Why is the divider wall fixed at 2.8 mm instead of thinner?

A: Below 2.4 mm the Professional drone combo multi-battery hard case sees its wall bow toward the neighbouring bay at 55 °C and lose clear width; 2.8 mm keeps drift inside 0.35 mm after 20 thermal cycles without the root sink mark that extra material brings.

Why 20 thermal cycles instead of 10?

A: The first ten cycles bleed off injection residual stress, so readings move quickly; from the tenth onward the curve flattens and the last ten confirm the return difference stops growing.

Do the drop recheck and the thermal test measure the same thing?

A: No. The thermal test reads drift after 20 cycles from −20 °C to 55 °C, while the drop recheck reads whether a 1.0 m six-face impact pushed the bays open. Both must sit inside 0.35 mm to release, but one measures heat and the other force, logged in separate columns.

Does gasket compression relate to bay spacing?

A: Not directly, yet both share one closing chain. A step drop too large stops the two 350 N latches finishing travel, the gasket never reaches 20 % compression, and the divider gap returns with it, so spacing scatters and closing must be verified as a whole.

Professional drone combo multi-battery hard case

Quick answer: A Professional drone combo multi-battery hard case holds drift under 0.35 mm after 20 cycles from −20 °C to 55 °C, measured on 2.8 mm divider walls.

Divider wall thickness of the Professional drone combo multi-battery hard case
The step drop inside the lid
Spacing readings after thermal cycles
Cell-position retention in the drop recheck
Wall-thickness scrap limit for multi-battery batches
FAQ

1. Divider wall thickness of the Professional drone combo multi-battery hard case

The Professional drone combo multi-battery hard case is moulded to a 560×400×230 mm outer envelope and a 495×340×165 mm inner cavity, with the shell held at a uniform 4.0 mm. Seven bays are cut by six dividers injected in the same shot as the base, each with its own 2.8 mm wall.

2.8 mm is a floor reached after repeated trials: at 2.4 mm a wall bows toward the neighbouring bay in the 55 °C segment and eats into clear width, while at 3.2 mm the root junction piles up material, cools slowly and pulls a sink mark that tilts the spacing datum. JUNZHIJIA takes three readings up each wall on the first article and releases only inside a 0.12 mm spread. The 5.3 kg empty weight is the first witness the Professional drone combo multi-battery hard case has drifted; a reading 0.15 kg off halts the line, and the 11 kg load is spread across four side walls and base ribs, never onto the dividers.

Wall grade	Root sink mark	Clear-width verdict
2.4 mm	none	bows when hot, width lost
2.8 mm	none	drift within 0.35 mm after 20 cycles
3.2 mm	visible	datum tilted, scrap

2. The step drop inside the lid

Inside the lid of the Professional drone combo multi-battery hard case, an 11 mm limiting step above each divider presses the wall tops down once closed and locks all six vertically. Mould shrinkage leaves the real drop 0.1–0.2 mm short of the steel, so the tool is cut at 11.15 mm and the allowance stays in the steel rather than being shimmed at assembly.

Professional drone combo multi-battery hard case olive long closed shell on steel bench, kraft sleeves under the slightly raised lid, several catches, racking behind

Too little drop leaves a gap that lets a divider rock about its root and scatter the spacing readings; too much stops the lid short of seating, so the two latches cannot finish travel and the gasket never reaches 20 % compression. A depth gauge at the four corners must read 10.95–11.05 mm to pass.

3. Spacing readings after thermal cycles

The Professional drone combo multi-battery hard case runs −20 °C to 55 °C for 20 cycles with a 1 h soak at each segment, excluding transfer time. Clear width between adjacent dividers is taken at the top edge and the root, logged bay by bay to 0.01 mm on a digital caliper; first and last readings are subtracted after 20 cycles to give drift, accepted at 0.35 mm or less.

Drift does not arrive in one step: residual stress bleeds off over the first five cycles, then the curve flattens from the tenth, so closure depends on the last ten cycles' slope rather than the total.

Thermal cycle	High-segment gain	Cumulative drift
Cycle 1	datum	0 mm
Cycle 10	+0.14 mm	0.14 mm
Cycle 20	+0.30 mm	0.30 mm

4. Cell-position retention in the drop recheck

A sample clearing thermal cycling takes a 1.0 m six-face drop closed with 11 kg ballast and both latches, touching base, lid and all four edges once; dividers are not re-adjusted, and width is measured straight away to see whether impact reopened the flattened spacing. The Professional drone combo multi-battery hard case gets one orientation sequence only — a repeat would whiten the root fillet first and the reading would reflect damage rather than springback.

Professional drone combo multi-battery hard case white open shell on stainless bench, flat dark lid foam, white dividers holding blue-white packs and boxed modules

Two features hold attention: whether the root fillet whitened and whether the step impression shifted to one side. Even inside 0.35 mm, a shifted impression means restraint came from friction rather than step location, so the sample is rejected; a scribed datum line on the step face shows the shift. A 4500-cycle open-close run follows the drop on the Professional drone combo multi-battery hard case, with step drop measured every 500 cycles and any fall below 10.90 mm logged, because wear returns the vertical gap and a flattened spacing can scatter again.

Drift value	After thermal cycling	After drop recheck
≤0.25 mm	closes firmly	still closed
0.25–0.35 mm	acceptance edge	check the impression
>0.35 mm	scrap	does not enter recheck

5. Wall-thickness scrap limit for multi-battery batches

Stacking four readings, the Professional drone combo multi-battery hard case sets its scrap limit at three points: a wall spread above 0.12 mm, a step drop more than 0.10 mm off 11 mm, or drift above 0.35 mm after 20 cycles. Any one sends the batch back to the tool rather than being selected into compliance. Selective pairing can pass one case, yet carries the same mould bias into the next batch. Scrap is judged by batch, not by piece: the six dividers from one slide set are judged together, and one out-of-line wall sends all six from that shot back, since the fault is slide position rather than a single cavity.

JUNZHIJIA writes wall thickness, step drop and 20-cycle drift on one release-sheet line. One gasket sits in the lid groove at 20 % compression with groove depth back-calculated from cord diameter, and spray and dust run in the IP65 test order while the case only records whether the lid admitted water or dust, with no certificate number or grade conclusion.

Conclusion

The bay stability of a Professional drone combo multi-battery hard case starts at a 2.8 mm divider wall and an 11 mm limiting step, and lands on drift of 0.35 mm or less after 20 cycles from −20 °C to 55 °C. A 1.0 m drop recheck, 4500 open-close cycles and one gasket at 20 % compression close that chain across a batch. Writing wall thickness, step drop and drift on one release line is what makes multi-battery consistency reproducible.