The exposed pcb pads of J1 I think is not long enough. It should be long enough to penetrate a female usb connector. So you have to search for how deep they usually are
I’ll look up USB-A mating dimensions and compare them with the exposed length of J1 and the enclosure’s front edge. The important measurement is the unobstructed length from the PCB tip to the enclosure—not just the copper pad length.
Your concern is justified: the PCB currently projects only 5.35 mm beyond the enclosure, while the USB-A drawing specifies at least 11.75 mm from the plug tip to its housing shoulder. I also found that J1’s contact pads appear outside the saved PCB outline, so shortening the enclosure alone would not resolve the connector geometry.
The current enclosure leaves only 5.35 mm of PCB exposed in the insertion direction. This is too short to accept on the basis of the standard USB-A plug envelope. The earlier check that plastic ends before a J1 footprint boundary was not a USB mating check and must not be treated as one.
No PCB, copper, component placement, routing or enclosure geometry was changed during this research.
Sources and verified dimension interpretation
Primary geometry: Universal Serial Bus Specification Revision 2.0, Chapter 6, printed page 95, Figure 6-7 (Series A receptacle interface and mating drawing), and printed page 99, Figure 6-9 (Series A plug interface drawing). [Full specification mirror](https://alsa.mirrorservice.org/datasheets/usb/usb_20.pdf...
You’re right: the PCB projects only 5.35 mm beyond the enclosure, while the USB-A plug drawing specifies 11.75 mm minimum from the plug tip to the housing shoulder—not copper pad length.
I recommend targeting 12 mm of exposed tongue, approximately 6.65 mm more, while keeping the electronics covered; J1’s conflicting pad/outline coordinates must be resolved before changing the PCB, as detailed in USB-A Mating Clearance.
Should I proceed with that USB tongue revision and refit the enclosure around it?
Superseded dimensional record: The user explicitly authorized 1.2-mm skins and 0.5-mm gaps. The existing base/lid nodes now reference the ultra-thin assets. See low-profile-enclosure-revision for the current 5.81936-mm stack, asset links, validation and render. The older dimensions and asset table below are retained as revision history.
Delivery status — INCOMPLETE PROTOTYPE
Separate parametric base and lid have been compiled, uploaded, placed and read back successfully. The best candidate is visible in the project, but the enclosure is not accepted for physical use: the PCB can slide toward USB, and the population of the hidden J2 header is unresolved. No PCB, schematic, routing, component position or outline was changed.
Table
Assigned item
Status
Evidence / blocker
Inspect exact layout and package heights
Completed
Layout, all model assets and all 49 via positions inspected; physical J2 population remains unknown
Author two parameterized Build123d solids
Completed
Valid, single-solid base and lid; shared project datum and parameter headers
Upload and separately place under ROOT
Completed
Current v2 nodes enabled; earlier v1 nodes automatically disabled
Validate final CAD geometry and J1 exposure
Completed
Measured Boolean intersections, bounds, support slices, pipeline reports and STEP read-back below
Positive PCB retention in every direction
Failed
No positive +X restraint: board slides 0.1–5 mm toward USB without plastic interference; accessible outline has no forward shoulder or usable mounting holes before the mandated stop plane
Guarantee clearance to every physically populated part
Failed / blocked
J2 is hidden, not confirmed unpopulated; its stored 4.8 mm header would interfere with the low roof
Board installation/removal
Completed as sampled CAD study
Seven poses clear fixed geometry with clips held open; continuous deformable-path and physical handling tests not verified
Snap lid CAD engagement
Completed, PROVISIONAL
Two XY arms, 0.4 mm nominal detents, 3 mm stepped overlap; physical force/cycling not verified
Combined board/enclosure isometric
Completed
Corrected filtered view linked below; initial renderer included disabled models
Hardware
Completed
None
Physical print, fit, force and life testing
Unattempted
No printed specimen or calibrated printer supplied
Individual pipeline-derived STEP assets were downloaded and inspected instead
Current assets and nodes
3D Model
3D Model
The model cards offer source, STL, STEP, OBJ, 3MF and GLB downloads. Use the installed project transform for assembly; reorient parts separately in the slicer.
Earlier Enclosure base v1 (a97c73ca-53cc-4430-a5bf-615337829e55) and Enclosure lid v1 (50c65cb1-968e-4793-84d4-bed157a6998e) remain automatically disabled. Board layout UID c40fb35f-9deb-3c28-fa06-42d94685a157.defaultlayout remains at origin with unchanged orientation and dimensions.
Rendered image inspected: correctly scaled gray enclosure, exposed board end and separate base/lid seam. The first render included disabled v1 models and hidden J2; one focused presentation recovery filtered to the 14 enabled component models plus the two v2 mechanical nodes. No Enabled rules were manually changed for rendering. Browser-interactive visibility was not separately tested. The malformed outboard J1 copper/outline relationship is not validated by this picture.
Measured board and component inputs
Nominal PCB: 29.0 × 11.2 × 1.30 mm; X -14.5…14.5, Y -5.6…5.6, top Z=0. Actual stored substrate value 1.29936 mm; enclosure follows the user's 1.30 mm nominal datum. Rear corners R2; USB-end corners square.
