Why can the Military Communication Equipment Case not use fewer holes?

A: Count follows the interfaces on the panel. What can be controlled is position and compensation: 40 mm pitch, 25 mm edge distance, 3 mm boss.

Can the 20 mm gasket simply be widened?

A: Past 25 mm it covers the locating face of the boss and the bush will not seat flat. 20 mm at 25% compression is the usable point.

How thick must the lid of the Military Communication Equipment Case be for 4 tiers?

A: The same 4.0 mm wall, with ribs holding mid-span deflection over 1.2 m under 3 mm. Going to 5 mm adds 0.9 kg and helps less.

Why place the cable ports 45 mm above the base?

A: Lower and a wet floor enters, higher and the cable drapes onto the holes as a new leak path. 45 mm is the band left between gland diameter and base radius.

What does −30 °C to 65 °C do to the gasket?

A: Compression set grows across that range, so 25% has to carry 3% margin, or recovery runs short when hot and the rubber stiffens when cold.

Military Communication Equipment Case

Quick answer: The Military Communication Equipment Case sets openings against sealing: 6 cut-outs of φ12 mm and 2 cable ports still have to hold IP67 at 1 m for 30 min.

Three setup states and one opening conflict
Carried: keeping one face closed
Vehicle-mounted: four latches and four tiers
Deployed: making up for six cut-outs
Two cable ports and a 20 mm gasket
FAQ

1. Three setup states and one opening conflict

The Military Communication Equipment Case works in three states that ask the wall for different things: no opening on the back when carried, corner straps and 4 tiers when mounted, panel holes and cable exits when deployed. The three meet on one shell of 580×420×260 mm, and the conflict condenses into one rule: every hole removes a stretch of seal.

The wall is 4.0 mm, the cavity 520×360×215 mm, the empty weight 7.1 kg. Half of that wall exists for the holes: 25 mm from a cut-out to the outer wall, 40 mm between holes, and after 6 holes of φ12 mm across a 520 mm face, what remains is the perimeter a gasket can press on.

Setup state	Opening requirement	Sealing and shielding
Carried	No hole on the back face	Gasket continuous all round, never cut
Vehicle-mounted	4 latches take the load	Straps run in external channels, not through the wall
Deployed	6 panel holes of φ12 mm, 2 cable ports	Raised bosses, pressed bushes, clamped glands

2. Carried: keeping one face closed

Carried, the Military Communication Equipment Case has one demand: no hole on the face that touches the back. A 7.1 kg empty shell wants its centre of gravity 30 mm below the mid line of the back plate, or it swings while the carrier walks.

A 4.0 mm wall across 520×360 mm bulges about 2.3 mm under 100 kg of side load; two ribs 8 mm high bring that to 0.9 mm, keeping the gasket at 25% compression.

Military Communication Equipment Case in navy blue open upright, lid foam holding vials, syringes and infusion bags, gauze rolls in the base trays

Corners are weak points: a fold reaches only 70% of the straight-run compression, so each corner is drawn as an R12 arc.

3. Vehicle-mounted: four latches and four tiers

Vehicle-mounted, the Military Communication Equipment Case takes strap pressure and the weight above it. The 4 latches rate 450 N each, 1 800 N together, back-calculated from braking inertia with a 1.5 safety factor.

Load point	Condition	Value
Strap channel	0.8 g braking	12 mm deep, bearing on the rib
Lid centre	4 tiers stacked	Under 3 mm over 1.2 m
4 latches	1.2 m drop	450 N each, 1 800 N total

At 4 tiers the bottom lid carries 75 kg; past 3 mm of deflection the stack leans.

Straps on the Military Communication Equipment Case must not pass through the wall: two channels 12 mm deep keep webbing on a stiffening rib, not the sealing face. That is what pushes all panel holes onto the front and top faces.

4. Deployed: making up for six cut-outs

The 6 panel holes of φ12 mm are the heart of the conflict. IP67 means 1 m of water for 30 min, and every hole adds perimeter with no gasket over it: the six add about 226 mm of rim, close to 11% of the 2 000 mm outline.

The fix is to treat each hole as local structure. A boss 3 mm high is raised at the rim, a brass bush is pressed in flush, and anaerobic adhesive fills the gap between bush and bore. A 2 mm flat outside the boss gives the gasket a face, so each hole turns from a free edge into an enclosed ring.

Layout on the Military Communication Equipment Case follows the seal too: 2 rows of 3 holes, 40 mm apart on centres, the outer hole 35 mm from the wall edge, and a 60 mm solid band between rows so the gasket runs straight through.

The 120° lid angle comes from the deployed state: 180 mm of clear space between lid inner face and rim, while below 110° the lid edge presses on the top-row bush.

Military Communication Equipment Case olive green open on a wooden bench, four barcoded paper packs in foam, one empty cavity, warehouse shelves behind

5. Two cable ports and a 20 mm gasket

In the Military Communication Equipment Case the 2 cable ports matter more for position than count. Both sit low on the rear wall, 45 mm above the base: higher and the cable drapes across the panel holes, lower and the port enters first on a wet floor. Each is a clamped gland with the collar compressed 30%.

The 20 mm conductive gasket is the compromise. Under 15 mm the contact area is too small to bridge a rim; over 25 mm the gasket covers the locating face of the boss and the bush cannot seat flat. At 20 mm the compression is 25%, 5 mm of squeeze, which recovers between −30 °C and 65 °C.

Opening	Size	Sealing and shielding value
6 panel holes	φ12 mm, 40 mm pitch	3 mm boss, pressed bush, gasket bridging 20 mm
2 cable ports	φ28 mm, 45 mm above base	Clamped gland, collar compressed 30%
Rim seal	About 2 000 mm perimeter	Gasket at 25% compression, R12 corners

The three openings must be tested together. A leak test on the holes alone passes, and so does a soak test on the ports alone; only 6 holes, 2 ports and the full rim in 1 m of water for 30 min show whether the gasket collapses on the 40 mm strip between holes.

The 1.2 m drop is the second line. A boss is local thickening and therefore a stress riser, so its root carries an R2 fillet and the wall goes from 4.0 mm to 5.5 mm locally, with no whitening at any rim after the drop.

Conclusion

The difficulty in the Military Communication Equipment Case is not the wall but every opening cut through it. With 6 panel holes of φ12 mm, 2 cable ports and a full rim on one 580×420×260 mm shell, the answer is a set of values: boss, bush, 20 mm gasket, 25% compression. Put them on the drawing and the conflict becomes inspectable.