What should be fixed first when choosing a Stackable Container?

Answer: Tier count and load per tier. Rim pressure follows from those two.

Does a four high stack always need a pad?

Answer: At 60 °C, yes: 0.06 MPa against 0.2 MPa allowed, and a 5 mm pad keeps set under 1 mm.

Can one case serve both forklift and hand placing?

Answer: Yes, if the entry suits the forklift; a 10 mm rim with a chamfer just seats harder.

Is the 600 × 400 mm module mandatory?

Answer: Only on a Euro pallet, where four fill 1200 × 800 mm at 92 percent.

Is a folding case always cheaper?

Answer: Only with a long empty return; 300 km twice a month clears it in a year.

How to Choose a Stackable Container: Five Tests in Order

Quick answer: Choose a Stackable Container by settling five things in order: tier count, drop method, handling interface, internal height and pallet module, and fold ratio last.

How Many Tiers a Stackable Container Can Take
Picking the Alignment Feature by Drop Method
Lifting and Fork Interfaces at Full Load
Internal Height and Pallet Module
Fold Ratio and the Return Trip
FAQ

1. How Many Tiers a Stackable Container Can Take

Tier count comes from load per tier. Put 25 kg in each tier and stack four: the bottom lid of a Stackable Container carries 75 kg from the three tiers above, not the 100 kg of the stack. Tare lands on the pallet.

Pressure sits on the rim band. A 600 × 400 mm case with a 6 mm rim land gives about 12000 mm², so 75 kg becomes 0.06 MPa. Polypropylene allows 0.4 MPa long term at 23 °C and 0.2 MPa at 60 °C, so the same stack turns marginal in a hot store.

Tiers	Load on bottom lid	Rim pressure	Set after 3 months at 60 °C	Verdict
2	25 kg	0.02 MPa	0.4 mm	fine anywhere
3	50 kg	0.04 MPa	0.9 mm	fine at room temp
4	75 kg	0.06 MPa	1.7 mm	needs a pad
5	100 kg	0.08 MPa	2.8 mm	not advised

Time counts too: 24 hours shows nothing, three months separates cases.

2. Picking the Alignment Feature by Drop Method

The alignment feature follows the drop method: hand placing gives about 3 s to line up, so the entry must swallow a 15 mm error, which a 90 degree taper opening 10 mm wider does.

Stackable Container: a black case on a timber pallet, two webbing straps pulling down over the lid, pallet on a warehouse conveyor between tall racks

Forks stop within 50 mm and land within 30 mm, so a 10 mm rim with a lead-in chamfer keeps the upper case inside. A crane swings 100 mm and needs a large cone. Where all three occur, size for the loosest.

3. Lifting and Fork Interfaces at Full Load

Forks need a pocket. A 100 × 200 mm pocket leaves 20 mm around an 80 mm tine, and a pocket in a base skid outlasts a slot in the body: at 380 kg the slot dents 1.5 mm and cracks within a few dozen moves.

Crane work needs rated eyes. Four at 1.2 kN each, with sling angle at 60 degrees, put 1.07 kN on each leg, a 12 percent margin. At 90 degrees each leg sees 1.33 kN, past the rating.

Handling	Interface	Full load limit	Commonly missed
Hand carry	side grips 25 mm deep	20 kg per case	grips near centre of gravity
Forklift	base pocket 100 × 200 mm	380 kg	forks over two thirds of length
Four point lift	four eyes at 1.2 kN	300 kg at 60 degrees	derate above 60 degrees
Pallet load	pallet plus stretch film	700 kg	film holds shape, not weight

Interface marks belong on the same face as stack marks, or forks go in backwards.

4. Internal Height and Pallet Module

Internal height is subtracted from outside height, never added up from inside. A 320 mm case spends 35 mm on the lid and 8 mm on base plus stack boss, leaving 285 mm; a 20 mm EVA liner brings usable height to 245 mm.

Stackable Container: black cases stacked three high on a timber pallet, two vertical straps around the whole stack, blue steel columns behind

The module is set by the pallet: four 600 × 400 mm cases fit 2 × 2 on 1200 × 800 mm at 92 percent area use, five fit on 1200 × 1000 mm at 88 percent. Change the internal height and the outside follows, so lock both first.

5. Fold Ratio and the Return Trip

Fold ratio comes last. A 305 mm case folding to 95 mm gives 1:3.2, so a return load goes from 240 to 720 units and saves a couple of yuan each, but only if empties travel far back.

Folding costs something: the crease runs 0.3 mm thinner and whitens after 500 cycles, a folded stack is one tier less stable, and price is 18 percent higher. On one way traffic no fold is needed; returns over 300 km twice a month clear the premium in a year.

Conclusion

Tier count fixes rim pressure, drop method the entry, full load the pockets and eyes, then height and module lock, and fold ratio trades last. Hold the order and the Stackable Container you pick survives the floor.

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.