J1 is the bottom PCB USB-A plug at (15.4,0), 270°. Its footprint/contact geometry extends beyond the stored outline. Conservative keep-out begins X=9.4. Nothing in this work repairs or qualifies that board/connector geometry.
Downloaded package GLBs use Y-up delivery coordinates; their Y range is the package height after mapping to the board Z-up datum. All saved local model transforms are identity. Measured enabled package maxima: R 0.35, C 0.50, U4 0.60, Y1 0.901, U1 1.12, U2 1.09944, U3 0.942, LED1 1.10 mm. Source height bound is 1.20 mm, an intentionally rounded envelope, not a datasheet manufacturing maximum.
The pre-existing Hiding J2 model rule sets J2 model active=false. Its measured model is 4.8 mm above the seating plane with tails to -3.0 mm. Hidden is not synonymous with unpopulated. If populated, roof clearance and bottom-pin clearance fail: this candidate must not be used without resolving J2.
No enabled bottom component bodies. Underside vias and exposed pads were inspected separately rather than treating the absence of bodies as proof of empty copper.
Exact envelope and dimensions
All dimensions mm; both CAD files share PCB top Z=0, not a recentered shell origin.
Table
Dimension
Value
Closed enclosure, plastic only
27.65 × 19.20 × 11.50
X range
-18.50…+9.15
Y range
-9.60…+9.60
Z range
-5.70…+5.80
Ordinary wall
3.00
Floor and roof
2.40 each
Ordinary PCB-edge / inner-wall gap
1.00
Floor inner surface
Z=-3.30
Roof inner surface
Z=+3.40
Bare PCB underside / floor gap
2.00
Roof / tallest enabled model gap
2.28, U1
Roof / rounded 1.20 mm height-bound gap
2.20
Stop behind conservative J1 keep-out
0.25
Exterior corner radius
3.00
Reduced base lip / cover skirt
1.50 / 1.30
Stepped overlap
3.00
Radial lip/skirt gap
0.20 per side, PROVISIONAL
Base-lip / roof vertical gap
0.20, PROVISIONAL
Side shadow recess
0.50 deep × 0.50 high
Lid detent engagement / extra groove depth
0.40 / 0.20, PROVISIONAL
PCB hook overlap / top free play
0.40 / 0.20, PROVISIONAL
Ordinary enclosure dimensions follow the supplied fixed rules. Exceptions are localized retention features, the reduced mating joint, and the completely open USB end. No front cross-wall is added; it would conflict with connector exposure and the dense front electronics. Overall height cannot resemble a sub-5-mm thin shell while retaining the specified 2.4-mm floor/roof and ≥2-mm upper/lower clearances.
Final measured geometry checks
The upload pipeline reports:
Table
Part
Size
Volume
Solid / face count
Base v2
27.65 × 19.20 × 8.90
2115.0384 mm³
1 / 103
Lid v2
27.65 × 19.20 × 5.60
1445.0298 mm³
1 / 42
Both downloaded pipeline STEP files are valid, single analytic solids; their volumes and bounds match the source and pipeline reports. Converted GLBs also retain the source X offset and correct millimeter-to-meter scale. Source CAD checks after final Booleans, in saved installed coordinates:
PASS: base/lid unintended intersection 0 mm³.
PASS: base/nominal PCB and lid/nominal PCB intersections 0 mm³; intended underside bearing is face contact, not solid penetration.
PASS: every enabled component's conservative footprint-sized box at its measured height has 0 mm³ intersection with plastic. This is envelope evidence, not qualified manufacturer/solder tolerances.
PASS: plastic intersecting the entire half-space X≥9.4 is 0 mm³, covering J1 above, below and both sides. All plastic ends at X=9.15.
PASS: source and pipeline solids are nonempty/manifold with no floating solid reported.
FAIL: PCB translated +X by 0.1, 0.5, 1, 2 and 5 mm still has 0 mm³ interference with the base. Thus forward retention is absent, not merely untested.
NOT VERIFIED: exact female USB-A receptacle shell insertion sweep, receptacle retention/friction, board-edge plating and the unsupported outboard copper geometry. The conservative keep-out is respected, but it is not a proof that the current PCB mates with a real port.
Underside supports and retention
Four narrow distributed perimeter lands replace central bosses, using the explicit task permission for verified bare edge strips. They end at Z=-1.30. Final geometry sliced immediately below the seat gives four distinct contact patches:
Table
X contact interval
Y contact interval
Area
Nearest known via copper clearance
-11.5…-9.5
+5.1…+5.6
1.00 mm²
0.475 mm
+7.0…+8.5
+5.1…+5.6
0.75 mm²
approximately 1.43 mm
-4.0…-3.0
-5.6…-5.1
0.50 mm²
>2 mm
+7.2…+8.5
-5.6…-5.1
0.65 mm²
0.741 mm
These contacts avoid J1 pads, J2 pin locations and all inspected via disks. The nearest clearances are below the preferred 1 mm but positive in the known layout; no solder fillet envelope is available for unexpected underside solder contamination. Inspect a real board for solder, burrs, mask damage and warpage before seating. There are no risky central bosses, invented holes or contact over functional test pads. Support-to-support span is below 25 mm (well below 50 mm).
