When is a Case Internal Divider the wrong choice?

Answer: Cavity under 40 mm, items over 8 kg with a boss, batches under 20, or wash-down cleaning. Any one rules slats out.

What cell tolerance can a Case Internal Divider hold?

Answer: 1.2 mm, since accuracy comes from slot placement; as moulded pockets the same geometry reaches 0.3 mm, which decides whether foam is needed.

Can 25 density PE replace 45 density EVA?

Answer: Not above 2 kg or 60 C, where PE takes 15 percent set over 72 hours and a collapsed pad needs thicker foam.

Do slats make sense for odd shapes under 5 pieces?

Answer: Barely; the die cost does not spread over five units, so use egg crate with labels.

Can moulded pockets and slats be combined?

Answer: One direction only: pockets in the base, slats in the lid, since a shallow lid leaves no groove room.

How do you stop mixed kits from being assembled wrong?

Answer: Three colours on slat ends plus a card in the lid pocket. Past three kits, each needs its own case.

Why a Case Internal Divider Is Not Always the Answer

Quick answer: A Case Internal Divider pays off above 20 pieces and below two layout changes a year. Past 3000 pieces with a frozen layout, moulded pockets tighten tolerance from 1.2 mm to 0.3 mm and win on cost. Under 5 pieces a thermoformed tray ships the same day.

Every Case Gets Slats, the Most Common Mismatch
Overmoulded Pockets: Only Past 3000 Pieces
Two Foams: 45 Density Against 25 Density
Odd Shapes Under 5 Pieces: Trays and Egg Crate
Four Cases Where Slats Are the Wrong Answer
Mixed Kits: Where One Cell Can Serve Two
FAQ

1. Every Case Gets Slats, the Most Common Mismatch

Slats are the default because they are cheap, quick to revise and sample in three days. They separate cell from cell but do not hold an item still inside one, and the foam that does costs another 8 to 15 mm of depth.

Method	Tolerance	First article	Batch	Weak point
Slat Case Internal Divider	1.2 mm	3 days	Over 20	Foam still needed
Moulded pockets	0.3 mm	45 days	Over 3000	New mould per change
Routed EVA block	0.5 mm	5 days	5 to 500	Bonding for deep cavities
Thermoformed tray	0.8 mm	7 days	Over 200	Height limited
Egg crate only	No cell	1 day	Any	No zoning

Ask batch first, tolerance second, price last.

2. Overmoulded Pockets: Only Past 3000 Pieces

A mould for a 300 by 200 mm pocket set costs 80,000 yuan: 26.7 yuan a piece at 3000 off, 267 at 300 off. What pockets sell is tolerance: 0.3 mm, no foam, R2 corners that hold no dust.

Case Internal Divider: one matte black moulded case facing forward on white, lid closed, handle raised, an orange latch clip at each end

The cost hides in revisions: move one cell and the mould changes, 45 days, against 3 for slats. Once cut, a pocket mould pins that layout for three years.

The mould fee is not the barrier; the revision cycle is.

Pockets suit a product frozen for three years above 5000 units a year; a case that changes twice a year stays one layout behind.

3. Two Foams: 45 Density Against 25 Density

Both are ordered as foam; recovery differs by a factor. At 25 percent compression over 50 cycles, 45 density EVA returns 96 percent against 87 for 25 density PE, so the item sits 1.4 mm lower after every closure.

Item	45 density EVA	25 density PE
Recovery, 50 cycles at 25%	96%	87%
Set after 72 hours at 60 C	6%	15%
30 mm thick, 20 kg static	1.2 mm	2.6 mm

The trade is not only price. EVA at 45 costs about 30 percent more, but its set is a quarter of PE, so the pad does not collapse. Mixed builds bond 45 as base against 25 as lining, a 30 mm sandwich costing 12 percent over all-PE; glue the full face, or the layers shear.

4. Odd Shapes Under 5 Pieces: Trays and Egg Crate

Under 5 pieces, cells are routed per item at 300 yuan a die, or 60 yuan a piece. A 0.8 mm PETG tray folded by hand ships the same day, and thermoforming overtakes slats past 200 pieces.

Case Internal Divider: one cobalt blue moulded case front on against white, lid shut, handle raised, red latch clips engaged, twin feet and ribs

Egg crate is the other retreat: 30 mm peaks at 40 percent compression wrap an item for under 3 yuan, but lifting one of two stacked items drags the other up.

The boundary is clean: egg crate for a shape that changes every batch, a tray above 200 pieces, a Case Internal Divider between 20 and 200.

5. Four Cases Where Slats Are the Wrong Answer

Cavity under 40 mm. A slat leaves 30 mm, minus a 4 mm groove, so it holds nothing; use a tray with a crimped edge.
Items over 8 kg with a boss. The boss bends the slat sideways; use a clamp plate and two 25 mm straps.
Batches under 20 with a new layout each time. Stock and mis-assembly cost more than the saving.
Wash-down cleaning. Slots trap chips no nozzle reaches; moulded corners solve it.

Three of the four are about batch size, none about price.

6. Mixed Kits: Where One Cell Can Serve Two

One shell carrying two kits means full-height long slats, half-height cross slats and a 2 mm PP pull-out sheet; pull one slat and two cells become one, in 40 seconds, and three colours on the ends drop mis-assembly from 3 percent to 0.2. Limits apply: a half-height slat stays above half the cavity depth or items tip, the groove belongs in the long slat rather than the wall, and past three kits colour coding fails. Where both heights coexist, the lid rib must bear on the full-height tops, or the lid stays ajar.

Conclusion

Between 20 and 200 pieces a Case Internal Divider is cheapest; past 3000 with a frozen layout, pockets trade a 45 day cycle for 0.3 mm. Draw those lines and a Case Internal Divider stops being a reflex.

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.