Is 8 h at 2 ℃ to 8 ℃ a unit figure or a batch figure?

A: Both. The unit carries the design, the batch carries the spread: the worst of 120 must sit inside 8 h and within 0.5 h of the best.

How is flatness of 0.3 mm measured?

A: Surface plate and feeler gauge, six points, largest difference. Let it settle at 20 ℃ for 2 h first.

Why can the φ18 mm port not be drilled later?

A: A drilled hole breaks the sealing face and has no boss, so it loosens fast. A moulded port carries a 1 mm chamfer and a hard stop that holds probe depth.

Does six-high stacking crush the 25 mm PU layer?

A: On a Medical cold chain insulated protective box wholesale batch, 88 kg over the lid is about 4.4 kPa, and PU at 25 mm recovers from 24 h at that load. Alignment is the condition: offset by half a position and the corners take shear.

Medical cold chain insulated protective box wholesale

Q: Can a Medical cold chain insulated protective box wholesale order start with 20 units?

A: Yes, if those 20 come from the same mould and resin lot, otherwise their curve means nothing. Cut three to confirm density in the 25 mm layer.

Quick answer: Medical cold chain insulated protective box wholesale: 520 × 380 × 300 mm, PU 25 mm, 120-unit MOQ, 3 sampled per batch, 2–8 ℃ held for 8 h.

What a wholesale order actually measures
How density tolerance in 25 mm of PU splits one batch
Lid flatness of 0.3 mm and gasket margin
Why the φ18 mm logger port fixes comparability
120 units, 3 sampled, six-high stacking
FAQ

1. What a wholesale order actually measures

Retail measures one box, wholesale measures the worst of 120. One unit at 520 × 380 × 300 mm outside, 440 × 300 × 225 mm inside, 4.0 mm walls and 25 mm of PU weighs 5.6 kg empty, carries 12 kg and holds 2 ℃ to 8 ℃ for 8 h. The same drawing and resin still give two curves once lid flatness drifts by 0.2 mm.

Wholesale step	What is checked	Recorded value
Sample	PU density, lid flatness	3 cut open
First article	Port position and depth	φ18 mm
Production	Batch temperature curve	120 units
Delivery	Stacking, drop	6 high, 1.2 m

On a Medical cold chain insulated protective box wholesale order, batch comes first. Three values set the line: density tolerance in the 25 mm PU layer, lid flatness at 0.3 mm, and the φ18 mm logger port position. None shows on a sample; all multiply by 120.

A sample proves the ceiling, never the floor.

2. How density tolerance in 25 mm of PU splits one batch

Thickness is 25 mm; density is separate. Edge-to-centre variation of 3% in one moulding is normal, and past 5% it shows at hour eight, when the thin patch conducts faster.

Medical cold chain insulated protective box wholesale unit open on white, egg-crate foam in the lid, slotted base tray, two draw latches

On a Medical cold chain insulated protective box wholesale run, 12 kg sits in the central zone and four 400 g ice packs stand at the walls, so the 25 mm layer is the only divider. With thickness and position fixed, spread comes from density and lid fit.

Grouping by mould number is the cheapest consistency step: one mould, one shift, one resin lot gives the narrowest spread, while mixed moulds put two foaming curves on one pallet. Within 3% the spread stays near 0.5 ℃; at 5% it opens to 1.2 ℃. Write 0.5 h into the contract rather than 8 h.

Consistency risk	Cause	Allowed drift
Hold time drops a step	PU density low	≤ 3% in the layer
Lid not seating	flatness out of spec	0.3 mm
Probe reads elsewhere	port position drift	φ18 mm
Corner crush on stack	wall thickness uneven	4.0 mm ± 0.2 mm

Density cannot be seen on a Medical cold chain insulated protective box wholesale line. Cutting three boxes per batch and weighing three plugs each is the only check that lands.

3. Lid flatness of 0.3 mm and gasket margin

On a Medical cold chain insulated protective box wholesale batch, flatness of 0.3 mm comes before any seal. The rim cools last, so warp pulls from four corners inward; past 0.3 mm the gasket loses contact mid-span and IP67 at 1 m for 30 min goes with it.

Two latches at 380 N sit on the long sides and leave 440 mm of rim unsupported, so rim stiffness alone holds the gasket. Each 0.1 mm of flatness error costs about 3% of mid-span compression.

That is roughly one thousandth of the span; measure on a surface plate at six points.

4. Why the φ18 mm logger port fixes comparability

The φ18 mm logger port is where comparability starts on a Medical cold chain insulated protective box. Placed 60 mm behind the lid centre line, the probe reads air; 10 mm off and it touches the wall, so two boxes from one batch report two curves.

Medical cold chain insulated protective box wholesale case open on grey, plain ribbed lid, foam slots left and a nine-cell empty grid right

The port cannot be drilled later: the hole cuts the sealing face and has no boss behind it, so it loosens after a few insertions. Moulded in place, it carries a 1 mm chamfer and a hard stop.

One port per Medical cold chain insulated protective box wholesale unit, three per batch, depth 45 mm from the inner lid face. Redraw it once and earlier curves are void.

5. 120 units, 3 sampled, six-high stacking

For a Medical cold chain insulated protective box wholesale order, a 120-unit MOQ with 3 sampled per batch is the smallest loop: first shot, middle, last.

Six-high stacking follows from the 520 × 380 × 300 mm outline and 17.6 kg packed weight. The bottom lid carries five boxes, 88 kg over 0.198 m², about 4.4 kPa. Corners decide the outcome: half a position of offset turns compression into shear.

A 1.2 m drop and IP67 are separate checks: corners and latches after the drop, water after 1 m for 30 min.

Control value	How it is measured	Pass
Flatness 0.3 mm	plate and feeler, six points	all within
PU 25 mm	three cut sections	mean on target
Port φ18 mm	go/no-go gauge	all pass
2 ℃ to 8 ℃, 8 h	continuous logging	≤ 0.5 h spread
Six-high stack	static load, 24 h	no permanent set

Both ends need a note: at −20 ℃ the PU stiffens and the 380 N latch has its thinnest margin; at 55 ℃ pressure rises, so do not open within 30 min.

Conclusion

A Medical cold chain insulated protective box wholesale programme is not about 8 h for one unit but about 120 units agreeing: density tolerance in the 25 mm PU layer, lid flatness at 0.3 mm, and the position of the φ18 mm logger port. Drift in any one of them puts two curves into one shipment. Sample three per batch every time and the batch becomes predictable.