Electronic control unit housing

Does the sealing rim of an electronics enclosure stay flat enough to close on a gasket?

An ECU housing has one interface that decides whether the box is watertight and several that decide whether the electronics fit. They are not the same surfaces and they do not move together.

The 3D run was solved from a rear-central inlet on a validated 959,021-tetrahedron mesh so that rim, channel floor, PCB posts and vehicle mounts can each be assessed on their own.

230.0 x 142.0 x 52.0 mm, 2.5 mm nominal wall, 162.862 cm3: 38 features with a lid seal groove, cored lid towers and PCB posts, rear connector skirts and pierced vehicle mounts.

A traceable engineering model.

Two-stage meshing: a Dual Domain surface first, then a 3D tetrahedral mesh generated from the corrected surface, so the screened inlet node survives into the 3D run. Gate position was screened on matched Dual Domain models, one inlet against two, before the 3D run was launched.

The 3D Fill + Pack + Warp run was solved with a single point inlet, a nominal one-second fill, switchover at 99 percent of part volume and a hold at 80 percent of filling pressure. Every plot keeps its original legend so each result can be read in its own units.

Read the result in context.

The enclosure fills in 1.041 s and the sealing rim is among the last regions to fill, at a V/P pressure of 49.72 MPa. The rim also sees less pressure than the central floor, which is the packing question in one sentence.

Volumetric shrinkage reaches 11.31 percent in the thick rim interiors, and the hottest interior point, 16.94 s to ejection temperature, is a wall-to-base mounting junction. The rear-side sink estimate peaks at 0.107 mm.

Total deflection is 1.493 mm, mostly inward at the side rim, with a 2.520 mm out-of-plane range across the part. The seal rim closes to a 1.369 mm residual against a fitted plane, so rim and channel floor both show bow.

From evidence to action.

Address rim shrinkage, the wall-to-base thermal delay and the rear-side sink as three distinct local changes rather than one global process move.

Set the gasket compression and the PCB fit requirements, then re-solve with a modelled feed and cooling system against those limits.