Do plastic storage cases for instruments always need IP67?

Answer: Only the vehicle and long-term tiers do. A fixed bench case indoors is served by IP54, and extra sealing buys nothing.

Answer: EVA at 30 kg/m³ under 2 kg, PE at 45 kg/m³ above 5 kg, where compression set matters more.

Why are dissipative cases almost always black?

Answer: Carbon black is the cheapest stable filler, reaching the range at 8 to 12 percent; light colours need conductive fibre.

Does every case need a desiccant pack?

Answer: Long-term stores do, at 10 g per 10 litres. In daily transfer the pack saturates in weeks.

Will five stacked cases crush the bottom one?

Answer: At 25 kg each the bottom carries 100 kg static, which a 3.0 mm wall handles below 30 days.

Plastic Storage Cases for Instruments: Where They Are Used

Quick answer: Plastic storage cases for instruments split into four tiers: fixed bench, in-building transfer, vehicle and field, and long-term store. Configuration differs in cavity and foam, static control and desiccant, latch and stacking. Pick the tier wrong and every later specification is wrong.

How Plastic Storage Cases for Instruments Split by Scene
Benches and Production Cells
Field Work and Mobile Inspection
ESD, Moisture and Temperature Control
Turning a Scene into Four Spec Fields
FAQ

1. How Plastic Storage Cases for Instruments Split by Scene

Sorting by industry fails: the same box is a lab case at a calibration house and at a power plant, yet one carries a moisture barrier. Moves per year, shelter and dwell time separate them: bench cases travel under 20 times indoors, transfer changes floor weekly, field work adds rain and dust, stores stay shut six months.

Tier	Moves per year	Exposure	Focus
Fixed bench	under 20	indoor	open access, labels
In-building	100 to 300	indoor, lifts	handle, stacking
Vehicle, field	over 50	dust and rain	seal, latches, foam
Long-term store	under 5	ambient	desiccant, stacking

2. Benches and Production Cells

Access speed governs the bench. Plastic storage cases for instruments used at a workstation need a cavity 150 to 180 mm deep, so the unit stands upright and fingers close on the body from the top edge.

Plastic storage cases for instruments: closed off-white case with light blue latch seated in a recessed keeper, rounded corner and fine lid seam

Foam follows mass: EVA at 30 kg/m³ below 2 kg, PE at 45 kg/m³ above 5 kg where compression set matters. Two strips 40 mm wide with a 10 mm gap form three bays.

Colour marks calibration state, and the hinge stop must hold past 100 degrees or the lid drops on a hand.

3. Field Work and Mobile Inspection

Seal first, vibration second. An IP67 build uses one moulded gasket compressed 30 to 40 percent; less leaks, more takes a set, and a day of driving can walk a latch open.

Foam and body share the damping: travel stays under 2 mm, a light 1 to 2 mm press rather than a drop-in. Four feet 8 mm high keep the base off grit.

The grip measures 25 mm across so a gloved hand can carry a full case of instruments, and markings sit in the moulding, not on a label that lifts in two seasons.

4. ESD, Moisture and Temperature Control

Static, moisture and temperature take three separate answers, and none substitutes for another.

Plastic storage cases for instruments: light blue lid open on a white body, blue gasket in the rim, rolled blue cloth and white cloth inside

A dissipative body holds 10 to the 6th to 10 to the 9th ohm with carbon black at 8 to 12 percent, hence the black colour; a grounding tab under 10 ohm makes it work.

Desiccant runs at 10 g per 10 litres to hold the cavity under 30 percent relative humidity. Temperature is buffered only: a 10 mm XPE liner slows drift from 40 to 5 degrees Celsius from 3 to under 1 degree per minute.

5. Turning a Scene into Four Spec Fields

Cavity size on plastic storage cases for instruments is internal, never external. A 500 by 400 by 220 mm case gives 440 by 340 by 180 mm inside, measured 20 mm below the rim where draft narrows it.

Walls take a nominal and a floor, 3.0 and 2.7 mm, with 3.6 mm at a rib root. Five stacked cases of 25 kg put 100 kg on the bottom one; dynamic load is a 1.2 m drop on six faces.

State the condition, not the verdict: cold drop after 4 hours at minus 20 degrees Celsius, hot storage 48 hours at 60, damp heat 96 hours at 40 and 93 percent relative humidity.

Field	How to write it	Common error
Cavity	440 by 340 by 180 mm, 20 mm below rim	outside size only
Wall	3.0 mm nominal, 2.7 mm minimum	thickened, no figure
Load	100 kg at five high, 1.2 m drop	50 kg, no mode
Test	drop after 4 h at minus 20 degrees	no preconditioning

Conclusion

Most specification arguments trace back to a scene that was never tiered. Once it is fixed, seal, foam, static control and desiccant land on defined requirements. Choosing a shape first and fitting the scene to it fails at the first rainy season. Put moves per year, exposure and dwell time into the enquiry and quote by tier; that sequence holds better than any parameter table, and it is the discipline behind plastic storage cases for instruments.

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.