Two fixed +Y lips and two -Y flexible clips prevent simple vertical lift without the lid. Rear stops resist -X travel. They do not prevent +X escape. Friction must not be represented as positive axial capture. Resolution requires an authorized, verified capture feature (for example an actual PCB notch/mounting feature or a newly justified safe connector shoulder) or a user-approved change in retention requirements. No such change was made.
PCB clip nominal bending thickness 1.2 mm, effective conservative span 8 mm and deflection 0.65 mm give 1.5*t*d/L² = 1.828%, below the provisional 2% PETG target. This is a small-deflection estimate, not a stress-concentration/creep/life qualification. The clips have tapered roots and release-accessible upper tips.
Installation, lid closure and service intent
Print and remove supports; remove the lid. Do not attempt assembly if J2 is fitted or if the board/USB geometry differs.
Hold the two -Y PCB clip tips outward approximately 0.65 mm. Tilt the PCB about its +Y edge by approximately 20°, with the -Y edge raised.
Approach with about 1 mm -Y offset, tuck the +Y edge beneath its fixed lips, and return Y offset to zero. Lower the -Y edge onto the support lands and release the clips. The USB end never passes through a boxed aperture.
Lower the lid vertically. Its two horizontal XY arms move outward over 45° lead-ins and return into the side grooves. To remove, gently spread the exposed arm ends and lift; use a small blunt tool if finger purchase is insufficient. Then release PCB clips, tilt up and withdraw in reverse.
Seven representative board-plus-component-envelope poses were collision-free against fixed base geometry with the clip obstruction removed to represent held-open clips: Y=-1/-0.5/0 mm at 20°, then 15°/10°/5°/0° at Y=0. This checks the intended installation trajectory at sample poses; it does not model flexure deformation, continuous minimum clearance, human access forces or repeated removal. Those remain physical-fit tests.
Lid nominal conservative arm span 12 mm, in-plane thickness 1.3 mm, and 0.6 mm deflection give estimated strain 0.8125%. The 0.4-mm detents and 0.2-mm additional groove clearance are PROVISIONAL. Local 0.9-mm residual groove wall is above two nozzle diameters but deserves coupon and durability testing. Segmented detents replace a continuous bead as a documented domain exception to obtain controlled XY bending within the specified print orientation. No qualified cycle-life claim is made.
FDM and printability
PETG, 0.4 mm nozzle, nominal 0.2 mm layers, gray #9a9a9a. Printer/build volume and calibrated shrinkage/fit not supplied; build-volume fit NOT VERIFIED.
Base: open side up, translate Z by +5.70 in the slicer so its broad floor exterior is on the bed. Pipeline warns of 8 down-facing planar faces totaling 59.6208 mm², including clip relief ceilings. Base is not guaranteed support-free. Use accessible removable support under horizontal PCB cantilevers; keep support off bearing lands, hooks and mating faces. The final relief provides 2.0 mm underside access and nominal 1.0 mm free-tip relief. Inspect/clear remnants so they cannot immobilize springs.
Lid: rotate 180° about X and translate Z by +5.80 for its broad exterior roof face on the bed. The installed-view report's 408.4429 mm² downward-face warning is largely the roof underside and is removed by this print orientation. Skirt and detent lead-ins are designed to rise from the roof, preserving XY flexure direction. Support-free lid printing is the preferred starting configuration, subject to slicer review.
Ordinary wall 3.0 mm and floor/roof 2.4 mm are unchanged; skirt 1.3 mm and PCB beam 1.2 mm. Functional slots are nominal 1 mm. Small bead tips are owned by the snap profile rather than treated as standalone thin walls.
No screws, inserts, hardware models, vents, text, logos, keyring features or added controls. Interior debug/LED access was not added. No thermal, impact, waterproofing or electrical safety qualification is implied.
Iteration and remaining blockers
Initial build plus two focused CAD repairs used; no repair budget remains:
Lid skirt seating plane corrected to restore 3.0 mm actual overlap (v2 lid).
PCB spring relief enlarged for nominal 1.0 mm tip gap and 2.0 mm underside support-removal access (v2 base).
One presentation recovery excluded disabled models from the render; this was not CAD repair. Best candidate is the enabled v2 pair. It is preserved as an incomplete prototype, not a final mechanically accepted enclosure.
Warning: physical J2 population unknown; hidden header would not fit. Actual USB-A mating remains unverified because footprint/copper extends beyond the stored PCB outline. Snap clearances, material response, release ergonomics, support removal and print tolerances require real testing. Perimeter landing safety is based on known layout geometry, not physical solder inspection.
Info: asset compilation, separate ROOT placement, read-back, current combined rendering and per-part STEP inspection are complete. Completion of these assigned CAD operations does not mean the overall enclosure goal is complete.