Core Carrier Formed R9.

Research record

The detail behind
the study.

Source-linked work for this revision. Reported checks describe the stated model or test; physical qualification and applicability to the current retrofit remain separate.

R9 replaces the R8 mixed-thickness sharp return with a continuous nominal 4 mm section. The return has inside radius 4 mm and outside radius 8 mm, across a 24 mm width. Its bend center is local Y -309, Z -2. This is an explicit nominal formed construction, not a qualified bending process or released flat pattern.

The thicker foot moves the captive screw underhead from Y -316 to -317. Its neck increases from 12 to 13 mm, retaining the nominal 6 mm engagement and the checked 7 mm release travel. The R8 stud and slot clearances are retained.

Two focused tests passed in 79.45 seconds. Nominal fit/export, motion, compartment and formed-return checks pass. Full CAD regression for R9 passed: 336 tests in 1770.56 seconds. This does not cover R10. A source copy in a separate locked dependency environment reproduced all 81 STEP bodies with zero Boolean symmetric difference. Prior R8 and R7 test results must not be represented as R9 results.

Material and grain direction, bend tooling, bend allowance, springback, dimensional capability, corrosion protection, loads, threaded retention and physical assembly still require definition and verification. No flat pattern is released. Electrical components, wiring and full-system manufacturing qualification remain incomplete. R9 addresses the geometric thickness/radius inconsistency; it does not make the enclosure manufacture-ready.

Formed carrier lock-hole sensitivity

The R9 nominal return is geometrically defined, but its lock hole has little margin in the studied forming-error stack. The worst calculated radial gap is 0.0128 mm, below the proposed 0.10 mm target. Positive clearance in this simplified calculation is not proof of reliable physical assembly.

The study uses a 4.5 mm hole and 3 mm screw neck, adds the prior size/coating assumptions, and combines an illustrative +/-1 degree bend-angle error with +/-0.381 mm transverse forming displacement and a separate +/-0.10 mm position allowance. An inclined hole also reduces clearance because the fixed screw intersects its faces elliptically. Both plate faces are checked.

SendCutSend's published bending tolerances provide the angle and single-flange dimensional reference. Applying the latter as transverse hole displacement is an explicit engineering sensitivity assumption, not a promised vendor tolerance or a selected process. Correlation, material, tooling and actual hole location capability remain unresolved.

Next revise or accommodate the foot-hole clearance and recheck head/retainer support, or establish a tighter verified forming or post-form drilling process. Head bearing, retainer behavior, threads and load capacity are outside this local bore calculation. Current R9 CAD is unchanged.