Can one dimension of a custom plastic box tier change on its own?

Answer: Length moves ±15 mm with an insert change alone; width and height need a new tool. Rim flatness still drifts about 0.2 mm, so the first article is measured again.

What is the minimum order quantity?

Answer: 500 pieces for a colour change on a shared mould, 1,000 for a new tool.

How much will a 2.0 mm custom plastic box hold?

Answer: 5 kg per unit is comfortable, the bottom box is checked at 35 kg eight high, and drop height is 1 m. Above 5 kg, go to 2.2 mm with crossed base ribs.

How is lead time scheduled?

Answer: Two days to first article, 8 days to pilot batch, 15 days to volume; a new tool adds 15 to 20 days.

Does a box without a gasket keep water out?

Answer: No. After a 30-minute rain test the interior shows water marks, so it is dust-tight at best. Water needs an EPDM cord and a 2 mm lip.

Custom Plastic Box Specifications: Size, Wall Thickness, Load

Quick answer: A custom plastic box is specified tier first, lid second, load and latch last. Four cavity tiers cover the range, the lid sets stiffness, filled weight decides wall thickness, and cavity tolerance is ±0.8 mm.

How Custom Plastic Box Specifications Split Into Size Tiers
Lid Structure and Wall Thickness Set Stiffness
Load Ceiling and Stacking Height
Latch Count and Rim Sealing
Sampling Parameters and Acceptance List
FAQ

1. How Custom Plastic Box Specifications Split Into Size Tiers

A custom plastic box is not continuously adjustable, so tier comes first. Four cavities cover 100×70×30, 140×100×45, 180×130×60 and 240×170×85 mm, about 1.8 times apart in volume, which keeps selection to one decision rather than a dozen near-identical sizes.

The envelope is cavity plus two walls plus a 3 mm rim flange, so a 180×130×60 cavity at 2.0 mm lands near 192×142×70 mm. Flanges below 2.5 mm warp as the lid closes, and shrinkage of 1.5 to 1.8% already moves a 240 mm box by 0.7 mm.

Outside mm	Cavity mm	Wall mm	Empty mass g	Load kg
110×80×38	100×70×30	1.8	78	3
152×112×54	140×100×45	2.0	132	5
192×142×70	180×130×60	2.2	205	8
254×184×96	240×170×85	2.5	320	12

2. Lid Structure and Wall Thickness Set Stiffness

The lid collapses first: a 2.0 mm flat lid sags 0.9 mm under 5 kg at the centre, a 2.5 mm ribbed lid 0.4 mm, a 2.8 mm stepped lid uses one fold, a 3.0 mm flanged lid serves the 240 mm tier.

Custom plastic box: orange box open and empty, ribbed lid interior, moulded dividers in the base, two front latches and one side latch, centred handle

Hinges match the lid: a thin integral hinge suits boxes under 160 mm at 5,000 cycles, a double-pin hinge reaches 8,000, a metal pin under a flanged lid 12,000. Below 1.5 mm at the root, the third drop cracks it.

Keep the closed gap under 0.5 mm, or the rim pinches fingers and dust enters. Lid ribs must run along the length, since cross ribs mostly see shear.

3. Load Ceiling and Stacking Height

Load splits into the single unit and the stack. A custom plastic box carries 3, 5, 8 or 12 kg across the tiers with base deflection under 0.8 mm, beyond which the base dishes on a shelf and each extra layer sinks deeper.

Stacking is 8 layers, 48 hours at 23 °C, side-wall deflection under 1.5 mm, drifting to 2.2 mm at 40 °C, so either six layers or two crossed base ribs at about 6% more cost. Drop testing is 1 m over ten impacts, where moving the corner radius from R1.5 to R3 lifts pass rates from about 70% to over 90%.

4. Latch Count and Rim Sealing

Latches are lighter than on a large case: one below 160 mm, two from 160 to 220 mm, two plus a side catch above. A custom plastic box is carried by hand, so opening force sits at 35 to 60 N; beyond that users pull with both hands and distort the rim.

Custom plastic box: grey box open close up, black foam insert with a long cut-out exposing a silver panel, latch bodies, metal hinge pins

Sealing has three levels: none for dry storage, a single 2.5 mm EPDM cord to IP54, a double cord with a 2 mm lip to IP65. POM catches lose under 15% of their opening force after 8,000 cycles, against nearly 30% for PP.

5. Sampling Parameters and Acceptance List

First articles run 30 pieces at 38 °C mould temperature, 225 °C melt, 38 MPa packing and 12 s cooling, and a four-cavity tool cycles in about 26 s.

Item	Value	Method
Cavity dimensions	±0.8 mm	Caliper, three points
Rim flatness	0.4 mm	Surface plate and feeler
Wall thickness	±0.12 mm	Ultrasonic, five-point mean
Latch opening force	35–60 N	Push-pull gauge
Stacking	8 layers, 48 h, ≤1.5 mm	Ambient load
Hinge cycling	8,000 cycles, no crack	Cycling rig

Fix the datum: cavity from the inner base, envelope from the outer base, or ±0.8 mm becomes 1.5 mm at assembly.

Conclusion

The difficulty is not one number but the match between tier, lid, load and latch. Fix the cavity tier and its ±0.8 mm tolerance, choose lid and hinge from the load, then close with latch force and sealing. A custom plastic box is judged on holding small dimensions, not on being made bigger.

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.