%. Two batches of one model ran a full 12 months: 1.9% returned for repair against 2.7% on the downgraded batch, a gap of 0.8 points. Small, but the only measure that puts saving and payout together.

Case cost down sample case open on white with a black egg-crate lid foam and a red cut foam insert behind two front latches

At 20,000 cases a year the saving is 322,000 yuan. Repairs rise by 160 cases at 85 yuan each, 28 yuan of it freight, so 13,600 yuan goes back out and 308,400 yuan stays.

The extra repairs are uneven. Wheels take 55%, liner 20%, surface 15%, packaging 10%, label 0. The label returns nothing yet drew 6 complaints: it does not look like the previous case. Repair cost hits after-sales, complaints hit repeat orders, and two points of repeat rate cost more than 13,600 yuan.

Part	Yuan	Repairs	Net, 20k
Wheels	4.2	55%	76,520
Liner	6.0	20%	117,280
Surface	2.5	15%	47,960
Packaging	3.0	10%	58,640
Label	0.4	0%	8,000

5. Validation before release

None of the five goes live on signature: four close on a bench, one only by sampling. Wheels run 5 km of towing plus 200 stair trips, and past 0.5 mm of wear they go back to 70 mm. The liner takes three 1.0 m six-face drops at 10 min intervals, then three samples sit at 25% compression for 22 h, where anything over 15% set returns to EVA.

Surface takes 200 wipes at 500 g plus 24 h of neutral salt spray, and a gloss shift above 10 units fails. Packaging takes a 72 h six-high stack, where crush beyond 4 mm means an extra board.

The label is the hard one: 24 h at 60 ℃, 24 h at −20 ℃, 20 wipes with anhydrous ethanol, all three before an export batch. The first run is 30 cases, 10 pulled for the full set. A part that fails becomes a conditional downgrade, limited to one model or one delivery radius.

6. Perception ranking and the crossing line

What the customer notices runs opposite to what fails: the label is seen first and returns zero repairs, packaging is barely seen and carries 10%. By perception the order is label, surface, wheels, liner, packaging; by risk it reverses.

Leave the strong-perception parts alone and the first impression holds; weak-perception parts are where savings live, because packaging and liner only show after unpacking or dropping.

There are three crossing lines: wall below 3.0 mm with a 1.0 m drop requirement, fewer than two latches on an IP67 product, no valve where transport swings past 40 ℃. Cross one and this is another model, with new certification and drawings. No combination of the five alters the protection class, because none carries load, seals the joint or balances pressure.

Conclusion

Write the grading down before the meeting. Movable: wheels, liner, surface, packaging, label, 16.1 yuan and 8.1%, a net 308,400 yuan at 20,000 units. Fixed: 3.0 mm wall, two latches, valve, 11.8 yuan that walks the case out of its protection class. Judge with one ratio, yuan saved over added repair cost, and it must clear 6: wheels 11.2, liner 44.1, surface 24.5, packaging 44.1. Close four runs first: 5 km towing with 200 stair trips, three 1.0 m drops, 200 wipes plus salt spray, 72 h stacking, and 24 h at 60 ℃ and −20 ℃ for the label. Pass all four and sign; fail one and it is a conditional downgrade.

This article discusses container-side specifications and design implications only, and does not cover any handling, loading or use of the contents.